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Cxl^J^S . /^f4 . — -
THE DESCENT OF MAN,
AND
SELECTION IN RELATION TO SEX.
THE
DESCENT OF MAN,
SELECTION IN RELATION TO SEX.
By CHABLES DAEWIN, M.A., F.E.S.
SECOND EDITION, REVISED AND AUGMENTED.
TWENTY-NINTH THOUSAND.
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1890.
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PBEFACE TO THE SECOND EDITION.
During the successive reprints of the first edition of thiis work,
published in 1871, I was able to introduce several important
corrections; and now that more time has elapsed, I have
endeavoured to profit by the fiery ordeal through which. the
book has passed, and have taken advantage of all the criticisms,
which seem to me sound. I am also greatly indebted to a htrge
number of correspondents for the communication of a surprising
number of new facts and remarks. These have been so numerous, *
that I have been able to use only the more important ones; and
of these, as well as of the more important corrections, I will
append a list. Some new illustrations have been introduced,
and four of the old drawings have been replaced by better ones,
done from life by Mr. T. ,W. Wood. I must especially call
attention to some observations which I owe to the kindness of
Prof. Huxley (given as a supplement at the end of Part I.), on
the nature of the differences between the brains of man and the
higher apes. I have been particularly glad to give these obser-
vations, because during the last few years several memoirs on the
subject have appeared on the Continent, and their importance
has been, in some cases, greatly exaggerated by popular writers.
I may take this opportunity of remarking that my critics
frequently assume that I attribute all changes of corporeal
structure and mental power exclusively to the natural selection
of such variations as are often called spontaneous; whereas,
even in the first edition of the e Origin of Species/ 1 distinctly
stated that great weight must be attributed to the inherited
effects of use and disuse, with respect both to the body and
mind. I also attributed some amount of modification to the
direct and prolonged action of changed conditions of life. Some
allowance, too, must be made for occasional reversions of
vi ' Preface to the Second Edition.
struoture; nor must we forget what I have called " correlated*
growth, meaning, thereby, that various parts of the organisation
are in some unknown manner so connected, that when one part
varies, so do others- and if variations in tho one are accu-
mulated by selection, other parts will be modified. Again, it
has been said by several critics, that when I found that many
details of structure in man could not be explained through
natural selection, I invented sexual selection ; I gave, however,
a tolerably clear sketch of this principle in the first edition oi
the ' Origin of Species/ and I there stated that it was applicable
to man. This subject of sexual selection has been treated at
full length in the present work, simply because an opportunity was
here first afforded me. I have been struck with the likeness of
many of the half-favourable criticisms on sexual selection, with
those which appeared at first on natural selection; such as,
that it would explain some few details, but certainly was not
applicable to the extent to which I have employed it. My
conviction of the power of sexual selection remains unshaken ;
but it is probable, or almost certain, that several of my con-
clusions will hereafter be found erroneous; this can hardly fail
to be the case in the first treatment of a subject. When
naturalists have become familiar with the idea of sexual selection,
it will, as I believe, be much more largely accepted; and it
has already been fully and favourably received by several capable
judges.
Down, Bbckevhah, Kent,
September 1874,
TABLE
PBINCIPAL ADDITIONS AND COKBECTIONS TO THE
PRESENT EDITION.
Firet
Edition.
Present
Edition.
Vol. I.
Page
Page
22
15-17
/Discussion on the rudimentary points in the
\ human ear revised.
26
19
Cases of men born with hairy bodies.
27, note.
20, note.
Mantegazza on the last molar tooth in man.
29
23
The rudiments of a tail in man.
jBianconi on homologous structures, as ex-
82, note.
24, note,
< plained by adaptation on mechanical
( principles.
40
70
Intelligence in a baboon.
42
71
Sense of humour in dogs.
44
72-3
(Further facta on imitation in man and
\ animals.
47
75
Reasoning power in the lower animals.
50
80
Acquisition of experience by animals.
53
83
Power of abstraction in animals.
58
88-9
(Power of forming concepts in relation to
\ language.
64
92
(Pleasure from certain sounds, colours, and
\ forms.
78
104
Fidelity in the elephant.
79
104
Galton on gregariousness of cattle.
81
105-6
Parental affection.
90, note.
Q12-113, \
\ note. /
Persistence of enmity and hatred.
91
94
97
112
122
124, note.
125, note.
128-9
146
114
117, note.
120, note.
28
35-6
39, note.
36-8, note.
41-2
55, note.
i Nature and strength of shame, regret, and
\ remorse.
Suicide amongst savages.
The motives of conduct.
Selection, as applied to primeval man.
Resemblances between idiots and anim ate
Division of the malar bone.
Supernumerary mammro and digits.
(Further cases of muscles proper to animals
\ appearing in man.
Broca: average capacity of skull diminished
by the preservation of the inferior members
of society.
viii Table of the Principal Additions and
First
Edition.
Vol. I.
Page
149
150
169
180
193
208, note.
209
239
245
250
256
/«
275-6
290
301
314
397
401
412
417
Page
57
58-9
134-5
143
151
161, note.
163
188-190
195-6
199-206
209-210
224-5
(Belt on advantages to man from his hair*
235
243-4
254
315
255-6
327
264
338
272
339
273
345
277
349
280
350
281
351
282
354
284-5
359
288, note.
366
292-3
387
308
315
319
324-5
326
(Disappearance of the tail in man and certain
\ monkeys.
(Injurious forms of selection in civilised
\ nations.
(Indolence of man, when free from a struggle
\ for existence.
(■Gorilla protecting himself from rain with his
\ hands.
Hermaphroditism in fish.
Kudimentary mammae in male mammals.
f Changed conditions lessen fertility and cause
{ ill-health amongst savages.
/Darkness of skin a protection against the
\ sun.
fNote hy Professor Huxley on the develop-
• ment of the brain in man and apes.
'Special organs of male parasitic worms for
s holding the female.
j Greater variability of male than female;
direct action of the environment in causing
differences between the sexes.
Period of development of protuberances
on birds' heads determines their trans-
mission to one or both sexes.
Causes of excess of male births.
Proportion of the sexes in the bee family.
/Excess of males perhaps sometimes deter-
l mined by selection.
Bright colours of lowly organised animals.
Sexual selection amongst spiders.
Cause of smallness of male spiders.
Use of phosphorescence of the glow-worm.
The humming noises of flies.
Use of bright colours to Hemiptera (bugs).
Musical apparatus of Homoptera.
("Development of stridiilating apparatus in
\ Orthoptera.
("Hermann Miiller on sexual differences of
\ bees.
Sounds produced by moths.
Display of beauty by butterflies.
("Female butterflies, taking the more active
\ part in courtship, brighter than their males.
further cases of mimicry in butterflies and
moths.
/Cause of bright and diversified colours of
I caterpillars.
Corrections to the Present Edition.
IX
First
Edition.
Vol.IL
Page
2
14
23
26
30
32
36
72
91
y 108
,/ll8
120
124
147-150
152
157
232
247
Present
Edition.
Page
331
341
347
349
352
353-
357
383
398
411
417
419
423
438-441
443
446
495-6
505
248
256
506
513-514
260
516
266
286
299
521
534
542-3
316
556
337
572
356
586
859 et 8eq.
588 et seq.
373
598-9
380
603
Brash-like scales of male Mallotus.
(Further facts on courtship of fishes, and the
\ spawning of Macropus.
Dufosse* on the sounds made by fishe3.
Belt on a frog protected by bright colouring.
Further facts on mental powers of snakes.
Sounds produced by snakes ; the rattlesnake.
Combats of Chameleons.
Marshall on protuberances on birds* heads.
(Further facts on display by the Argus
pheasant
Attachment between paired birds.
Female pigeon rejecting certain males.
(Albino birds not finding partners, in a state
\ of nature.
Direct action of climate on birds' colours.
(Further facts on the ocelli in the Argus
\ pheasant.
Display by humming-birds in courtship.
/Cases with pigeons of colour transmitted to
' i one sex alone.
Taste for the beautiful permament enough
to allow of sexual selection with the lower
animals,
i Horns of sheep originally a masculine
\ character.
Castration affecting horns of animals.
Prong-horned variety of Cervus virginianus.
(Relative sizes of male and female whales and
seals.
Absence of tusks in male miocene pigs.
Dobson on sexual differences of bats.
Reeks on advantage from peculiar colouring.
(Difference of complexion in men and women
of an African tribe.
Speech subsequent to singing.
(Schopenhauer on importance of courtship to
\ mankind.
f Revision of discussion on communal marriages
\ and promiscuity.
(Power of choice of woman in marriage,
\ amongst savages.
(Long-continued habit of plucking out hairs
\ may produce an inherited effect.
CONTENTS.
Introduction . Pages 1-4
PART I.
THE DESCENT OR ORIGIN OF MAN.
CHAPTER I.
The Evidence of the Descent op Man from some Lower Form.
PAGl
Nature of the evidence bearing on the origin of man — Homologous
structures in man and the lower animals — Miscellaneous points
of correspondence — Development — Rudimentary structures,
muscles, sense-organs, hair, bones, reproductive organs, &c—
The bearing of these three great classes of facts on the origin of
man ■ '• . 5
CHAPTER II.
On the Manner of Development of Man from some Lower
Form.
Variability of body and mind in man — Inheritance — Causes of
variability — Laws of variation the same in man as in the lower
animals— Direct action of the conditions of life — Effects of the
increased use and disuse of parts — Arrested development — Re-
version — Correlated variation — Rate of Increase — Checks to
increase — Natural selection — Man the most dominant animal in
the world— Importance of his corporeal structure — The causes
which have led to his becoming erect— Consequent changes of
structure — Decrease in size of the canine teeth — Increased size
and altered shape of the skull— Nakedness — Absence of a tail-~
Defenceless condition of man . 26
CHAPTER III.
Comparison of the Mental Powers of Man and the Lower
Animals.
The difference in mental power between the highest ape and the
lowest savage, immense— Certain instincts in common — The
emotions— Curiosity—Imitation— Attention — Memory— Imagi-
nation— Reason— Progressive improvement— Tools and weapons
xii Contents.
PAGl
used by animals — Abstraction, Self^jonsciousness — Language
— Sense of beauty — Belief in God, spiritual agencies, super-
stitions 65
CHAPTER IV.
COMPABISON OF THE MENTAL POWERS OF MAN AND THE IiOWER
Animals — continued,.
The moral sense — Fundamental proposition — The qualities of
social animals — Origin of sociability — Struggle between opposed
instincts — Man a social animal — The more enduring social in-
stincts conquer other less persistent instincts — The social virtues
alone regarded by savages — The self-regarding virtues acquired
at a later stage of development — The importance of the judg-
ment of the members of the same community on conduct —
Transmission of moral tendencies — Summary . 97
CHAPTER V.
On the Development of the Intellectual and Mobal
Faculties during Primeval and Civilised Times.
Advancement of the intellectual powers through natural selec-
tion—Importance of imitation — Social and moral faculties —
Their development within the limits of the same tribe — Natural
selections affecting civilised nations — Evidence that civilised
nations were once barbarous • . , . . . 1 27
CHAPTER VI.
On the Affinities and Genealogy of Man.
Position of man in the animal series — The natural system genea-
logical — Adaptive characters of slight value — Various small
points of resemblance between man and the Quadrumana —
Rank of man in the natural system — Birthplace and antiquity
of man — Absence of fossil connecting-links — Lower stages in
the genealogy of man, as inferred, firstly from his affinities and
secondly from his structure — Early androgynous condition of
the Vertebrata — Conclusion 116
CHAPTER VII.
On the Races of Man.
The nature and value of specific characters — Application to the
races of man — Arguments in favour of, and opposed to, ranking
the so-called races of man as distinct species — Sub-species—
Monogenists and polygenists — Convergence of character -~
Contents. xiii
PAGE
Numerous points of resemblance in body and mind between the
most distinct races of man — The state of man when he first
spread over the earth — Each race not descended from a single
pair — The extinction of races — The formation of races — The
effects of crossing — Slight influence of the direct action of the
conditions of life — Slight or no influence of natural selection
Sexual selection 166
PART II.
SEXUAL SELECTION.
CHAPTER VIH.
Principles of Sexual Selection,
Secondary sexual characters — Sexual selection — Manner of action
— Excess of males — Polygamy — The male alone generally
modified through sexual selection — Eagerness of the male —
Variability of the male — Choice exerted, by the female — Sexual
compared with natural selection — Inheritance at corresponding
periods of life, at corresponding seasons of the year, and as
limited by sex — Relations between the several forms of inheri-
tance — Causes why one sex and the young are not modified
through sexual selection — Supplement on the proportional num-
bers of the two sexes throughout the animal kingdom — The
proportion of the sexes in relation to natural selection . 207
CHAPTER IX.
Secondary Sexual Characters in the Lower Classes of
the Animal Kingdom.
These characters absent in the lowest classes — Brilliant colours —
Mollusca — Annelids — Crustacea, secondary sexual characters
strongly developed; dimorphism; colour; characters not ac-
quired before maturity — Spiders, sexual colours of; stridulation
by the males— Myriapoda ...... 2G0
CHAPTER X.
Secondary Sexual Characters of Insects.
Diversified structures possessed by the males for seizing the
females — Differences between the sexes, of which the mean-
ing is not understood— Difference in size between the sexes —
Thysanura — Diptera — Hemiptera — Homoptera, musical powers
xiv Contents.
possessed by the males alone — Orthoptera, musical instruments
of the males, much diversified in structure ; pugnacity ; colours —
Neuroptera sexual differences in colour— Hymenoptera, pug-
nacity and colours — Coleoptera, colours; furnished with great
horns, apparently as an ornament; battles; stridulating organs
generally common to both sexes . . 274
CHAPTER XL
Insects, continued .-— Order Lepidoptera.
(BUTTEBFLDBS AND MOTHS.)
Courtship of butterflies— Battles— Ticking noise — Colours common
to both sexes, or more brilliant in the males— Examples — Not
due to the direct action of the conditions of life — Colours
adapted for protection — Colours of moths — Display — Perceptive
powers of the Lepidoptera— Variability — Causes of the difference
in colour between the males and females — Mimicry, female
butterflies more brilliantly coloured than the males — Bright
colours of caterpillars — Summary and concluding remarks on
the secondary sexual characters of insects — Birds and insects
compared 307
CHAPTEB XII.
Secondary Sexual Characters of Fishes, Amphibians, and
Reptiles.
Fishes: Courtship and battles of the males— Larger size of the
females — Males, bright colours and ornamental appendages;
other strange characters — Colours and appendages acquired by
the males during the breeding-season alone — Fishes with both
sexes brilliantly coloured — Protective colours — The less con-
spicuous colours of the female cannot be accounted for on the
principle of protection — Male fishes building nests, and taking
charge of the ova and young. Amphibians: Differences in
structure and colour between the sexes — Vocal organs. Eep-
tiles: Chelonians — Crocodiles — Snakes, colours in some cases
protective — Lizards, battles of — Ornamental appendages —
Strange differences in structure between the sexes — Colours —
Sexual differences almost as great as with birds . , 330
CHAPTEB XIII.
Secondary Sexual Characters of Birds.
Bexual differences — Law of battle—Special weapons — Vocal
organs — Instrumental music — Love-antics and dances — Deco-
rations, permanent and seasonal — Double and single annual
moults— Display of ornaments by the males • . flfif
Contents. xv
CHAPTER XIV.
Bibbs— eontfuaed,
PAOI
Choice exerted by the female— Length of courtship— Unpaired
birds— Mental qualities and taste for the beautiful— Preference
or antipathy shewn by the female for particular males — Vari-
ability of birds— Variations sometimes abrupt— Laws of varia-
tion — Formation of ocelli — Gradations of character — Case of
Peacock, Argus pheasant, and Urosticte • . , 404
CHAPTER XV.
Birds— eoniinued.
Discussion as to why the males alone of some specie*, and both
sexes of others are brightly coloured — On sexually-limited
inheritance, as applied to various structures and to brightly-
coloured plumage— Nidification in relation to colour — Loss of
nuptial plumage during the winter . . . « 444
CHAPTER XVL
Bibds — conducted.
The immature plumage in relation to the character of the plumage
in both sexes when adult — Six classes of cases — Sexual differ-
ences between the males of closely-allied or representative
species — The female assuming the characters of the male —
Plumage of the young in relation to the summer and winter
plumage of the adults— On the increase of beauty in the birds
of the world — Protective colouring — Conspicuously-coloured
birds— Novelty appreciated— Summary of the four chapters on
birds .... . . . . 463
CHAPTER XVH.
Secondary Sexual Chabaotebs or Mammals.
The law of battle — Special weapons, confined to the males — Cause
of absence of weapons in the female — Weapons common to both
sexes, yet primarily acquired by the male— Other uses of such
weapons — Their high importance— Greater size of the male —
Means of defence — On the preference shewn by either sex in the
pairing of quadrupeds ...... 500
CHAPTER XVIII.
Secondary Sexual Chabaotebs of Mammals— continued.
Voice — Remarkable sexual peculiarities in seals — Odour — Develop-
ment of the hair — Colour of the hair and skin— Anomalous
xvi Contents.
case of the female being more ornamented than the male —
Colour and ornaments due to sexual selection — Colour acquired
for the sake of protection— Colour, though common to both
sexes, often due to sexual selection — On the disappearance of '
spots and stripes in adult quadrupeds — On the colours and orna-
ments of the Quadrumana — Summary .... 525
PART IIL
SEXUAL SELECTION IN BELATION TO MAN
AND CONCLUSION.
CHAPTER XIX.
Secondary Sexual Characters of Man
Differences between man and woman — Causes of such differences,
and of certain characters common to both sexes— Law of battle
— Differences in mental powers, and voice— On the influence
of beauty in determining the marriages of mankind — Attention
paid by savages to ornaments — Their ideas of beauty in woman
— The tendency to exaggerate each natural peculiarity . 556
CHAPTER XX.
Secondary Sexual Characters cf Man— continued.
On the effects of the continued selection of women according to a
different standard of beauty in each race — On the causes which
interfere with sexnal selection in civilised and savage nations
— Conditions favourable to sexual selection during primeval
times — On the manner of action of sexual selection with man-
kind — On the women in savage tribes having some power to
choose their husbands — Absence of hair on the body, and
development of the beard — Colour of the skin — Summary . 585
CHAPTER XXI.
General Summary and Conclusion.
Main conclusion that man is descended from some lower form-
Manner of development — Genealogy of man — Intellectual and
moral faculties — Sexual selection — Concluding remarks . 606
Supplemental Note
Index
THE DESCENT OF MAN;
SELECTION IN EELATION TO SEX.
INTRODUCTION.
The nature of the following work will be best understood by a
brief account of how it came to be written. During many years
I collected notes on the origin or descent of man, without any
intention of publishing on the subject, but rather with the
determination not to publish, as I thought that I should thus
only add to the prejudices against my views. It seemed to me
sufficient to indicate, in the first edition of my 'Origin of
Species/ that by this work "light would be thrown on the
" origin of man and his history ; w and this implies that man must
be included with other organic beings in any general conclusion
respecting his manner of appearance on this earth. Now the
case wears a wholly different aspect. When a naturalist like
Carl Vogt ventures to say in his address as President of the
National Institution of Geneva (1869), "personne, en Europe
" au moins, n'ose plus soutenir la creation independante et de
" toutes pieces, des especes," it is manifest that at least a large
number of naturalists must admit that species are the modified
descendants of other species; and this especially holds good with
the younger and rising naturalists. The greater number accept
the_agency of natural selection ; though some urge, whether with
justice the future must decide, that I have greatly overrated its
importance. Of the older and honoured chiefs in natural science,
many unfortunately are still opposed to evolution in every
form.
In consequence of the views now adopted by most naturalists,
and which will ultimately, as in every other case, be followed by
Introduction.
t'
others who are not scientific, I have been led to put together
my notes, so as to see how far the general conclusions arrived at
in my former works were applicable to man. This seemed all
the more desirable, as I had never deliberately applied these
views to a species taken singly. When we confine our attention
to any one form, we are deprived of the weighty arguments
derived from the nature of the affinities which connect together
whole groups of organisms— their geographical distribution in
past and present times, and their geological succession. The
homological structure, embryologica! development, and rudi-
mentary organs of a species remain to be considered, whether it
be man or any other animal, to which our attention may be
directed ; but these great classes of facts afford, as it appears to
me, ample and conclusive evidence in favour of the principle of
gradual evolution. The strong support derived from the other
arguments should, however, always be kept before the mind.
The sole object of this work is to consider, firstly, whether
man, like every other species, is descended from some pre-
existing form; secondly, the manner of his development; and
thirdly, the value of the differences between the so-called races
of man. As I shall confine myself to these points, it will not be
necessary to describe in detail the differences between the several
races— an enormous subject which has been fully discussed in
many valuable works. The high antiquity of man has recently
been demonstrated by the labours of a host of eminent men,
beginning with M. Boucher de Perthes ; and this is the indis-
pensable basis for understanding his origin. I shall, therefore,
take this conclusion for granted, and may refer my readers to
the admirable treatises of Sir Charles Lyell, Sir John Lubbock,
and others. Nor shall I have occasion to do more than to allude
to the amount of difference between man and the anthropomor-
phous apes ; for Prof. Huxley, in the opinion of most competent
judges, has conclusively shewn that in every visible character
man differs less from the higher apes, than these do from tho
lower members of the same order of Primates.
This work contains hardly any original facts in regard to man ;
but as the conclusions at which I arrived, after drawing up a
rough draft, appeared to me interesting, I thought that they
might interest others. It has often and confidently been asserted,
that man's origin can never be known : but ignorance more
frequently begets confidence than does knowledge : it is those
who know little, and not those who know much, who so
.positively assert that this or that problem will never be solved
by science. The conclusion that man is the co-descendant with
other species of some ancient, lower, and extinct form, is not in
fyttt oductio?i.
any degree new. Lamarck long ago came to this conclusion,
which has lately been maintained by several eminent naturalists
and philosophers ; for instance, by Wallace, Huxley, Lyell, Vogt,
Lubbock, Buchner, Eolle, &C, 1 and especially by Hackel. This
last naturalist, besides his great work, 'Generelle Morphologie*
(1866), has recently (1868, with a second edit, in 1870), pub-
lished his ' Natiirliche Sehcpfungsgeschichte/ in which he fully
discusses the genealogy of man. If this work had appeared
before my essay had been written, I should probably never have
completed it. Almost all the conclusions at which I have
arrived I find confirmed by this naturalist, whose knowledge on
many points is much fuller than mine. Wherever I have added
any fact or view from Prof. Hackel's writings, I give his autho-
rity in the text ; other statements I leave as they originally stood
in my manuscript, occasionally giving in the foot-notes references
to his works, as a confirmation of the more doubtful or interesting
points.
During many years it has seemed to me highly probable that
sexual selection has played an important part in differentiating
the races of man ; but in my ' Origin of Species ' (first edition, p.
199) I contented myself by merely alluding to this belief. When
I came to apply this view to man, I found it indispensable to
treat the whole subject in full detail. 2 Consequently the second
part of the present work, treating of sexual selection, has ex-
tended to an inordinate length, compared with the first part;
but this could not be avoided.
I had intended adding to the present volumes an essay on the
expression of the various emotions by man and the lower animals.
My attention was called to this subject many years ago by
Sir Charles Bell's admirable work. This illustrious anatomist
1 As the works of the first-named Nat./ Modena, 1S67, p. 81) a very
authors are so well known, I need curious paper on rudimentary cha-
not give the titles ; but as those of racters, as bearing on the origin of
the latter are less well known in man. Another work has (1869)
England, I will give them : — ' Sechs been published by Dr. Francesco
Vorlesungen iiber die Darwin'sche Barrago, bearing in Italian the title
Theorie :' zweite Auflage, 1868, von of " Man, made in the image of God,
Dr. L. Buchner ; translated into " was also made in the image of the
French under the title * Conferences " ape."
sur la Theorie Darwinienne/ 1869. 2 Prof. Hackel was the only
* Der Mensch, im Lichte der Dar- author who, at the time when this
win'sehe Lehre,* 1865, von Dr. F. work first appeared, had discussed
Kolie. I will not attempt to give the subject of sexual selection, and
leferences to all the authors who had seen its full importance, since
have taken the same side of the the publication of the ' Origin '; and
question. Thns G. Canestrini has this he did in a very able manner io
published ('Annario del la Soc cL his various works.
a 2
Introdticiion.
maintains that man is endowed with certain muscles solely for
the sake of expressing his emotions. As this view is obviously
opposed to the belief that man is descended from some other and
lower form, it was necessary for me to consider it I likewise
wished to ascertain how far the emotions are expressed in the
same manner by the different races of man. But owing to the
length of the present work, I have thought it better to reserve
my essay for separate publication.
( 5 )
Part I.
THE DESCENT OE OEIGIN OF MAN.
CHAPTER I.
The Evidence of the Descent of Man from some
Lower Form.
Mature of the evidence bearing on the origin of man — Homologous
structures in man and the lower animals — Miscellaneous points ol
correspondence — Development — Rudimentary structures, muscles, sense-
organs, hair, bones, reproductive organs, &c. — The bearing of these three
great classes of facts on the origin of man.
He who wishes to decide whether man is the modified descendant
of some pre-existing form, would probably first enquire whether
man varies, however slightly, in bodily structure and in mental
faculties; and if so, whether the variations are transmitted to
his offspring in accordance with the laws which prevail with the
lower animals. Again, are the variations the result, as far as
our ignorance permits us to judge, of the same general causes,
and are they governed by the same general laws, as in the case
of other organisms ; for instance, by correlation, the inherited
effects of use and disuse, &c. ? Is man subject to similar mal-
conformations, the result of arrested development, of reduplication
of parts, &c, and does he display in any of his anomalies rever-
sion to some former and ancient type of structure ? It might
also naturally be enquired whether man, like so many other
animals, has given rise to varieties and sub-races, differing but
slightly from each other, or to races differing so much that they
must be classed as doubtful species? How are such races
distributed over the world; and how, when crossed, do they
react on each other in the first and succeeding generations?
And so with many other points.
The enquirer would next come to the important point,
whether man tends to increase at so rapid a rate, as to lead to
occasional severe struggles for existence; and consequently to
6 The Descent of Man. Part I,
beneficial variations, whether in body or mind, being preserved,
and injurious ones eliminated. Do the races or species of men,
whichever term may be applied, encroach on and replace one
another, so that some finally become extinct ? We shall see that
all these questions, as indeed is obvious in respect to most of
them, must be answered in the affirmative, in the same manner
as with the lower animals. But the several considerations just ■
referred to may be conveniently deferred for a time : and we ;
will first see how far the bodily structure of man shows traces, \
more or less plain, of his descent from some lower form. In 1
succeeding chapters the mental powers of man, in comparison/
with those of the lower animals, will be considered. [
The Bodily Structure of Man. — It is notorious that man is
constructed on the same general type or model as other mam-
mals. All the bones in his skeleton can be compared with
corresponding bones in a monkey, bat, or seal. So it is with his
muscles, nerves, blood-vessels and internal viscera. The brain,
the most important of all the organs, follows the same law, as
shewn by Huxley and other anatomists. Bischoff, 1 who is a
hostile witness, admits that every chief fissure and fold in the
brain of man has its analogy in that of the orang ; but he adds
that at no period of development do their brains perfectly agree ;
nor could perfect agreement be expected, for otherwise their
mental powers would have been the same. Vulpian 2 remarks :
'" !Les differences reelles qui existent entre Tencephale de
" rhomme et celui des singes superieurs, sont bien minimes. II
" ne faut pas se faire delusions a cet egard. L'homme est bien
" plus pres des singes anthropomorphes par les caracteres
" anatomiques de son cerveau que ceux-ci ne le sont non-
"seulement des autres mammiferes, mais meme de certains
" quadrumanes, des guenons et des macaques." But it would
be superfluous here to give further details on the correspondence
between man and the higher mammals in the structure of the
brain and all other parts of f the body.
It may, however, be worth while to specify a few points, not
Erectly or obviously connected with structure, by which this
correspondence or relationship is well shewn.
Man is liable to receive from the lower animals, and to com-
1 " Grosshirnwindungen des Men- in the Preface to this edition,
schen,' 1868, s. 96. The conclusions 2 ' Lee. sur la PRys/ 1866, p. 890,
of this author, as well as those of as quoted by M. Dally, ' L'Ordre des
Gratiolet and Aeby, concerning the Primates et le TransformisnT?,* 186 6^
brain, will be discussed by Prof. p. 29.
Huxley in the Appendix alluded to
€ha?, I. Homological Structures. 7
rrmnicate to them, certain diseases, as hydrophobia, variola, the
glanders, syphilis, cholera, herpes, &c. ; 3 and this fact proves tha
close similarity 4 of their tissues and blood, both in minute
structure and composition, far more plainly than does their
comparison under the best microscope, or by the aid of the best
chemical analysis. Monkeys are liable to many of the same non-
contagious diseases as we are; thus Eengger, 5 who carefully
observed for a long time the Cebus Azarce in its native land,
found it liable to catarrh, with the usual symptoms, and which/
when often recurrent, led to consumption. These monkeys
suffered also from apoplexy, inflammation of the bowels, and
cataract in the eye. The younger ones when shedding their
milk-teeth often died from fever. Medicines produced the same I
effect on them as on us. Many kinds of monkeys have a strong J
taste for tea, coffee, and spirituous Liquors : they will also, as 1 1
have myself seen, smoke tobacco with pleasure. 6 Brehm asserts!
that the natives of north-eastern Africa catch the wild baboons |
by exposing vessels with strong beer, by which they are made I
drunk. He has seen some of these animals, which he kept in J
confinement, in this state ; and he gives a laughable account of |
their behaviour and strange grimaces. On the following \
morning they were very cross and dismal ; they held their aching
heads with both hands, and wore a most pitiable expression :
when beer or wine was offered them, they turned away with
disgust, but relished the juice of lemons. 7 An American monkey,
an Ateles, after getting drunk on brandy, would never touch it j
again, and thus was wiser than many men. These trifling facts
prove how similar the nerves of taste must be in monkeys and
man, and how similarly their whole nervous system is affected.
Man is infested with internal parasites, sometimes causing
3 Dr. W. Lauder Lindsay has tinct fluids by the same chemical
treated this subject at some length reagent.
in the ' Journal of Mental Science,* 5 * Naturgeschichte der SUuge-
July 1871; and in the * Edinburgh thiere von Paraguay,' 1830, s. 50.
Veterinary Revi«w,' July 1858. 6 The same tastes are common to
4 A Reviewer has criticised some animals much lower in the
(* British Quarterly Review/ Oct. scale. Mr. A. Nicols informs me
1st, 1871, p. 472) what I have here that he Jcept in Queensland, in Aus-
said with much severity and con- tralia, three individuals of the
tempt ; but as I do not use the term Phaseolarctus cinereus ; and that,
identity, 1 cannot see that 1 am without having been taught in any
greatly in error. There appears to way, they acquired a strong taste
me a strong analogy between the for rum, and for smoking tobacco,
same infection or contagion pro- 7 Brehm, * Thierleben,' B. i. 1864,
ducing the same result, or one s. 75, 86. On the Ateles, s. 105.
closely similar, in two distinct ani- For other analogous statements, ges
mais, and the testing of two dis- a. 25, 107.
8 The Descent of Man. p AET £
fatal effects ; and is plagued by external parasites, all of winch
belong to the same genera or families as those infesting other
mammals, and in the case of scabies to the same species. 8 Man
is subject, like other mammals, birds, and even insects, 9 to that
mysterious law, which causes certain normal processes, such as
gestation, as well as the maturation and duration of various
diseases, to follow lunar periods. His wounds are repaired by
the same process of healing; and the stumps left after the
amputation of his limbs, especially during an early embryonic
period, occasionally possess some power of regeneration, as in
the lowest animals. 10
The whole process of that most important function, the
reproduction of the species, is strikingly the same in all mam-
mals, from the first act of courtship by the male, 11 to the birth
and nurturing of the young. Monkeys are born in almost as
helpless a condition as our own infants ; and in certain genera
the young differ fully as much in appearance from the adults, as
do our children from their full-grown parents. 12 It has been
urged by some writers, as an important distinction, that with
man the young arrive at maturity at a much later age than with
any other animal : but if we look to the races of mankind which
inhabit tropical countries the difference is not great, for the
orang is believed not to be adult till the age of from ten to fifteen
years. 13 Man differs from woman in size, bodily strength,
hairiness, &c, as well as in mind, in the same manner as do the
* Dr. W. Lauder Lindsay, * Edin- " sagax, hoc mihi certissime pro-
burgh Vet. Review,' July 1858, " bavit, et curatores ejusdem loci et
p. 13. " alii e ministris confirmaverunt.
9 With respect to insects see Dr. " Sir Andrew Smith et Brehm no-
Laycock, " On a General Law of Vital '* tabant idem in Cynocephalo. II-
Periodicity," * British Association,' " lustrissimus Cuvier etiam narrat
1842. Dr. Macculloch, * Silliman's " multa de h£c re, quS, ut opinor,
North American Journal of Science,' " nihil turpius potest indicari inter
vol. xvii. p. 305, has seen a dog " omnia hominibus et Quadrumanis
suffering from tertian ague. Here- " communia. Narrat enim Cy no-
after I shall return to this subject. " cephalum quendam in furorem in-
10 1 have given the evidence on " cidere aspectu feminarum ali-
this head in' my ' Variation of Ani- " quarum, sed nequaquam accendi
mals and Plants under Domestica- " tanto furore ab omnibus. Sem-
tion/ vol. ii. p. 15, and iiore could "per eligebat juniores, et dignos-
be added. " cebat in turb£, et advocabat voce
11 " Mares e diversis generibus " gestuque."
" Quadrumanorum sine dubio di- 12 This remark is made with re-
" gnoscunt feminas humanas a ma- spect to Cynocephalus and the an-
" ribus. Primum, credo, odoratu, thropomorphous apes by Geoffroy
** postea aspectu. Mr. Youatt, qui Saint-Hilaire and F. Cuvier, * Hist.
44 diu in Hortis Zoologicis (Besti- Nat. des Mammiferes,' torn. i. 1824.
" ariis) medicus animalium erat, ,s Huxley, * Man's Place in N»
u vir ia rebus observandis cautus et ture,' 1863, p. 34.
Chap. I. Homological Structures. 9
two sexes of many mammals. So that the correspondence in
general structure, in the minute structure of the tissues, in
chemical composition and in constitution, between man and the
higher animals, especially the anthropomorphous apes, is ex-
tremely close. —
Embryonic Development. — Man is developed from an ovule,
about the 125th of an inch in diameter, which differs in no
respect from the ovules of other animals. The embryo itself at
a very early period can hardly be distinguished from that of
other members of the vertebrate kingdom. At this period the
arteries run in arch-like branches, as if to carry the blood to
branchiae which are not present in the higher vertebrata, though
the slits on the sides of the neck still remain (/, g, fig. 1),
marking their former position. At a somewhat later period,
when the extremities are developed, " the feet of lizards and
" mammals," as the illustrious Von Baer remarks, " the wings
" and feet of birds, no less than the hands and \ feet of man, all
" arise from the same fundamental form." It is, says Prof.
Huxley, 14 " quite in the later stages of development that the
young human being presents marked differences from the young
" ape, while the latter departs as much from the dog in its
" developments, as the man does. Startling as this last assertion
" may appear to be, it is demonstrably true."
As some of my readers may never have seen a drawing of an
embryo, I have given one of man and another of a dog, at about
the same early stage of development, carefully copied from two
works of undoubted accuracy. 15
After the foregoing statements made by such high autho-
rities, it would be superfluous on my part to give a number of
borrowed details, shewing that the embryo of man closely
resembles that of other mammals. It may, however, be added,
that the human embryo likewise resembles certain low forms
when adult in various points of structure. For instance, the
heart at first exists as a simple pulsating vessel; the excreta
are voided through a cloacal passage ; and the os coccyx projects
14 * Man's Place in Nature/ 1863, magnified, the embryo being twenty-
p. 67. five days old. The internal viscera
15 The human embryo (upper have been omitted, and the uterine ap-
fig.) is from Ecker, * Icones Phys.,* pendages in both drawings removed.
1851-1859, tab. xxx. fig. 2. This I was directed to these figures by
embryo was ten lines in length, so Prof. Huxley, from whose work,
that the drawing is much magnified. * Man's Place in Nature,' the idea of
The embryo of the dog is from giving them was taken. H'ackel has
HischofF, ' Entwicklungsgeschichte also given analogous drawings in his
des Hunde-Eies/ 1845, tab. xi. fig. 4 Sehopfungsgeschichte.'
12 b This drawing is five times
IO
The Descent of Man.
Part I.
Fig. 1. Upper figure human embryo, from Ecker. Lower figure that of a dog,
from Bischofif.
a. Fore-brain, cerebral hemispheres, &c.
b. Mid-brain, corpora quadrigemina.
c. Hind-brain, cerebellum, medulla ob-
longata,
d. Eye.
e Ear.
f. First visceral arch.
p. Second visceral arch.
H. Vertebral columns and muscles in
process of development.
L. Tail or os coccyx.
jjhap. I. Rudiments. i\
like a true tail, " extending considerably beyond the rudi-
" mentary legs." 1 6 In the embryos of all air-breathing vertebrates,
certain glands, called the corpora Wolffiana, correspond with,
and act like the kidneys of mature fishes. 17 Even at a later
embryonic period, some striking resemblances between man and
the lower animals may be observed. Bischoff says that the
convolutions of the brain in a human foetus at the end of the
seventh month reach about the same stage of development as in
a baboon when adult. 18 The great toe, as Prof. Owen remarks, 19
" which forms the fulcrum when standing or walking, is
" perhaps the most characteristic peculiarity in the human
structure;" but in an embryo, about an inch in length, Prof.
Wyman 20 found " that the great toe was shorter than the others ;
" and, instead of being parallel to them, projected at an angle
" from the side of the foot, thus corresponding with the per-
" manent condition of this part in the quadrumana." I will
conclude with a quotation from Huxley, 21 who after asking,
does man originate in a different way from a dog, bird, frog or
fish? says, "the reply is not doubtful for a moment; without
" question, the mode of origin, and the early stages of the
" development of man, are identical with those of the animals
" immediately below him in the scale : without a doubt in
" these respects, he is far nearer to apes than the apes are to
"the dog.*
Jludiments. — This subject, though not intrinsically more
important than the two last, will for several reasons be treated
here more fully. 22 Not one of the higher animals can be named
which does not bear some part in a rudimentary condition ; and
man forms no exception to the rule. Kudimentary organs must
be distinguished from those that are nascent ; though in some
cases the distinction is not easy. The former are either abso-
lutely useless, such as the mammae of male quadrupeds, or the
incisor teeth of ruminants which never cut through the gums ;
or they are of such slight service to their present possessors,
that we can hardly suppose that they were developed under the
16 Prof. Wyman in ' Proc. of 22 I had written a rough copy of
American Acad, of Sciences/ vol. iv. this chapter before reading a valu-
1860, p. 17. able paper, " Caratteri rudimentali
17 Owen, 'Anatomy of Verte- in ordine all* origine del uomo"
brates/ vol. i. p. 533. (' Annuario della Soc. d. Nat.,' Mo-'
18 * Die Grosshirnwindungen des dena, 1867, p. 81), by G. Canestrin'i,
Menschen/ 1868, s. 95. to which paper I am considerably
lB ' Anatomy of Vertebrates/ vol. indebted. Hackel has given admir-
li. p, 553. able discussions on this whole hub-
*• ' Proc. Soc. Nat. Hist.' Boston, ject, under the title of Dysteleology,
1863, vol. ix. p. 185. in his ' Gonerelle Morphologic ' and
-* 1 * Man's Place in Nature/ p. 65. ' Schopfnngsgeschichta.'
1 2 The Descent of Man, Part I,
conditions which now exist. Organs in this latter state are not
strictly rudimentary, but they are tending in this direction.
Nascent organs, on the other hand, though not fully developed,
are of high service to their possessors, and are capable of further
development. Rudimentary organs are eminently variable ; and
this is partly intelligible, as they are useless, or nearly useless,
and consequently are no longer subjected to natural selection.
They often become wholly suppressed. When this occurs, they
are nevertheless liable to occasional reappearance through
reversion— a circumstance well worthy of attention.
The chief agents in causing organs to become rudimentary .
seem to have been disuse at that period of life when the organ
is chiefly used (and this is generally duriDg maturity), and also
inheritance at a corresponding period of life. The term
" disuse " does not relate merely to the lessened action of
muscles, but includes . a diminished flow of blood to a part or
organ, from being subjected to fewer alternations of pressure, or
from becoming in any way less habitually active. Rudiments,
however, may occur in one sex of those parts which are normally
present in the other sex; and such rudiments, as we shall
hereafter see, have often originated in a way distinct from those
here referred to. In some cases, organs have been reduced by
means of natural selection, from having become injurious to the
species under changed habits of life. The process of reduction
*s probably often aided through the two principles of compensa-
tion and economy of growth ; but the later stages of reduction,
after disuse has done all that can fairly be attributed to it, and
when the saving to be effected by the economy of growth would be
very small, 23 are difficult to understand. The final and complete
suppression of a part, already useless and much reduced in size,
in which case neither compensation nor economy can come into
play, is perhaps intelligible by the aid of the hypothesis of
pangenesis. But as the whole subject of rudimentary organs
has been discussed and illustrated in my former works/ 4 1 need
here say no more on this head.
Rudiments of various muscles have been observed in many
parts of the human body j 25 and not a few muscles, which are
23 Some good criticisms on this Zoolog. 1852, torn, xviii. p. 13) de-
subject have been given by Messrs. scribes and figures rudiments of
Muiie and Mivart, in ' Transact, what he calls the " muscle pedieux
Zoolog. Soc/ 1869, vol. vii. p. 92. de la main," which he says is some-
24 * Variation of Animals and times " infiniment petit." Another
Plants under Domestication/ vol. ii. muscle, called " le tibial post&ieur,"
pp. 317 and 397 See also * Origin is generally quite absent in the
$f Species,' 5th edit. p. 535. hand, but appears from time to time
24 For instance M. Ricnard (' An- in a more or less rudimentary con*
oales des Sciences Nat. 3rd series, dition.
Chap. I. Rudiments. 1 3
regularly present in some of the lower animals can occasionally
be detected in man in a greatly reduced condition. Every one
must have noticed the power which many animals, especially
horses, possess of moving or twitching their skin; and this is
effected by the panniculus carnosus. Eemnants of this muscle
in an efficient state are found in various parts of our bodies ; for
instance, the muscle on the forehead, by which the eyebrows are
raised. The platysma myoides, which is well developed on the
neck, belongs to this system. Prof. Turner, of Edinburgh, has
occasionally detected, as he informs me, muscular fasciculi in
five different situations, namely in the axillae, near the scapulae,
&c, all of which must be referred to the system of the panni-
cidus. He has also shewn 26 that the musculus sternalis or sternalis
brutorum, which is not an extension of the rectus abdominalis,
but is closely allied to the panniculus, occurred in the proportion
of about three per cent, in upwards of 600 bodies : he adds, that
this muscle affords "an excellent illustration of the statement
" that occasional and rudimentary structures are especially
" liable to variation in arrangement/'
Some few persons have the power of contracting the super-
ficial muscles on their scalps; and these muscles are in a
variable and partially rudimentary condition. M. A. de Candolle
has communicated to me a curious instance of the long-continued
persistence or inheritance of this power, as well as of its unusual
development. He knows a family, in which one member, the
present head of the family, could, when a youth, pitch several
heavy books from his head by the movement of the scalp alone ;
and he won wagers by performing this feat. His father, uncle,
grandfather, and his three children possess the same power to
the same unusual degree. This family became divided eight
generations ago into two branches; so that the head of the
above-mentipned branch is cousin in the seventh degree to the
head of the other branch. This distant cousin resides in
another part of France ; and on being asked whether he possessed
the same faculty, immediately exhibited his power. This case offers
a good' illustration how persistent may be the transmission of an
absolutely useless faculty, probably derived from our remote semi-
human progenitors ; since many monkeys have, and frequently
use the power, of largely moving their scalps up and down. 27
The extrinsic muscles which serve to move the external ear,
%nd the intrinsic muscles which move the different parts, are in a
rudimentary condition in man, and they all belong to the system
26 Prof. W. Turner, * Proc. Royal Emotions in Man and Animal*/
Soc. Edinburgh/ 1866-67, p. So. 1872, p, 144
87 See my .* Expression <-f the
f 4 The Descent of Man, Part 1
of the panniculus ; they are also variable in development, or at
least in function. I have seen one man who could draw the
whole ear forwards ; other men can draw it upwards ; another
who could draw it backwards; 28 and from what one of these
persons told me, it is probable that most of us, by often touching
our ears, and thus directing our attention towards them, could
recover some power of movement by repeated trials. The power
of erecting and directing the shell of the ears to the various
points of the compass, is no doubt of the highest service to
many animals, as they thus perceive the direction. of danger;
but I have never heard, on sufficient evidence, of a man who
possessed this power, the one which might be of use to him.
The whole external shell may be considered a rudiment, together
with the various folds and prominences (helix and anti-helix,
tragus and anti-tragus, &c.) which in the lower animals
strengthen and support the ear when erect, without adding
much to its weight. Some authors, however, suppose that the
cartilage of the shell serves to transmit vibrations to the
acoustic nerve; but Mr. Toynbee, 29 after collecting all the
known evidence on this head, concludes that the external shell
is of no distinct use. The ears of the chimpanzee and orang are
curiously like those of man, and the proper muscles are likewise
but very slightly developed. 30 I am also assured by the keepers in
the Zoological Gardens that these animals never move or erect
their ears ; so that they are in an equally rudimentary condition
with those of man, as far as function is concerned. Why these
animals, as well as the progenitors of man, should have lost the
power of erecting their ears, we cannot say. It may be, though
I am not satisfied with this view, that owing to their arboreal
habits and great strength they were but little exposed to danger,
and so during a lengthened period moved their ears but little,
and thus gradually lost the power of moving them. This
would be a parallel case with that of those large and heavy
birds, which, from inhabiting oceanic islands, have not been
exposed to the attacks of beasts of prey, and have consequently
lost the power of using their wings for flight. The inability to
move the ears in man and several apes is, however, partly eoni-
j^ensated by the freedom with which they can move the head in
28 Canestrini quotes Hyrtl. (' An- lately been experimenting on the
nuario della Soc. dei Naturalisti, function of the shell of the ear,
Modena, 1867, p. 97) to the same and has come to nearly the same
effect conclusion as that given here.
29 * The Diseases of the Ear,* by so Prof. A. Macalister, ' Annals
J. Toynbee, F.R.S., 1860, p. 12. and Mag. of Nat. History,' vol vii^
A distinguished physiologist, Prof. 1871, p. 342.
Prayer, informs me that he had
CHAt\ I.
Rudiments.
IS
a horizontal plane, so as to catch sounds from all directions. It
lias been asserted that the ear of man alone possesses a lobule ;
but '* a rudiment of it is found in the gorilla;" 31 and, as I hear
from Prof. Preyer, it is not rarely absent in the negro.
---"The celebrated sculptor, Mr. Woolner, informs me of one little
peculiarity in the external ear, which he has often observed both
in men and women, and of which he perceived the full signi-
ficance. His attention was first called to the subject whilst at
work on his figure of Puck, to which he had given pointed ears.
He was thus led to examine the ears of various monkeys, and sub-
sequently more carefully those of man. The peculiarity consists
in a little blunt point, projecting from the inwardly folded margin,
or helix. When present, it is developed at birth, and, according
to Prof. Ludwig Meyer, more frequently in man than in woman.
Mr. Woolner made an exact model of one such case, and sent me
the accompanying drawing. (Pig. 2.)
These points not only project inwards
towards the centre of the ear, but often
a little outwards from its plane, so as
to be visible when the head is viewed
from directly in front or behind. They
are variable in size, and somewhat in
position, standing either a little higher
or lower; and they sometimes occur
on one ear and not on the other. They
are not confined to mankind, for I ob-
served a case in one of the spider-
monkeys (Ateles beehehuth) in our
Zoological Gardens; and Dr. E. Ray
Lankester informs me of another case
in a chimpanzee in the gardens at
Hamburg. The helix obviously con-
sists of the extreme margin of the ear folded inwards; and
this folding appears to be in some manner connected with the
whole external ear being permanently pressed backwards. In
many monkeys, which do not stand high in the order, as baboons
and some species of macacus, 32 the upper portion of the ear is
slightly pointed, and the margin is not at all folded inwards;
but if the margin were to be thus folded, a slight point would
necessarily project inwards towards the centre, and probably a
little outwards from the plane of the ear ; and this I believe to
Fig 2. Human Ear. modelled
and drawn by Mr. Woolner.
a. The projecting point.
31 Mr. St. George Mivart, * Ele-
mentary Anatomy,' 1873, p. 396.
32 See also some remarks, and
the drawings of the ears of the
Lemuroidea, in Messrs. Murie and
Mivart's excellent paper in 'Tran-
sact. Zoolog. Soc.' vol. vii. 1869, pp
6 and 9a
r 6 Tlie Descent of Man. Part I.
be their origin in many cases. On the other hand, Prof. L. Meyer,
in an able paper recently published, 83 maintains that the whole
case is one of mere variability ; and that the projections are not
real ones, but are due to the internal cartilage on each side of
the points not having been fully developed. I am quite ready
to admit that this is the correct explanation in many instances,
as in those figured by Prof. Meyer, in which there are several
minute points, or the whole margin is sinuous. I have myself
seen, through the kindness of Dr. L. Down, the ear of a micro-
cephalous idiot, on which there is a projection on the outsido
of the helix, and not on the inward folded edge, so that this
point can have no relation to a former apex of the ear. Never-
theless in some cases, my original view, that the points
are vestiges of the tips of formerly erect and pointed ears,
still seems to me probable. I think so from the frequency ot
their occurrence, and from the general correspondence in
position with that of the tip of a pointed ear. In one case, ot
which a photograph has been sent me, the projection is so large,
that supposing, in accordance with Prof. Meyer's view, the ear
to be made perfect by the equal development of the cartilage
throughout the whole extent of the margin, it would have
covered fully one-third of the whole ear. Two cases have been
communicated to me, one in North America, and the other in
England, in which the upper margin is not at all folded inwards,
but is pointed, so that it closely resembles the pointed ear of an
ordinary quadruped in outline. In one of these cases, which was
that of a young cliild, the father compared the ear with the
drawing which I have given 34 of the ear of a monkey, the
Cynopithecus niger, and says that their outlines are closely
similar. If, in these two cases, the margin had been folded
inwards in the normal manner, an inward projection must have
been formed. I may add that in two other cases the outline still
remains somewhat pointed, although the margin of the upper
part of the ear is normally folded inwards — in one of them,
however, very narrowly. The following woodcut (No. 3) is an
accurate copy of a photograph of the foetus of an oraug (kindly
sent me by Dr. Nitsche), in which it may be seen how different the
pointed outline of the ear is at this period from its adult condition,
when it bears a close general resemblance to that of man. It is
evident that the folding over of the tip of such an ear, unless it
changed greatly during its further development, would give riso
to a point projecting inwards. On the whole, it still seems to
M UeberdasDarwin'scheSpitzohr, M 'The Expression of the Em<*
Archiv ftir Path. Anat. und Phys. tions/ p. 136.
1871, p. 485.
Chap. I.
Rudiments,
17
me probable that the points in question are in some cases, both
frx man and apes, vestiges of a former condition.
IJIg. 3. Foetus of an Orang. Exact copy of a photograph, shewing the form of
the ear at this early age.
The nictitating membrane, or third eyelid, with its accessory
muscles and other structures, is especially well developed in
birds, and is of much functional importance to them, as it can
be rapidly drawn across the whole eye-ball. It is found in some
reptiles and amphibians, and in certain fishes, as in sharks. It
is fairly well developed in the two lower divisions of the mam-
malian series, namely, in the monotremata and marsupials, and
in some few of the higher mammals,- as in the walrus. But in
man, the quadrumana, and most other mammals, it exists, as is
admitted by all anatomists, as a mere rudiment, called the
semilunar fold. 88 <
The sense of smell is of the highest importance to the greater
number of mammals— to some, as the ruminants, in warning
them of danger; to others, as the carnivora, in finding their
prey; to others, again, as the wild boar, for both purposes
combined. But the sense of smell is of extremely slight service,
if any, even to the dark coloured races of men, in whom it is
85 Miiller's * Elements of Physi-
ology,' Eng. translat., 1842, vol. ii.
p. 1117. Owen, ' Anatomy of Verte-
brates/ vol. iii. p. 260; ibid, on
the Walrus, 'Proc. Zoolog. Soc'
November 8th, 1854. See also R.
Knox, 'Great Artists and Anato-
mists,' p. 106. This rudiment ap-
parently is somewhat larger in
Negroes and Australians than in
Europeans, see Carl Vogt, ' Lectures
on Man/ Eng. translat. p. 129.
C
1 8 The Descent of Man. Part L
much more highly developed than in the white and civilised
races. 86 Nevertheless it does not warn them of danger, nor guida
them to their food ; nor does it prevent the Esquimaux from
sleeping in the most fetid atmosphere, nor many savages from
eating half-putrid meat. In Europeans the power differs greatly
in different individuals, as I am assured by an eminent naturalist
who possesses this sense highly developed, and who has at-
tended to the subject. Those who believe in the principle
of gradual evolution, will not readily admit that the sense of
smell in its present state was originally acquired by man, as
he now exists. He inherits the power in an enfeebled and
so far rudimentary condition, from some early progenitor, to
whom it was highly serviceable, and by whom it was con-
tinually used. In those animals which have this sense highly
developed, such as dogs and horses, the recollection of persons
and of places is strongly associated with their odour ; and we can
thus perhaps understand how it is, as Dr. Maudsley has truly
remarked, 37 that the sense of smell in man " is singularly effective
" in recalling vividly the ideas and images of forgotten scenes
" and places."
Man differs conspicuously from all the other Primates in being
almost naked. But a few short straggling hairs are found over
the greater part of the body in the man, and fine down on that
of the woman. The different races differ much in hairiness ; and
in the individuals of the same race the hairs are highly variable,
not only in abundance, but likewise in position : thus in some
Europeans the shoulders are quite naked, whilst in others they
bear thick tufts of hair. 38 There can be little doubt that the
hairs thus scattered over the body are the rudiments of the
uniform hairy coat of the lower animals. This view is rendered
all the more probable, as it is known that fine, short, and pale-
coloured hairs on the limbs and other parts of the body, occasion-
38 The account given by Humboldt olfactory region, as well as of the
of the power of smell possessed by skin of the body. I have, therefore,
the natives of South America is well spoken in the text of the dark-
known, and has been confirmed by coloured races having a finer sense
others. M. Houzeau (' Etudes sur of smell than the white races. See
les Facultes Mentales/ &c, torn. i. his paper, * Medico-Chirurgical Tran-
1872, p. 91) asserts that he re- sactions,' London, vol. liii., 1870,
peatedly made experiments, and p. 276.
proved that Negroes and Indians 37 * The Physiology and Pathology
could recognise persons in the dark of Mind,' 2nd edit. 1868, p. 134.
by their odour. Dr. W. Ogle has & Eschricht, Ueber die Richtung
made some curious observations on der Haare am menschlichen Korper,
the connection between the power 'Miiller's ArchivfiirAnat.undPhys.*
of smell and th3 colouring matter 1837, s. 47. I shall often hav« fca
of the mucous membrane of the refer to this very curious papen
Chap. I. Rudiments. 19
ally become developed into "thickset, long, and rather coarse
*' dark hairs," when abnormally nourished near old-standing
inflamed surfaces. 39
I am informed by Sir James Paget that often several members
of a family have a few hairs in their eyebrows much longer than
the others; so that even this slight peculiarity seems to be
inherited. These hairs, too, seem to have their representatives ;
for in the chimpanzee, and in certain species of Macacus, there
are scattered hairs of considerable length rising from the naked
ekin above the eyes, and corresponding to our eyebrows ; similar
long hairs project from the hairy covering of the superciliary
ridges in some baboons.
The fine wool-like hair, or so-called lanugo, with which the
human foetus during the sixth month is thickly covered, offers a
more curious case. It is first developed, during the fifth month,
on the eyebrows and face, and especially round the mouth,
where it is much longer than that on the head. A moustache
of this kind was observed by Eschricht 40 on a female foetus ; but
this is not so surprising a circumstance as it may at first appear,
for the two sexes generally resemble each other in all external
characters during an early period of growth. The direction and
arrangement of the hairs on all parts of the fcetal body are the
same as in the adult, but are subject to much variability. The
whole surface, including even the forehead and ears, is thus
thickly clothed ; but it is a significant fact that the palms of the
hands and the soles of the feet are quite naked, like the inferior
surfaces of all four extremities in most of the lower animals. As
this can hardly be an accidental coincidence, the woolly cover-
ing of the foetus probably represents the first permanent coat of
hair in those mammals which are born hairy. Three or four
cases have been recorded of persons born with their whole bodies
and faces thickly covered with fine long hairs ; and this strange
condition is strongly inherited, and is correlated with an abnor-
mal condition of the teeth. 41 Prof. Alex. Brandt informs me that
he has compared the hair from the face of a man thus charac-
T erised, aged thirty-five, with the lanugo of a foetus, and finds it
quite similar in texture ; therefore, as he remarks, the case may
he attributed to an arrest of development in the hair, together
with its continued growth. Many delicate children, as I have
*• Paget, 'Lectures on Surgical has recently sent me an additional
Pathology/ 1853, vol. i. f.". 71. case of a father and son, born in
40 Eschricht, ibid. s. 40, 47. * Russia, with these peculiarities. I
41 See my * Variation of Animals have received drawings of both frcm
and Plants titder Domestication,' Paris.
voL ii. p. 327. Prof. Alex. Brandt
20 Tfie Descent of Man. Part I.
been assured by a surgeon to a hospital for children, have their
backs covered by rather long silky hairs ; and such cases pro-
bably come under the same head.
It appears as if the posterior molar or wisdom-teeth were
tending to become rudimentary in the more civilised races of
man. These teeth are rather smaller than the other molars, as
is likewise the case with the corresponding teeth in the chim-
panzee and orang; and they have only two separate fangs.
They do not cut through the gums till about the seventeenth
year, and I have been assured that they are much more liable to
decay, and are earlier lost than the other teeth ; but this is denied
by some eminent dentists. They are also much more liable to
vary, both in structure and in the period of their development,
than the other teeth. 4 * In the Melanian races, on the other
hand, the wisdom-teeth are usually furnished with three
separate fangs, and are generally sound ; they also differ from
the other molars in size, less than in the Caucasian races. 43
Prof. Schaaifhausen accounts for this difference between the
races by " the posterior dental portion of the jaw being always
" shortened" in those that are civilised, 44 and this shortening may,
I presume, be attributed to civilised men habitually feeding on
soft, cooked food, and thus using their jaws less. I am informed
by Mr. Brace that it is becoming quite a common practice in the
United States to remove some of the molar teeth of children, as
the jaw does not grow large enough for the perfect development
of the normal number. 45
With respect to the alimentary canal, I have met with an
account of only a single rudiment, namely the vermiform append-
age of the cseeum. The csecum is a branch or diverticulum of
the intestine, ending in a cul-de-sac, and is extremely long in
many of the lower vegetable-feeding mammals. In the marsupial
koala it is actually more than thrice as long as the whole body. 48
It is sometimes produced into a long gradually-tapering point.
and is sometimes constricted in parts. It appears as if, in con-
sequence of changed diet or habits, the csecum had become much
42 Dr. Webb, * Teeth in Man and from Florence, that he has lately
the Anthropoid Apes,' as quoted by been studying the last molar teeth
Dr. C. Carter Blake in « Anthropo- in the different races of man, and
logical Revkw,' July 1867, p. 299. has come to the same conclusion as
43 Owen, * Anatomy of Verte- that given in my text, viz., that in
brates,' vol. iii. pp. 320, 321, an! the higher or civilised races they
325- are on the road towards atrophy or
44 * On the Primitive Form of the elimination.
Skull,' Eng. translat. in ' Anthropo- «« Owen, * Anatomy of Verte-
logical Review,' Oct. 1868, p. 426. brates/ vol. iii. pp. 416, 434, 441.
46 Prof. Montegazxa writes to mo
i,1iai» l. Rudiments. 21
shortened in various animals, the vermiform appendage being
left as a rudiment of the shortened part. That this appendage
is a rudiment, we may infer from its small size, and from the
evidence which Prof. Canestrini 47 has collected of its^ variability
in man. It is occasionally quite abseot, or again is largely
developed. The passage is sometimes completely closed for half
or two-thirds of its length, with the terminal part consisting of
a flattened solid expansion. In the orangthis appendage is long
and convoluted: in man it arises from the end of the short
caxmm, and is commonly from four to five inches in length,
being only about the third of an inch in diameter. Not only is
it useless, but it is sometimes the cause of death, of which fact
I have lately heard two instances: this is due to small hard
bodies, such as seeds, entering the passage, and causing inflam-
mation. 48
In some of the lower Quadrumana, in the Lemuridae and
Carnivora, as well as in many marsupials, there is a passage near
the lower end of the humerus, called the supra-condyloid fora-
men, through which the great nerve of the fore limb and often
the great artery pass. Now in the humerus of man, there is
generally a trace of this passage, which is sometimes fairly well
developed, being formed by a depending hook-like process of
bone, completed by a band of ligament. Dr. Struthers, 49 who has
closely attended to the subject, has now shewn that this
peculiarity is sometimes inherited, as it has occurred in a father,
and in no less than four out of his seven children. When pre-
sent, the great nerve invariably passes through it; and this
clearly indicates that it is the homologue and rudiment of the
supra-condyloid foramen of the lower animals. Prof. Turner
estimates, as he informs me, that it occurs in about one per cent,
of recent skeletons. But if the occasional development of this
structure in man is, as seems probable, due to reversion, it is a
return to a very ancient state of things, because in the higher
Quadrumana it is absent.
There is another foramen or perforation in the humerus,,
47 <Annuario della Soc. d. Nat/ Feb. 15, 1873, and another im-
Modena, 1867, p. 94. ' portant paper, ibid., Jan. 24, 1863,
48 M. C. Martins (" De TUnite' p. 83. Dr. Knox, as I am informed,
Organique," in * Revue des Deux was the first anatomist who drew
Mondes,' June 15, 1862, p. 16), and attention to this peculiar structure
H'ackel (* Generelle Morphologic,' in man ; see his * Great Artists and
B. iL s. 278), have both remarked Anatomists,* p. 63. See also an im-
on the singular fact of this rudi- portant memoir on this process by
ment sometimes causing death. Dr. Gruber, in the * Bulletin de
** With respect to inheritance, l'Acad. Imp. de St. Peter-bourg,
Gee
Br. Struthers ua the * Lancet/ tonr.. x:i. 1867, p. 448.
22 The Descent of Man, t*AHT I
occasionally present in man, which may be called the inter-
condyloid. This occurs, but not constantly, in various anthro-
poid and other apes, 50 and likewise in many of the lower animals.
It is remarkable that this perforation seems to have been present
in man much more frequently during ancient times than
recently. Mr. Busk 51 has collected the following evidence on
this head : Prof. Broca " noticed the perforation in four and a
" half per cent, of the arm-bones collected in the ' Cimetiere du
" Sud/ at Paris ; and in the Grotto of Orrony, the contents of
"which are referred to the Bronze period, as many as eight
" humeri out of thirty-two were perforated ; but this extraordi-
" nary proportion, he thinks, might be due to the cavern having
" been a sort of ' family vault.' Again, M. Dupont found thirty
" per cent, of perforated bones in the caves of the Valley of the
" Lesse, belonging to the Eeindeer period ; whilst M. Leguay, in
" a sort of dolmen at Argenteuil, observed twenty-five per cent,
"to be perforated; and M. Pruner-Bey found twenty-six per
" cent, in the same condition in bones from Vaureal. Nor should
" it be left unnoticed that M. Pruner-Bey states that this con-
" dition is common in Guanche skeletons." It is an interesting
fact that ancient races, in this and several other cases, more
frequently present structures which resemble those of the lower
animals than do the modern. One chief cause seems to be that
the ancient races stand somewhat nearer in the long line of
descent to their remote animal-like progenitors.
In man, the os coccyx, together with certain other vertebras
hereafter to be described, though functionless as a tail, plainly
represent this part in other vertebrate animals. At an early
embryonic period it is free, and projects beyond the lower
extremities ; as may be seen in the drawing (Fig. 1.) of a human
embryo. Even after birth it has been known, in certain rare
and anomalous cases, 52 to form a small external rudiment of a
tail. The os coccyx is short, usually including only four
vertebrae, all anchylosed together: and these are in a rudi*
50 Mr. St. George Mivart, * Trans- 53 Quatrefages has lately collected
act. Phil. Soc.' 1867, p. 310. the evidence on this subject. * Revue
41 "On the Caves of Gibraltar," des Cours Seientifiques/ 1867-1868,
' Transact. Internat. Congress of p. 625. In 1840 Fleischmann ex-
Prehist. Arch/ Third Session, 1869, hibited a human fetus bearing a
p. 159. Prof. Wyman has lately free tail, which, as is not always the
thewn (Fourth Annual Report, Pea- case, incladed vertebral bodies; and
body Museum, 1871, p. 20), that this this tail was critically examined by
perforation is present in thirty-one the many anatomists present at the
per cent, of some human remains meeting of naturalists at Erlangen
from ancient mounds in the Western (see Marshall in Mederlandischen
United States, and in Florida. It Archvr liir Zoologie, December 1871 >
frequently occurs in the negro.
Cha*. I. Rudiments, 23
mentary condition, for they consist, with the exception of the
basal one, of the centrum alone. 53 They are furnished with
some small muscles; one of which, as I am informed by Prof.
Turner, has been expressly described by Theile as a rudimentary
repetition of the extensor of the tail, a muscle which is so
largely developed in many mammals.
The spinal cord in man extends only as far downwards as the
last dorsal or first lumbar vertebra; but a thread-like struc-
ture (the filum terminate) runs down the axis of the sacral part
of the spinal canal, and even along the back of the coccygeal
bones. The upper part of this filament, as Prof. Turner
informs, me, is undoubtedly homologous with the spinal cord •
but the lower part apparently consists merely of the pia mater,
or vascular investing membrane. Even in this case the os
coccyx may be said to possess a vestige of so important a
structure as the spinal cord, though no longer enclosed within
a bony canal. The following fact, for which I am also in-
debted to Prof. Turner, shews how closely the os coccyx corre-
sponds with the true tail in the lower animals : Luschka has
recently discovered at the extremity of the coccygeal bones a
very peculiar convoluted body, which is continuous with the
middle sacral artery ; and this discovery led Krause and Meyer
to examine the tail of a monkey (Macacus), and of a cat, in both
of which they found a similarly convoluted body, though not at
the extremity.
The reproductive system offers various rudimentary struc-
tures; but these differ in one important respect from the
foregoing cases. Here we are not concerned with the vestige of
a part which does not belong to the species in an efficient state,
but with a part efficient in the one sex, and represented in the
other by a mere rudiment. Nevertheless, the occurrence of
such rudiments is as difficult to explain, on the belief of the
separate creation of each species, as in the foregoing cases.
Hereafter I shall have to recur to these rudiments, and shall
shew that their presence generally depends merely on inheri-
tance, that is, on parts acquired by one sex having been
partially transmitted to the other. I will in this place only give
some instances of such rudiments. It is well known that in the
males of all mammals, including man, rudimentary mammae
exist. These in several instances have become well developed,
and have yielded a copious supply of milk. Their essential
identity in the two sexes is likewise shewn by their occasional
sympathetic enlargement in both during an attack of the
a8 Owes, < On the Nature of Umbs t y 1849, p. 114.
24 The Descent of Man, Part j
measles. The vesicula prostatica, which has been observed in
many male mammals, is now universally acknowledged to be
the homologue of the female uterus, together with the con-
nected passage. It is impossible to read Leuckart's able
description of this organ, and his reasoning, without admitting
the justness of his conclusion. This is especially clear in the
case of those mammals in which the true female uterus
bifurcates, for in the males of these the vesicula likewise
bifurcates. 64 Some other rudimentary structures belonging to
the reproductive system might have been here adduced. 55
The bearing of the three great classes of facts now given is
unmistakeable. But it would be superfluous fully to recapitulate
the line of argument given in detail in my ' Origin of Species,'
The homological construction of the whole frame in the members
of the same class is intelligible, if we admit their descent from
a common progenitor, together with their subsequent adaptation
to diversified conditions. On any other view, the similarity of
pattern between the hand of a man or monkey, the foot
horse, the flipper of a seal, the wing of a bat, &c, is utterly
inexplicable. 56 It is no scientific explanation to assert that they
have all been formed on the same ideal plan. With respect to
development, we can clearly understand, on the principle of
54 Leuckart, in Todd's * Cyclop, words) a mere metaphysical prin-
o£ Anat/ 1849-52, vol. iv. p. 1415. ciple, namely, the preservation "in
In man this organ is only from " its integrity of the mammalian
three to six lines in length, but, " nature of the animal." In only a
like so many other rudimentary few cases does he discuss rudiments,
parts, it is variable in development and then only those parts which are
as well as in other characters. partially rudimentary, such as the
55 See, on this subject, Owen, little hoofs of the pig and ox, which
* Anatomy of Vertebrates/ vol. iii. do not touch the ground ; these he
pp. 675, 676, 706. shews clearly to be of service to the
56 Prof. Bianconi, in a recently animal. It is unfortunate that he
published work, illustrated by ad- did not consider such cases as the
mirable engravings ('La Theorie minute teeth, which never cut
Darwinienne et la creation dite in- through the jaw in the ox, or the
dependante,' 1874), endeavours to mammae of male quadrupeds, or the
show that homological structures, in wings of certain beetles, existing
the above and other cases, can be under the soldered wing-covers, or
fully explained on mechanical prin- the vestiges of the pistil and stamens
ciples, in accordance with their uses, in various flowers, and many other
No one has shewn so well, how ad- such cases. Although I greatly
mirably such structures are adapted admire Prof. Bianconi's work, yet
for their final purpose ; and this the belief now held by most natural-
adaptation can, as I believe, be ists seems to me left unshaken,
explained through natural selection, that homological structures are in-
In considering the wing of a bat, he explicable on the principle of mere
brings forward (p. 218) what appears adaptation.
to me (to use Auguste Comte's
Chap. J. Rudiments, 25
variations supervening a* a rafcher late embryonic period, and
being inherited at a corresponding period, how it is that the
embryos of wonderfully different forms should still retain, mors
or less perfectly, the structure of their common progenitor.
No other explanation has ever been given of the marvellous fact
that the embryos of a man, dog, seal, bat, reptile, &c, can at first
hardly be distinguished from each other. In order to understand
the existence of rudimentary organs, we have only to suppose
that a former progenitor possessed the parts in question in a
perfect state, and that under changed habits of life they became
greatly reduced, either from simple disuse, or through the natural
selection of those individuals which were least encumbered with
a superfluous part, aided by the other means previously in-
dicated.
Thus we can understand how it has come to pass that man and
all other vertebrate animals have been constructed on the same
general model, why they pass through the same early stages ot
development, and why they retain certain rudiments in common.
Consequently we ought frankly to admit their community of
descent; to take any other view, is to admit that our own
structure, and that of all the animals around us, is a mere snare
laid to entrap our judgment. This conclusion is greatly
strengthened, if we look to the members of the whole animal
series, and consider the evidence derived from their affinities
or classification, their geographical distribution and geolo-
gical succession. It is only our natural prejudice, and that
arrogance which made our forefathers declare that they were
descended from demi-gods, which leads us to demur to this
conclusion. But the time will before long come, when it will be
thought wonderful that naturalists, who were well acquainted
with the comparative structure and development of man, and
other mammals, should have believed that each was the work
of a separate act of creation.
26 The Descent of Man, Pax* 1
CHAPTEB a.
Ok the Manner of Development of Man from some
Lower Form.
Variability of body and mind in man — Inheritance — Causes of variability
— Laws of variation tne same in man as in the lower animals — Direct
action of the conditions of life — Effects of the increased use and disuse
of parts — Arrested development — Reversion — Correlated variation —
Rate of increase — Checks to increase — Natural selection — Man the most
dominant animal in the world — Importance of his corporeal structure —
The causes which have led to his becoming erect — Consequent changes
of structure — Decrease in size of the canine teethe — Increased size and
altered shape of the skull — Nakedness — Absence of a tail — Defenceless
condition of man.
It is manifest that man is now subject to much variability.
No two individuals of the same race are quite alike. We may
compare millions of faces, and each will be distinct. There is
an equally great amount of diversity in the proportions and
dimensions of the various parts of the body ; the length of the
legs being one of the most variable points. 1 Although in some
quarters of the world an elongated skull, and in other quarters
a short skull prevails, yet there is great diversity of shape even
within the limits of the same race, as with the aborigines of
America and South Australia — the latter a race " probably as
" pure and homogeneous in blood, customs, and language as any
** in existence " — and even with the inhabitants of so confined
an area as the Sandwich Islands. 2 An eminent dentist assures
me that there is nearly as much diversity in the teeth as in the
features. The chief arteries so frequently run in abnormal
courses, that it has been found useful for surgical purposes to
calculate from 1040 corpses how often each course prevails. 3
The muscles are eminently variable: thus those of the foot
were found by Prof. Turner 4 not to be strictly alike in any two
out of fifty bodies ; and in some the deviations were considerable,
1 'Investigations in Military and Huxley, in LyelPs 'Antiquity of
Anthropolog. Statistics of American Man/ 1863, p. 87. On the Sand-
Soldiers/ by B. A. Gould, 1869, p. wich Islanders, Prof. J. Wyman,
256. 'Observations on Crania,' Boston ;
2 With respect to the « Cranial 1868, p. 18.
forms of the American aborigines,' , * * Anatomy of the Arteries," by
Bee Dr. Ait ken Meigs in ' Proc. R. Quain. Preface, vol. i. 1844.
Acad. Nat. Sci.' Philadelphia, May, 4 'Transact. Royal Soc. Ediiy
1868. On the Australians, see frcrgh,' vol. xxiv. pp. 175, 180.
Uha*. II. Manner of Development 27
Ee adds, that the power of performing the appropriate move-
ments must have been modified in accordance with the several
deviations. Mr. J. Wood has recorded 5 the occurrence of 295
muscular variations in thirty-six subjects, and in another set of
the same number no less than 558 variations, those occurring on
both sides of the body being only reckoned as one. In the last
set, not one body out of the thirty-six was " found totally
«< wanting in departures from the standard descriptions of the
" muscular system given in anatpmical text books." A single
body presented the extraordinary number of twenty-five distinct
abnormalities. The same muscle sometimes varies in many
ways: thus Prof. Macalister describes 6 no less than twenty
distinct variations in the palmaris accessorius.
The famous old anatomist, Wolff, 7 insists that the internal
viscera are more variable than the external parts: Nulla parti-
cular est qua non aliter et aliter in aliis se habeat liominibus. He
has even written a treatise on the choice of typical examples of •
the viscera for representation. A discussion on the beau-ideal
of the liver, lungs, kidneys, &c, as of the human face divine,
Bounds strange in our ears.
The variability or diversity of the mental faculties in men of
the same race, not to mention the greater differences between
the men of distinct races, is so notorious that not a word need
here be said. So it is with the lower animals. All who have
had charge of menageries admit this fact, and we see it plainly
in our dogs and other domestic animals. Brehm especially
insists that each individual monkey of those which he kept tame
in Africa had its own peculiar disposition and temper: he men-
tions one baboon remarkable for its high intelligence ; and the
keepers in the Zoological Gardens pointed out to me a monkey,
belonging to the New World division, equally remarkable for
intelligence. Eengger, also, insists on the diversity in the
various mental characters of the monkeys of the same species
which he kept in Paraguay; and this diversity, as he adds, is
partly innate, and partly the result of the maimer in which they
have been treated or educated. 8
I have elsewhere 9 so fully discussed the subject of Inheritance,
that I need here add hardly anything. A greater number of
5 'Pioc. Royal Soc* 1867, p. 8 Biehm, * Thierleben/ B. i. a.
544 ; also 1868, pp. 483, 524. There 58, 87. Rengger, ' Saugethiere toe
is a previous paoer, 1866, p. 229. Paraguay/ s. 57.
6 ' Proc. R. Irish Academy,' vol. • * Variation of Animals and
x. 1868, p! 141. Fiants under Domestication,' vol
: 'Act. Acad. St. Petersburg/ ii. chap. sa.
1778, part ii. p. 217
28 The Descent of Man* Tart 1,
facts have been collected with respect to th« transmission of the
most trifling, as well as of the most important characters in
man, than in any of the lower animals; though the facts are
copious enough with respect to the latter. So in regard to
mental qualities, their transmission is manifest in our dogs,
horses, and other domestic animals. Besides special tastes and
habits, general intelligence, courage, bad and good temper, &c,
are certainly transmitted. With man we see similar facts in
almost every family; and we now know, through the admirable
labours of Mr. Galton, 10 that genius which implies a wonderfully
complex combination of high faculties, tends to be inherited;
and, on the other hand, it is too certain that insanity and deteri-
orated mental powers likewise run in families.
With respect to the causes of variability, we are in all cases
very ignorant; but we can see that in man as in the lower
animals, they stand in some relation to the conditions to which
• each species has been exposed, during several generations.
Domesticated animals vary more than those in a state of nature ;
and this is apparently due to the diversified and changing nature
of the conditions to which they have been subjected. In this
respect the different races of man resemble domesticated animals,
and so do the individuals of the same race, when inhabiting a
very wide area, like that of America. We see the influence of
diversified conditions in the more civilised nations; for the
members belonging to different grades of rank, and following
different occupations, present a greater range of character than
do the members of barbarous nations. But the uniformity of
savages has often been exaggerated, and in some cases can hardly
be said to exist. 11 It is, nevertheless, an error to speak of man,
even if we look only to the conditions to which he has been
exposed, as " far more domesticated " 12 than any other animal.
Some savage races, such as the Australians, are not exposed to
more diversified conditions than are many species which have
a wide range. In another and much more important respect,
man differs widely from any strictly domesticated animal ; for
his breeding has never long been controlled, either by methodical
or unconscious selection. No race or body of men has been so
10 * Hewditwy Genius : an In- " man had an oval visage with fine
quiry into :t3 Laws and Conse- " features, and another was quite
quences/ 1869. " Mongolian in breadth and pro-
11 Mr. Bates remarks (' The Natu- ** minence of cheek, spread of nos-
ralist on the Amazons/ 1863, vol. ii. " trils, and obliquity of eyes."
p. 159), with respect to the Indians 12 Blumenbach, 'Treatises on An-
of the same South American tribe, thropolog.* Eng. translal., 18 ?5, p.
a to two of them were at all similar 205.
u in the shape of the head j on?
Chap. II. Manner of Development 29
completely subjugated by other men, as that certain individuals
should be preserved, and thus unconsciously selected, from some-
how excelling in utility to their masters. Nor have certain
male and female individuals been intentionally picked out and
matched, except in the well-known case of the Prussian grena-
diers ; and in this case man obeyed, as might have been ex-
pected, the law of methodical selection ; for it is asserted that
many tall men were reared in the villages inhabited by the
grenadiers and their tall wives. In Sparta, also, a form of selec-
tion was followed, for it was enacted that all children should be
examined shortly after birth; the well-formed and vigorous
being preserved, the others left to perish. 13
If we consider all the races of man as forming a single species,
his range is enormous ; but some separate races, as the Americans
and Polynesians, have very wide ranges. It is a well-known
law that widely-ranging species are much more variable than
species with restricted ranges ; and the variability of man may
with more truth be compared with that of widely-ranging species,
than with that of domesticated animals.
Not only does variability appear to bo induced in man and
the lower animals by the same general causes, but in both the
same parts of the body are affected in a closely analogous
manner. This, has been proved in such full detail by Godron and
13 Mitford's ' History of Greece/ vigour of their children. The Gre-
vol. i. p. 282. It appears also from cian poet, Theognis, who lived 550
a passage in Xenophon's ' Memora- B.C., clearly saw how important
bilia,' B. ii. 4 (to which my atten- selection, if carefully applied, would
tion has been called by the Rev. be for the improvement of mankind.
J. N. Hoare), that it was a well He saw, likewise, that wealth often
recognised principle with the Greeks, checks the proper action of sezua]
that men ought to select their wives selection. He thus writes :
with a view to the health and
" With kine and horses, Kurnus ! we proceed
By reasonable rules, and choose a breed
For profit and increase, at any price ;
Of a sound stock, without defect or vice.
But, in the daily matches that we make,
The price is everything : for money's sake,
Men marry : women are in marriage given
The churl or ruffian, that in wealth has thriven,
May match his offspring with the proudest race :
Thus everything is mix'd, noble and base !
If then in outward manner, form, and mind,
You find us a degraded, motley kind,
Wonder no more, my friend I the cause is plain,
And to lament the consequence is vain.'*
(The Weeks of J. Hookham Frere, vol. ii. 1872, p. 334.)
30 The Descent of Man. Tax? L
Quatrefages, that I need here only refer to their works. 1,1 Mon-
strosities, which graduate into slight variations, are likewise so
similar in man and the lower animals, that the same classification
and the same terms can be used for both, as has been shewn by
Isidore Geoffroy St.-Hilaire. 16 In my work on the variation of
domestic animals, I have attempted to arrange in a rude fashion
the laws of variation under the following heads : — The direct and
definite action of changed conditions, as exhibited by all or nearly
all the individuals of the same species, varying in the same manner
Under the same circumstances. The effects of the long-continued
use or disuse of parts. The cohesion of homologous parts. The
variability of multiple parts. Compensation of growth ; but of
this law I have found no good instance in the case of man. The
effects of the mechanical pressure of one part on another ; as of
the pelvis on the cranium of the infant in the womb. Arrests of
development, leading to the diminution or suppression of parts.
The reappearance of long-lost characters through reversion.
And lastly, correlated variation. All these so-called laws apply
equally to man and the lower animals ; and most of them even
to plants. It would be superfluous here to discuss all of them ; 10
but several are so important, that they must be treated at con-
siderable length.
The direct and definite action of changed conditions. — This is a
most perplexing subject. It cannot be denied that changed con-
ditions produce some, and occasionally a considerable effect, on
organisms of all kinds ; and it seems at first probable that if
sufficient time were allowed this would be the invariable result.
But I have failed to obtain clear evidence in favour of this con-
clusion ; and valid reasons may be urged on the other side, at
least as far as the innumerable structures are concerned, which
are adapted for special ends. There can, however, be no doubt
that changed conditions induce an almost indefinite amount of
fluctuating variability, by which the whole organisation is rend-
ered in some degree plastic.
In the United States, above 1,000,000 soldiers, who served in
the late war, were measured, and the States in which they were
14 Godron, *De l'Espece,' 1859, 16 I have fully discussed these
tcm. ii. livre 3. Quatrefages, * Unite laws in my * Variation of Animals
de l'Espece Humaine,' 1861. Also and Plants under Domestication,'
Lectures on Anthropology, given in vol. ii. chap. xxii. and xxiii. M. J.
the *■ Revue des Cours Scientifiques,' P. Durand has lately (1868) pub-
1866-1868. lished a valuable essay * De l'ln-
15 * Hist. Ge*n. a> Part, des Ano- fluence des Milieux,' &c. He lays
malies de rOrgamsation,' in three much stress, in the case of plar is, on
volumes, torn. i. 1832. the nature of the soil.
Chap. II. Manner of Development 3 1
born and reared were recorded. 17 From this astonishing number
of observations it is proved that local influences of some kind
act directly on stature ; and we further learn that " the State
" where the physical growth has in great measure taken place,
" and the State of birth, which indicates the ancestry, seem to
" exert a marked influence on the stature/' Tor instance, it is
established, " that residence in the Western States, during the
" years of growth, tends to produce increase of stature." On the
other hand, it is certain that with sailors, their life delays growth,
as shewn " by the great difference between the statures of soldiers
" and sailors at the ages of seventeen and eighteen years." Mr. B.
A. Gould endeavoured to ascertain the nature of the influences
which thus act on stature ; but he arrived only at negative results,
namely, that they did not relate to climate, the elevation of the )
land, soil, nor even " in any controlling degree " to the abundance I
or the need of the comforts of life. This latter conclusion is
directly opposed to that arrived at by Villerme, from the statistics
of the height of the conscripts in different parts of France. When
we compare the differences in stature between the Polynesian
chiefs and the lower orders within the same islands, or between
the inhabitants of the fertile volcanic and iow barren coral islands
of the same ocean, 18 or again between the Fuegians on the eastern
and western shores of their country, where the means of subsis-
tence are very different, it is scarcely possible to avoid the con-
clusion that better food and greater comfort do influence stature.
But the preceding statements shew how difficult it is to arrive
at any precise result. Dr. Beddoe has lately proved that, with
the inhabitants of Britain, residence in towns and certain occupa-
tions have a deteriorating influence on height ; and he infers that
the result is to a certain extent inherited, as is likewise the case
in the United States. Dr. Beddoe further believes that wherever
a " race attains its maximum of physical development, it rises
" highest in energy and moral vigour." 19
Whether external conditions produce any other direct effect t
on man is not known. It might have been expected that dif-
ferences of climate would have had a marked influence, in as much
as the lungs and kidneys are brought into activity under a low
17 ' Investigations in Military and 289. There is also a remarkable
Anthrop. Statistics,' &c. 1869, by difference in appearance between
B. A. Gould, p. 93, 107, 126, 131, the closely-allied Hindoos inhabiting
134. the Upper Ganges and Bengal; see
18 For the Polynesians, see Prich- Elphinstone's ' History of India/ vol.
ard's < Physical Hkt. of Mankind/ i. p. 324.
Tol. v. 1847, p. 145, 283. Also 19 'Memoir^ Anthropolog. Soc.
fjtodron, * Be l'Espfcce/ torn. ii. p. vol. iii. 1867-69, pp. 561, 565, 567,
32 The Descent of Man. Pabt 1
temperature, and the liver and skin under a high one. 20 It was
formerly thought that the colour of the skin and the character
of the hair were determined by light or heat ; and although it
can hardly be denied that some effect is thus produced, almost
all observers now agree that the effect has been very small, even
after exposure during many ages. But this subject will be more
properly discussed when we treat of the different races of man-
kind. With our domestic animals there are grounds for
believing that cold and damp directly affect the growth of the
hair ; but I have not met with any evidence on this head in the
case of man.
Effects of the increased Use and Disuse of Parts. — It is well
known that use strengthens the muscles in the individual, and
complete disuse, or the destruction of the proper nerve, weakens
them. When the eye is destroyed, the optic nerve often becomes
atrophied. When an artery is tied, the lateral channels increase
not only in diameter, but in the thickness and strength of their
coats. When one kidney ceases to act from disease, the other
increases in size, and does double work. Bones increase not
only in thickness, but in length, from carrying a greater weight. 21
Different occupations, habitually followed, lead to changed
proportions in various parts of the body. Thus it was ascertained
by the United States Commission M that the legs of the sailors
employed in the late war were longer by 0*217 of an inch, than
those of the soldiers, though the sailors were on an average
shorter men; whilst their arms were shorter by 1*09 of an inch,
and therefore, out of proportion, shorter in relation to their
lesser height. This shortness of the arms is apparently due to
their greater use, and is an unexpected result : but sailors
chiefly use their arms in pulling, and not in supporting weights.
With sailors, the girth of the neck and the depth of the instep
are greater, whilst the circumference of the chest, waist, and
hips is less, than in soldiers.
Whether the several foregoing modifications would become
hereditary, if the same habits of life were followed during many
generations, is not known, but it is probable. Bengger 123 attri-
butes the thin legs and thick arms of the Payaguas Indians to
20 Dr. Brakenridge, * Theory of Dr. Jaeger, "Ueber das L'angen-
Diathesis,' 'Medical Times/ June 19 wachsthum der Knochen," * Jena-
and July 17, 1869. ischen Zeitschrift/ B. v. Heft i.
21 I have given authorities for 22 ' Investigations/ &c. By B. A*
these several statements in my Gould, 1869, "p. 288.
* Variation of Animals Tinder Do- 2S 'S'augethiere von Paraguay
mestication/ vol. ii. pp. 297-300. 1830, s. 4.
Chap. II, Manner of Development 33
successive generations having passed nearly their whole lives in
canoes, with their lower extremities motionless. Other writers
have come to a similar conclusion in analogous cases. According
to Cranz, 124 who lived for a long time with the Esquimaux, " the
" natives believe that ingenuity and dexterity in seal-catching
" (their highest art and virtue) is hereditary ; there is really
" something in it, for the son of a celebrated seal-catcher will
•' distinguish himself, though he lost his father in childhood."
But in this case it is mental aptitude, quite as much as bodily
structure, which appears to be inherited. It is asserted that
the hands of English labourers are at birth larger than those of
the gentry. 26 From the correlation which exists, at least in
some cases, 26 between the development of the extremities and of
the jaws, it is possible that in those classes which do not labour
much with their hands and feet, the jaws would be reduced in
size from this cause. That they are generally smaller in refined
and civilised men than in hard-working men or savages, is certain.
But with savages, as Mr. Herbert Spencer ^ has remarked, the
greater use of the jaws in chewing coarse, uncooked food, would
act in a direct manner on the' masticatory muscles, and on the
bones to which they are attached. In infants, long before birth,
the skin on the soles of the feet is thicker than on any other part
of the body ; 28 and it can hardly be doubted that this is due
to the inherited effects of pressure during a long series of
generations.
It is familiar to every one that watchmakers and engravers
are liable to be short-sighted, whilst men living much out of
doors, and especially savages, are generally long-sighted. 29 Short-
sight and long-sight certainly tend to be inherited. 30 The
inferiority of Europeans, in comparison with savages, in eye-
sight and in the other senses, is no doubt the accumulated and
transmitted effect of lessened use during many generations ; for
Eengger 31 states that he has repeatedly observed Europeans,
24 * History of Greenland/ Eng. (' Sanitary Memoirs of the War of
translat. 1767, vol. i. p. 230. the Rebellion/ 1869, p. 530), has
25 * Intermarriage.' By Alex, proved this to be the case ; and he
Walker, 1838, p. 377. accounts for it by the ordinary
28 • The Variation of Animals range of vision in sailors being " re-
under Domestication, vol. i. p. 173. " stricted to the length of the vessel
27 * Principles of Biology/ vol. i. " and the height of the masts."
p. 455. 30 * The Variation of Animals
28 Paget, ' Lectures on Surgical under Domestication/ vol. i. p. 8.
Pathology/ vol. ii. 1853, p. 209. 31 * S'augethiere von Paraguay,'
28 It is a singular and unex- s. 8, 10. I have had good opportuni-
pected fact that sailors are inferior ties for observing the extraordinary
to landsmen in tjheir mean distanoe power of eyesight in the Fuegians.
of distinct vision. Dr. B. A. Gould See also Lawrence ('Lectures ou
»
34 The Descent of Alan. pji bt X
who had been brought up and spent their whole lives with the
wild Indians, who nevertheless did not equal them in the sharp-
ness of their senses. The same naturalist observes that the
cavities in the skull for the reception of the several sense-organs
are larger in the American aborigines than in Europeans ; and
this probably indicates a corresponding difference in the dimen-
sions of the organs themselves. Blumenbach has also remarked
on the large size of the nasal cavities in the skulls of the
American aborigines, and connects this fact with their remarkably
acute power of smell. The Mongolians of the plains of Northern
Asia, according to Pallas, have wonderfully perfect senses ; and
Prichard believes that the great breadth of their skulls across
the zygomas follows from their highly-developed sense-organs. 32
The Quechua Indians inhabit the lofty plateaux of Peru ; and
Alcide d'Orbigny states 83 that, from continually breathing a
highly rarefied atmosphere, they have acquired chests and lungs
of extraordinary dimensions. The cells, also, of the lungs are
larger and more numerous than in Europeans. These observa-
tions have been doubted ; but Mr. D. Forbes carefully measured
many Aymaras, an allied race, living at the height of between
10,000 and 15,000 feet; and he informs me 84 that they
differ conspicuously from the men of all other races seen by him
in the circumference and length of their bodies. In his table of
measurements, the stature of each man is taken at 1000, and the
other measurements are reduced to this standard. It is here
seen that the extended arms of the Aymaras are shorter than
those of Europeans, and much shorter than those of Negroes.
The legs are likewise shorter ; and they present this remarkable
peculiarity, that in every Aymara measured, the femur is actually
shorter than the tibia. On an average, the length of the femur
to that of the tibia is as 211 to 252 ; whilst in two Europeans,
measured at the same time, the femora to the tibiae were as 244
to 230 ; and in three Negroes as 258 to 241. The humerus is
likewise shorter relatively to the forearm. This shortening of
that part of the limb which is nearest to the body, appears to be,
as suggested to me by Mr. Forbes, a case of compensation in
Physiology/ &c, 1822, p. 404) on bach, vol. i. 1851, p. 311; for the
this same subject. M. Giraud-Teulon statement by Pallas, vol. iv. 1844,
has recently collected (* Revue des p. 407.
Cours Scientifiques,* 1870, p. 625) ™ Quoted by Prichard, * Re-
ft large and valuable body of evidence searches into the Phys. Hist, of Man-
proving that the cause of short- kind/ vol. v. p. 463.
Bight, " (Test le travail assidu, de 34 Mr. Forbes' valuable paper i*
prci." now published in the * Journal of
** Prichard, ' Phys. Hist, of Man- the Ethnological Sec. of London,
kind/ on the authority of Blumen- new series, vol. ii 1870, p. 103.
CaA*. II. , Manner of Development 33
relation with the greatly increased length of the trunk. The
Aymaras present some other singular points of structure, foi
instance, the very small projection of the heel.
These men are so thoroughly acclimatised to their cold and
lofty abode, that when formerly carried down by the Spaniards
to the low eastern plains, and when now tempted down by high
wages to the gold-washings, they suffer a frightful rate of mor-
tality. Nevertheless Mr. Forbes found a few pure families
which had survived during two generations : and he observed that
they still inherited their characteristic peculiarities. But it was
manifest, even without measurement, that these peculiarities
had all decreased ; and on measurement, their bodies were found
not to be so much elongated as those of the men on the high
plateau ; whilst their femora had become somewhat lengthened,
as had their tibiae, although in a less degree. The actual
measurements may be seen by consulting Mr. Forbes's memoir.
From these observations, there can, I think, be no doubt that
residence during many generations at a great elevation tends,
both directly and indirectly, to induce inherited modifications
in the proportions of the body. 35
Although man may not have been much modified during
the latter stages of his existence through the increased or de-
creased use of parts, the facts now given shew that his liability in
this respect has not been lost ; and we positively know that the
same law holds good with the lower animals. Consequently we •
may infer that when at a remote epoch the progenitors of man
were in a transitional state, and were changing from quadrupeds *
into bipeds, natural selection would probably have been greatly
aided by the inherited effects of the increased or diminished use
of the different parts of the body.
Arrests of Development. — There is a difference between arrested
development and arrested growth, for parts in the former state
continue to grow whilst still retaining their early condition.
Various monstrosities come under this head ; and some, as a
cleft-palate, are known to be occasionally inherited. It will
suffice for our purpose to refer to the arrested brain-development
of microcephalous idiots, as described in Vogt's memoir. 86
Their skulls are smaller, and the convolutions of the brain
are less complex than in normal men. The frontal sinus, or the
83 Dr. Wilckens (' Landwirth- regions, have their frames modified,
schaft. Wochenblatt,' No. 10, 1869) 3e 'Memoire sur les Microce-
has lately published an interesting phales,' 1867, pp. 50, 125, 169, 171,
Essay shewing how domestic ani 184-193.
mala, which live in mountainous
D 2
36 The Descent of Man, Past L
projection over the eye-brows, is largely developed, and the jaws
are prognathous to an " effrayant" degree ; so that these idiots
somewhat resemble the lower types of mankind. Their in-
telligence, and most of their mental faculties, are extremely
feeble. They cannot acquire the power of speech, and are
wholly incapable of prolonged attention, but are much given to
imitation. They are strong and remarkably active, continually
gamboling and jumping about, and making grimaces. They
often ascend stairs on all-fours; and are curiously fond of
climling up furniture or trees. "We are thus reminded of the
delight shewn by almost all boys in climbing trees; and this
again reminds us how lambs and kids, originally alpine animals,
delight to frisk on any hillock, however small. Idiots also
resemble the lower animals in some other respects; thus several
cases are recorded of their carefully smelling every mouthful of
food before eating it. One idiot is described as often using his
mouth in aid of his hands, whilst hunting for lice. They are
often filthy in their habits, and have no sense of decency ; and
several cases have been published of their bodies being re-
markably hairy. 37
Beversion. — Many of the cases to be here given, might have
been introduced under the last heading. When a structure
is arrested in its development, but still continues growing,
until it closely resembles a corresponding structure in some
lower and adult member of the same group, it may in one sense
be considered as a case of reversion. The lower members in a
group give us some idea how the common progenitor was
probably constructed ; and it is hardly credible that a complex
part, arrested at an early phase of embryonic development, should
go on growing so as ultimately to perform its proper function,
unless it had acquired such power during some earlier state of
existence, when the present exceptional or arrested structure
was normal. The simple brain of a microcephalous idiot, in as
far as it resembles that of an ape, may in this sense be said to
offer a case of reversion. 38 There are other cases which come
37 Prof. Laycock sums up the pp. 46-51. Pinel has also given a
character of brute-like idiots by striking case of hairiness in an
calling them theroid ; * Journal of idiot.
Mental Science,* July 1863. Dr. 38 In my * Variation of Animals
Scott (' The Deaf and Dumb/ 2nd under Domestication * (vol. ii. p. 57),
edit., 1870, p. 10) has often ob- I attributed the not very rare cases
served the imbecile smelling their of supernumerary mammae in women
food. See, on this same subject, to reversion. I was led to this as a
and on the hairiness of idiots, Dr. probable conclusion, by the additional
Mandsley, < Body and Mind,' 1870, mammae being generally plaosd
Chap. II.
Manner of Development
37
more strictly under our present head of reversion. Cortain
structures, regularly occurring in the lower members of the group
symmetrically on the breast; and
more especially from one case, in
which a single efficient mamma
occurred in the inguinal region of
a woman, the daughter of another
woman with supernumerary mam-
mae. But 1 now find (see, for in-
stance, Prof. Preyer, * Der Kanapf
um das Dasein,' 1869, s. 45) that
mammas erraticce occur in oUielt
situations, as -on the back, in the\
armpit, and on the thigh ; the
mammae in this latter instance
ha ring given so much milk that the
child was thus nourished. The pro-
bability that the additional mamma)
are due to reversion is i;hus much
weakened ; nevertheless, it still
seems to me probable, because two
pairs are often found symmetrically
on the breast ; and of this I myself
have received information in several
cases. It is well known that some
Lemurs normally have two pairs of
mammae on the breast. Five cases
have been recorded of the presence
of more than a pair of mammae (of
course rudimentary) in the male
sex of mankind ; see * Journal of
Anat. and Physiology,' 1872, p. 56,
for a case given by Dr. Handyside,
in which two brothers exhibited
this peculiarity ; see also a paper by
Dr. Barteis, in 'Reichert's and du
Bois Reymond's Archiv./ 1872, p.
304. In one of the cases alluded to
by Dr. Barteis, a man bore five
mammas, one being medial and
placed above the navel; Meckel
von Hemsbach thinks that this
latter case is illustrated by a
medial mamma occurring in certain
Cheiroptera. On the whole, we may
well doubt if additional mammae
would ever have been developed in
both sexes of mankind, had not his
early progenitors been provided with
more than a single pair.
In the above work (vol. ii. p. 12),
I also attributed, though with much
hesitation, the frequent cases of
polydactylism in men and various
animals to reversion. I was partly
led to this through Prof. Owen*s
statement, that some of the Ichthy-
opterygia possess more than five
digits, and therefore, as I supposed,
had retained a primordial condition ;
but Prof. Gegenbaur ('Jenaischen
Zeitschrift,' B. v. Heft 3, s. 341),
disputes Owen's conclusion. On the
other hand, according to the opinion
lately advanced by Dr. Giinther, on
the paddle of Ceratodus, which is
provided with articulated bony rays
on both sides of a central chain or
bones, there seems no great difficulty
in admitting that six or more digits
on one side, or on both sides, might
reappear through reversion. I am
informed by Dr. Zouteveen that
there is a case on record of a man
having twenty-four fingers and
twenty-four toes ! I was chiefly led
to the conclusion that the presence
of supernumerary digits might be due
to reversion from the fact that such
digits, not only are strongly in-
herited, but, as I then believed, had
the power of regrowth after ampu-
tation, like the normal digits of the
lower vertebrata. But I have ex-
plained in the Second Edition of my
Variation under Domestication why
I now place little reliance on the
recorded cases of such regrowth.
Nevertheless it deserves notice, in
as much as arrested development
and reversion are intimately related
processes ; that various structures
in an embryonic or arrested con-
dition, such as a cleft palate, bifid
uterus, &c, are frequently accom-
panied by polydactylism. This has
been strongly insisted on by Meckel
and Isidore Geoffroy St.-Hilaire. But
at present it is the safest course to
give up altogether the idea thnt
there is any relation between the
development of supernumerary di-
gits and reversion to some lowlf
crganised progenia of man.
$$ The Descent of Man. Part I,
to which man belongs, occasionally make their appearance in
him, though not found in the normal human embryo; or, it
normally present in the human embryo, they become abnormally
developed, although in a manner which is. normal in the lower
members of the group. These remarks will be rendered clearer
by the following illustrations.
In various mammals the uterus graduates from a double
organ with two distinct orifices and two passages, as in the
marsupials, into a single organ, which is in no way double
except from having a slight internal fold, as in the higher apes
and man. The rodents exhibit a perfect series of gradations
between these two extreme states. In all mammals the uterus
is developed from two simple primitive tubes, the inferior
portions of which form the cornua ; and it is in the words of
Dr. Farre, " by the coalescence of the two cornua at their lower
" extremities that the body of the uterus is formed in man ;
" while in those animals in which no middle portion or body
" exists, the cornua remain ununited. As the development of
" the uterus proceeds, the two cornua become gradually shorter,
" until at length they are lost, or, as it were, absorbed into the
" body of the uterus." The angles of the uterus are still
produced into cornua, even in animals as high up in the scale as
the lower apes and lemurs.
Now in women, anomalous cases are not very infrequent, in
which the mature uterus is furnished with cornua, or is partially
divided into two organs; and such cases, according to Owen,
repeat "the grade of concentrative development," attained by
certain rodents. Here perhaps we have an instance of a simple
arrest of embryonic development, with subsequent growth and
perfect functional development ; for either side of the partially
double uterus is capable of performing the proper office of
gestation. In other and rarer cases, two distinct uterine cavities
are formed, each having its proper orifice and passage. 39 No such
stage is passed through during the ordinary development of the
embryo ; and it is difficult to believe, though perhaps not im-
possible, that the two simple, minute, primitive tubes should
know how (if such an expression may be used) to grow into two
39 See Dr. A. Farre's well-known brates/ vol. iii., 1868, p. 687. Pro-
article in the * Cyclopaedia of Ana- fessor Turner in 'Edinburgh Meli-
tomy and Fhysioiogy,' vol. v. 1859, c«1 Journal/ February 1865.
, 642, Owen, ' Anatomy of Verle-
Chap. II. Manner of Development. 39
distinct uteri, each with a well-constructed orifice and passage,
and each furnished with numerous muscles, nerves, glands and
vessels, if they had not formerly passed through a similar course
of development, as in the case of existing marsupials. No ono
will pretend that so perfect a structure as the abnormal double
uterus in woman could be the result of mere chance. But the
principle of reversion, by which a long-lost structure is called
back into existence, might serve as the guide for its full develop-
ment, even after the lapse of an enormous interval of time.
Professor Canestrini, after discussing the foregoing and various
analogous cases, arrives at the same conclusion as that just
given. He adduces another instance, in the case of the malar
bone, 40 which, in some of the Quadrumana and other mammals,
normally consists of two portions. This is its condition in the
human foetus when two months old ; and through arrested develop-
ment, it sometimes remains thus in man when adult, more
especially in the lower prognathous races. Hence Canestrini
concludes that some ancient progenitor of man must have had
this bone normally divided into two portions, which afterwards
became fused together. In man the frontal bone consists of a
single piece, but in the embryo, and in children, and in almost
all the lower mammals, it consists of two pieces separated by a
distinct suture. This suture occasionally persists more or less
distinctly in man after maturity ; and more frequently in ancient
than in recent crania, especially, as Canestrini has observed, in
those exhumed from the Drift, and belonging to the brachyce-
phalic typo. Here again he comes to the same conclusion as in
the analogous case of the malar bones. In this, and other instances
presently to be given, the cause of ancient races approaching the
lower animals in certain characters more frequently than do the
modern races, appears to be, that the latter stand at a somewhat
i0 < Annuario della Soc. dei Natu- tected in about two per cent, of
ralisti in Modena/ 1867, p. 83. adult skulls; he also remarks that
Prof. Canestrini gives extracts on it more frequently occurs in pro-
tnis subject from various authorities, gnathous skulls, not of the Aryan
Laurillard remarks, that as he has race, than in others. See also G.
found a complete similarity in the Delorenzi on the same subject ; * Tre
form, proportions, and connection of nuovi casi d' an om alia dell'osso,
the two malar bones in several malare/ Torino, 1872. Also, E.
human subjects and in certain apes, Morselli, * Sopra una rara anomalia
he cannot consider this disposition dell* osso malare/ Modena, 1872.
©f the parts as simply accidental. Still more recently Gruber has
Another paper on this same anomaly written a pamphlet on the division
has been published by Dr. Saviotti of this bone. 1 give these leferencea
in the ' Gazzetta delle Cliniche/ because a reviewer, without any
Turin, 1871, where he says that grounds or scruples, has thrown
traces ef the division may be de- doubts or. my statements.
40 The Descent of Man. P^kf I,
greater distance in the long line of descent from their early semi-
fmman progenitors.
Various other anomalies in man, more or less analogous to the
foregoing, have been advanced by different authors, as cases of
reversion ; but these seem not a little doubtful, for we have to
descend extremely low in the mammalian series, before we find
such structures normally present. 41
In man, the canine teeth are perfectly efficient instruments for
mastication. But their true canine character, as Owen 42 re-
marks, " is indicated by the conical form of the crown, which
" terminates in an obtuse point, is convex outward and flat or
" sub-concave within, at the base of which surface there is a
" feeble prominence. The conical form is best expressed in the
" Melanian races, especially the Australian. The canine is more
" deeply implanted, and by a stronger fang than the incisors.'*
Nevertheless, this tooth no longer serves man as a special weapon
for tearing his enemies or prey ; it may, therefore, as far as its
proper function is concerned, be considered as rudimentary. In
every large collection of human skulls some may be found, as
Hackel 43 observes, with the canine teeth projecting considerably
beyond the others in the same manner as in the anthropomorphous
apes, but in a less degree. In these cases, open spaces between
the teeth in the one jaw are left for the reception of the canines
of the opposite jaw. An interspace of this kind in a Kaffir
skull, figured by Wagner, is surprisingly wide. 44 Considering
how few are the ancient skulls which have been examined,
compared to recent skulls, it is an interesting fact that in at
least three cases the canines project largely; and in the Nauletto
jaw they are spoken of as enormous. 45
41 A whole series of cases is given if in any way serviceable, for in-
by Isid. Gebffroy St.-Hilaire, * Hist, stance, in shortening and simplifying
des Anomalies/ torn. iii. p. 437. the course of development ? Ard
A reviewer (' Journal of Anat. and again, why should not injurious ab-
Physiology/ 1871, p. 366) blames normalities, such as atrophied or hy-
me much for not having discussed pertrophied parts, which have no
the numerous cases, which have relation to a former state of exist-
been recorded, of various parts ar- ence, occur at an early period, as
rested in their development. He well as during maturity ?
says that, according to my theory, ** * Anatomy of Vertebrates,* vol.
" every transient condition of an iii. 1868, p. 323.
" organ, during its development, is 43 *Generelle Morphologic/ 1866,
** not only a means to an end, but B. ii. s. civ.
" once was an end in itself." This * 4 Carl Vogt's * Lectures on Man,*
does not seem to me necessarily to Eng. translat. 1864, p. 151.
hold good. Why should not varia- 45 C. Carter Blake, on a jaw
tions occur during an early period from La Naulette, i Anthropolog.
of development, having no relation Review/ 1867, p. 295. Schaaff-
1,0 reversion; yet such variations hausen, ibid- 1868, p. 426.
might be preserved and accumulated,
Chap. II. Maimer of Development. 41
Of the anthropomorphous apes the males alone have their
canines fully developed ; but in the female gorilla, and in a less
degree in the female orang, these teeth project considerably
beyond the others; therefore the fact, of which I have been
assured, that women sometimes have considerably projecting
canines, is no serious objection to the belief that their occasional
great development in man is a case of reversion to an ape-like
progenitor. He who rejects with scorn the belief that the shape
of his own canines, and their occasional great development in
other men, are due to our early forefathers haviDg been pro-
vided with these formidable weapons, will probably reveal, by
sneering, the line of his descent. For though he no longer
intends, nor has the power, to use these teeth as weapons, he will
unconsciously retract his " snarling muscles" (thus named by
Sir C. Bell), 46 so as to expose them ready for action, like a dog
prepared to fight.
Many muscles are occasionally developed in man, which are
proper to the Quadrumana or other mammals. Professor
Vlacovich 47 examined forty male subjects, and found a muscle,
called by him the ischio-pubic, in nineteen of them ; in three
others there was a ligament which represented this muscle; and
in the remaining eighteen no trace of it. In only two out of
thirty female subjects was this muscle developed on both sides,
but in three others the rudimentary ligament was present. This
muscle, therefore, appears to be much more common in the
male than in the female sex ; and on the belief in the descent
of man from some lower form, the fact is intelligible ; for it
has been detected in several of the lower animals, and in all
of these it serves exclusively to aid the male in the act of
reproduction.
Mr. J. Wood, in his valuable series of papers, 48 has minutely
described a vast number of muscular variations in man, which
resemble normal structures in the lower animals. The muscles
« « The Anatomy of Expression/ pp. 241, 242 ; vol. xv. 1867, p. 544 ;
1844, pp. 110, 131. t vol. xvi. 1868, p. 524. I may here
47 Quoted by Prof. Canestrini in add that Dr. Murie and Mr. St.
the 'Annuario/ &c, 1867, p. 90. George Mivart have shewn in their
48 These papers deserve careful Memoir on the Lemuroidea (' Tran-
study by any one who desires to sact. Zoolog. Soc* vol. vii. 1869,
learn how frequently our muscles p. 96), how extraordinarily variable
rary, and in varying come to re- some of the muscles are in these
semble those of the Quadrumana. animals, the lowest members of the
The following references relate to Primates. Gradations, also, in the
the few points touched on in my muscles leading to structures found
text : * Proc. Royal Soc. vol. xiv. in animals still lower in the scale,
1865, pp. 379-384; vol. xv. 1866, ve numerous in the Lemuroidea,
42 TJie Descent of Man. Faet I,
which closely resemble those regularly present in our nearest
allies, the Quadrumana, are too numerous to be here even
specified. In a single male subject, having a strong bodily
frame, and well-formed skull, no less than seven muscular varia-
tions were observed, all of which plainly represented muscles
proper to various kinds of apes. This man, for instance, had on
both sides of his neck a true and powerful " levator claviculce"
such as is found in all kinds of apes, and which is said to occur
in about one out of sixty human subjects. 49 Again, this man
had " a special abductor of the metatarsal bone of the fifth
" digit, such as Professor Huxley and Mr. Flower have shewn
" to exist uniformly in the higher and lower apes." I will give
only two additional cases; the acromio-basilar muscle is found
m all mammals below man, and seems to be correlated with a
quadrupedal gait, 60 and it occurs in about one out of sixty
human subjects. In the lower extremities Mr. Bradley 51 found
an abductor ossis metatarsi quinti in both feet of man ; this muscle
had not up to that time been recorded in mankind, but is
always present in the anthropomorphous apes. The muscles of
the hands and arms — parts which are so eminently characteristic
of man— are extremely liable to vary, so as to resemble the
corresponding muscles in the lower animals. 62 Such resem-
blances are either perfect or imperfect; yet in the latter case
they are manifestly of a transitional nature. Certain variations
are more common in man, and others In woman, without our
being able to assign any reason. Mr. Wood, after describing
numerous variations, makes the following pregnant remark.
" Notable departures from the ordinary type of the muscular
" structures run in grooves or directions, which must be taken
" to indicate some unknown factor, of much importance to a
" comprehensive knowledge of general and scientific anatomy . ,,6S
49 See also Prof. Macalister in able case of variation in the human
' Proc. R. Irish Academy,* vol. x. fiexor pollicis longus, adds, *< This.
1868, p. 124. " remarkable example shews that
50 Mr. Champneys in ' Journal of " man may sometimes possess the
Anat. and Phys/ Nov., 1871, p. 178. " arrangement of tendons of thumb
51 ' Journal of Anat. and Phys.' " and fingers characteristic of the
May, 1872, p. 421. "macaque; but whether such a
53 Prof. Macalister (ibid. p. 121) " case should be regarded as a
has tabulated his observations, and " macaque passing upwards into a
finds that muscular abnormalities " man, or a man passing downwards
are most frequent in the fore-arms, " into a macaque, or as a congenita]
cecondly, in the face, thirdly, in the " freak of nature, I cannot under-
foot, &c. " take to say." It is satisfactory
a * The Rev. Dr. Haughton, after to hear so capable an anatomist,
giving ('Proc. R. Irish Academy,' and so embittered an opponent of
June 27, 1864, p. 715) a remark- evolutionism, admitting even the
Chap. II. Manner of Development. 43.
That this unknown factor is reversion to a former state of
existence may be admitted as in the highest degree probable M
It is quite incredible that a man should through mere accident
abnormally resemble certain apes in no less than seven of his
muscles, if there had been no genetic connection between them.
On the other hand, if man is descended from some ape-like
creature, no valid reason can be assigned why certain muscles
should not suddenly reappear after an interval of many thou-
sand generations, in the same manner as with horses, asses, and
mules, dark-coloured stripes suddenly reappear on the legs,
and shoulders, after an interval of hundreds, or more probably
of thousands of generations.
These various cases of reversion are so closely related to those
of rudimentary Organs given in the first chapter, that many of
them might have been indifferently introduced either there or
here. Thus a human uterus furnished with cornua may be said
to represent, in a rudimentary condition, the same organ in its
normal state in certain mammals. Some parts which are rudi-
mentary in man, as the os coccyx in both sexes, and the mammas
in the male sex, are always present; whilst others, such as the
supracondyloid foramen, only occasionally appear, and therefore
might have been introduced under the head of reversion. These
several reversionary structures, as well as the strictly rudi-
mentary ones, reveal the descent of man from some lower form
in an unmistakable manner.
Correlated Variation, A-In man, as in the lower animals, many
structures are so intimately related, that when one part varies
so does another, without our being able, in most cases, to assign
any reason. We cannot ¥ say whether the one part governs the
other, or whether both are governed by some earlier developed
possibility of either of his first pro- closely the variations resemble the
positions. Prof. Macalister has also normal muscles of the lower ani-
described (* Proc. R. Irish Acad.* mals. He sums up by remarking,
vol. x. 1864, p. 138) variations in " It will be enough for my purpose
the flexor pollicis longus, remarkable " if I have succeeded in shewing
from their relations to the same " the more important forms which,
muscle in the Quadrumana. " when occurring as varieties in the
54 Since the first edition of this " human subject, tend to, exhibit in
book appeared, Mr. Wood has pub- " a sufficiently marked manner what
Ushed another memoir in the 4 Phil. " may be considered as proofs and
Transactions,* 1870, p. 83, on the " examples of the Darwinian prin-
varieties of the muscles of the human " ciple of reversion, or law of in-
neck, shoulder, and chest. He here " heritance, in this department of
shews how extremely variable these " anatomical science."
muscles are. ind how often and how
44 The Descent of Man. Part I
part Various monstrosities, as I. Geoffroy repeatedly insists, arc
thus intimately connected. Homologous structures are par-
ticularly liable to change together, as we see on the opposite
sides of the body, and in the upper and lower extremities.
Meckel long ago remarked, that when the muscles of the arm
depart from their proper type, they almost always imitate those
of the leg ; and so, conversely, with the muscles of the legs. The
organs of sight and hearing, the teeth and hair, the colour of the
ckin and of the hair, colour and constitution, are more or less cor-
related. 55 Professor Schaaffhausen first drew attention to the
relation apparently existing between a muscular frame and
the strongly-pronounced supra-orbital ridges, which are so
characteristic of the lower races of man.
Besides the variations which can be grouped with more or
less probability under the foregoing heads, there is a large class
of variations which may be provisionally called spontaneous, for
to our ignorance they appear to arise without any exciting
cause. It can, however, be shewn that such variations, whether
consisting of slight individual differences, or of strongly-marked
and abrupt deviations of structure, depend much more on the
constitution of the organism than on the nature of the condi-
tions to which it has been subjected. 56
Bate of Increase, — Civilised populations have been known
under favourable conditions, as in the United States, to double
their numbers in twenty-five years ; and, according to a calcula-
tion by Euler, this might occur in a little over twelve years.* 7 At
the former rate, the present population of the United States
(thirty millions), would in 657 years cover the whole terraqueous
globe so thickly, that four men would have to stand on each
square yard of surface. The primary or fundamental check to
the continued increase of man is the difficulty of gaining
subsistence, and of living in comfort. We may infer that this is
the case from what we see, for instance, in the United States,
where subsistence is easy, and there is plenty of room. If such
means were suddenly doubled in Great Britain, our number would
be quickly doubled. With civilised nations this primary check
acts chiefly by restraining marriages. The greater death-rate of
infants in the poorest classes is also very important; as well as
15 The authorities for these seve- my 'Variation of Animals and Plants
ra) statements are given in my under Domestication.*
* Variation of Animals under Do- 57 See the ever memorable ' Essay
mesticaticn,' vol. ii. pp. 320-335. on the Principle of Population/ by
*■ This whole subject has been the R«v. T. Malthus, vol. i. 1826 jk
discussed in chap. siijL roj. ij. of 6, 517.
CiiAi\ II. Manner of Development. 45
the greater mortality, from various diseases, of "the inhabitants of
crowded and miserable houses, at all ages. The effects of severe
epidemics and wars are soon counterbalanced, and more than
counterbalanced, in nations placed under favourable conditions.
Emigration also comes in aid as a temporary check, but, with
the extremely poor classes, not to any great extent.
There is reason to suspect, as Malthus has remarked, that the
reproductive power is actually less in barbarous, than in civilised
races. We know nothing positively on this head, for with
savages no census has been taken; but from the concurrent
testimony of missionaries, and of others who have long resided
with such people, it appears that their families are usually small,
and large ones rare. This may be partly accounted for, as it is
believed, by the women suckling their infants during a long
time ; but it is highly probable that savages, who often suffer
much hardship, and who do not obtain so much nutritious food
as civilised men, would be actually less prolific. I have shewn
in a former work, 58 that all our domesticated quadrupeds and
birds, and all our cultivated plants, are more fertile than the
corresponding species in a state of nature. It is no valid
objection to this conclusion that animals suddenly supplied with
an excess of food, or when grown very fat ; and that most plants
on sudden removal from very poor to very rich soil, are
rendered more or less sterile. We might, therefore, expect that
civilised men, who in one sense are highly domesticated, would
be more prolific than wild men. It is also probable that the
increased fertility of civilised nations would become, as with our
domestic animals, an inherited character : it is at least known
that with mankind a tendency to produce twins runs in
families. 69
Notwithstanding that savages appear to be less prolific than
civilised people, they would no doubt rapidly increase if their
numbers were not by some means rigidly kept down. The San-
tali, or hill-tribes of India, have recently afforded a good illustra-
tion of this fact ; for, as shewn by Mr. Hunter, 60 they have
increased at an extraordinary rate since vaccination has been
introduced, other pestilences mitigated, and war sternly repressed.
This increase, however, would not have been possible had not
these rude people spread into the adjoining districts, and worked
for hire. Savages almost always marry ; yet there is some
prudential restraint, for they do not commonly marry at the
58 'Variation of Animals and Foreign Medico-Chirurg. Review,'
Plants under Domestication/ vol. ii. July, 1863, p. 170.
pp. 111-113, 163. 6 ° 'The Annals of Rural Bengal,
* Mr. Sedgwick, 'British and by W. W. Hunter, 186 H p. 259.
46 The Descent of Man. Pah? L
earliest possible age. The young men are often required to shew
that they can support a wife ; and they generally have first to
earn the price with which to purchase her from her parents.
With savages the difficulty of obtaining subsistence occasionally
limits their number in a much more direct manner than with
civilised people, for all tribes periodically suffer from severe
famines. At such times savages are forced to devour much bad
food, and their health can hardly fail to be injured. Many
accounts have been published of their protruding stomachs and
emaciated limbs after and during famines. They are then, also,
compelled to wander much, and, as I was assured in Australia,
their infants perish in large numbers. As famines are period-
ical, depending chiefly on extreme seasons, all tribes must
fluctuate in number. They cannot steadily and regularly
increase, as there is no artificial increase in the supply of food.
Savages, when hard pressed, encroach on each other's territories,
and war is the result ; but they are indeed almost always at war
with their neighbours. They are liable to' many accidents on
land and water in their search for food ; and in some countries
they suffer much from the larger beasts of prey. Even in
India, districts have been depopulated by the ravages o:
tigers.
Malthus has discussed these several checks, but he does not
lay stress enough on what is probably the most important of all,
namely infanticide, especially of female infants, and the habit of
procuring abortion. These practices now prevail in many
quarters of the world ; and infanticide seems formerly to have
prevailed, as Mr. M'Lennan 61 has shewn, on a still more extensive
scale. These practices appear to have originated in savages re-
cognising the difficulty, or rather the impossibility of supporting
all the infants that are born. Licentiousness may also be added
to the foregoing checks; but this does not follow from failing
means of subsistence; though there is reason to believe that in
some cases (as in Japan) it has been intentionally encouraged
as a means of keeping down the population.
If we look back to an extremely remote epoch, before man had
arrived at the dignity of manhood, he would have been guided
more by instinct and less by reason than are the lowest savages
at the present time. Our early semi-human progenitors would
not have practised infanticide or polyandry; for the instincts of
the lower animals are never so perverted ffl as to lead them re-
CJ * Primitive Marriage,' 1865. ments as follows on this passage :—
"A writer in the 'Spectator' "Mr. Darwin finds himself compelled
(Jlarcn liitn, 1871, p. 320) com- " to reintroduce a new doctrine of the
Cbap. ii. .Marnier of Development 47
gularly to destroy their own offspring, or to be quite devoid of
jealousy. There would have been no prudential restraint from
marriage, and the sexes would have freely united at an early age.
Hence the progenitors of man would have tended to increase
rapidly ; but checks of some kind, either periodical or constant,
must have kept down their numbers, even more severely than
with existing savages. What the precise nature of these, checks
were, we cannot say, any more than with most other animals.
We know that horses and cattle, which are not extremely prolific
animals, when first turned loose in South America, increased at
an enormous rate. The elephant, the slowest breeder of all
known animals, would in a few thousand years stock the whole
world. The increase of every species of monkey must be
checked by some means; but not, as Brehm remarks, by the
attacks of beasts of prey. No one will assume that the actual
power of reproduction in the wild horses and cattle of Americaj
was at first in any sensible degree increased ; or that, as each
district became fully stocked, this same power was diminished.
No doubt in this case, and in all others, many checks concur,
and different checks under different circumstances ; periodical
dearths, depending on unfavourable seasons, being probably the
most important of all. So it will have been with the early pro-
genitors of man.
Natural Selection, — We have now seen that man is variable in
body and mind ; and that the variations are induced, either
directly or indirectly, by the same general causes, and obe$ the
same general laws, as with the lower animals. Man has spread
widely over the face of the earth, and must have been exposed,
during his incessant migrations, 63 to the most diversified con-
ditions. The inhabitants of Tierra del Fuego, the Cape of Good
Hope, and Tasmania in the one hemisphere, and of the Arctic
regions in the other, must have passed through many climates,
" fall of man. He shews that the '* by the many foui customs, es-
" instincts of the higher animals " pecially as to marriage, of savage
" are far nobler than the habits of " tribes. What does the Jewish
•*• savage races of men, and he finds • " tradition of the moral degeuera-
" himself, therefore, compelled to " tion of man through his snatching
" re-introduce, — in a form of the " at a knowledge forbidden him
" substantial orthodoxy of which he " by his highest instinct assert
" appears to be quite unconscious, — " beyond this?"
** and to introduce as a scientific 6S See some good remarks to this
" hypothesis the doctrine that man's effect by W. Stanley Jevons, "A
" gain of knowledge was the cause of " Deduction from Darwin's Theory/
** a temporary but long-enduring * Nature,* 1869, p. 231.
"• racial deterioration, n& indicated
4§ The Descent of Man. Pas? L
and changed their habits many times, before they reached their
present homes. 64 The early progenitors of man must also havo
tended, like all other animals, to have increased beyond their
means of subsistence ; they must, therefore, occasionally have
been exposed to a struggle for existence, and consequently to the
rigid law of natural selection. Beneficial variations of all kinds
. will thus, either occasionally or habitually, have been preserved
I and injurious ones eliminated. I do not refer to strongly-marked
deviations of structure, which occur only at long intervals of
time, but to mere individual differences. We know, for instance,
that the muscles of our hands and feet, which determine our
powers of movement, are liable, like those of the lower animals, 65
to incessant variability. If then the progenitors of man inhabit-
ing any district, especially one undergoing some change in its
conditions, were divided into two equal bodies, the one half
which included all the individuals best adapted by their powers
of movement for gaining subsistence, or for defending themselves,
I would on an average survive in greater numbers, and procreate
1 more offspring than the other and less well endowed half.
Man in the rudest state in which he now exists is the most
dominant animal that has ever appeared on this earth. He has
spread more widely that any other highly organised form : and
all others have yielded before him. He manifestly owes this
immense superiority to his intellectual faculties, to his social
habits, which lead him to aid and defend his fellows, and to his
corporeal structure. * The supreme importance of these characters
has been proved by the final arbitrament of the battle for life.
Through his powers of intellect, articulate language has been
evolved; and on this his wonderful advancement has mainly
depended. As Mr. Chauncey Wright remarks : 66 " a psychological
" analysis of the faculty of language shews, that even the smallest
*' proficiency in it might require more brain power than the
" greatest proficiency in any other direction." He has invented
and is able to use various weapons, tools, traps, &c, with which
he defends himself, kills or catches prey, and otherwise obtains
food. He has made rafts or canoes for fishing or crossing over
to neighbouring fertile islands. He has discovered the art of
64 Latham, * Man and his Migra- " classed in any of the above
tions,' 1851, p. 135. " groups." These muscles differ
65 Messrs. Murie and Mivart in even on the opposite sides of the
their 'Anatomy of the Lemuroidea' same individual.
('Transact. Zoolog. Soc* vol. vii. 66 Limits of Natural Selection,
1869, pp. 96-98) s&y, "some muscles * North American Be new/ Oct.
** are so irregular in their distriba- 1870, p. 295.
** tics that the-"- cannot be weH
Chap. IT. Manner of Development 49
making fire, by which hard and stringy roots can bo rendered
digestible, and poisonous roots or herbs innocuous. This dis-
covery of fire, probably the greatest ever made by man, excepting
language, dates from before the dawn of, history. These several
inventions, by which man in the rudest state has become so pre-
eminent, are the direct results of the development of his powers
of observation, memory, curiosity, imagination, and reason. I
cannot, therefore, understand how it is that Mr. Wallace 67 main-
tains, that "natural selection could only have endowed the
" savage with a brain a little superior to that of an ape."
Although the intellectual powers and social habits of man are
of paramount importance to him, we must not underrate the
importanae of his bodily structure, to which subject the remain-
der of this chapter will be devoted ; the development of the in-
tellectual and social or moral faculties being discussed in a later
chapter.
Even to hammer with precision is no easy matter, as every
one who has tried to learn carpentry will admit. To throw a
stone with as true an aim as a Fuegian in defending himself, or
in killing birds, requires the most consummate perfection in the
correlated action of the muscles of the hand, arm, and shoulder,
and, further, a fine sense of touch. In throwing a stone or spear,
and in many other actions, a man mast stand firmly on his feet ;
and this again demands the perfect co-adaptation of numerous
muscles. To chip a flint into the rudest tool, or to form a
oarbed spear or hook from a bone, demands the use of a perfect
hand; for, as a most capable judge, Mr. Schoolcraft, 68 remarks,
the shaping fragments of stone into knives, lances, or arrow-heads,
67 'Quarterly Review/ April here resist quoting a most just
1869, p. 392. This subject is more remark by Sir J, Lubbock ( 4 Pre-
fuliy discussed in Mr. Wallace's historic Times,' 1865, p. 479) in
' Contributions to the Theory of reference to this paper, namely, that
Natural Selection/ 1870, in which Mi. Wallace, "with characteristic
all the essays referred to in this " unselfishness, ascribes it (i. e. the
work are republished. The ' Essay " idea of natural selection) unre-
on Man ' has been ably criticised by " servedly to Mr. Darwin, altnongh,
Prof. Claparede, one of the most «* as is well known, he struck out
distinguished zoologists in Europe, *' the idea independently, and pub-
in an article published in the " lished it, though not with the
' Bibliotheque Universelle/ June " same elaboration, at the same
1870. The remark quoted in my "time."
text will surprise every one who 8t Quoted by Mr. Lawson Tait in
has read Mr. Wallace's celebrated his * Law of Natural Selection/ —
paper on ' The Origin of Human 4 Dublin Quarterly Journal of Medi-
Races deduced from the Theory of cal Science/ Feb. 1869. Dr. Keller
Natural Selection/ originally pub- is likewise quoted to the same
hshed in the * Anthropological Re- effect,
view/ May 1864, p. clviii. I cannot
|o Vke Descent of Man. Pabt I
shews " extraordinary ability and long practice/' This is to a
great extent proved by the fact that primeval men practised a
division of labour; each man did not manufacture his own flint
tools or rude pottery, but certain individuals appear to have
devoted themselves to such work, no doubt receiving in exchange
the produce of the chase. Archaeologists are convinced that an
enormous interval of time elapsed before our ancestors thought
of grinding chipped flints into smooth tools. One can hardly
doubt, that a man-like animal who possessed a hand and arm
sufficiently perfect to throw a stone with precision, or to form a
flint into a rude tool, could, with sufficient practice, as far as
mechanical skill alone is concerned, make almost anything
which a civilised man can make. The structure of the hand in
this respect may be compared with that of the vocal organs,
which in the apes are used for uttering various signal-cries, or,
as in one genus, musical cadences; but in man the closely
similar vocal organs have become adapted through the inherited
effects of use for the utterance of articulate language.
/ Turning now to the nearest allies of men, and therefore to its
best representatives of our early progenitors, we find that the
hands of the Quadrumana are constructed on the same general
pattern as our own, but are far less perfectly adapted for diver-
; sified uses. Their hands do not serve for locomotion so well
as the feet of a dog ; as may be seen in such monkeys as the
chimpanzee and orang, which walk on the outer margins of
the palms, or on the knuckles. 69 Their hands, however, are
admirably adapted for climbing trees. Monkeys seize thin
branches or ropes, with the thumb on one side and the fingers
and palm on the other, in the same manner as we do. They can
thus also lift rather large objects, such as the neck of a bottle, to
their mouths. Baboons turn over stones, and scratch up roots
with their hands. They seize nuts, insects, or other small
objects with the thumb in opposition to the fingers, and no
doubt they thus extract eggs and the young from the nests of
birds. American monkeys beat the wild oranges on the branches
until the rind is cracked, and then tear it off with the fingers of
the two hands. In a wild state they break open hard fruits
with stones. Other monkeys open mussel-shells with the two
thumbs. With their fingers they pull out thorns and burs, and
hunt for each other's parasites. They roll down stones, or throw
them at their enemies : nevertheless, they are clumsy in these
various actions, and, as I have myself seen, are quite unable to
throw a stone with precision.
69 Ov, en, < Anatomy of Vertebrates/ vol. iii. p. 71,
Chap. II. Manner of Development. 51
It seems to me far from true that because " objects are grasped
" clumsily " by monkeys, " a much less specialised organ of
" prehension " would have served them 7P equally well with
their present hands. On the contrary, I see no reason to doubt
that more perfectly constructed hands would have been an
advantage to them, provided that they were not thus rendered
less fitted for climbing trees. We may suspect that a hand as
perfect as that of man would have been disadvantageous for
climbing ; for the most arboreal monkeys in the world, namely,
Ateles in America, Colobus in Africa, and Hylobates in Asia,
are either thumbless, or their toes partially cohere, so that their
limbs are converted into mere grasping hooks. 71
As soon as some ancient member in the great series of the
Primates came to be less arboreal, owing to a change in its
manner of procuring subsistence, or to some change in the
surrounding conditions, its habitual manner of progression would
have been modified : and thus it would have been rendered more
strictly quadrupedal or bipedal. Baboons frequent hilly and
rocky districts, and only from necessity climb high trees ; 7a and
they have acquired almost the gait of a dog. Man alone has
become a biped ; and we can, I think, partly see how he has
come to assume his erect attitude, which forms one of his most
conspicuous characters. Man could not have attained his present
dominant position in the world without the use of his hands,
which are so admirably adapted to act in obedience to his will.
Sir C. Bell 73 insists that " the hand supplies all instruments,
•' and by its correspondence with the intellect gives him univer-
" sal dominion." But the hands and arms could hardly have
become perfect enough to have manufactured weapons, or to
have hurled stones and spears with a true aim, as long as they
were habitually used for locomotion and for supporting the
whole weight of the body, or, as before remarked, so long as they
were especially fitted for climbing trees. Such rough treatment
would also have blunted the sense of touch, on which their
delicate use largely depends. From these causes alone it would
have been an advantage to man to become a biped; but for
i0 * Quarterly Review/ April but whethei a better climber than
1869, p. 392. the species of the allied genera, I do
71 In Hylobates syndactylus, as not know. It deserves notice that
*he name expresses, two of the toes the feet of the sloths, the most
regularly cohere ; and this, as Mr. arboreal animals in the world, are
Blyth informs me, is occasionally wonderfully hook-like,
the case with the toes of H. agilis, n Brehm, ' Thierleben/ B. i. s.
lar, and leuciscus. Colobus is strictly 80.
arboreal and extraordinarily active n "The Hand," &c. *Bridge-
(Brehm, « Thierleben,' B. i. s. 50), water Treatise/ 1833, p. 38.
E 2
52 The Descent of Man. Paet l
many actions it is indispensable that the arms and whole upper
part of the body should be free ; and he must for this end stand
firmly on his feet. To gain this great advantage, the feet have
been rendered flat ; and the great toe has been peculiarly modi-
fied, though this has entailed the almost complete loss of its
power of prehension. It accords with the principle of the
division of physiological labour, prevailing throughout the
animal kingdom, that as the hands became perfected for pre-
hension, the feet should have become perfected for support and
locomotion. With some savages, however, the foot has not
altogether lost its prehensile power, as shewn by their manner
of climbing trees, and of using them in other ways. 74
If it be an advantage to man to stand firmly on his feet and to
have his hands and arms free, of which, from his pre-eminent
success in the battle of life, there can be no doubt, then I can see
no reason why it should not have been advantageous to the
progenitors of man to have become more and more erect or
bipedal. They would thus have been better able to defend
themselves with stones or clubs, to attack their prey, or other-
wise to obtain food. The best built individuals would in the
long run have succeeded best, and have survived in larger
numbers. If the gorilla and a few allied forms had become
extinct, it might have been argued, with great force and apparent
truth, that an animal could not have been gradually converted
from a quadruped into a biped, as all the individuals in an
intermediate condition would have been miserably ill-fitted
for progression. But we know (and this is well worthy of
reflection) that the anthropomorphous apes are now actually in
an intermediate condition ; and no one doubts that they are o
the whole well adapted for their conditions of life. Thus the
gorilla runs with a sidelong shambling gait, but more commonly
progresses by resting on its bent hands. The long-armed apes
occasionally use their arms like crutches, swinging their bodies
forward between them, and some kinds of Hylobates, without
having been taught, can walk or run upright with tolerable
quickness ; yet they move awkwardly, and much less securely
than man. We see, in short, in existing monkeys a manner of
progression intermediate between that of a quadruped and a
u Hackel lias an excellent dis- foot as a prehensile organ by man ;
cussion on the steps by which man and has also written on the mannei
became a biped : * Natiirliche Schbp- of progression of the higher apes, to
fungsgeschichte/ 1868, s. 507. Dr. which I allude in the following
Biichner (* Conferences sur la Theorie paragraph : see also Owen (' Anatomy
Darwinienne,' 1869, p. 135) has of Vertebrates/ vol. iii, p. 71) ou
given good cases of the use of the this latter subject.
Chap. II. Manner of Development 53
biped ; but, as an unprejudiced judge 75 insists, the anthropomor-
phous apes approach in structure more nearly to the bipedal
than to the quadrupedal type.
As the progenitors of man became more and more erect, with
their hands and arms more and more modified for prehension
and other purposes, with their feet and legs at the same time
transformed for firm support and progression, endless other
changes of structure would have become necessary. The pelvis
would have to be broadened, the spine peculiarly curved, and the
head fixed in an altered position, all which changes have been
attained by man. Prof. Schaaff hausen 76 maintains that "the
" powerful mastoid processes of the human skull are the result of
" his erect position ;" and these processes are absent in the orang,
chimpanzee, &c, and are smaller in the gorilla than in man.
Various other structures, which appear connected with man's
erect position, might here have been added. It is very difficult
to decide how far these correlated modifications are the result of
natural selection, and how far of the inherited effects of the
increased use of certain parts, or of the action of one part on
another. No doubt these means of change often co-operate : thus
when certain muscles, and the crests of bone to which they are
attached, become enlarged by habitual use, this shews that
certain actions are habitually performed and must be serviceable.
Hence the individuals which performed them best, would tend
to survive in greater numbers. ^
The free use of the arms and hands, partly the cause and \
partly the result of man's erect position, appears to have led in an I
indirect manner to other modifications of structure. The earlv^/
male forefathers of man were, as previously stated, probably l
furnished with great canine teeth; but as they gradually
acquired the habit of using stones, clubs, or other weapons, for
fighting with their enemies or rivals, they would use their jaws
and teeth less and less. In this case, the jaws, together with the
teeth, would become reduced in size, as we may feel almost sure
from innumerable analogous cases. In a future chapter we
shall meet with a closely parallel case, in the reduction or com-
plete disappearance of the canine teeth in male ruminants,
apparently in relation with the development of their horns ; and
in horses, in relation to their habit of fighting with their incisor
teeth and hoofs.
74 Prof. Broca, La Constitution the Skull/ translated in * Anthro-
des Vertebres caudales, 'La Revue pological Review/ Oct. 1868, p.
d'Anthropologie/ 1871, p. 26, 428. Owen (' Anatomy of Verte-
(separate cop}'). brates/ vol. ii. 1866, p. 551) on the
Tti * On tha Primitive Form of mastoid processes in the higher apea.
54 T lie Descent of Man. Part I,
In the adult male anthropomorphous apes, as Eiitimeyer, 77
and others, have insisted, it is the effect on the skull of the great
development of the jaw-muscles that causes it to differ so greatly
in many respects from that of man, and has given to these
animals " a truly frightful physiognomy." Therefore, as the jaws
and teeth in man's progenitors gradually became reduced in size,
the adult skull would have come to resemble more and more
that of existing man. As we shall hereafter see, a great reduction
of the canine teeth in the males would almost certainly affect the
teeth of the females through inheritance.
As the various mental faculties gradually developed themselves
the brain would almost certainly become larger. No one, I
presume, doubts that the large proportion which the size of
man's brain bears to his body, compared to the same proportion
in the gorilla or orang, is closely connected with his higher
mental powers. We meet with closely analogous facts with
insects, for in ants the cerebral ganglia are of extraordinary
dimensions, and in all the Hymenoptera these ganglia are many
times larger than in the less intelligent orders, such as beetles. 78
On the other hand, no one supposes that the intellect of any
two animals or of any two men can be accurately gauged by the
cubic contents of their skulls. It is certain that there may be
extraordinary mental activity with an extremely small absolute
mass of nervous matter: thus the wonderfully diversified
instincts, mental powers, and affections of ants are notorious^
yet their cerebral ganglia are not so large as the quarter of a
small pin's head. Under this* point of view, the brain of an ant is
one of the most marvellous atoms of matter in the world, perhaps
more so than the brain of a man.
The belief that there exists in man some close relation between
the size of the brain and the development of the intellectual
faculties is supported by the comparison of the skulls of savage
and civilised races, of ancient and modern people, and by the
analogy of the whole vertebrate series. Dr. J. Barnard Davis has
proved, 79 by many careful measurements, that the mean internal
capacity of the skull in Europeans is 92*3 cubic inches; in
Americans 87*5 ; in Asiatics 87*1 ; and in Australians only 81 '9
cubic inches. Professor Broca 80 found that the nineteenth century
77 'Die Grenzen der Thierwelt, vomitoria* 1870, p. 14. My son,
eine Betrachtung zu Darwin's Lehre/ Mr. F. Darwin, dissected for me the
1868, s. 51. cerebral ganglia of the Formica
78 Dujardin, * Annales des Sc. rufa.
Nat,* 3rd series Zoolog. torn. xiv. 79 < Philosophical Transactions,
1850, p. 203. See also Mr. Lowne, 1869, p. 513.
Anatomy and Phys. of the Musca 80 * Les Selections, M, P. Bra.-*,
Chap. II. Manner of Development. 55
skulls from graves in Paris were larger than those from varilta
of the twelfth century, in the proportion of 1484 to 1426 ; an J.
that the increased size, as ascertained by measurements, was
exclusively in the frontal part of the skull — the seat of the
intellectual faculties. Prichard is persuaded that the present
inhabitants of Britain have " much more capacious brain-cases "
than the ancient inhabitants. Nevertheless, it must be admitted
that some skulls of very high antiquity, such as the famous one
of Neanderthal, are well developed and capacious. 81 With
respect to the lower animals, M. E. Lartet, 82 by comparing the
crania of tertiary and recent mammals belonging to the same
groups, has come to the remarkable conclusion that the brain is
generally larger and the convolutions are more complex in the
more recent forms. On the other hand, I have shewn 83 that the
brains of domestic rabbits are considerably reduced in bulk, in
comparison with those of the wild rabbit or hare ; and this may be
attributed to their having been closely confined during many
generations, so that they have exerted their intellect, instincts,
senses and voluntary movements but little.
The gradually increasing weight of the brain and skull inj
man must have influenced the development of the supporting \
spinal column, more especially whilst he was becoming erect \
As this change of position was being brought about, the internal !
pressure of the brain will also have influenced the form of the \
skull ; for many facts show how easily the skull is thus affected. !
Ethnologists believe that it is modified by the kind of cradle in j
which infants sleep. Habitual spasms of the muscles, and a '
cicatrix from a severe burn, have permanently modified the facial
bones. In young persons whose heads have become fixed either
sideways or backwards, owing to disease, one of the two eyes has
changed its position, and the shape of the skull has been altered
Revue d'Anthropologies,' 1873 ; the other hand, with savages, the ave-
see also, as quoted in C. Vogt's rage includes only the more capable
' Lectures on Man/ Eng. transiat. individuals, who have been able to
1864, pp. 88,90. Prichard, 'Phys. survive under extremely hard con-
Hist. of Mankind,' vol. i. 1838, p. ditions of life. Broca thus explains
305. the otherwise inexplicable fact, that
81 In the interesting article just the mean capacity of the skull of
referred to, Prof. Broca has well the ancient Troglodytes of Lozere is
remarked, that in civilised nation*, greater than that of modern French-
the average capacity of the skull men.
must be lowered by the preserva- 82 ' Comptes-rendus des Sciences,'
tion of a considerable number of &c. June 1, 1868.
individuals, weak in mind and body, 8 * ' The Variation of Animals and
who would have been promptly Plants under P^mesticaticn,' voL i,
tiixuinatcd in the savage state. On pp. 124- 129.
$6 The Descent of Man. Paat I
apparently by the pressure of the brain in a new direction. 84
I have shewn that with long-eared rabbits even m trifling a cause
as the lopping forward of one ear drags forward almost ever$
t>one of the skull on that side ; so that the bones on the opposite
side no longer strictly correspond. Lastly, if any animal were
to increase or diminish much in general size, without any change
in its mental powers, or if the mental powers were to be much
increased or diminished, without any great change in the size of
the body, the shape of the skull would almost certainly be
V^jiltered. I infer this from my observations on domestic rabbits,
some kinds of which have become very much larger than the
wild animal, whilst others have retained nearly the same size,
but in both cases the brain has been much reduced relatively to
the size of the body. Now I was at first much surprised on
finding that in all these rabbits the skull had become elongated
or dolichocephalic; for instance, of two skulls of nearly equal
breadth, the one from a wild rabbit and the other from a large
domestic kind, the former was 315 and the latter 4*3 inches in
length. 85 One of the most marked distinctions in different races
of men is that the skull in some is elongated, and in others
rounded; and here the explanation suggested by the case of the
rabbits may hold good; for Welcker finds that short "men incline
more " to brachycephaly, and tall men to dolichocephaly ;" 86 and
tall men may be compared with the larger and longer-bodied
rabbits, all of which have elongated skulls, or are dolicho-
cephalic.
From these several facts we can understand, to a certain
extent, the means by which the great size and more or less
rounded form of the skull have been acquired by man ; and these
are characters eminently distinctive of him in comparison with
the lower animals.
Another most conspicuous difference between man and the
lower animals is the nakedness of his skin. Whales and
porpoises (Cetacea), dugongs (Sirenia) and the hippopotamus are
naked; and this may be advantageous to them for gliding
84 Schaaffhausen gives from Blu- maker, where the head is habitually
menbach and Busch, the cases of the held forward, the forehead become*
spasms and cicatrix, in 'Anthro- more rounded and prominent,
polog. Review/ Oct. 1868, p. 420. " 'Variation of Animals/ &c,
Dr. Jarrold ('Anthropologic* 1808, vol. i. p. 117, on the elongation of
pp. 115, 116) adduces from Camper the skull; p. 119, on the effect of
and from his own observations, cases the lopping of one ear.
of the modification of the skull from * 6 Quoted by Scha&fThausen, in
the head being fixed in an unnatural ' Anthropolog. Review/ Oct. 1868,
position. He believes that in cer- p. 419.
tain trades, such &s that of a shoe-
Chap. II. Manner of Development 57
through the water; nor would it be injurious to them from tho
loss of warmth, as the species, which inhabit the colder regions,
are protected by a thick layer of blubber, serving the same
purpose as the fur of seals and otters. Elephants and rhino-
ceroses are almost hairless ; and as certain extinct species,
which formerly lived under an Arctic climate, were covered with
long wool or hair, it would almost appear as if the existing
species of both genera had lost their hairy covering from exposure
to heat. This appears the more probable, as the elephants in
India which live on elevated and cool districts are more hairy 87
than those on the lowlands. May we then infer that man
became divested of hair from having aboriginally inhabited some
tropical land ? That the hair is chiefly retained in the male sex on
the chest and face, and in both sexes at the junction of all four
limbs with the trunk, favours this inference — on the assumption
that the hair was lost before man became erect ; for the parts
which now retain most hair would then have been most protected
from the heat of the sun. The crown of the head, however,
offers a curious exception, for at all times it must have been one
of the most exposed parts, yet it is thickly clothed with hair.
The fact, however, that the other members of the order of
Primates, to which man belongs, although inhabiting various hot
regions, are well clothed with hair, generally thickest on the upper
surface, 88 is opposed to the supposition that man became naked
through the action of the sun. Mr. Belt believes 89 that within
the tropics it is an advantage to man to be destitute of hair, as
he is thus enabled to free himself of the multitude of ticks (acari)
and other parasites, with which he is often infested, and which
sometimes cause ulceration. But whether this evil is of sufficient
magnitude to have led to the denudation of his body thrcugh
natural selection, may be doubted, since none of the many
quadrupeds inhabiting the tropics have, as far as I know,
acquired any specialised means of relief. The view which seems
to me the most probable is that man, or rather primarily woman,
87 Owen, * Anatomy of Verte- ever, states that in the Gorilla the
orates/ vol. iii. p. 619. hair is thinner on the back, where
88 Isidore Geoffroy St.-Hilaire re- it is partly rubbed off, than on the
marks (* Hist. Nat. Ge'ne'rale,' torn, lower surface.
li. 1859, pp. 215-217) on the head of 8 * The * Naturalist in Nicaragua,'
man being covered with long hair ; 1874, p. 209. As some confirma-
also on the upper surfaces of mon- tion of Mr. Belt's view, I may quote
keys and of other mammals being the following passage from Sir W.
more thickly clothed than the lower Denison (' Varieties of Vice-Regal
surfaces. This has likewise been Life/ vol. i. 1870, p. 440): "It is said
observed by various authors. Prof. *' to be a practice with the Aus-
P. Gervais (' Hist. Nat. des Mam- " tralians, when the vermin get
miteres,' torn. \ 1854, p. 28), how- " troublesome, to singe theixiselvw*.* 1
$8 The Descent of Mat* Pakt I.
became divested of hair for ornamental purposes, as we shall sp*,
under Sexual Selection ; and, according to this belief, it is not
surprising that man should differ so greatly in hairiness from all
other Primates, for characters, gained through sexual selection,
often differ to an extraordinary degree in closely-related forms.
According to a popular impression, the absence of a tail is
eminently distinctive of man; but as those apes which come
nearest to him are destitute of this organ, its disappearance does
not relate exclusively to man. The tail often differs remarkably
in length within the same genus : thus in some species of Hacacus
it is longer than the whole body, and is formed of twenty-four
vertebras; in others it consists of a scarcely visible stump,
containing only three or four vertebra. In some kinds of
baboons there are twenty-five, whilst in the mandrill there are
ten very small stunted caudal vertebrae, or, according to Cuvier, 5 *
sometimes only five. The tail, whether it be long or short, almost
always tapers towards the end ; and this, I presume, results from
the atrophy of the terminal muscles, together with their arteries
and nerves, through disuse, leading to the atrophy of the terminal
bones. But no explanation can at present be given of the great
diversity which often occurs in its length. Here, however, we
are more specially concerned with the complete external dis-
appearance of the tail. Professor Broca has recently shewn 91
that the tail in all quadrupeds consists of two portions, generally
separated abruptly from each other ; the basal portion consists
of vertebrae, more or less perfectly channelled and furnished with
apophyses like ordinary vertebrae ; whereas those of the terminal
portion are not channelled, are almost smooth, and scarcely
resemble true vertebrae. A tail, though not externally visible, is
really present in man and the anthropomorphous apes, and is
constructed on exactly the same pattern in both. In the terminal
portion the vertebrae, constituting the os cocct/x, are quite
rudimentary, being much reduced in size and number. In the
basal portion, the vertebrae are likewise few, are united firmly
together, and are arrested in development ; but they have been
rendered much broader and flatter than the corresponding
vertebrae in the tails of other animals : they constitute what
Broca calls the accessory sacral vertebrae. These are of functional
importance by supporting certain internal parts and in other
ways ; and their modification is directly connected with the erect
90 Mi , St. George Mivart, « Proc. Geoffroy, < Hist. Kat. Gen/ torn. ii.
Zoolog, Soc.' 1865, pp. 562, 583. p. 244.
Dr. J. E.. Gray, l Cat. Brit. Mus. : 9l < Revue d' Anthropologic' 1872;
Skeletons.' Owen, * Anatomy of } La Constitution des Vertebres cata-
Vei tebrates,' vol h. p. 517. Isidore dales.*
Chap.IL Manner of Development 59
or semi-erect attitude of man and the anthropomorphous apes.
This conclusion is the more trustworthy, as Broca formerly held
a different view, which he has now abandoned. The modifica-
tion, therefore, of the basal caudal vertebrae in man and the
higher apes may have been effected, directly or indirectly,
through natural selection.
But what are we to say about the rudimentary and variable
vertebra of the terminal portion of the tail, forming the os coccyx ?
A notion which has often been, and will no doubt again be
ridiculed, namely, that friction has had something to do with
the disappearance of the external portion of the tail, is not
so ridiculous as it at first appears. Dr. Anderson 92 states
that the extremely short tail of Macacus brunneus is formed of
eleven vertebrae, including the imbedded basal ones. The
extremity is tendinous and contains no vertebras; this is suc-
ceeded by five rudimentary ones, so minute that together they
are only one line and a half in length, and these are permanently
bent to one side in the shape of a hook. The free part of the
tail, only a little above an inch in length, includes only four more
small vertebrae. This short tail is carried erect; but about a
quarter of its total length is doubled on to itself to the left ; and
this terminal part, which includes the hook-like portion, serves
" to fill up the interspace between the upper divergent portion
" of the callosities ;" so that the animal sits on it, and thus renders
it rough and callous. Dr. Anderson thus sums up his observa-
tions : " These facts seem to me to have only one explanation ;
" this tail, from its short size, is in the monkey's way when it
" sits down, and frequently becomes placed under the animal
*' while it is in this attitude ; and from the circumstance that it
" does not extend beyond the extremity of the ischial tuberosities
" it seems as if the tail originally had been bent round, by the
" will of the animal, into the interspace between the callosities, to
" escape being pressed between them and the ground, and that
"in time the curvature became permanent, fitting in of itself
" when the organ happens to be sat upon." Under these circum-
stances it is not surprising that the surface of the tail should
have been roughened and rendered callous * and Dr. Murie, 93 who
carefully observed this species in the Zoological Gardens, as well
as three other closely allied forms with slightly longer tails, says
that when the animal sits down, the tail " is necessarily thrust
* to one side of the buttocks ; and whether long or short its root
* is consequently liable to be rubbed or chafed." As we now
e * 4 Proc. Zwnog. Soc.,' 1872, p. •» < Proc. Zwlog. Soc. \Wl% p
310. 786.
60 The Descent of Man. Tabu 1
have evidence that mutilations occasionally produce an inherited
effect, 94 it is not very improbable that in short-tailed monkeys, the
projecting part of the tail, being functionally useless, should after
many generations have become rudimentary and distorted, from
being continually rubbed and chafed. We see the projecting part in
this condition in the Macacus brunneus, and absolutely aborted in
the M. ecaudatus and in several of the higher apes. Finally, then,
as far as we can judge, the tail has disappeared in man and the
anthropomorphous apes, owing to the terminal portion having
been injured by friction during a long lapse of time ; the basal
and embedded portion having been reduced and modified, so as
to become suitable to the erect or semi-erect position.
I have now endeavoured to shew that some of the most
distinctive characters of man have in all probability been
acquired, either directly, or more commonly indirectly, through
natural selection. We should bear in mind that modifications
in structure or constitution, which do not serve to adapt an
organism to its habits of life, to the food which it consumes, or
passively to the surrounding conditions, cannot have been thus
acquired. We must not, however, be too confident in deciding
what modifications are of service to each being: we should
remember how little we know about the use of many parts, or
what changes in the blood or tissues may serve to fit an
organism for a new climate or new kinds of food. Nor must we
forget the principle of correlation, by which, as Isidore Geoffroy
has shewn in the case of man, many strange deviations of
structure are tied together. Independently of correlation, a
change in one part often leads, through the increased or decreased
use of other parts, to other changes of a quite unexpected
nature. It is also well to reflect on such facts, as the wonderful
growth of galls on plants caused by the poison of an insect, and
on the remarkable changes of colour in the plumage of parrots
when fed on certain fishes, or inoculated with the poison of
toads; 95 for we can thus see that the fluids of the system, if
altered for some special purpose, might induce other changes.
We should especially bear in mind that modifications acquired
94 I allude to Dr. Brown-Seq card's inherited effects of mot-mots biting
observations on the transmitted off the barbs of their own tai)-
effect of an operation causing epi- feathers. See also on the general
lepsy in guinea-pigs, and likewise subject * Variation of Animals and
more recently on the analogous Plants under Domestication,' vol.
effects of cutting the sympathetic ii., pp. 22-24.
nerve in the neck. I shall hereafter 85 ' The Variation of Animals and
have occasion to refer to Mr. Salvin ; s Plants under Domestication,' vol. i>
interestijig case of the apparently pp. 280, 282.
Ohap. IL Manner of Development. & *
and continually used during past ages for some useful purpose,
would probably become firmly fixed, and might be long inherited.
Thus a large yet undefined extension may safely be given to
the direct and indirect results of natural selection ; but I now
admit, after reading the essay by Nageli on plants, and the
remarks by various authors with respect to animals, more
especially those recently made by Professor Broca, that in the
earlier editions of my * Origin of Species ' I perhaps attributed
too much to the action of natural selection or the survival oJ
the fittest. I have altered the fifth edition of the ' Origin ' so as to
confine my remarks to adaptive changes of structure ; but I am
convinced, from the light gained during even the last few years
that very many structures which now appear to us useless, will
hereafter be proved to be useful, and will therefore come within
the range of natural selection. Nevertheless, I did not formerly
consider sufficiently the existence of structures, which, as far as
we can at present judge, are neither beneficial nor injurious
and this I believe to be one of the greatest oversights as yet
detected in my work. I may be permitted to say, as some
excuse, that I had two distinct objects in view; firstly, to
shew that species had not been separately created, and secondly,
that natural selection had been the chief agent of change,
though largely aided by the inherited effects of habit, and slightly
by the direct action of the surrounding conditions. I was
not, however, able to annul the influence of my former belief,
then almost universal, that each species had been purposely
created ; and this led to my tacit assumption that every detail
of structure, excepting rudiments, was of some special, though
unrecognised, service. Any one with this assumption in his
mind would naturally extend too far the action of natural
selection, either during past or present times. Some of those
who admit the principle of evolution, but reject natural selec-
tion, seem to forget, when criticising my book, that I had the
above two objects in view ; hence if I have erred in giving to
natural selection great power, which I am very far from
admitting, or in having exaggerated its power, which is in itself
probable, I have at least, as I hope, done good service in aiding
to overthrow the dogma of separate creations.
It is, as I can now see, probable that all organic beings,
including man, possess peculiarities of structure, which neither
are now, nor were formerly of any service to them, and which,
therefore, are of no physiological importance. We know not
what produces the numberless slight differences between tho
individuals of each species, for reversion only carries the
problem a few steps backwards; but each peculiarity must
6.2 TJie Descent of Man, Part I
have had its efficient cause. If these causes, whatever they
may be, were to act more uniformly and energetically during a
lengthened period (and against this no reason can be assigned),
the result would probably be not a mere slight individual
difference, but a well-marked and constant modification, though
one of no physiological importance. Changed structures, which
are in no way beneficial, cannot be kept uniform through natural
selection, though the injurious will be thus eliminated. Uni-
formity of character would, however, naturally follow from the
assumed uniformity of the exciting causes, and likewise from
the free intercrossing of many individuals. During successive
periods, the same organism might in this manner acquire
successive modifications, which would be transmitted in a nearly
uniform state as long as the exciting causes remained the same
and there was free intercrossing. With respect to the exciting
causes we can only say, as when speaking of so-called spon-
taneous variations, that they relate much more closely to the
constitution of the varying organism, than to the nature of the
conditions to which it has been subjected.
Conclusion, — In this chapter we have seen that as man at the
present day is liable, like every other animal, to multiform
individual differences or slight variations, so no doubt were the
early progenitors of man ; the variations being formerly induced
by the same general causes, and governed by the same general
jind complex laws as at present. As all animals tend to multiply •
beyond their means of subsistence, so it must have been with
the progenitors of man; and this would inevitably lead to a
struggle for existence and to natural selection. The latter
process would be greatly aided by the inherited effects of the
increased use of parts, and these two processes would incessantly
react on each other. It appears, also, as we shall hereafter see,
that various unimportant characters have been acquired by man
through sexual selection. An unexplained residuum of change
must be left to the assumed uniform action of those unknown
agencies, which occasionally induce strongly marked and abrupt
deviations of structure in our domestic productions.
Judging from the habits of savages and of the greater number
of the Quadrumana, primeval men, and even their ape-like
progenitors, probably lived in society. With strictly social
animals, natural selection sometimes acts on the individual,
through the preservation of variations which are beneficial to
the community. A community which includes a large number
of well-endowed individuals increases in number, and is victo-
rious over ether less favoured ones; even although each separate
/
{
Chap. II. Manner of Development. 63
membeij gains no advantage over the others of the same com-
munity. Associated insects have thus acquired many remark-
able structures, which are of little or no service to the individual,
such as the pollen-collecting apparatus, or the sting of the
worker^bee, or the great jaws of soldier-ants. With the higher
social animals, I am not aware that any structure has been
modified solely for the good of the community, though some are
of secondary service to it. For instance, the horns of ruminants
and the great canine teeth of baboons appear to have been
acquired by the males as weapons for sexual strife, but they are
used in defence of the herd or troop. In regard to certain
mental powers the case, as we shall see in the fifth chapter, is
wholly different ; for these faculties have been chiefly, or even
exclusively, gained for the benefit of the community, and the
individuals thereof, have at the same time gained an advantage
indirectly.
It has often been objected to such views as the foregoing, that
man is one of the most helpless and defenceless creatures in the
world; and that during his early and less well-developed
condition he would have been still more helpless. The Duke of
Argyll, for instance, insists 96 that "the human frame has
" diverged from the structure of brutes, in the direction of
•' greater physical helplessness and weakness. That is to say, it
" is a divergence which of all others it is most impossible to
" ascribe to mere natural selection." He adduces the naked and
unprotected state of the body, the absence of great teeth or
claws for defence, the small strength and speed of man, and his
slight power of discovering food or of avoiding danger by smell.
To these deficiencies there might be added one still more
serious, namely, that he cannot climb quickly, and so escape-
from enemies. The loss of hair would not have been a great
injury to the inhabitants of a warm country. For we know that the
unclothed Fuegians can exist under a wretched climate. When
we compare the defenceless state of man with that of apes, we
must remember that the great canine teeth with which the latter
are provided, are possessed in their full development by the males
alone, and are chiefly used by them for fighting with their rivals;
yet the females, which are not thus provided, manage to survive.
In regard to bodily size or strength, we do not know whether
man is descended from some small species, like the chimpanzee,
or from one as powerful as the gorilla ; and, therefore, we cannot
say whether man has become larger and stronger, or smaller
•• * Primeval Man, 5 1869, p. 66
64 The Descent of Man. \ Va rt I
and weaker, than his ancestors. We should, however, i bear in
mind that an animal possessing great size, strength, and /ferocity,
and which, like the gorilla, could defend itself from all Enemies,
would not perhaps have become social; and this would most
effectually have checked the acquirement of the higherS mental
qualities, such as sympathy and the love of his fellows. Hence it
might have been an immense advantage to man to have sprung
from some comparatively weak creature.
The small strength and speed of man, his want of natural
weapons, &c, are more than counterbalanced, firstly, by his
intellectual powers, through which he has formed for himself
weapons, tools, &c, though still remaining in a barbarous state,
and, secondly, by his social qualities which lead him to give and
receive aid from his fellow-men. No country in the world abounds
in a greater degree with dangerous beasts than Southern Africa ;
no country presents more fearful physical hardships than the
Arctic regions ; yet one of the puniest of races, that of the
Bushmen, maintains itself in Southern Africa, as do the dwarfed
Esquimaux in the Arctic regions. The ancestors of man were, no
doubt, inferior in intellect, and probably in social disposition, to
the lowest existing savages ; but it is quite conceivable that they
might have existed, or even flourished, if they had advanced in
intellect, whilst gradually losing their brute-like powers, such
as that of climbing trees, &c. Bmt these ancestors would not
have been exposed to any special danger, even if far more
helpless and defenceless than any existing savages, had they
inhabited some warm continent or large island, such as
Australia, New Guinea, or Borneo, which is now the home of the
orang. And natural selection arising from the competition of
tribe with tribe, in some such large area as one of these, together
with the inherited effects of habit, would, under favourable
conditions, have sufficed to raise man to his present high position
in the organic scale.
Ceai\ III. Mental Powers. 65
CHAPTER in.
Comparison of jthe Mental Powers of Man and the
Lower Animals.
The difference in mental power between the highest ape and the lowest
savage, immense — Certain instincts in common — The emotions —
Curiosity — Imitation — Attention — Memory — Imagination — Reason —
Progressive improvement — Tools and weapons used by animals —
Abstraction, self-consciousness — Language — Sense of beauty — Belief in
God, spiritual agencies, superstitions.
We have seen in the last two chapters that man bears in his
bodily structure clear traces of his descent from some lower
form ; but it may be urged that, as man differs so greatly in
his mental power from all other animals, there must be some
error in this conclusion. No doubt the difference in this
respect is enormous, even if we compare the mind of one of the
lowest savages, who has no words to express any number higher
than four, and who uses hardly any abstract terms for common
objects or for the affections, 1 with that of the most highly ,
organised ape. The difference would, no doubt, still remain /
immense, even if one of the higher apes had been improved or
civilised as much as a dog has been in comparison with, its
parent-form, the wolf or jackal. The Fuegians rank amongst
the lowest barbarians; but I was continually struck with
surprise how closely the three natives on board H.M.S. " Beagle,"
who had lived some years in England, and could talk a little .
English, resembled us in disposition and in most of our mental ^
faculties. If no organic being excepting man had possessed any
mental power, or if his powers had been of a wholly different
nature, from those of the lower animals, then we should nevei
have been able to convince ourselves that our high faculties
had been gradually developed. Put it can be shewn that there
is no fundamental difference of this kind. We must also admit \
that there is a much wider interval in mental power between
one of the lowest fishes, as a lamprey or lahcelet, and one of the
higher apes, than between an ape and man ; yet this interval
is filled up by numberless gradations.
Nor is the difference slight in moral disposition between a
barbarian, such as the man described by the old navigator
1 See the evidence on those points, as given by Lubbock, » Prehistorio
Times,' p. 354, &e
66 The Descent of Man. Part 1,
Byron, who dashed his child on the rocks for dropping a basket
of sea-urchins, and a Howard or Clarkson; and in intellect,
between a savage who uses hardly any abstract terms, and a
Newton or Shakspeare. Differences of this kind between the
highest men of the highest races and the lowest savages, are
connected by the finest gradations. Therefore it is possible that
they might pass and be developed into each other.
My object in this chapter is to shew that there is no funda-
mental difference between man and the higher mammals in their
mental faculties. Each division of the subject might have been
extended into a separate essay, but must here be treated briefly.
As no classification of the mental powers has been universally
accepted, I shall arrange my remarks in the order most con-
venient for my purpose ; and will select those facts which have
struck me most, with the hope that they may produce some
effect on the reader.
With respect to animals very low in the scale, I shall give
some additional facts under Sexual Selection, shewing that their
mental powers are much higher than might have been expected.
The variability of the faculties in the individuals of the same
species is an important point for us, and some few illustrations
will here be given. But it would be superfluous to enter into
many details on this head, for I have found on frequent enquiry,
that it is the unanimous opinion of all those who have long
attended to animals of many kinds, including birds, that the
individuals differ greatly in every mental characteristic. In
what manner the mental powers were first developed in the
lowest organisms, is as hopeless an enquiry as how life itself
first originated. These are problems for the distant future, if
they are e^er to be solved by man.
As man possesses the same senses as the lower animals, his
fundamental intuitions must be the same. Man has also some
few instincts in common, as that of self-preservation, sexual love,
the love of the mother for her new-born offspring, the desire
possessed by the latter to suck, and so forth. But man, perhaps,
has somewhat fewer instincts than those possessed by the
animals which come next to him in the series. The orang in
the Eastern islands, and the chimpanzee in Africa, build plat-
forms on which they sleep; and, as both species follow the same
habit, it might be argued that this was due to instinct, but we
cannot feci sure that it is not the result of both animals having
similar wants, and possessing similar powers of reasoning.
These apes, as we may assume, avoid the many poisonous fruits
of the tropics, and man has no such knowledge : but as our
domestic animals, when taken to foreign lands, and when first
Oh a p. III. Mental Powers. 6J
turned out in the spring, often eat poisonous herbs, which they
afterwards avoid, we cannot feel sure that the apes do not learn
from their own experience or from that of their parents wha$
fruits to select. It is, however, certain, as we shall presently sea,
that apes have an instinctive dread of serpents, and probably 01
other dangerous animals. ^
The fewness and the comparative simplicity of the instincts in
the higher animals are remarkable in contrast with those of tho
lower animals. Cuvier maintained that instinct and intelligence
stand in an inverse ratio to each other ; and some have thought
that the intellectual faculties of the higher animals have been
gradually developed from their instincts. But Pouchet, in an
interesting essay, 2 has shewn that no such inverse ratio really
exists. Those insects which possess the most wondeiful instincts
are certainly tho most intelligent. In the vertebrate series, the
least intelligent members, namely fishes and amphibians, do not
possess complex instincts; and amongst mammals the animal
most remarkable for its instincts, namely the beaver, is highly
intelligent, as will be admitted by every one who has read Mr.
Morgan's excellent Work. 3
Although the first dawnings of intelligence, according to Mr.
Herbert Spencer/ have been developed through the multiplicar
tion and co-ordination of reflex actions, and although many of
the simpler instincts graduate into reflex actions, and can hardly
be distinguished from them, as in the case of young animate
sucking, yet the more complex instincts seem to have originated
independently of intelligence. I am, however, very far from
wishing to deny that instinctive actions may lose their fixed and
untaught character, and be replaced by others performed by the
aid of the free will. On the other hand, some intelligent actions,
after being performed during several generations, become con-
verted into instincts and are inherited, as when birds on oceanic
islands learn to avoid man. These actions may then be said
to be degraded in character, for they are no longer performed
through reason or from experience. But the greater number of
the more complex instincts appear to have been gained in a
wholly different manner, through the natural selection of varia-
tions of simpler instinctive actions. Such variations appear to
arise from the same unknown causes acting on the cerebral
organisation, which induce slight variations or individual dif-
ferences in other parts of the body ; and these variations, owing
a ' I/Instincfc chez les Insectes.* 3 ' The American Beaver and Lie
* Revuf des Deux Mondes/ Feb. 1870, Works,' 1868.
p. 6^0. 4 ' The Principles of Psychology,
2nd edit 1870, pp. 418-4-W.
F 2
6$ The Descent of Man. Past I
to our ignorance, are oftca said to arise spontaneously. We can,
I think, come to no other conclusion with respect to the origin of
the more complex instincts, when we reflect on the marvellous
instincts of sterile worker-ants and bees, which leave no off-
spring to inherit the effects of experience and of modified habits.
Although, as we learn from the above-mentioned insects and
the beaver, a high degree of intelligence is certainly compatible
with complex instincts, and although actions, at first learnt
voluntarily can soon through habit be performed with the
quickness and certainty of a reflex action, yet it is not improbable
that there is a certain amount of interference between the
development of free intelligence and of instinct, — which latter
implies some inherited modification of the brain. Little is
known about the functions of the brain, but we can perceive
that as the intellectual powers become highly developed, the
various parts of the brain must be connected by very intricate
channels of the freest intercommunication; and as a conse-
quence, each separate part would perhaps tend to be less well fitted
to answer to particular sensations or associations in a definite
and inherited — that is instinctive— manner. There seems even
to exist some relation between a low degree of intelligence and a
strong tendency to the formation of fixed, though not inherited
habits ; for as a sagacious physician remarked to me, persons
who are slightly imbecile tend to act in everything by routine
or habit ; and they are rendered much happier if this is en-
couraged.
I have thought this digression worth giving, because we may
easily underrate the mental powers of the higher animals, and
especially of man, when we compare their actions founded on the
memory of past events, on foresight, reason, and imagination,
with exactly similar actions instinctively performed by the lower
animals ; in this latter case the capacity of performing such
actions has been gained, step by step, through the variability of
the mental organs and natural selection, without any conscious
intelligence on the part of the animal during each successive
generation. No doubt, as Mr. Wallace has argued, 6 much of the
intelligent work done by man is due to imitation and not to
reason; but there is this great difference between his actions
and many of those performed by the lower animals, namely, that
man cannot, on his first trial, make, for instance, a stone hatchet
or a canoe, through his power of imitation. He has to learn his
work by practice ; a beaver, on the other hand, can make its
dam or canal, and a bird its nest, as. well, or nearly as well, and
*.* Contributions to the Theojy of Matural Selection,' 1870, j*. 212,
Chap. III. Mental Powers,
a spider its wonderful web, quite as well/ the first time it tries
as when old and experienced.
. To return to our immediate subject : tho lower animals, like
man, manifestly feel pleasure and pain, happiness and misery.
Happiness is never better exhibited than by young animals, sucb
as puppies, kittens, lambs, &c, when playing together, like our
own children. Even insects play together, as has been described
by that excellent observer, P. Huber, 7 who saw ants chasing and
pretending to bite each other, like so many puppies.
Tho fact that the lower animals are excited by the same
emotions as ourselves is so well established, that it will not be
necessary to weary the reader by many details. Terror acts in
the same manner on them as on us, causing the muscles to
tremble, the heart to palpitate, the sphincters to be relaxed, and
the hair to stand on end. Suspicion, the offspring of fear, is
eminently characteristic of most wild animals. Ifc is, I think,
impossible to read the account given by Sir E. Tennent, of the
behaviour of the female elephants, used as decoys, without
admitting that they intentionally practise deceit, and well know
what they are about. Courage and timidity are extremely
variable qualities in the individuals of the same species, as is
plainly seen in our dogs. Some dogs and horses are ill-tempered,
and easily turn sulky ; others are good-tempered ; and these
qualities are certainly inherited. Every one knows how liable
animals are to furious rage, and how plainly they show it.
Many, and probably true, anecdotes have been published on the
long-delayed and artful revenge of various animals. The
accurate Eengger, and Brehm 8 state that the American and
African monkeys which they kept tame, certainly revenged
themselves. Sir Andrew Smith, a zoologist whose scrupulous
accuracy was known to many persons, told me the following
story of which he was himself an eye-witness ; at the Cape
of Good Hope an officer had often plagued a certain baboon,
and the animal, seeing him approaching one Sunday for
parade, poured water into a hole and hastily made some thick
mud, which he skilfully dashed over the officer as he passed
by, to the amusement of many bystanders. For long after-
wards the baboon rejoiced and triumphed whenever he saw his
victim.
6 For the evidence on this % All the following statements,
kead, see Mr. J. Traherne Mog- given on the authority of these two
gridge's most interesting work, naturalists, are taken from Rengger'a
4 Harvesting Ants and Trap-doer * Naturgesch. der S'augethiere voo
Spiders/ 1873, p. 126, 128. , Paraguay/ 1830, s. 41-57, and froaa
7 * Recherches sur les MoDurs des Brehm's 'Thierleben/ B. i ». 10-37
Fourmis/ 1810, p. 173.
7® ~ The Descent of Man, Past I,
The love of a dog for his master is notorious; as an old
writer quaintly says, 9 " A dog is the only thing on this earth
" that luvs you more than he luvs himself/*
In the agony of death a dog has been known to caress
his master, and every one has heard of the dog suffering
under vivisection, who licked the hand of the operator; this
man, unless the operation was fully justified by an increase
of our knowledge, or unless he had a heart of stone, must have
felt remorse to the last hour of his life.
As Whewell 10 has well asked, " who that reads the touching
" instances of maternal affection, related so often of the women of
" ail nations, and of the females of all animals, can doubt that the
" principle of action is the same in the two cases ? " We see mater-
nal affection exhibited in the most trifling details ; thus Rengger
observed an American monkey (a Cebus) carefully driving away
the flies which plagued her infant; and Duvaucel saw a
Hylobates washing the faces of her young ones in a stream. So
intense is the grief of female monkeys for the loss of their
young, that it invariably caused the death of certain kinds kept
under confinement by Brehm in N. Africa. Orphan monkeys
were always adopted and carefully guarded by the other monkeys,
both males and females. One female baboon had so capacious
a heart that she not only adopted young monkeys of other
species, but stole young dogs and cats, which she continually
carried about. Her kindness, however, did not go so far as to
share her food with her adopted offspring, at which Brehm was
surprised, as his monkeys always divided everything quite
fairly with their own young ones. An adopted kitten scratched
this affectionate baboon, who certainly had a fine intellect, for
she was much astonished at being scratched, and immediately
examined the kitten's feet, and without more ado bit off the
claws. 11 In the Zoological Gardens, I heard from the keeper
that an old baboon (0. chacma) had adopted a Bhesus monkey;
but when a young drill and mandrill were placed in the cage,
she seemed to perceive that these monkeys, though distinct
species, were her nearer relatives, for she at once rejected the
Bhesus and adopted both of them. The young Bhesus, as I saw,
was greatly discontented at being thus rejected, and it would,
like a naughty child, annoy and attack the young drill and mandrill
9 Quoted by Dr. Lauder Lindsay, 72), disputes the possibility of this
in his ' Physiology of Mind in the act as described by Brehm, for the
Lower Animals ;' ' Journal of Mental sake of discrediting my work.
Science/ April 1871, p. 38. Therefore I tried, and found that I
10 * Bridgewater Treatise/ p. 263. could readily seize with my own
11 A crit^, without any grounds teeth the sharp little claws of a
('Quarterly Review.' July 1871, p. kitten nearly rive weeks old.
Chap, III. Mental Powers. 71
whenever it could do so with safety ; this conduct exciting great
indignation in the old baboon. Monkeys will also, according to
Brehm, defend their master when attacked by any one, as well as
dogs to whom they are attached, from the attacks of other dogs.
But we here trench on the subjects of sympathy and fidelity, to
which I shall recur. Some of Brehm's monkeys took much
delight in teasing a certain old dog whom they disliked, as
well as other animals, in various ingenious ways.
Most of the more complex emotions are common to the
higher animals and ourselves. Every one has seen how jealous
a dog is of his master's affection, if lavished on any other
creature; and I have observed the same fact with monkeys.
This shews that animals not only love, but have desire to be
loved. Animals manifestly feel emulation. They love appro-
bation or praise; and a dog carrying a basket for his master
exhibits in a high degree self-complacency or pride. There can,
I think, be no doubt that a dog feels shame, as distinct from
fear, and something very like modesty when begging too often
for food. A great dog scorns the snarling of a little dog, and
this may be called magnanimity. Several observers have stated
that monkeys certainly dislike being laughed at; and they
sometimes invent imaginary offences. In the Zoological Gardens
I saw a baboon who always got into a furious rage when his
keeper took out a letter or book and read it aloud to him ; and
his rage was so violent that, as I witnessed on one occasion, he
bit his own leg till the blood flowed. Dogs show what may be
fairly called a sense of humour, as distinct from mere play ; if
a bit of stick or other such object be thrown to one, he will often
carry it away for a short distance; and then squatting down
with it on the ground close before him, will wait until his
master comes quite close to take it away. The dog will then
seize it and rush away in triumph, repeating the same manoeuvre,
and evidently enjoying the practical joke.
We will now turn to the more intellectual emotions and
faculties, which are very important, as forming the basis for the
development of the higher mental powers. Animals manifestly
enjoy excitement, and suffer from ennui, as may be seen with
dogs, and, according to Eengger, with monkeys. All animals
feel Wonder, and many exhibit Curiosity. They sometimes
suffer from this latter quality, as when the hunter plays antics
and thus attracts them ; I have witnessed this with deer, and so
it is with the wary chamois, and with some kinds of wild-ducks.
Brehm gives a curious account of the instinctive dread, which
his monkeys exhibited, for snakes; but their curiosity was
so great that they could not desist from occasionally satiating
/2 The Descent of Man. Pabt 1
tlieir horror in a most human fashion, by lifting up the lid of the
box in which the snakes were kept. I was so much surprised at
his account, that I took a stuffed and coiled-up snake into the
monkey-house at the Zoological Gardens, and the excitement
thus caused was one of the most curious spectacles which I ever
beheld. Three species of Cercopithecus were the most alarmed ;
they dashed about their cages, and uttered sharp signal cries of
danger, which were understood by the other monkeys. A few
young monkeys and one old Anubis baboon alone took no notice
of the snake. I then placed the stuffed specimen on the ground
in one of the larger compartments. After a time all the monkeys
collected round it in a large circle, and staring intently,
presented a most ludicrous appearance. They became extremely
nervous ; so that when a wooden ball, with which they were
familiar as a plaything, was accidentally moved in the straw,
under which it was partly hidden, they all instantly started
away. These monkeys behaved very differently when a dead
fish, a mouse, 12 a living turtle, and other new objects were placed
in their cages; for though at first frightened, they soon
approached, handled and examined them. I then placed a live
snake in a paper bag, with the mouth loosely closed, in one of
the larger compartments. One of the monkeys immediately
approached, cautiously opened the bag a little, peeped in, and
instantly dashed away. Then I witnessed what Brehm has
described, for monkey after monkey, with head raised high and
turned on one side, could not resist taking a momentary peep
into the upright bag, at the dreadful object lying quietly at the
bottom. It would almost appear as if monkeys had some
notion of zoological affinities, for those kept by Brehm exhibited
a strange, though mistaken, instinctive dread of innocent lizards
and frogs. An orang, also, has been known to be much alarmed
at the first sight of a turtle. 13
The principle of Imitation is strong in man, and especially, as
I have myself observed, with savages. In certain morbid states
of the brain this tendency is exaggerated to an extraordinary
degree ; some hemiplegic patients and others, at the commence-
ment of inflammatory softening of the brain, unconsciously
imitate every word which is uttered, whether in their own or in
a foreign language, and every gesture or action which is per-
formed near them. 14 Desor 15 has remarked that no animal
12 I have given a short account of Mammalia/ 1841, p. 405.
cf their behaviour on this occasion 14 Dr. Bateman * On Aphasia,
in my 'Expression of the Emotions,' 1870, p. 110.
p. 43. 15 Quoted by Vogt, 'Memoire sm
w W. C. L. Martin, « Nat. Hist, les Microcephales,' 1867, p. 168.
Ship. III. Mental Powers. 73
voluntarily imitates an action performed by man, until in the
ascending scale we come to monkeys, which are well known to
l>e ridiculous mockers. Animals, however, sometimes imitate
each other's actions : thus two species of wolves, which had been
reared by dogs, learned to bark, as does sometimes the jackal, 1 ' 1
but whether this can be called voluntary imitation is another
question. Birds imitate the songs of their parents, and some-
times of other birds ; and parrots are notorious imitators of any
sound which they often hear. Dureau de la Malle gives an
account " of a dog reared by a cat, who learnt to imitate the
well-known action of a cat licking her paws, and thus washing
her ears and face; this was also witnessed by the celebrated
naturalist Audouin. I have received several confirmatory ac-
counts ; in one of these, a dog had not been suckled by a cat,
but had been brought up with one, together with kittens, and
had thus acquired the above habit, which he ever afterwards
practised during his life of thirteen years. Dureau de la Malle's
dog likewise learnt from the kittens to play with a ball by roll-
ing it about with his fore paws, and springing on it. A corre-
spondent assures me that a cat in his house used to put her paws
into jugs of milk having too narrow a mouth for her head. A
kitten of this cat soon learned the same trick, and practised it
ever afterwards, whenever there was an opportunity.
The parents of many animals, trusting to the principle of
imitation in their young, and more especially to their instinctive
or inherited tendencies, may be said to educate them. We see
this when a cat brings a live mouse to her kittens; and Dureau
de la Malle has given a curious account (in the paper above
quoted) of his observations on hawks which taught their young
dexterity, as well as judgment of distances, by first dropping
through the air dead mice and sparrows, which the young
generally failed to catch, and then bringing them live birds
and letting them loose.
Hardly any faculty is more important for the intellectual
progress of man than Attention, Animals clearly manifest this
power, as when a cat watches by a hole and prepares to spring
on its prey. Wild animals sometimes become so absorbed when
thus engaged, that they may be easily approached. Mr. Bartlett
has given me a curious proof how variable this faculty is in
monkeys. A man who trains monkeys to act in plays, used to
purchase common kinds from the Zoological Society at the price
of five pounds for each ; but he offered to give double the price,
16 « The Variation of Animals aad 17 *Annales d«s Sc. Nat.' (1st
Plants under Domestication,' vol. i. Series), torn, xxii p. 397.
d. 27.
74 The Descent of Man Past I.
if lie might keep three or four of them for a few days, in order
to select one. When asked how he could possibly learn so soon,
whether a particular monkey would turn out a good actor, he
answered that it all depended on their power of attention. Jf,
when he was talking and explaining anything to a monkey, its
attention was easily distracted, as by a fly on the wall or other
trifling object, the case was hopeless. If he tried by punishment
to make an inattentive monkey act, it turned sulky. On the
other hand, a monkey which carefully attended to him could
always be trained.
It is almost superfluous to state that animals have excellent
Memories for persons and places. A baboon at the Cape of Good
Hope, as I have been informed by Sir Andrew Smith, recognised
him with joy after an absence of nine months. I had a dog who
was savage and averse to all strangers, and I purposely tried his
memory after an absence of five years and two days. I went
near the stable where he lived, and shouted to him in my old
manner ; he shewed no joy, but instantly followed me out walk-
ing, and obeyed me, exactly as if I had parted with him only
half an hour before. A train of old associations, dormant during
five years, had thus been instantaneously awakened in his mind.
Even ants, as P. Huber I8 has clearly shewn, recognised their
fellow-ants belonging to the same community after a separation
of four months. Animals can certainly by some means judge of
the intervals of time between recurrent events.
The Imagination is one of the highest prerogatives of man.
By this faculty he unites former images and ideas, independently ,
of the will, and thus creates brilliant and novel fesults. A poet,
as Jean Paul Richter remarks, 19 " who must reflect whether he
"shall make a character say yes or no — to the devil with him;
" he is only a stupid corpse." Dreaming gives us the best notion
of this power ; as Jean Paul again says, " The dream is an in-
" voluntary art of poetry." The value of the products of our
imagination depends of course on the number, accuracy, and
clearness of our impressions, on our judgment and taste in
selecting or rejecting the involuntary combinations, and to a
certain extent on our power of voluntarily combining them. As
dogs, cats, horses, and probably all the higher animals, even
birds 20 have vivid dreams, and this is shewn by their movements
and the sounds uttered, we must admit that they possess some
19 l Les Moeurs des Fourmis,' 2° Dr. Jerdon, * Birds of India,
1810, p. 150. vol. i. 1862, p. xxi. Houzeau say*
19 Quoted in Dr. Maudsley's ' Phy * that his parokeets and canary-birda
Biology and Pathology of Mind,' 186S, dreamt: * Facultes Mentales*' torn
pp. 19,220. ii. p. 136.
£hap. III. Mental Powers, 75
bower of imagination. There must be something special, wliich
tauses dogs to howl in the night, and especially during moonlight,
in that remarkable and melancholy manner called baying.
All dogs do not do so ; and, according to Houzeau, 21 they do not
then look at the moon, but at some fixed point near the horizon.
Houzeau thinks that their imaginations are disturbed by the
vague outlines of the surrounding objects, and conjure up before
them fantastic images : if this be so, their feelings may almost
be called superstitious.
Of all the faculties of the human mind, it will, I presume, be
admitted that Beason stands at the summit. Only a few persons
now dispute that animals possess some power of reasoning.
Animals may constantly be seen to pause, deliberate, and resolve.
It is a significant fact, that the more the habits of any particular
animal are studied by a naturalist, the more he attributes to
reason and the less to unlearnt instincts. 22 In future chapters
we shall see that some animals extremely low in the scale appar-
ently display a certain amount of reason. No doubt it is often
difficult to distinguish between the power of reason and that of
instinct For instance, Dr. Hayes, in his work on ' The Open
Polar Sea/ repeatedly remarks that his dogs, instead of continu-
ing to draw the sledges in a compact body, diverged and separ-
ated when they came to thin ice, so that their weight might be
more evenly distributed. This was often the first warning
which the travellers received that the ice was becoming thin and
dangerous. Now, did the dogs act thus from the experience of
each individual, or from the example of the older and wiser dogs,
or from an inherited habit, that is from instinct ? This instinctj
may possibly have arisen since the time, long ago, when dogs
were first employed by the natives in drawing their sledges ; or
the Arctic wolves, the parent-stock of the Esquimaux dog, may
have acquired an instinct, impelling them not to attack their
prey in a close pack, when on thin ice.
We can only judge by the circumstances under which actions
are performed, whether they are due to instinct, or to reason, or
to the mere association of ideas: this latter principle, however,
is intimately connected with reason. A curious case has been
given by Prof. Mobius, 23 of a pike, separated by a plate of glass
from an adjoining aquarium stocked with fish,- and who often
dashed himself with such violence against the glass in trying to
21 * Faculty Mentales des Ani- I cannot help thinking, however,
maux,' 1872, torn, ii, p. 181. that he goes too far in underrating
22 Mr. L. H. Morgan's work on the power of Instinct.
* The American Beaver,' 1868, offers a * 'Die Bewegungen der Thiere,
b goo<J illustration of this remark. &c, 1873, p. 11.
76 The Descent of Mail. Part L
eatch the other fishes, that he was sometimes completely
Btuimed. The pike went on thus for three months, but at last
learnt caution, and ceased to do so. The plate of glass was then
removed, but the pike would not attack these particular fishes,
though he would devour others which were afterwards intro-
duced ; so strongly was the idea of a violent shock associated
in his feeble mind with the attempt on his former neighbours.
If a savage, who had never seen a large plate-glass window,
were to dash himself even once against it, he would for a long
time afterwards associate a shock with a window-frame ; but
very differently from the pike, he would probably reflect on the
nature of the impediment, and be cautious under analogous
circumstances. Now with monkeys, as we shall presently see, a
painful or merely a disagreeable impression, from an action once
performed, is sometimes sufficient to prevent the animal from
repeating it. If we attribute this difference between the monkey
and the pike solely to the association of ideas being so much
stronger and more persistent in the one than the other, though
the pike often received much the more severe injury, can we
maintain in the case of man that a similar difference implies the
possession of a fundamentally different mind ?
Houzeau relates 24 that, whilst crossing a wide and arid plain
in Texas, his two dogs suffered greatly from thirst, and that
between thirty and forty times they rushed down the hollows
to search for water. These hollows were not valleys, and there
were no trees in them, or any other difference in the vegetation,
and as they were absolutely dry there could have been no
smell of damp earth. The dogs behaved as if they knew that
a dip in the ground offered them the best chance of finding
water, and Houzeau has often witnessed the same behaviour in
other animals.
I have seen, as I daresay have others, that when a small
object is thrown on the ground beyond the reach of one of the
elephants in the Zoological Gardens, he blows through his trunk
on the ground beyond the object, so that the current reflected
on all sides may drive the object within his reach. Again a well-
known ethnologist, Mr. Westropp, informs me that he observed in
Vienna a bear deliberately making with his paw a current in
some water, which was close to the bars of his cage, so as to
draw a piece of floating bread within his reach. These actions of
the elephant and bear can hardly be attributed to instinct or
inherited habit, as they would be of little use to an animal in a
state of nature. Now, what is the difference between such
74 'Facult&s Mentales des Ammaux,' 1872, torn. ii. p. 265.
Obaj. III. Mental Powers. 77
actions, when performed by an uncultivated man, and by one of
the higher animals ?
The savage and the dog have often found water at a low level,
and the coincidence under such circumotances has become asso-
ciated in their minds. A cultivated man would perhaps make
some general proposition on the subject ; but from all that we
know of savages it is extremely doubtful whether they would do
so, and a dog certainly would not. But a savage, as well as a
dog, would search in the same way, though frequently dis-
appointed ; and in both it seems to be equally an act of reason,
whether or not any general proposition on the subject is
consciously placed before the mind. 26 The same would apply to
the elephant and the bear making currents in the air or water.
The savage would certainly neither know nor care by what law
the desired movements were effected; yet his act would bo
guided by a rude process of reasoning, as surely as would a
philosopher in his longest chain of deductions. There would no
doubt be this difference between him and one of the higher
animals, that he would take notice of much slighter circum-
stances and conditions, and would observe any connection
between them after much less experience, and this would be of
paramount importance. I kept a daily record of the actions of
one of my infants, and when he was about eleven months old,
and before he could speak a single word, I was continually
struck with the greater quickness, with which all sorts of objects
and sounds were associated together in his mind, compared with
that of the most intelligent dogs I ever knew. But the higher
animals differ in exactly the same way in this power of associa-
tion from those low in the scale, such as the pike, as well as in
that of drawing inferences and of observation.
The promptings of reason, after very short experience, are well
shewn by the following actions of American monkeys, which
stand low in their order. Eengger, a most careful observer,
states that when he first gave eggs to his monkeys in Paraguay,
they smashed them, and thus lost much of their contents ; after-
wards they gently hit one end against some hard body, and
picked off the bits of shell with their fingers. After cutting
themselves only once with any sharp tool, they would not touch
it again, or would handle it with the greatest caution. Lumps
of sugar were often given them wrapped up in paper; and
sa Prof. Huxley has analysed with See his article, * Mr. Darwin's
Admirable clearness the mental steps Critics,' in the * Contemporary Re-
by which a man, as well as a dog, view,' Nov. 1871, p. 462, and in his
arrives at a conclusion in a case * Critiques and Essays,' 1873, p. 270.
*nalogc!is to that given in my text
7 8 The Descent jf Man. Pam? ;
Hengger sometimes put a live wasp in the paper, so that in
hastily unfolding it they got stung ; after this had once happened,
they always first held the packet to their ears to detect any
movement within. 28
The following cases relate to dogs. Mr. Colquhoun 27 winged
two wild-ducks, which fell on the further side of a stream ; his
retriever tried to bring over both at once, but could not succeed ;
she then, though never before known to ruffle a feather,
deliberately killed one, brought over the other, and returned
for the dead bird. Col. Hutchinson relates that two partridges
were shot at once, one being killed, the other wounded; the
latter ran away, and was caught by the retriever, who on her
return came across the dead bird; "she stopped, evidently
*' greatly puzzled, and after one or two trials, finding she could
" not take it up without permitting the escape of the winged
" bird, she considered a moment, then deliberately murdered it
" by giving it a severe crunch, and afterwards brought away
"both together. This was the only known instance of her
" ever having wilfully injured any game." Here we have reason
though not quite perfect, for the retriever might have brought
the wounded bird first and then returned for the dead one, as in
the case of the two wild-ducks. I give the above cases, as
resting on the evidence of two independent witnesses, and
because in both instances the retrievers, after deliberation,
broke through a habit which is inherited by them (that of not
killing the game retrieved), and because they shew how strong
their reasoning faculty must have been to overcome a fixed
habit.
I will conclude by quoting a remark by the illustrious
Humboldt. 28 " The muleteers in S. America say, ' I will not give
" ' you the mule whose step is easiest, but la mas rational, — the
"'one that reasons best;'" and as he adds, "this popuku ispres-
" sion, dictated by long experience, combats the system of
" animated machines, better perhaps than all the arguments of
" speculative philosophy." Nevertheless some writers even yet
deny that the higher animals possess a trace of reason; and they
endeavour to explain away, by what appears to be mere
Terbiage, 29 all such fact? as those above given.
26 Mr. Belt, in his most interest- p. 45. Col. Hutchinson on * Dog
in£ work, « The Naturalist in Ni- Breaking,' 1850, p. 46.
caragua,' 1874 (p. 119), likewise 28 * Personal Narrative,* Eng.
describes Various actions of a tamed translat., vol. iii. p. 106.
Cebus, which, I think, clearly shew i9 I am glad to find that so acute
that this animal possessed some a reasoner as Mr. Leslie Stephen
reasoning power. ('Darwinism and Divinity, Essays
"•The Moor and the Loch,* m Free-thinking,* 1873, p. 80), in
Chain III. Mental Powers. 79
It has, I think, now been shewn that man and the higher
animals, especially the Primates, have some few instincts in
common. All have the same senses, intuitions, and sensations, —
similar passions, affections, and emotions, even the more complex
ones, such as jealousy, suspicion, emulation, gratitude, and
magnanimity ; they practise deceit and are revengeful ; they are
sometimes susceptible to ridicule, and even have a sense of
humour ; they feel wonder and curiosity ; they possess the samo .
faculties of imitation, attention, deliberation, choice, memory, |
imagination, the association of ideas, and reason, though in very I
different degrees. The individuals of the same species graduate
in intellect from absolute imbecility to high excellence. They
are also liable to insanity, though far less often than in the caso
of man. 30 Nevertheless, many authors have insisted that man is
divided by an insuperable barrier from all the lower animals in
his mental faculties. I formerly made a collection of above a
score of such aphorisms, but they are almost worthless, as their
wide difference and number prove the difficulty, if not the im-
possibility, of the attempt. It has been asserted that man alone
is capable of progressive improvement ; that he alone makes use
of tools or fire, domesticates other animals, or possesses property;
that no animal has the power of abstraction, or of forming
general concepts, is self-conscious and comprehends itself ; that
no animal employs language; that man alone has a sense of
beauty, is liable to caprice, has the feeling of gratitude, mystery,
&c. ; believes in God, or is endowed with a conscience. I will
hazard a few remarks on the more important and interesting of
these points.
Archbishop Sumner formerly maintained 31 that man alone is
capable of progressive improvement. That he is capable of
incomparably greater and more rapid improvement than is any
other animal, admits of no dispute; and this is mainly
due to his power of speaking and handing down his acquired
knowledge. With animals, looking first to the individual, every
one who has had any experience in setting traps, knows that
speaking of the supposed impassable " tures. It is difficult to under-
barrier between the minds of man " stand how anybody who has ever
and the lower animals, says, " The " kept a dog, or seen an elephant,
'* distinctions, indeed, which have " can have any doubts as to an
*' been drawn, seem to us to rest " animal's power of performing the
a upon no better foundation than a " essential processes of reasoning."
rt great many other metaphysical 30 See * Madness in Animals,' by
44 distinctions ; that is, the assump- Dr. W. Lauder Lindsay, in * Journal
u tion that because you can give of Mental Science,* July 1871.
M two things different names, they 81 Quoted by Sir G. Lyell, * Anti?
u must therefore have different na- quity of Man,' p. 497.
80 The Descent of Man. Tabt L
young animals can be caught much more easily than old ones ;
and they can be much more easily approached by an enemy.
Even with respect to old animals, it is impossible to catch many in
the same place and in the same kind of trap, or to destroy them
by the same kind of poison ; yet it is improbable that all should
have partaken of the poison, and impossible that all should have
been caught in a trap. They must learn caution by seeing their
brethren caught or poisoned. In North America, where the fur-
bearing animals have long been pursued, they exhibit, according
to the unanimous testimony of all observers, an almost incredible
amount of sagacity, caution and cunning ; but trapping has been
there so long carried on, that inheritance may possibly have come
into play. I have received several accounts that when telegraphs
are first set up in any district, many birds kill themselves by
flying against the wires, but that in the course of a very few
years they learn to avoid this danger, by seeing, as it would
appear, their comrades killed. 32
If we look to successive generations, or to the race, there is no
doubt that birds and other animals gradually both acquire and
lose caution in relation to man or other enemies; 33 and this
caution is certainly in chief part an inherited habit or instinct,
but in part the result of individual experience. A good observer,
Leroy, 34 states, that in districts where foxes are much hunted,
the young, on first leaving their burrows, are incontestably much
more wary than the old ones in districts where they are not much
disturbed.
Our domestic dogs are descended from wolves and jackals, 38
and though they may not have gained in cunning, and may have
lost in wariness and suspicion, yet they have progressed in
certain moral qualities, such as in affection, trust-worthiness,
temper, and probably in general intelligence. The common rat
lias conquered and beaten several other species throughout
Europe, in parts of North America, New Zealand, and recently in
Formosa, as well as on the mainland of China. Mr. Swinhoe, 3 *
who describes these two latter cases, attributes the victory of the
common rat over the large Mus coninga to its superior cunning ;
and this latter quality may probably be attributed to the habitual
•* For additional evidence, with ** * Lettres Phil, sur ^Intelligence
details, see M. Houzeau, ' Les des Aniniaux,' nouvelle edit. i802,
Faculte* Mentales,' torn. ii. 1872, p. 86.
p. 147. 35 See the evidence on this head
3 * See, with respect to birds on in chap. i. vol. i. ' On the Variation
oceanic islands, my * Journal of of Animals and Plants under Do*
Researches during the voyage of the mestication.'
" Beagle,"' 1845, p. 398. * Origin M 'Proc. Zoolog. Soc' 18*34 p.
of Species,' 5th edit. p. 260. 186.
Chap. III. Mental Powers. 81
exercise of all its faculties in avoiding extirpation by man, as
well as to nearly all the less cunning or weak-minded rats having
been continuously destroyed by him. It is, however, possible
that the success of the common rat may be due to its having
possessed greater cunning than its fellow-species, before it
became associated with man. To maintain, independently of any
direct evidence, that no animal during the course of ages has
progressed in intellect or other mental faculties, is to beg the
question of the evolution of species. We have seen that, ac-
cording to Lartet, existing mammals belonging to several orders
have larger brains than their ancient tertiary prototypes.
It has often been* said that no animal uses any tool ; but
the chimpanzee m a state of nature cracks a native fruit, some-
what like a walnut, with a stone.* 7 Eengger 38 easily taught an
American monkey thus to break open hard palm-nuts ; and
afterwards of its own accord, it used stones to open other kinds
of nuis, as well as boxes. It thus also removed the soft rind of
fruit that had a disagreeable flavour. Another monkey was\
taught^ to open the lid of a large box with a stick, and after-
wards it used the stick as a lever to move heavy bodies ; and I
have myself seen a young orang put a stick into a crevice, slip
his hand to tne other end, and use it in the proper manner as a
lever. The tamed elephants in India are well known to break
off branches ot trees and use them to drive away the flies ; and
this same act has been observed in an elephant in a state of
nature. 39 I have seen a young orang, when she thought she was
going to be whipped, cover and protect herself with a blanket or
straw. In these several cases stones and sticks were employed
as implements ; but they are likewise used as weapons. Brehm 44
states, on the authority of the well-known traveller Schimper,
that in Abyssinia when the baboons belonging to one species
(0. gelada) descend in troops from the mountains to plunder the
fields, they sometimes encounter troops of another species
(<7. hamadryas), and then a fight ensues. The Geladas roll
down great stones, which the Hamadryas try to avoid, and then
both species, making a great uproar, rush furiously against each
other. Brehm, when, accompanying the Duke of Coburg-Gotha,
aided in an attack with fire-arms on a troop of baboons in the
pass of Mensa in Abyssinia. The baboons in return rolled so
many stones down the mountain, some as large as a man's head,
that the attackers had to beat a hasty retreat; and the pass waa
37 Savage and Wyman in ' Boston 1830, s. 51-56.
Journal of .Nat. Hist.' vol. iv. 1843- 89 The * Indian Field,' March 4
44, p. 383. 1871.
38 * Saugethiere von Paraguay,' *• * Thierleben/ B. i. 9. 79, 82.
Q
82 The Descent of Man. PahtI.
actually closed for a time against the caravan. It deserves
notice that these baboons thus acted in concert. Mr. Wallace 41
on three occasions saw female orangs, accompanied by their
young, " breaking off branches and the great spiny fruit of the
w ■ Durian tree, with every appearance of rage ; causing such a
*' shower of missiles as effectually kept us from approaching too
" near the tree." As I have repeatedly seen, a chimpanzee will
throw any object at hand at a person who offends him ; and the
before mentioned baboon at the Cape of Good Hope prepared
mud for the purpose.
In the Zoological Gardens, a monkey, which had weak teeth,
used to break open nuts with a stone ; and I was assured by the
keepers that after using the stone, he hid it in the straw, and
would not let any other monkey touch it. Here, then, we have
the idea of property ; but this idea is common to every dog with
a bone, and to most or all birds with their nests.
The Duke of Argyll 42 remarks, that the fashioning of an
implement for a special purpose is absolutely peculiar to man ;
and he considers that this forms an immeasurable gulf between
him and the brutes. This is no doubt a very important dis-
tinction ; but there appears to me much truth in Sir J. Lubbock's
suggestion, 43 that when primeval man first used flint-stones for
any purpose, he would have accidentally splintered them, and
would then have used the sharp fragments. From this step it
would be a small one to break the flints on purpose, and not a
very wide step to fashion them rudely. This latter advance,
however, may have taken long ages, if we may judge by the
immense interval of time which elapsed before the men of the
neolithic period took to grinding and polishing their stone tools.
In breaking the flints, as Sir J. Lubbock likewise remarks,
sparks would have been emitted, and in grinding them heat
would have been evolved : thus the two usual methods of
" obtaining fire may have originated." The nature of fire would
have been known in the many volcanic regions where lava
occasionally flows through forests. The anthropomorphous
apes, guided probably by instinct, build for themselves tem-
porary platforms ; but as many instincts are largely controlled
by reason, the simpler ones, such as this of building a platform,
might readily pass into a voluntary and conscious act. The
orang is known to cover itself at night with the leaves of the
Pandanus ; and Brehm states that one of his baboons used to
protect itself from the heat of the sun by throwing a straw-mat
41 « The Malay Archipelago,' vol. 145, 147.
L 1869, p. 87. 43 l Prehistoric Times,' 1865, p.
** < Primeval Man,' 1869, pp. 473, &c.
Chap. III. Mental Powers. S3
over its head In these several habits, we probably see the first
stops towards some of the simpler arts, such as rude architecture
and dress, as they arose amongst the early progenitors of man.
Abstraction, General Conceptions, Self -consciousness, Mental
individuality. — It would be very difficult for any one with even
much more knowledge than I possess, to determine how far
animals exhibit any traces of these high mental powers. This
difficulty arises from the impossibility of judging what passes
through the mind of an animal ; and again, the fact that writers
differ to a great extent in the meaning which they attribute to
the above terms, causes a further difficulty. If one may judge
from various articles which have been published lately, tho
greatest stress seems to be laid on the supposed entire absence
in animals of the power of abstraction, or of forming general
concepts. But when a dog sees another dog at a distance, it is
often clear that he perceives that it is a dog in the abstract ; for
when he gets nearer his whole manner suddenly changes, if the
other dog be a friend. A recent writer remarks, that in all sue li
cases it is a pure assumption to assert that the mental act is
not essentially of the same nature in the animal as in man. It'
either refers what he perceives with his senses to a mental
concept, then so do both.* 4 When I say to my terrier, in an
eager voice (and I have made the trial many times), "Hi, hi,
where is it ? " she at once takes it as a sign that something is to
be hunted, and generally first looks quickly all around, and
then rushes into the nearest thicket, to scent for any game, but
finding nothing, she looks up into any neighbouring tree for a
squirrel. Now do not these actions clearly shew that she had in
her mind a general idea or concept that some animal is to be
discovered and hunted ?
It may be freely admitted that no animal is self-conscious,
if by this term it is implied, that he reflects on such points, as
whence he comes or whither he will go, or what is life and death,
and so forth. But how can we feel sure that an old dog with an
excellent memory and some power of imagination, as shewn by
his dreams, never reflects on his past pleasures or pains in the
chase ? And this would be a form of self-consciousness. On the
other hand, as Biichner 45 has remarked, how little can the hard-
worked wife of a degraded Australian savage, who uses very
few abstract w< rds, and cannot count above four, exert her self-
consciousness, or reflect on the nature of her own existence. It
is generally admitted, that the higher animals possess memory,
44 Mr. Hookham, in a letter to 45 ' Conferences sur la Theorie
Pro£ Max Mtiller, in tbs * Birming- Darwinienne,' French translat.
bsm News,' May 1873, 186ft p. 132.
G 2
84 The Descent of Math Pabt L
attention, association, and even some imagination and reason.
If these powers, which differ much in different animals, are
capable of improvement, there seems no great improbability in
more complex faculties, such as the higher forms of abstraction,
and self-consciousness, &c, having been evolved through the
development and combination of the simpler ones. It has been
urged against the views here maintained, that it is impossible
to say at what point in the ascending scale animals become
capable of abstraction, &c. ; but who can say at what age this
occurs in our young children ? We see at least that such powers
ire developed in children by imperceptible degrees.
That animals retain their mental individuality is unquestion-
able. When my voice awakened a train of old associations in
the mind of the before-mentioned dog, he must have retained
his mental individuality, although every atom of his brain had
probably undergone change more than once during the interval
of five years. This dog might have brought forward the
argument lately advanced to crush all evolutionists, and said,
" I abide amid all mental moods and all material changes. . . .
" The teaching that atoms leave their impressions as legacies to
" other atoms falling into the places they have vacate! is con-
" tradictory of the utterance of consciousness, and is therefore
" false ; but it is the teaching necessitated by evolutionism, con-
" sequently the hypothesis is a false one." 46
Language. — This faculty has justly been considered as one of
the chief distinctions between man and the lower animals. But
man, as a highly competent judge, Archbishop Whately remarks,
" is not the only animal that can make use of language to express
" what is passing in his mind, and can understand, more or less,
"what i3 so expressed by another." 47 In Paraguay the Cebus
azarce when excited utters at least six distinct sounds, which
excite in other monkeys similar emotions. 48 The movements of
the features and gestures of monkeys are understood by us, and
tHy partly understand ours, as Bengger and others declare. It
h a more remarkable fact that the dog, since being domesticated,
has learnt to bark 49 in at least four or five distinct tones.
Although barking is a new art, no doubt the wild parent-species
of the dog expressed their feelings by cries of various kinds.
With the domesticated dog we have the bark of eagerness, as in
the chase ; that of anger, as well as growling ; the yelp or howl of
despair, as when shut up ; the baying at night ; the bark of joy, as
*« The Rev. Dr. J. M'Cann, * Anti- 4 » Rengger, ibid. s. 45.
Darwinism,' 1869, p. 13. 4B See my * Variation of Aid-
47 Quoted in 'Anthropological Re- mals and Plants under Domestic**
new ' 1884, p. 158. tion,' vol. i. p. 27,
3hai\ III. Mental Powers. 85
when starting on a walk with his mastor ; and the very distinct
one of demand or supplication, as when wishing for a door or
window to be opened. According to Houzeau, who paid par-
ticular attention to the subject, the domestic fowl utters at least
a dozen significant sounds. 50
The habitual use of articulate language is, however, peculiar
to man ; but he uses, in common with the lower animals, inarti-
culate cries to express his meaning, aided by gestures and the
movements of the muscles of the face. 51 This especially holds
good with the more simple and vivid feelings, which are but
little connected with our higher intelligence. Our cries of pain,
fear, surprise, anger, together with their appropriate actions,
and the murmur of a mother to her beloved child, are more
expressive than any words. That which distinguishes man
from the lower animals is not the understanding of articulate
sounds, for, as every one knows, dogs understand many words
and sentences. In this respect they are at the same stage of
development as infants, between the ages of ten and twelve
months, who understand many words and short sentences, but
cannot yet utter a single word. It is not the mere articulation
which is our distinguishing character, for parrots and other
birds possess this power. Nor is it the mere capacity of con-
necting definite sounds with definite ideas ; for it is certain that
some parrots, which have been taught to speak, connect un-
erringly words with things, and persons with events. 52 The
lower animals differ from man solely in his almost infinitely
larger power of associating together the most diversified
50 * Faculty Mentales des Ani- to add to the " good morning " a
maux,' torn. ii. 1872, p. 346-349. short sentence, which "was never
51 See a discussion on this subject once repeated after his , father's
in Mr. E. B. Tylor's very interesting death. He scolded violently a
work, * Researches into the Early strange dog which came into the
History of Mankind/ 1865, chaps, room through the open window;
ii. to iv. and he scolded another parrot (say-
82 I have received several detailed ing " you naughty polly ") which
accounts " to this effect. Admiral had got out of its cage, and was
Sir J. Sulivan, whom 1 know to be eating apples on the kitchen table,
a careful observer, assures me that See also, to the same effect, Houzeau
sin African parrot, long kept in his on parrots, * Facultes Mentales,'
father's house, invariably called torn. ii. p. 309. Dr. A. Moschkau
certain persons of the household, as informs me that he knew a starling
veil as visitors, by their names. He which never made a mistake in
said " good morning " to every one at saying in German " good morning "
breakfast, and " good night " to eacli to persons arriving, and " good-
as they left the room at night, and bye, old fellow," to those departing*
never reversed these salutations. 1 could add several other such
To Sir J. Sulivan's father, he used cases.
86 Tlie Descent of Man. I'abt I.
sounds and ideas; and this obviously depends on the high
development of his mental powers.
As Home Took, one of the founders of the noble science of
philology, observes, language is an art, like brewing or bald ng ;
but writing would have been a better simile. It certainly is not
a true instinct, for every language has to be learnt. It diffei%
however, widely from all ordinary arts, for man has an in-
stinctive tendency to speak, as we see in the babble of our
young children ; whilst no child has an instinctive tendency to
brew, bake, or write. Moreover, no philologist now supposes
that any language has been deliberately invented ; it has been
slowly and unconsciously developed by many steps. 33 The
sounds uttered by birds offer in several respects the nearest
analogy to language, for all the members of the same species utter
the same instinctive cries expressive of their emotions ; and all
the kinds which sing, exert their power instinctively ; but the
actual song, and even the call-notes, are learnt from their
parents or foster-parents. These sounds, as Daines Barrington 54
has proved, " are no more innate than language is in man."
The first attempts to sing " may be compared to the imperfect
" endeavour in a child to babble." The young males ' continue
practising, or as the bird-catchers say, " recording," for ten or
eleven months. Their first essays show hardly a rudiment of
the future song ; but as they grow older we can perceive what
they are aiming at ; and at last they are said " to sing their
" song round/' Nestlings which have learnt the song of a distinct
species, as with the canary-birds educated in the Tyrol, teach
and transmit their n&w song to their offspring. The slight
natural differences of song in the same species inhabiting
different districts may be appositely compared, as Barrington
remarks, " to provincial dialects ;" and the songs of allied,
though distinct species may be compared with the languages of
distinct races of man. I have given the foregoing details to
shew that an instinctive tendency to acquire an art is not
peculiar to man.
With respect to the origin of articulate language, aftor having
read on the one side the highly interesting works of Mr. Hens-
43 See some good remarks on this " gards the immediate end te be
head by Pro£ Whitney, in his "attained; unconsciously as regards
* Oriental and Linguistic Studies,' " the further consequences of the
1873, p. 354. He observes that the " id.**
desire of communication between * 4 Hon. Daines Barrington in
man is the living force, which, * Philosoph. Transactions,' 177o, p.
in the development of language, 262. See alsc Dureau de la Malle,
"works both consciously and un- iu 'Ann. des. Sc. Nat.' 3rd series,
"consciously consciously as re- Zoolog. torn. x. p. 119.
Chap. 111. Mental Powers. 8;
Ieigh Wedgwood, the Rev. F. Farrar, and Prof. Schleicher, 56 and
the celebrated lectures of Prof. Max Miiller on the other side, I
cannot doubt that language owes its origin to the imitation and
modification of yarious natural sounds, the voices of other
animals, and man's own instinctive cries, aided by signs and
gestures. When we treat of sexual selection we shall see that
primeval man, or rather some early progenitor of man, probably
first used his voice in producing true musical cadences, that is
in singing, as do some of the gibbon-apes at the present day;
and we may conclude from a widely-spread analogy, that this
power would have been especially exerted during the courtship
of the sexes, — would have expressed various emotions, such as
love, jealousy, triumph, — and would have served as a challenge to
rivals. It is, therefore, probable that the imitation of musical
cries by articulate sounds may have given rise to words expres-
sive of various complex emotions. The strong tendency in our
nearest allies, the monkeys, in microcephalous idiots, 66 and in
the barbarous races of mankind, to imitate whatever they hear
deserves notice, as bearing on the subject of imitation. Since
monkeys certainly understand much that is said to them by
man, and when wild, utter signal-cries of danger to their
fellows ; 67 and since fowls give distinct warnings for danger oe
the ground, or in the sky from hawks (both, as well as a third
cry, intelligible to dogs), 58 may not some unusually wise ape-like
animal have imitated the growl of a beast of prey, and thus
told his fellow-monkeys the nature of the expected danger ? This
would have been a first step in the formation of a language.
As the voice was used more and more, the vocal organs would
have been strengthened and perfected through the principle of
the inherited effects of use ; and this would have reacted on the
power of speech. But the relation between the continued use of
language and the development of the brain, has no doubt been
far more important. The mental powers in some early pro-
genitor of man must have been more highly developed than in
55 ' On the Origin of Language,' M Vogt, * Memoire sur les Micro-
by H. Wedgwood, 1866. 'Chapters cephales,' 1867, p. 169. With re-
on Language/ by the Rev. F. W. spect to savages, I have given some
Farrar, 1865. These works are facts in my ' Journal of Researches/
most interesting. See also * De la &c, 1845, p. 206.
Phys. et de Parole,' par Albert " See clear evidence on this head
Lemoine, 1865, p. 190. The work in the two works so often quoted,
on this subject, by the late Prof, by Brehm and Rengger.
Aug. Schleicher, has been translated 58 Houzeau gives a very curious
by Dr. Bikkers into English, under account of his observations on this
the title of ' Darwinism tested by subject in his i Facultes Mentales
the Science of Language,' 1869 des Animaux,' torn, ii., p. 348.
88 The Descent of Man. Pah* ;
any existing ape, before even the most imperfect form of speech
could have come into use ; but we may confidently believe that
the continued use and advancement of this power would have
reacted on the mind itself, by enabling and encouraging it to
carry on long trains of thought. A complex train of thought
can no more be carried on without the aid of words, whether
spoken or silent, than a long calculation without the use of
figures or algebra. It appears, also, that even an ordinary train
of thought almost requires, or is greatly facilitated by some
form of language, for the dumb, deaf, and blind girl, Laura
Bridgman, was observed to use her fingers whilst dreaming. 5 *
Nevertheless, a long succession of vivid and connected ideas may
pass through the mind without the aid of any form of language,
as we may infer from the movements of dogs during their
dreams. We have, also, seen that animals are able to x*eason
to a certain extent, manifestly without the aid of language.
The intimate connection between the brain, as it is now
developed in us, and the faculty of speech, is well shewn by
those curious cases of brain-disease in which speech is specially
affected, as when the power to remember substantives is lost,
whilst other words can be correctly used, or where substantives
of a certain class, or all except the initial letters of substantives
and proper names are forgotten, 60 There is no more improb-
ability in the continued use of the mental and vocal organs
leading to inherited changes in their structure and functions,
than in the case of handwriting, which depends partly on the
form of the hand and partly on the disposition of the mind ; and
hand- writing is certainly inherited. 61
Several writers, more especially Prof. Max Miiller, 62 have
lately insisted that the use of language implies the power of
forming general concepts ; and that as no animals are supposed
to possess this power, an impossible barrier is formed between
them and man. 63 With respect to animals, I have already
6 * See remarks on this head by 62 Lectures on 'Mr. Darwin's Phi-
Dr. Maudsley, 'The Physiology and losophy of Language,* 1873.
Pathology of Miod,* 2nd edit. 1868, 63 The judgment of a distin-
p. 199. guished philologist, such as Prof.
6a Many curious cases have been Whitney, will have far more weight
recorded. See, for instance, Dr. on this point than anything that
Sateman * On Aphasia,' 1870, p. 27, I can say. He remarks (* Oriental
31, 53, 100, &c. Also, * Inquiries and Linguistic Studies,' 1873, p
Concerning the Intellectual Powers, 297), in speaking of Bleek's views .
by Dr. Abercrombie, 1838, p. 150. '* Because on the grand scale lan-
61 'The Variation of Animals " guage is the necessary auxiliary
and Plants under Domestication,' " of thought, indispensable to the
vol. ii. p. 6. " development of the power of
Chap. III. Mental Powers. 89
endeavoured to show that they have this power, at least in a
rude and incipient degree. As far as concerns infants of from
ten to eleven months old, and deaf-mutes, it seems to me in-
credible, that they should be able to connect certain sounds with
certain general ideas as quickly as they do, unless such ideas
were already formed in their minds. The same remark may be
extended to the more intelligent animals ; as Mr. Leslie Stephen
observes, 64 " A dog frames a general concept of cats or sheep,
" and knows the corresponding words as well as a philosopher.
" And the capacity to understand is as good a proof of vocal
" intelligence, though in an inferior degree, as the capacity to
Why the organs now used for speech should have been
originally perfected for this purpose, rather than any other
organs, it is not difficult to see. Ants have considerable powers
of intercommunication by means of their antennae, as shewn by
Huber, who devotes a whole chapter to their language. We
might have used our fingers as efficient instruments, for a
person with practice can report to a deaf man every word of a
speech rapidly delivered at a public meeting; but the loss of
our hands, whilst thus employed, would have been a serious
inconvenience. As all the higher mammals possess vocal organs,
constructed on the same general plan as ours, and used as a
means of communication, it was obviously probable that these
same organs would be still further developed if the power of
communication had to be improved ; and this has been effected by
the aid of adjoining and well adapted parts, namely the tongue
and lips. 65 The fact of the higher apes not using their vocal
organs for speech, no doubt depends on their intelligence not
having been sufficiently advanced. The possession by them of
" thinking, to the distinctness and " fingers into imitation of spoken
" variety and complexity of cogni- " words." Max Miiller gives in
" tions to the fall mastery of con- italics (' Lectures on Mr. Darwin's
"sciousness; therefore he would Philosophy of Language,' 1873,
*' fain make thought absolutely im- third lecture) the following aphor-
u possible without speech, identify- ism : " There is no thought with-
" ing the faculty with its instru- " out words, as little as there are
" rnent. He might just as reason- " words without thought." What
" ably assert that the human hand a strange definition must here be
*' cannot act without a tool. With given to the word thcught !
" such a doctrine to start from, he 6 * * Essays on Free-thinking,' &c,
" cannot stop short of Miiller's 1873. p. 82.
" worst paradoxes, that an infant tt5 See some good remarks to this
" (in fans, not speaking) is not a effect by Dr. Maudsley, ' The Phy-
** human being, and that deaf-mutes biology and Pathology of Mind,
'•' do not become posssssed of reason 1868, p. 199.
u until they learn ;o twist their
90 TJie Descent of Man. f aet i<
organs, which with long-continued practice might have been
used for speech, although not thus used, is paralleled by the
case of many birds which possess organs fitted for singing,
though they never sing. Thus, the nightingale and crow have
vocal organs similarly constructed, these being used by the
former for diversified song, and by the latter only for croaking. 66
If it be asked why apes have not had their intellects developed
to the same degree as that of man, general causes only can be
Assigned in answer, and it is unreasonable to expect anything
more definite, considering our ignorance with respect to the
successive stages of development through which each creature
has passed.
The formation of different languages and of distinct species,
and the proofs that both have been developed through a gradual
process, are curiously parallel. 67 But we can trace the formation
of many words further back than that of species, for we can
perceive how they actually arose from the imitation of various
sounds. We find in distinct languages striking homologies due
to community of descent, and analogies due to a similar process
of formation. The manner in which certain letters or sounds
change when others change is very like correlated growth. We
have in both cases the reduplication of parts, the effects of long-
continued use, and so forth. The frequent presence of rudi-
ments, both in languages and in species, is still more remarkable.
The letter m in the word am, means 1 ; so that in the expres-
sion / am, a superfluous and useless rudiment has been retained.
In the spelling also of words, letters often remain as the rudi-
ments of ancient forms of pronunciation. Languages, like
organic beings, can be classed in groups under groups : and they
can be classed either naturally according to descent, or arti-
ficially by other characters. Dominant languages and dialects
spread widely, and lead to the gradual extinction of other
tongues. A language, like a species, when once extinct, never,
as Sir C. Lyell remarks, reappears. The same language never
has two birth-places. Distinct languages may be crossed or
blended together. 68 We see variability in every tongue, and new
68 Macgillivray, * Hist, of British display any unusual capacity for
Birds/ vol. ii. 1839, p. 29. An imitation. ' Researches in Zoology,
excellent observer, Mr. Blackwall, 1834, p. 158.
remarks that the magpie learns to 67 See the very interesting pa-
pronounce single words, and even rallelism between the development
short sentences, more readily than of species and languages, given by
almost any other British bird ; yet, Sir C. Lyell in * The Geolog. Evi-
as he adds, after long ana ciosely dences of the Antiquity of Man,'
investigating its habits, he has 1863, chap, xxiii.
never knowi? it, in a state of nature, 68 See remarks to this effect by
Chap. III. Mental Powers. 91
words are continually cropping up ; but as there is a limit to
the powers of the memory, single words, like whole languages,
gradually become extinct. As Max Muller 69 has well re-
marked : — " A struggle for life is constantly going on amongst
"the words and grammatical forms in each language. The
" better, the shorter, the easier forms are constantly gaining the
" upper hand, and they owe their success to their own inherent
" virtue." To these more important causes of the survival of
certain words, mere novelty and fashion may be added; for
there is in the mind of man a strong love for slight changes in all
things. The survival or preservation of certain favoured words
in the struggle for existence is natural selection.
The perfectly regular and wonderfully complex construction
of the languages of many barbarous nations has often been
advanced as a proof, either of the divine origin of these lan-
guages, or of the high art and former civilisation of their
founders. Thus F. von Schlegel writes: "In those languages
" which appear to be at the lowest grade of intellectual culture,
" we frequently observe a very high and elaborate degree of art
"in their grammatical structure. This is especially the case
" with the Basque and the Lapponian, and many of the Ame-
" rican languages." 70 But it is assuredly an error to speak of
any language as an art, in the sense of its having been elabor-
ately and methodically formed. Philologists now admit that
conjugations, declensions, &c, originally existed as distinct
words, since joined together; and as such words express the
most obvious relations between objects and persons, it is not
surprising that they should have been used by the men of most
races during the earliest ages. With respect to perfection, the
following illustration will best shew how easily we may err : a
Crinoid sometimes consists of no less than 150,000 pieces of
shell, 71 all arranged with perfect symmetry in radiating lines ;
but a naturalist does not consider an animal of this kind as
more perfect than a bilateral one with comparatively few parts,
and with none of these parts alike, excepting on the opposite sides
of the body. He justly considers the differentiation and special-
isation of organs as the test of perfection. So with languages •
the most symmetrical and complex ought not to be ranked above
irregular, abbreviated, and bastardised languages, which have
the Rev. F. W. Farrar, in an in- 7<> Quoted by C. S. Wake, « Chap-
teresting article, entitled ' Philo- ters on Man,' 1868, p. 101.
logy and Darwinism' in * Nature/ 71 Buckland, ' Bridgewater Trea-
March 24th, 1870, p. 528. tise/ p. 411.
«» 'Nature/ Jan. 6th, 187C p. 257.
92 The Descent of Man. pAKr L
borrowed expressive words and useful forms of construction from
various conquering, conquered, or immigrant races.
From these few and imperfect remarks I conclude that the
extremely complex and regular construction of many barbarous
languages, is no proof that they owe their origin to a special
act of creation. 72 Nor, as we have seen, does the faculty of
articulate speech in itself offer any insuperable objection to
the belief that man has been developed from some lower
form.
Sense of Beauty. — This sense has been declared to be peculiar
to man. I refer here only to the pleasure given by certain
colours, forms, and sounds, and which may fairly be called a
sense of the beautiful ; with cultivated men such sensations are.,
however, intimately associated with complex ideas and trains of
thought. When we behold a male bird elaborately displaying
his graceful plumes or splendid colours before the female,
whilst other birds, not thus decorated, make no such display,
it is impossible to doubt that she admires the beauty of her
male partner. As women everywhere deck themselves with
these plumes, the beauty of such ornaments cannot be disputed.
As we shall see later, the nests of humming-birds, and the
playing passages of bower-birds are tastefully ornamented
with gaily-coloured objects; and this shews that they must
receive some kind of pleasure from the sight of such things.
With the great majority of animals, however, the taste for the
beautiful is confined, as far as we can judge, to the attractions
of the opposite sex. The sweet strains poured forth by many
male birds during the season of love, are certainly admired by
the females, of which fact evidence will hereafter be given. If
female birds had been incapable of appreciating the beautiful
colours, the ornaments, and voices of their male partners, all the
labour and anxiety exhibited by the latter in displaying their
charms before the females would have been thrown away ; and
this it is impossible to admit. Why certain bright colours
should excite pleasure cannot, I presume, be explained, any
more than why certain flavours and scents are agreeable ; but
habit has something to do with the result, for that which is at
first unpleasant to our senses, ultimately becomes pleasant, and
habits are inherited. With respect to sounds, Helmholtz has
explained to a certain extent on physiological principles, why
harmonies and certain cadenees are agreeable. But besides
this, sounds frequently recurring at irregular intervals are
72 See some good remarks on the J. Lubbock, * Origin of C.vilisaiicKOj
simplification of languages, by Sir 1870, p. 273.
Chap. III. Menial Powers. 93
highly disagreeable, as every one will admit who has listened at
night to the irregular flapping of a rope on board ship. The
same principle seems to come into play with vision, as the
eye prefers symmetry or figures with some regular recurrence.
Patterns of this kind are employed by even the lowest savages
as ornaments; and they have been developed through sexual
selection for the adornment of some male animals. Whether we
can or not give any reason for the pleasure thus derived from
vision and hearing, yet man and many of the lower animals are
alike pleased by the same colours, graceful shading and forms,
and the same sounds.
The taste for the beautiful, at least as far as female beauty is
concerned, is not of a special nature in the human mind; for it
differs widely in the different races of man, and is not quite the
same even in the different nations of the same race. Judging
from the hideous ornaments, and the equally hideous music
admired by most savages, it might be urged that their aesthetic
faculty was not so highly developed as in certain animals, for
instance, as in birds. Obviously no animal would be capable of
admiring such scenes as the heavens at night, a beautiful land-
scape, or refined music; but such high tastes are acquired
through culture, and depend on complex associations ; they are
not enjoyed by barbarians or by uneducated persons.
Many of the faculties, which have been of inestimable service
to man for his progressive advancement, such as the powers of
the imagination, wonder, curiosity, an undefined sense of beauty,
a tendency to imitation, and the love of excitement or novelty,
could hardly fail to lead to capricious changes of customs and
fashions. I have alluded to this point, because a recent writer 73
has oddly fixed on Caprice " as one of the most remarkable and
"typical differences between savages and brutes." But not
only can we partially understand how it is that man is from
various conflicting influences rendered capricious, but that
the lower animals are, as we shall hereafter see, likewise capri-
cious in their affections, aversions, and sense of beauty. There
is also reason to suspect that they love novelty, for it own sake.
Belief in God — Religion. — There is no evidence that man was
aboriginally endowed with the ennobling belief in the existence
of an Omnipotent God. On the contrary there is ample evidence,
derived not from hasty travellers, but from men who have lccg
resided with savages, that numerous races have existed, and still
exist, who have no idea of one or more gods, and who have no
« <The Spectator/ Dec. 4th, 1869, p. 1130.
94 The Descent of Man. Pabt I,
words in their languages to express such an idea. 74 The question
is of course wholly distinct from that higher one, whether there
exists a Creator and Euler of the universe ; and this has Ken
answered in the affirmative by some of the highest intellects that
, have ever existed.
If, however, we include under the term " religion " the belief
I in unseen or spiritual agencies, the case is wholly different ; for
1 this belief seems to be universal with the less civilised races.
Nor is it difficult to comprehend how it arose. As soon as the
important faculties of the imagination, wonder, and curiosity,
together with some power of reasoning, had become partially
developed, man would naturally crave to understand what was
passing around him, and would have vaguely speculated on his
own existence. As Mr. M'Lennan 75 has remarked, " Some explan-
" ation of the phenomena of life, a man must feign for himself-
" and to judge from the universality of it, the simplest hypothesis ,
" and the first to occur to men, seems to have been that natural
" phenomena are ascribable to the presence in animals, plants,
" and things, and in the forces of nature, of such spirits prompting
" to action as men are conscious they themselves possess." It
is also probable, as Mr. Tylor has shewn, that dreams may have
first given rise to the notion of spirits ; for savages do not readily
distinguish between subjective and objective impressions. When
a savage dreams, the figures which appear before him are
believed to have come from a distance, and to stand over him ;
or " the soul of the dreamer goes out on its travels, and comes
" home with a remembrance of what it has seen." 76 But until
74 See an excellent article on this forms of religious belief throughout
subject by the Rev. F. W. Farrar, the world, by man being led through
in the i Anthropological Review/ dreams, shadows, and other causes,
Aug. 1864, p. cexvii. For further to look at himself as a double
facts see Sir J. Lubbock, ' Pre- essence, corporeal and spiritual. As
historic Times,' 2nd edit. 1869, p. the spiritual being is supposed to
564 ; and especially the chapters on exist after death and to be power-
Religion in his * Origin of Oivilisa- ful, it is propitiated by various gifts
tion/ 1870. and ceremonies, and its aid invoked.
75 ' The Worship of Animals and He then further shews that names
Plants/ in the * Fortnightly Review,' or nicknames given from some
Oct. 1, 1869, p. 422. animal or other object, to the eariy
79 Tylor, * Early History of Man- progenitors or founders of a tribe,
kind/ 1865, p. 6. See also the are supposed after a long intervnl
three striking chapters on the De- to represent the real progenitor of
velopment of Religion, in Lubbock's the tribe ; and such animal or object
' Origin of Civilisation/ 1870. In a is then naturally believed still to
like manner Mr. Herbert Spencer, exist as a spirit, is held sacred, and
in his ingenious essay in the ' Fort- worshipped as a god. Nevertheless
nightly Review' (May 1st, 1870, I cannot but suspect that there is
p. 535), accounts for the earliest a still earlier and ruder stage, whea
Chap. HI. Mental Powers. 95
the faculties of imagination, curiosity, reason, &c, had been
fairly well developed in the mind of man, his dreams would not
have led him to believe in spirits, any more than in the case of
& dog.
The tendency in savages to imagine that natural objects and
agencies are animated by spiritual or living essences, is perhaps
illustrated by a little fact which I once noticed : my dog, a full-
grown and very sensible animal, was lying on the lawn during a
hot and still day ; but at a little distance a slight breeze occa-
sionally moved an open parasol, which would have been wholly
disregarded by the dog, had any one stood near it. As it was,
every time that the parasol slightly moved, the dog growled
fiercely and barked. He must, I think, have reasoned to himself
in a rapid and unconscious manner, that movement without any
apparent cause indicated the presence of some strange living
agent, and that no stranger had a right to be on his territory.
The belief in spiritual agencies would easily pass into the
belief in the existence of one or more gods. For savages would
naturally attribute to spirits the same passions, the same love of
vengeance or simplest form of justice, and the same affections
which they themselves feel. The Fuegians appear to be in this
respect in an intermediate condition, for when the surgeon on board
the "Beagle" shot some young ducklings as specimens, York
Minster declared in the most solemn manner, " Oh, Mr. Bynoe,
" much rain, much snow, blow much ;" and this was evidently
a retributive punishment for wasting human food. So again he
related how, when his brother killed a " wild man," storms long
raged, much rain and snow fell. Yet we could never discover
that the Fuegians believed in what we should call a God, or
practised any religious rites ; and Jemmy Button, with justifiable
pride, stoutly maintained that there was no devil in his land.
This latter assertion is the more remarkable, as with savages the
belief in bad spirits is far more common than that in good
t>nes.
The feeling of religious devotion is a highly complex one,
consisting of love, complete submission to an exalted and
mysterious superior, a strong sense of dependence, 77 fear,
reverence, gratitude, hope for the future, and perhaps other
elements. No being could experience so complex an emotion
anything which manifests power or " See an able article on the
movement is thought to be endowed ' Physical Elements of Religion/ by
with some form of life, and with Mr. L. Owen Pike, in * Anthropolet;,
mental faculties analcgtr.is to our &»▼&»,' April, 1870, p. lxiii.
own.
q6 The Descent of Man. Part 1
until advanced in his intellectual and moral faculties to at least
a moderately nigh level. Nevertheless, we see some distant
approach to this state of mind in the d:ep love of a dog for his
master, associated with complete submission, some fear, and
perhaps other feelings. The behaviour of a dog when returning
to his master after an absence, and, as I may add, of a monkey
to his beloved keeper, is widely different from that towards their
fellows. In the latter case the transports of joy appear to be
somewhat less, and the sense of equality is shewn in every action.
Professor Braubach goes so far as to maintain that a dog looks
on his master as on a god. 78
The same high mental faculties which first led man to believe
in unseen spiritual agencies, then in fetishism, polytheism, and
ultimately in monotheism, would infallibly lead him, as long as
his reasoning powers remained poorly developed, to various
strange superstitions and customs. Many of these are terrible
to think of — such as the sacrifice of human beings to a blood-
loving god ; the trial of innocent persons by the ordeal of poison
or fire ; witchcraft, &c. — yet it is well occasionally to reflect on
these superstitions, for they shew us what an infinite debt of
gratitude we owe to the improvement of our reason, to science,
and to our accumulated knowledge. As Sir J. Lubbock 79 has well
observed, " it is not too much to say that the horrible dread of
" unknown evil hangs like a thick cloud over savage life, and
" embitters every pleasure." These miserable and indirect
consequences of our highest faculties may be compared with the
incidental and occasional mistakes of the instincts of the lower
animals.
78 ' Religion, Moral, &c, der Dar- T9 ' Prehistoric Times,* 2nd edit,
win'schen Art-Lehre,' 1869, s. 53. p. 571. In this work (p. 571)
It is said (Dr. W, Lauder Lindsay, there will be found an excellent
4 Jcurnal of Mental Science,* 1871, account of the many strange and
p. 43), that Bacon long ago, and the capricious customs of savages,
poe ; Burns, held the same notion.
Ob at. \> Moral Setise. 97
CHAPTEE IV.
COMrARISOS OF THE MENTAL POWERS OP MAN AND THE
Lower Animals — continued.
The moral sense — Fundamental proposition — The qualities of social
animals — Origin of sociability— Struggle between opposed instincts —
Man a social animal — The more enduring social instincts conquer other
less persistent instincts — The social virtues alone regarded by savages —
The self-regarding virtues acquired at a later stage of development —
The importance of the judgment of the members of the same community
on conduct — Transmission of moral tendencies — Summary.
I fully subscribe to the judgment of those writers 1 who
maintain that of all the differences between man and the
lower animals, the moral sense or conscience is by far the
most important. This sense, as Mackintosh 2 remarks, " has a\
" rightful supremacy over every other principle of human
"action;" it is summed up in that short but imperious word
ougJit, so full of high significance. It is the most noble of all
the attributes of man, leading him without a moment's hesita-
tion to risk his life for that of a fellow-creature ; or after due
deliberation, impelled simply by the deep feeling of right or
duty, to sacrifice it in some great cause. Immanuel Kant
exclaims, " Duty ! Wondrous thought, that workest neither by
" fond insinuation, flattery, nor by any threat, but merely by
"holding up thy naked law in the soul, and so extorting for
"thyself always reverence, if not always obedience; before
" whom all appetites are dumb, however secretly they rebel ;
" whence thy original ?" 8
This great question has been discussed by many writers 4 of
consummate ability ; and my sole excuse for touching on it, is
the impossibility of here passing it over ; and because, as far as I
know, no one has approached it exclusively from the side of
natural history. The investigation possesses, also, some in-
1 See, for instance, on this subject, and Moral Science,' 1868, p. 543-
Quatrefages, * Unite' de PEspece 725) of twenty-six British authors
Humaine,' 1861, p. 21, &c. who have written on this subject,
2 * Dissertation on Ethical Philo- and whose names are familiar to
sophy,' 1837, p. 231, &c. every reader ; to these, Mr. Bain's
s 4 Metaphysics of Ethics,' trans- own name, and those of Mr. Lecky,
lated by J. W. Semple, Edinburgh, Mr. Shadworth Hodgson, Sir J.
;836, p. 136. Lubbock, and others, might be
* Mr. Bah gives a list (' Mental added.
98 The Descent of Man. Part I
dopendont interest, as an attempt to see how far the study of
the lower animals throws light on one of the highest psychical
faculties of man.
The following proposition seems to me in a high degree
probable — namely, that any animal whatever, endowed with
well-marked social instincts, 6 the parental and filial affections
being here included, would inevitably acquire a moral sense or
conscience, as soon as its intellectual powers had become as well,
\ or nearly as well developed, as in man. For, firstly, the social
instincts lead an animal to take pleasure in the society of its
fellows, to feel a certain amount of sympathy with them, and to
perform various services for them. The services may be of a
definite and evidently instinctive nature ; or there may be only
a wish and readiness, as with most of the higher social animals,,
to aid .their, fellows in certain general ways. But these feelings
and services are by no means extended to all the individuals of
the same species, only to those of the same association. Secondly ,
as soon as the mental faculties had become highly developed,
images of all past actions and motives would be incessantly
passing through the brain of each individual ; and that feeling
of dissatisfaction, or even misery, which invariably results, as we
shall hereafter see, from any unsatisfied instinct, would arise,
as often as it was perceived that the enduring and always
present social instinct had yielded to some other instinct, at the
time stronger, but neither enduring in its nature, nor leaving
5 Sir B. Brodie, aftei observing all this, he also remarks, " if, as is
that man is a social animal (' Psy- " my own belief, the moral feelings
chological Enquiries/ 1854, p. 192), " are not innate, but acquired, they
asks the pregnant question, " ought " are not for that reason less natu-
" not this to settle the disputed " ral." It is with hesitation that I
" question as to the existence of a venture to differ at all from so
" moral sense ?" Similar ideas have profound a thinker, but it can
probably occurred to many persons, hardly be disputed that the social
as they did long ago to Marcus feelings are instinctive or innate in
Aurelius. Mr. J. S. Mill speaks, in the lower animals ; and why should
his celebrated work, * Utilitarian- they not be so in man ? Mr. Bain
ism,' (1864, pp. 45, 46), of the social (see, for instance, 'The Emotions and
feelings as a "powerful natural the Will,' 1865, p. 481) and others
" sentiment," and as " the natural believe that the moral sense is ac-
" basis of sentiment for utilitarian quired by each individual during
" morality." Again he says, " Like his lifetime. On the general theory
" the other acquired capacities above of evolution this is at least ex-
" referred to, the moral faculty, if tremely improbable. The ignoring
" not a part of our nature, is of all transmitted mental qualities
*' a natural out-growth from it ; will, as it seems to me, bo hereafter
* 4 capable, like them, in a certain judged as a most serious blemish ia
*' small degree of springing up spon- the works of Mr. Mill.
'* taiieonsly." But in opposition to
Chap. IV. Moral Sense, 9g
behind it a very vivid impression. It is clear that many in-
stinctive desires, such as that of hunger, are in their nature of
short duration; and after being satisfied, are not readily or
vividly recalled. Thirdly , after the power of language had been
acquired, and the wishes of the community could be expressed,
I the common opinion how each member ought to act for the
| public good, would naturally become in a paramount degree
Ithe guide to action. But it should be borne in mind that how-
ever great weight we may attribute to public opinion, our regard
for the approbation and disapprobation of our fellows depends ' \
on sympathy, which, as we shall see, forms an essential part of
the social instinct, and is indeed its foundation-stone, Lastly, \
habit in the individual would ultimately play a very important \
part in guiding the conduct of each member; for the social in- \
stinct, together with sympathy, is, like any other instinct, greatly
strengthened by habit, and so consequently would be obedience
to the wishes and judgment of the community. These several
subordinate propositions must now be discussed, and some of
them at considerable length.
f It may be well first to premise that I do not wish to maintain
that any strictly social animal, if its intellectual faculties were
to become as active and as highly developed as in man, would
acquire exactly the same moral sense as ours. In the same
manner as various animals have some sense of beauty, though
they admire widely different objects, so they might have a sense
of right and wrong, though led by it to follow widely different
lines of conduct. If, for instance, to take an extreme case, men
were reared under precisely the same conditions as hive-bees,
there can hardly be a doubt that our unmarried females would,
like the worker-bees, think it a sacred duty to kill their brothers,
and mothers would strive to kill their fertile daughters ; and no
4 one would think of interfering. 6 Nevertheless, the bee, or any
6 Mr. H. Sidgwick remarks, in in Morals,* 'Theological Review,
an able discussion on this subject April, 1872, p. 188-191) on the
(the * Academy/ June 15th, 1872, same illustration, says, the prin-
(p. 231), "a superior bee, we may ciples of social duty would be thus
" feel sure, would aspire to a milder reversed ; and by this, I presume,
" solution of the population ques- she means that the fulfilment of a
" tion." Judging, however, from social duty would tend to the injury
the habits of many or most savages, of individuals ; but she overlooks
man solves the problem by female the fact, which she would doubtless
infanticide, polyandry and promis- admit, that the instincts of the bee
cuous intercourse ; therefore it may have been acquired for the good of
well be doubted whether it would the community. She goes so far as
be by a milder method. Miss to say that if the theory of ethics
Cobbf, in commenting (* Darwinism advocated hi this chapter were ever
• H 2
loo TJie Descent of Man. Tart I.
other social animal, would gain in our supposed case, as i«t
appears to me, some feeling of right or wrong, or a conscience.
For each individual would have an inward sense of possessing
certain stronger or more enduring instincts, and others less
strong or enduring ; so that there would often be a struggle as to
which impulse should be followed; and satisfaction, dissatis-
faction, or even misery would be felt, as past impressions were
compared during their incessant passage through the mind. In
this case an inward monitor would tell the animal that it would
have been better to have followed the one impulse rather than
the other. The one course ought to have been followed, and the
other ought not ; the one would have been right and the other
wrong ; but to these terms I shall recur.
Sociability. — Animals of many kinds are social ; we find even
distinct species living together ; for example, some American
monkeys ; and united flocks of rooks, jackdaws, and starlings
Man shews the same feeling in his strong love for the dog, which
the dog returns with interest. Every one must have noticed ho*
miserable horses, dogs, sheep, &c, are when separated from
their companions, and what strong mutual affection the two
former kinds, at least, shew on their reunion. It is curious to
speculate on the feelings of a dog, who will rest peacefully for
hours in a room with his master or any of the family, without
the least notice being taken of him ; but if left for a short time
by himself, barks or howls dismally. "We will confine our
attention to the higher social animals ; and pass over insects,
although some of these are social, and aid one another in man;?
important ways. T^,m£sJL-£Oinitto^^
hig her animals is to warn one jgiothev of dn.ng p r by mp a^ <$}/
t heunit ed^nses^oTalir Every sportsman knows, as Dr. Jaeger
remarks, 7 how difficult it is to approach animals in a herd or
troop. Wild horses and cattle do not, I believe, make anj
danger-sign ah but the attitude of any one of them who first
discovers an enemy, warns the others. Babbits stamp Joudly on
the ground with their hind-feet as a signal : sheep and ohamois
do the same with their forefeet, uttering likewise a whistle.
M any birds r and some mammals, po st sentinels^wJiicJlJr. Jhe(j)
a^geof jfeals are said 8 generally to be _the_females. The leader
generally accepted, " I cannot but earth is not held by many persons
'* believe that in the hour of their on so weak a tenure.
" triumph would be sounded the 7 * Die Darwin'sche Theorie," s
44 knell of the virtue of mankind!" 101.
5t is to h« hoped that the belief in 8 Mr. R. Brown in * Proc. Zooiog,
the permanence of virtue on this Soc,' 1868, p. 409.
Chap. IV. Moral Sense. 101
of a troop of monkeys acts as the sentinel, and utters cries
expressive both of danger and of safety. 9 So cial animals perform
m any little services for each o ther : horses nibble,and cows lick
each other, on any spot which itches: monkeys search each
other for external parasites ; and Brehm states that after a troop <£>
of the Cercopitkecus griseo-viridls has rushed through a thorny
brake, each monkey stretches itself on a branch, and another
monkey sitting by, " conscientiously " examines its fur, and
extracts every thorn or burr.
A nimals also re nder morejimjgorta^^ :
thu s woTvelT an d some _other~T)easts of prjff hjratjin jpacksjand q^
aid "one anoth er "IrT attacking their victims. Pelicans fish ir;
concert. The Hamacfryas baboons turn over stones to find
insects, &c. ; and when they come to a large one, as many as can
stand round, turn it over together and share the booty. Social ~^
a nimals mutually defend eachj riher. Bull bisons in N. America* vP
when there is danger, drive the cows and calves into the middle
of the herd, whilst they defend the outside. I shall also in a
future chapter give an account of two young wild bulls at
Chillingham attacking an old one in concert, and of two stallions
together trying to drive away a third stallion from a troop of
mares. In Abyssinia, Brehm encountered a great troop of
baboons, who were crossing a valley : some had already ascended
the opposite mountain, and some were still in the valley : the
latter were attacked by the dogs, but the old males immediately
hurried down from the rocks, and with mouths widely opened,
roared so fearfully, that the dogs quickly drew back. They
were again encouraged to the attack ; but by this time all the 1
baboons had reascended the heights, excepting a young one,
about six months old, who, loudly calling for aid, climbed on a
block of rock, and wai surrounded. Now one of the largest f
males, a true hero, came down again from the mountain, slowly
went to the young one, coaxed him, and triumphantly led him '
away — the dogs being too much astonished to make an attack. /
I cannot resist giving another scene which was witnessed by this
same naturalist ; an eagle seized a young Cercopithecus, which,
by clinging to a branch, was not at once carried off; it cried /
loudly for assistance, upon which the other members of the troop,
with much uproar, rushed to the rescue, surrounded the eagle,
9 Bvehm, ' Thierleben,' B. i. 1864, the evidence of Alvarez, whose ob-
s. 52, 79. For the case of the serrations Brehm thinks quite trust-
monkeys extracting thorns from worthy. For the cases of the old
each other, see s. 54. With respect male baboons attacking tne dogs,
to the Hamadryas turning over see s. 79; and with respect to thf
stones, tfe fact is given (s. 76) on <agle, s. 50.
102 The Descent of Man. Paht 1
and pulled out so many feathers, that he no longer thought
of his prey, but only how to escape. This eagle, as Brehm
re marks, a ssur edly would never a gai n ai^a^ Ta single monk ey of
aLtroop. 10
It is certain that associated animals have a feeling of love for
each other, which is not felt by non-social adult animals. How
far in most cases they actually sympathise in the pains and
pleasures of others, is more doubtful, especially with respect to
pleasures. Mr. Buxton, however, who had excellent means of
observation, 11 states that his macaws, which lived free in Norfolk,
took " an extravagant interest " in a pair with a nest ; and when-
ever the female left it, she was surrounded by a troop " scream-
" ing horrible acclamations in her honour." It is often difficult
to judge whether animals have any feeling for the sufferings of
others of their kind. Who can say what cows feel, when they
surround and stare intently on a dying or dead companion ; ap-
parently, however, as Houzeau remarks, they feel no pity. That
animals sometimes are far from feeling any sympathy is too
certain; for they will expel a wounded animal from the herd, or
gore or worry it to death. This is almost the blackest fact in
natural history, unless, indeed, the explanation which has been
suggested is true, that their instinct or reason leads them to
expel an injured companion, lest beasts of prey, including man,
should be tempted to follow the troop. In this case their con-
duct is not much worse than that of the North American Indians,
who leave their feeble comrades to perish on the plains ; or the
Fijians, who, when their parents get old, or fall ill, bury them
alive. 12
Many animals, however, certainly sympathise with each other's
distress or danger. This is the case even with birds. Capt.
Stansbury 13 found on a salt lake in Utah an old and completely
blind pelican, which was very fat, and must have been well fed
for a long time by his companions. Mr. Blyth, as he informs
10 Mr. Belt gives the case of a n 'Annals and Mag. of Nat. Hist./
spider-monkey (Ateles) in Nicara- November, 1868, p. 382.
gua, which was heard screaming for 12 Sir J. Lubbock, * Prehistoric
nearly two hours in the forest, and Times/ 2nd edit. p. 446.
was found with an eagle perched 13 As quoted by Mr. L. H. Morgan
close by it. The bird apparsntly * The American Beaver/ 1868, p.
feared to attack as long as it re- 272. Capt. Stansbury also gives an
mained face to face ; and Mr. Belt interesting account of the manner
oeiieves, from what he has seen of in which a very young pelican,
the habits of these monkeys, that carried away by a strong stream,
they protect themselves from tagles was guided and encouraged in its
by keeping two or three together, attempts to reach the shore by halt
4 The Naturalist in Nicaragua/ 1874, a dozen old birds
p. lib.
Chai*. IV. Moral Sense, id*
me, saw Indian crows feeding two or three of their companions
which were blind ; and I have heard of an analogous case with
the domestic cock. We may, if we choose, call these actions
instinctive ; but such cases are much too rare for the develop-
ment of any special instinct. 14 I have myself seen a dog, who .
never passed a cat who lay sick in a basket, and was a great
friend of his, without giving her a few licks with his tongue, the
jsurest sign of kind feeling in a dog.
^Tt must be called sympathy that leads a courageous dog to
fly at any one who strikes his master, as he certainly will. I
saw a person pretending to beat a lady, who had a very timid
little dog on her lap, and the trial had never been made before ,
the little creature instantly jumped away, but after the pretended
beating was over, it was really pathetic to see how perseveringly
he tried to lick his mistress's face, and comfort her. Brehm 1S
states that when a baboon in confinement was pursued to be
punished, the others tried to protect him. It must have been
sympathy in the cases above given which led the baboons and
Cercopitheci to defend their young comrades from the dogs and
the eagle. I will give only one other instance of sympathetic
and heroic conduct, in the case of a little American monkey.
Several years ago a keeper at the Zoological Gardens shewed me
some deep and scarcely healed wounds on the nape of his own neck,
inflicted on him, whilst kneeling on the floor, by a fierce baboon.
The little American monkey, who was a warm friend of this
keeper, lived in the same large compartment, and was dreadfully
afraid of the great baboon. Nevertheless, as soon as he saw his
friend in peril, he rushed to the rescue, and by screams and bites
so distracted the baboon that the man was able to escape, after,
as the surgeon thought, running great risk of his life.
Besides love and sympathy, animals exhibit other qualities
connected with the social instincts, which in us would be called
moral ; and I agree with Agassiz 16 that dogs possess something
very like a conscience.
Dogs possess some power of self-command, and this does not
appear to be wholly the result of fear. As Braubach 17 remarks,
they will refrain from stealing food in the absence of their
master. They have long been accepted as the very type oi
fidelity and obedience. But the elephant is likewise very faith-
ful to his driver or keeper, and probably considers him as the
14 As Mr. Bain states, "effective ie *De I'Espece et de la Classe,*
u aid to a sufferer springs from sym- 1869, p. 97.
" path y proper :" ' Mental and Moral 17 * Die Darwin'sche Art-Lehre,
Science/ 3868, p. 245. 1869, s. 54.
li 'Thierkhen, B. i. s. 85.
104 The Descent of Man. Pabt i.
leader of the herd. Dr. Hooker informs me that an elephant,
which he was riding in India, became so deeply bogged that he
remained stuck fast until the next day, when he was extricated
by men with ropes. Under such circumstances elephants will
seize with their trunks any object, dead or alive, to place under
their knees, to prevent their sinking deeper in the mud ; and the
driver was dreadfully afraid lest the animal should have seized
Dr. Hooker and crushed him to death. But the driver himself,
as Dr. Hooker was assured, ran no risk. This forbearance under
an emergency so dreadful for a heavy animal, is a wonderful
proof of noble fidelity. 18
AlJjimmaJsJiyingJ^
th eir enemiesjn ^o^certjjnust indeed be in some degree faithful
to o ne another ; and those that' folio w^nMngF^gsTgaTfi some
degree obedient. WherTthe baboons in Abyssinia lp plunder a
garden, they silently follow their leader ; and if an imprudent
young animal makes a noise, he receives a slap from the others
to teach him silence and obedience. Mr. Galton, who has had
excellent opportunities for observing the half-wild cattle in S.
Africa, says, 20 that they cannot endure even a momentary separa-
tion from the herd. They are essentially slavish, and accept th«
com mon determination, ^ekih^ "non5elter~T6f tharTto be led by
any^oneox who ha^enoughJOT-irelM^to. accept the position.
The men w¥o~breaklnlEese animals for harness, watch assidu-
ously for those who, by grazing apart, shew a self-reliant dis-
position, and these they train as fore-oxen. Mr. Galton adds
that such animals are rare and valuable ; and if many were born
they would soon be eliminated, as lions are always on the look-
out for the individuals which wander from the herd.
With respect to the impulse which leads certain animals to
associate together, and to aid one another in many ways, we
may infer that in most cases they are impelled by the same
sense of satisfaction or pleasure which they experience in per-
forming other instinctive actions; or by the same sense of
dissatisfaction as when other instinctive actions are checked.
We see this in innumerable instances, and it is illustrated in a
striking manner by the acquired instincts of our domesticated
animals ; thus a young shepherd-dog delights in driving and
running round a flock of sheep, but not in worrying them ; a
young fox-hound delights in hunting a fox, whilst some other
kinds of dogs, as I have witnessed, utterly disregard foxes. What
18 See also Hooker's ' Himalayan *« See his extremely interesting
Journals,' vol. ii., 1854, p. 333. paper on < Gregariousness in Cattle,
w Brehm, < Thierleben,' B. i. s. and in Man/ 4 Macmiihin's Mir.' Feb,
76. 187J,p, 353,
uhap, IV. Moral Sense. 105
& strong feeling of inward satisfaction must impel a bird, so full
of activity, to brood day after day over her eggs. Migratory
birds aro quite miserable if stopped from migrating; perhaps
they enjoy starting on their long flight ; but it is hard to believe
that the poor pinioned goose, described by Audubon, which
started on foot at the proper time for its journey of probably
more than a thousand miles, could have felt any joy in doing so.
Some instincts are determined solely by painful feelings, as by
fear, which leads to self-preservation, and is in some cases directed
towards special enemies. No one, I presume, can analyse the
sensations of pleasure or pain. In many instances, however, it
is probable that instincts are persistently followed from the
mere force of inheritance, without the stimulus of either
pleasure or pain. A young pointer, when it first scents game,
apparently cannot help pointing. A squirrel in a cage who pats
the nuts which it cannot eat, as if to bury them in the ground,
can hardly be thought to act thus, either from pleasure or pain.
Hence the common assumption that men must be impelled to
every action by experiencing some pleasure or pain may be erro-
neous. Although a habit may be blindly and implicitly
followed, independently of any pleasure or pain felt at the
moment, yet if it be forcibly and abruptly checked, a vague
sense of dissatisfaction is generally experienced.
It has often been assumed that animals were in the first place
rendered social, and that they feel as a consequence uncomfort-
able when separated from each other, and comfortable whilst
together ; but it is a more probable view that these sensations
were first developed, fa cwfor t.^at t.hnpfi flnjmals which would
profit by Hyjn^Jnsociety, should be induced to live together,
in the l^rnlTman^^
eating were, no doubt, first acquired in order to induce animals
to eat. The feeling of pleasure from society is probably anj
extension of the parental or filial affections, since the social!
instinct seems to be developed by the young remaining for a\
long time with their parents ; an d this extension may be attri -
buted in part to habi t, but chiefly to naturaJLseLeciion. jVith_
those an imals which were benefited by living in close as s oci a tion ,
the indi viduals which took the greatest pleasure Jyajsociety
would nSest escape various dangers^ whilst those that cared
least fo r their comrades, and liveof^o litary, would perish in
gre^ejDQJimMrS, With respect TxTtKeTorigm oFthlTparenfa]
and filial affections, which apparently lie at the base of the
social instincts, we know not the steps by which they have
boen gained; but we may infer that it has been to a large
extent through natural selection. So it has almost certainly
106 Ike Descent of Man. pAitir 1.
been with the unusual and opposite feeling of hatred between
the nearest relations, as with the worker-bees which kill their
brother-drones, and with the queen-bees which kill their
daughter-queens; the desire to destroy their nearest relations
having been in this case of service to the community. Parental
affection, or some feeling which replaces it, has been developed
in certain animals extremely low in the scale, for example, in
star-fishes and spiders. It is also occasionally present in a few
members alone in a whole group of animals, as in the genus
Forficula, or earwigs.
The all-important emotion of sympathy is distinct from that
of love. A mother may passionately love her sleeping and
passive infant, but she can hardly at such times be said to feel
sympathy for it. The love of a man for his dog is distinct from
sympathy, and so is that of a dog for his master. Adam Smith
formerly argued, as has Mr. Bain recently, that the basis of
sympathy lies in our strong retentiveness of former states of
pain or pleasure. Hence, " the sight of another person en-
" during hunger, cold, fatigue, revives in us some recollection of
" these states, which are painful even in idea." We are thus
impelled to relieve the sufferings of another, in order that our
own painful feelings may be at the same time relieved. In like
manner we are led to participate in the pleasures of others. 21
But I cannot see how this view explains the fact that sympathy
is excited, in an immeasurably stronger degree, by a beloved,
than by an indifferent person. The mere sight of suffering,
independently of love, would suffice to call up in us vivid
recollections and associations. The explanation may lie in the
fact that, with all animals, sympathy is directed solely towards
the members of the same community, and therefore towards
known, and more or less beloved members, but not to all tho
individuals of the same species. This fact is not more sur-
prising than that the fears of many animals should be directed
against special enemies. Species which are not social, such as
lions and tigers, no doubt feel sympathy for the suffering of
their own young, but not for that of any other animal. With
21 See the first and striking " or others in his stead, may make
chapter in Adam Smith's * Theory " up, by sympathy and good offices
of Moral Sentiments/ Also Mr. " returned, for all the sacrifice."
Bain's * Mental and Moral Science/ But if, as appears to he the case,
1868, p. 244, and 275-282. Mr. sympathy is strictly an instinct,
ttain states, that " sympathy is, in- its exercise would give direct plea-
"■* directly, a source of pleasure to sure, in the same manner as the
" the sympathiser ;" and he accounts exercise, as before remarked, of al*
for this through reciprocity. He most every other instinct,
remarks that " the person benefited,
Chap. IV. Moral Sense, 107
mankind, selfishness, experience, and imitation, probably add,
as Mr. Bain has shewn; to the power of sympathy ; for we ar e ^>y
l ed by the hope of receiving good in return to perform acts _ y WcaL\ -
oT" sympathetic kindness to others; and sympathy^is muc h
s trengthened by habi t. In however complex a manner this"""^
feeling may have originated, as it is one of high importance to j
all those animals which aid and defend one another, it will havo I
been increased through natural selection ; for those commu- /
nities, which included the greatest number of the most sympa- (
thetic members, would flourish best, and rear the greatest \
number of offspring. ~— )
It is, however, impossible to decide in many cases whether
certain social instincts have beon acquired through natural
selection, or are the indirect result of other instincts and
faculties, such as sympathy, reason, experience, and a tendency
to imitation ; or again, whether they are simply the result of
long-continued habit. So remarkable an instinct as the placing
sentinels to warn the community of danger, can hardly have
been the indirect result of any of these faculties ; it must, there-
fore, have been directly acquired. On the other hand, the habit
followed by the males of some social animals of dfiffrndi^ g fo ft
community , and of attacking their enemies or their- ^may in
concert, may~perhaps have originated from mutual sympathy ;
but co urage7~and in most "cases strength, " must have been
previousIy ~acquired, probabl y through natur^selectionT""^
Of the various instincts and habits, some~are much stronger
than others ; that is, some either give more pleasure in their
performance, and more distress in their prevention, than others ;
or, which is probably quite as important, they are, through
inheritance,, more persistently followed, without exciting any
special feeling of pleasure or pain. "We are ourselves conscious
that some habits are much more difficult to cure or change than
others. Hence a struggle may often be observed in animals
between different instincts, or between an instinct and some
habitual disposition ; as when a dog rushes after a hare, is
rebuked, pauses, hesitates, pursues again, or returns ashamed to
his master ; or as between the love of a female dog for her young
puppies and for her master,— for she may be seen to slink away
to them, as if half ashamed of not accompanying her master.
But the most curious instance known to me of one instinct
getting the better of another, is the migratory instinct conquer-
ing the maternal instinct. The former is wonderfully strong ; a
confined bird will at the proper season beat her breast against
the wires of her cage, until it is bare and bloody. It causes
young salmon to leap out of the fresh water, in which they could
loS x The Descent of Man, Past I.
continue to exist, and thus unintentionally to commit suicide.
Every one knows how strong the maternal instinct is, leading
even timid birds to face great danger, though with hesitation,
and in opposition to the instinct of self-preservation. Neverthe-
less, the migratory instinct is so powerful, that late in the autumn
swallows, house-martins, and swifts frequently desert their
tender young, leaving them to perish miserably in their nests. 53
We can perceive that an instinctive impulse, if it be in any
way more beneficial to a species than some other or opposed
instinct, would be rendered the more potent of the two through
natural selection ; for the individuals which had it most strongly
developed would survive in larger numbers. Whether this is the
case with the migratory in comparison with the maternal instinct,
may be doubted. The great persistence, or steady action of the
former at certain seasons of the year during the whole day, may
give it for a time paramount force.
Man a social animal. — Every one will admit that man is a
social being. We see this in his dislike of solitude, and in his
wish for society beyond that of his own family. Solitary con-
finement is one of the severest punishments which can be
inflicted. Some authors suppose that man primevally lived in
single families ; but at the present day, though single families,
or only two or three together, roam the solitudes of some savage
lands, they always, as far as I can discover, hold friendly
relations with other families inhabiting the same district. Such
families occasionally meet in council, and unite for their common
defence. It is no argument against savage man being a social
animal, that the tribes inhabiting adjacent districts are almost
always at war with each other ; for the social instincts nevei
extend to all the individuals of the same species. Judging from
the analogy of the majority of the Quadrumana, it is probable
that the early ape-like progenitors of man were likewise social ;
but this is not of much importance for us. Although man, as
22 This fact, the Rev. L. Jenyns hatched. Many birds, not yet old
states (see his edition of 4 White's enough for a prolonged flight, are
Nat. Hist, of Selborne,' 1853, p. likewise deserted and left behind.
204) was first recorded by the illus- See Blackwall, * Researches in Zoo-
trious Jenner, in * Phil. Transact.* logy,' 1834, pp. 108, 118. For some
1824, and has since been confirmed additional evidence, although this
by several observers, especially by is not wanted, see Leroy, 4 Lettres
Mr. Blackwall. This latter careful Phil/ 1802, p. 217. For Swifts,
observer examined, late in the Gould's 'Introduction to the Birds
autumn, during two years, thirty- of Great Britain,' 1823, p. 5. Simi-
six nests ; he found that twelve lar cases have been observed in
contained young dead birds, five Canada by Mr. Adams ; ' Pop,
contained eggs on the point of being Science Review,' July 1873, p.
hatched, and three, aggs not nearly 283.
Chap. IV, Moral Sense. log
he now exists, has few special instincts, having lost any which
his early progenitors may have possessed, this is no reason why
he should not have retained from an extremely remote period
some degree of instinctive love and sympathy for his fellows.
We are indeed all conscious that we do possess such sympathetic
feelings ; ** but our consciousness does not tell us whether they
are instinctive, having originated long ago in the same manner
as with the lower animals, or whether they have been acquired
by each of us during our early years. A s man is a social anim al,
it is aJmxMftjcertaj^^ be
faKh ful to his com rades, an d obedient to the leader of his tribe ;
for these qualities are common to most social animals, lie would
consequently possess some capacity for self-command. He
would from an i nherited tendency be willing to defend, in
conc ert with ot hers^ his fellow-menl"an3rwould be read£ Jo aid
them in any way, which did not too greatly interfere with his
own weTIare or hi s own strong desires.
The social animals which stalidTaTthe bottom of the scale are
guided almost exclusively, and those which stand higher in the
scale are largely guided, by special instincts in the aid which
they give to the members of the same community; but they are
likewise in part impelled by mutual love and sympathy, assisted
apparently by some amount of reason. Although man, as just
remarked, has no special instincts to tell him how to aid his
fellow-men, he still has the impulse, and with his improved
intellectual faculties would naturally be much guided in this
respect by reason and experience. Instinctive sympathy would
also cause him to value highly the approbation of his fellows ;
for, as Mr. Bain has clearly shewn, 24 the love of praise and
the strong feeling of glory, and the still stronger horror of scorn
and infamy, " are due to the workings of sympathy." Conse-
quently man would be influenced in the highest degree by the
wishes, approbation, and blame of his fellow-men, as expressed
by their gestures and language. Thus the social instincts,
which must have been acquired by man in a very rude state,
and probably even by his early ape-like progenitors, still give
the impulse to some of his best actions ; but his actions are in a
higher degree determined by the expressed wishes and judgment
23 Hume remarks (' An Enquiry " of the former . . . communicates
Concerning the Principles of Morals/ "a secret joy ; the appearance ol
edit, of 1751, p. 132), "There seems " the latter . . . throws a melan-
«' a necessity for confessing that the " choly damp over the imagina-
" happiness and misery of others " tion."
u are not spectacles altogether in- 2# * Mental and Moral Science,
«• different to us, but that the view 1863, p. 254-
I IO The Descent of Man. Part L
of his fellow-men, and unfortunately very often by his own strong
selfish desires. But as love, sympathy and self-command become
strengthened by habit, and as the power of reasoning becomes
clearer, so that man can value justly the judgments of his
fellows, he will feel himself impelled, apart from any transitory
pleasure or pain, to certain lines of conduct. He might then
declare — not that any barbarian or uncultivated man could
thus think — I am the supreme judge of my own conduct, and in
the words of Kant, I will not in my own person violate the
dignity of humanity.
The more enduring Social Instincts conquer the less persistent
Instincts. — We have not, however, as yet considered the main
point, on which, from our present point of view, the whole
question of the moral sense turns. Why should a man feel that
he ought to obey one instinctive desire rather than another?
Why is he bitterly regretful, if he has yielded to a strong sense
of self-preservation, and has not risked his life to save that of a
fellow-creature ? or why does he regret having stolen food from
hunger ?
# I t jj evident in t hqiLratJDla.c^ that mtlLmj^nMndthe instinc-
ti ve impul ses have different degrees of strength ; a savage will
ris k his own life to save that oL amember of the same community,
but wjlljse ijvhonxin^fferent about a stranger: a young and
timid mother urged by the maternal instinct will, without a
moment's hesitation, run the greatest danger for her own infant,
but not for a mere fellow-creature. Nevertheless many a
civilized man, or even boy, who never before risked his life for
another, but full of courage and sympathy, has diregarded
the instinct of self-preservation, and plunged at once into a
torrent to save a drowning man, though a stranger. In this case
man is impelled by the same instinctive motive, which made the
heroic little American monkey, formerly described, save his
keeper, by attacking the great and dreaded baboon. Such
actions as the above appear to be the simple result of the greater
strength of the social or maternal instincts than that of any
other instinct or motive; for they are performed too instan-
taneously for reflection, or for pleasure or pain to be felt at the
time ; though, if prevented by any cause, distress or even misery
might be felt. In a timid man, on the other hand, the instinct
of self-preservation might be so strong, that he would be unable
to force himself to run any such risk, perhaps not even for his
own child.
I am aware that some persons maintain that actions performed
impulsively, as in the above cases, do not come under the
doinizion of the moral sense, and cannot b€ called moral. The^
Ohap. IV. Moral Sense. ill
confine this term to actions done deliberately, after a victory
over opposing desires, or when prompted by some exalted
motive. But it appears scarcely possible to draw any clear line
of distinction of this kind. 25 Ajs far as exalted motives are
concerned, many instances have been recorded of savages,
destitute of any feeling of general benevolence towards mankind
and not guided by any religious motive, who have deliberatel y
sacrifice d their liv es as prisoners, 26 rather than betray their
comra3e§.; and surely their conduct ougEFto^W:X!OnldaeTOtTnr
moral. As far as deliberation, and the victory over opposiDg
motives are concerned, animals may be seen 3TouBlmgn5itween
opposed ins line Ls, in res<ij^ng_tneir otis^nn^_^or comrades <T~
from^flallgerl yet their"" actions, though done for the good of
others, are not called moral. Moreover, anything performed
very often by us, will at last be done without deliberation or
hesitation, and can then hardly be distinguished from an
instinct; yet surely no one will pretend that such an action
ceases to be moral. On the contrary, we all feel that an act
cannot be considered as perfect, or as performed in the most
noble manner, unless it be done impulsively, without deliberation
or effort, in the same manner as by a man in whom the requisite
qualities are innate. He who is forced to overcome his fear or
want of sympathy before he acts, deserves, however, in one way
higher credit than the man whose innate disposition leads him
to a good act without effort. As we cannot distinguish between
motives, we rank all actions of a certain class as moral, if
performed by a moral being. A moral being is one who is \
capable of comparing his past and future actions or motives, and I
of approving or disapproving of them. "We have no reason to 1
suppose that any of the lower animals have this capacity ; | *
therefore, when a Newfoundland dog drags a child out of the f
water, or a monkey faces danger to rescue its comrade, or takes f
charge of an orphan monkey, we do not call its conduct moral. \
But in the case of man, who alone can with certainty be ranked
as a moral being, actions of a certain class are called moral,
whether performed deliberately, after a struggle with opposing
25 I refer here to the distinction " material and formal morality 13
between what has been called ma- " as irrelevant as other such dis-
terial and formal morality. I am " tinctions."
glad to find that Prof. Huxley (*Cri- 26 I have given one 6uch case,
tiaues and Addresses/ 1873, p. 287) namely of three Patagonian Indians
takes the same view on this subject who preferred being shot, one after
as I do. Mr. Leslie Stephen re- the other, to betraying the plans of
marks (* Essays on Freethinking and their companions in war (' Jourml
Plain Speaking 1873, p. 83), " the of Researal«s,' 1845, p. 103).
** metaphysical \Lstinetion between
112 ' The Descent of Man. Pabt L
motives, or impulsively through instinct, or from the effects of
slowly-gained habit.
But to return to our more immediate subject. Although
some instincts are more powerful than others, and thus lead to cor-
responding actions, yet it is untenable, that in man the social
instincts (including the love of praise and fear of blame) possess
greater strength, or have, through long habit, acquired greater
strength than the instincts of self-preservation, hunger, lust,
vengeance, &c. Why then does man regret, even though trying
to banish such regret, that he has followed the one natural
impulse rather than the other ; and why does he further feel
that he ought to regret his conduct ? Man in this respect differs
profoundly from the lower animals. Nevertheless we can, I think,
see with some degree of clearness the reason of this difference.
Man, from the activity of his mental faculties, cannot avoid
reflection : past impressions and images are incessantly and
clearly passing through his mind. Now with those animals
which live permanently in a body, the social instincts are ever
present and persistent. Such animals are always ready to utter
the danger-signal, to defend the community, and to give aid to
their fellows in accordance with their habits ; they feel at all
times, without the stimulus of any special passion or desire,
some degree of love and sympathy for them ; they are unhappy
if long separated from them, and always happy to be again in
their company. So it is with ourselves. Even when we are
quite alone, how often do we think with pleasure or pain of
what others think of us, — of their imagined approbation or
disapprobation ; and this all follows from sympathy, a funda-
mental element of the social instincts. A man who possessed
no trace of such instincts would be an unnatural monster. On
the other hand, the desire to satisfy hunger, or any passion such
as vengeance, is in its nature temporary, and can for a time be
fully satisfied. Nor is it easy, perhaps hardly possible, to call
up with complete vividness the feeling, for instance, of hunger ;
nor indeed, as has often been remarked, of any suffering. The
instinct of self-preservation is not felt except in tho presence of
danger ; and many a coward has thought himself brave until he
has met his enemy face to face. The wish for another man's
property is perhaps as persistent a desire as any that can be
named; but even in this case the satisfaction of actual pos-
session is generally a weaker feeling than the desire : many a
thief, if not a habitual one, after success has wondered why ho
stole some article. 27
2r Enmity or hatred seems also perhaps more so than any othsi
to he a highly persistent feeling, that can *e named. Ebvv is da-
Chap. IV. Moral Sense. 1 1 3
A man cannot prevent past impressions often repassing through
his mind ; he will thus be driven to make a comparison between
the impressions of past hunger, vengeance satisfied, or danger
shunned at other men's cost, with the almost ever-present
instinct of sympathy, and with his early knowledge of what
others consider as praiseworthy or blameable. This knowledge
cannot be banished from his mind, and from instinctive sympathy
is esteemed of great moment. He will then feel as if he had
been baulked in following a present instinct or habit, and this
with all animals causes dissatisfaction, or even misery.
The above case of the swallow affords an illustration, though
of a reversed nature, of a temporary though for the time strongly
persistent instinct conquering another instinct, which is usually
dominant over all others. At the proper season these birds
seem all day long to be impressed with the desire to migrate ;
their habits change ; they become restless, are noisy, and con-
gregate in flocks. Whilst the mother-bird is feeding, or brooding
over her nestlings, the maternal instinct is probably stronger
than the migratory ; but the instinct which is the more persis-
tent gains the victory, and at last, at a moment when her young
ones are not in sight, she takes flight and deserts them. When
arrived at the end of her long journey, and the migratorj
instinct has ceased to act, what an agony of remorse the bird
would feel, if, from being endowed with great mental activity,
she could not prevent the image constantly passing through her
mind, of her young ones perishing in the bleak north from cold
and hunger.
fined as hatred of another for some had done him an injury and had
excellence or success; and Bacon become his enemy. Nor is it pro-
insists (Essay ix.), '•' Of all other bable that the primitive conscience
" affections envy is the most im- would reproach a man fcr injuring
" portiine and continual." Dogs are his enemy : rather it would re-
very apt to hate both strange men proach him, if he had not revenged
and strange dogs, especially if they himself. To do good in return for
live near at hand, but do not belong evil, to love your euemy, is a height
to the same family, tribe, or clan ; of morality to which it may be
this feeling would thus seem to be doubted whether the social instincts
innate, and is certainly a most per- would, by themselves, have ever led
sisteat one. It seems to be the us. It is necessary that these in-
complement and converse of the stincts, together with sympathy,
true social instinct. From what should have been highly cultivated
we hear of savages, it would appear and extended by the aid of reason,
that something of the same . kind instruction, and the love or fear of
holds good with them. If this be God, before any such golden rule
to, it would be a small step in would ever be thought of and
any one to transfer such feelings to obeyed.
aav ir. ember of the same tribe if he
1 14 The Descent of Man. p A f£
At the moment of action, man will no doubt be apt to follow
the stronger impulse; and though this may occasionally
prompt him to the noblest deeds, it will more commonly lead
him to gratify his own desires at the expense of other men.
But after their gratification, when past and weaker impressions
are judged by the ever-enduring social instinct, and by his deep
regard for the good opinion of his fellows, retribution will surely
come. He will then feel remorse, repentance, regret, or shame
this latter feeling, however, relates almost exclusively to the
judgment of others. He will consequently resolve more or less
firmly to act differently for the future ; and this is conscience ; for
conscience looks backwards, and serves as a guide for the future.
The nature and strength of the feelings which we call regret,
shame, repentance or remorse, depend apparently not only on
; tha strength of the violated instinct, but partly on the strength
of the temptation, and often still more on the judgment of
our fellows. How far each man values the appreciation of
others, depends on the strength of his innate or acquired
feeling of sympathy ; and on his own capacity for reasoning out
the remote consequences of his acts. Another element is most
important, although not necessary, the reverence or fear of the
Gods, or Spirits believed in by each man: and this applies
especially in cases of remorse. Several critics have objected
that though some slight regret or repentance may be explained
by the view advocated in this chapter, it is impossible thus to
account for the soul-shaking feeling of remorse. But I can see
little force in this objection. My critics do not define what
they mean by remorse, and I can find no definition implying
more than an overwhelming sense of repentance. Kemorso
seems to bear the same relation to repentance, as rage does to
anger, or agony to pain. It is far from strange that an instinct
so strong and so generally admired, as maternal love, should, if
disobeyed, lead to the deepest misery, as soon as the impression
of the past cause of disobedience is weakened. Even when an
action is opposed to no special instinct, merely to know that our
friends and equals despise us for it is enough to cause great
misery. Who can doubt that the refusal to fight a duel through
fear has caused many men an agony of shame ? Many a Hindoo,
tt is said, has been stirred to the bottom of his soul by having
partaken of unclean food. Here is another case of what must, I
think, be called remorse. Br. Landor acted as a magistrate in
West Australia, and relates, 28 that a native on his farm, after
losing one of his wives from disease, came and said that " he was
w < Insanity in Relation to Lavr;' Ontario, United States, 1871, p. U.
Ohai\ IV. Moral Sense. 1 1 5
" going to a distant tribe to spear a woman, to satisfy his sense
'• of duty to his wife. I told him that if he did so, I would
" send him to prison for life. He remained about the farm for
" som3 months, but got exceedingly thin, and complained that
" he could not rest or eat, that his wife's spirit was haunting
" him, because he had not taken a life for hers. I was in-
ct exorable, and assured him that nothing should save him if he
" did." Nevertheless the man disappeared for more than a year,
and then returned in high condition ; and his other wife told
Dr. Landor that her husband had taken the life of a woman
belonging to a distant tribe; but it was impossible to obtain
legal evidence of the act. The breach of a rule held sacred by
the tribe, will thus, as it seems, give rise to the deepest feelings,
—and this quite apart from the social instincts, excepting in so
far as the rule is grounded on the judgment of the community.
How so many strange superstitions have arisen throughout the
world we know not ; nor can we tell how some real and great
crimes, such as incest, have come to be held in an abhorrence
(which is not however quite universal) by the lowest savages. It
is even doubtful whether in some tribes incest would be looked on
with greater horror, than would the marriage of a man with a
woman bearing the same name, though not a relation. "To
" violate this law is a crime which the Australians hold in the
" greatest abhorrence, in this agreeing exactly with certain
" tribes of North America. When the question is put in either
" district, is it worse to kill a girl of a foreign tribe, or to marry
" a girl of one's own, an answer just opposite to ours would be
given without hesitation." 29 We may, therefore, reject the
belief, lately insisted on by some writers, that the abhorrence of
incest is due to our possessing a special God -implanted con-
science. On the whole it is intelligible, that a man urged by
so powerful a sentiment as remorse, though arising as above
explained, should be led to act in a manner, which he has been
taught to believe serves as an expiation, such as delivering
himself up to justice.
Man prompted by his conscience, will through long habit \
acquire such perfect self-command, that his desires and passions
will at last yield instantly and without a struggle to his social 1
sympathies and instincts, including his feeling for the judgment of
his fellows. The still hungry, or the still revengeful man will not
think of stealing food, or of wreaking his vengeance. It is possible
or as we shall hereafter see, even probable, that the habit of self-
command may, like other habits, be inherited. Thus at last man
» E. B. Tylor in * Contemporary. Eavisw,' April, 1873, p. 707.
I 2
1 1 6 Tlie Descent of Man. Fart I
comes to feel, through acquired and perhaps inherited habit, that
it is best for him to obey his moro persistent impulses. The
imperious word ought seems merely to imply the consciousness of
the existence of a rule of conduct, however it may have
originated. Formerly it must have been often vehemently
urged that an insulted gentleman ought to fight a duel. We
even say that a pointer ought to point, and a retriever to
retrieve game. If they fail to do so, they fail in their duty
and act wrongly.
If any desire or instinct leading to an action opposed to the
good of others still appears, when recalled to mind, as strong
as, or stronger than, the social instinct, a man will feel no keen
regret at having followed it ; but he will be conscious that if his
conduct were known to his fellows, it would meet with their
disapprobation; and few are so destitute of sympathy as not to
feel discomfort when this is realised. If he has no such
sympathy, and if his desires leading to bad actions are at the
time strong, and when recalled are not over-mastered by the
persistent social instincts, and the judgment of others, then he
is essentially a bad man; 30 and the sole restraining motive left
is the fear of punishment, and the conviction that in the long
run it would be best for his own selfish interests to regard the
good of others rather than his own.
It is obvious that every one may with an easy conscience
gratify his own desires, if they do not interfere with his sociaJ
instincts, that is with the good of others ; but in order to be quite
free from self-reproach, or at least of anxiety, it is almost neces-
sary for him to avoid the disapprobation, whether reasonable or
not, of his fellow-men. Nor must he break through the fixed
habits of his life, especially if these are supported by reason ;
for if he does, he will assuredly feel dissatisfaction. He must
likewise avoid the reprobation of the one God or gods in whom,
according to his knowledge or superstition, he may believe ; but
in this case the additional fear of divine punishment often
supervenes.
The strictly Social Virtues at first alone regarded. — The above
view of the origin and nature of the moral sense, which tells us
what we ought to do, and of the conscience which reproves us if
we disobey it, accords well with what we see of the early and
undeveloped condition of this faculty in mankind. The virtues
which must be practised, at least generally, by rude men, so
30 Dr. Prosper Despine, in his many curious cases of the worst
* V*sychologie Naturelle/ 1868 (torn. criminals, who apparently have been
i p. 243; torn. ii. ;. 169} gives entirely destitute of conscience-
Chap. 1 V. Moral Sense. 117
that they may associate in a body, are those which are still
recognised as the most important. B ut they are j ^rantiaftd
almost exclusively in relation to the men of the same tribe ; and
their oppQgiie s_are not regarded jis^crimes in relation to the men
of other tribes. N o tribe could hold together if murder,
robbery, treachery, &c, were common; consequently such
crimes within the limits of the same tribe "are branded with
"everlasting infamy ;" al but excite no such sentiment beyond
these limits. A North-American Indian is well pleased with
himself, and is honoured by others, when he scalps a man of
another tribe ; and a Dyak cuts off the head of an unoffending
person, and dries it as a trophy. The murder of infants has
prevailed on the largest scale throughout the world, 32 and has
met with no reproach ; but infanticide, especially of females, has
been thought to be good for the tribe, or at least not injurious.
Suicide during former times was not generally considered as a
crime, 33 but rather, from the courage displayed, as an honourable
act ; and it is still practised by some semi-civilised and savage
nations without reproach, for it does not obviously concern
others of the tribe. It has been recorded that an Indian Thug
conscientiously regretted that he had not robbed and strangled
as many travellers as did his father before him. In a rude state
of civilisation the robbery of strangers is, indeed, generally
considered as honourable.
Slavery, although in some ways beneficial during ancient
times, 84 is a great crime ; yet it was not so regarded until quite
recently, even by the most civilized nations. And this was
especially the case, because the slaves belonged in general to a
race different from that of their masters. As barbarians do not
regard the opinion of their women, wives are commonly treated
like slaves. Most savages are utterly indifferent to the sufferings
of strangers, or even delight in witnessing them. It is well
31 See an able article in the of European Morals/ vol. i. 1869,
North British Review/ 1867, p. p. 223. With respect to savages,
395. See also Mr. W. Bagehot's Mr. Winwood Reade informs me
articles on the Importance of Obe- that the negroes of West Africa
dience and Coherence to Primitive often commit suicide. It is well
Man, in the ' Fortnightly Review,* known how common it was amongst
1367, p. 529, and 1868, p. 457, &c. the miserable aborigines of South
99 The fullest account which I America, after the Spanish conquest,
have met with is by Dr. Gerland, in For New Zealand, see the voyage ot
his ' Ueber dan Aussterben der the " Novara," and for the Aleutian
Naturvolker/ 1868; but 1 shall Islands, Mtiller, as quoted by Hou-
have to recur to the subiect of zeau, * Les Facultds Mentales/ &c^
infanticide in a future chapter. torn. ii. p. 136.
*• See the very interesting discus- ** See Mr. Bagehot, ' Piysics and
won en Suicide in Lecky's * History Politic*/ 1872, p. 72.
II 8 The Descent pf Man. Taut l
known that the women and children of the North-American
Indians aided in torturing their enemies. Some sayages take a
horrid pleasure in cruelty to animals, 35 and humanity is an
unknown virtue. Nevertheless, besides the family affections,
kindness is common, especially during sickness, between the
members of the same tribe, and is sometimes extended beyond
these limits. Mungo Park's touching account of the kindness of
the negro women of the interior to him is well known. Many
instances could be given of the noble fidelity of savages towards
each other, but not to strangers ; common experience justifies
the maxim of the Spaniard, "Never, never trust an Indian."
There cannot be fidelity without truth ; and this fundamental
virtue is not rare between the members of the same tribe : thus
Miungo Park heard the negro women teaching their young
children to love the truth. This, again, is one of the virtues
which becomes so deeply rooted in the mind, that it is sometimes
practised by savages, even at a high cost, towards strangers ; but
to lie to your enemy has rarely been thought a sin, as the history
of modern diplomacy too plainly shews. As soon as a tribe has
a recognised leader, disobedience becomes a crime, and even
abject submission is looked at as a sacred virtue.
As during rude times no man can be useful or faithful to his
tribe without courage, this quality has universally been placed
in the highest rank; and although in civilised countries a
good yet timid man may be far more useful to the community
than a brave one, we cannot help instinctively honouring the
latter above a coward, however benevolent. Prudence, on the
other hand, which does not concern the welfare of others, though
a very useful virtue, has never been highly esteemed. As nc
man can practise the virtues necessary for the welfare of his
tribe without self-sacrifice, self-command, and the power ot
endurance, these qualities have been at all times highly and
most justly valued. The American savage voluntarily submits
to the most horrid tortures without a groan, to prove and
streDgthen his fortitude and courage; and we cannot help
admiring him, or even an Indian Fakir, who, from a foolish
religious motive, swings suspended by a hook buried in his
flesh.
The other so called self-regarding virtues, which do not
obviously, though they may really, affect the welfare of the tribe,
have never been esteemed by savages, though now highly
appreciated by civilised nations. The greatest intemperance
• a See, for instance, Mr. Hamilton's account of the Kaffirs, * Anthro-
pological Review/ ] 870, p. xv.
Chap. IV, Moral Sense. 1 1 9
is no reproach with savages. Utter licentiousness, and un-
natural crimes, prevail to an astounding extent. 36 As soon,
however, as marriage, whether polygamous, or monogamous,
becomes common, jealousy will lead to the inculcation of female
virtue; and this, being honoured, will tend to spread to the
unmarried females. How slowly it spreads to the male sex,
we see at the present dav Chastity eminently requires self-
command; therefore it has been honoured from a very early
period in the moral history of civilised man. As a consequence
of this, the senseless practice of celibacy has been ranked from a
remote period as a virtue. 87 The hatred of indecency, which
appears to us so natural as to be thought innate, and which is
so valuable an aid to chastity, is a modern virtue, appertaining
exclusively, as Sir G-. Staunton remarks, 38 to civilised life. This
is shewn by the ancient religious rites of various nations, by the
drawings on the walls of Pompeii, and by the practices of many
savages.
We have now seen that actions are regarded by savage_s^ancl
we re probably so regarded by primevaT man, as good or^ bad, 1
solely as_ they obviously affect the weliS^MJBfinE]S^iiM..that
of_ the_sjpecies^BOE, that f an individual membei '_of , the tribe.
This conclusion agrees well with the belief that the so-called
moral sense is aboriginally derived from the social instincts, for
both relate at first exclusively to the community. The chief
causes of the low morality of savages, as judged by our
standard, are, firstly, the confinement of sympathy to the same
tribe. Secondly, powers of reasoning insufficient to recognise
the bearing of many virtues, especially of the self-regarding
virtues, on the general welfare of the tribe. Savages, for
instance, fail to trace the multiplied evils consequent on a
want of temperance, chastity, &c. And, thirdly, weak power
of self-command ; for this power has not been strengthened
through long-continued, perhaps inherited, habit, instruction and
religion.
I have entered into the above details on the immorality of
savages, 39 because some authors have recently taken a high view
of their moral nature, or have attributed most of their crimes to
mistaken benevolence. 40 These authors appear to rest their
36 Mr. M'Lennan lias given 38 'Embassy to China,* vol. U. p.
('Primitive Marriage,' 1865, p. 348.
176) a good collection of ficts on 39 See on this subject copious
this head. evidence in Chap. vii. of Sir J. Lub-
37 Lecky, 'History of European bock, ' Origin of Civilisation,' 1870.
Mcra}?/ vol 1. 1869, p. 109. 40 For instance Lecky, <Hbt
European Moral*,' vol. i. p. 124.
1 20 Tke Descent of Man Part I.
conclusion on savages possessing those virtues which are sor«
viceable, or even necessaiy, for the existence of the family and of
the tribe,— qualities which they undoubtedly do possess, and often
in a high degree.
Concluding Remarks. — It was assumed formerly by philosophers
of the derivative 41 school of morals that the foundation of morality
lay in a form of Selfishness ; but more recently the " Greatest
" happiness principle " has been brought prominently forward.
Tt is, however, more correct to speak of the latter principle as
the standard, and not as the motive of conduct. Nevertheless, all
the authors whose works I have consulted, with a few excep-
tions, 42 write as if there must be a distinct motive for every
action, and that this must be associated with some pleasure or
displeasure. But man seems often to act impulsively, that is
from instinct or long habit, without any consciousness of pleasure,
in the same manner as does probably a bee or ant, when it
blindly follows its instincts. Under circumstances of extreme
peril, as during a fire, when a man endeavours to save a fellow-
creature without a moment's hesitation, he can hardly feel
pleasure ; and still less has he time to reflect on the dissatisfaction
which he might subsequently experience if he did not make the
attempt. Should he afterwards reflect over his own conduct, he
would feel that there lies within him an impulsive power widely
different from a search after pleasure or happiness; and this
seems to be the deeply planted social instinct.
In the case of the lower animals it seems much more appro-
priate to speak of their social instincts, as having been developed
41 This term is used in an able " ness extra-regarding impulse, di-
m-tide in the * Westminster Review,' " rected towards something that is
Oct. 1869, p. 498. For the " Greatest "not pleasure; that in many cases
" happiness principle," see J. S. Mill, " the impulse is so far incompatible
* Utilitarianism/ p. 17. "with the self-regaiding that the
42 Mill recognises ('System of " two do not easily co-exist in the
Logic/ vol. ii. ? p. 422) in the clearest " same moment of consciousness. 1 '
manner, that actions may be per- A dim feeling that our impulses do
formed through habit without the not by any means always arise from
anticipation of pleasure. Mr. H. any contemporaneous or anticipated
Sidgwick also, in his Essay on pleasure, has, I cannot but think,
Pleasure and Desire (' The Con- been one chief cause of the accept-
temporary Review/ April 1872, p. ance of the intuitive theory of
671), remarks: "To sum up, in morality, and of the rejection of the
" contravention of the doctrine that utilitarian or " Greatest happiness "
" our conscious active impulses are theory. With respect to the latter
" always directed towards the pro- theory, the standard and the motive
" duction of agreeable sensations in of conduct have no doubt often beeji
M ourselves, I would maintain that confused, but they are really h
u we find everywhere is conscious- some degree blended.
Ohap. rv . Moral Sense. 1 2 1
for the general good rather than for the general happiness of the
species. The term, general good, may be defined as the rearing
"""of the greatest number of individuals in full vigour and health,
with all their faculties perfect, under the conditions to which
they are subjected. As the social instincts both of man and the
lower animals have no doubt been developed by nearly the same
steps, it would be advisable, if found practicable, to use the
same definition in both cases, and to take as the standard of
morality, the general good or welfare of the community, rather
than the general happiness ; but this definition would perhaps
require some limitation on account of political ethics.
When a man risks his life to save that of a fellow-creature, it
seems also more correct to say that he acts for the general good,
rather than for the general happiness of mankind. No doubt
the welfare and the happiness of the individual usually coincide ;
and a contented, happy tribe will flourish better than one that
is discontented and unhappy. We have seen that even at an
early period in the history of man, the expressed wishes of tho
community will have naturally influenced to a large extent the
conduct of each member; and as all wish for happiness, the
"greatest happiness principle " will have become a most im-
portant secondary guide and object ; the social instinct, however,
together with sympathy (which leads to our regarding the
approbation and disapprobation of others), having served as the
primary impulse and guide. Thus the reproach is removed of
laying the foundation of the noblest part of our nature in the
base principle of selfishness; unless, indeed, the satisfaction
which every animal feels, when it follows its proper instincts,
and the dissatisfaction felt when prevented, be called selfish.
The wishes and opinions of the members of the same community,
expressed at first orally, but later by writing also, either form
the sole guides of our conduct, or greatly reinforce the social
instincts ; such opinions, however, have sometimes a tendency
directly opposed to these instincts. This latter fact is well
exemplified by the Law of Honour, that is, the law of the opinion
of our equals, and not of all our countrymen. The breach of
this law, even when the breach is known to be strictly accordant
with true morality, has caused many a man more agony than a
real crime. We recognise the same influence in the burning
sense of shame which most of us have felt, even after the interval
of years, when calling to mind some accidental breach of a
trifling, though fixed, rule of etiquette. The judgment of the
community will generally be guided by some rude experience of
what is best in the long run for all the members ; but this judg-
ment will not rarely err from ignorance and weak powers of
122 The Descent of Man. Part I.
reasoning. Hence the strangest customs and superstitions, in
complete opposition to the true welfare and happiness of man-
kind, have become all-powerful throughout the world. We see
this in the horror felt by a Hindoo who breaks his caste, and
in many other such cases. It would be difficult to distinguish
between the remorse felt by a Hindoo who has yielded to the
temptation of eating unclean food, from that felt after committing
a theft ; but the former would probably be the more severe.
How so many absurd rules of conduct, as well as so many
absurd religious beliefs, have originated, we do not know ; noi
how it is that they have become, in all quarters of the world, so
deeply impressed on the mind of men; but it is worthy of
remark that a belief constantly inculcated during the early years
of life, whilst the brain is impressible, appears to acquire almost
the nature of an instinct ; and the very essence of an instinct is
that it is followed independently of reason. Neither can we say
why certain admirable virtues, such as the love of truth, are
much more highly appreciated by some savage tribes than by
others ; 43 nor, again, why similar differences prevail even amongst
highly civilised nations. Knowing how firmly fixed many
strange customs and superstitions have become, we need feel no
surprise that the self-regarding virtues, supported as they are by
reason, should now appear to us so natural as to be thought
innate, although they were not valued by man in his early
condition.
Notwithstanding many sources of doubt, man can generally
and readily distinguish between the higher and lower moral
rules. The higher are founded on the social instincts, and relate
to the welfare of others. They are supported by the approbation
of our fellow-men and by reason. The lower rales, though some
of them when implying self-sacrifice hardly deserve to be called
lower, relate chiefly to self, and arise from public opinion, ma-
tured by experience and cultivation ; for they are not practised
by rude tribes.
As man advances in civilisation, and small tribes are united
into larger communities, the simplest reason would tell each
individual that he ought to extend his social instincts and
sympathies to all the members of the same nation, though
personally unknown to him. This point being once reached,
there is only an artificial barrier to prevent his sympathies
extending to the men of all nations and races. If, indeed, such
men are separated from him by great differences in appearance
43 Good instances are given by in his « Contributions to th<i Theon
Mr. Wallace in « Scientific Opinion/ of Natural Select x>n ' 1£70, p. 353
Sept. 15, 1869 ; and more fully r
Ceap. IV, Moral Sense. 121
or habits, experience unfortunately shews us how long it is,
before we look at them as our fellow-creatures. Sympathy
beyond the confines of man, that is, humanity to the lower
animals, seems to be one of the latest moral acquisitions. It is
apparently unfelt by savages, except towards their pets. How
little the old Eomans knew of it is shewn by their abhorrent
gladiatorial exhibitions. The very idea of humanity, as far as I
could observe, was new to most of the Gauchos of the Pampas.
This virtue, one of the noblest with which man is endowed,
seems to arise incidentally from our sympathies becoming more
tender and more widely diffused, until they are extended to all
sentient beings. As soon as this virtue is honoured and practised
by some few men, it spreads through instruction and example
to the young, and eventually becomes incorporated in public
opinion.
The highest possible stage in moral culture is when we re-
cognise that we ought to control our thoughts, and " not even in
" inmost thought to think again the sins that made the past so
" pleasant to us." 44 Whatever makes any bad action familiar to
the mind, renders its performance by so much the easier. As
Marcus Aurelius long ago said, "Such as are thy habitual
" thoughts, such also will be the character of tby mind ; for the
" soul is dyed by the thoughts." 45
Our great philosopher, Herbert Spencer, has recently explained
his views on the moral sense. He says, 46 "I believe that the
" experiences of utility organised and consolidated through all
" past generations of the human race, have been producing
" corresponding modifications, which, by continued transmission
" and accumulation, have become in us certain faculties of
" moral intuition— certain emotions responding to right and
" wrong conduct, which have no apparent basis in the individual
" experiences of utility." There is not the least inherent
improbability, as it seems to me, in virtuous tendencies being
more or less strongly inherited ; for, not to mention the various
dispositions and habits transmitted by many of our domestic
animals to their offspring, I have heard of authentic cases in
which a desire to steal and a tendency to lie appeared to run
in families of the upper ranks ; and as stealing is a rare crime i*\
the wealthy classes, we can hardly account by accidental coinci-
dence for the tendency occurring in two or three members of
44 Tennyson, ' Idylls of the King,' Aurelius was born A.D. 121.
p. 244. 46 Letter to Mr. Mill in Bain's
45 * The Thoughts of the Emperor * Mental and Moral Science/ 1 868
M. Aurelius Antoninus," Eng. trans- p. 722.
hU 2nd edit,, 1869, p. 112. Mavcis
124 The Descent of Man. Part!
the same family. If bad tendencies are transmitted, it is pro-
bable that good ones are likewise transmitted. That the state
of the body by affecting the braiij, has great influence on the
moral tendencies is known to most of those who have suffered
from chronic derangements of the digestion or liver. The same
fact is likewise shewn by the " perversion or destruction of the
" moral sense being often one of the earliest symptoms of mental
* f derangement;" 47 and insanity is notoriously often inherited.
Except through the principle of the transmission of moral ten-
dencies, we cannot understand the differences believed to exist in
this respect between the various races of mankind.
Even the partial transmission of virtuous tendencies would
be an immense assistance to the primary impulse derived directly
and indirectly from the social instincts. Admitting for a moment
that virtuous tendencies are inherited, it appears probable, at
least in such cases as chastity, temperance, humanity to animals,
&c, that they become first impressed on the mental organization
through habit, instruction and example, continued during
several generations in the same family, and in a quite subordinate
degree, or not at all, by the individuals possessing such virtues
havmg_jn£CJ3£ded best in the struggle for fife. ISrychief source
of doubt with respect to any such inheritance, is that senseless
customs, superstitions, and tastes, such as the horror of a Hindoo
for unclean food, ought on the same principle to be transmitted.
I have not met with any evidence in support of the transmission
of superstitious customs or senseless habits, although in itself it
is perhaps not less probable than that animals should acquire
inherited tastes for certain kinds of food or fear of certain foes.
Finally the social instincts, which no doubt were acquired by
man as by the lower animals for the good of the community,
will from the first have given to him some wish to aid his
fellows, some feeling of sympathy, and have compelled him to
regard their approbation and disapprobation. Such impulses
will have served him at a very early period as a rude rule of
right and wrong. But as man gradually advanced in intellectual
power, and was enabled to trace the more remote consequences
of his actions; as he acquired sufiicient knowledge to reject
baneful customs and superstitions; as he regarded more and
more, not only the welfare, but the happiness of his fellow-men ;
as from habit, following on beneficial experience, instruction
and example, his sympathies became more tender and widely
diffused, extending to men of all races, to the imbecile, maimedf
47 Maudsley, ' Body and Mind,' 1870, p. 60.
Chap. IV. Summary. t2£
and other useless members of society, and finally to the lower
animals, — so would the standard of his morality rise higher and
higher. And it is admitted by moralists of the derivative
school and by some intuitionists, that the standard of morality
has risen since an early period in the history of man. 48
As a struggle may sometimes be seen going on between the
various instincts of the lower animals, it is not surprising that
there should be a struggle in man between his social instincts,
with their derived virtues, and his lower, though momentarily
stronger impulses or desires. This, as Mr. Galton 49 has remarked,
is all the less surprising, as man has emerged from a state of
barbarism within a comparatively recent period. After having
yiolded to some temptation we feel a sense of dissatisfaction,
shame, repentance, or remorse, analogous to the feelings caused
by other powerful instincts or desires, when left unsatisfied or
baulked. We compare the weakened impression of a past
temptation with the ever present social instincts, or with habits,
gained in early youth and strengthened during our whole lives,
until they have become almost as strong as instincts. If with
the temptation still before us we do not yield, it is because
either the social instinct or some custom is at the moment
predominant, or because we have learnt that it will appear to us
hereafter the stronger, when compared with the weakened im-
pression of the temptation , and we realise that its violation would
cause us suffering. Looking to future generations, there is no
cause to fear that the social instincts will grow weaker, and we
may expect that virtuous habits will grow stronger, becoming
perhaps fixed by inheritance. In this case the struggle between
our higher and lower impulses will be less severe, and virtue
will be triumphant.
Summary of the last two Chapters. — There can be no doubt that
the difference between the mind of the lowest man and that of
the highest animal is immense. An anthropomorphous ape, if
he could take a dispassionate view of his own case, would admit
that though he could form an artful plan to plunder a garden —
though he could use stones for fighting or for breaking open
nuts, yet that the thought of fashioning a stone into a tool was
48 A writer in the * North British coincide therein.
Review* (July 1869, p. 531), well * 9 See his remarkable work on
capable of forming a sound judg- * Hereditary Geni»\s/ 1869, p. 349.
ment, expresses himself strongly in The Duke of Argyll (* Primeval
favour of this conclusion. Mr. Man/ 1869, p. 188) has some good
Lecky (* Hist, of Morals/ vol. i. p. remarks on the contest in man'i
143) seems to a certain extent to nature between right and wrong.
i 26 The Descent of Man. Vkm I.
qui to Uiyond his scope. Still less, as he would admit, could he
follow out a train of metaphysical reasoning, or solve a mathe-
matical problem, or reflect on GdS, or admire a grand natural
scene. Some apes, however, would probably declare that they
could and did admire the beauty of the coloured skin and fur of
their partners in marriage. They would admit, that though they
could make other apes understand by cries some of their per-
ceptions and simpler wants, the notion of expressing definite ideas
by definite sounds had never crossed their minds. They might
insist that they were ready to aid their fellow-apes of the same
troop in many ways, to risk their lives for them, and to take
charge of their orphans ; but they would be forced to acknow-
ledge that disinterested love for all living creatures, the mos 4 ,
noble attribute of man, was quite beyond their comprehension.
Nevertheless the difference in mind between man and the
higher animals, great as it is, certainly is one of degree and not
of kind. We have seen that the senses and intuitions, the
various emotions and faculties, such as love, memory, attention,
curiosity, imitation, reason, &c, of which man boasts, may be
found in an incipient, or even sometimes in a well- developed
condition, in the lower animals. They are also capable of some
inherited improvement, as we see in the domestic dog compared
with the wolf or jackal. If it could be proved that certain high
mental powers, such as the formation of general concepts, self-con-
sciousness, &c, were absolutely peculiar to man, which seems
extremely doubtful, it is not improbable that these qualities are
merely the incidental results of other highly-advanced intel-
lectual faculties; and these again mainly the result of the
continued use of a perfect language. At what age does the
new-born infant possess the power of abstraction, or become
self-conscious, and reflect on its own existence ? We cannot
answer ; nor can we answer in regard to the ascending organic
scale. The half-art, half-instinct of language still bears the
stamp of its gradual evolution. The ennobling belief in God is
not universal with man; and the belief in spiritual agencies
naturally follows from other mental powers. The moral sense
perhaps affords the best and highest distinction between man and
the lower animals ; but I need say nothing on this head, as I
have so lately endeavoured to shew that the social instincts, —
the prime principle of man's moral constitution 5t> — with the aid
of active intellectual powers and the effects of habit, naturally lead
to the golden rule, " As ye would that men should do to you, do
ye to them likewise ;" and this lies at the foundation of morality
•• ' The Thoughts of Marcus Aurelius/ &c, p. 139,
h
EttA*. V, f Intellectual Faculties. 12J
In the next, 'Chapter I shall malie some few remarks on the
probable gieps and means by which the several mental and moral
faculties of man have been gradually evolved. That such evolu-
tion is at least possible, ought not to be denied, for we daily see
these faculties developing in every infant ; and we may trace a
perfect gradation from the mind of an utter idiot, lower than
that of an animal low in the scale, to the mind of a Newton.
CHAPTEE V.
On the Development of the Intellectual and Moral
Faculties during Primeval and Civilised Times.
Advancement of the intellectual powers through natural selection —
Importance of imitation — Social and moral faculties — Their develop-
ment within the limits of the same tribe — Natural selection as affecting
civilised nations — Evidence that civilised nations were once barbarous.
The subjects to be discussed in this chapter are of the highest
interest, but are treated by me in an imperfect and fragmentary
manner. Mr. Wallace, in an admirable paper before referred to, 1
argues that man, after he had partially acquired those intel-
tectual and moral faculties which distinguish him from the
lower animals, would have been but little liable to bodily
modifications through natural selection or any other means.
For man is enabled through his mental faculties " to keep with
" an unchanged body in harmony with the changing universe."
He has great power of adapting his habits to new conditions of
life. He invents weapons, tools, and various stratagems to
procure food and to defend himself. When he migrates into a
colder climate he uses clothes, builds sheds, and makes fires;
and by the aid of fire cooks food otherwise indigestible. He
aids his fellow-men in many ways, and anticipates future events.
Even at a remote period he practised some division of labour.
The lower animals, on the other hand, must have their bodily
structure modified in order to survive under greatly changed
conditions. 'They must be rendered stronger, or acquire more
effective teeth or claws, for defence against new enemies ; or
they must be reduced in size, so as to escape detection and
danger. When they migrate into a colder climate, they must
become clothed with thicker fur, or have their constitutions
altered. If they fail to be thus modified, they will cease to
exist.
^.^ * * Anthropological Review,* May 1864, p. clviii.
[ 28 The Descent of Man} ^ p A at J,
The case, however, is widely different, as ^ Wallace haa
with justice insisted, in relation to the intellectual and moral
faculties of man. These faculties are variable; and we have
every reason to believe that the variations tend to be inherited.
Therefore, if they were formerly of high importance to primeval
man and to his ape-like progenitors, they would have been
perfected or advanced through natural selection. Of the high
importance of the intellectual faculties there can be no doubt,
for man mainly owes to them his predominant position in the
world. We can see, that in the rudest state of society, the
individuals who were the most sagacious, who invented and used
the best weapons or traps, and who were best able to defend
themselves, would rear the greatest number of offspring. The
tribes, which included the largest number of men thus endowed,
would increase in number and supplant other tribes. Numbers
depend primarily on the means of subsistence, and this depends
partly on the physical nature of the country, but in a much higher
degree on the arts which are there practised. As a tribe increases
and is victorious, it is often still further increased by the ab-
sorption of other tribes. 2 The stature and strength of the men
of a tribe are likewise of some importance for its success, and
these depend in part on the nature and amount of the food which
can be obtained. In Europe the men of the Bronze period were
supplanted by a race more powerful, and, judging from their
sword-handles, with larger hands ; s but their success was pro-
bably still more due to their superiority m the arts.
All that we know about savages, or may infer from their
traditions and from, old monuments, the history of which is quite
forgotten by the present inhabitants, shew that from the remotest
times successful tribes have supplanted other tribes. Relics of
extinct or forgotten tribes have been discovered throughout tho
civilised regions of the earth, on the wild plains of America, and
on the isolated islands in the Pacific Ocean. At the present day
civilised nations are everywhere supplanting barbarous nations,
excepting where the climate opposes a deadly barrier ; and they
succeed mainly, though not exclusively, through their arts, which
are the prod ucts of the intellect. It is, therefore, highly probable
that with mankind the intellectual faculties have been mainly
and gradually perfected through natural selection ; and this con-
clusion is sufficient for our purpose. Undoubtedly it would
be interesting to trace the development of each separate faculty
2 After a time the members or 1861, p. 131), that they are the co-
tribes whici are absorbed into descendants of the same ancestor?,
another tribe assume, as Sir Henry 3 Morlot, * Sop. Vaud. Sc. Nat.
Maine remarks ('Ancient Law/ I860, p. 294.
Chap. V. Moral Faculties. 129
from the state in which it exists in the lower animals to that in
which it exists in man; but neither my ability nor knowledge
permits the attempt.
It deserves notice that, as soon as the progenitors of man
became social (and this probably occurred at a very earlyperiod),
the principle of imitation* and reason, and experience would
have increased, and much modified the intellectual powers in a
way, of which we see only traces in the lower animals. Apes are
much given to imitation, as are the lowest savages; and the
simple fact previously referred to, that after a time no animal
can be caught in the same place by the same sort of trap, shews
that animals learn by experience, and imitate the caution of
others. Now, if some one man in a tribe, more sagacious than
the others, invented a new snare or weapon, or other means of
attack or defence, the plainest self-interest, without the assistance
of much reasoning power, would prompt the other members to
imitate him ; and all would thus profit. The habitual practice
of each new art must likewise in some slight degree strengthen
the intellect. If the new invention were an important one, the
tribe would increase in number, spread, and supplant other
tribes. In a tribe thus rendered more numerous there would
always be a rather greater chance of the birth of other superior
and inventive members. If such men left children to inherit
their mental superiority, the chance of the birth of still more
ingenious members would be somewhat better, and in a very
small tribe decidedly better. Even if they left no children, the
tribe would still include their blood- relations ; and it has been
ascertained by agriculturists * that by preserving and breeding
from the family of an animal, which when slaughtered was
found to be valuable, the desired character has been obtained^
Turning now to the social and moral faculties. In order that
primeval men, or the ape-like pregenitors of man, should become
social, they must have acquired the same instinctive feelings,
which impel other animals to live in a body ; and they no doubt
exhibited the same general disposition. They would have felt
uneasy when separated from their comrades, for whom they
would have felt some degree of love; they would have warned
each other of danger, and have given mutual aid in attack or
defence. All this implies some degree of sympathy, fidelity, and
courage. Such social qualities, the paramount importance of
which to the lower animals is disputed by no one, were no doubt
4 1 have given instances in my ' Variation of Animals under Domestica-
tion,* vol. ii. p. 196.
130 The Descent of Man. Part I.
acquired by the progenitors of man in a similar manner, namely,
through natural selection, aided by inherited habit. When two
tribes of primeval man, living in the same country, came into
competition, if (other circumstances being equal) the one tribe
included a great number of courageous, sympathetic and faithful
members, who were always ready to warn each other of danger,
to aid and defend each other, this tribe would succeed better and
conquer the other. Let it be borne in mind how all-important
in the never-ceasing wars of savages, fidelity and courage must
be. The advantage which disciplined soldiers have over undis-
ciplined hordes follows chiefly from the confidence which each
man feels in his comrades. Obedience, as Mr. Bagehot has well
shewn, 5 is of the highest value, for any form of government is
better than none. Selfish and contentious people will not cohere,
and without coherence nothing can be effected. A tribe rich in
the above qualities would spread and be victorious over othei
tribes : but in the course of time it would, judging from all past
history, be in its turn overcome by some other tribe still more
highly endowed. Thus the social and moral qualities would
tend slowly to advance and be diffused throughout the world.
JBut it may be asked, how within the limits of the same tribe
did a large number of members first become endowed with these
social and moral qualities, and how was the standard of ex-
cellence raised ? It is extremely doubtful whether the offspring
of the more sympathetic and benevolent parents, or of those
who were the most faithful to their comrades, would be reared
in greater numbers than the children of selfish and treacherous
parents belonging to the same tribe. He who was ready to
sacrifice his life, as many a savage has been, rather than betray
his comrades, would often leave no offspring to inherit his noble
nature. The bravest men, who were always willing to come to
the front in war, and who freely risked their lives for others,
would on an average perish in larger numbers than other men.
Therefore it hardly seems probable, that the" number of men
gifted with such virtues, or that the standard of their excellence,
could be increased through natural selection, that is, by the
survival of the fittest ; for we are not here speaking of one tribe
being victorious over another.
Although the circumstances, leading to an increase in the
number of those thus endowed within the same tribe, are too
complex to bo clearly followed out, we can trace some of the
probable steps, in the first place, as the reasoning powers and
a See a remarkable series of arti- April 1, 1868 ; July 1, 1869, siac*
clee on ' Physics and Politics ' in the separately published.
• Fortnightly Review." Ko*\ 1 $67 ;
Chap. V. Moral Faculties. 131
foresight of the members became improved, each man would
soon learn that if he aided his fellow-men, he would commonly
receive aid in return. From this low motive he might acquire
the habit of aiding his fellows ; and the habit of performing
benevolent actions certainly strengthens the feeling of sympathy
which gives the first impulse to benevolent actions. Habits,
moreover, followed during many generations probably tend to
be inherited.
But another and much more powerful stimulus to the de-
velopment of the social virtues, is afforded by the praise and the
blame of our fellow-men. To the instinct of sympathy, as we have
already seen, it is primarily due, that we habitually bestow both
praise and blame on others, whilst we love the former and dread
the latter when applied to ourselves; and this instinct no doubt
was originally acquired, like all the other social instincts, through
natural selection. At how early a period the progenitors of man
in the course of their development, became capable of feeling and
being impelled by, the praise or blame of their fellow-creatures,
we cannot of course say. But it appears that even dogs appre-
ciate encouragement, praise, and blame. The rudest savages
feel the sentiment of glory, as they clearly show by preserving
the, trophies of their prowess, by their habit of excessive boasting,
and even by the extreme care which they take of their per-
sonal appearance and decorations ; for unless they regarded the
opinion of their comrades, such habits would be senseless.
They certainly feel shame at the breach of some of their lesser
rules, and apparently remorse, as shewn by the case of the
Australian who grew thin and could not rest from having
delayed to murder some other woman > so as to propitiate his dead
wife's spirit. Though I have not met with any other recorded
case* it is scarcely credible that a savage, who will sacrifice his
life rather than betray his tribe, or one who will deliver himself
up as a prisoner rather than break his parole, 6 would not
feel remorse in his inmost soul, if he had failed in a duty,
which he held sacred.
"We may therefore conclude that primeval man, at a very
remote period, was influenced by the praise and blame of his
fellows. It is obvious, that the members of the same tribe would
approve of conduct which appeared to them to be for the generai
good, and would reprobate that which appeared evil To do
good unto others-feto d6 unto others, as ye would they should do
unto you-^is the ^foundation-stone of morality. It is, therefore,
hardly possible to exaggerate; the importance during rude times
• Mr. Wallace gives cases in of Natural Selection,* 1870, p,
!>i* " CPWViputious to the Theory 354,
K 2
1 32 The Descent of Man, Past L
of the love of praise and the dread of blame. A man who was
not impelled by any deep, instinctive feeling, to sacrifice his
life for the good of others, yet was roused to such actions by a
sense of glory, would by his example excite the same wish for
glory in other men, and would strengthen by exercise the noble
feeling of admiration. He might thus do far more good to his
tribe than by begetting offspring with a tendency to inherit his
own high character.
With increased experience and reason, man perceives the
more remote consequences of his actions, and the self-regarding
virtues, such as temperance, chastity, &c, which during early
times are, as we have before seen, utterly disregarded, come to
be highly esteemed or even held sacred. I need not, however,
repeat what I have said on this head in the fourth chapter.
Ultimately our moral sense or conscience becomes a highly
complex sentiment— originating in the social instincts, largely
guided by the approbation of our fellow-men, ruled by reason,
self-interest, and in later times by deep religious feelings, and
confirmed by instruction and habit.
It must not be forgotten that although a high standard of
morality gives but a slight or no advantage to each individual
man and his children over the other men of the same tribe, yet
that an increase in the number of well-endowed men and an
advancement in the standard of morality will certainly give an
immense advantage to one tribe over another. A tribe including
many members who, from possessing in a high degree the spirit
of patriotism, fidelity, obedience, courage, and sympathy, were
always ready to aid one another, and to sacrifice themselves for
the common good, would be victorious over most other tribes ;
and this would be natural selection. At all times throughout
the world tribes have supplanted other tribes ; and as morality
is one important element in their success, the standard of
morality and the number of well-endowed men will thus every-
where tend to rise and increase.
It is, however, very difficult to form any judgment why one
particular tribe and not another has been successful and has
risen in the scale of civilisation. Many savages are in the same
condition as when first discovered several centuries ago. As Mr.
Bagehot has remarked, we are apt to look at progress as normal
in human society ; but history refutes this. The ancients did
not even entertain the idea, nor do the Oriental nations at the
present day. According to another high authority, Sir Henry
Maine, 7 " the greatest part of mankind has never shewn a
7 'Ancient Law,' 1861, p. 22. nightly Review/ ipril 1, 1868, p.
For Mr. Bagehot's remarks, < Fort 462.
Chap. V. Civilised Nations. 133
u particle of desire that its civil institutions should be im-
" proved." Progress seems to depend on many concurrent
favourable conditions, far too complex to be followed out. But
it has often been remarked, that a cool climate, from leading to
industry and to the various arts, has been highly favourable
thereto. The Esquimaux, pressed by hard necessity, have
succeeded in many ingenious inventions, but their climate has
been too severe for continued progress. Nomadic habits, whether
over wide plains, or through the dense forests of the tropics, or
along the shores of the sea, have in every case been highly
detrimental. Whilst observing the barbarous inhabitants 0!
Tierra del Fuego, it struck me that the possession of some
property, a fixed abode, and the union of many families under a
chief, were the indispensable requisites for civilisation. Such
habits almost necessitate the cultivation of the ground ; and the
first steps in cultivation would probably result, as I have else-
where shewn, 8 from some such accident as the seeds of a fruit-
tree falling on a heap of refuse, and producing an unusually fine
variety. The problem, however, of the first advance of savages
towards civilisation is at present much too difficult to be solved.
Natural Selection as affecting Civilised Nations. — I have hitherto
only considered the advancement of man from a semi-human
condition to that of the modern savage. But some remarks on
the action of natural selection on civilised nations may be worth
adding. This subject has been ably discussed by Mr. W. K.
Greg, 9 and previously by Mr. Wallace and Mr. Gaiton. 10 Most
of my remarks are taken from these three authors. With
savages, the weak in body or mind are soon eliminated ; and
those that survive commonly exhibit a vigorous state of health.
We civilised men, on the other hand, do our utmost to check the
process of elimination ; we build asylums for the imbecile, the
maimed, and the sick ; we institute poor-laws ; and our medical
8 * The Variation of Animals and 1869, and by Mr. E. Ray Lankester
Plants under Domestication/ vol. i, in his * Comparative Longevity/
p. 309. 1870, p. 128. Similar views ap-
• 'Fraser's Magazine/ Sept. 1868, peared previously in the *Austra-
p. 353. This article seems to have lasian/ July 13, 1867. I have
struck many persons, and has given borrowed ideas from several of these
rise to two remarkable essays and a writers.
J-ejoinder in the * Spectator/ Oct. 19 For Mr. Wallace, see * Anthro-
3rd and 17th, 1868. It has also polog. Review/ as before cited. Mr.
been discussed in the ' Q. Journal of Gaiton in * Macmillan's Magazine,'
Science/ 1869, p. 152, and by Mr. Aug. 1865, p. 318 ; also his great
Lawson Tait in the 4 Dublin Q, work, ' Hereditary Genius/ 1870.
/onrnai of Medical Science/ Feb.
134 Tlie Descent of Man. PahtL
men exert their utmost skill to save the life of every one to the
last moment. There is reason to believe that vaccination has
preserved thousands, who from a weak constitution would
formerly have succumbed to small-pox. Thus the weak members
of civilised societies propagate their kind. No one who has
attended to the breeding of domestic animals will doubt that
this must be highly injurious to the race of man. It is surprising
how soon a want of care, or care wrongly directed, leads to the
degeneration of a domestic race ; but excepting in the case of
man himself, hardly any one is so ignorant as to allow his
worst animals to breed.
The aid which we feel impelled to give to the helpless is mainly
an incidental result of the instinct of sympathy, which was
originally acquired as part of the social instincts, but sub-
sequently rendered, in the manner previously indicated, more
tender and more widely diffused. Nor could we check our
sympathy, even at the urging of hard reason, without deteriora-
tion in the noblest part of our nature. The surgeon may harden
himself whilst performing an operation, for he knows that he is
acting for the good of his patient ; but if we were intentionally
to neglect the weak and helpless, it could only be for a* con-
tingent benefit, with an overwhelming present evil. We must
therefore bear the undoubtedly bad effects of the weak surviving
and propagating their kind; but there appears to be at least one
check in steady action, namely that the weaker and inferior
members of society do not marry so freely as the sound; and
this check might be indefinitely increased by the weak in
body or mind refraining from marriage, though this is more to be
hoped for than expected.
In every country in which a large standing army is kept up,
the finest young men are taken by the conscription or are
enlisted. They are thus exposed to early death during war, are
often tempted into vice, and are prevented from marrying during
the prime of life. On the other hand the shorter and feebler men,
with poor constitutions, are left at home, and consequently have
a much better chance of marrying and propagating their kind. 11
Man accumulates property and bequeaths it to his children,
so that the children of the rich have an advantage over the poor
in the race for success, independently of bodily or mental su-
periority. On the other hand, the children of parents who are
short-lived, and are therefore on an average deficient in health
and vigour, come into their property sooner than other children,
11 Prof. H. Fick (' Einfluss der on this head, and on other eucfl
Naturwissenschaft auf das Recht,* porctc.
June, 1872) has some good remarks
Cb ap. Y. Civilised Nations. 1 3 $
and will be likely to marry earlier, and leave a larger number of
offspring to inherit their inferior constitutions. But the in-
heritance of property by itself is very far from an evil ; for
without the accumulation of capital the arts cculd not progress;
and it is chiefly through their power that the civilised races have
extended, and are now everywhere extending their range, so as
to take the place of the lower races. Nor does the moderate
accumulation of wealth interfere with the process of selection.
When a poor man becomes moderately rich,, his children enter
trades or .professions in which there is struggle enough, so that
the able in body and mind succeed best. The presence of a body
of well-instructed men, who have not to labour for their daily
bread, is important to a degree which cannot be over-estimated ;
as all high intellectual work is carried on by them, and on such
work, material progress of all kinds mainly depends, not to
mention other and higher advantages. No doubt wealth when
very great tends to convert men into useless drones, but their
number is never large ; and some degree of elimination here
occurs, for we daily see rich men, who happen to be fools or
profligate, squandering away their wealth.
Primogeniture with entailed estates is a more direct evil,
though it may formerly have been a great advantage by the
creation of a dominant class, and any government is better
than none. Most eldest sons, though they may be weak in body
or mind, marry, whilst the younger sons, however superior
in these respects, do not so generally marry. Nor can worth-
less eldest sons with entailed estates squander their wealth.
But here, as elsewhere, the relations of civilised life are so
complex that some compensatory checks intervene. The men
who are rich through primogeniture are able to select genera-
tion after generation the more beautiful and charming women ;
and these must generally be healthy in body and active in
mind. The evil consequences, such as they may be, of the
continued preservation of the same line of descent, without any
selection, are checked by men of rank always wishing to increase
their wealth and power; and this they effect by marrying
heiresses. But the daughters of parents who have produced
single children, are themselves, as Mr. Oalton has shewn, apt to
be sterile ; and thus noble families are continually cut off in the
direct line, and their wealth flows into some side channel; but
unfortunately this channel is not determined by superiority of
any kind.
Although civilisation thus checks in many ways the action of
12 * Hereditary Greaius ' 1870, pp. 132-140.
136 The Descent of Man. Part L
natural selection, it apparently favours the better development
of the body, by means of good food and the freedom from occa-
sional hardships. This may be inferred from civilised men
having been found, wherever compared, to be physically
stronger than savages. 13 They appear also to have equal powers
of endurance, as has been proved in many adventurous ex-
peditions. Even the great luxury of the rich can be but little
detrimental ; for the expectation of life of our aristocracy, at all
ages and of both sexes, is very little inferior to that of healthy
English lives in the lower classes. 14
We will now look to the intellectual faculties. If in eacli
grade of society the members were divided into two equal
bodies, the one including the intellectually superior and the
other the inferior, there can be little doubt that the former
would succeed best in all occupations, and rear a greater number
of children. Even in the lowest walks of life, skill and ability
must be of some advantage; though in many occupations,
owing to the great division of labour, a very small one. Hence
in civilised nations there will be some tendency to an increase
both in the number and in the standard of the intellectually
able. But I do not wish to assert that this tendency may not be
more than counterbalanced in other ways, as by the multiplica-
tion of the reckless and improvident ; but even to such as these,
ability must be some advantage.
It has often been objected to views like the foregoing, that the
most eminent men who have ever lived have left no offspring to
inherit their great intellect. Mr. Galton says, 15 " I regret I am
" unable to solve the simple question whether, and bow far,
t{ men and women who are prodigies of genius are infertile. I
'* have, however, shewn that men of eminence are by no means
' so." Great lawgivers, the founders of beneficent religions,
<*reat philosophers and discoverers in science, aid the progress of
mankind in a far higher degree by their works than by leaving
a numerous progeny. In the case of corporeal structures, it is
the selection of the slightly better-endowed and the elimination
of the slightly less well-endowed individuals, and not the pre-
servation of strongly-marked and rare anomalies, that leads to
the advancement of a species. 16 So it will be with the intellectual
faculties, since the somewhat abler men in each grade of society
13 Quatrefages, * Revue des Cours 1870, p. 115.
Scientifiques/ 1867-68, p. 659. >* * Hereditary Genius/ 1870, p.
14 See the fifth and sixth columns, 330.
compiled from good authorities, in " ' Origin of Species ' (fifth eii«
the table given in Mr. E. R. Lan- tion, 1869), p. 104.
kester's * Comparative Longevity
Chap. V. Civilised Nations. 1 37
succeed rather better than the less able, and consequently
increase in number, if not otherwise prevented. When in
any nation the standard of intellect and the number of intel-
lectual men have increased, we may expect from the law of
the deviation from an average, that prodigies of genius will, as
shewn by Mr. Galton, appear somewhat more frequently than
before.
In regard to the moral qualities, some elimination of the
worst dispositions is always in progress even in the most civilised
nations. Malefactors are executed, or imprisoned for long
periods, so that they cannot freely transmit their bad qualities.
Melancholic and insane persons are confined, or commit suicide.
Violent and quarrelsome men often come to a bloody end. The
restless who will not follow any steady occupation — and this
relic of barbarism is a great check to civilisation 17 — emigrate to
newly-settled countries, where they prove useful pioneers. In-
temperance is so highly destructive, that the expectation of life
of the intemperate, at the age of thirty for instance, is only 13*8
years ; whilst for the rural labourers of England at the same age
it is 40*59 years. 18 Profligate women bear few children, and
profligate men rarely marry ; both suffer from disease. In the
breeding of domestic animals, the elimination of those individuals*
though few in number, which are in any marked manner inferior,
is by no means an unimportant element towards success. This
especially holds good with injurious characters which tend tc
reappear through reversion, such as blackness in sheep; and
with mankind some of the worst dispositions, which occasionally
without any assignable cause make their appearance in families,
may perhaps be reversions to a savage state, from which we are
not removed by very many generations. This view seems
indeed recognised in the common expression that such men are
the black sheep of the family.
With civilised nations, as far as an advanced standard of
morality, and an increased number of fairly good men are con-
cerned, natural selection apparently effects but little ; though
the fundamental social instincts were originally thus gained.
But I have already said enough, whilst treating of the lower
races, on the causes which lead to the advance of morality,
namely, the approbation of our fellow-men — the strengthening
17 * Hereditary Genius,' 1870, p. Neison's * Vital Statistics.' In re-
34-7. gard to profligacy, see Dr. Fair,
lf E. Ray Lankester, * Compara- * Influence of Marriage on Mor*
tive Longevity/ 1570, p. 115. The tality/ * Nat. Assoc, for the Promo*
table of the intemperate is from tion of Social Science/ IS'jS.
138 The Descent of Man. i>art I.
of our sympathies by habit— example and imitation — reason —
experience, and even self-interest — instruction during youth, and
religious feelings.
A most important obstacle in civilised countries to an increase
in the number of men of a superior class has been strongly insisted
un by Mr. Greg and Mr. Galton, 19 namely, the fact that the very
poor and reckless, who are often degraded by vice, almost invari-
ably marry early, whilst the careful and frugal, who are generally
ccherwise virtuous, marry late in life, so that they may be able
co support themselves and their children in comfort. Those who
marry early produce within a given period not only a greater
number of generations, but, as shewn by Dr. Duncan, 20 they pro-
duce many more children. The children, moreover, that are
born by mothers during the prime of life are heavier and larger,
and therefore probably more vigorous, than those born at other
periods. Thus the reckless, degraded, and often vicious members
of society, tend to increase at a quicker rate than the provident
and generally virtuous members. Or as Mr. Greg puts the case :
" The careless, squalid, unaspiring Irishman multiplies like
"rabbits: the frugal, foreseeing, self-respecting, ambitious Scot,
"stern in his morality, spiritual in his faith, sagacious and dis-
" ciplined in his intelligence, passes his best years in struggle
"and in celibacy, marries late, and leaves few behind him.
" Given a land originally peopled by a thousand Saxons and a
* thousand Celts — and in a dozen generations five-sixths of the
^population would be Celts, but five-sixths of the property, of
" the power, of the intellect, would belong to the one-sixth of
" Saxons that remained. In the eternal ' struggle for existence/
" it would be the inferior and less favoured race that had pre-
" vailed — and prevailed by virtue not of its good qualities but of
-its faults."
There are, however, some checks to this downward tendency.
We have seen that the intemperate suffer from a high rate of
mortality, and the extremely profligate leave few offspring. The
poorest classes crowd into towns, and it has been proved by Dr.
Stark from the statistics of ten years in Scotland, 21 that at all
19 ' Fraser*s Magazine,* Sept. title of ' Fecundity, Fertility, and
1868, p. 353. 'Macmillan's Maga- Sterility,* 1871. See, also, Mr
zine, Aug. 1865, p. 318. The Rev. Galton, * Hereditary Genius/ pp.
F. W. Farrar (' Fraser*s Mag.* Aug. 35L ^357, for observations to the
1870, p. 264) takes a different view, above effect.
96 « On the Laws of the Fertility 21 * Tenth Annual Report 01
of Women,' in * Transact. Royal Births, Deaths, &c, id Scotland,
Soc.' Edinburgh, vol. xxiv. p. 287; 1867, p, xxix.
»ow published separately under the
Chap. V. Civilised Nations. 1 39
ages the death-rate is higher in towns than in rural districts,
'' &nd during the first five years of life the town death-rate ia
"almost exactly double that of the rural districts." As these re-
turns include both the rich and the poor, no doubt more than
twice the number of births would be requisite to keep up the
number of the very poor inhabitants in the towns, relatively to
those in the country. With women, marriage at too early an
age is highly injurious ; for it has been found in France that,
" twice as many wives under twenty die in the year, as died out
" of the same number of the unmarried." The mortality, also,
of husbands under twenty is "excessively high," 22 but what the
cause of this may be, seems doubtful. Lastly, if the men who
prudently delay marrying until they can bring up their families
in comfort, were to select, as they often do, women in the prime
of life, the rate of increase in the better class would be only
slightly lessened.
It was established from an enormous body of statistics, taken
during 1853, that the unmarried men throughout France,
between the ages of twenty and eighty, die in a much larger
proportion than the married : for instance, out of every 1000
unmarried men, between the ages of twenty and thirty, 11*3
annually died, whilst of the married only 65 died. 23 A similar
law was proved to hold good, during the years 1863 and 1864,
with the entire population above the age of twenty in Scotland :
for instance, out of every 1000 unmarried men, between the ages
of twenty and thirty, 14*97 annually died, Whilst of the married
only 7*24 died, that is less than half. 24 Dr. Stark remarks on
this, " Bachelorhood is more destructive to life than the most
" unwholesome trades, or than residence in an unwholesome
"house or district where there has never been the most distant
"attempt at sanitary improvement." He considers that the
lessened mortality is the direct result of "marriage, and the
"more regular domestic habits which attend that state." He
admits, however, that the intemperate, profligate, and criminal
classes, whose duration of life is low, do not commonly marry ;
and it must likewise be admitted that men with a weak constitu-
** These quotations are taken from the same striking paper,
from our highest authority on such 24 I have taken the mean of the
questions, namely, Dr. Farr, in his quinquennial means, given in 'The
paper <0n the Influence of Mar- Tenth Annual Report of Births,
riage on the Mortality of the French Deaths, &c, in Scotland/ 1867.
People/ read before the Nat. Assoc. The quotation from Dr. Stark is
for the Promotion cf Social Science* copied from an article in the * Daily
1858. , News/ Oct. 17th, Ig68, which Dr,
28 Dr. Farr, ibid. The quota- Farr considers very carefilly wriV
iions given below are extracted ten.
140 Tlie Descent of Man. Part I,
tion, ill health, or any great infirmity in body or mind, will often
not wish to marry, or will be rejected. Dr. Stark seems to have
come to the conclusion that marriage in itself is a main cause of
prolonged life, from finding that aged married men still have a
considerable advantage in this respect over the unmarried of the
same advanced age ; but every one must have known instances
of men, who with weak health during youth did not marry, and
yet have survived to old age, though remaining weak, and there-
fore always with a lessened chance of life or of marrying. There
is another remarkable circumstance which seems to support Dr.
Stark's conclusion, namely, that widows and widowers in France
suffer in comparison with the married a very heavy rate of mor-
tality ; but Dr. Farr attributes this to the poverty and evil habits
consequent on the disruption of the family, and to grief. On
the whole we may conclude with Dr. Farr that the lesser mortality
of married than of unmarried men, which seems to be a general
law, "is mainly due to the constant elimination of imperfect
*' types, and to the skilful selection of the finest individuals out
" of each successive generation ;" the selection relating only to
the marriage state, and acting on all corporeal, intellectual, and
moral qualities. 25 We may, therefore, infer that sound and
good men who out of prudence remain for a time unmarried, do
not suffer a high rate of mortality.
If the various checks specified in the two last paragraphs, and
perhaps others as yet unknown, do not prevent the reckless, the
vicious and otherwise inferior members of society from increas-
ing at a quicker rate than the better class of men, the nation will
retrograde, as has too often occurred in the history of the world.
We must remember that progress is no invariable rule. It is
yery difficult to say why one civilised nation rises, becomes more
powerful, and spreads more widely, than another; or why the
same nation progresses more quickly at one time than at another.
We can only say that it depends on an increase in the actual
number of the population, on the number of the men endowed
with high intellectual and moral faculties, as well as on their
standard of excellence. Corporeal structure appears to have
little influence, except so far as vigour of body leads to vigour of
mind.
It has been urged by several writers that as high intellectual
powers are advantageous to a nation, the old Greeks, who stood
some grades higher in intellect than any race that has ever
• 5 Dr. Duncan remarks (' Fecund- " from the unmarried side to th<
ity, Fertility/ &c, 1871, p. 334) on " married, leaving the unmarried
this subject; "At every age the "columns crowded with the sickly
, w healthy and beautiful go over " and unfortunate/'
Cha? V. Civilised Nations. 141
existed, 26 ought, if the power of natural selection were real, to
have risen still higher in the scale, increased in number, and
stocked the whole of Europe. Here we have the tacit assump-
tion, so often made with respect to corporeal structures, that
there is some innate tendency towards continued development in
mind and body. But development of all kinds depends on many
concurrent favourable circumstances. Natural selection acts
only tentatively. Individuals and races may have acquired cer-
tain indisputable advantages, and yet have perished from failing
in other characters. The Greeks may have retrograded from a
want of coherence between the many small states, from the small
size of their whole country, from the practice of slavery, or from
extreme sensuality ; for they did not succumb until ** they were
" enervated and corrupt to the very core." 27 The western nations
of Europe, who now so immeasurably surpass their former savage
progenitors, and stand at the summit of civilisation, owe little
or none of their superiority to direct inheritance from the old
Greeks, though they owe much to the written works of that
wonderful people.
Who can positively say why the Spanish nation, so dominant
at one time, has been distanced in the race. The awakening of
the nations of Europe from the dark ages is a still more perplex-
ing problem. At that early period, as Mr. Galton has remarked,
almost all the men of a gentle nature, those given to meditation
or culture of the mind, had no refuge except in the bosom of
a Church which demanded celibacy; 28 and this could hardly
fail to have had a deteriorating influence on each successive
generation. During this same period the Holy Inquisition
selected with extreme care the freest and boldest men in order
to burn or imprison them. In Spain alone some of the best
men — those who doubted and questioned, and without doubting
there can be no progress — were eliminated during three cen-
turies at the rate of a thousand a year. The evil which the
Catholic Church has thus effected is incalculable, though no
dczbt counterbalanced to a certain, perhaps to a large, extent
in other ways ; nevertheless, Europe has progressed at an un-
paralleled rate.
*• See the ingenious and original 257) advances arguments on the
argument on this subject by Mr. other side. Sir C. Lyell had already
Galton, * Hereditary Genius,' pp. (' Principles of Geology,' vol. u.
340-342. 1868, p. 489) in a striking passage
27 Mr. Greg, * Eraser's Magazine,' called attention to the evil influence
Sept. 1868, p. 357. of the Holy Inquisition in having,
*• ' Hereditary Genius,* 1870, pp. through selection, lowered the gene-
357-359. The Rev. F. W. Farrar ral standard of intelligence in £u-
('Fraser's Mag.,' Aug. 1870, p. rope.
142 Tlie Descent of Man. Paet I.
The remarkable success of the English as colonists, compared
toother European nations, has been ascribed to their "daring
" and persistent energy ; " a result which is well illustrated by
comparing the progress of the Canadians of English and French
extraction ; but who can say how the English gained their energy ?
There is apparently much truth in the belief that the wonderful
progress of the United States, as well as the character of the
people, are the results of natural selection ; for the more ener-
getic, restless, and courageous men from all parts of Europe
have emigrated during the last ten or twelve generations to that
great country, and have there succeeded best. 29 Looking to the
distant future, I do not think that the Eev. Mr. Zincke takes an
exaggerated view when he says I s0 " All other series of events —
" as that which resulted in the culture of mind in Greece, and
"that which resulted in the empire of Eome— only appear to
" have purpose and value when viewed in connection with, or
" rather as subsidiary to .... the great stream of Anglo-Saxon
" emigration to the west." Obscure as is the problem of the
advance of civilisation, we can at least see that a nation
which produced during a lengthened period the greatest
number of highly intellectual, energetic, brave, patriotic, and
benevolent men, would generally prevail over less favoured
nations.
Natural selection follows from the struggle for existence ; and
this from a rapid rate of increase. It is impossible not to regret
bitterly, but whether wisely is another question, the rate at
which man tends to increase ; for this leads in barbarous tribes
to infanticide and many other evils, and in civilised nations to
abject poverty, celibacy, and to the late marriages of the prudent.
But as man suffers from the same physical evils as the lower
animals, he has no right to expect an immunity from the evils
consequent on the struggle for existence. Had he not been sub-
jected during primeval times to natural selection, assuredly he
would never have attained to his present rank. Since we see in
many parts of the world enormous areas of the most fertile land
capable of supporting numerous happy homes, but peopled only
by a few wandering savages, it might be argued that the struggle
for existence had not been sufficiently severe to force man up-
wards to his highest standard. Judging from all that we know
of man and the lower animals, there has always been sufficient
variability in their intellectual and moral faculties, for a steady
advance through natural selection. No doubt such advance
** Mr. Gaiton, < Macmillan's and National Life/ Dec. 1869, p. 184.
Magazine,' August, 1865, p. 325. 30 'Last. Winter in the United
See also, ' Nature,* « On Darwinism States,' 1868, p. 29.
Ohap.T. Civilised Nations. 143
demands many favourable concurrent circumstances; but it may
well be doubted whether the most favourable would have sufficed,
had not the rate of increase been rapid, and the consequent
struggle for existence extremely severe. It even appears from
what we see, for instance, in parts of S. America, that a people
which may be called civilised, such as the Spanish settlers, is
liable to become indolent and to retrograde, when the con-
ditions of life are very easy. With highly civilised nations con-
tinued progress depends in a subordinate degree on natural
selection ; for such nations do not supplant and exterminate one
another as do savage tribes. Nevertheless the more intelligent
members within the same community will succeed better in the
long run than the inferior, and leave a more numerous progeny,
and this is a form of natural selection. The more efficient
causes of progress seem to consist of a good education during
youth whilst the brain is impressible, and of a high standard of
excellence, inculcated by the ablest and best men, embodied in
the laws, customs and traditions of the nation, and enforced by
public opinion. It should, however, be borne in mind, that the
enforcement of public opinion depends on our appreciation of
the approbation and disapprobation of others ; and this apprecia-
tion is founded on our sympathy, which it can hardly be doubted
was originally developed through natural selection as one of the
most important elements of the social instincts. 81
On the evidence that all civilised nations were once barbarous.—
The present subject has been treated in so full and admirable a
manner by Sir J. Lubbock, 32 Mr. Tylor, Mr. M'JLennan, and
others, that I need here give only the briefest summary of their
results. The arguments recently advanced by the Duke of
Argyll 33 and formerly by Archbishop Whately, in favour of the
belief that man came into the world as a civilised being, and
that all savages have since undergone degradation, seem to me
weak in comparison with those advanced on the other side.
Many nations, no doubt, have fallen away in civilisation, and
some may have lapsed into utter barbarism, though on this
latter head I have met with no evidence. The Fuegians were
probably compelled by other conquering hordes to settle in their
inhospitable country, and they may have become in consequence
somewhat more degraded; but it would be difficult to prove
**' I am much indebted to Mr. 8a ' On the Origin of Civilisation/
John Morley for some good criti- *Proc. Ethnological Soc.* Nov, 26
eisms on this subject: see, also, 1867.
Broca, *Les Selections/ * Revue d'An- ■» ' Primeval Man/ 1869.
fcbropologie/ 1872.
144 The Descent of Man. Pabt L
that they have fallen much below the Botocudos, who inhabit
fche finest parts of Brazil.
The evidence that all civilised nations are the descendants of
barbarians, consists, on the one side, of clear traces of theii
former low condition in still-existing customs, beliefs, language,
&c. ; and on the other side, of proofs that savages are inde-
pendently able to raise themselves a few steps in the scale of
civilisation, and have actually thus risen. The evidence on the
first head is extremely curious, but cannot be here given : I refer
to such cases as that of the art of enumeration, which, as Mr.
Tylor clearly shews by reference to the words still used in some
places, originated in counting the fingers, first of one hand and
then of the other, and lastly of the toes. We have traces of this
in our own decimal system, and in the Roman numerals, where,
after the V., which is supposed to be an abbreviated picture of a
human hand, we pass on to VI., &c, when the other hand no
doubt was used. So again, " when we speak of three-score and
" ten, we are counting by the vigesimal system, each score thus
" ideally made, standing for 20 — for ' one man ' as a Mexican or
" Carib would put it." 34 According to a large and increasing
school of philologists, every language bears the marks of its slow
and gradual evolution. So it is with the art of writing, for
letters are rudiments of pictorial representations. It is hardly
possible to read Mr. M'Lennan's work 85 and not admit that
almost all civilised nations still retain traces of such rude habits
as the forcible capture of wives. What ancient nation, as the
same author asks, can be named that was originally mono-
gamous? The primitive idea of justice, as shewn by the law of
battle and other customs of which vestiges still remain, was
likewise most rude. Many existing superstitions are the
remnants of former false religious beliefs. The highest form of
religion — the grand idea of God hating sin and loving right-
eousness — was unknown during primeval times.
Turning to the other kind of evidence : Sir J. Lubbock has
shewn that some savages have recently improved a little in
some of their simpler arts. From the extremely curious
account which he gives of the weapons, tools, and arts, in use
** 'Royal Institution of Great 'A Conjectural Solution of the
Britain,' March 15, 1867. Also, Origin of the Class, System of
* Researches into the Early History Relationship/ in ' Proc. American
of Mankind,' 1865. Acad, of Sciences/ vol. vii. Feb.
•* 'Primitive Marriage/ 1865. 1868. Prof. Schaaffhausen ('An-
3ee, likewise, an excellent article, thropolog. Review/ Oct. 1869, p.
evidently by the same author, in 373) remarks on "the vestiges of
the ' North British Review/ July, " human sacrifices found both io
1869. Also, Mr. L. H. Morgan, " Homer and the Old Testament."
Chap. V, Nations. 145
amongst savages in various parts of the world, it cannot bo
doubted that these have nearly all been independent discoveries,
excepting perhaps the art of making fire. 36 The Australian
boomerang is a good instance of one such independent discovery.
The Tahitians when first visited had advanced in many respects
beyond the inhabitants of most of the other Polynesian islands.
There are no just grounds for the belief that the high culture of
the native Peruvians and Mexicans was derived from abroad ;"
many native plants were there cultivated, and a few native
animals domesticated. We should bear in mind that, judging
from the small influence of most missionaries, a wandering crew
from some senii-civilised land, if washed to the shores of
America, would not have produced any marked effect on the
natives, unless they had already become somewhat advanced.
Looking to a very remote period in the history of the world, wo
find, to use Sir J. Lubbock's well-known terms, a paleolithic and
neolithic period ; and no one will pretend that the art of
grinding rough flint tools was a borrowed one. In all parts of
Europe, as far east as Greece, in Palestine, India, Japan, New
Zealand, and Africa, including Egypt, flint tools have been
discovered in abundance; and of their use the existing in-
habitants retain no tradition. There is also indirect evidence of
their former use by the Chinese and ancient Jews. Hence there
can hardly be a doubt that the inhabitants of these countries,
which include nearly the whole civilised world, were once
in a barbarous condition. To believe that man was abori-
ginally civilised and then suffered utter degradation in so many
regions, is to take a pitiably low view of human nature. It is
apparently a truer and more cheerful view that progress nas
been much more general than retrogression; that man has risen,
though by slow and interrupted steps, from a lowly condition to
the highest standard as yet attained by him in knowledge,
morals and religion.
8a Sir J. Lubbock, « Prehistoric edit., 1870.
Times/ 2nd edit. 1869, chap. xv. » Dr. F. Miiller has made som*
and xvi. et passim. See also the good remarks to this eflect in th«
excellent 9th c\apter in Trior's * Reise der Novara : Anthropo^og
* Early History »f Mankind,* 2nd Theil/ Abthei 1 iii. 1868 s. 127.
145 The Descent of Man. r Afct 1
CHAPTER VL
On the Affinities and Genealogy of Man.
Petition of man in the animal series — The natural system genealogical—*
Adaptive characters of slight value — Various small points of rescm-
" blance between man and the Quadrumana — Rank of man in the natural
system — Birthplace and antiquity of man — Absence of fossil connecting-
links* — Lower stages in the genealogy of man, as inferred, firstly from
his affinities and secondly from his structure — Early androgynous con-
dition of the Vertebrata — Conclusion.
Even if it be granted that the difference between man and his
nearest allies is as great in corporeal structure as some natu-
ralists maintain, and although we must grant that the differ-
ence between them is immense in mental power, yet the facts
given in the earlier chapters appear to declare, in the plainest
manner, that man is descended from some lower form, notwith-
standing that connecting-links have not hitherto been dis-
covered.
Man is liable to numerous, slight, and diversified variations,
which are induced by the same general causes, are governed
and transmitted in accordance with the same general laws, as in
the lower animals. Man has multiplied so rapidly, that he has
necessarily been exposed to struggle for existence, and con-
sequently to natural selection. He has given rise to many races,
some of which differ so much from each other, that they have
often been ranked by naturalists as distinct species. His body
is constructed on the same homological plan as that of other
mammals. He passes through the same phases of embryo-
logical development. He retains many rudimentary and useless
structures, which no doubt were once serviceable. Characters
occasionally make their re-appearance in him, which we have
reason to believe were possessed by his early progenitors. If the
origin of man had been wholly different from that of all other
animals, these various appearances would be mere empty
deceptions ; but such an admission is incredible. These appear-
ances, on the other hand, are intelligible, at least to a large
extent, if man is the co-descendant with other mammals of some
unknown and lower form.
Some naturalists, from being deeply impressed with tho
mental and spiritual powers of man, have divided the whole
areradc world into three kingdoms, the Human, the Animal,
Chap. VI. Affinities and Genealogy. *47
and the Vegetable, thus giving to man a separate kingdom. 1
Spiritual powers cannot be compared or classed by the natu-
ralist : but he may endeavour to shew, as I have done, that the
mental faculties of man and the lower animals do not differ in
kind, although immensely in degree. A difference in degree, .
however great, does not justify us in placing man in a distinct
kingdom, as will perhaps be best illustrated by comparing the
mental powers of two insects, namely, a coccus or scale-insect
and an ant, which undoubtedly belong to the same class. The
difference is here greater than, though of a somewhat different kind
from, that between man and the highest mammal. The female
coccus, whilst young, attaches itself by its proboscis to a plant ;
sucks the sap, but never moves again; is fertilised and lays eggs;
and this is its whole history. On the other hand, to describe the
habits and mental powers of worker-ants, would require, as
Pierre Huber has shewn, a large volume ; I may, however, briefly
specify a few points. Ants certainly communicate information to
each other, and several unite for the same work, or for games of
play. They recognise their fellow-ants after months of absence,
and feel sympathy for each other. They build great edifices,
keep them clean, close the doors in the evening, and post
sentries. They make roads as well as tunnels under rivers, and
temporary bridges over them, by clinging together. They
collect food for the community, and when an object, too large for
entrance, is brought to the nest, they enlarge the door, and
afterwards build it up again. They store up seeds, of which
they prevent the germination, and which, if damp, are brought
up to the surface to dry. They keep aphides and other insects as
milch-cows. They go out to battle in regular bands, and freely
sacrifice their lives for the common weal. They emigrate ac-
cording to a preconcerted plan. They capture slaves. They move
the eggs of their aphides, as well as their own eggs and cocoons,
into warm parts of the nest, in order that they may be quickly
hatched ; and endless similar facts could be given. 3 On the
whole, the difference in mental power between an ant and a
coccus is immense ; yet no one has ever dreamed of plying these
insects in distinct classes, much less in distinct kingdoms. No
1 Isidore Geoffroy St.-Hilaire gives of ants are given by Mr. Belt, in
a detailed account of the position in his * Naturalist, in Nicaragua/
assigned to man by various natural- 1874. See also Mr. Moggridge's
ists in their classifications: <Hst. admirable work, < Harvesting Ants/
Nat. Gen/ torn. ii. 1859, pp. 1?0- &c., 1873, also *L'Instinct chez les
189. Insectes/ by M. George Pouchet,
2 Some of the most interesting * Revue des Deux Mondes/ Feb
fac*s ev«r published on the habits 1870 p. 682.
148 The Descent of Man. Part I.
doubt the difference is bridged over by other insects ; and this
is not the case with man and the higher apes. But we have
every reason to believe that the breaks in the series are simply
the results of many forms having become extinct.
Professor Owen, relying chiefly on the structure of the brain,
has divided the mammalian series into four sub-classes. One of
these he devotes to man; in another he places both the
Marsupials and the Monotremata; so that he makes man as
distinct from all other mammals as are these two latter groups
conjoined. This view has not been accepted, as far as I am
aware, by any naturalist capable of forming an independent
judgment, and therefore need not here be further considered.
We can understand why a classification founded on any single
character or organ — even an organ so wonderfully complex and
important as the brain — or on the high development of the
mental faculties, is almost sure to prove unsatisfactory. This
principle has indeed been tried with hymenopterous insects;
but when thus classed by their habits or instiDcts, the arrange-
ment proved thoroughly artificial. 3 Classifications may, of
course, be based on any character whatever, as on size, colour,
or the element inhabited; but naturalists have long felt a
profound conviction that there is a natural system. This
system, it is now generally admitted, must be, as far as possible,
genealogical in arrangement, — that is the co-descendants of the
same form must be kept together in one group, apart from the
co-descendants of any other form ; but if the parent-forms are
related, so will be their descendants, and the two groups to-
gether will form a larger group. The amount of difference
between the several groups — that is the amount of modification
which each has undergone — is expressed by such terms as
genera, families, orders, and classes. As we have no record of
the lines of descent, the pedigree can be discovered only by
observing the degrees of resemblance between the beings which
are to be classed. For this object numerous points of resem-
blance are of much more importance than the amount of
similarity or dissimilarity in a few points. If two languages
were found to resemble each other in a multitude of words and
points of construction, they would be universally recognised as
having sprung from a common source, notwithstanding that
they differed greatly in some few words or points of construction.
But with organic beings the points of resemblance must not
consist of adaptations to similar habits of life : two animals may,
tor instance, have had their whole frames modified for living in
f West wool '• aVde?jD Oas* of Jnsecu/ y©L " 1840, p. 87
Chap. VI. Affinities and Genealogy, 149
the water, and yet they will not be brought any nearer to each
other in the natural system. Hence we can see how ifc is that
-esemblances in several unimportant structures, in useless and
rudimentary organs, or not now functionally active, or in an
embryological condition, are by far the most serviceable for clas-
sification ; for they can hardly be due to adaptations within a
late period ; and thus they reveal the old lines of descent or of
true affinity.
We can further see why a groat amount of modification in
some one character ought not to lead us to separate widely any
two organisms. A part which already differs much from the
same part in other allied forms has already, according to the
theory of evolution, varied much; consequently it would (as long
as the organism remained exposed to the same exciting con-
ditions) be liable to further variations of the same kind ; and
these, if beneficial, would be preserved, and thus be continually
augmented. In many cases the continued development of a part,
for instance, of the beak of a bird, or of the teeth of a mammal,
would not aid the species in gaining its food, or for any other
object ; but with man we can see no definite limit to the con-
tinued development of the brain and mental faculties, as far as
advantage is concerned. Therefore in determining the position
of man in the natural or genealogical system, the extreme de-
velopment of his brain ought not to outweigh a multitude of
resemblances in other less important or quite unimportant
points.
The greater number of naturalists who have taken into con-
sideration the whole structure of man, including his mental
faculties, have followed Blumenbach and Cuvier, and have placed
man in a separate Order, under the title of the Bimana, and
therefore on an equality with the orders of the Quadrumana,
Carnivora, &c. Eecently many of our best naturalists have
recurred to the view first propounded by Linnaeus, so remarkable
for his sagacity, and have placed man in the. same Order with
the Quadrumana, under the title of the Primates. The justice of
this conclusion will be admitted : for in the first place, we must
bear in mind the comparative insignificance for classification
of the great development of the brain in man, and that the
strongly-marked differences between the skulls of man and the
Quadrumana (lately insisted upon by Bischoff, Aeby, and others v
apparently follow from their differently developed brains. In
the second place, we must remember that nearly all the other
and more important differences between man and the Quadrumana
are manifestly adaptive in their nature, and relate chiefly to the
erect position of man ; such as the structure of his hand, foot,
1 50 The Descent of Mam Part L
and palvis, the curvature of his spine, and the position of his
head. The family of Seals offers a good illustration of the small
importance of adaptive characters for classification. These
animals differ from all other Carnivora in the form of their
bodies and in the structure of their limbs, far more than does
man from the higher apes; yet in most systems, from that of
Cuvier to the most recent one by Mr. Flower, 4 seals are ranked
as a mere family in the Order of the Carnivora. If man had not
been his own classifier, he would never have thought of founding
a separate order for his own reception.
It would be beyond my limits, and quite beyond my knowledge,
even to name the innumerable points of structure in which man
agrees with the other Primates. Our great anatomist and
philosopher, Prof. Huxley, has fully discussed this subject, 6 and
concludes that man in all parts of his organisation differs less
from the higher apes, than these do from the lower members of
the same group. Consequently there "is no justification for
" placing man in a distinct order."
In an early part of this work I brought forward various
facts, shewing how closely man agrees in constitution with the
higher mammals; and this agreement must depend on our
close similarity in minute structure and chemical composition.
I gave, as instances, our liability to the same diseases, and to the
attacks of allied parasites; our tastes in common for the same
stimulants, and the similar effects produced by them, as well as
by various drugs, and other such facts.
As small unimportant points of resemblance between man and
the Quadrumana are not commonly noticed in systematic works,
and as, when numerous, they clearly reveal our relationship, I
will specify a few such points. The relative position of our
features is manifestly the same ; and the various emotions are
displayed by nearly similar movements of the muscles and skin,
chiefly above the eyebrows and round the mouth. Some few
expressions are, indeed, almost the same, as in the weeping of
certain kinds of monkeys and in the laughing noise made by
others, during which the corners of the mouth are drawn back-
wards, and the lower eyelids wrinkled. The external ears are
curiously alike. In man the nose is much more prominent than
in most monkeys ; but we may trace the commencement of an
aquiline curvature in the nose of the Hoolock Gibbon ; and this
in the Semnopithecus nasica is carried to a ridiculous extreme.
The faces of many monkeys are ornamented with beards,
whiskers, or moustaches. The hair on the head grows to a great
4 'Proc. Zoolog. Soc/ 1863, p. 4.
* « Evidence as to Man's Place in Nature,' 1863, p. 70, et passtm.
Chap. VL Affinities and Genealogy. 15 1
length in some species of Semnopithecus; 5 and in the Bonnet
monkey (Macacus radiatus) it radiates from a point on the crown s
with a parting down the middle. It is commonly said that the
forehead gives to man his noble and intellectual appearance ; bat
the thick hair on the head of the Bonnet monkey terminates
downwards abruptly, and is succeeded by hair so short and fine
that at a little distance the forehead, with the exception of the
eyebrows, appears quite naked. It has been erroneously asserted
that eyebrows are not present in any monkey. In the species
just named the degree of nakedness of the forehead differs in
different individuals; and Eschricht states 7 that in our children
the limit between the hairy scalp and the naked forehead is
sometimes not well defined; so that here we seem to have a
trifling case of reversion to a progenitor, in whom the forehead
had not as yet become quite naked.
It is well known that the hair on our arms tends to converge
from above and below to a point at. the elbow. This curious
arrangement, so unlike that in most of the lower mammals, is
common to the gorilla, chimpanzee, orang, some species oi
Hylobates, and even to some few American monkeys. But in
Eylobates agilis the hair on the fore^arm is directed downwards
or towards the wrist in the ordinary manner ; and in H. lav it is
nearly erect, with only a very slight fqrward inclination; so that
in this latter species it is in a transitional state. It can hardly
be doubted that with most mammals the thickness of the hair on
the back and its direction, is adapted to throw off the rain ; even
the transverse hairs on the fore- legs of a dog may serve for this
end when , he is coiled up asleep. Mr. Wallace, who has carefully
studied the habits of the orang, remarks that the convergence of
the hair towards the elbow on the arms of the orang may be
explained as serving to throw off the rain, for this animal during
rainy weather sits with its arms bent, and with the hands clasped
round a branch or over its head.. According to Livingstone, the
gorilla also " sits in pelting rain with his hands over his head," 8
If the above explanation is correct, as seems probable, the direc-
tion of the hair on our own arms offers a curious record of our
former state; for no one supposes that it is now of any use in
throwing off the rain ; nor, in our present erect condition, is it
properly directed for this purpose.
It would, however, be rash to trust too much to the principle
of adaptation in regard to the direction of the hair in man or his
* Isid. Geoffroy, * Hist. Nat. Gen.', Anat. und Phys/ 1 837, s. 51.
t«ra. ii. 1859, p. 217. 8 Quoted by Reade, * The African
7 < Ueber die Richtung der Sketch Book,' vol. i„ 1873, p. 158.
Uaare,' &c, Mtiller's 'Archir fliv
I S 2 Ttie Descent of Man. Part I.
early progenitors ; for it is impossible to study the figures given
by Eschricht of the arrangement of the hair on the human foetus
(this being the same as in the adult) and not agree with this
excellent observer that other and more complex causes havo
intervened. The points of convergence seem to stand in somo
relation to those points in the embryo which are last closed in
during development. There appears, also, to exist some relation
between the arrangement of the hair on the limbs, and the course
of the medullary arteries. 9
It must not be supposed that the resemblances between man
and certain apes in the above and many other points — such as in
having a naked forehead, long tresses on the head, &c. — are all
necessarily the result of unbroken inheritance from a common
progenitor, or of subsequent reversion. Many of these resem-
blances are more probably due to analogous variation, which
follows, as I have elsewhere attempted to shew, 10 from co-descended
organisms having a similar constitution, and having been acted on
by like causes inducing similar modifications. With respect to
the similar direction of the hair on the fore-arms of man and
certain monkeys, as this character is common to almost all the
anthropomorphous apes, it may probably be attributed to in-
heritance; but this is not certain, as some very distinct American
monkeys are thus characterised.
Although, as we have now seen, man has no just right to form
a separate Order for his own reception, he may perhaps claim a
distinct Sub-order or Family. Prof. Huxley, in his last work,"
divides the Primates into three Sub-orders ; namely, the An-
thropidae with man alone, the Simiadae including monkeys of all
kinds, and the LemuridaB with the diversified genera of lemurs.
As far as differences in certain important points of structure are
concerned, man may no doubt rightly claim the rank of a Sub-
order ; and this rank is too low, if we look chiefly to his mental
faculties. Nevertheless, from a genealogical point of view it
appears that this rank is too high, and that man ought to form
merely a Family, or possibly even only a Sub-family. If wo
imagine three lines of descent proceeding from a common stock,
it is quite conceivable that two of them might after the lapse of
• On the hair in Hylobates, see the Theory of Natural Selection,*
Nat. Hist, of Mammals,' by C. L. 1870, p. 344.
Martin, 1841, p. 415. Also, Isid. 10 'Origin of Species,' 5th edit.
GeoSroy on the American monkeys 1869, p. 194. 'The Variation of
and other kinds, ' Hist. Nat. Gen.* Animals and Plants under Domesti-
voi. ii. 1859, p. 216, 243. Esch- cation/ vol. ii. 1868, p. 348.
richt, ibid. s. 46, 55, 61. Owen, n ' An Introduction to the Clamj'
'Anat. of Vertebrates,' vol. iii. p. firation of Aaimals/ 1869, p. 99.
619. Wallace, ' Contributions to
Chap. VI. Affinities and Genealogy, 153
ages be so slightly changed as still to remain as species of the
same genus, whilst the third line might become so greatly
modified as to deserve to rank as a distinct Sub-family, Family,
or even Order. But in this case it is almost certain that the
third line would still retain through inheritance numerous small
points of resemblance with the other two. Here, then, would
occur the difficulty, at present insoluble, how much weight we
ought to assign in our classifications to strongly-marked dif-
ferences in some few points, — that is, to the amount of modifi-
cation undergone ; and how much to close resemblance in
numerous unimportant points, as indicating the lines of descent
or genealogy. To attach much weight to the few but strong
differences is the most obvious and perhaps the safest course,
though it appears more correct to pay great attention to the
many small resemblances, as giving a truly natural classification.
In forming a judgment on this head with reference to man, we
must glance at the classification of the Simiadae. This family is
divided by almost all naturalists into the Catarhine group, or
Old World monkeys, all of which are characterised (as their
name expresses) by the peculiar structure of their nostrils, and by
having four premolars in each jaw ; and into the Platyrhine
group or New World monkeys (including two very distinct
sub-groups), all of which are characterised by differently
constructed nostrils, and by having six premolars in each jaw.
Some other small differences might be mentioned. Now man
unquestionably belongs in his dentition, in the structure of his
nostrils, and some other respects, to the Catarhine or Old World
division ; nor does he resemble the Platyrhines more closely than
the Catarhines in any characters, excepting in a few of not much
importance and apparently of an adaptive nature. It is therefore
against all probability that some New World species should have
formerly varied and produced a man-like creature, with all the
distinctive characters proper to the Old World division; losing
at the same time all its own distinctive characters. There can,
consequently, hardly be a doubt that man is an off-shoot from the
Old World Simian stem ; and that under a genealogical point of
view, he must be classed with the Catarhine division. 12
The anthropomorphous apes, namely the gorilla, chimpanzee,
12 This is nearly the same classifi- adse which answer to the Catarhines,
cation as that provisionally adopted the Cebidae, and the Hapalidae. —
bv Mr. St. George Mivart ( 4 Tran- these two latter groups answering
aact. Philosoph. Soc* 1867, p. 300), to the Platyrhines. Mr. Mivart
who, after separating the Lemuridae, still abides by the same view ; see
divides the remainder of the Pri- * Nature,' 1871, p. 481,
mau» into the Hommidae, th« Sinu*
1 54 The Descent of Man. Part L
orang, and hylobates, are by most naturalists separated from the
other Old World monkeys, as a distinct sub-group. I am aware
that Gratiolet, relying on the structure of the brain, does not
* admit the existence of this sub-group, and no doubt it is a broken
one. Thus the orang, as Mr. St. G. Mivart remarks, 18 " is one of the
" most peculiar and aberrant forms to be found m the Order."
The remaining non-anthropomorphous Old World monkeys, are
again divided by some naturalists into two or three smaller sub-
groups ; the genus Semnopithecus, with its peculiar sacculated
stomach, being the type of one such sub-group. But it appears
from M. Gaudry's wonderful discoveries in Attica, that during
the Miocene period a form existed there, which connected
Semnopithecus and Macacus ; and this probably illustrates the
manner in which the other and higher groups were once blended
together.
If the anthropomorphous apes be admitted to form a natural
sub-group, then as man agrees with them, not only in all thoso
characters which he possesses in common with the whole
Catarhine group, but in other peculiar characters, such as the
absence of a tail and of callosities, and in general appearance, we
may infer that some ancient member* of the anthropomorphous
sub-group gave birth to man. It is not probable that, through
the law of analogous variation, a member of one of the other
lower sub-groups should have given rise to a man-like creature,
resembling the higher anthropomorphous apes in so many
respects. No doubt man, in comparison with most of his allies,
has undergone an extraordinary amount of modification, chiefly
in consequence of the great development of his brain and his
erect position ; nevertheless, we should bear in mind that he " is
" but one of several exceptional forms of Primates." 14
Every naturalist, who believes in the principle of evolution,
will grant that the two main divisions of the Simiadse, namely
the Catarhine and Platyrhine monkeys, with their sub-groups,
have all proceeded from some one extremely ancient progenitor.
The early descendants of this progenitor, before they had
diverged to any considerable extent from each other, would still
have formed a single natural group ; but some of the species or
incipient genera would have already begun to indicate by their
diverging characters the future distinctive marks of the Catarhine
and Platyrhine divisions. Hence the members of this supposed
ancient group would not have been so uniform in their den-
tition, or in the structure of their nostrils, as are the existing
l * l Transact. Zoolog. Soc/ vol. vi. u Mr. St. G. Mivart, 4 Traaaaet.
1867, p. 214. Phil. Soc' 1867, p. 410.
Chap. VI. Affinities and Genealogy. 1 55
Catarhine monkeys in one way and the Platyrhines in another
way, but would have resembled in this respect the allied Lemu-
ridso, which differ greatly from each other in the form of their
muzzles, 15 and to an extraordinary degree in their dentition.
The Catarhine and Platyrhine monkeys agree in a multitude
of characters, as is shewn by their unquestionably belonging
to one and the same Order. The many characters which
they possess in common can hardly have been independently
acquired by so many distinct species ; so that these characters
must have been inherited. But a naturalist would undoubtedly
have ranked as an ape or a monkey, an ancient form which
possessed many characters common to the Catarhine and
Platyrhine monkeys, other characters in an intermediate con-
dition, and some few, perhaps, distinct from those now found in
either group. And as man from a genealogical point of view
belongs to the Catarhine or Old World stock, we must conclude,
however much the conclusion may revolt our pride, that our
early progenitors would have been properly thus designated. 16
But we must not fall into the error of supposing that the early
progenitor of the whole Simian stock, including man, was iden-
tical with, or even closely resembled, any existing ape or monkey.
On the Birthplace and Antiquity of Man. — We are naturally
led to enquire, where was the birthplace of man at that stage of
descent when our progenitors diverged from the Catarhine
stock ? The fact that they belonged to this stock clearly shews
that they inhabited the Old World ; but not Australia nor any
oceanic island, as we may infer from the laws of geographical
distribution. In each great region of the world the living
mammals are closely related to the extinct species of the same
region. It is therefore probable that Africa was formerly in-
habited by extinct apes closely allied to the gorilla and chim-
panzee; and as these two species are now man's nearest allies, it
is somewhat more probable that our early progenitors lived on
the African continent than elsewhere. But it is useless to
speculate on this subject; for two or three anthropomorphous
apes, one the Dryopithecus 17 of Lartet, nearly as large as a man,
15 Messrs Murie and Mivart on his ' Natttrliche Schopfungsge-
Ihe Lemuroidea, * Transact. Zoolog. schichte,' 1868, in which he gives
Soc.' vol. vii. 1869, p. 5. in detail his views on the genealogy
18 Hack el has come to this same of man.
conclusion. See *Ueber die Ent- 1T Dr. C. Forsyth Major, 'Sur le&
stehung des Menschengeschlechts,' Singes Fossiles trouv^s en Italie t
in Virchow's * Sammlung. gemein. 'Socltal. des sc Nat." torn. x v. 1872
wissen. Vortrage/ 1868, s. 61. Also
156 The Descent cj Man. Past I
and closely allied to Hylobates, existed in Europe during the
Miocene age; and since so remote a period the earth has
certainly undergone many great revolutions, and there has been
ample time for migration on the largest scale.
At the period and place, whenever and wherever it was, when
man first lost his hairy covering, he probably inhabited a hot
country ; a circumstance favourable for the frugiferous diet on
which, judging from analogy, he subsisted. We are far from
knowing how long ago it was when man first diverged from the
Catarhine stock ; but it may have occurred at an epoch as remote
as the Eocene period; for that the higher apes had diverged
from the lower apes as early as the Upper Miocene period is
shewn by the existence of the Dryopithecus. We are also quite
ignorant at how rapid a rate organisms, whether high or low in
the scale, may be modified under favourable circumstances ; we
know, however, that some have retained the same form during
an enormous lapse of time. From what we see going on undei
domestication, we learn that some of the co-descendants of the
game species may be not at all, some a little, and some greatly
changed, all within the same period. Thus it may have been
with man, who has undergone a great amount of modification
in certain characters in comparison with the higher apes.
The great break in the organic chain between man and his
nearest allies, which cannot be bridged over by any extinct or
living species, has often been advanced as a grave objection to
the belief that man is descended from some lower form; but this
objection will not appear of much weight to those who, from
general reasons, believe in the general principle of evolution.
Breaks often occur in all parts of the series, some being wide,
sharp and defined, others less so in various degrees ; as between
the orang and its nearest allies — between the Tarsius and the
other Lemuridae — between the elephant, and in a more striking
manner between the Ornithorhynchus or Echidna, and all other
mammals. But these breaks depend merely on the number of
related forms which have become extinct. At some future
period, not very distant as measured by centuries, the civilised
races of man will almost certainly exterminate, and replace, the
savage races throughout the world. At the same time the anthro-
pomorphous apes> as Professor Schaafifhausen has remarked, 18
will no doubt be exterminated. The break between man and his
nearest allies will then be wider, for it will intervene between
man in a more civilised state, as we may hope, even than the
Caucasian, and some ape as low as a baboon, instead of as now
between the negro or Australian and the gorilla.
-• Anthropological Review,' April, 1867, p. 236.
ChaaVI. Affinities and Genealogy. i$7
With respect to the absence of fossil remains, serving to
connect man with his ape-like progenitors, no one will lay much
stress on this fact who reads Sir C. LyelPs discussion, 1 * where
he shews that in all the vertebrate classes the discovery of fossil
remains has been a very slow and fortuitous process. Nor
should it be forgotten that those regions which are the most
likely to afford remains connecting man with some extinct ape-
like creature, have not as yet been searched by geologists.
Lovjer Stages in the Genealogy of Man. — "We have seen that
man appears to have diverged from the Catarhine or Old World
division of the Simiadss, after these had diverged from the New
World division. We will now endeavour to follow the remote
traces of his genealogy, trusting principally to the mutual
affinities between the various classes and orders, with some
slight reference to the periods, as far as ascertained, of their
successive appearance on the earth. The Lemuridae stand
below and near to the Simiadae, and constitute a very distinct
family of the Primates, or, according to Hackel and others, a
distinct Order. This group is diversified and broken to an
extraordinary degree, and includes many aberrant forms. It
has, therefore, probably suffered much extinction. Most of the
remnants survive on islands, such as Madagascar and the
Malayan archipelago, where they have not been exposed to so
severe a competition as they would have been on well-stocked
continents. This group likewise presents many gradations,
leading, as Huxley remarks, 20 " insensibly from the crown and
" summit of the animal creation down to creatures from which
" there is but a step, as it seems, to the lowest, smallest, and
" least intelligent of the placental mammalia." From these
various considerations it is probable that the Simiada3 were
originally developed from the progenitors of the existing
Lemuridae ; and these in their turn from forms standing very
low in the mammalian series.
The Marsupials stand in many important characters below the
placental mammals. They appeared at an earlier geological
period, and their range was formerly much more extensive
than at present. Hence the Placentata are generally supposed
to have been derived from the Implacentata or Marsupials;
not, however, from forms closely resembling the existing Mar-
supials, but from their early progenitors. The Monotremata are
plainly allied to the Marsupials, forming a third and still lower
w * Elements of Geology/ 1865, 20 ' Man's Place in ft&lnxt, jv
pp. 583-585, * Antiquity of Man.' 105.
l«33* p. H5.
158 The Descent of Man. Pakt I
division in the great mammalian series. They are represented
at the present day solely by the Ornithorhynchus and Echidna ;
and these two forms may be safely considered as relics of a
much larger group, representatives of which have been preserved
in Australia through some favourable concurrence of circum-
stances. The Monotremata are eminently interesting, as leading
m several important points of structure towards the class of
reptiles.
In attempting to trace the genealogy of the Mammalia, and
therefore of man, lower down in the series, we become involved
in greater and greater obscurity; but as a most capable judge,
Mr. Parker, has remarked, we have good reason to believe, that
no true bird or reptile intervenes in the direct line of descent.
He who wishes to see what ingenuity and knowledge can effect,
may consult Prof. Hackers works. 21 I will content myself with
a few general remarks. Every evolutionist will admit that the
five great vertebrate classes, namely, mammals, birds, reptiles,
amphibians, and fishes, are descended from some one prototype ;
for they have much in common, especially during their embryonic
state. As the class of fishes is the most lowly organised, and
appeared before the others, we may conclude that all the
members of the vertebrate kingdom are derived from some fish-
like animal. The belief that animals so distinct as a monkey,
an elephant, a humming-bird, a snake, a frog, and a fish, &c, could
all have sprung from the same parents, will appear monstrous
to those who have not attended to the recent progress of natural
history. For this belief implies the former existence of links
binding closely together all these forms, now so utterly unlike.
Nevertheless, it is certain that groups of animals have existed,
or do now exist, which serve to connect several of the great
vertebrate classes more or less closely. We have seen that the
Ornithorhynchus graduates towards reptiles ; and Prof. Huxley
has discovered, and is confirmed by Mr. Cope and others, that
the Dinosaurians are in many important characters intermediate
between certain reptiles and certain birds — the birds referred
to being the ostrich-tribe (itself evidently a widely-diffused
remnant of a larger group) and the Archeopteryx, that strange
Secondary bird, with a long lizard-like tail. Again, according to
21 Elaborate tables are given in the phylum or lines of descent of
his * Generelle Morphologie ' (B. ii. the Vertebrata to be admirably dis-
5. cliii. and s. 425); and with more cussed by Hackel, although he differs
especial reference to man in his on some points. He expresses,
'Naturliche Schopfungsgeschichte/ also, his high estimate of the
1868. Prof. Huxley, in reviewing general tenor and spirit of th«
this latter work ('The Academy/ whole work.
1868, p. 42) says, that he considers n Palaeontology/ I860, p. 199,
Chap. VI. Affinities and Genealogy, 159
Prof. Owen, 22 the Ichthyosaurians— great sea-lizards furnished
with paddles— present many affinities with fishes, or rather,
according to Huxley, with amphibians; a class which, including
in its highest division frogs and toads, is plainly allied to tho
Ganoid fishes. These latter fishes swarmed during the earlier
geological periods, and were constructed on what is called a
generalised type, that is, they presented diversified affinities with
other groups of organisms. The Lepidosiren is also so closely
allied to amphibians and fishes, that naturalists long disputed in
which of these two classes to rank it; it, and also some few
Ganoid fishes, have been preserved from utter extinction by
inhabiting rivers, which are harbours of refuge, and are related
to the great waters of the ocean in the same way that islands
are to continents.
Lastly, one single member of the immense and diversified class
of fishes, namely, the lancelet or amphioxus, is so different from
all other fishes, that Hackel maintains that it ought to form a
distinct class in the vertebrate kingdom. This fish is remarkable
for its negative characters ; it can hardly be said to possess a
brain, vertebral column, or heart, &c. ; so that it was classed by
the older naturalists amongst the worms. Many years ago Prof.
Goodsir perceived that the lancelet presented some affinities with
the Ascidians, which are invertebrate, hermaphrodite, marine
creatures permanently attached to a support. They hardly
appear like animals, and consist of a simple, tough, leathery
sack, with two small projecting orifices. They belong to the
Moliuscoida of Huxley — a lower division of the great kingdom
of the Mollusca; but they have recently been placed by some
naturalists amongst the Vermes or worms. Their larvae some-
what resemble tadpoles in shape, 23 and have the power of
swimming freely about. M.Kovalevsky 24 has lately observed that
the larvaa of Ascidians are related to the Vertebrata, in their
manner of development, in the relative position of the nervous
system, and in possessing a structure closely like the chorda
dorsalis of vertebrate animals; and in this he has been since
2S At the Falkland Islands I had under a simple microscope, plainly
the satisfaction of seeing, in April divided by transverse opaque parti*
1833, and therefore some years be- tions, which I presume represent
fore any other naturalist, the loco- the great cells figured by Kovalev-
raotive larva; of a compound Asci- sky. At aa early stage of develop-
dian, closely allied to Synoicum, ment the tail was closely coilȣ
but apparently generically distinct round th« head of the larva,
from it. The tail was about five 2 * ■* Memoires de l'Acad. dei
times as long as the oblong head, Sciences de St. Petersbourg/ torn: x
and terminated in a very fine fila- No. 15, 1866.
iHifnt. It was, as sketched by me
r DO The Descent of Man. Far? L
confirmed i.\> 7 Prof. Kupifer. M. Kovalevsky writes to me from
Naples, that he has now carried these observations yet further ,
and should his results be well established, the whole will form a
discovery of the very greatest value. Thus, if we may rely on
embryology, ever the safest guide in classification, it seems that
we have at last gained a clue to the source whence the Vertebrata
were derived. 23 We should then be justified in believing
that at an extremely remote period a group of animals existed,
resembling in many respects the larva) of our present Ascidians,
which diverged into two great branches— the one retrograding in
development and producing the present class of Ascidians,- the
other rising to the crown and summit of the animal kingdom by
giving birth to the Vertebrata.
We have thus far endeavoured rudely to trace the genealogy
of the Vertebrata by the aid of their mutual affinities. We will
now look to man as he exists ; and we shall, I think, be able
partially to restore the structure of our early progenitors, during
successive periods, but not in due order of time. This can bo
effected by means of the rudiments which man still retains, by
the characters which occasionally make their appearance in him
through reversion, and by the aid of the principles of morphology
and embryology. The various facts, to which I shall here allude,
hayjeJbeen given in the previous chapters.
^ The early progenitors of man must have been once covered
with hair, both sexes having beards ; their ears were probably
pointed, and capable of moveruent ; and their bodies were pro-
vided with & tail, having the proper muscles. Their limbs and
bodies were also acted on by many muscles which now only
occasionally reappear, but are normally present in the Quadru-
mana. At this or some earlier period, the great artery and nerve
of the humerus ran through a supra-condyloid foramen. The
intestine gave forth a much larger diverticulum or caecum than
that now existing. The foot was then prehensile, judging from
the condition of the great toe in the foetus ; and our progenitors,
no doubt, were arboreal in their habits, and frequented some
warm, forest-clad land. The males had great canine teeth, which
85 But I am bound to add that " peut produire la disposition fonda-
soine competent judges dispute this " mentale du type vert^bre" (rex-
conclusion ; for instance, M. Giard, " istence d'une corde dorsale) chez
in a series of papers in the* Archives " un inverters' par la seule con-
de Zoologie Experi mentale,' for 1872. " dition vitale de l'adaptation,
Nevertheless, this naturalist re- " et cette simple possibility du
marks, p. 281, •* L'organisation &2 la " passage supprime Tabiinc ectre
" larve ascidienne en dehors de " les deux sous-regnes, encore bien
" toute hypotheseet detoutetheorie, " qu'en ignore par oil le passage
u oous inoctrc coaimfiit la nature " u'est fait er r4?M%6"
Chap.Vj. Affinities and Genealogy. 161
Bcrved them as formidable weapons. At a much earlier period
the uterus was double; the excreta were voided through a cloaca;
and the eye was protected by a third eyelid or nictitating mem-
brane. At a still earlier period the progenitors of man must have
been aquatic in their habits; for morphology plainly tells us that
our lungs consist of a modified swim-bladder, which once served
as a float. The clefts on the neck in the embryo of man show
where the branchiae once existed. In the lunar or weekly re-
current periods of some of our functions we apparently still retain
traces of our primordial birthplace, a shore washed by the tides.
At about this same early period the true kidneys were replaced
by the corpora wolffiana. The heart existed as a simple pulsating
vessel; and the chorda dorsalis took the place of a vertebral
column. These early ancestors of man, thus seen in the dim
recesses of time, must have been as simply, or even still more
simply organised than the lancelet or amphioxus.
There is one other point deserving a fuller notice. It has long
been known that in the vertebrate kingdom one sex bear?
rudiments of various accessory parts, appertaining to the re-
productive system, which properly belong to the opposite sex ;
and it has now been ascertained that at a very early embryonic
period both sexes possess true male and female glands. Hence
some remote progenitor of the whole vertebrate kingdom appears
to have been hermaphrodite or androgynous. 26 But here we
encounter a singular difficulty. In the mammalian class the
males possess rudiments of a uterus with the adjacent passage,
in their vesiculse prostaticsB; they bear also rudiments of
mammaB, and some male Marsupials have traces of a marsupial
sack. 27 Other analogous facts could be added. Are we, then, to
suppose that some extremely ancient mammal continued andro-
gynous, after it had acquired the chief distinctions of its class,
and therefore after ii had diverged from the lower classes of the
vertebrate kingdom ? This seems very improbable, for we have
to look to fishes, the lowest of all the classes, to find any stil!
existent androgynous forms. 28 That various accessory parts,
28 This is the conclusion of Prof. " brata are, in their early condition,
Gegenbaur, one of the highest au- " hermaphrodite." Similar views
thoiities in comparative anatomy; have lomr been held by some authors,
see ' Grundziige der vergleieh. Anat.' though until recently without a
1870, s. 876. The result has been firm basis.
arrived at chiefly from the study of 2r The male Thylacinus offers the
the Amphibia; but it appears frcm best instance. Owen, * Anatomy of
the researches of Waldeyer (as Vertebrates,' vol. iii. p. 771.
quoted in * Journal of Anat. and 28 Hermaphroditism has been ob-
PKys/ 1869, p. 161), that the sexual served in several species of Seiranus,
prg--"M of even "the higher verte- as well a> in some other fishes,
1 62 TJie Descent of Man. Part L
proper to each sex, are found in a rudimentary condition in the
opposite sex, may be explained by such organs having been
gradually acquired by the one sex, said then transmitted in a
more or less imperfect state to the other. When we treat of
sexual selection, we shall meet with innumerable instances of
this form of transmission, — as in the case of the spurs, plumes,
and brilliant colours, acquired for battle or ornament by male
birds, and inherited by the females in an imperfect or rudimentary
condition.
The possession by male mammals of functionally imperfect
mammary organs is, in some respects, especially curious. Tho
Monotremata have the proper milk-secreting glands with orifices,
but no nipples ; and as these" animals stand at the very base of
the mammalian series, it is probable that the progenitors of
the class also had milk-secreting glands, but no nipples. This
conclusion is supported by what is known of their manner of
development ; for Professor Turner informs me, on the authority
of Kolliker and Langer, that in the embryo the mammary glands
can be distinctly traced before the nipples are in the least
visible; and the development of successive parts in the indi-
vidual generally represents and accords with the development of
successive beings in the same line of descent. The Marsupials
differ from the Monotremata by possessing nipples; so that
probably these organs were first acquired by the Marsupials,
after they had diverged from, and risen above, the Monotremata,
and were then transmitted to the placental mammals. 29 No one
will suppose that the Marsupials still remained androgynous,
after they had approximately acquired their present structure.
How then are we to account for male mammals possessing
mammae ? It is possible that they were first developed in the
females and then transferred to the males ; but from what
follows this is hardly probable.
where it is either normal and sym- delle Scienze,' Bologna, Dec. 28,
metrical, or abnormal and uni- 1871) that eels are androgynous,
lateral. Dr. Zouteveen has given 29 Prof. Gegenbaur has shewn
me references on this subject, more (' Jenaische Zeitschrift,' Bd. vii. p.
especially to a paper by Prof. Hal- 212) that two distinct types of
bertsma, in the 'Transact, of the nipples prevail throughout the
Dutch Acad, of Sciences,' vol. xvi. several mammalian orders, but
Dr. Gtinther doubts the fact, but that it is quite intelligible how both
it has now been recorded by too could have been derived from the
many good observers to be any nipples of the Marsupials, and the
longer disputed. Dr. M. Lessona latter from those of the Monctre-
writes to me, that he has veri- mata. See, also, a memoir &y Dr
fied the observations made by Max Huss, on the mammary gkada,
Carolini on Serranus. Prof. Erco- ibid. B. viii. p. 176.
Uni has recently shewn (*Accad.
Chap. YL Affinities and Genealogy. 1 63
It may be suggested, as another view, that long after the
progenitors of the whole mammalian class had ceased to be
androgynous, both sexes yielded milk, and thus nourished their
young ; and in the case of the Marsupials, that both sexes carried
their young in marsupial sacks. This will not appear altogether
improbable, if we reflect that the males of existing syngnatbous
fishes receive the eggs of the females in their abdominal pouches,
hatch them, and afterwards, as some believe, nourish the
young ; 80 — that certain other male fishes hatch the eggs within
their mouths or branchial cavities; — that certain male toads
take the chaplets of eggs from the females, and wind them round
their own thighs, keeping them there until the tadpoles are
born;— that certain male birds undertake the whole duty of
incubation, and that male pigeons, as well as the females, feed
their nestlings with a secretion from their crops. But the above
suggestion first occurred to me from the mammary glands of
male mammals being so much more perfectly developed than
the rudiments of the other accessory reproductive parts, which
are found in the one sex though proper to the other. The
mammary glands and nipples, as they exist in male mammals,
can indeed hardly be called rudimentary ; they are merely not
fully developed, and not functionally active. They are sympa-
thetically affected under the influence of certain diseases, like
the same organs in the female. They often secrete a few drops
of milk at birth and at puberty : this latter fact occurred in the
curious case, before referred to, where a young man possessed
two pairs of mammae. In man and some other male mammals
these organs have been known occasionally to become so well
developed during maturity as to yield a fair supply of milk.
Now if we suppose that during a former prolonged period male
mammals aided the females in nursing their offspring, 81 and that
afterwards from some cause (as from the production of a smaller
number of young) the males ceased to give this aid, disuse of the
organs during maturity would lead to their becoming inactive ;
and from two well-known principles of inheritance, this state of
inactivity would probably be transmitted to the males at the
corresponding ago of maturity. But at an earlier age these
80 Mr. Lockwood believes (as by Prof. Wyman, in ' Proc. Boston
quoted in* Quart. Journal of Science,' Soc. of Nat. Hist.* Sept. 15,1857;
April, 1868, p. 269), from what he also Prof. Turner, in 'Journal oi
has observed of the development of Anat. and Phys/ Nov. .1, 1866, p.
Hippocampus, that the walls of the 78. Dr. Giinther has likewise d§-
abdominal pouch of the male in scribed similar cases,
some way afford nourishment. On 31 Madlle. C. Royer has suggested
male fishes hatching the ova in their a similar view in her *Origlrse de
jcjouths, see a very interesting papcz PHomasb ' &c, 1870.
M 2
X&4 The Descent of Man. Par* I,
organs would be left unaffected, so that they would be almost
equally well developed in the young of both sexes.
Conclusion. — Von Baer has defined advancement or progress in
the organic scale better than any one else, as resting on the
amount of differentiation and specialisation of the several parts
of a being, — when arrived at maturity, as I should be inclined to
add. Now as organisms have become slowly adapted to diver-
sified lines of Life by means of natural selection, their parts will
have become more and more differentiated and specialised for
various functions, from the advantage gained by the division of
physiological labour. The same part appears often to have been
modified first for one purpose, and then long afterwards for
some other and quite distinct purpose ; and thus all the parts
/are rendered more and more complex. But each organism still
I retains the general type of structure of the progenitor from
I which it was aboriginally derived. In accordance with this
view it seems, if we turn to geological evidence, that organisa-
tion on the whole has advanced throughout the world by slow
and interrupted steps. In the great kingdom of the Vertebrata
it has culminated in man. It must not, however, be supposed
that groups of organic beings are always supplanted, and dis-
appear as soon as they have given birth to other and more
perfect groups. The latter, though victorious over their pre-
decessors, may not have become better adapted for all places in
the economy of nature. Some old forms appear to have survived
from inhabiting protected sites, where they have not been
exposed to very severe competition ; and these often aid us in
constructing our genealogies, by giving us a fair idea of former
and lost populations. But we must not fall into the error of
looking at the existing members of any lowly-organised group as
perfect representatives of their ancient predecessors.
The most ancient progenitors in the kingdom of the Vertebrata,
at which we are able to obtain an obscure glance, apparently
consisted of a group of marine animals, 32 resembling the larvae of
existing Ascidians. These animals probably gave rise to a
82 The inhabitants of the sea- ditions for many generations, can
shore must be greatly affected by hardly fail to run their course in
the tides; animals living either regular weekly periods. Now it is a
about the mean high-water mark, mysterious fact that in the higher
or about the mean low-water mark, and now terrestrial Vertebrata, as
*>a«s through a complete cycle of well as in other classes, many nor-
tidal changes in a fortnight. Con- mal and abnormal processes have
sequently, their food supply will one or more whole weeks as their
undergo marked changes week by periods ; this would be rendered
week. The vital functions of such intelligible if the Vertebrata are do-
tiumals. living under these con- scended from an animal allied U
Chap. VI. Affinities and Genealogy. 165
group of fishes, as lowly organised as the lancelet; and from
these the Ganoids, and other fishes like the Lepidosiren, must
nave been developed. From such fish a very small advauce
would carry us on to the Amphibians. We have seen that birds
and reptiles were once intimately connected together ; and the
Monotremata now connect mammals with reptiles in a slight
degree. But no one can at present say by what line of descent
the three higher and related classes, namely, mammals, birds,
and reptiles, were derived from the two lower vertebrate classes,
namely, amphibians and fishes. In the class of mammals the
stops are not difficult to conceive which led from the ancient
Monotremata to the ancient Marsupials; and from these to the
early progenitors of the placental mammals. We may thus
ascend to the Lemuridse ; and the interval is not very wide from
these to the Simiadae. The Simiad® then branched off into two
great stems, the New World and Old World monkeys ; and from
the latter, at a remote period, Man, the wonder and glory of the
Universe, proceeded.
Thus we have given to man a pedigree of prodigious length, but
not, it may be said, of noble quality. The world, it has often
been remarked, appears as if it had long been preparing for the
advent of man : and this, in one sense is strictly true, for he
owes his birth to along line of progenitors. If any single link
in this chain had never existed, man would not have been exactly
what he now is. Unless we wilfully close our eyes, we may, with
our present knowledge, approximately recognise our parentage ;
nor need we feel ashamed of it. The most humble organism is
something much higher than the inorganic dust under our feet ;
and no one with an unbiassed mind can study any living
creature, however humble, without being struck with enthusiasm
at its marvellous structure and properties.
the existing tidal Ascidians. Many cess or function, would not, when
instances of such periodic processes once gained, be liable to change;
might be given, as the gestation of consequently it might be thus trans-
mammals, the duration of fevers, &c. mitted through almost any number
The hatching of eggs affords also a of generations. Bat if the function
good example, for, according to Mr. changed, the period would have to
Bartlett (* Land and Water,' Jan. 7, change, and would be apt to change
1871), the eggs of the pigeon are almost abruptly by a whole week,
hatched in two weeks ; those of the This conclusion, if sound, is highly
fowl in three ; those of the duck in remarkable ; for the period of gesta-
fo ir ; those of the goose in five ; tion in each mammal, and the
and those of the ostrich in seven hatching of each bird's eggs, and
weeks. As far as we can judge, a many other vital processes, thus
recurrent period, if approximately betray to us the primordial birfch-
©f the right duration for any pro- place of these animals.
1 66 The Descent of Man. Part I
CHAPTER VII.
On the Races of Man.
Hie nature and value of specific characters — Application to tha races of
man — Arguments in favour of, and opposed to, ranking the so-called
races of man as distinct species — Sub-species — Monogenists and poly-
genists — Convergence of character — Numerous points of resemblance in
body and mind between the most distinct races of man — The state of
man when he first spread over the earth — Each race not descended from
a single pair — The extinction of races — The formation ot races — The
effects of crossing — Slight influence of the direct action of the con-
ditions of life — Slight or no influence of natural selection — Sexual
selection.
It is not my intention here to describe the several so-called races
of men; but I am about to enquire what is the value of the dif-
ferences between them under a classificatory point of view, and
how they have originated. In determining whether two or more
allied forms ought to be ranked as species or varieties, naturalists
are practically guided by the following considerations; namely, the
amount of difference between them, and whether such differences
relate to few or many points of structure, and whether they are
of physiological importance ; but more especially whether they
are constant. Constancy of character is what is chiefly valued
and sought for by naturalists. Whenever it can be shewn, or
rendered probable, that the forms in question have remained
distinct for a long period, this becomes an argument of much
weight in favour of treating them as species. Even a slight
degree of sterility between any two forms when first crossed, or
in their offspring, is generally considered as a decisive test of
their specific distinctness; and their continued persistence
without blending within the same area, is usually accepted as
sufficient evidence, either of some degree of mutual sterility, or
in the case of animals of some mutual repugnance to pairing.
Independently of fusion from intercrossing, the complete
absence, in a well-investigated region, of varieties linking
together any two closely-allied forms, is probably the most
important of all the criterions of their specific distinctness ; and
this is a somewhat different consideration from mere constancy
j of character, for two forms may be highly variable and yet not
I yield intermediate varieties. Geographical distribution is often
brought into play unconsciously and sometimes consciously ; so
that forms living in two widely separated areas, in which most
Chap. VIL The Races of Man. 167
of ;fche other inhabitants are specifically distinct, are themselves
usually looked at as distinct ; but in truth this affords 110 aid in dis-
tinguishing geographical races from so-called good or true species.
Now let us apply these generally-admitted principles to the
races of man, viewing him in the same spirit as a naturalist would
any other animal. In regard to the amount of difference between
the races, we must make some allowance for our nice powers of
discrimination gained by the long habit of observing ourselves.
In India, as Elphinstone remarks, although a newly-arrived
European cannot at first distinguish the various native races,
yet they soon appear to him extremely dissimilar j 1 and the
Hindoo cannot at first perceive any difference between the several
European nations. Even the most distinct races of man are
much more like each other in form than would at first be sup
posed ; certain negro tribes must be excepted, whilst others, as
Dr. Kohlfs writes to me, and as I have myself seen, have
Caucasian features. This general similarity is well shewn by
the French photographs in the Collection Anthropologique du
Museum de Paris of the men belonging to various races, the
greater number of which might pass for Europeans, as many
persons to whom I have shewn them have remarked. Neverthe-
less, these men, if seen alive, would undoubtedly appear very
distinct, so that we are clearly much influenced in our judgment
by the mere colour of the skin and hair, by slight differences in
the features, and by expression.
There is, however, no doubt that the various races, when \
carefully compared and measured, differ much from each other, !
— as in the texture of the hair, the relative proportions of all parts ■
of the body, 8 the capacity of the lungs, the form and capacity of \
the skull, and even in the convolutions of the brain. 3 But it
would be an endless task to specify the numerous points of
difference. The races differ also in constitution, in acclimatisation
and in liability to certain diseases. Their mental characteristics
are likewise very distinct ; chiefly as it would appear in their
emotional, but partly in their intellectual faculties. Every one
who has had the opportunity of comparison, must have been
1 * History of India,' 1841, vol. i. * On the<capacity of the lungs,* p. 471.
p. 323. Father Ripa makes exactly See **" the numerous and valuable
the same remark with respect to tables, jby Dr. Weisbach, from the
the Chinese. observations of Dr. Scherzer and
2 A vast number of measure- Dr. Schwarz, in the 'Reise der
ments cf Whites, Blacks, and In- Novara: Anthropolog. Theil/ 1867.
dians, are given in the ' Investiga- 3 See, for instance, Mr. Marshall's
tions in the Military and Anthropo- account of the brain of a Bush-
log. Statistics of American Soldiers,' woman, in * Phil. Transact.' 1804,
Dy B. A, Gould, 1869, pp. 298-358 ; p, 519.
168 The Descent of Man, Part L
struck with the contrast between the taciturn, even morose,
aborigines of S. America and the light-hearted, talkative negroes.
There is a nearly similar contrast between the Malays and the
Papuans, 4 who live under the same physical conditions, and are
separated from each other only by a narrow space of sea.
We will first consider the arguments which may be advanced
in favour of classing the races of man as distinct species, and
then the arguments on the other side. If a naturalist, who had
never before seen a Negro, Hottentot, Australian, or Mongolian,
were to compare them, he would at once perceive that they
differed in a multitude of characters, some of slight and some of
considerable importance. On enquiry he would find that they
were adapted to live under widely different climates, and that
they differed somewhat in bodily constitution and mental dis-
position. If he were then told that hundreds of similar specimens
could be brought from the same countries, he would assuredly
declare that they were as good species as many to which he had
been in the habit of affixing specific names. This conclusion
would be greatly strengthened as soon as he had ascertained that
these forms had all retained the same character for many
centuries ; and that negroes, apparently identical with existing
negroes, had lived at least 4000 years ago. 5 He would also hear,
on the authority of an excellent observer, Dr. Lund, 6 that the
human skulls found in the caves of Brazil, entombed with many
extinct mammals, belonged to the same type as that now pre-
vailing throughout the American Continent.
4 Wallace, * The Malay Archi- man ('Races of Man,' 1850, p. 201),
pelago/ vol. ii. 1869, p. 178. speaking of young Menmon (the
6 With respect to the figures in same as Rameses 11., as I am in-
the famous Egyptian caves of Abou- formed by Mr. Birch), insists in the
Simbel, M. Pouched says (' The strongest manner that he is identical
Plurality of the Human Races,* Eng. in character with the Jews of Ant-
translat. 1864, p. 50), that he was werp. Again, when I looked at the
far from finding recognisable repre- statue of Amunoph III., I agreed with
sentations of the dozen or more two officers of the establishment,
nations which some authors believe both competent judges, that he had
that they can recognise. Even some a strongly marked negro type of
of the most strongly-marked races features ; but Messrs. Nott and
cannot, be identified with tl|t de- Gliddon (ibid. p. 146, fig. 53) de-
vice of unanimity which migi- we scribe him as a hybrid, but not of
been expected from what hsf 'been " negro intermixture."
written on the subject. Thus 6 As quoted by Nott and Gliddon,
Messrs. Nott and Gliddon ('Types * Types of Mankind,' 1854, p. 439.
of Mankind,* p. 148) state that They give also corroborative evi-
Ramefcs II., or the Great, has dence ; but C. Vogt thinks that the
features superbly European ; where- subject requires further investigar
as Knox, another firm believer in tion.
the specific distinctness of the races of
Chap. VII. The Races of Man. 169
Our naturalist would then perhaps turn to geographical dis-
tribution, and he would probably declare that those forms must
be distinct species, which differ not only in appearance, but
are fitted for hot, as well as damp or dry countries, and for the
Arctic regions. He might appeal to the fact that no species in
the group next to man, namely the Quadrumana, can resist a low
temperature, or any considerable change of climate ; and that
the species which come nearest to man have never been reared
to maturity, even under the temperate climate of Europe. He
would be deeply impressed with the fact, first noticed by Agassiz, 7
that the different races of man are distributed over the world in
the same zoological provinces, as those inhabited by undoubtedly
distinct species and genera of mammals. This is manifestly the
case with the Australian, Mongolian, and Negro races of man ; in
a less well-marked manner with the Hottentots; but plainly
with the Papuans and Malays, who are separated, as Mr. Wallace
has shewn, by nearly the same line which divides the great
Malayan and Australian zoological provinces. The Aborigines
of America range throughout the Continent ; and this at first
appears opposed to the above rule, for most of the productions of
the Southern and Northern halves differ widely : yet some few
living forms, as the opossum, range from the one into the other,
as did formerly some of the gigantic Edentata. The Esquimaux,
like other Arctic animals, extend round the whole polar regions.
It should be observed that the amount of difference between tho
mammals of the several zoological provinces does not correspond
with the degree of separation between the latter ; so that it can
hardly be considered as an anomaly that the Negro differs more,
and the American much less from the other races of man, than
do the mammals of the African and American continents from
the mammals of the other provinces. Man, it may be added,
does not appear to have aboriginally inhabited any oceanic island ;
and in this respect he resembles the other members of his class.
In determining whether the supposed varieties of the same
kind of domestic animal should be ranked as such, or as spe-
cifically distinct, that is, whether any of them are descended from
distinct wild species, every naturalist would lay much stress on
the fact of their external parasites being specifically distinct.
All the more stress would be laid on this fact, as it would be an
exceptional one ; for I am informed by Mr. Denny that the most
different kinds of dogs, fowls, and pigeons, in England, are
infested by the same species of Pediculi or lice. Now Mr. A.
Murray has carefully examined the Pediculi collected in different
7 'Diversity of Origin of the Human Races,' in the * Christ in
Examiner,' July 1850.
170 The Desc&it of Man. Past 1,
countries from the different races of man; 8 and he finds that
they differ, not only in colour, but in the structure of their
claws and limbs. In every case in which many specimens were
obtained the differences were constant. The surgeon of a whaling
ship in the Pacific assured me that when the Pediculi, with
which some Sandwich Islanders on board swarmed, strayed on
to the bodies of the English sailors, they died in the course of
three or four days. These Pediculi were darker coloured, and
appeared different from those proper to tbe natives of Chiloe in
South America, of which he gave me specimens. These, again,
appeared larger and much softer than European lice. Mr.
Murray procured four kinds from Africa, namely from the Negroes
of the Eastern and Western coasts, from the Hottentots and
Kaffirs ; two kinds from the natives of Australia ; two from North
and two from South America. In these latter cases it may be
presumed that the Pediculi came from natives inhabiting different
districts. With insects slight structural differences, if constant^
are generally esteemed of specific value: and the fact of the
races of man being infested by parasites, which appear to be
specifically distinct, might fairly be urged as an argument that
the races themselves ought to be classed as distinct species.
Our supposed naturalist having proceeded thus far in his
investigation, would next enquire whether the races of men, when
crossed, were in any degree sterile. He might consult the work 9
of Professor Broca, a cautious and philosophical observer, and in
this he would find good evidence that some races were quite
fertile together, but evidence of an opposite nature in regard to
other races. Thus it has been asserted that the native women of
Australia and Tasmania rarely produce children to European
men ; the evidence, however, on this head has now been shewn
to be almost valueless. The half-castes are killed by the pure
blacks : and an account has lately been published of eleven half-
caste youths murdered and burnt at the same time, whose
remains were found by the police. 10 Again, it has often been
said that when mulattoes intermarry they produce few children;
on the other hand, Br. Bachman of Charleston 11 positively
8 'Transact. R. Soc. of Edinburgh/ who have borne children to a white
vol. xxii. 1861, p. 567. man are afterwards sterile with
9 * On the Phenomena of Hybridity their own race, is disproved. M. A.
in the Genus Homo,* Eng. translat. de Quatrefages has also collected
1864. ('Revue des Cours Scientifiques/
10 See the interesting letter by March 1869, p. 239) much evidence
Mr. T. A. Murray, in the ' Anthro- that Australians and Europeans are
polog. Review/ April 1868, p. liii. not sterile when crossed.
In this letter Count Strzeleck's n 'An Examination of Prof.
gtatement, that Australian women Agassiz's Sketch of the Nat. Pro-
Ohap. VII. The Races of Man. 171
asserts that he has known mulatto families which have inter-
married for several generations, and have continued on an
average as fertile as either pure whites or pure blacks. Enquiries
formerly made by Sir C. Lyell on this subject led him, as he
informs me, to the same conclusion. 12 In the United States the
census for the year 1854 included, according to Dr. Bachman,
405,751 mulattoes ; and this number, considering all the circum-
stances of the case, seems small ; but it may partly be accounted
for by the degraded and anomalous position of the class, and by
the profligacy of the women. A certain amount of absorption of
mulattoes into negroes must always be in progress; and this
would lead to an apparent diminution of the former. The inferior
vitality of mulattoes is spoken of in a trustworthy work 13 as a
well-known phenomenon ; and this, although a different considera-
tion from their lessened fertility, may perhaps be advanced as
a proof of the specific distinctness of the parent races. No doubt
both animal and vegetable hybrids, when produced from extremely
distinct species, are liable to premature death ; but the parents
of mulattoes cannot be put under the category of extremely
distinct species. The common Mule, so notorious for long life
and vigour, and yet so sterile, shews how little necessary con-
nection there is in hybrids between lessened fertility and vitality ;
other analogous eases could be cited.
Even if it should hereafter bp proved that all the races of
men were perfectly fertile together, he who was inclined from
other reasons to rank them as distinct species, might with justice
argue that fertility and sterility are not safe criterions of specific
distinctness, We know that these qualities are easily affected
by changed conditions of life, or by close inter-breeding, and that
they are governed by highly complex laws, for instance, that of
the unequal fertility of converse crosses between the same two
species. With forms which must be ranked as undoubted
species, a perfect series exists from, those which are absolutely
sterile when crossed, to those which are almost or completely
vincesofthe Animal World,' Charles- the children are few and sickly,
ton, 1855, p. 44. This belief, as Mr. Reade remarks,
12 Dr. Rohifs writes to me that deserves attention, a$ white men
he found the mixed races in the have visited and resided on the Gold
Great Sahara, derived from Arabs, Coast for four hundred years, so
Berbers, and Negroes of three tribes, that the natives have had amp.V
extraordinarily fertile. On the other time to gain knowledge throug
hand, Mr. Winwood Reade informs experience.
xne that the Negroes on the Gold 13 * Military and Anthropoid
Coast, though admiring white men Statistics of American Soldiers,"
and mulattoes, have a maxim that B. A. Gould, 1869, p. 319.
mulattoes should not intermarry, as
172
The Descent of Man.
Part!
fertile. The degrees of sterility do not coincide strictly with
the degrees of difference between the parents in external structure
or habits of life. Man in many respects may be compared with
those animals which have long been domesticated, and a large
body of evidence can be advanced in favour of the Pallasian
doctrine, 14 that domestication tends to eliminate the sterility
which is so general a result of the crossing of species in a state
of nature. From these several considerations, it may be justly
> urged that the perfect fertility of the intercrossed races of man,
I if established, would not absolutely preclude us from ranking
Ithem as distinct species.
Independently of fertility, the characters presented by the off-
spring from a cross have been thought to indicate whether or not
the parent-forms ought to be ranked as species or varieties ; but
after carefully studying the evidence, I have come to the con-
clusion that no general rules of this kind can be trusted. The
ordinary result of a cross is the production of a blended or
14 'The Variation of Animals and sterile, it is scarcely possible that
Plants under Domestication,' vol. ii.
p. 109. I may here remind the
reader that the sterility of species
when crossed is not a specially-
acquired quality, but, like the in-
capacity of certain trees to be graft-
ed together, is incidental on other
acquired differences. The nature
of these differences is unknown, but
they relate more especially to the re-
productive system, and much less so
to external structure or to ordinary
differences in constitution. One
important element in the sterility
of crossed species apparently lies in
one or both having been long habi-
tuated to fixed conditions ; for we
know that changed conditions have
a special influence on the repro-
ductive system, and we have good
reason to believe (as before re-
marked) that the fluctuating ' con-
ditions of domestication tend to
eliminate that 'sterility which is so
general with species, in a natural
state, when crossed. It has else-
where been shewn by me (ibid. vol.
ii. p. 185, and ' Origin of Species'
5th edit. p. 317), that the sterility
of crossed species has not been ac-
quired through natural selection :
we can see that when two forms
have already been rendered very
their sterility should be augmented
by the preservation or survival of
the more and more sterile indi-
viduals ; for as the sterility in-
creases, fewer and fewer offspring
will be produced from which to
breed, and at last only single in-
dividuals will be produced, at the
rarest intervals. But there is even
a higher grade of sterility than
this. Both Gartner and Kolreuter
have proved that in genera of plants
including many species, a series
can be tbrmed from species which
when crossed yield fewer and fewer
seeds, to species which never pro-
duce a single seed, but yet are
affected by the pollen of the other
species, as shewn by the swelling
of the gevmen. It is here mani-
festly impossible to select the more
sterile individuals, which have al-
ready ceased to yield seeds; so that
the acme of sterility, when the
germea alone is affected, cannot
have been gained through selection.
This acme, and no doubt the other
grades of sterility, are the incidental
results of certain unknown differ-
ences in the constitution of the re-
productive system of the specie*
which are crossed,
Chap. VJL The Races of Man. 173
intermediate form ; but in certain cases some of the offspring take
closely after one parent-form, and some after the othei. This is
especially apt to occur when the parents differ in characters
which first appeared as sudden variations or monstrosities. 15 I
refer to this point, because Dr. Eohlfs informs me that he has
frequently seen in Africa the offspring of negroes crossed with
members of other races, either completely black or completely
white, or rarely piebald. On the other hand, it is notorious
that in America mulattoes commonly present an intermediate
appearance.
We have now seen that a naturalist might feel himself fully
justified in ranking the races of man as distinct species ; for ho
has found that they are distinguished by many differences in
structure and constitution, some being of importance. These
differences have, also, remained nearly constant for very long
periods of time. Our naturalist will have been in some degree
influenced by the enormous range of man, which is a great
anomaly in the class of mammals, if mankind be viewed as a
single species. He will have been struck with the distribution of
the several so-called races, which accords with that of other
undoubtedly distinct species of mammals. Finally, he might
urge that the mutual fertility of all the races has not as yet been
fully proved, and even if proved would not be an absolute proof
of their specific identity.
On the other side of the question, if our supposed naturalist
were to enquire whether the forms of man keep distinct like
ordinary species, when mingled together in large numbers in the
same country, he would immediately discover that this was by
no means the case. In Brazil he would behold an immense
mongrel population of Negroes and Portuguese ; in Chiloe, and
other parts of South America, he would behold the whole popu-
lation consisting of Indians and Spaniards blended in various
degrees. 16 In many parts of the same continent he would meet
with the most complex crosses between Negroes, Indians, and
Europeans ; and judging from the vegetable kingdom, such triple
crosses afford the severest test of the mutual fertility of the
parent-forms. In one island of the Pacific he would find a
small population of mingled Polynesian and English blood ; and
in the Fiji Archipelago a population of Polynesian and Negritos
15 * The Variation of Animals,' success and energy of the Paulistaa
&c, vol. ii. u. 92. in Brazil, who are a much crossed
id M. de Quatrefages has given race 01 Portuguese and Indians, with
(* Anthropolog. Review,' Jan. 1869, a mixture of the blood of othw
p. 22) an interesting account of the races.
174 The Descent of Man. Pirn? I.
crossed in all degrees. Many analogous cases could "be be adaed ;
for instance, in Africa. Hence the races of man are not suf-
t ficiently distinct to inhabit the same country without fusion ;
\and the absence of fusion affords the usual and best test 01
| specific distinctness.
Our naturalist would likewise be much disturbed as soon as
he perceived that the distinctive characters of all the races were
highly variable. This fact strikes every one on first beholding
the negro slaves in Brazil, who have been imported from all
parts of Africa. The same remark holds good with the
Polynesians, and with many other races. It may be doubted
whether any character can be named which is distinctive of a
race and is constant. Savages, even within the limits of the
same tribe, are not nearly so uniform in character, as has been
often asserted. Hottentot women offer certain peculiarities,
more strongly marked than those occurring in any other race,
but these are known not to be of constant occurrence. In the
several American tribes, colour and hairiness differ considerably;
as does colour to a certain degree, and the shape of the features
greatly, in the Negroes of Africa. The shape of the skull varies
much in some races ; 17 and so it is with every other character.
Now all naturalists have learnt by dearly-bought experience, how
rash it is to attempt to define species by the aid of inconstant
characters.
\But the most weighty of all the arguments against treating
the races of man as distinct species, is that they graduate into
each other, independently in many cases, as far as we can judge,
of their having intercrossed. Man has been studied more
carefully than any other animal, and yet there is the greatest
possible diversity amongst capable judges whether he should be
classed as a single species or race, or as two (Virey), as three
(Jacquinot), as four (Kant), five (Blumenbach), six (Buffon),
seven (Hunter), eight (Agassiz), eleven (Pickering), fifteen
(Bory St. Vincent), sixteen (Desmoulins), twenty-two (Morton),
sixty (Crawfurd), or as sixty-three, according to Burke. 18 This
diversity of judgment does not prove that the races ought not
to be ranked as species, but it shews that they graduate into each
17 For instance with the abori- 18 See a good discussion on this
giiies of America and Australia, subject in Waitz, * Introduct. to
Prof. Huxley says (' Transact. Inter- Anthropology/ Eng. translat. 1863,
nat. Congress of Prehist. Arch/ pp. 198-208, 227. I have taken
1868, p. 105) that the skulls of some of the above statements from
many South Germans and Swiss are H. Tuttle's * Origin and Antiquity
* as short and as broad as those of of Physical Man,* Boston, 1866, p.
* thfc 1 artars," &c. 35.
Crap. VlL The Races of Man. i?5
other, and that it is hardly possible to discover clear distinctive \
characters between them.
Every naturalist who has had the misfortune to undertake the
description of a group of highly varying organisms, has en-
countered cases (I speak after experience) precisely like that of
man ; and if of a cautious disposition, he will end by uniting all
the forms which graduate into each other, under a single
species ; for he will say to himself that he has no right to give
names to objects which he cannot define. Cases of this kind
occur in the Order which includes man, namely in certain genera
of monkeys; whilst in other genera, as in Cercopithecus, most of
the species can be determined with certainty. In the American
genus Cebus, the various forms are ranked by some naturalists
as species, by others as mere geographical races. Now if
numerous specimens of Cebus were collected from all parts of
South America, and those forms which at present appear to be
specifically distinct, were found to graduate into each other by
close steps, they would usually be ranked as mere varieties or \
races ; and this course has been followed by most naturalists
with respect to the races of man. Nevertheless, it must be
confessed that there are forms, at least in the vegetable king-
dom, 19 which we cannot avoid naming as species, but which are
connected together by numberless gradations, independently of
intercrossing.
Some naturalists have lately employed the term " sub-species"
to designate forms which possess many of the characteristics of
true species, but which hardly deserve so high a rank. Now if
we reflect on the weighty arguments above given, for raising the
races of man to the dignity of species, and the insuperable diffi-
culties on the other side in defining them, it seems that the term
"sub-species" might here be used with propriety. But from J
long habit the term "race" will perhaps always be employed. 1
The choice of terms is only so far important in that it is desirablo f
to use, as far as possible, the same terms for the same degrees of"
difference. Unfortunately this can rarely be done : for the larger
genera generally include closely-allied forms, which can be
distinguished only with much difficulty, whilst the smaller
genera within the same family include forms that are perfectly
distinct ; yet all must be ranked equally as species. So again,
species within the same large genus by no means resemble
each other to the same degree : on the contrary, some of them
19 Piof. Nageli has carefully de- has made analogous remarks on
scribed several striking cases in his some intermediate forms in the
4 Botanische Mittheilungen/ B. ii. Compos: tse of N. America,
1S66, s. 294-369. Prof. Asa Gray
I j6 The Descent of Man , Paw* I
can generally be arranged in little groups round other species^
like satellites round planets. 20
The question whether mankind consists of one or severa
species has of late years been much discussed by anthropologists,
who are divided into the two schools of monogenists and
polygenists. Those who do not admit the principle of evolution,
must look at species as separate creations, or as in some manner
as distinct entities ; and they must decide what forms of man they
will consider as species by the analogy of the method commonly
pursued in ranking other organic beings as species. But it is a
hopeless endeavour to decide this point, until some definition of
the term "species'* is generally accepted; and the definition
must not include an indeterminate element such as an act of
creation. We might as well attempt without any definition to
decide whether a certain number of houses should be called a
village, town, or city. We have a practical illustration of the
difficulty in the never-ending doubts whether many closely-allied
mammals, birds, insects, and plants, which represent each
other respectively in North America and Europe, should bo
ranked as species or geographical races ; and the like holds true
of the productions of many islands situated at some little distance
from the nearest continent.
Those naturalists, on the other hand, who admit the principle
of evolution, and this is now admitted by the majority of rising
men, will feel no doubt that all the races of man are descended
from a single primitive stock ; whether or not they may think
fit to designate the races as distinct species, for the sake of ex-
pressing their amount of difference. 21 With our domestic
animals the question whether the various races have arisen from
one or more species is somewhat different. Although it may be
admitted that all the races, as well as all the natural species
within the same genus, have sprung from the same primitive
stock, yet it is a fit subject for discussion, whether all the
domestic races of the dog, for instance, have acquired theii
present amount of difference since some one species was first
domesticated by man; or whether they owe some of their
characters to inheritance from distinct species, which had
already been differentiated in a state of nature. With man no
such question can arise, for he cannot be said to have been
domesticated at any particular period.
During an early stage in the divergence of the races of man
70 * Origin of Species/ 5th edit, in the 'Fortnightly Review/ 1885,
J\ 68. * p. 275.
« See Pzot Hux1gy to this eSbet
Chap. VII. The Races of. Man. 177
from a common stock, the differences between the races and
their number must have been small; consequently as far as
their distinguishing characters are concerned, they then had less
claim to rank as distinct species than the existing so-called races.
Nevertheless, so arbitrary is the term of species, that such early
races would perhaps have been ranked by some naturab'sts as
distinct species, if their differences, although extremely slight,
had been more constant than they are at present, and had not
graduated into each other.
It is however possible, though far from probable, that the
early progenitors of man might formerly have diverged much in
character, until they became more unlike each other than any
now existing races; but that subsequently, as suggested by
Vogt, 22 they converged in character. When man selects the off-
spring of two distinct species for the same object, he sometimes
induces a considerable amount of convergence, as far as general
appearance is concerned. This is the case, as shewn by Von
Nathusius, 23 with the improved breeds of the pig, which are
descended from two distinct species; and in a less marked
manner with the improved breeds of cattle. A great anatomist,
Gratiolet, maintains that the anthropomorphous apes do not
form a natural sub-group; but that the orang is a highly
developed gibbon or semnopithecus, the chimpanzee a highly
developed macacus, and the gorilla a highly developed mandrill.
If this conclusion, which rests almost exclusively on brain-
characters, be admitted, we should have a case of convergence
at least in external characters, for the anthropomorphous apes
are certainly more like each other in many points, than they are
to other apes. All analogical resemblances, as of a whale to a
fish, may indeed be said to be cases of convergence ; but this
term has never been applied to superficial and adaptive resem-
blances. It would, however, be extremely rash to attribute to
convergence close similarity of character in many points of
structure amongst the modified descendants of widely distinct
beings. The form of a crystal is determined solely by the mole-
cular forces, and it is not surprising that dissimilar substances
should sometimes assume the same form; but with organic
beings we should bear in mind that the form of each depends on
an infinity of complex relations, namely on variations, due to
causes far too intricate to be followed, — on the nature of the
variations preserved, these depending on the physicial condi-
22 * Lectures on Man,* Eng. trans- schichtc, &c, Schweineschadel,
lat. 1864, p. 468. 1864, s. 104. With respect to catt!*,
26 'Die Racen des Schweines,' see M. de Quatrefages, 'Unite' de
I860, s, 46 'Vorstadien fur Ge- l'EspeceHumaine/lSei, p. 119
1 7$ The Descent of Man. Part I.
tions. and still more on the surrounding organisms which com-
pete with each,— and lastly, on inheritance (in itself a fluctuating
element) from innumerable progenitors, all of which have had
their forms determined through equally complex relations. It
appears incredible that the modified descendants of two organ •
isms, if these differed from each other in a marked manner,
should ever afterwards converge so closely as to lead to a near
approach to identity throughout their whole organisation. In
the case of the convergent races of pigs above referred to, evi-
dence of their descent from two primitive stocks is, according to
Von Nathusius, still plainly retained, in certain bones of their
skulls. If the races of man had descended, as is supposed by
some naturalists, from two or more species, which differed from
each other as much, or nearly as much, as does the orang from
the gorilla, it can hardly be doubted that marked differences in
the structure of certain bones would still be discoverable in man
as he now exists.
. Although the existing races of man differ in many respects, as
/in colour, hair, shape of skull, proportions of the body, &c, yet
j if their whole structure be taken into consideration they are
' found to resemble each other closely in a multitude of points.
Many of these are of so unimportant or of so singular a nature,
that it is extremely improbable that they should have been inde-
pendently acquired by aboriginally distinct species or races.
The same remark holds good with equal or greater force with
respect to the numerous points of mental similarity between the
most distinct races of man. The American aborigines, Negroes
and Europeans are as different from each other in mind as any
three races that can be named; yet I was incessantly struck,
whilst living with the Fuegians on board the " Beagle," with the
many little traits of character, shewing how similar their minds
were to ours; and so it was with a full-blooded negro with whom
I happened once to be intimate.
He who will read Mr. Tylor/s and Sir J. Lubbock's interesting
works 24 can hardly fail to be deeply impressed with the close
similarity between the men of all races in tastes, dispositions and
habits. This is shewn by the pleasure which they all take in
dancing, rude music, acting, painting, tattooing, and otherwise
decorating themselves ; in their mutual comprehension of gesture-
language, by the same expression in their features, and by the
same inarticulate cries, when excited by the same emotions.
This similarity, or rather identity, is striking, when contrasted
** Tylor's * Early History of Man- language, see p. 54. Lubbock'a
kind/ 1865 : with respect to gestnre- ' Prehistoric .Times,* 2nd edit. 1 86&
Chap. VII. The Races of Man. 179
with the different expressions and cries made by distinct species
of monkeys. There is good evidence that the art of shooting
with bows and arrows has not been handed down from any
common progenitor of mankind, yet as Westropp and Nilsson
have remarked, 25 the stone arrow-heads, brought from the most
distant parts of the world, and manufactured at the most remote
periods, are almost identical ; and this fM -- ^n ™ily ha mw^intflfl l
for bv_ the various races having similar inventive or / mental ! \
powers. The same observation has been made by archaeologists 20
witETrespect to certain widely-prevalent ornaments, such as zig-
zags, &c. ; and with respect to various simple beliefs and cus-
toms, such as the burying of the dead under megalithic struc-
tures. I remember observing in South America, 27 that there, as
in so many other parts of the world, men have generally chosen
the summits of lofty hills, to throw up piles of stones, either as
a record of some remarkable event, or for burying their dead.
Now when naturalists observe a close agreement in numerous
small details of habits, tastes, and dispositions between two or
more domestic races, or between Nearly-allied natural forms,
they use this fact as an argument that they are descended from a
common progenitor who was thus endowed ; and consequently
that all should be classed under the same species. The same
argument may be applied with much force to the races of man.
As it is improbable that the numerous and unimportant points
of resemblance between the several races of man in bodily struct
ture and mental faculties (I do not here refer to similar customs)
should all have been independently acquired, they must havo been
inherited from progenitors who had these same characters. We
thus gain some insight into the early state of man, before he had
spread step by step over the face of the earth. The spreading
of man to regions widely separated by the sea, no doubt, pre-
ceded any great amount of divergence of character in the several
races ; for otherwise we should sometimes meet with the same
race in distinct continents; and this is never the case. Sir J.
Lubbock, after comparing the arts now practised by savages in
all parts of the world, specifies those which man could not have
known, when he first wandered from his original birth-place;
for if once learnt they would never have been forgotten. 28 He
25 'On Analogous Forms of Im- 'Journal of Ethnological Soc.' as
plements/ in ' Memoirs of Anthropo- given in ' Scientific Opinion/ June
log. Soc./ by H. M. Westropp. « The 2nd, 1869, p. 3.
Primitive Inhabitants of Scaadi- 2r 'Journal of Researches: Voyags
navia/ Eng. translat. edited by Sir of the "Beagle,"' p. 46.
J. Lubbock, 1868, p. 104. 28 ' Prehistoric Times/ 1869, p,
*• Westropp, ' On Cromlechs/ &c, 574.
N 2
180 The Descent of Man. Part L
thus shews that " the spear, which is but a development of the
•' knife-point, and the club, which is but a long hammer, are the
<l only things left." He admits, however, that the art of making
fire probably had been already discovered, for it is common to
all the races now existing, and was known to the ancient cave-
inhabitants of Europe. Perhaps the art of making rude canoes
or rafts was likewise known; but as man existed at a remote
epoch, when the land in many places stood at a very different
level to what it does now, he would have been able, without the
j aid of canoes, to have spread widely. Sir J. Lubbock further
X remarks how improbable it is that our earliest ancestors could
\ have " counted as high as ten, considering that so many races
V'now in existence cannot get beyond four." Nevertheless, at
this early period, the intellectual and social faculties of man
could hardly have been inferior in any extreme degree to those
possessed at present by the lowest savages ; otherwise primeval
man could not have been so eminently successful in the struggle
for life, as proved by his early and. wide diffusion.
From the fundamental differences between certain languages,
some philologists have inferred that when man first became
widely diffused, he was not a speaking animal ; but it may be
suspected that languages, far less perfect than any now spoken,
aided by gestures, might have been used, and yet have left no
traces on subsequent and more highly-developed tongues. With-
out the use of some language, however imperfect, it appears
doubtful whether man's intellect could have risen to the
standard implied by his dominant position at an early period.
Whether primeval man, when he possessed but few arts, and
those of the rudest kind, and when his power of language was
extremely imperfect, would have deserved to be called man, must
depend on the definition which we employ. In a series of forms
graduating insensibly from some ape-like creature to man as he
now exists, it would be impossible to fix on any definite point when
the term " man " ought to be used. But this is a matter of very
little importance. So again, it is almost a matter of indifference
whether the so-called races of man are thus designated, or are
ranked as species or sub-species ; but the latter term appears the
more appropriate. Finally, we may conclude that when the
principle of evolution is generally accepted, as it surely will be
before long, the dispute between the monogenists and the poly-
genists will die a silent and unobserved death.
One other question ought not to be passed over without notice,
namely, whether, as is sometimes assumed, each sub-species or
race of man has sprung from a single pair of progenitors. With
Chap. VII. Tfie Extinction of Races. I Si
our domestic animals a new race can readily be formed by care-
fully matching the varying offspring from a single pair, or even
from a single individual possessing some new character; but
most of our races have been formed, not intentionally from a
selected pair, but unconsciously by the preservation of many in-
dividuals which have varied, however slightly, in some useful or
desired manner. If in one country stronger and heavier horses,
and in another country lighter and fleeter ones, were habitually
preferred, we may feel sure that two distinct sub-breeds would
be produced in the course of time, without any one pair having
been separated and bred from, in either country. Many races \
have been thus formed, and their manner of formation is closely »
analogous to that of natural species. We know, also, that the
horses taken to the Falkland Islands have, during successive
generations, become smaller and weaker, whilst those which have
run wild on the Pampas have acquired larger and coarser heads;
and such changes are manifestly due, not to any one pair, but to
all the individuals having been subjected to the same conditions,
aided, perhaps, by the principle of reversion. The new sub-
breeds in such cases are not descended from any single pair, but
from many individuals which have varied in different degrees,
but in the same general manner ; and we may conclude that the
races of man have been similarly produced, the modifications
being either the direct result of exposure to different conditions,
or the indirect result of some form of selection. But to this:
latter subject we shall presently return.
On the Extinction of the Races of Man, — The partial or complete
extinction of many races and sub-races of man is historically
known. Humboldt saw in South America a parrot which was
the sole living creature that could speak a word of the language
of a lost tribe. Ancient monuments and stone implements
found in all parts of the world, about which no tradition has been
preserved by the present inhabitants, indicate much extinction.
Some small and broken tribes, remnants of former races, still
survive in isolated and generally mountainous districts. In
Europe the ancient races were all, according to Schaaffhausen, 29
" lower in the scale than the rudesfc living savages ;" they must
therefore have differed, to a certain extent, from any existing
race. The "remains described by Professor Broca from Les Eyzies,
though they unfortunately appear to have belonged to a single
family, indicate a race with a most singular combination of low
or simious, and of high characteristics. This race is " entirely
88 Translation in Anthropological Review, Oct. 1868, p. 431
i82 Tne Descent of Man. Pabt I.
" different from any other, ancient or modern, that we have ever
"heard of." 80 It differed, therefore, from the quaternary race of
the caverns of Belgium.
i Man can long resist conditions which appear extremely un-
| favourable for his existence. 81 He has long lived in the extreme
regions of the North, with no wood for his canoes or implements,
and with only blubber as fuel, and melted snow as drink. In
the southern extremity of America the Fuegians survive with-
out the protection of clothes, or of any building worthy to be
called a hovel. In South Africa the aborigines wander over arid
plains, where dangerous beasts abound. Man can withstand the
deadly influence of the Terai at the foot of the Himalaya, and
the pestilential shores of tropical Africa.
i Extinction follows chiefly from the competition of tribe with
I tribe, and race with race. Various checks are always in action,
serving to keep down the numbers of each savage tribe, — such
as periodical famines, nomadic habits and the consequent deaths
of infants, prolonged suckling, wars, accidents, sickness, licen-
tiousness, the stealing of women, infanticide, and especially
lessened fertility. If any one of these checks increases in power,
even slightly, the tribe thus affected tends to decrease ; and
when of two adjoining tribes one becomes less numerous and less
powerful than the other, the contest is soon settled by war,
slaughter, cannibalism, slavery, and absorption. Even when a
weaker tribe is not thus abruptly swept away, if it once begins
to decrease, it generally goes on decreasing until it becomes
extinct. 32
When civilised nations come into contact with barbarians the
struggle is short, except where a deadly climate gives its aid to
the native race. Of the causes which lead to the victory of
civilised nations, some are plain and simple, others complex and
obscure. We can see that the cultivation of the land will
be fatal in many ways to savages, for they cannot, or will not,
change their habits. New diseases and vices have in some cases
proved highly destructive ; and it appears that a new disease
often causes much death, until those who are most susceptible
to its destructive influence are gradually weeded out j 83 and so it
may be with the evil effects from spirituous liquors, as well as
with the unconquerably strong taste for them shewn by so many
80 * Transact. Internat. Congress terben der Natnrvolker/ 1868, s. 82.
\i Prehistoric Arch/ 1868, pp. 172- 32 Gerland (ibid. s. 12) gives facts
175. See also Br oca (translation) in support of this statement,
in * Anthropological Review/ Oct. 33 See remarks to this effect in
1868, p. 410. Sir H. Holland's ' Medical Notes and
31 Dr. Gerlan.l < Ueber das Anss- Reflections/ 1839, p. 390.
ChaivVTL TJie Extinction of Races. 183
savages. It further appears, mysterious as is the fact ihat
the first meeting of distinct and separated people generates
disease. 34 Mr. Sproat, who in Vancouver Island closely attended
to the subject of extinction, believed that changed habits of life,
consequent on the advent of Europeans, induces much ill health,
He lays, also, great stress on the apparently trifling cause that
the natives become '" bewildered and dull by the new life around
" them ; they lose the motives for exertion, and get no ^w ones
"in their place." 36
The grade of their civilisation seems to be a most important
element in the success of competing nations. A few centuries
ago Europe feared the inroads of Eastern barbarians ; now any
such fear would be ridiculous. It is a more curious fact, as
Mr. Bagehot has remarked, that savages did not formerly waste
away before the classical nations, as they now do before modern
civilised nations; had they done so, the old moralists would
have mused over the event ; but there is no lament in any writer
of that period over the perishing barbarians. 36 The most po-
tent of all the causes of extinction, appears in many cases to be
lessened fertility and ill-health, especially amongst the children,
arising from changed conditions of life, notwithstanding that the
new conditions may not be injurious in themselves. I am much
indebted to Mr. H. H. Howorth for having called my attention to
this subject, and for having given me information respecting it.
I have collected the following cases.
When Tasmania was first colonised the natives were roughly
estimated by some at 7000 and by others at 20,000. Their
number was soon greatly reduced, chiefly by fighting with the
English and with each other. After the famous hunt by all the
colonists, when the remaining natives delivered themselves up
to the government, they consisted only of 120 individuals, 87
who were in 1832 transported to Flinders Island. This island,
situated between Tasmania and Australia, is forty miles long,
and from twelve to eighteen miles broad: it seems healthy,
and the natives were well treated. Nevertheless, they suifered
greatly in health. In 1834 they consisted (Bonwick, p. 250) of
forty-seven adult males, forty-eight adult females, and sixteen
children, or in all of 111 souls. In 1835 only one hundred were left.
* 4 I have collected (' Journal of Savage Life/ 1868, p. 284.
Researches, Voyage of the" Beagle," ' S6 Bagehot, 'Physics and Poli-
p. 435) a good many cases bearing tics,' * Fortnightly Review/ April
on this subject; see also Gerland, 1, 1868, p. 455.
ibid. s. 8. Poeppig speaks of the 37 Ail the statements here given
"breath of civilisation as poisonous are taken from * The last of th
" to savages." Tasmanians/ by J. Bonwick, 1870,
85 Sproat, ' Scenes and Stndies ol
184 The Descent of Man. Part i.
As they continued rapidly to decrease, and as they themselves
thought that they should not perish so quickly elsewhere, they were
removed in 1847 to Oyster Cove in the southern part of Tasmania.
They then consisted (Dec. 20th, 1847) of fourteen men, twenty-
two women and ten children. 38 But the change of site did no good.
Disease and death still pursued them, and in 1864 one man (who
died in 1869), and three elderly women alone survived. The
infertility of the women is even a more remarkable fact than
the liability of all to ill-health and death. At the time when
only nine women were left at Oyster Cove, they told Mr. Bonwick
(p. 386), that only two had ever borne children : and these two
had together produced only three children !
With respect to the cause of this extraordinary state of things,
Dr. Story remarks that death followed the attempts to civilise
the natives. " If left to themselves to roam as they were wont
" and undisturbed, they would have reared more children, and
''there would have been less mortality." Another careful
observer of the natives, Mr. Davis, remarks, " The births have
" been few and the deaths numerous. This may have been in a
" great measure owing to their change of living and food ; but
" more so to their banishment from the mainland of Van Diemen's
"Land, and consequent depression of spirits" (Bonwick, pp.
388, 390).
Similar facts have been observed in two widely different
parts of Australia. The celebrated explorer, Mr. Gregory, told
Mr. Bonwick, that in Queensland "the want of reproduction
"was being already felt with the blacks, even in the most
"recently settled parts, and that decay would set in." Of
thirteen aborigines from Shark's Bay who visited Murchison
Biver, twelve died of consumption within three months. 39
The decrease of the Maories of New Zealand has been carefully
investigated by Mr. Fenton, in an admirable Beport, from which
all the following statements, with one exception, are taken. 40
The decrease in number since 1830 is admitted by every one,
including the natives themselves, and is still steadily progress-
ing. Although it has hitherto been found impossible to take an
actual census of the natives, their numbers were carefully
estimated by residents in many districts. The result seems
trustworthy, and shows that during the fourteen years, previous
38 This is tho statement of the 1870, p. 90 ; and the 'Last of the
Governor of Tasmania, Sir W. Deni- Tasmanians/ 1870, p. 386.
son, * Varieties of Vice-Regal Life/ *° Observations on the Aboriginal
1870, vol. i. p. 67, Inhabitants of New Zealand/ pub*
*• For these cases, see Bonwick's lished by the Government, 1859.
'Daily Life of the Tasmanians/
Chap. Til. The Extinction of Races. 185
to 1858, the deerease was 19.42 per cent. Some of the tribes,
thus carefully examined, lived above a hundred miles apart,
some on the coast, some inland ; and their means of subsistence
and habits differed to a certain extent (p. 28). The total
number in 1858 was believed to be 53,700, and in 1872, after a
second interval of fourteen years, another census was taken,
and the number is given as only 36,359, shewing a decrease o\
3229 per cent.! 41 Mr. Fenton, after shewing in detail the in-
sufficiency of the various causes, usually assigned in explana-
tion of this extraordinary decrease, such as new diseases, the
profligacy of the women, drunkenness, wars, &c, concludes on
weighty grounds that it depends chiefly on the unproductiveness
of the women, and on the extraordinary mortality of the young
children (pp. 31, 34). In proof of this he shews (p. 33) that in
1844 there was one non-adult for every 2'57 adults; whereas in
1858 there was only one non-adult for every 3*27 adults. The
mortality of the adults is also great. He adduces as a further
cause of the decrease the inequality of the sexes ; for fewer females
are born than males. To this latter point, depending perhaps
on a widely distinct cause, I shall return in a future chapter.
Mr. Fenton contrasts with astonishment the decrease in New
Zealand with the increase in Ireland ; countries not very dis-
similar in climate, and where the inhabitants now follow nearly
similar habits. The Maories themselves (p. 35) «' attribute their
'* decadence, in some measure, to the introduction of new food
" and clothing, and the attendant change of habits ;" and it will
be seen, when we consider the influence of changed conditions
on fertility, that they are probably right. The diminution began
between the years 1830 and 1840 ; and Mr. Fenton shews (p. 40)
that about 1830, the art of manufacturing putrid corn (maize),
by long steeping in water, was discovered and largely practised ;
and this proves that a change of habits was beginning amongst
the natives, even when New Zealand was only thinly inhabited
by Europeans. When I visited the Bay of Islands in 1835,
the dress and food of the inhabitants had already been much
modified: they raised potatoes, maize, and other agricultural
produce, and exchanged them for English manufactured goods
and tobacco.
It is evident from many statements in the life of Bishop
Patteson, 42 that the Mclanesians of the New Iletrides and
neighbouring archipelagoes, suffered to an extraordinary degree
in health, and perished in large numbers, when they were
41 'New Zealand,' by Alex. Kc-n- C. M. Younge, 1874; see mort
nedy, 1873, p. 47. especially vol. i. p. 530,
« * Life of J. C. Patteson/ by
186
The Descent, of Man.
Part I.
removed to New Zealand, Norfolk Island, and other salubrious
places, in order to be educated as missionaries.
The decrease of the native population of the Sandwich Islands
is as notorious as that of New Zealand. It has been roughly
estimated by those best capable of judging, that when Cook
discovered the Islands in 1779, the population amounted to
about 800,000. According to a loose census in 1823, the
numbers then were 142,050. In 1832, and at several subsequent
periods, an accurate census was officially taken, but I have
been able to obtain only the following returns :
Year.
1832
1336
1853
1800
1866
1872
Native Population.
(Except during 1832
and 1836, when the
few foreigners in the
islands were included).
130,313.
108,579{
71,019.
67,084;
58,765:
51,531
Annual rate of decrease
per cent., assuming it
to have been uniform be-
tween the successive cen-
suses ; these censuses be-
ing taken at irregular
intervals.
4-46
2-47
0-81
2*18
2-17
We here see that in the interval of forty years, between 1832 and
1872, the population has decreased no less than sixty-eight per
cent. ! This has been attributed by most writers to the profligacy
of the women, to former bloody wars, and to the severe labour
imposed on conquered tribes and to newly introduced diseases,
which have been on several occasions extremely destructive. No
doubt these and other such causes have been highly efficient,
and may account for the extraordinary rate of decrease between
the years 1832 and 1836 ; but the most potent of all the causes
seems to be lessened fertility. According to Dr. Ruschenberger
of the UJS. Navy, who visited these islands between 1835 and
1837, in one district of Hawaii, only twenty-five men out of 1134,
and in another district only ten out of 637, had a family with as
many as three children. Of eighty married women, only thirty-
nine had ever borne children ; and " the official report gives an
*' average of half a child to each married couple in the whole
Chap. VII. The Extinction of Races. 187
a island." This is almost exactly the same average as with the
Tasmanians at Oyster Cove. Jarves, who published his History
in 1843, says that " families who have three children are freed fjom
*' all taxes ; those having more, are rewarded by gifts of land and
" other encouragements." This unparalleled enactment by the
government well shews how infertile the race had become. The
Rev. A. Bishop stated in the Hawaiian ' Spectator' in 1839, that a
large proportion of the children die at early ages, and Bishop
Staley informs me that this is still the case, just as in New
Zealand. This has been attributed to the neglect of the children
by the women, but it is probably in large part due to innate weak-
ness of constitution in the children, in relation to the lessened
fertility of their parents. There is, moreover, a further resem-^
blance to the case of New Zealand, in the fact that there is a
large excess of male over female births : the census of 1872
gives 31,650 males to 25,24=7 females of all ages, that is 125*36
males for every 100 females ; whereas in all civilised countries
the females exceed the males. No doubt the profligacy of the
women may in part account for their small fertility ; but their
changed habits of life is a much more probable cause, and which
will at the same time account for' the increased mortality,
especially of the children. The islands were visited by Cook in
1779, by Vancouver in 1794, and often subsequently by whalers.
In 1819 missionaries arrived, and found that idolatry had been
already abolished, and other changes effected by the king. After
this period there was a rapid change in almost all the habits of
life of the natives, and they soon became " the most civilised of
" the Pacific Islanders." One of my informants, Mr. Coan, who
was born on the islands, remarks that the natives have undergone
a greater change in their habits of life in the course of fifty years
than Englishman during a thousand years. From information
received from Bishop Staley, it does not appear that the
poorer classes have ever much changed their diet, although
many new kinds of fruit have been introduced, and the sugar-
cane is in universal use. Owing, however, to their passion for
imitating Europeans, they altered their manner of dressing at
an early period, and the use of alcoholic drinks became very
general. Although these changes appear inconsiderable, I can
well believe, from what is known with respect to animals, that
they might suffice to lessen the fertility of the natives. 43
43 The foregoing statements are Islands/ 1851, p. 277. Ruschen-
taken chiefly from the following berger is quoted by Bonwick, * Last
works : * Jarves' History of the of the Tasmanians/ 1870, p. 378.
Hawaiian Islands/ 1843, p. 400-407. Bishop is quoted by Sir E. Belcher,
Cheever, * Life in the Sandwich *Voyag« Round the World/ 1843,
1 88 The Descent of Man. Pabt L
Lastly, Mr. Macnamara states 44 that the low and degraded
inhabitants of the Andaman Islands, on the eastern side oi" the
Gulf of Bengal, are "eminently susceptible to any change of
" climate : in fact, take them away from their island homes, and
" they are almost certain to die, and that independently of diet
" or extraneous influences." Be further states that the inhabit-
ants of the Valley of Nepal, which is extremely hot in summer,
and also the various hill-tribes of India, suffer from dysentery
and fever when on the plains ; and they die if they attempt to
pass the whole year there.
We thus see that many of the wilder races of man are apt to
suffer much in health when subjected to changed conditions
or habits of life, and not exclusively from being transported to
a new climate. Mere alterations in habits, which do not appear
injurious in themselves, seem to have this same effect ; and in
several cases the children are particularly liable to suffer. It
has often been said, as Mr. Macnamara remarks, that man can
resist with impunity the greatest diversities of climate and other
changes; but this is true only of the civilised races. Man in
his wild condition seems to be in this respect almost as sus-
ceptible as his nearest allies, the anthropoid apes, which have
never yet survived long, when removed from their native
I country.
Lessened fertility from changed conditions, as in the case of the
Tasmanians, Maories, Sandwich Islanders, and apparently the
Australians, is still more interesting than their liability to
ill-health and death; for even a slight degrco of infertility,
combined with those other causes which tend to check the
increase of every population, would sooner or later lead to
extinction. The diminution of fertility may be explained in
some cases by the profligacy of the women (as until lately with
the Tahitians), but Mr. Fenton has shewn that this explanation
by no means suflices with the New Zealanders, nor does it with
the Tasmanians.
In the paper above quoted, Mr. Macnamara gives reasons for
believing that the inhabitants of districts subject to malaria are
apt to be sterile ; but this cannot apply in several of the above
cases. Some writers have suggested that the aborigines of
islands have suffered in fertility and health from long continued
vol. i., p. 272. I owe the census of of the above-named works. I have
the several years to the kindness of omitted the census for 1850, as i
Mr. Coan, at the request of Dr. You- have seen two widely different nun>
mans of New York ; and in most bers given.
cases I have compaiea the Youmans 4 * *The Indian Medical Gazette,
figures with those given in several Nov. 1, 1871, p, 240.
Chap. VII. TIu Extinction of Races. 189
inter-breeding ; but in the above cases infertility has coincided
too closely with the arrival of Europeans for us to admit this
explanation. Nor have we at present any reason to believe
that man is highly sensitive to the evil effects of inter-breeding,
especially in areas so large as New Zealand, and the Sandwich
archipelago with its diversified stations. On the contrary, it is
known that the present inhabitants of Norfolk Island are nearly
all cousins or near relations, as are the Todas in India, and the
inhabitants of some of the Western Islands of Scotland; and
yet they seem not to have suffered in fertility. 46
A much more probable view is suggested by the analogy of
the lower animals. The reproductive system can be shewn to be
susceptible to an extraordinary degree (though why we know
not) to changed conditions of life *, and this susceptibility leads
both to beneficial and to evil results. A large collection of facts
on this subject is given in chap, xviii. of vol. ii. of my ' Variation
of Animals and Plants under Domestication/ 1 can here give only
the briefest abstract; and every one interested in the subject
may consult the above work. Very slight changes increase the
health, vigour and fertility of most or all organic beings,
whilst other changes are known to render a large number of
animals sterile. One of the most familiar cases, is that of tamed
elephants not breeding in India; though they often breed in
Ava, where the females are allowed to roam about the forests to
some extent, and are thus placed under more natural conditions.
The case of various American monkeys, both sexes of which
have been kept for many years together in their own countries,
and yet have very rarely or never bred, is a more apposite in-
stance, because of their relationship to man. It is remarkable
how slight a change in the conditions often induces sterility in a
wild animal when captured ; and this is the more strange as all
our domesticated animals have become more fertile than they
were in a state of nature ; and some of them can resist the
most unnatural conditions with undiminished fertility. 46 Certain
groups of animals are much more liable than others to be
affected by captivity ; and generally all the species of the same
group are affected in the same manner. But sometimes a single
species in a group is rendered sterile, whilst the others are not
bo ; on the other hand, a single species may retain its fertility
45 On the close relationship of the Scotland, Dr. Mitchell, * Edinburgh
Norfolk Islanders, see Sir W. Deni- Medical Journal,' March to June,
son, * Varieties of Vice-Regal Life/ 1865.
vol. i. 1870, p. 410. For the Todas, 4S For the evidence on this head,
see CoL Marshall's work, 1873, p. see 'Variation of Animals* &c,
110. For the Western Islands rtf vol, ii. p. Ill,
100 Tfte Descent cf Man. Part I.
whilst most of the others fail to breed. The males and females
of some species when confined, or when allowed to live almost,
but not quite free, in their native country, never unite ; others
thus circumstanced frequently unite but never produce offspring ;
others again produce some offspring, but fewer than in a state
of nature; and as bearing on the above cases of man, it is
important to remark that the young are apt to be weak and
sickly, or malformed, and to perish at an early age.
Seeing how general is this law of the susceptibility of the
reproductive system to changed conditions of life, and that it
holds good with our nearest allies, the Quadrumana, I can
hardly doubt that it applies to man in his primeval state. Hence
if savages of any race are induced suddenly to change their
habits of life, they become more or less sterile, and their young
offspring suffer in health, in the same manner and from the same
cause, as do the elephant and hunting-leopard in India, many
monkeys in America, and a host of animals of all kinds, on removal
from their natural conditions.
We can see why it is that aborigines, who have long inha-
bited islands, and who must have been long exposed to nearly
uniform conditions, should be specially affected by any change
in their habits, as seems to be the case. Civilised races can
certainly resist changes of all kinds far better than savages;
and in this respect they resemble domesticated animals, for
though the latter sometimes suffer in health (for instance
European dogs in India), yet they are rarely rendered sterile,
though a few such instances have been recorded. 47 The
immunity of civilised races and domesticated animals is
probably due to their having been subjected to a greater extent,
and therefore having grown somewhat more accustomed, to
diversified or varying conditions, than the majority of wild
animals; and to their having formerly immigrated or been
carried from country to country, and to different families or
sub-races having inter-crossed. It appears that a cross with
civilised races at once gives to an aboriginal race an immunity
from the evil consequences of changed conditions. Thus the
crossed offspring from the Tahitians and English, when settled
in Pitcairn Island, increased so rapidly that the island was soon
overstocked ; and in June 1856 they were removed to Norfolk
Island. They then consisted of 60 married persons and 134
children, making a total of 194. Here they likewise in-
creased so rapidly, that although sixteen of them returned to Pit-
cairn Island in 1859, they numbered in January 1868, 300 souls;
« 'Variation of Animals,' &;., vol. iL, p Ifi.
Chap* VII. The Extinction of Races. 191
the males and females being in exactly equal numbers. 'What a
contrast does this case present with that of the Tasmanians ;
the Norfolk Islanders increased in only twelve and a half years
from 194 to 300; whereas the Tasmanians decreased during
fifteen years from 120 to 46, of which latter number only ten
were children. 48
So again in the interval between the census of 1866 and 1872
the natives of full blood in the Sandwich Islands decreased by
8081, whilst the half-castes, who are believed to be healthier in-
creased by 847 ; but I do not know whether the latter number
includes theroffspring from the half-castes, or only the half-castes
of the first generation.
The cases which I have here given all relate to aborigines,
who have been subjected to new conditions as the result of the
immigration of civilised men. But sterility and ill-health would
probably follow, if savages were compelled by any cause, such
as the inroad of a conquering tribe, to desert their homos and
to change their habits. It is an interesting circumstance that
the chief check to wild animals becoming domesticated, which
implies the power of their breeding freely when first captured,
and one chief check to wild men, when brought into contact
with civilisation, surviving to form a civilised race, is the same,
namely, sterility from changed conditions of life.
Finally, although the gradual decrease and ultimate extinction
of the races of man is a highly complex problem, depending on
many causes which differ in different places and at different
times ; it is the same problem as that presented by the extinc-
tion of one of the higher animals — of the fossil horse, for in-
stance, which disappeared from South America, soon afterwards
to be replaced, Within the same districts, by countless troops . y^
of the Spanish horse. The New Zealander seems conscious of-"-*""'
this parallelism, for he compares his future fate with that of jP
the native rat now almost exterminated by the European rat. w Kf f \
Though the difficulty is great to our imagination, and really v #» c %
great, if we wish to ascertain the precise causes and their \y J
manner of action, it ought not to be so to our reason, as long as ^ f *\,
we keep steadily in mind that the increase of each species and
each race is constantly checked in various ways; so that if any ^
new check, even a slight one, be superadded, the race will surely \ K
decrease in number; and decreasing numbers will sooner- or
48 These details are taken from May 29th, 1863. The following
*The Mutineers of the " Bounty," * statements about the Sandwich Is-
by Lady Belcher, 1870; and from landers are from the < Honolulu
* Pitcaim Island,' ordered to be Gazette,' and from Mr. Coan.
piinted by the House of Commons,
y
192 The Descent of Man. Past 1
later lead to extinction ; the end, in most cases, being promptly
determined by the inroads of conquering tribes.
* On the Formation of the Races of Man. — In some cases tho
I crossing of distinct races has led to the formation of a new race.
The singular fact that Europeans and Hindoos, who belong to
the same Aryan stock, and speak a language fundamentally the
same, differ widely in appearance, whilst Europeans differ but
little from Jews, who belong to the Semitic stock, and speak
quite another language, has been accounted for by Broca, 49
through certain Aryan branches having been largely crossed
by indigenous tribes during their wide diffusion. When two
u races in close contact cross, the first result is a heterogeneous
* mixture : thus Mr. Hunter, in describing the Santali or hill-tribes
of India, says that hundreds of imperceptible gradations may be
traced " from the black, squat tribes of the mountains to the tall
" olive-coloured Brahman, with his intellectual brow, calm nyes,
"and high but narrow head;" so that it is necessary in courts
of justice to ask the witnesses whether they are Santalis or
Hindoos. 60 Whether a heterogeneous people, such as the inhabi-
tants of some of the Polynesian islands, formed by the crossing
of two distinct races, with few or no pure members left, would
ever become homogeneous, is not known from direct evidence.
But as with our domesticated animals, a cross-breed can certainly
/ be fixed and made uniform by careful selection 51 in the course of
a few generations, we may infer that the free intercrossing of a
heterogeneous mixture during a long descent would supply the
place of selection, and overcome any tendency to reversion ; so
that the crossed race would ultimately become homogeneous,
though it might not partake in an equal degree of the characters
* of the two parent-races.
Of all the differences between the races of man, the colour of
the skin is the most conspicuous and one of the best marked. Ii
was formerly thought that differences of this kind could be
accounted for by long exposure to different climates; but
Tallas first shewed that this is not tenable, and he has since been
followed by almost all anthropologists. 52 This view has been
rejected chiefly because the distribution of tho variously
coloured races, most of whom must have long inhabited thei*
4 ^ ' On Anthropology/ transla- 5i PalJas, ' Act. Acad. St. Peters-
ticn * Anthropolog. Review,' Jan. burg/ 1780, part ii. p. 69. He was
1368, p. 38. followed by Rudolphi, in his « Bey-
50 i The Annals of Rural Bengal/ trage zur Anthropologic/ 1812.
j8fi8, p. 134. An excellent summary of the evi-
51 ' The Variation of Animals and dence is given by Godi on, ' De
Plants under Domestication/ vol. ii. PEspece/ 1859, vol. ii. p. 246, &c.
p. ys
4
Chai\ VII. The Formation of Races. 193
present homes, does not coincide with corresponding differenced
of climate. Some little weight may be given to stich cases as
that of the Dutch families, who, as we hear on excellent autho-
rity, 53 have not undergone the least change of colour after
residing for three centuries in South Africa. An argument on
the same side may likewise be drawn from the uniform appear-
ance in various parts of the world of gipsies and Jews, though
the uniformity of the latter has been somewhat exaggerated. 64
A very damp or a very dry atmosphere has been supposed to be
more influential in modifying the colour of the skin than mere
heat ; but as D'Orbigny in South America, and Livingstone in
Africa, arrived at diametrically opposite conclusions with respect
to dampness and dryness, any conclusion on this head must bo
considered as very doubtful. 65
Various facts, which I have given elsewhere, prove that the
colour of the skin and hair is sometimes correlated in a surpris-
ing manner with a complete immunity from the action of certain
vegetable poisons, and from the attacks of certain parasites.
Hence it occurred to me, that negroes and other dark races
might have acquired their dark tints by the darker individuals
escaping from the deadly influence of the miasma of their
native countries, during a long series of generations.
I afterwards found that this same idea had long ago occurred
to Dr. Wells. 56 It has long been known that negroes, and even*
mulattoes, are almost completely exempt from the yellow -fever, \
so destructive in tropical America. 37 They likewise escape to a
large extent the fatal intermittent fevers, that prevail along at
least 2600 miles of the shores of Africa, and which annually
cause one-fifth of the white settlers to die, and another fifth to
return home invalided. 58 This immunity in the negro seems to
be partly inherent, depending on some unknown peculiarity of
constitution, and partly the result of acclimatisation. Pouchet 59
53 Sir Andrew Smith, as quoted the Historical Sketch (p. xvi.) to my
by Knox, * Races of Man * 1850, p. . * Origin of Species.' Various cas^s
473. of colour correlated with constitu-
54 See De Quatrefages on this tional peculiarities are given in my
head, * Revue des Cours Scienti- * Variation of Animals under Do-
fiques,' Oct. 17, 1868, p. 731. mestication,' vol. ii. pp. 227, 335.
55 Livingstone's * Travels and Re- " See, for instance, Nott and
searches in S. Africa/ 1857, pp. Gliddon, * Types of Mankind,' p. 68.
338, 329. D'Orbigny, as quoted by 6 * Major Tulloch, in a paper read
Godron, * De l'Espece,* vol. ii. p. before the Statistical Society, Apni
266. 20th, 1840, and given in the « Athe-
56 See a paper read before the naeum,' 1840, p. 353.
Royal Soc. in 1813, and published M 'The Plurality of the Human
in fcis.Essays in 1818. I have given Race ' (transiat.), 1864, p. 60.
*a account of Dr. Wells' views in
k
194 The Descent of Man. f ah* I.
states that the negro regiments recruited near the Soudan, and
oorrowed from the Viceroy of Egypt for the Mexican war,
escaped the yellow-fever almost equally with the negroes origin-
ally brought ffomfarious parts of Africa and accustomed to the
climate of the "West Indies. That acclimatisation plays a part,
is shewn by the many cases in which negroes have become some-
what liable to tropical fevers, after having resided for some time
in a colder climate. 60 The nature of the climate under which the
white races have long resided, likewise has some influence on
them; for during the fearful epidemic of yellow-fever in
Demerara during 1837, Dr. Blair found that the death-rate of the
immigrants was proportional to the latitude of the country
whence they had come. With the negro the immunity, as far as
it is the result of acclimatisation, implies exposure during a
prodigious length of time ; for the aborigines of tropical America
who have resided there from time immemorial, are not exempt
from yellow fever; and the Eev. H. B. Tristram states, that
there are districts in Northern Africa which the native inhabit-
ants are compelled annually to leave, though the negroes can
remain with safety.
That the immunity of the negro is in any degree correlated
I with the colour of his skin is a mere conjecture : it may be
1 correlated with some difference in his blood, nervous system, or
1 other tissues. Nevertheless, from the facts above alluded to, and
(from some connection apparently existing between complexion
and a tendency to consumption, the conjecture seemed to me
not improbable. Consequently I endeavoured, with but little
success, 61 to ascertain how far it holds good. The late Dr.
60 Quatrefages, * Unite de 1'Espece " is some limited degree of relation
Humaine,' 1861, p. 205. Waitz, " between the colour of the races of
* Iutroduct. to Anthropology/ trans- " man and the climate inhabited by
lat. vol. i. 1863, p. 124. Living- " them ; the following investiga-
stone gives analogous cases in his " tion seems worth consideration.
* Travels.' " Namely, whether there is any re-
61 In the spring of 1862 I ob- " lation in Europeans between the
tained permission from the Director- " colour of their hair, and their
General of the Medical department " liability to the diseases of tropica!
of the Army, to transmit to the " countries. If the surgeons of the
surgeons of the various regiments " several regiments, when stationed
on foreign service a blank table, " in unhealthy tropical districts,
with the following appended re- " would be so good as first to count,
marks, but I have received no re- " as a standard of comparison, how
turns. " As several well-marked " many men, in the force whence
" cases have been recorded with " the sick are drawn, have darii
w our domestic animals of a relation " and light-coloured hair, and hah
" between the colour of the dermal " of intermediate or doubtful tints ;
u appendages and the constitution ; "w^ if a similar account were
"and it being notorious that there " kept by the same medical gentle
Ckap, VIL The Formation of Races. 195
Daniel], who had long lived on the West Coast of Africa, told me
that he did not believe in any such relation. He was himself
unusually fair, and had withstood the climate in a wonderful
manner. When he first arrived as a boy on the coast, an old and
experienced negro chief predicted from his appearance that this
would prove the case. Dr. Nicholson, of Antigua, after having
attended to this subject, writes to me that he does not think that
dark-coloured Europeans escape the yellow-fever more than
those that are light-coloured. Mr. J. M. Harris altogether
denies that Europeans with dark hair withstand a hot climate
better than other men : on the contrary, experience has taught
him in making a selection of men for service on the coast oi
Africa, to choose • those with red hair. 62 As far, therefore, as
these slight indications go, there seems no foundation for the
hypothesis, that blackness has resulted from the darker and
darker individuals having survived better during long exposure
to fever-generating miasma.
Dr. Sharpe remarks, 63 that a tropical sun, which burns and
blisters a white skin, does not injure a black one at all ; and, as
he adds, this is not due to habit in the individual, for children
only six or eight months old are often carried about naked, and
are not affected. I have been assured by a medical man, that
some years ago during each summer, but not during the winter,
his hands became marked with light brown patches, like,
*' men, of all the men who suffered " of generations."
" from malarious anil yellow fevers, OT * Anthropological Review/ Jan.
" or from dysentery, it would soon 1866, p. xxi. Dr. Sharpe also says,
" be apparent, after some thousand with respect to India (* Man a Spe-
" cases had been tabulated, whether cial Creation,' 1873, p. 118), that
" there exists any relation between " it has been noticed by some medi-
" the colour of the hair and consti- " cal officers that Europeans with
" tutional liability to tropical dis- " light hair and florid complexions
" eases. Perhaps no such relation " suffer less from diseases of tropical
" would be discovered, but the in- " countries than persons with dark
" vestigation is well worth making, "hair and sallow complexions;
" In case any positive result were " and, so far as I know, there ap-
" obtained, it might be of some " pear to be good grounds for this
" practical use in selecting men for " remark." On the other hand,
" any particular service. Theoreti- Mr. Heddle, of Sierra Leone " who
" cally the result would be of high " has had more clerks killed under
"interest, as indicating one means " him than any other man," by the
" by which a race of men inhabiting climate of the West African Coast
** from a remote period an un- (W. Reade, * African Sketch Book/
" healthy tropical climate, might vol. ii. p. 522), holds a directly
" have become dark-coloured by opposite view, as does Capt. Burton.
"the better preservation of dark- 63 * Man a Special Creation/ 1873
" haired or dark-complexioned in- p. 119.
* dividuals during a long succession
o 2
196 The Descent of Matt. Pass? L
although larger than freckles, and that these patches were nevei
affected by sun-burning, whilst the white parts of his skin
have on several occasions been much inflamed and blistered.
With the lower animals there is, also, a constitutional difference
in liability to the action of the sun between those parts of the
skin clothed with white hair and other parts. 64 Whether the
saving of the skin from being thus burnt is of sufficient impor-
tance to account for a dark tint having been gradually acquired
by man through natural selection, I am unable to judge. If it
be so, we should have to assume that the natives of tropical
America have lived there for a much shorter time than the
negroes in Africa, or the Papuans in the southern parts of the
Malay archipelago, just as the lighter-coloured Hindoos have
resided in India for a shorter time than the darker aborigines of
the central and southern parts of the peninsula.
Although with: our present knowledge jwe cannot account for
the differences of colour in the races of man, through any
advantage thus gained, or from the direct action of climate ; yet
we must not quite ignore the latter agency, for there is good
reason to believe that some inherited effect is thus produced^ 6
|" We have seen in the second chapter that the conditions of life
j affect the development of the bodily frame in a direct manner,
I and that the effects are transmitted. Thus, as is generally
/ admitted, the European settlers in the United States undergo a
I slight but extraordinarily rapid change of appearance. Their
bodies and limbs become elongated; and I hear from Co/.
Bernys that during the late war in the United States, good
evidence was afforded of this fact by the ridiculous appearance
presented by the German regiments, when dressed in ready-made
clothes manufactured for the American market, and which were
much too long for the men in every way. There is, also, a con-
siderable body of evidence shewing that in the Southern States
the house-slaves of the third generation present a markedly
different appearance from the field-slaves. 63
6 * Variation of Animab and settled in Georgia, hare acquired in
.Plants under Domestication/ vol. ii. the course of two generations dark:
pp. 336, 337. hair and eyes. Mr. D. Forbes in-
65 See, for instance, Quatrefages forms me that the Quichuas in th«s
(* Revue des Cours Scientifiques/ Andes vary greatly in colour, ao
Oct. 10, 1868, p. 724) on the effects cording io the position of the valleys
of residence in Abyssinia and Arabia, inhabited by them.
.'*nd other analogous cases. Dr. 66 Harlan, 'Medical Researches/
Rolle (' Der Mensch, seine Abstam- p. 532. Quatrefages (' Unite' d«?
mung,' &c, 1865, s. 99) states, on 1'Espece Humaine,' 1861, p. 128)
the authority of Khanikof, that the has collected much evidence on thia
greater number of German families head.
Chap. VII. The Formation of Races. 197
If, however, we look to the races of man as distributed over
the world/we must infer that their characteristic differences can-
not be accounted for by the direct action of different conditions
of life, even after exposure to them for an enormous period of
time. The Esquimaux live exclusively on animal food ; they are
clothed in thick fur, and are exposed to intense cold and to
prolonged darkness; yet they do not differ in any extreme
degree from the inhabitants of Southern China, who live entirely
on vegetable food, and are exposed almost naked to a hot, glaring
climate. The unclothed Fuegians live on the marine produc-
tions of their inhospitable shores; the Botocudos of Brazil
wander about the hot forests of the interior and live chiefly on
vegetable productions ; yet these tribes resemble each other so
closely that the Fuegians on board the " Beagle " were mistaken
by some Brazilians for Botocudos. The Botocudos again, as
well as the other inhabitants of tropical America, are wholly
different from the Negroes who inhabit the opposite shores of
the Atlantic, are exposed to a nearly similar climate, and follow
nearly the same habits of life.
Nor can the differences between the races of man be accounted
for by the inherited effects of the increased or decreased use of
parts, except to a quite insignificant degree. Men who habitu-
ally live in canoes, may have their legs somewhat stunted;
those who inhabit lofty regions may have their chests enlarged ;j
and those who constantly use certain sense-organs may have the
cavities in which they are lodged somewhat increased in size, and
their features consequently a little modified. With civilised
nations, the reduced size of the jaws from lessened use — the
habitual play of different muscles serving to express different
emotions — and the increased size of the brain from greater
intellectual activity, have together produced a considerable
effect on their general appearance when compared with
savages.^ Increased bodily stature, without any corresponding
increase in the size of the brain, may (judging from the pre-
viously adduced case of rabbits), have given to some races an
elongated skull of the dolichocephalic type.
Lastly, the little-understood principle of correlated develop-
ment has sometimes come into action, as in the case of great
muscular development and strongly projecting supra-orbital ''
ridges. The colour of the skin and hair are plainly correlated, as *
is the texture of the hair with its colour in the Mandans of
North America. 88 The colour also of the skin, and tho odour
eT See Prof. Schaaffhausen, trans- 88 Mr. Catlin states (*N. Ameri-
iat. in 'Anthropological Review,' can Indians,' 3rd edit. 1842, vol. 1.
Oct. 1868, p. 439. p. 49) that in the whole tribe of
198 The Descent of Man, Part l
emitted "by It, are likewise in some manner connected. With the
breeds of sheep the number of hairs within a given space and the
number of the excretory pores are related.® 9 If we may judge
from the analogy of our domesticated animals, many modifica-
tions of structure in man probably come under this principle of
correlated development.
We have now seen that the external characteristic differences
between the races of man cannot be accounted for in a satisfac-
tory manner by the direct action of the conditions of life, nor by
the effects of the continued use of parts, nor through the
principle of correlation, ye are_ therefore led to_i ncjQiire
w hether slig ht individual difference s. _to~ wh ich man^is^ emi-
nently IJableTmay not have been preserved an<J augmented
during along series prgenerations throttgn^nat ural .selection...
.But here we are at once met by the objection that beneficial
variations alone can be thus preserved ; and as far as we are
enabled to judge, although always liable to err on this head, none
of the differences between the races of man are of any direct or
special service to him. The intellectual and moral or social
faculties must of course be excepted from this remark. The great
variability of all the external differences between the races of man,
likewise indicates that they cannot be of much importance ; for
if important, they would long ago have been either fixed and
preserved, or eliminated. In this respect man resembles those
forms, called by naturalists protean or polymorphic, which have
; remained extremely variable, owing, as it seems, to such varia-
tions being of an indifferent nature, and to their having thus
I escaped the action of natural selection.
We have thus far been baffled in all our attempts to account
for the differences between the races of man ; but there remains
one important agency, namely Sexual Selection, which appears to
have acted powerfully on man, as on many other animals. I do
not intend to assert that sexual selection will account for all the
differences between the races. An unexplained residuum is left,
about which we can only say, in our ignorance, that as indivi-
duals are continually born with, for instance, heads a little
rounder or narrower, and with noses a little longer or shorter,
such slight differences might become fixed and uniform, if the
the Mandans, about one in ten or fine and soft.
twelve of the members, of all ages 69 On the odour of the skin.
and both sexes, have bright silvery Godron, * Sur TEspece,' torn. ii. j>.
grey hair, which is hereditary. 217. On the pores in the skin,
Now this hair is as coarse and Dr. Wilckens, i Die Aufgaben der
laarsh as that of a horse's mane, Landwirth. Zootechnik/ 18t'tf, s, 7*
whilst the hair of other colours is
Chap. VII. Structure of the Brain. 199
unknown agencies which induced them were to act in a more
constant manner, aided by long-continued intercrossing. Such
variations come under the provisional class, alluded to in our
second chapter, which for the want of a better term are often
called spontaneous. Nor do I pretend that the effects of sexual
selection can be indicated with scientific precision ; but it can be
shewn that it would be an inexplicable fact if man had not been
modified by this agency, which appears to have acted powerfully
on innumerable animals. It can further be shewn that thej
differences between the races of man, as in colour, hairiness,/
form of features, &c, are of a kind which might have been/
expected to come under the influence of sexual selection. But in
order to treat this subject properly, I have found it necessary to
pass the whole animal kingdom in review. I have therefore
devoted to it the Second Part of this work. At the close I shall
return to man, and, after attempting to shew how far he has
been modified through sexual selection, will give a brief summary
of the chapters in this First Part.
Note on the Resemblances and Differences in the? Structure
and the Development of the Brain in Man and Apes. By
Professor Huxley, F.R.S.
The controversy respecting the nature and the extent of the differ-
ences in the structure of the brain in man and the apes, which arose
some fifteen years ago, has not yet come to an end, though the subject
matter of the dispute is, at present, totally different from what it was
formerly. It was originally asserted and re-asserted, with singular
pertinacity, that the brain of all the apes, even the highest, differs from •
that of man, in the absence of such conspicuous structures as the
posterior lobes of the cerebral hemispheres, with the posterior cornu of
the lateral ventricle and the hippocampus minor, contained in those
lobes, which are so obvious in man.
But the truth that the three structures in question are as well deve-
loped in apes' as in human brains, or even better ; and that it is character-
istic of all the Primates (if we exclude the Lemurs) to have these parts
well developed, stands at present on as secure a basis as any proposition
in comparative anatomy. Moreover, it is admitted by every one of the
long series of anatomists who, of late years, have paid special attention to
the arrangement of the complicated sulci and gyri which appear upon
the surface of the cerebral hemispheres in man and the higher apes,
that they are disposed after the very same pattern in him, ay in them.
Every principal gyrus and sulcus of a chimpanzee's brain is clearly
represented in that of a man, so that the terminology which applies to
the one answers for the other. On this point there is no difference of
opinion. Some years since, Professor Bischoff published a memoir 70 on
the cerebral convolutions of man and apes; and as the purpose of
my learned colleague was certainly not to diminish the value of the
™ 'Die Grosshirn-Windungen des Menschenj' * Abhandiucg^r der K
Uayerischen Akaderpie.* Bl x., 1868.
200 The Descent of Man. p A rt I
differences between apes and men in this respect, I am glad to make a
citation from him.
" That the^ apes, and especially the orang, chimpanzee and gorilla,
" come very close to man in their organisation, much nearer than to any
*' other animal, is a well known fact, disputed by nobody. Looking at
" the matter from the point of view of organisation alone, no one probably
" would ever have disputed the view of Linnaeus, that man should be
44 placed, merely as a peculiar species, at the head of the mammalia and ot
** those apes. Both shew, in all theix- organs, so close an affinity, that the
" most exact anatomical investigation is needed in order to demonstrate
** those differences which really exist. So it is with the brains. The
" brains of man, the orang, the chimpanzee, the gorilla, in spite of all
** the important differences which they present, come very close to one
"'another" (I.e. p. 101).
There remains, then, no dispute as to the resemblance in fundamental
characters, between the ape's brain and man's ; nor any as to the won-
derfully close similarity between the chimpanzee, orang and man, in
even the details of the arrangement of the gyri and sulci of the cerebral
hemispheres. Nor, turning to the differences between the brains ot
the highest apes and that of man, is there any serious question as to
the nature and extent of these differences. It is admitted that the man's
cerebral hemispheres are absolutely and relatively larger than those of
the orang and chimpanzee ; that his frontal lobes are less excavated by
the upward protrusion of the roof of the orbits ; that his gyri and sulci
are, as a rule, less symmetrically disposed, and present a greater number
of secondary plications. And it is admitted that, as a rule, in man, the
temporo-occipital or " external perpendicular " fissure, which is usually
so strongly marked a feature of the ape's brain is but faintly marked.
But it is also clear, that none of these differences constitutes a sharp
demarcation between the man's and the ape's brain. In respect to the
external perpendicular fissure of Gratiolet, in the human brain, for
instance, Professor Turner remarks : 71
" In some brains it appears simply as an indentation of the margin of
u the hemisphere, but, in others, it extends for some distance more or less
" transversely outwards. I saw it in the right hemisphere of a female
" brain pass more than two inches outwards ; and in another specimen,
" also the right hemisphere, it proceeded for four-tenths of an inch out-
u wards, and then extended downwards, as far as the lower margin of the
" outer surface of the hemisphere. The imperfect definition of this fissure
" in the majority of human brains, as compared with its remarkable dis-
" tinctness in the brain of most Quadrumana, is owing to the presence, in
" the former, of certain superficial, well marked, secondary convolutions
'* which bridge it over and connect the parietal with the occipital lobe.
*' The closer the first of these bridging gyri lies to the longitudinal
" fissure, the shorter is the external parieto-occipital fissure." (1. c. p. 12.)
The obliteration of the external perpendicular fissure of Gratiolet,
therefore, is not a constant character of the human brain. On the other
hand, its full development is not a constant character of the higher
ape's brain. For, in the chimpanzee, the more or less extensive oblitera-
tion of the external perpendicular sulcus by 4t bridging convolutions," ou
©ns side or the other, has been noted over and over again by Pro!
" 'Convolutions of the Human Cerebrum Topographically Considered.
'866, p. 12,
Chap. VII. Structure of tlie Brain. 201
JJoIleston, Mr. Marshall, M. Broca and Professor Turner. At the
conclusion of a special paper on this subject the latter writes : 72
M The three specimens of the brain of a chimpanzee just described,
w prove, that the generalisation which Gratiolet has attempted to draw of
" the complete absence of the first connecting convolution and the
" concealment of the second, as essentially characteristic features in the
" brain of this animal, is by no means universally applicable. In only one
" specimen did the brain, in these particulars, follow the law which
" Gratiolet has expressed. As regards the presence of the superior bridg-
" ing convolution, I am inclined to think that it has existed in one hemi-
** sphere, at least, in a majority of the brains of this animal which have, up
" to this time, been figured or described. The superficial position of the
" second bridging convolution is evidently less frequent, and has as yet,
" I believe, only been seen in the brain (A) recorded in this cominuni-
li cation. The asymmetrical arrangement in the convolutions of the
** two hemispheres, which previous observers have referred to in their
u descriptions is also well illustrated in these specimens." (pp. 8, 9.)
Even were the presence of the temporo-occipital, or external per-
pendicular, sulcus a mark of distinction between the higher apes and
man, the value of such a distinctive character would be rendered very
doubtful by the structure of the brain in the Platyrhine apes. In fact
while the temporo-occipital is one of the most constant of sulci in
the Catarhine, or Old World, apes, it is never very strongly developed
in the New World apes; it is absent in the smaller Platyrhini;
rudimentary in Pithecia ; 73 and more or less obliterated by bridging
convolutions in Ateles.
■ A character which is thus variable within the limits of a single group
can have no great taxonomie value.
It is further established, that the degree of asymmetry of the convolu-
tion of the two sides in the human brain is subject to much individual
variation ; and that, in those individuals of the Bushman race who have
been examined, the gyri and sulci of the two hemispheres are consider-
ably less complicated and more symmetrical than in the European
brain, while, in some individuals of the chimpanzee, their complexity
and asymmetry become notable. This is particularly the case in the
brain of a young male chimpanzee figured by M. Broca. (* L'ordre
des Primates,' p. 165, fig. 11.)
Again, as respects the question of absolute size, it is established that
the difference between the largest and the smallest healthy human
brain is greater than the difference between the smallest healthy
human brain and the largest chimpanzees or orang's brain.
Moreover, there is one circumstance in which the orang's and chim-
panzee's brains resemble man's, but in which they differ from the lower
apes, and that is the presence of two corpora candicantia — the
Cynomorpha having but one.
In view of these facts I do not hesitate in this year 1874, to repeat
and insist upon the proposition which I enunciated in 1863. 74
"So far as cerebral structure goes, therefore, it is clear that man
n Notes more especially on the " Flower 'On the Anatomy of
bridging convolutions in the Brain Pithecia MonacJius* ' Proceedings of
of the Chimpanzee, 'Proceedings of the Zoological Society,' 1862.
tiw Royal Society of Edinburgh,' :i < Man's PJace in Nature,' p. 102
1365-6. v
202 The Descent of Man. Paiit I,
** differs les3 from the chimpanzee or the orang, than these do even
vt from the monkeys, and cnat the difference between the brain of the
" chimpanzee and of man is almost insignificant, when compared with
" that between the chimpanzee brain and that of a Lemur."
In the paper to which I have referred, Professor Bischoff does not
deny the second part of this statement, but he first makes the irrelevant
remark that it is not wonderful if the brains of an orang and a Lemur
are very different ; and secondly, goes on to assert that, " If we succes-
* sively compare the brain of a man with that of an orang ; the brain of
" this with that of a chimpanzee ; of this with that of a gorilla, and so
" on of a Hylobates, Semnopithecus, Ggnocephalus, Cercopithecus, Macacus,
" Cebus, Callithrix, Lemur, Stenops, Hapale, we shall not meet with a
" greater, or even as great a, break in the degree of development of the
"convolutions, as we find between the brain of a man and that of an.
" orang or chimpanzee."
To which I reply, firstly, that whether this assertion be true
or false, it has nothing whatever to do with the proposition enunciated
in 'Man's Place in Nature,' which refers not to the development of the
convolutions alone, but to the structure of the whole brain. If Professor
Bischoff had taken the trouble to refer to p. 96 of the work he criticises,
in fact, he would have found the following passage : " And it is a
" remarkable circumstance that though, so far as our present know-
" ledge extends, there is one true structural break in the series of forms
"of Simian brains, this hiatus does not lie between man and the
" manlike apes, but between the lower and the lowest Simians, or in
•' other words, between the Old and New World apes and monkeys and
"the Lemurs. Every Lemur which has yet been examined, in fact,
" has its cerebellum partially visible from above ; and its posterior lobe,
" with the contained posterior cornu and hippocampus minor, more or
"less rudimentary. Every marmoset, American monkey, Old World
" monkey, baboon, or manlike ape, on the contrary, has ii3 cerebellum
*' entirely hidden, posteriorly, by the cerebral lobes, and possesses a
** large posterior cornu with a well-developed hippocampus minor."
This statement was a strictly accurate account of what was known
when it was made; and it does not appear to me to be more than
apparently weakened by the subsequent discovery of the relatively
small development of the posterior lobes in the Siamang and in the
Howling monkey. Notwithstanding the exceptional brevity of the
posterior lobes in these two species, no one will pretend that their
brains, in the slightest degree, approach those of the Lemurs. And
if, instead of putting Hapale out of its natural place, as Professor
Bischoff most unaccountably does, we write the series of animals
he has chosen to mention as follows : Homo, Pithecus, Troglodytes,
Hylobates, Semnopithecus, Cynocephalus, Cercopithecus, Macacus, Cebus,
Callithrix, Hapale, Lemur, Stenops, I venture to reaffirm that the
great break in this series lies between Hapale and Lemur*, and that
this break is considerably greater than that between any other two
terms of that series. Professor Bischoff ignores the fact that long
before he wrote, Gratiolet had suggested the separation of the Lemurs
from the other Primates on the very ground of the difference in their
cerebral characters ; and that Professor Flower had made the following
observations in the course of his description of the brain of the Javad
Loris '*
TS * Transactions of the Zoological Society,' vol. v. 1862.
Chap. VII. Structure of the Brain. 203
" And it is especially remarkable that, in the development of the
u posterior lobes, there is no approximation to the Lemurine, short
" hemisphered, brain, in those monkeys which are commonly supposed
•' to approach this family in other respects, viz., the lower members oi
*' the Platyrhine group,"
So far as the structure of the adult brain is concerned, then, the very
considerable additions to our knowledge, which have been made by the
researches of so many investigators, during the past ten years, fully
justify the statement which I made in 1863, But it has been said
that, admitting the similarity between the adult brains of man and
apes, they are nevertheless, in reality, widely different, because the?
exhibit fundamental differences in the mode of their development. No
one would be more ready than I to admit the 'force of this argument, if
such fundamental differences of development really exist. But I deny
that they do exist. On the contrary, there is a fundamental agree-
ment in the development of the brain in men and apes.
Gratiolet originated the statement that there is a fundamental
difference in the development of the brains of apes and that of man —
consisting in this ; that, in the apes, the sulci which first make their
appearance are situated on the posterior region of the cerebral hemi-
spheres, while, in the human foetus, the sulci first become visible on the
frontal lobes. 76
This general statement is based upon two observations, the one of a
Gibbon almost ready to be born, in which the posterior gyri were " well
" developed," while those of the frontal lobes were " hardly indicated " 7r
(1. c. p.. 39), and the.other of a human foetus at the 22nd or 23rd week
of uterogestation, in which Gratiolet notes that the insula, was un-
covered, but that nevertheless " des incisures sement 1e lobe anterieur,
" une scissure peu profonde indique la separation du lobe occipital, tres-
Vi " Chez tous les singes, les plis Rolando, and one of the frontal
" posterieurs se deVeloppent les pre- sulci, plainly enough. Nevertheless,
il miers ; les plis ant^rieurs se M. Alix, in his * Notice sur les
" de>eloppent plus tard, aussi la travaux anthropologiques de Gratio-
" vertebre occipitale et la parietale let' (Mern. de la Societe d'Anthrp-
"sont-ellesrelativementtres-grandes pologie de Paris/ 1868, page 32. ),
44 chez le fetus. L'Homme presente writes thus : " Gratiolet a eu e litre
44 une exception remarquable quant " les mains le cerveau d'un fcetus de
44 a l'^poque de l'apparition des plis " Gibbon, singe erninemment su-
" frontaux, qui sont les premiers " p^rieur, et tellement rapproche de
" indiqu^s ; mais le developpement " l'orang, que des naturalistes tres-
•* g^n^ral du lobe frontal, envisage " comp^tents Pont range parmi les
" seulement par rapport a son " anthropo'ides. M. Huxley, par ex-
" volume, suit les memeslois que dans " emple, n'hesite pas sur ce point.
" les singes:" Gratiolet, 'Memoire " Eh bien, c'est sur le cerveau d'un
sur les plis c£r<£braux de THomnie " fcetus de Gibbon que Gratiolet a
et des Primates/ p. 39, Tab. iv. " vu les circonvolutions du lobe tern-
fig. 3. " poro-sphenoidal deja developpees
77 Gratiolet's words are (1. c. p. " lor squ' il n' existent pas encore deplii
39): "Dans le fcetus dont il s'agit " sur le lobe frontal, II e"tait done
" les plis cere*braux posterieurs sont " bien autorise" a dire que, cIipz
" bien de>elopp£s, tandis que les " Phomme les circonvolutions appa-
il plis du lobe frontal sont a peine " raissent d'a en to, tandis que chei
** indiqnes." the figure, however " les singes elles se d£velc*pent
(Fl. iv. fie, 3\ shews the fissure of " d'ou ea «."
204 The Descent of Man. Part L
u re'duit, d'ailleurs cles cette epoque. Le reste de la surface cerebrale
" est encore absolument lisse."
Three views of this brain are given in Plate II. figs, 1, 2, 3, of the
work cited, shewing the upper, lateral and inferior views of the hemi-
spheres, but not the inner view. It is worthy of note that the figure
by no means bears out Gratiolet's description, inasmuch as the fissure
(anterotemporal) on the posterior half of the face of the hemisphere ; is
more marked than any of those vaguely indicated in the anterior half.
If the figure is correct it in no way justifies Gratiolet's conclusion :
** II y a done entre ces cerveaux [those of a Callithrix and of a Gibbon] et
u celui du foetus humain une difference fondamental. Chez celui-ci, long-
" temps avant que les plis temporaux apparaissent, les plis frontaux
" essay ent d'exister."
Since Gratiolet s time, however, the development of the gyri and
sulci of the brain has been made the subject of renewed investigation
by Schmidt, Bischoff, Pansch, 78 and more particularly by Ecker, 79 whose
work is not only the latest, but by far the most complete, memoir on
the subject.
The final results of their inquiries may be summed up as follows : —
1. In the human foetus, the sylvian fissure is formed in the course of
the third month of uterogestation. In this, and in the fourth month,
the cerebral hemispheres are smooth and rounded (with the exception
of the sylvian depression), and they project backwards far beyond the
cerebellum.
2. The sulci, properly so called, begin to appear in the interval
between the end of the fourth and the beginning of the sixth month of
foetal life, but Ecker is careful to point out that, not only the time, but
the order, of their appearance is subject to considerable individual
variation. In no case, however, are either the frontal or the temporal
sulci the earliest.
The first which appears, in fact, lies on the inner face of the hemi-
sphere (whence doubtless Gratiolet, who does not seem to have examined
that face in his foetus, overlooked it), and is either the internal perpen-
dicular (occipito-parietal), or the calcarine sulcus, these two being close
together and eventually running into one another. As a rule the
occipito-parietal is the earlier of the two.
3. At the latter part of this period, another sulcus, the " posterio,
parietal," or " Fissure of Kolando " is developed, and it is followed, in
the' course of the sixth month, by the other principal sulci of the
frontal, parietal, temporal and occipital lobes. There is, however, no
clear evidence that one of these constantly appears before the other
and it is remarkable that, in the brain at the period described and
figured by Ecker (I. c. p. 212-13, Taf. II. figs. 1, 2, 3, 4), the antero-
temporal sulcus (scissure paralUle) so characteristic of the ape's brain,
is as well, if not better developed than the fissure of Kolando, and is
much more marked than the proper frontal sulci.
Taking the facts as they now stand, it appears to me that the order
of the appearance of the sulci and gyri in the foetal human brain is in
perfect harmeny with the general doctrine of evolution, and with the
78 ' Ueber die typische Anordnung 79 ' Zur Entwickelcmgs Geschichte
der Furchen und Windungen auf der Furchen und Windungen der
den Grosshirn-Hemisp^aren des Grosshirn-Hemispharen im Foetus
Meuschen und der Affen.' 'Archiv des MenscheD.' l Archiv fiir Antbro
fur Anthropologic,' uh, 1868. pologio,' in., 1868.
Chap. Vli. Structure of the Brain. 2oJ
view that man has been evolved from some ape- like form ; though thero
Can be no doubt that that form was, in many respects, different from
any member of the Primates now living.
Von Baer taught us, half a century ago, that, in the course of theii
development, allied animals put on, at first, the characters of the greater
groups to which they belong, and, by degrees, assume those which restrict
them within the limits of their family, genus, and species ; and he
proved, at the same time, that no developmental stage of a higher
animal is precisely similar to the adult condition of any lower animal.
It is quite correct to say that a frog passes through the condition of a
fish, inasmuch as at one period of its life the tadpole has all the cha-
racters of a fish, and, if it went no further, would have to be grouped
among fishes. But it is equally true that a tadpole is very different
from any known fish.
In like manner, the brain of a human foetus, at the fifth month, may
correctly be said to be, not only the brain of an ape, but that of an
Arctopithecine or marmoset-like ape ; for its hemispheres, with their
great posterior lobster, and with no sulci but the sylvian and the
calcarine, present the characteristics found only in the group of the
Arctopithecine Primates. But it is equally true, as Gratiolet remarks,
that, in its widely open sylvian fissure, it differs from the brain of any
actual marmoset. No doubt it would be much more similar to the brain
of an advanced foetus of a marmoset. But we know nothing whatever
of the development of the brain in the marmosets. In the Platyrhini
proper, the only observation with which I am acquainted is due to
Pansch, who found in the brain of a fcetal Cebus Apella, in addition to
the sylvian fissure and the deep calcarine fissure, only a very shallow
anterotemporal fissure (scissure parallele of Gratiolet.)
Now this fact, taken together with the circumstance that the antero-
temporal sulcus is present in such Platyrhini as the Saimiri, which
present mere traces of sulci on the anterior half of the exterior of the
cerebral hemispheres, or none at all, undoubtedly, so far as it goes,
affords fair evidence in favour of Gratiolet's hypothesis, that the
posterior sulci appear before the anterior, in the brains of the
Platyrhini. But, it by no means follows, that the rule which may hold
good for the Platyrhini extends to the Catarhini. We have no in-
formation whatever respecting the development of the brain in the
Cynnmorpha; and, as regards the Anthropomorpha, nothing but the
account of the brain of the Gibbon, near birth, already referred to.
At the present moment, there is not a shadow of evidence to shew
that the sulci of a chimpanzee's, or orang's, brain do not appear in the
same order as a man's.
Gratiolet opens his preface with the aphorism. *' II est dangereux
" dans les sciences de conclure trop vite." I fear he must have for-
gotten this sound maxim by the time he had reached the discussion of
the differences between men and apes, in the body of his work.. Nc
doubt, the excellent author of one of the most remarkable contributions
to the just understanding of the mammalian brain which has ever been
made, would have been the first to admit the insufficiency of his data
had he lived to profit by the advance of inquiry. The misfortune is
that his conclusions have been employed by persons incompetent to
appreciate their foundation, as arguments in favour of obscurantism. 80
80 For example, M. l'Abb<S Lecomte winisme et Fcngine de THomme
ia his terrible pamphlet < Le Dar- 1873.
200 Tkt Descent of Man. pAirt t
But it is important to remark that, whether Gratiolet was right or
wrong in his hypothesis respecting the relative order of appearance of
the temporal and frontal sulci, the fact remains ; that, before either
temporal or frontal sulci, appear, the foetal brain of man presents
characters which are found only in the lowest group of the Primates
(leaving out the Lemurs) ; and that this is exactly what we should
expect to be the case, if man has resulted from the gradual modifica-
tion of the aams form as that from which the other Primates have
sprung.
t m )
Part II
SEXUAL SELECTION.
CEAPTEK Vni.
Principles of Sexual Selection.
Secondary sexual characters — Sexual selection — Manner of action- 1 — Ex-
cess of males — Polygamy — The male alone generally modified through
sexual selection — Eagerness of the male — Variability of the male —
Choice exerted by the female — Sexual oompared with natural selection
— Inheritance, at corresponding periods of life, at corresponding seasons
of the year, and as limited by sex — Relations between the several forms
of inheritance — Causes why one sex and the young are not modified
through sexual selection — Supplement on the proportional numbers oi
the two sexes throughout the animal kingdom — The proportion of the
sexes in relation to natural selection.
With animals which have their sexes separated, the males
necessarily differ from the females in their organs of reproduction ;
and these are the primary sexual characters. But the sexes
often differ in what Hunter has called secondary sexual charac-
ters, which are not directly connected with the act of reproduc-
tion ; for instance, the male possesses certain organs of sense' or
locomotion, of which the female is quite destitute, or 'has them
more highly-developed, in order that he may readily find or
reach her ; or again the male has special organs of prehension for
holding her securely. These latter organs, of infinitely diversified
kinds, graduate into those which are commonly ranked as
primary, and in some cases can hardly be distinguished from
them ; we see instances of this in the complex appendages at the
apex of the abdomen in male insects. Unless indeed we confine
the term " primary" to the reproductive glands, it is scarcely
possible to decide which ought to be called primary and whicli
secondary.
The female often differs from the male in having organs for the
nourishment or protection of her young, such as the majpmary
2o8 The Descent of Man. P±ut 11
glands of mammals, and the abdominal sacks of the marsupials.
In some few cases also the male possesses similar organs, which
are wanting in the female, such as the receptacles for the
ova in certain male fishes, and those temporarily developed in
certain male frogs. The females of most bees are provided with
a special apparatus for collecting and carrying pollen, and their
ovipositor is modified into a sting for the defence of the larvse
and the community. Many similar cases could be given, but
they do not here concern us. There are, however, other sexual
differences quite unconnected with the primary reproductive
organs, and it with is these that we are more especially concerned
— such as the greater size, strength, and pugnacity of the male,
his weapons of offence or means of defence against rivals, his
gau£y colouring and various ornaments, his power of song, and
other such characters.
Besides the primary and secondary sexual differences, such as
the foregoing, the males and females of some animals differ in
structures related to different habits of life, and not at all, or *
only indirectly, to the reproductive functions. Thus the females
of certain flies (Culicidse and Tabanidae) are blood-suckers,
whilst the males, living on flowers, have mouths destitute of
mandibles. 1 The males of certain moths and of some crustaceans
(fc. g. Tanais) have imperfect, closed mouths, and cannot feed.
The complemental males of certain Cirripedes live like epiphytic
plants either on the female or the hermaphrodite form, and are
destitute of a mouth and of prehensile limbs. In these cases it is
the male which has been modified, and has lost certain important
organs, which the females possess. In other cases it is the female
which has lost such parts; for instance, the female glow-worm is
destitute of wings, as also are many female moths, some of which
never leave their cocoons. Many female parasitic crustaceans
have lost their natatory legs. In some weevil-beetles (Curcu-
lionidae) there is a great difference between the male and female
in the length of the rostrum or snout ; 2 but the meaning of this
and of many analogous differences, is not at all understood,
Differences of structure between the two sexes in relation to
different habits of life are generally confined to the lower
animals ; but with some few birds the beak of the male differs
from that of the female. In the Huia of New Zealand the
difference is wonderfully great, and we hear from Dr. Buller
1 Westwood, 'Modern Class, of 2 Kirby and Spence, 'Iutroduc-
Insects,' vol. ii. 1840, p. 541. For tion to Entomology/ vol. iii. 1826
the statement about Tanais, men- p. 309.
tioned below, I am indebted to Fritz & 'Birds of New Zealand/ 1ST 2
Miiller. p, m.
Oinr. YIIL Sexual Selection, 209
that the male uses his strong beak in chiselling the larvae of
•nsects out of decayed wood, whilst the female probes the softer
parts with her far longer, much curved and pliant beak : and
thus they mutually aid each other. In most cases, differences of
structure between the sexes are more or less directly connected
with the propagation of the species : thus a female, which has to
nourish a multitude of ova, requires more food than the male,
and consequently requires special means for procuring it. A male
animal, which lives for a very short time, might lose its organs
for procuring food through disuse, without detriment ; but he
would retain his locomotive organs in a perfect state, so that
ho might reach the female. The female, on the other hand,
might safely lose her organs for flying, swimming, or walking,
if she gradually acquired habits which rendered such powers
useless.
£We are, however, here concerned only with sexual selection.
This depends on the advantage which certain individuals have
over others of the same sex and species solely in respect of
reproduction! When, as in. the cases above mentioned, the two
sexes differ m structure in relation to different habits of life,
they have no doubt been modified through natural selection, and
by inheritance limited to one and the same sex. So again the
primary sexual organs, and those for nourishing or protecting the
young, come under the same influence ; for those individuals which
generated or nourished their offspring best, would leave, cceteris
paribus, the greatest number to inherit their superiority ; whilst
those which generated or nourished their offspring badly, would
leave but few to inherit their weaker powers. As the male has to
find the female, he requires organs of sense and locomotion, . nit
if these organs are necessary for the other purposes of life, && is
generally the case, they will have been developed through
natural selection. When the male has found the female, he
sometimes absolutely requires prehensile organs to hold her;
thus Dr. Wallace informs me that the males of certain moths
cannot unite with the females if their tarsi or feet are broken.
The males of many oceanic crustaceans, when adult, have their
legs and antennas modified in an extraordinary manner for the
prehension of the female ; hence we may suspect that it is be-
cause these, animals are washed about by the waves of the
open sea, that they require these organs in order to propagate
their kind, and if so, their development has been the result of
ordinary or natural selection. Some animals extremely low in
the scale have been modified for this same purpose ; thus the
males of certain parasitic worms, when fully grown, have the
lower surface of the terminal part of their bodies roughened
2 1 o The Descent of Man. Pa rt II
like a rasp, and with this they coil round and permanently hold
the females. 4
When the two sexes follow exactly the same nabits of life, and
the male has the sensory or locomotive organs more highly
developed than those of the female, it may be that the perfection
of these is indispensable to the male for finding the female ; but
in the vast majority of cases, they serve only to give one male
an advantage over another, for with sufficient time, the less well-
endowed males would succeed in pairing with the females ; and
judging from the structure of the female, they would be in all
other respects equally well adapted for their ordinary habits of
life. Since in such cases the males have acquired their present
structure, not from being better fitted to survive in the struggle
for existence, but from having gained an advantage over other
males, and from having transmitted this advantage to their male
offspring alone, sexual selection must here have come into action.
It was the importance of this distinction which led me to
designate this form of selection as Sexual Selection. So again,
if the chief service rendered to the male by his prehensile organs
is to prevent the escape of the female before the arrival of other
males, or when assaulted by them, these organs will have been
perfected through sexual selection, that is by the advantage
acquired by certain individuals over their rivals. But in most
cases of this kind it is impossible to distinguish between the
effects of natural and sexual selection. Whole chapters could
be filled with details on the differences between the sexes in their
sensory, locomotive, and prehensile organs. As, however, these
structures are not more interesting than others adapted for the
ordinary purposes of life I shall pass them over almost entirely,
giving only a few instances under each class.
There are many other structures and instincts which must
have been developed through sexual selection — such as the
weapons of offence and the means of defence of the males for
fighting with and driving away their rivals— their courage and
pugnacity — their various ornaments — their contrivances for pro-
4 M. Perrier advances this case claspers of certain male animals •
('Revue Scientifique,' Feb. 1, 1873, could not have been developed
p. 865) as one fatal to the belief in through the choice of the female !
sexual selection, inasmuch as he Had 1 not met with this remark, I
supposes that I attribute all the should not have thought it possible
differences between the sexes to for any one to have read this chapter
sexual selection. This distinguished and to have imagined that I main-
naturalist, therefore, like so many tain that the choice of the female
other Frenchmen, has not taken the had anything to do with the develop-
tiouble to understand even the first ment of the prehensile organs in the
pimciples of sexual selection. An male,
loglish naturalist insists that the
Chap. VIII. Sexual Selection. 211
ducing vocal or instrumental music — and their glands for
emitting odours, most of these latter structures serving only to
allure or excite the female. It is clear that these characters ara
the result of sexual and not of ordinary selection, since unarmed,
unornamented, or unattractive males would succeed equally well
in the battle for life and in leaving a numerous progeny, but for
the presence of better endowed males. We may infer that this
would be the case, because the females, which are unarmed and
unornamented, are able to survive and procreate their kind.
Secondary sexual characters of the kind just referred to, will be
fully discussed in the following chapters, as being in many
respects interesting, but especially as depending on the will,
choice, and rivalry en the individuals of either sex. When we
behold two males fighting for the possession of the female, or
several male birds displaying their gorgeous plumage, and per-
forming strange antics before an assembled body of females, we
cannot doubt that, though led by instinct, they know what they
are about, and consciously exert their mental and bodily powers.
Just as man can improve the breed of his game-cocks by the
selection of those birds which are victorious in the cockpit, so it
appears that the strongest and most vigorous males, or those
provided with the best weapons, have prevailed under nature,
and have led to the improvement of the natural breed or species.
A slight degree of variability leading to some advantage, how-
ever slight, in reiterated deadly contests would suffice for the
work of sexual selection; and it is certain that secondary sexual
characters are eminently variable. Just as man can give beauty,
according to his standard of taste, to his male poultry, or more
strictly can modify the beauty originally acquired by the parent
species, can give to the Sebright bantam a new and elegant
plumage, an erect and peculiar carriage — so it appears that
female birds in a state of nature, have by a long selection of the
more attractive males, added to their beauty or other attractive
qualities. No doubt this implies powers of discrimination and
taste on the part of the female which will at first appear
extremely improbable; but by the facts to be adduced here-
after, I hope to be able to shew that the females actually
have these powers. When, however, it is said that the lower
animals have a sense of beauty, it must not be supposed that
such sense is comparable with that of a cultivated man, with his
multiform and complex associated ideas. A more just com-
parison would be between the taste for the beautiful in animals,
and that in the lowest savages, who admire and deck themselves
with any brilliant, glittering, or curious object.
From our ignorance on several points, the precise manner in
v 2
2 1 2 The Descent of Man. Part 1L
which sexual selection acts is somewhat uncertain. Neverthe-
less if those naturalists who already believe in the mutability of
species, will read the following chapters, they will, I think, agree
with me, that sexual selection has played an important part in
the history of the organic world. It is certain that amongst
almost all animals there is a struggle between the males for the
possession of the female. This fact is so notorious that it would
be superfluous to give instances. Hence the females have tho
opportunity of selecting one out of several males, on the suppo-
sition that their mental capacity suffices for the exertion of a
choice. In many cases special circumstances tend to make the
struggle between the males particularly severe. Thus the males
of our migratory birds generally arrive at their places of breeding
before the females, so that many males are ready to contend for
each female. I am informed by Mr. Jenner Weir, that the bird-
catchers assert that this is invariably the case with the nightin-
gale and blackcap, and with respect to the latter he can himself
confirm the statement.
Mr. Swaysland of Brighton has been in the habit, during the
last forty years, of catching our migratory birds on their first
arrival, and he has never known the females of any species to
arrive before their males. During one spring he shot thirty -nine
males of Kay's wagtail (Budytes Raii) before he saw a single
female. Mr. Gould has ascertained by the dissection of those
snipes which arrive the first in this country, that the males come
before the females. And the like holds good with most of the
migratory birds of the United States. 5 The majority of the male
salmon in our rivers, on coming up from the sea, are ready to
breed before the females. So it appears to be with frogs and
toads. Throughout the great class of insects the males almost
always are the first to emerge from the pupal state, so that they
generally abound for a time before any females can be seen.*'
The cause of this difference between the males and females in
their periods of arrival and maturity is sufficiently obvious.
Those males which annually first migrated into any country, or
which in the spring were first ready to breed, or were the most
eager, would leave the largest number of offspring ; and these
5 J. A. Allen, on the 'Mammals rodite plants are dichogamons ; that
and Winter Birds of Florida,' Bull. is, their male and female organs are
<.*mp. Zoology, Harvard College, p. not ready at the same time, so that
268. they cannot be self-fertilised. Now
6 Even with those plants in which in such flowers, the pollen is in
the sexes are separate, the male -general matured before the stigma,
flowers are generally mature be- though there are exceptional cases
fore the female. As first shewn in which the female organs are
by C. K. Sprengel, many hermaph- beforehand.
Cha p, VIII. Sexual Selection.. 2 1 3
would tend to inherit similar instincts and constitutions. It
must be borne in mind that it would have been impossible to
change very materially the time of sexual maturity in the
females, without at the same time interfering with the period of
the production of the young — a period which must be determined
by the seasons of the year. On the whole there can be no doubt
that with almost all animals, in which the sexes are separate,
there is a constantly recurrent struggle between the males for
the possession of the females.
Our difficulty in regard to sexual selection lies in understand-
ing how it is that the males which conquer other males, or those
which prove the most attractive to the females, leave a greater
number of offspring to inherit their superiority than their
beaten and less attractive rivals. Unless this result does follow,
the characters which give to certain males an advantage over
others, could not be perfected and augmented through sexual
selection. When the sexes exist in exactly equal numbers, the
worst-endowed males will (except where polygamy prevails),
ultimately find females, and leave as many offspring, as well
fitted for their general habits of life, as the best-endowed males.
From various facts and considerations, I formerly inferred that
with most animals, in which secondary sexual characters are
well developed, the males considerably exceeded the females in
number; but this is not by any means always true. If the
males were to the females as two to one, or as three to two, or
oven in a somewhat lower ratio, the whole affair would be
simple; for the better-armed or more attractive males would
leave the largest number of offspring. But after investigating,
as far as possible/the numerical proportion of the sexes, I do not
believe that any great inequality in number commonly exists.
In most cases sexual selection appears to have been effective in
the following manner.
Let us take any species, a bird for instance, and divide the
females inhabiting a district into two equal bodies, the one
consisting of the more vigorous and better-nourished individuals,
and the other of the less vigorous and healthy. The former,
there can be little doubt, would be ready to breed in the spring
before the others ; and this is the opinion of Mr. Jenner Weir,
who has carefully attended to the habits of birds during many
years. (Jthere can also be no doubt that the most vigorous,
best-nourished and earliest breeders would on an average
succeed in rearing the largest number of fine offspring. 7 The
males, as we have seen, are generally ready to breed before the
7 Here is excellent evidence on an ' experienced ornithologist. Mr.
the character of the offspring from J. A. Allen, in speaking (' Mammals
214 The Descent of Man. Paut tl
females ; the strongest, and with some species the best armed of
the males, drive away the weaker ; and the former would then
unite with the more vigorous and better-nourished females, be-
cause they are the first to breed. 8 Such vigorous pairs would
surely rear a larger number of offspring^than the retarded
females, which would be compelled to unite with the conquered
and less powerful males, supposing the sexes to be numerically
equal ; and this is all that is wanted to add, in the course of
successive generations, to the size, strength and courage of the
males, or to improve their weapons."^
But in very many cases the males which conquer their rivals,
do not obtain possession of the females, independently of the
choice of the latter. The courtship of animals is by no means
so simple and short an affair as might be thought. The
females are most excited by, or prefer pairing with, the more
ornamented males, or those which* are the best songsters, or play
the best antics; but it is obviously probable that they would
at the same time prefer the more vigorous and lively males, and
this has in some cases been confirmed by actual observation.*
Thus the more vigorous females, which are the first to breed, will
have the choice of many males ; and though they may not always
select the strongest or best armed, they will select those which
are vigorous and well armed, and in other respects the most at-
tractive. Both sexes, therefore, of such early pairs would as above
explained, have an advantage over others in rearing offspring ; and
this apparently has sufficed during a long course of generations
to add not only to the strength and fighting powers of the males,
but likewise to their various ornaments or other attractions.
In the converse and much rarer case of the males selecting
particular females, it is plain that those which were the most
vigorous and had conquered others, would have the freest
choice ; and it is almost certain that they would select vigorous
as well as attractive females. Such pairs would have an advan-
and Winter Birds of E. Florida/ to those female bees which are the
p. 229) of the later broods, after the first to emerge from the pupa each
accidental destruction of the first, year. See his remarkable essay,
says, that these " are found to be 'Anwendung den Darwin'schen Lehre
" smaller and paler-coloured than auf Bienen/ * Verh. d. V. Jahrg.'
*' those hatched earlier in the sea- xxix. p. 45.
** son. In cases where several broods 9 With respect to poultry, I have
*' are i eared each year, as a general received information, hereafter to
" rule the birds of the earlier broods be given, to this effect, fcven with
" seem in all respects the most per- birds, such as pigeons, which pair
M feet and vigorous." for life, the female, as I hear from
8 Hermann Mtiller has come to Mr. Jenner Weir, will desert her
this same conclusion with respect mate if he is injured or grows weak,
t'iJAP. Vlll. Sexual Selection. 215
tago in rearing offspring, more especially if the male had the
power to defend the female during the pairing-season as occurs
with some of the higher animals, or aided her in providing for
the yoimg. The same principles would apply if each sex pre-
ferred acid selected certain individuals of the opposite sex;
supposing taat they selected not only the more attractive, but
likewise the more vigorous individuals.
Numerical Proportion of the Two Sexes.— I have remarked that
sexual selection would be a simple affair if the males were con-
siderably more numerous than the females. Hence I was led to
investigate, as far as I could, the proportions between the two
sexes of as many animals as possible; but the materials are.
scanty. I will here give only a brief abstract of the results,
retaining the details for a supplementary discussion, so as not
to interfere with the course of my argument. Domesticated
animals alone afford the means of ascertaining the propor-
tional numbers at birth; but no records have been specially'
kept for this purpose. By indirect means, however, I have
collected a considerable body of statistics, from which it appears
that with most of our domestic animals the sexes are nearly
equal at birth. Thus 25,560 births of race-horses have been
recorded during twenty-one years, and the male births were
to the female births as 99*7 to 100. In greyhounds the in-
equality is greater than with any other animal, for out of 6878
births during twelve years, the male births were to the female
as 110*1 to 100. It is, however, in some degree doubtful
whether it is safe to infer that the proportion would be the same
under natural conditions as under domestication ; for slight and
unknown differences in the conditions affect the proportion of
the sexes. Thus with mankind, the male births in England
are as 104*5, in Russia as 108*9, and with the Jews of Livonia as
120, to 100 female births. But I shall recur to this curious point
of the excess of male births in the supplement to this chapter. At
the Cape of Good Hope, however, male children of European
extraction have been born during several years in the proportion
of between 90 and 99 to 100 female children.
For our present purpose we are concerned with the proportion
of the sexes, not only at birth, but also at maturity, and this
adds another element of doubt ; for it is a well-ascertained fact
that with man the number of males dying before or during birth,
and during the first few years of infancy, is considerably larger
than that of females. So it almost certainly is with male lambs,
and probably with some other animals. The males of some species
kill one another by fighting; or they drive one another about
2 i 6 The Descent of Man. Part II.
until they become greatly emaciated. They must -also be often
exposed to various dangers, whilst wandering about in eager
search for the females. In many kinds of fish the males are
much smaller than the females, and they are believed often to be
devoured by the latter, or by other fishes. The females of
some birds appear to die earlier than the males; they arc
also liable to be destroyed on their nests, or whilst in charge
of their young. With insects the female larvae are often larger
than those of the males, and would consequently be more likely
to be devoured. In some cases the mature females are less
active and less rapid in their movements than the males, and
could not escape so well from danger. Hence, with animals in a
state of nature, we must rely on mere estimation, in order to
judge of the proportions of the sexes at maturity ; and this is
but little trustworthy, except when the inequality is strongly
marked. Nevertheless, as far as a judgment can be formed, we
may conclude from the facts given in the supplement, that the
'males of some few mammals, of many birds, of some fish and
insects, are considerably more numerous than the females.
The proportion between the sexes fluctuates slightly during
successive years : thus with race-horses, for every 100 mares born
the stallions varied from 107*1 in one year to 92'6 in another year,
and with greyhounds from 116*3 to 95*3. But had larger num-
bers been tabulated throughout an area more extensive than
England, these fluctuations would probably have disappeared;
and such as they are, would hardly suffice to lead to effective
sexual selection in a state of nature. Nevertheless, in the cases
of some few wild animals, as shewn in the supplement, the
proportions seem to fluctuate either during different seasons
or in different localities in a sufficient degree to lead to such
selection. For it should be observed that any advantage,
gained during certain years or in certain localities by those males
which were able to conquer their rivals, or were the most
attractive to the females, would probably be transmitted to the
offspring, and would not subsequently be eliminated. During
the succeeding seasons, when, from the equality of the sexes,
every male was able to procure a. female, the stronger or more at-
tractive males previously produced would still have at least as
^ood a chance of leaving offspring as the weaker or less attractive.
Polygamy, — The practice of polygamy leads to the same results
as would follow from an actual inequality in the number of the
sexes ; for if each male secures two or more females, many males
cannot pair ; and the latter assuredly will be the weaker or less
attractive individuals. Many mammals and some few birds ar«>
Chap. VII L Sexual Selection, 217
polygamous, but with animals belonging to the lower classes 1
have found no evidence of this habit. The intellectual powers
of such animals are, perhaps, not sufficient to lead them to
collect and guard a harem of females. That some relation exists
between polygamy and the development of secondary sexual
characters, appears nearly certain ; and this supports the view
that a numerical preponderance of males would be eminently
favourable to the action of sexual selection. Nevertheless many
animals, which are strictly monogamous, especially birds, display
Strongly-marked secondary sexual characters ; whilst some few
animals, which are polygamous, do not have such characters.
We will first briefly run through the mammals, and then tun;
to birds. The gorilla seems to be polygamous, and the male
differs considerably from fhe female ; so it is with some baboons,
which live in herds containing twice as many adult females as
males. In South America the Mycetes car ay a presents well-
marked sexual differences, in colour, beard, and vocal organs ;
and the male generally lives with two or three wives: the male
of the Cebus capucinus differs somewhat from the female, and
appears to be polygamous. 10 Little is known on this head with
respect to most other monkeys, but some species are strictly
monogamous. The ruminants are eminently polygamous, and
they present sexual differences more frequently than almost any
other group of mammals; this holds good, especially in their
weapons, but also in other characters. Most deer, cattle, and
sheep are polygamous; as are most antelopes, though some are
monogamous. Sir Andrew Smith, in speaking of the antelopes
of South Africa, says that in herds of about a dozen there was
rarely more than one mature male. The Asiatic Aniilope saiga
appears to be the most inordinate polygamist in the world ; for
Pallas 11 states that the male drives away all rivals, and collects a
herd of about a hundred females and kids together ; the female
is hornless and has softer hair, but does not otherwise differ
much from the male. The wild horse of the Falkland Islands and
of the Western States of N. America is polygamous, but, except
in his greater size and in the proportions of his body, differs but
little from the mare. The wild boar presents well-marked sexual
10 On the Gorilla, Savage and Fasc. xii. 1777, p. 29. Sir Andrew
Wyman * Boston Journal of Nat. Smith, * Illustrations of the Zoology
Hist.' vol. v. 1845-47, p. 423. On of S. Africa/ 1849, pi. 29, on the
Cynocephalus, Brehm, * Illust. Thier- Kobus. Owen, in his ' Anatomy of
leben,' B. i. 1864, s. 77. On My- Vertebrates ' (vol. iii. 1868, p. 633)
cetes, Rengger, 'Naturgesch.: Sauge- gives a table shewing incidentally
thiere von Paraguay,' 1830, s. 14, which species of antelopes are gre-
2Q. Cebus, Brehm, ibid. s. 108. garious.
11 Pallas, 'Spicilegia Zoolog.,
2 1 8 The Descent of Man. i'art LI,
characters, in his great tusks and some other points. In Europe
and in India he leads a solitary life, except during the breeding-
season ; but as is believed by Sir W. Elliot, who has had many
opportunities in India of observing this animal, he consorts at
this season with several females. Whether this holds good
in Europe is doubtful, but it is supported by some evidence.
The adult male Indian elephant, like the boar, passes much of
his time in solitude ; but as Dr. Campbell states, when with
others, " it is rare to find more than one male with a whole herd
" of females ;" the larger males expelling or killing the smaller
and weaker ones. The male differs from the female in his immense
tusks, greater size, strength, and endurance; so great is the
difference in these respects, that the males when caught are
valued at one-fifth more than the females. 12 The sexes of other
pachydermatous animals differ very little or not at all, and, as
far as known, they are not polygamists. Nor have I heard of any
species in the Orders of Cheiroptera, Edentata, Insectivora and
Bodents being polygamous, excepting that amongst the Rodents,
the common rat, according to some rat-catchers, lives with several
females. Nevertheless the two sexes of some sloths (Edentata)
differ in the character and colour of certain patches of hair on
their shoulders. 13 And many kinds of bats (Cheiroptera) present
well-marked sexual differences, chiefly in the males possessing
odoriferous glands and pouches, and by their being of a lighter
colour. 14 In the great order of Eodents, as far as I can learn,
the sexes rarely differ, and when they do so, it is but slightly in
the tint of the fur.
As I hear from Sir Andrew Smith, the lion in South Africa
sometimes lives with a single female, but generally with more,
and, in one case, was found with as many as five females ; so
that he is polygamous. As far as I can discover, he is the only
polygamist amongst all the terrestrial Carnivora, and he alone
presents well-marked sexual characters. If, however, we turn
to the marine Carnivora, as we shall hereafter see, the case is
widely different ; for many species of seals offer extraordinary
sexual differences, and they are eminently polygamous. Thus,
according to Peron, the male sea-elephant of the Southern Ocean
always possesses several females, and the sea-lion of Forster is
said to be surrounded by from twenty to thirty females. In the
North, the male sea-bear of Steller is accompanied by even a
12 Dr. Campbell, in * ?roc. Zoo- 1S Dr. Gray, in ' Annals an J
log. Soc.' 1869, p. 138, See also an Mag. of Nat. Hist.' 1871, p. 302.
interesting paper, by Lieut. Johii- 14 See Dr. Dobson's excellent
stone, in ' Proc. Asiati' Soc. of paper, in * Proc. Zoolog. Soc/ 1S73.
Bengal/ May. 1868. p. 241.
Chap. \ ill. Sexual Selection. 2ig
greater number of females. It is an interesting fact, as Dr.
Gill remarks, 15 that in the monogamous species, "or those
u living in small communities, there is little difference in size
" between the males and females ; in the social species, or rather
* those of which the males have harems, the males are vastly
" larger than the females."
Amongst birds, many species, the sexes of which differ greatly
from each other, are certainly monogamous. In Great Britain
we see well-marked sexual differences, for instance, in the wild-
duck which pairs with a single female, the common blackbird,
and the bullfinch which is said to pair for life. . I am informed
by Mr. Wallace that the like is true of the Chatterers or
Cotingidae of South America, and of many other birds. In several
groups I have not been able to discover whether the species are
polygamous or monogamous.. Lesson says that birds of paradise,
so remarkable for their sexual differences, are polygamous, but Mr.
Wallace doubts whether he had sufficient evidence. Mr. Salvia
tells me he has been led to believe that humming-birds are
polygamous. The male widow-bird, remarkable for his caudal
plumes, certainly seems to be a polygamist. 16 I have been
assured by Mr. Jenner Weir and by others, that it is somewhat
common for three starlings to frequent the same nest; but
whether this is a case of polygamy or polyandry has not been
ascertained.
The Gallinaceae exhibit almost as strongly marked sexual
differences as birds of paradise or humming-birds, and many of
the species are, as is well known, polygamous; others being
strictly monogamous. What a contrast is presented between the
sexes of the polygamous peacock or pheasant, and the mono-
gamous guinea-fowl or partridge ! Many similar cases could be
given, as in the grouse tribe, in which the males of the poly-
gamous capercailzie and black-cock differ greatly from the
females ; whilst the sexes of the monogamous red grouse and
ptarmigan differ very little. In the Cursores, except amongst
the bustards, few species offer strongly-marked sexual dif-
ferences, and the great bustard (Otis tarda) is said to be poly-
gamous. With the Grallatores, extremely few species differ
sexually, but the ruff (Machetes jpugnax) affords a marked
15 The Eared Seals, « American Great Bustard, see L. Lloyd, 'Game
Naturalist,' vol. iv., Jan. 1871. Birds of Sweden,' 1867, p. 19, and
16 ' The Ibis,' vol. iii. 1861 p. 182. Montagu and Selby speak of
133, on the Progne Widow-bird. the Black Grov.«e as polygamous
See also on the Vidua axillaris^ and of the Red Grouse as mono-
ibid. vol. ii. 1860, p. 211. On the gamous.
polygamy of the Capercailzie and
220 The Descent of Man, Part II.
exception, and this species is believed by Montagu to be a
polygamist. Hence it appears that amongst birds there often
exists a close relation between polygamy and the development of
strongly-marked sexual differences. I asked Mr. Bartlett, of the
Zoological Gardens, who has had very large experience with
birds, whether the male tragopan (one of the Gallinaceae) was
polygamous, and I was struck by his answering, "I do not
" know, but should think so from his splendid colours."
It deserves notice that the instinct of pairing with a single
female is easily lost under domestication. The wild-duck is
strictly monogamous, the domestic-duck highly polygamous.
The Kev. W. D. Fox informs me that out of some half-tamed
wild-ducks, on a large pond in his neighbourhood, so many
mallards were shot by the gamekeeper that only one was left for
every seven or eight females ; yet unusually large broods were
reared. The guinea-fowl is strictly monogamous ; but Mr. Fox
finds that his birds succeed best when he keeps one cock to two
or three hens. Canary-birds pair in a state of nature, but the
breeders in England successfully put one male to four or five
females. I have noticed these cases, as rendering it probable
that wild monogamous species might readily become either
temporarily or permanently polygamous.
Too little is known of the habits of reptiles and fishes to enable
us to speak of their marriage arrangements. The stickle-back
(Gasterosteus), however, is said to be a polygamist; 17 and the
male during the breeding season differs conspicuously from the
female.
To sum up on the means through which, as far as we can
judge, sexual selection has led to the development of secondary
sexual characters. It has been shewn that the largest number
of vigorous offspring will be reared from the pairing of the
strongest and best-armed males, victorious in contests over
other males, with the most vigorous and best-nourished females,
which are the first to breed in the spring. If such females select
the more attractive, and at the same time vigorous males, they
will rear a larger number of offspring than the retarded females,
which must pair with the less vigorous and less attractive
males. So it will be if the more vigorous males select the more
attractive and at the same time healthy and vigorous females ;
and this will especially hold good if the male defends the
female, and aids in providing food for the young. The ad-
vantage thus gained by the more vigorous pairs in rearing a
larger number of offspring has apparently sufficed to render
sexual selection efficient. But a large numerical preponderance
17 Ncel Humphreys, < River Gardens/ 1857.
Chap. VIII. Sexual Selection. 221
of males over females will be still more efficient ; whether the
preponderance is only occasional and local, or permanent;
whether it occurs at birth, or afterwards from the greater de-
struction of the females ; or whether it indirectly follows from
the practice of polygamy.
The Male generally more modified than the Female. — Throughout
the animal kingdom, when the sexes differ in external appearance,
it is, with rare exceptions, the male which has been the more
modified ; for, generally, the female retains a closer resemblance
to the young of her own species, and to other adult members of
the same group. £lhe cause of this seems to lie in the males
of almost all animals having stronger passions than the females]
Hence it is the males that fight together and sedulously display
their charms before the females ; and the victors transmit their
superiority to their male ofifspringj Why both sexes do not thus
acquire the characters of their fathers, will be considered here-
after. That the males of all mammals eagerly pursue the
females is notorious to every one. So it is with birds ; but many
cock birds do not so much pursue the hen, as display their
plumage, perform strange antics, and pour forth their song in
her presence. The male in the few fish observed seems much
more eager than the female ; and the same is true of alligators,
and apparently of Batrachians. Throughout the enormous class of
insects, as Kirby remarks, 18 " the law is, that the male shall seek
" the female." Two good authorities, Mr. Blackwall and Mr. C.
Spence Bate, tell me that the males of spiders and crustaceans
are more active and more erratic in their habits than the females.
When the organs of sense or locomotion are present in the one
sex of insects and crustaceans and absent in the other, .or when,
as is frequently the case, they are more highly developed in the
one than in the other, it is, as far as I can discover, almost
invariably the male which retains such organs, or has them most
developed ; and this shews that the male is the more active
member in the courtship of the sexes. 19
18 Kirby and Spence, ' Introduc- females of this species are impreg-
tion to Entomology/ vol. iii. 1826, nated by the males which are born
p. 342. in the same cells with them ; but
19 One parasitic Hymenopterous it is much more probable that the
insect (Westwood, ' Modern Class, of females visit other cells, so that
Insects/ vol. ii. p. 160) forms an close interbreeding is thus avoided,
exception to the rul*, as the male We shall hereafter meet in various
has rudimentary wings, and never classes, with a few exceptional eises,
quits the cell in which it is born, in which the female, instead of the
whilst the female has well-developed male, is the seeker and wooer,
wings. Audouin believes that the
222 The Descent of Man. Part II.
The female, on the other hand, with the rarest exceptions, is
less eager than the male. As the illustrious Hunter w long ago
observed, she generally " requires to be courted ;" she is coy, and
may often be seen endeavouring for a long time to escape from
the male. Every observer of the habits of animals will be able
to call to mind instances of this kind. It is shown by various
facts, given hereafter, and by the results fairly attributable to
sexual selection, that the female, though comparatively passive,
generally exerts some choice and accepts one male in preference
to others. Or she may accept, as appearances would sometimes
lead us to believe, not the male which is the most attractive to
her, but the one which is the least distasteful. The exertion of
some choice on the part of the female seems a law almost as
general as the eagerness of the male.
We are naturally led to enquire why the male, in so many and
such distinct classes, has become more eager than the female, so
that he searches for her, and plays the more active part in court-
ship. It would be no advantage and some loss of power if each
sex searched for the other; but why should the male almost
always be the seeker? The ovules of plants after fertili-
sation have to be nourished for a time; hence the pollen is
necessarily brought to the female organs— being placed on the
stigma, by means of insects or the wind, or by the spontaneous
movements of the stamens ; and in the Algae, &c, by the loco-
motive power of the antherozooids. With lowly-organised
aquatic animals, permanently affixed to the same spot and having
their sexes separate, the male element is invariably brought to
the female ; and of this we can see the reason, for even if the
ova were detached before fertilisation, and did not require
subsequent nourishment or protection, there would yet be greater
difficulty in transporting them than the male element, because,
being larger than the latter, they are produced in far smaller
numbers. So that many of the lower animals are, in this re-
spect, analogous with plants. 21 The males of affixed and aquatic
animals having been led to emit their fertilising element in
this way, it is natural that any of their descendants, which
rose in the scale and became locomotive, should retain the same
habit ; and they would approach the female as closely as pos-
sible, in order not to risk the loss of the fertilising element in a
long passage of it through the water. With some few of the lower
20 { Essays and Observations.* of the male and female reproductive
edited by Owen, vol. i. 1861, r. cells, remarks, " verh'alt sich die
194. u erne bei der Vereinigung activ,
21 Prof. Sachs (' Lehrbuch de.- "... die andere erscheint bei del
Botanik/ 1870, s. 633) in speaking " Vereinigung passiv."
Chap. VIII. Sexual Selection. 223
animals, the females alone are fixed, and the males of these must
be the seekers. But it is difficult to understand why the males of
species, of which the progenitors were primordially free, should
invariably have acquired the habit of approaching the females,
instead of being approached by them. But in all cases, in order
that the males should seek efficiently, it would be necessary that
they should be endowed with strong passions; and the acquire-
ment of such passions would naturally follow from the more
eager leaving a larger number of offspring than the less eager.
The great eagerness of the males has thus indirectly led to their
much more frequently developing secondary sexual characters
than the females. But the development of such characters
would be much aided, if the males were more liable to vary than
the females — as I concluded they were — after a long study of
domesticated animals. Von Nathusius, who has had very wide
experience, is strongly of the same opinion. 22 Good evidence also
in favour of this conclusion can be produced by a comparison
of the two sexes in mankind. During the Novara Expedition 2S
a vast number of measurements was made of various parts of the
body in different races, and the*men were found in almost every
case to present a greater range of variation than the women ; but I
shall have to recur to this subject in a future chapter. Mr. J.
Wood, 24 who has carefully attended to the variation of the muscles
in man, puts in italics the conclusion that " the greatest number of
*' abnormalities in each subject is found in the males." He had
previously remarked that ''altogether in 102 subjects, the varieties
" of redundancy were found to be half as many again as in
" females, contrasting widely with the greater frequency of
" deficiency in females before described." Professor Macalister
likewise remarks ^ that variations in the muscles " are probably
" more common in males than females." Certain muscles which
are not normally present in mankind are also more frequently
developed in the male than in the female sex, although exceptions
to this rule are said to occur. Dr. Burt Wilder 26 has tabulated
the cases of 152 individuals with supernumerary digits, of which
86 were males, and 39, or less than half, females, the remaining
27 being of unknown sex. It should not, however, be overlooked
22 * Vortrage Uber Viehzucht,* my « Variation of Animals and
1872, p. 63. Plants under Domestication,' vol, ii.
23 < Reise der Novara: Anthro- 1868, p. 75.
polog. Theil,' 1867, s. 216-269. 24 c Proceedings Royal Soc.' vol.
The results were calculated by Dr. xvi. July 1868, pp. 519 and 524.
Weisbach from measuiements made 25 <Proc Royal Irish Academy,
by Drs. K. Scherzer and Schwarz. vol. x. 1868, p. 123
On the greater variability of the 26 * Massachusetts Medical Soc
piales of domesticated animals, see vol. ii. No. 3, 1868, p. 9.
224 The Descent of Man, Part II.
that women would more frequently endeavour to conceal a
deformity of this kind than men. Again, Dr. L. Meyer asserts that
the ears of man are more variable in form than those of woman. 2 *
Lastly the temperature is more variable in man than in woman. 28
The cause of the greater general variability in the male sex,
than in the female is unknown, except in so far as secondary
sexual characters are extraordinarily variable, and are usually
confined to the males ; and, as we shall presently see, this fact is
to a certain extent, intelligible. Through the action of sexual
and natural selection male animals have been rendered in very
many instances widely different from their females; but in-
dependently of selection the two sexes, from differing constitu-
tionally, tend to vary in a somewhat different manner. The
female has to expend much organic matter in the formation of
her ova, whereas the male expends much force in fierce contests
with his rivals, in wandering about in search of the female, in
exerting his voice, pouring out odoriferous secretions, &c. : and
this expenditure is generally concentrated within a short period.
The great vigour of the male during the season of love seems
often to intensify his colours, independently of any marked dif-
ference from the female. 29 In mankind, and even as low down
in the organic scale as in the Lepidoptera,, the temperature of the
body is higher in the male than in the female, accompanied in the
case of man by a slower pulse. 30 On the whole the expenditure
of matter and force by the two sexes is probably nearly equal,
though effected in very different ways and at different rates.
From the causes just specified the two sexes can hardly fail to
differ somewhat in constitution, at least during the breeding
season; and, although they may be subjected to exactly the
same conditions, they will tend to vary in a different manner.
If such variations are of no service to either sex, they will not be
accumulated and increased by sexual or natural selection. Never-
theless, they may become permanent if the exciting cause act&
27 'Arehiv fur Path. Anat. und and retention by them of the sperm -
Phys.' 1871, p. 488. atic fluid; but this can hardly be
28 The conclusions recently ar- the case ; for many male birds, for
rived at by Dr. J. Stockton Hough, instance young pheasants, become
on the temperature of man, are brightly coloured in the autumn of
given in the * Pop. Science Review,' their first year.
Jan. 1st, 1874, p. 97. 30 For mankind, see Dr. J. Stock-
29 Prof. Mantegazza is inclined ton Hough, whose conclusions art:
to believe (* Letter a a Carlo Darwin,' given in the l Pop. Science Review,'
* Archivio per 1' Anthr opologia,* 1874, p. 97. See Girard's observa-
1871, p. 306) that the bright tions on the Lepidoptera, as gives
colours, common in so many male in the ' Zoological Record,' 1869, p.
animals, are due to the presence 347.
Chap. VIII. Sexual Selection. 225
permanently ; and in accordance with a frequent tbrm of inheri-
tance they may be transmitted to that sex alone in which they
first appeared. In this case the two sexes will come to present
permanent, yet unimportant, differences of character. For
instance, Mr. Allen shews that with a large number of birds
inhabiting the northern and southern United States, the speci*
mens from the south are darker-coloured than those from the
north ; and this seems to be the direct result of the difference in
temperature, light, &c, between the two regions. Now, in some
few cases, the two sexes of the same species appear to have been
differently affected ; in the Agelceus phceniceics the males have had
their colours greatly intensified in the south; whereas with Car-
dinalis virginianus it is the females which have been thus affected ;
with Quiscalus major the females have been rendered extremely
variable in tint, whilst the males remain nearly uniform. 81
A few exceptional cases occur in various classes of animals, in
which the females instead of the males have acquired well
pronounced secondary sexual characters, such as brighter colours,
greater size, strength, or pugnacity. With birds there has some-
times been a complete transposition of the ordinary characters
proper to each sex ; the females having become the more eager
in courtship, the males remaining comparatively passive, but
apparently selecting the more attractive females, as we may infer
from the results. Certain hen birds have thus been rendered
more highly coloured or otherwise ornamented, as well as more
powerful and pugnacious than the cocks ; these characters being
transmitted to the female offspring alone.
It may be suggested that in some cases a double process of
selection has been carried on; that the males have selected
the more attractive females, and the latter the more attractive
males. This process, however, though it might lead to the
modification of both sexes, would not make the one sex
different from the other, unless indeed their tastes for the beauti-
ful differed ; but this is a supposition too improbable to be worth
considering in the case of any animal, excepting man. There
are, however, many animals in which the sexes resemble each
other, both being furnished with the same ornaments, which
analogy would lead us to attribute to the agency of sexual
selection. In such cases it may be suggested with more plausi-
bility, that there has been a double or mutual process of sexual'
selection ; the more vigorous and precocious females selecting
the more attractive and vigorous males, the latter rejecting all
except the more attractive females. But from what we know
« « Mammals and Bir& of & Florida,' pp. 234, 280, 295.
226 The Descent of Man. Pari II
of the habits of animals, this view is hardly probable, for the
male is generally eager to pair with any female. It is more
probable that the ornaments common to both sexes were acquire^
by one sex, generally the male, and then transmitted to the oft-
spring of both sexes. If, indeed, during a lengthened period the
males of any species were greatly to exceed the females in
mmber, and then during another lengthened period, but under
different conditions, the reverse were to occur, a double, but
not simultaneous, process of sexual selection might easily be
carried on, by which the two sexes might be rendered widely
different.
We shall hereafter see that many animals exist, of which
neither sex is brilliantly coloured or provided with special orna-
ments, and yet the members of both sexes or of one alone have
probably acquired simple colours, such as white or black, through
sexual selection. The absence of bright tints or other ornaments
may be the result of variations of the right kind never having
occurred, or of the animals themselves having preferred plain
black or white. Obscure tints have often been developed
through natural selection for the sake of protection, and the
acquirement through sexual selection of conspicuous colours,
appears to have been sometimes checked from the danger thus
incurred. But in other cases the males during long ages may
have struggled together for the possession of the females, and
yet no effect will have been produced, unless a larger number of
offspring were left by the more successful males to inherit their
superiority, than by the less successful : and this, as previously
shewn, depends on many complex contingencies.
Sexual selection acts in a less rigorous manner than natural
selection. The latter produces its effects by the life or death at
all ages of the more or less successful individuals. Death, indeed,
not rarely ensues from the conflicts of rival males. But generally
the less successful male merely fails to obtain a female, or obtains a
retarded and less vigorous female later in the season, or, if poly-
gamous, obtains fewer females ; so that they leave fewer, less vigor-
ous, or no offspring. In regard to structures acquired through
ordinary or natural selection, there is in most cases, as long as the
conditions of life remain the same, a limit to the amount of
advantageous modification in relation to certain special purposes ;
but in regard to structures adapted to make one male victorious
over another, either in fighting or in charming the female, there
is no definite limit to the amount of advantageous modification ;
so that as long as the proper variations arise the work of sexual
selection will go on. This circumstance may partly account for
the frequent and extraordinary amount of variability presented
Ch^p. VIII. Sexual Selection. 227
by secondary sexual characters. Nevertheless, natural selectiofi
■will determine that such characters shall not be acquired by the
■victorious males, if they would be highly injurious, either by
expending too much of their vital powers, or by exposing them
to any great danger. The development, however, of certain
structures — of the horns, for instance, in certain stags — has been
carried to a wonderful extreme ; and in some cases to an extreme
which, as far as the general conditions of life are concerned,
must be slightly injurious to the male. From this fact we learn
that the advantages which favoured males derive from conquer-
ing other males in battle or courtship, and thus leaving a
numerous progeny, are in the long run greater than those derived
from rather more perfect adaptation to their conditions of life.
We shall further see, and it could never have been anticipated,
that the power to charm the female has sometimes been more
important than the power to conquer other males in battle.
LAWS OP INHERITANCE.
In order to understand how sexual selection has acted on many
animals of many classes, and in the course of ages has produced
a conspicuous result, it is necessary to bear in mind the laws of
inheritance, as far as they are known. Two distinct elements
are included under the term " inheritance " — the transmission,
and the development of characters; but as these generally go
together, the distinction is often overlooked. We see this dis-
tinction in those characters which are transmitted through
the early years of life, but are developed only at maturity
or during old age. We seethe same distinction more clearly
with secondary sexual characters, for these are transmitted
through both sexes, though developed in one alone. That they
are present in both sexes, is manifest when two species, having
strongly-marked sexual characters, are crossed, for each trans-
mits the characters proper to its own male and female sex to tho
hybrid offspring of either sex. The same fact is likewise mani-
fest, when characters proper to the male are occasionally deve-
loped in the female when she grows old or becomes diseased,
as, for instance, when the common hen assumes the flowing tail-
feathers, hackles, comb, spurs, voice, and even pugnacity of the
cock. Conversely, the same thing is evident, more or less plainly,
with castrated mal es. Again, independently of old age or disease,
characters are occasionally transferred from the male to the
female, as when, in certain breeds of the fowl, spurs regularly
appear in the young and healthy females. But in truth they are
pimply developed in tiic female ; for in every breed each detail
2
228 The Descent of Man, Part IX
in the structure of the spur is transmitted through the female
to her male offspring. Many cases will hereafter be given, where
the female exhibits, more or less perfectly, characters proper to
the male, in whom they must have been first developed, and then
transferred to the female. The converse case of the first de-
velopment of characters in the female and of transference to the
male, is less frequent ; it will therefore be well to give one strik-
ing instance. With bees the pollen-collecting apparatus is used
by the female alone for gathering pollen for the larvae, yet in
most of the species it is partially developed in the males
to whom it is quite useless, and it is perfectly developed
in the males of Bombus or the humble-bee. 32 As not a
single other Hymenopterous insect, not even the wasp, which is
closely allied to the bee, is provided with a pollen-collecting
apparatus, we have no grounds for supposing that male bees
primordially collected pollen as well as the females ; although
we have some reason to suspect that male mammals primordially
suckled their young as well as the females. Lastly, in all cases of
reversion, characters are transmitted through two, three, or many
more generations, and are then developed under certain unknown
favourable conditions. This important distinction between
transmission and development will be best kept in mind by the
aid of the hypothesis of pangenesis. According to this hypothesis,
every unit or cell of the body throws off gemmules or undeveloped
atoms, which are transmitted to the offspring of both sexes, and
are multiplied by self-division. They may remain undeveloped
during the early years of life or during successive generations;
and their development into units or cells, like those from which
they were derived, depends on their affinity for, and union
with other units or cells previously developed in the due order
of growth.
Inheritance at corresponding Periods of Life. — This tendency
is well established. A new character, appearing in a young
animal, whether it lasts throughout life or is only transient, will,
in general, reappear in the offspring at the same age and last
for the same time. If, on the other hand, a new character
appears at maturity, or even during old age, it tends to re-
appear in the offspring at the same advanced age. When devia-
tions from this rule occur, the transmitted characters much
oftener appear before, than after the corresponding age. As 1
have dwelt on this subject sufficiently in another work, 33 1 will
32 H. Miiller, * Anwendung der S3 * The Variation of Animals
Darwin'schen Lehre/ &c. Verfr. and Plants under Domestication,'
d, n. V. Jahrg, xsis. p. 4%, vol. ii. 1868, p. 75. In th* la*i
Ohap. VJTT. Sexual Selection. 22g
here merely give two or three instances, for the sake of recalling
the subject to the reader's mind. In several breeds of the Fowl,
the down-covered chickens, the young birds in their first true
plumage, and the adults differ greatly from one another, as well
as from their common parent-form, the Gallus lankiva; and
these characters are faithfully transmitted by each breed to their
offspring at the corresponding periods of life. For instance, the
chickens of spangled Hamburgs, whilst covered with down, have
a few dark spots on the head and rump, but are not striped
longitudinally, as in many other breeds ; in their first true plu-
mage, " they are beautifully pencilled," that is each feather is
transversely marked by numerous dark bars ; but in their second
plumage the feathers all become spangled or tipped with a dark
round spot 34 Hence in this breed variations have occurred at,
and been transmitted to, three distinct periods of life. The
Pigeon offers a more remarkable case, because the aboriginal
parent species does not undergo any change of plumage with
advancing age, excepting that at maturity the breast becomes
more iridescent ; yet there are breeds which do not acquire their
characteristic colours until they have moulted two, three, or
four times; and these modifications of plumage are regularly
transmitted.
Inheritance at corresponding Seasons of the Tear. — With animals
in a state of nature, innumerable instances occur of characters
appearing periodically at different seasons. We see this in the
horns of the stag, and in the fur of arctic animals which becomes
thick and white during the winter. Many birds acquire bright
colours and other decorations during the breeding-season alone.
Pallas states, 85 that in Siberia domestic cattle and horses become
lighter-coloured during the winter; and I have myself observed,
and heard of similar strongly marked changes of colour, that is,
from brownish cream-colour or reddish-brown to a perfect white,
in several ponies in England. Although I do not know that this
tendency to change the colour of the coat during different seasons
chapter but one, the provisional mals/ &c, vol. i. pp. 160, 249 ;
hypothesis of pangenesis, above vol. ii. p. 77.
alluded to, is fully explained. 35 * Novae species Quadrupeduin e
84 These facts are given on the Glirium ordine,' 1778, p. 7. On
high authority of a great breeder, the transmission of colour by the
Mr. Teebay ; see Tegetraeier's * Poul- horse, see * Variation of Animals,
try Book/ 1868, p. 158. On the &c, under Domestication,' vol. i. p.
characters of chickens of different 51. Also vol. ii. p. 71, for a gene-
breeds, and on the breeds of the ral discussion on * Inheritance af
pigeon, alluded to in the following limited by Sex.'
paragraph, see * Variation of Ani-
230 Ttie Descent oj Man. P^kt II
is traiismitted, yet it probably is so, as all shades of colour' aie
strongly inherited by the horse. Nor is this form of inheritance,
as limited by the seasons, more remarkable than its limitation
by age or sex.
Inheritance as Limited by Sex. — The equal transmission of
characters to both sexes is the commonest form of inheritance,
at least with those animals which do not present strongly-marked
sexual differences, and indeed with many of these. But characters
are somewhat commonly transferred exclusively to that sex, in
which they first appear. Ample evidence on this head has been
advanced in my work on ' Variation under Domestication,' but a
few instances may here be given. There are breeds of the sheep
and goat, in which the horns of the male differ greatly in shape
from those of the female ; and these differences, acquired under
domestication, are regularly transmitted to the same sex. As a
rule, it is the females alone in cats which are tortoise-shell,
the corresponding colour in the males being rusty-red. With
most breeds of the fowl, the characters proper to each sex
are transmitted to the same sex alone. So general is this form
of transmission that it is an anomaly when variations in certain
breeds are transmitted equally to both sexes. There are also
certain sub-breeds of the fowl in which the males can hardly be
distinguished from one another, whilst the females differ con-
siderably in colour. The sexes of the pigeon in the parent-species
do not differ in any external character; nevertheless, in certain
domesticated breeds the male is coloured differently from the
female. 36 The wattle in the English Carrier pigeon, and the crop
in the Pouter, are more highly developed in the male than in the
female ; and although these characters have been gained through
long-continued selection by man, the slight differences between
the sexes are wholly due to the form of inheritance which has
prevailed ; for they have arisen, not from, but rather in opposi-
tion to, the wish of the breeder.
Most of our domestic races have been formed by the accumula-
tion of many slight variations ; and as some of the successive
steps have been transmitted to one sex alone, and some to both
sexes, we find in the different breeds of the same species all
gradations between great sexual dissimilarity and complete
similarity. Instances have already been given with the breeds
of the fowl and pigeon, and under nature analogous cases are
36 Dr. Chapuis, * Le Pigeon Voya- . similar differences in certain breeds
geur Beige/ 1865, p. 87. Boitard at Modena, ' Le variazioni dei
et Corbie, ' Les Pigeons de Voliere/ Colombi domestici/ del Paolo Bo-
&c, 1824, p. 173. See, also, on niz*i, 1873.
Chap. YIII. Sexual Selection 231
common. With animals under domestication, but whether in
nature I will not venture to say, one sex may lose characters
proper to it, and may thus come somewhat to resemble tho
opposite sex ; for instance, the males of some breeds of the fowl
have lost their masculine tail-plumes and hackles. On the
other hand, the differences between the sexes may be increased
under domestication, as with merino sheep, in which the
ewes have lost their horns. Again, characters proper to one
sex may suddenly appear in the other sex ; as in those sub-
breeds of the fowl in which the hens acquire spurs whilst young ;
or, as in certain Polish sub-breeds, in which the females, as
there is reason to believe, originally acquired a crest, and sub-
sequently transferred it to the males. All these cases are in-
telligible on the hypothesis of pangenesis ; for they depend on
the gemmules of certain parts, although present in both sexes,
becoming, through the influence of domestication, either dormant
or developed in either sex.
There is one difficult question which it will be convenient to
defer to a future chapter ; namely, whether a character at first
developed in both sexes, could through selection be limited in
its development to one sex alone. If, for instance, a breeder
observed that some of his pigeons (of which the characters are
usually transferred in an equal degree to both sexes) varied into
pale blue, could he by long-continued selection make a breed,
in which the males alone should be of this tint, whilst the females
remained unchanged ? I will here only say, that this, though
perhaps not impossible, would be extremely difficult; for the
natural result of breeding from the pale-blue males would be
to change the whole stock of both sexes to this tint. If, how-
ever, variations of the desired tint appeared, which were . from
the first limited in their development to the male sex, there would
not be the least difficulty in making a breed with the two sexes
of a different colour, as indeed has been effected with a Belgian
breed, in which the males alone are streaked with black. In a
similar manner, if any variation appeared in a female pigeon,
which was from the first sexually limited in its development to
the females, it would be easy to make a breed with the females
alone thus characterised ; but if the variation was not thus
originally limited, the process would be extremely difficult, per-
haps impossible. 37
* 7 Since the publication of the perienced a breeder as Mr. Teget-
first edition of this work, it has meier. After describing some cu-
beeD highly satisfactory to me to rious castjs in pigeons, of the trans-
it the following remarks (the mission of colour by one sex alone,
field/ Sept. 1872) from so ex- and the formation of a sub-fcreeii
232 The Descent of Man, Vwr II
On the Belation between the Period of Development of a Character
and its Transmission to one Sex or to both Sexes. — Why certain
characters should be inherited by both sexes, and other charac-
ters by one sex alone, namely by that sex in which the character
first appeared, is in most cases quite unknown. We cannot even
conjecture why with certain sub-breeds of the pigeon, black
striae, though transmitted through the female, should be deve-
loped in the male alone, whilst every other character is equally
transferred to both sexes. Why, again, with cats, the tortoise-
shell colour should, with rare exceptions, be developed in the
female alone. The very same character, such as deficient or su-
pernumerary digits, colour-blindness, &c, may with mankind bo
inherited by the males alone of one family, and in another family
by the females alone, though in both cases transmitted through
the opposite as well as through the same sex. 38 Although we aro
thus ignorant, the two following rules seem often to hold good —
that variations which first appear in either sex at a late period of
life, tend to be developed in the same sex alone ; whilst variations
which first appear early in life in either sex tend to be developed in
both sexes. I am, however, far from supposing that this is the
sole determining cause. As I have not elsewhere discussed this
subject, and as it has an important bearing on sexual selection,
I must here enter into lengthy and somewhat intricate details.
It is in itself probable that any character appearing at an
early age would tend to be inherited equally by both sexes, for
the sexes do not differ much in constitution before the power
of reproduction is gained. On the other hand, after this power
has been gained and the sexes have come to differ in constitution,
the gemmules (if I may again use the language of pangenesis)
which are cast off from each varying part in the one sex would
be much more likely to possess the proper affinities for uniting
with the tissues of the same sex, and thus becoming developed,
than with those of the opposite sex.
I was first led to infer that a relation of this kind exists, from
the fact that whenever and in whatever manner the adult male
differs from the adult female, he differs in the same manner from
the young of both sexes. The generality of this fact is quite
remarkable: it holds good with almost all mammals, birds,
with this character, he says : " It is " facts that I have related ; but it
" a singular circumstance that Mr. " is remarkable how very closely
" Darwin should have suggested the " he suggested the right method of
" possibility of modifying the sexual " procedure."
" colours of birds by a course of 38 References are given in my
" artificial selection. When he did VariaUon of Animals under Domea-
•• so, he was in ignorant of these tication,' vol. ii. p. 72.
Chap. VIIL Sexual Selection. 233
amphibians, and fishes ; also with many crustaceans, spiders, and
some few insects, such as certain orthoptera and libellulse. In
all these cases the variations, through the accumulation of which
the male acquired his proper masculine characters, must have
occurred at a somewhat late period of life ; otherwise the young
males would have been similarly characterised ; and conformably
with our rule, the variations are transmitted to and developed in
the adult males alone. When, on the other hand, the adult male
closely resembles the young of both sexes (these, with rare
exceptions, being alike), he generally resembles the adult female ;
and in most of these cases the variations through which the young
and old acquired their present characters, probably occurred,
according to our rule, during youth. But there is here room for
doubt, for characters are sometimes transferred to the offspring
at an earlier age than that at which they first appeared in the
parents, so that the parents may have varied when adult, and
have transferred their characters to their offspring whilst young.
There are, moreover, many animals, in which the two sexes closely
resemble each other, and yet both differ from their young ; and
here the characters of the adults must have been acquired late in
life ; nevertheless, these characters, in apparent contradiction to
our rule, are transferred to both sexes. We must not, however,
overlook the possibility or even probability of successive varia-
tions of the same nature occurring, under exposure to similar
conditions, simultaneously in both sexes at a rather late period
of life ; and in this case the variations would be transferred to
the offspring of both sexes at a corresponding late age ; and theru
would then be no real contradiction to the rule that variations
occurring late in life are transferred exclusively to the sex in
which they first appeared. This latter rule seems to hold true
more generally than the second one, namely, that variations
which occur in either sex early in life tend to be transferred to
both sexes. As it was obviously impossible even to estimate in
how large a number of cases throughout the animal kingdom
these two propositions held good, it occurred to me to investigate
some striking or crucial instances, and to rely on the result.
An excellent case for investigation is afforded by the Deer
family. In all the species, but one, the horns are developed
only in the males, though certainly transmitted through the
females, and capable of abnormal development in them. In the
reindeer, on the other hand, the female is provided with horns ;
so that in this species, the horns ought, according to our rule,
to appear early in life, long before the two sexes are mature
and have come to differ much in constitution. In all the
uther species the horns ought to appear later in life, which
234 The Descent of Man. Part IL
would lead to tlieir development in that sex alone, in which
they first appeared in the progenitor of the whole Family. Now
in seven species, belonging to distinct sections of the family and
inhabiting different regions, in which the stags alone bear horns,
I find that the horns first appear at periods, varying from nine
months after birth in the roebuck, to ten, twelve or even more
months in the stags of the six other and larger species. 89 But
with the reindeer the case is widely different ; for, as I hear from
Prof. Nilsson, who kindly made special enquiries for me in
Lapland, the horns appear in the young animals within four or
five weeks after birth, and at the same time in both sexes. So
that here we have a structure, developed at a most unusually
early age in one species of the family, and likewise common to
both sexes in this one species alone.
In several kinds of antelopes, only the males are provided with
horns, whilst in the greater number both sexes bear horns.
With respect to the period of development, Mr. Blyth informs
me that there was at one time in the Zoological Gardens a young
koodoo {Ant. strepsiceros), of which the males alone are horned,
and also the young of a closely-allied species, the eland (Ant.
oreas), in which both sexes are horned. Now it is in strict
conformity with our rule, that in the young male koodoo,
although ten months old, the horns were remarkably small, con-
sidering the size ultimately attained by them; whilst in the
young male eland, although only three months old, the horns
were already very much larger than in the koodoo. It is
also a noticeable fact that in the prong-horned antelope, 40
only a few of the females, about one in five, have horns, and
these are in a rudimentary state, though sometimes above four
inches long; so that as far as concerns the possession of horns
by the males alone, this species is in an intermediate condition,
and the horns do not appear until about five or six months after
birth. Therefore in comparison with what little we know of
the development of the horns in other antelopes, and from what
39 I am much obliged to Mr. tinent, see J. D. Caton, in ' Ottawa
Cwpples for having made enquiries Acad, of Nat. Sc. 1868, p. 13. For
for me in regard to the Roebuck Cervus Eldi of Pegu, see Lieut,
and Red Deer of Scotland from Mr. Beavan, *Proc. Zoolog. Scs.' 1867,
Robertson, the experienced head- p. 762.
forester to the Marquis of Breadal- 40 Antilocapra Americana. I have
bane. In regard to Fallow-deer, I to thank Dr. Canfield for informa-
have to thank Mr. Eyton and tion with respect to the horns of the
others for information. For the female : see also his paper in ' Proc.
Cervus alces of N. America, see Zoolog. Soc/ 1866, p. 1C9. Also
4 Land and Water/ 1868, pp. 221 Owen, * Anatomy of Vertebrates,
and 254 ; and for the C. Virginianus vol. iii. p. 627.
ina strong yloceros of the same coa-
Chap. VIII. Sexual Selection. 235
we do know with respect to the horns of deer, cattle, &a, thoso
of the prong-horned antelope appear at an intermediate period
of life,— that is, not very early, as in cattle and sheep, nor very
late, as in the larger deer and antelopes. The horns of sheep,
goats, and cattle, which are well developed in both sexes, though
not quite equal in size, can be felt, or even seen, at birth or soon
afterwards. 41 Our rule, however, seems to fail in some breeds
of sheep, for instance merinos, in which the rams alone are
horned; for I cannot find on enquiry, 42 that the horns are
developed later in life in this breed than in ordinary sheep in
which both sexes are horned. But with domesticated sheep the
presence or absence of horns is not a firmly fixed character ; for
a certain proportion of the merino ewes bear small horns, and
some of the rams are hornless; and in most breeds hornless
ewes are occasionally produced.
Dr. W. Marshall has lately made a special study of the pro-
tuberances so common on the heads of birds, 43 and he comes
to the following conclusion ; — that with those species in which
they are confined to the males, they are developed late in
life; whereas with those species in which they are common to
the two sexes, they are developed at a very early period. This is
certainly a striking confirmation of my two laws of inheritance.
In most of the species of the splendid family of the Pheasants,
the males differ conspicuously from the females, and they acquire
their ornaments at a rather late period of life. The eared
pheasant (Crossoptilon auriturn), however, offers a remarkable
exception, for both sexes possess the fine caudal plumes, the
large ear-tufts and the crimson velvet about the head ; I find
that all these characters appear very early in life in accordance
with rule. The adult male can, however, be distinguished from
the adult female by the presence of spurs; and conformably
41 1 have been assured that the however, a breed of sheep in which,
horns of the sheep in North Wales as with merinos, the rams alone
can always be felt, and are some- bear horns ; and Mr. Win wood
times even an inch in length, at Reade informs me that in one cast)
birth. Youatt says (' Cattle,' 1834, observed by him, a young ram,
p. 277), that the prominence of born on Feb. 10th, first shewed
the frontal bone in cattle penetrates horns on March 6th, so that in this
the cutis at birth, and that the instance, in conformity with rule,
horny matter is soon formed over the development of the horns oc-
it. curred at a later period of life than
42 I am greatly indebted to Prof, in Welsh sheep, in which both sexes
Victor Caru3 for having made en- are horned.
quiiies for me, from the highest 43 * Ueber die knochernen Schiidel-
authorities, with respect to the hooker der Vogel' in the * Nieder-
merino sheep of Saxony. On the landiscnen Archiv fur Zoologie,'
Quiaea coast of Africa there is, Band I. Heft 2, 1872.
236 The Descent of Man. Pab$ II
with our rule, these do not begin to be developed before the age
of six months, as I am assured by Mr. Bartlett, and even at this
age, the two sexes can hardly be distinguished. 44 The male and
female Peacock differ conspicuously from each other in almost
every part of their plumage, except in the elegant head-crest,
which is common to both sexes ; and this is developed very early
in life, long before the other ornaments, which are confined to the
male. The wild-duck offers an analogous case, for the beautiful
green speculum on the wings is common to both sexes, though
duller and somewhat smaller in the female, and it is developed
early in life, whilst the curled tail-feathers and other ornaments
of the male are developed later. 46 Between such extreme cases
of close sexual resemblance and wide dissimilarity, as those of
the Crossoptilon and peacock, many intermediate ones could be
given, in which the characters follow our two rules in their order
of development.
As most insects emerge from the pupal state in a mature
condition, it is doubtful whether the period of development can
determine the transference of their characters to one or to both
sexes. But we do not know that the coloured scales, for instance,
in two species of butterflies, in one of which the sexes differ in
colour, whilst in the other they are alike, are developed at the
same relative age in the cocoon. Nor do we know whether all
the scales are simultaneously developed on the wings of the same
species of butterfly, in which certain coloured marks are confined
44 In the common peacock (Pavo sexes; but I have not been able to
cristatus) the male alone possesses discover whether its full develop-
spurs, whilst both sexes of the Java ment occurs later in life in the
Peacock (P. muticus) offer the un- males of such species, than in the
usual case of being furnished with male of the common duck, as ought
spurs. Hence I fully expected that to be the case according to our
in the latter species they would rule. With the allied Mergus cu~
have been developed earlier in life cullatus we have, however, a case of
than in the common peacock; but this kind: the two sexes differ con-
M. Hegt of Amsterdam informs me, spicuously in general plumage, and
that with young birds of the pre- to a considerable degree in the
vious year, of both species, com- speculum, which is pure white in
pared on April 23rd, .1869, there the male and greyish-white in the
was no difference in the develop- female. Now the young males at
ment of the spurs. The spurs, first entirely resemble the females,
however, were as yet represented and have a greyish-white speculum,
merely by slight knobs or eleva- which becomes pure white at an
tions. I presume that I should earlier age than that at which the
have been informed if any difference adult male acquires his other and
in the rate of development had more strongly-marked sexual dil-
been observed subsequently. ferences : see Audubon, 'Ornltfeo
45 In some other species of the logical Biography/ vol. iii. 1L*35,
Duck family the speculum differs pp. 249 250.
: -n a greater degree in the two
Chap. VIII. Sexual Selection. 237
to one sex. whilst others are common to both sexes. A difference
of this kind in the period of development is not so improbable as
it may at first appear ; for with the Orthoptera, which assume
their adult state, not by a single metamorphosis, but by a suc-
cession of moults, the young males of some species at first
resemble the females, and acquire their distinctive masculine
characters only at a later moult. Strictly analogous cases occur
at the successive moults of certain male crustaceans.
We have as yet considered the transference of characters, re-
latively to their period of development, only in species in a
natural state; we will now turn to domesticated animals, and
first touch on monstrosities and diseases. The presence of super-
numerary digits, and the absence of certain phalanges, must be
determined at an early embryonic period — the tendency to profuse
bleeding is at least congenital, as is probably colour-blindness-
yet these peculiarities, and other similar ones, are often limited
in their transmission to one sex; so that the rule that
characters, developed at an early period, tend to be trans-
mitted to both sexes, here wholly fails. But this rule as
before remarked, does" not appear to be nearly so general as the
converse one, namely, that characters which appear late in life
in one sex are transmitted exclusively to the same sex. From
the fact of the above abnormal peculiarities becoming attached
to one sex, long before the sexual functions are active, we may
infer that there must be some difference between the sexes at an
extremely early age. With respect to sexually-limited diseases,
we know too little of the period at which they originate, to draw
any safe conclusion. Gout, however, seems to fall under our
rule, for it is generally caused by intemperance during manhood,
and is transmitted from the father to his sons in a much more
marked manner than to his daughters.
In the various domestic breeds of sheep, goats, and cattle, the
males differ from their respective females in the shape or develop-
ment of their horns, forehead, mane, dewlap, tail, and hump on
the shoulders ; and these peculiarities, in accordance with our
rule, are not fully developed until a rather late period of life.
The sexes of dogs do not differ, except that in certain breeds,
especially in the Scotch deer-hound, the male is much larger
and heavier than the female ; and, as we shall see in a future
chapter, the male goes on increasing in size to an unusually late
period of life, which, according to rule, will account for his in-
creased size being transmitted to his male offspring alone. On
the other hand, the tortoise-shell colour, which is confined to
female cats, is quite distinct at birth, and this case violates the
rule. There is a breed of pigeons in which the males alone ar3
2$8 The Descent of Man. Part II
streaked with black, and the streaks can be detected even in the
nestlings ; but they become more conspicuous at each successive
moult, so that this case partly opposes and partly supports the
rule. With the English Carrier and Pouter pigeons, the full
development of the wattle and the crop occurs rather late in life,
and conformably with the rule, these characters are transmitted
in full perfection to the males alone. The following cases perhaps
come within the class previously alluded to, in which both sexes
have varied in the same manner at a rather late period of life,
and have consequently transferred their new characters to both
sexes at a corresponding late period ; and if so, these cases are
not opposed to our rule : — there exist sub-breeds of the pigeon,
described by Neumeister, 46 in which both sexes change their
colour during two or three moults (as is likewise the case with
the Almond Tumbler), nevertheless, these changes, though
occurring rather late in life, are common to both sexes. One
variety of the Canary-bird, namely the London Prize, offers a
nearly analogous case.
With the breeds of the Fowl the inheritance of various charac-
ters by one or both sexes, seems generally determined by the
period at which such characters are developed. Thus in all the
many breeds in which the adult male differs greatly in colour
from the female, as well -as from the wild parent-species, he
differs also from the young male, so that the newly-acquired
characters must have appeared at a rather late period of life.
On the other hand, in most of the breeds in which the two sexes
resemble each other, the young are coloured in nearly the same
manner as their parents, and this renders it probable that their
colours first appeared early in life. We have instances of this
fact in all black and white breeds, in which the young and old
of both sexes are alike ; nor can it be maintained that there is
something peculiar in a black or whito plumage, which leads to
its transference to both sexes; for the males alone of many
natural species are either black or white, the females being
differently coloured. With the so-called Cuckoo sub-breeds of
the fowl, in which the feathers are transversely pencilled with
dark stripes, both sexes and the chickens are coloured in nearly
the same manner. The laced plumage of the Sebright bantam
is the same in both sexes, and in the young chickens the wing-
feathers are distinctly, though imperfectly laced. Spangled
Ham burgs, however, offer a partial exception ; for the two sexes,
though not quite alike, resemble each other more closely than
46 * Das Ganze der Taubenzucht,' puis, ' Le pigeon voyageur Beige,'
1837, s. 21, 24. For the case of 1865, p. 87.
the streaked pigeons, see Or Cha-
Chap. VIII. Sexual Selection, 239
do the sexes of the aboriginal parent-species ; yet they acquire
their characteristic plumage late in life, for the chickens are
distinctly pencilled. With respect to other characters besides
colour, in the wild-parent species and in most of the domestic
breeds, the males alone possess a well-developed comb ; but in
the young of the Spanish fowl it is largely developed at a very
early age, and, in accordance with this early development in the
male, it is of unusual size in the adult female. In the Game
breeds pugnacity is developed at a wonderfully early age, of
which curious proofs could be given ; and this character is trans-
mitted to both sexes, so that the hens, from their extreme
pugnacity, are now generally exhibited in separate pens. With
the Polish breeds the bony protuberance of the skull which
supports the crest is partially developed even before the chickens
are hatched, and the crest itself soon begins to grow, though at
first feebly; 47 and in this breed the adults of both sexes are
characterised by a great bony protuberance and an immense crest.
Finally, from what we have now seen of the relation which
exists in many natural species and domesticated races, between
the period of the development of their characters and the
manner of their transmission — for example, the striking fact of
the early growth of the horns in the reindeer, in which both
sexes bear horns, in comparison with their much later growth
in the other species in which the male alone bears horns — we
may conclude that one, though not the sole cause of characters
being exclusively inherited by one sex, is their development at
a late age. And secondly, that one, though apparently a less
efficient cause of characters being inherited by both sexes, is
their development at an early age, whilst the sexes differ
but little in constitution. It appears, however, that some
difference must exist between the sexes even during a very
early embryonic period, for characters developed at this age not
rarely become attached to one sex.
Summary and concluding remarks. — From the foregoing dis-
cussion on the various laws of inheritance, we learn that the
characters of the parents often, or even generally, tend to become
developed in the offspring of the same sex, at the same age, and
periodically at the same season of the! year, in which they first
47 For full particulars and re- 250, 256. In regard to the higher
ferences on all these points respect- animals, the sexual differences which
m* the several Weeds of the Fowl, have arisen under domestication are
see * Variation of Animals and Plants described in the same work under
mider Domestication, vol. i. pp. the head of each species.
240 The Descent of Man Part II
appeared in the parents. But these rules,, owing to unknown
causes, are far from being fixed. Hence during the modification
of a species, the successive changes may readily be transmitted
in different ways ; some to one sex, and some to both ; some to
the offspring at one age, and some to the offspring at all ages.
Not only are the laws of inheritance extremely complex, but so
are the causes which induce and govern variability. The
variations thus induced are preserved and accumulated by
sexual selection, which is in itself an extremely complex affair,
depending, as it does, on the ardour in love, the courage, and
the rivalry of the males, as well as on the powers of perception,
the taste, and will of the female. Sexual selection will also
be largely dominated b.y natural selection tending towards
the general welfare of the species. Hence the manner in which
the individuals of either or both sexes have been affected
through sexual selection cannot fail to be complex in the highest
degree.
"When variations occur late in life in one sex, and are trans-
mitted to the same sex at the same age, the other sex and the
young are left unmddified. When they occur late in life, but
are transmitted to both sexes at the same age, the young alone
are left unmodified. Variations, however, may occur at any
period of life in one sex or in both, and be transmitted to both
sexes at all ages, and then all the individuals of the species
are similarly modified. In the following chapters it will be seen
that all these cases frequently occur in nature.
Sexual selection can never act on any animal before the age
for reproduction arrives. From the great eagerness of the male
it has generally acted on this sex and not on the females. The
males have thus become provided with weapons for fighting
with their rivals, with organs for discovering and securely
holding the female, and for exciting or charming her. When
the sexes differ in these respects, it is also, as we have seen, an
extremely general law that the adult male differs more or less
from the young male ; and we may conclude from this fact that
the successive variations, by which the adult male became modi-
fied, did not generally occur much before the age for reproduction.
Whenever some or many of the variations occurred early in
life, the young males would partake more or less of the charac-
ters of the adult males ; and differences of this kind between
the old and young males may be observed in many species of
animals.
It is probable that young male animals have often tended to
vary in a manner which would not only have been of no use to
them at an early age, but would have been actually injurious—
Giap. VI iL Sexual Selection* 241
as by acquiring bright colours, which would render them con-
spicuous to their enemies, or by acquiring structures, such as
goat horns; which would expend much vital force in their
development. Variations of this kind occurring in the young
males would almost certainly be eliminated through natural
selection. With the adult and experienced males, on the other
hand* the advantages derived from the acquisition of such
characters, would more than counterbalance some exposure to
danger, and some loss of vital force.
As variations which give to the male a better chance of
conquering other males, or of finding, securing, or charming the
opposite sex, would, if they happened to arise in the female, be
of no service to her, they would not be preserved in her through
sexual selection. We have also good evidence with domesticated
animals, that variations of all kinds are, if not carefully selected,
soon lost through intercrossing and accidental deaths. Conse-
quently in a state of nature, if variations of the above kind chanced
to arise in the female line, and to be transmitted exclusively in
this line, they would be extremely liable to be lost. If, however,
the females varied and transmitted their newly acquired
characters to their offspring of both sexes, the characters which
were advantageous to the males would be preserved by them
through sexual selection, and the two sexes would in consequence
be modified in the same manner, although such characters were of
no use to the females ; but I shall hereafter have to recur to these
more intricate contingencies. Lastly, the females may acquire, and
apparently have often acquired by transference, characters from
the male sex.
As variations occurring late in life, and transmitted to one
sex alone, have incessantly been taken advantage of and accumu-
lated through sexual selection in relation to the reproduction of
the species ; therefore it appears, at first sight, an unaccountable
fact that similar variations have not frequently been accumu-
lated through natural selection, in relation to the ordinary
habits of life. If this had occurred, the two sexes would often
have been differently modified, for the sake, for instance, of
capturing prey or of escaping from danger. Differences of this
kind between the two sexes do occasionally occur, especially in
the lower classes. But this implies that the two sexes follow
different habits in their struggles for existence, which is a rare
circumstance with the higher animals. The case, however, is
widely different with the reproductive functions, in which respect
the sexes necessarily differ. For variations in structure which
are related to these functions, have often proved of value to one
sex and from having arisen at a late period of life, have been
242 The Descent of Man. Pas? 11
transmitted to one sex alone ; and such variations, thus preserved
and transmitted, have given rise to secondary sexual characters.
In the following chapters, I shall treat of the secondary
sexual characters in animals of all classes, and shall endeavour in
each case to apply the principles explained in the present
chapter. The lowest classes will detain us for a very short time,
but the higher animals, especially birds, must be treated at
considerable length. It should be borne in mind that for
reasons already assigned, I intend to give only a few illustrative
instances of the innumerable structures by the aid of which the
male finds the female, or, when found, holds her. On the other
hand, all structures and instincts by the aid of which the male
conquers other males, and by which he allures or excites the
female, will be fully discussed, as these are in many ways the
most interesting.
Supplement on the proportional numbers of the two sexes in animals
belonging to various classes.
As no one, as far as I can discover, has paid attention to the
relative numbers of the two sexes throughout the animal
kingdom, I will here give such materials as I have been able to
collect, although they are extremely imperfect. They consist in
only a few instances of actual enumeration, and the numbers are
not very large. As the proportions are known with certainty only
in mankind, I will first give them as a standard of comparison.
Man.— In England during ten years (from 1857 to 1866) the
average number of children born alive yearly was 707,120, in
the proportion of 104*5 males to 100 females. But in 1857 the
male births throughout England were as 105*2, and in 1865 as
104*0 to 100. Looking to separate districts, in Buckingham-
shire (where about 5000 children are annually born) the mean
proportion of male to female births, during the whole period of
the above ten years, was as 102*8 to 100; whilst in N. Wales
(where the average annual births are 12,873) it was as high
as 106-2 to 100. Taking a still smaller district, viz., But-
landshire (where the annual births average only 739), in 1864
the male births were as 114*6, and in 1862 as only 97*0 to
100; but even in this small district the average of the 7385
births during the whole ten years, was as 104*5 to 100 ; that is in
the same ratio as throughout England. 48 The proportions are
sometimes slightly disturbed by unknown causes; thus Prof.
48 * Twenty-ninth Annual Report In this report (p. xii.) a special d€>
•f the Kagistrar-General for 1866.* cennial table is given.
CstA*. VtiL Proportion of the Sexes. 24$
Faye states " that iD some districts of Norway there has been
" during a decennial period a steady deficiency of boys, whilst
c ' in others the opposite condition has existed." In France
during forty-four years the male to the female births have been
as 106*2 to 100; but during this period it has occurred five
times in one department, and six times in another, that the
female births have exceeded the males. In Eussia the average
proportion is as high as 108*9, and in Philadelphia in the United
States as 110*5 to 100. 49 The average ibr Europe, deduced by
Bickes from about seventy million births, is 106 males to 100
females. On the other hand, with white^ children born at the
Cape of Good Hope, the proportion of males is so low as to fluctuate
during successive years between 90 and 99 males for every 100
females. It is a singular fact that with Jews the proportion of
male births is decidedly larger than with Christians : thus in
Prussia the proportion is as 113, in Breslau as 114, and in
Livonia as 120 to 100; the Christian births in these countries
being the same as usual, for instance, in Livonia as 104 to 100. 59
Prof. Faye remarks that " a still greater preponderance of
" males would be met with, if death struck both sexes in equal
" proportion in the womb and during birth. But the fact is, that
" for every 100 still-torn females, we have in several countries
" from 134*6 to 144*9 still-born males. During the first four or
" five years of life, alrco, more male children die than females ;
" for example in England, during the first year, 126 boys die for
" every 100 girls— a proportion which in France is still more
" unfavourable." 51 Dr. Stockton-Hough accounts for these facts
in part by the more frequent defective development of males
than of females. "We have before seen that the male sex is more
49 For Norway and Russia, see 343. Dr. Stark also remarks
abstract of Prof. Faye's researches, (' Tenth Annual Report of Births,
in • British and Foreign Medico- Deaths. &c, in Scotland/ 1867, p.
Chirurg. Review/ April, 1867, pp. xxviii.) that "These examples may
343, 345. For France, the ' An- " suffice to shew that, at almost
nuaire pour l'An 1867/ p. 213. " every stage of life, the males in
For Philadelphia, Dr. Stockton- " Scotland have a greater liability
Hough, * Social Science Assoc.' 1874. " to death and a higher death-rate
For the Cape of Good Hope, Quetelet " than the females. The fact, how-
as quoted by Dr. H. H. Zouteveen, "ever, of this peculiarity being
in the Dutch Translation of this " most strongly developed at that
work (vol. i. p. 417), where much " infantile period of life when the
information is given on the propor- " dress, food, and general treatment
tion of the sexes. " of both sexes are alike, seems tc
60 In regard to the Jews, see M. " prove that the higher male death-
Thurv, * La Loi de Production des " rate is an impressed, natural, and
Sexes/ 1863, p. 25. " constitutional peculiarity due tc
11 * British and Foreign Medico- " sex alone."
Qururg. Review/ April, 1867, p.
B 2
244 The Descent of Man. Pae* li
variable in structure than the female; and variations in im-
portant organs would generally be injurious. But the size of
the body, and especially of the head, being greater in male than
iemale infants is another cause; for the males are thus more
liable to be injured during parturition. Consequently the still-
born males are more numerous; and, as a highly competent judge,
Dr. Crichton Browne, 62 believes, male infants often suffer in health
for some years after birth. Owing to this excess in the death-
rate of male children, both at birth and for some time sub-
sequently, and owing to the exposure of grown men to various
dangers, and to their tendency to emigrate, the females in all
old-settled countries, where statistical records have been kept, 63
are found to preponderate considerably over the males.
It seems at first sight a mysterious fact that in different
nations, under different conditions and climates, in Naples,
Prussia, Westphalia, Holland, France, England and the United
States, the excess of .male over female births is less when they
are illegitimate than when legitimate. 54 This has been explained by
different writers in many different ways, as from the mothers
being generally young, from the large proportion of, first preg-
nancies, &c. But wo have seen that male infants, from the large
size of their heads, suffer more than female infants during
parturition ; and as the mothers of illegitimate children must be
more liable than other women to undergo bad labours, from
various causes, such as attempts at concealment by tight lacing,
hard work, distress of mind, &c, their male infants would
proportionably suffer. And this probably is the most efficient
of all the causes of the proportion of males to females born
alive being less amongst illegitimate children than amongst the
legitimate. With most animals the greater size of the adult
male than of the female, is due to the stronger males having
conquered the weaker in their straggles for the possession of
the females, and no doubt it is owing to this fact that the two
sexes of at least some animals differ in size at birth. Thus
58 ' West Kiding Lunatic Asylum Paraguay, according to the accurate
Reports,' vol. i. 1871, p. 8. Sir J. Azara ( 4 Voyages dans I'Amerique
Simpson has proved that the head merid.' torn. ii. 1809, p. 60, 179),
of the male infant exceeds that of the women are to the men in the
the female by 3-8ths of an inch in proportion of 14 to 13.
circumference, and by l-8th in 54 Babbage, * Edinburgh Journal
transverse diameter. Quetelet has of Science,' 1829, vol. i. p. 88 ; also
ihewn that woman is born smaller p. 90, on still-born children. Oa
than man; see Dr. Duncan, 'Fe- illegitimate children in England,
cundity, Fertility, Sterility,* 1871, see 'Report of Registrar-General
p. 382. for 1866/ p. xv,
** With the savage Guaranys of
Chap. VIII. Proportion of the Sexes. 245
we have the curious fact that we may attribute the more
frequent deaths of male than female infants, especially amongst
the illegitimate, at least in part to sexual selection.
It has often been supposed that the relative age of the two
parents determines the sex of the offspring ; and Prof. Leuckart 05
has advanced what he considers sufficient evidence, with respect
to man and certain domesticated animals, that this is one impor-
tant though not the sole factor in the result. So again the period
of impregnation relatively to the state of the female has been,
thought by some to be the efficient cause ; but recent observa-
tions discountenance this belief. According to Dr. Stockton-
Hough, 66 the season of the year, the poverty or wealth of the
parents, residence in the country or o cities, the crossing of
foreign immigrants, &c, all influence the proportion of the
sexes. With mankind, polygamy has also been supposed to lead
to the birth of a greater proportion of female infants ; but Dr. J.
Campbell 67 carefully attended to this subject in the harems of
Siam, and concludes that the proportion of male to female births
is the same as from monogamous unions. Hardly any animal
has been rendered so highly polygamous as the English race-
horse, and we shall immediately see that his male and female
oflspring are almost exactly equal in number. I will now give
the facts which I have collected with respect to the proportional
numbers of the sexes of various animals ; and will then briefly
discuss how far selection has come into play in determining the
result.
Horses. — Mr. Tegetmeier has been so kind as to tabulate for me from
the 'Racing Calendar' the births of race-horses daring a period of
twenty-one years, viz., from 1846 to 1867 ; 1849 being omitted, as no
returns were that year published. The total births were 25,560, 58 con-
sisting of 12,763 male3 and 12,797 females, or in the proportion of 99*7
males to 100 females. As these numbers are tolerably large, and as
they are drawn from all parts of England, during several years, we may
with much confidence conclude that with the domestic horse, or at
least with the race-horse, the two sexes are produced in almost equal
numbers. The fluctuations in the proportions during successive years
55 Leuckart (in Wagner 'Hand- notice, as shewing how infertile
worterbuch der Phys.' L. iv, 1853, these highly-nurtured and rathex
s. 774. oiosely-interbred animals have be-
86 Social Science Assoc, of Phila- come, that not far from one-third o!
delphia, 1874. ^ the Diazes failed iD produce lmng
" * Anthropological Rcriew/ foals. Thus during 1866, 809 male
April, 1870, p. cviii. * colts nad 816 female colts were bom,
58 During eleven years a record and 743 mares failed to produce
was kept of the number of mares offspring. During 1867, 836 male*
which proved barren or prematurely and 902 females were born, ap4 7#4
slipped their foals ; and it observes mares failed,
246 The Descent of Man, Fabs IL
are closely like those which occur with mankind, when a small and
thinly -populated area is considered ; thus in 1856 the male horses were
as 107*1, and in 1867 as only 92'6 to 100 females. In the tabulated
returns the proportions vary in cycles, for the males exceeded tho
females during six successive years; and the females exceeded the
males during two periods each of four years : this, however, may be
accidental ; at least I can detect nothing of the kind with man in the
decennial table in the Registrar's Report for 1866.
Dogs. — During a period of twelve years, from 1857 to 1868, the births
of a large number of greyhounds, throughout England, were sent to
the * Field' newspaper ; and I am again indebted to Mr. Tegetmeier for
carefully tabulating tho results. The recorded births were 6878,
consisting of 3605 males and 3273 females, that is, in the proportion of
110*1 males to 100 females. The greatest fluctuations occurred in
1864, when the proportion was as 95*3 males, and in 1867, as 116-3
males to 100 females. The above average proportion of 110*1 to 100 is
probably nearly correct in the case of the greyhound, but whether it
would hold with other domesticated breeds is in some degree doubtful.
Mr. Cupples has enquired from several great breeders of dogs, and finds
that all without exception believe that females are produced in excess ;
but he suggests that this belief may have arisen from females being
less valued, and from the consequent disappointment producing a
stronger impression on the mind.
Sheep. — The sexes of sheep are not ascertained by agriculturists until
several months after birth, at the period when the males are castrated ;
so that the following returns do not give the proportions at birth.
Moreover, I find that several great breeders in Scotland, who annually
raise some thousand sheep, are firmly convinced that a larger proportion
of males than of females die during the first year or two. Therefore the
proportion of males would be somewhat larger at birth than at the age of
castration. This is a remarkable coincidence with what, as we have
seen, occurs with mankind, and both cases probably depend on the
same cause. I have received returns from four gentlemen in England
ffho have bred Lowland sheep, chiefly Leicesters, during the last ten to
sixteen years; they amount altogether to 8965 births, consisting of
4407 males and 4558 females; that is in the proportion of 96 7 males to
100 females. With respect to Cheviot and black-faced sheep bred in
Scotland, I have received returns from six breeders, two of them on a
>arge scale, chiefly for the years 1867-1869, but some of the returns
extend back to 1862. The total number recorded amounts to 50,685,
consisting of 25,071 males and 25,614 females, or in the proportion of
97.9 males to 100 females. If we take the English and Scotch returns
together, the total number amounts to 59,650, consisting of 29,478
males and 30,172 females, or as 97*7 to 100. So that with sheep at the
age of castration the females are certainly in excess of the males, but
probably this would not hold good at birth. 59
Of Cattle I have received returns from nine gentlemen of 982 births,
too few to be trusted ; these consisted of 477 bull-calves and 505 cow-
*• I am much indebted to Mr. tion to the premature deaths of the
Cnpples for having procured for me males, — a statement subsequently
the above returns from Scotland, as confirmed by Mr. Aitchison and
well as some of the following re- others. To this latter gentleman,
turns on cattle. Mr. R. Elliot, of and to Mr. Payan, I owe my thank*
Laighwood, first called my atteu- for Urge returns as to sheep.
Chap. VIII. Proportion of the Sexes. 247
calves ; i.e., in the proportion of 94*4 males to 100 females. The Rev.
W. D. Fox informs me that in 1867 out of 34 calves born on a farm in
Derbyshire only one was a bull. Mr. Harrison Weir has enquired from
several breeders of Pigs, and most of them estimate the male to the
female births as about 7 to 6. This same gentleman has bred Rabbit*
for many years, and has noticed that a far greater number of bucks are
produced than does. But estimations are of little value.
Of mammalia in a state of nature I have been able to learn very
little. In regard to the common rat, I have received conflicting
statements. Mr. R. Elliot, of Laighwood, informs me that a rat-catcher
assured him that he had always found the males in great excess, even
with the young in the nest. In consequence of this, Mr. Elliot
himself subsequently examined some hundred old ones, and found the
statement true. Mr. F. Buckland has bred a large number of white
rats, and he also believes that the males greatly exceed the females.
In regard to Moles, it is said that " the males are much more numerous
44 than the females ;" 60 and as the catching of these animals is a special
occupation, the statement may perhaps be trusted. Sir A. Smith, in
describing an antelope of S. Africa 61 (Kobus ellipsiprymnus), remarks,
that in the herds of this and other species, the males are few in number
compared with the females : the natives believe that they are born in
this proportion; others believe that the younger males are expelled
from the herds, and Sir A. Smith says, that though he has himself
never seen herds consisting of young males alone, others affirm that
this does occur. It appears probable that the young when expelled
from the herd, would often fall a prey to the many beasts of prey of the
country.
BIRDS.
With respect to the Fowl, I have received only one account, namely,
that out of 1001 chickens of a highly-bred stock of Cochins, reared
during eight years by Mr. Stretch, 487 proved males and 514 females;
i.e., as 94*7 to 100. In regard to domestic pigeons there is good
evidence either that the males are produced in excess, or that they live
longer ; for these birds invariably pair, and single males, as Mr. Teget-
meier informs me, can always be purchased cheaper than females.
Usually the two birds reared from the two eggs laid in the same nest
are a male and a female ; but Mr. Harrison Weir, who has been so large
a breeder, says that he has often bred two cocks from the same nest,
and seldom two hens ; moreover, the hen is generally the weaker of the
two, and more liable to perish.
With respect to birds in a state of nature, Mr. Gould and others 67
are convinced that the male.* are generally the more numerous; and
as the young males of many species resemble the females, the latter
would naturally appear to be the more numerous. Large numbers of
pheasants are reared by Mr. Baker of Leadenhall from eggs laid by wild
birds, and he informs Mr. Jenner Weir that four or five males to one
female are generally produced. An experienced observer remarks. 63
69 Bell, ' History of British Quad- iv. s. 990) comes to the same con-
rupeds/ p. 100. elusion.
91 ' Illustrations of the Zoology 63 On the authority of L. Lloyd,
of S. Africa,' 1849, pi. 29. 'Game Birds of Sweden/ 1867 pp.
«* Brehm (' Illiist. Thierleben/ B. 12, 132.
248 The Desce?it of Man. Part II,
that in Scandinavia the broods of the capercailzie and black-cock
contain more males than females ; and that with the Dal-ripa (a kind
of ptarmigan) more males than females attend the leks or places of
courtship : bnt this latter circumstance is accounted for by some
observers by a greater number of hen birds being killed by vermin.
From various facts given by White of Selborne, 64 it seems clear that
the males of the partridge must be in considerable excess in the south
of England ; and I have been assured that this is the case in Scotland.
Mr. Weir on enquiring from the dealers, who receive at certain seasons
large numbers of ruffs (Machetes pugnax), was told that the males are
much the more numerous. This same naturalist has also enquired for
me from the birdcatchers, who annually catch an astonishing numbei
of various small species alive for the London market, and he was un-
hesitatingly answered by an old and trustworthy man, that with the
chaffinch the males are in large excess; he thought as high as 2 males to
1 female, or at least as high as 5 to 3. 6a The males of the blackbird.
he likewise maintained, were by far the more numerous, whether
caught by traps or by netting at night. These statements may
apparently be trusted, because this same man said that the sexes are
about equal with the lark, the twite (Linaria montana), and goldfinch.
On the other hand, he is certain that with the common linnet, the
females preponderate greatly, bnt unequally during different years •
during some years he has found the females to the males as four to one.
It should, however, be borne in mind, that the chief season for catching
birds does not begin till September, so that with some species partial
migrations may have begun, and the flocks at this period often consist
of hens alone. Mr. Salvin paid particular attention to the sexes of the
humming-birds in Central America, and he is convinced that with
most of the species the males are in excess ; thus one year he procured
204 specimens belonging to ten species, and these consisted of 166
males and of only 38 females. With two other species the females were
in excess : but the proportions apparently vary either during different
seasons or in different localities; for on one occasion the males of
Campylopterus hemileucurus were to the females as 5 to 2, and on
another occasion 66 in exactly the reversed ratio. As bearing on this
latter point, I may add, that Mr. Powys found in Corfu and Epirus
the sexes of the chaffinch keeping apart, and " the females by far the
" most numerous ;" whilst in Palestine Mr. TriBtram found " the male
" flocks appearing greatly to exceed the female in number." 67 So
again with the Quiscalus major, Mr. G. Taylor 68 says, that in Florida
there were " very few females in proportion to the males," whilst in
Honduras the proportion was the other way, the species there having
the character of a polygamist.
M * Nat. Hist, of Selborne,' letter ever caught by one man in a single
xxix. edit, of 1825, vol. i. p. 139. day was 70.
65 Mr. Jenner Weir received 66 * Ibis,' vol. ii. p. 260, as quoted
similar information, on making en- m Gould's * Trochilidse,' 1861, p.
quiries during the following year. 52. For the foregoing proportions,
To shew the number of living chaf- I am indebted to Mr. Salvin for a
finches caught, I may mention that table of his results.
in 1869 there was a match between 67 'Ibis,' 1860, p. 137; and 1867
two experts, and one man caught p. 369.
in a day 62. and another 40, male 6S 'Ibis/ 1862, p. 137.
chaffinches. The greatest number
Csjap. VIII. Proportion of the Sexes. 249
FISH.
With Fish the proportional numbers of the sexes can be ascertained
only by catching them in the adult or nearly adult state ; and there
are many difficulties in arriving at any just conclusion. 69 Infertile
females might readily be mistaken for males, as Dr. Giinther has
remarked to me in regard to trout. With some species the males are
believed to die soon after fertilising the ova. With many species the
males are of much smaller size than the females, so that a large
number of males would escape from the same net by which the females
were caught. M. Carbonnier, 70 who has especially attended to the
natural history of the pike (Esox lucius), states that many males, owing
to their small size, are devoured by the larger females ; and he believes
that the males of almost all fish are exposed from this same cause to
greater danger than the females. Nevertheless, in tiie few cases in
which the proportional numbers have been actually observed, the
males appear to be largely in excess. Thus Mr. K. Buist, the superin-
tendent of the Stormontfield experiments, says that in 1865, out of 70
salmon first landed for the purpose of obtaining the ova, upwards of 60
were males. In 1867 he again " calls attention to the vast disproportion
" of the males to the females. We had at the outset at least ten males
" to one female." Afterwards females sufficient for obtaining ova were
procured. He adds, " from the great proportion of the males, they aro
"constantly fighting and tearing each other on the spawning-beds." 71
This disproportion, no doubt, ean be accounted for in part, but whether
wholly is doubtful, by the males ascending the rivers before the
females. Mr. F. Buckland remarks in regard to trout, that "it is a
" curious fact that the males preponderate very largely in number over
•* the females. It invariably happens that when the first rush of fish is
" made to the net, there will be at least seven or eight males to one
" female found captive. I cannot quite account for this ; either the
" males are more numerous than the females, or the latter seek safety
" by concealment rather than flight." He then adds, that by carefully
searching the banks sufficient females for obtaining ova can be found. 7 *
Mr. H. Lee informs me that out of 212 trout, taken for this purpose in
Lord Portsmouth's park, 150 were males and 62 females.
The males of the CyprinidsB likewise seem to be in excess ; but
several members of this Family, viz., the carp, tench, bream and
minnow, appear regularly to follow the practice, rare in the animal
kingdom, of polyandry; far the female whilst spawning is always
attended by two males, one on each side, and in the case of the bream
by three or four males. This fact is so well known, that it is always
recommended to stock a pond with two male tenches to one female, or
at least with three males to two females. With the minnow, an
excellent observer states, that on the spawning-beds the males are ten
times as numerous as the females; when a female comes amongst the
49 Leuckart quotes Bloch (Wag- 18, 1869, p. 369.
aer, < Handworterbuch der Phys.' • 1 * The Stormontfield Piscicnl-
B. iv. 1853, s. 775), that with fish tural Experiments/ 1866, p. 23,
there are twice as many males as The * Field ' newspaper, June 29tn,
1867.
10 Quoted in the 'Farmer,' March n « Land and Water/ 1868, p. 41
250 The Descent of Man. Part TL
males, i{ she is immediately pressed closely by a male on each side •
"and when they have been in that situation for a time, are superseded
" by other two males." n
INSECTS.
In this great Class, the Lepidoptera almost alone afford means for
judging of the proportional numbers of the sexes ; for they have been
collected with special care by many good observers, and have been
largely bred from the egg or caterpillar state. I had hoped that some
breeders of silk-moths might have kept an exact record, but after
writing to France and Italy, and consulting various treatises, I cannot
lind that this has ever been done. The general opinion appears to be
that the sexes are nearly equal, but in Italy, as I hear from Professor
Canestrini, many breeders are convinced that the females are produced
in excess. This same naturalist, however, informs me, that in the two
yearly broods of the Ailanthus silk-moth (Bombyx cynfhia), the males
greatly preponderate in the first, whilst in the second the two sexes are
nearly equal, or the females rather in excess.
In regard to Butterflies in a state of nature, several observers have
been much struck by the apparently enormous preponderance of the
males. 74 Thus Mr. Bates, 75 in speaking of several species, about a
hundred in number, which inhabit the Upper Amazons, says that the
males are much more numerous than the females, even in the propor-
tion of a hundred to one. In North America, Edwards, who had great
experience, estimates in the genus Papilio the males to the females as
four to one ; and Mr. Walsh, who informed me of this statement, says
that with P. turnm this is certainly the case. In South Africa, Mr. R.
Trimen found the males in excess in 19 species ; 76 and in one of these,
which swarms in opvn places, he estimated the number of males as
fifty to one female. With another species, in which the males are
numerous in certain localities, he collected only five females during
seven years. In the island of Bourbon, M. Maillard states that the
males of one species of Papilio are twenty times as numerous as the
females. 77 Mr. Trimen informs me that as far as he has himself seen,
or heard from others, it is rare for the females of any butterfly to
exceed the males in number; but three South African species per-
haps offer an exception. Mr. Wallace 78 states that the females of
Ornithoptera crossus, in the Malay archipelago, are more common and
more easily caught than the males ; but this is a rare butterfly. I may
73 Yarrell, * Hist. British Fishes,' or four times as numerous as the
irol. i. 1826, p. 307 ; on the Cyprinus females.
carpio, p. 331 ; on the Tinea vulgaris, 7S * The Naturalist on the Ama-
p. 331 ; on the Abramis brama, p. zons,' vol. ii. 1863, p. 228, 347-
336. See, for the minnow {Leu- 7e Four of these cases are given
ciscus phoxinus), i Loudon's Mag. of by Mr. Trimen in his i Rhopaloeera
Nat. Hist.' vol. v. 1832, p. 682. Africa? Australis/
74 Leuckart quotes Meinecke " Quoted by Trimen, c Transact.
(Wagner, * Handworterbuch der Ent. Soc/ vol. v. part iv. 1866, p. 330,
Phys.' B. it. 1853, s. 775) that 78 'Transact. Linn. Soc,' vol, xxv.
the males of Butterflies are three p. 37.
Chap. VIII. Proportion of the Sexes. 25 1
bete add, that in Hyperythra, a genus of moths, Guenee says, that
from four to five females are sent in collections from India for one
male.
When this subject of the proportional numbers of the sexes of insects
was brought before the Entomological Society, 79 it was generally
admitted that the males of most Lepidoptera, in the adult or imago
state, are caught in greater numbers than the females : but this fact
was attributed by various observers to the more retiring habits of the
females, and to the males emerging earlier from the cocoon. This
latter circumstance is well known to occur with most Lepidoptera, as
well as with other insects. So that, as M. Personnat remarks, the
males of the domesticated Bombyx Yamamai, are useless at the begin-
ning of the season, and the females at the end, from the want of
mates. 80 I cannot, however, persuade myself that these causes suffice to
explain the great excess of males, in the above cases of certain butter-
flies which axe extremely common in their native countries. Mr.
Stainton, who has paid very close attention during many years to the
smaller moths, informs me that when he collected them in the imago
state, he thought that the males were ten times as numerous as the
females, but that since he has reared them on a large scale from the
caterpillar state, he is convinced that the females are the more
numerous. Several entomologists concur in this view. Mr. Double-
day, however, and some others, take an opposite view, and are con-
vinced that they have* reared from the eggs and caterpillars a larger
proportion of males than of females.
Besides the more active habits of the males, their earlier emergence
from the cocoon, and in some cases their frequenting more open
stations, other causes may be assigned for an apparent or real difference
in the proportional numbers of the sexes of Lepidoptera, when cap-
tured in the imago state, and when reared from the egg or caterpillar
Btate. I hear from Professor Canestrini, that it is believed by many
breeders in Italy, that the female caterpillar of the silk-moth suffers
more from the recent disease than the male ; and Dr. Staudinger
informs me that in rearing Lepidoptera more females die in the
cocoon than males. With many species the female caterpillar is larger
than the male, and a collector would naturally choose the finest
specimens, and thus unintentionally collect a larger number of females.
Three collectors have told me that this was their practice ; but Dr.
Wallace is sure that most collectors take all the specimens which they
can find of the rarer kinds, which alone are worth the trouble of
rearing. Birds when surrounded by caterpillars would probably
devour the largest ; and Professor Canestrini informs me that in Italy
some breeders believe, though on insuificient evidence, that in the first
broods of the Ailanthus silk-moth, the wasps destroy a larger number of
the female than of the male caterpillars. Dr. Wallace further remarks
that female caterpillars, from being larger than the males, require
more time for their development, and consume more food and mois
ture ; and thus they would be exposed during a longer time to
danger from ichneumons, birds, &c, and in times of scarcity would
perish in greater numbers. Hence it appears quite possible thai
79 ' Proc. Entomolog. Soc* Feb. 'Proc. Ent. Soc* 3rd sciieg, ▼©!, v
I7th, 1868. l8tJ7 ? l.487.
8C Quoted by Dr. Wallace in
252 The Descent of Man. Pam n.
in a state of nature, fewer female Lepidoptera may reach, maturity
than males ; and for our special object we are concerned with their
relative numbers at maturity, when the sexes are ready to propagate
their kind.
The manner in which the males of certain moths congregate in
extraordinary numbers round a single female, apparently indicates a
great excess of males, though this fact may perhaps be accounted for
by the earlier emergence of the males from their cocoons. Mr.
Stainton informs me that from twelve to twenty males, may often be
seen congregated round a female ElacMsta rufocinerea. It is well
known that if a virgin Lasiocampa quercus or Saturnia carpini
be exposed in a cage, vast numbers of males collect round her, and if
confined in a room will even come down the chimney to her. Mr
Doubleday believes that he has seen from fifty to a hundred males of
both these species attracted in the course of a single day by a female
in confinement. In the Isle of Wight Mr. Trimen exposed a box
in which a female of the Lasiocampa hud been confined on the
previous day, and five males soon endeavoured to gain admittance.
In Australia, M. Verreaux, having placed the female of a small
Bombyx in a box in his pocket, was followed by a crowd of males, so
that about 200 entered the house with him. 81
Mr. Doubleday has called my attention to M. Staudinger's 82 list
of Lepidoptera, which gives the prices of the males and females of
300 species or well-marked varieties of butterflies^Rhopalocera). The
prices for both sexes of the very common species are of course the same ;
but in 114 of the rarer species they differ; the males being in all cases,
excepting one, the cheaper. On an average of the prices of the 113 species,
the price of the male to that of the female is as 100 to 149 ; and this
apparently indicates that inversely the maks exceed the females in
the same proportion. About 2000 species or varieties of moths
(Heterocera) are catalogued, those with wingless females being here
excluded on account of the difference in habits between the two sexes :
of these 2000 species, 141 differ in price according to sex, the males
of 130 being cheaper, and those of only 11 being dearer than the
females. The average price of the males of the 130 species, to that of
the females, is as 100 to 143. With respect to the butterflies in this
priced list, Mr. Doubleday thinks (and no man in England has had
more experience), that there is nothing in the habits of the species
which can account for the difference in the prices of the two sexes,
and that it can be accounted for only by an excess in the number of
the males. But I am bound to add that Dr. Staudinger informs me,
that he is himself of a different opinion. He thinks that the less active
habits of the females and the earlier emergence of the males will
account for his collectors securing a larger number of males than
of females, and consequently for the lower prices of the former. With
respect to specimens reared from the caterpillar-state, Dr. Staudinger
believes, as previously stated, that a greater number of females than of
males die whilst confined in the cocoons. He adds that with certain
species one sex seems to preponderate over the other during certain
years.
Of direct observations on the sexes of Lepidoptera, reared either
•* Blanchard, ' Metamorphoses, 82 < Lepidopteren - Doublet^
MoEurs 4es Insect^,' 1368, pp, 2 .5- Lisfe/ Berlin, No. x. 18§§,
226
CiiAf. vul
Proportion of the Sexes.
m
from eggs or caterpillars, I have received only the few following
cases : —
Males. | Females-
The fiev. J. Hellins 83 of Exeter reared, during 1868,1!
imagos of 73 species, which consisted of. . . J
Mr. Albert Jones of Eltham reared, during 1868,^1
imagos of 9 species, which consisted of . . . J
During 1869 he reared imagos from 4 species, con-}
sisting of . J
Mr. Buckler of Emsworth, Hants, during 1869,}
reared imagos from 74 species, consisting of. . /
Dr. Wallace of Colchester reared from one brood of
Bombyx cynthia
Dr. Wallace raised, from cocoons of Bombyx PernyH
sent from China, during 1869 /
Dr. Wallace raised, during 1868 and 1869, from two\
lots of cocoons of Bombyx yama-mai . . . /
Total
153
137
159
126
114
112
180
169
52
48
224
123
52
46
934
761
So that in these eight lots of cocoons and eggs, males were produced
in excess. Taken together the proportion of males is as 122*7
to 100 females. But the numbers are hardly large enough to be
trustworthy.
On the whole, from these various sources of evidence, all pointing
in the same direction, I infer that with most species of Lepidoptera
the mature males generally exceed the females in number, whatever
the proportions may be at their first emergence from the egg.
With reference to the other Orders of insects, I have oeen able
to collect very little reliable information. With the stag-beetle
(Lucanus cervus) "the males appear to be much more numerous
" than the females ;" but when, as Cornelius remarked during 1867,
an unusual number of these beetles appeared in one part of Germany,
the females appeared to exceed the males as six to one. With one of
the Elateridse, the males are said to be much more numerous than the
females, and ** two or three are often found united with one female ; 84
** so that here polyandry seems to prevail." W r ith Siagonium (Staphy-
linidse), in which the males are furnished with horns, " the females are
44 far more numerous than the opposite sex." Mr. Janson stated at the
Entomological Society that the females of the bark- feeding Tomicus
viUosus are so common as to be a plague, whilst the males are so rare
us to be hardly known.
83 This naturalist has been so
kind as to send me some results
from former years, in which the
females seemed to preponderate;
but so many of the figures were
estimates,- that I fcund it impossible
% tabulate them.
84 Giinther's * Record of Zoo-
logical Literature,' 1867, p. 260.
On the excess of female Lucanus,
ibid.«p. 250. On the males of Luca-
nus in England, Westwood, * Modern
Class, of insects/ vol. i. p. 187. On
the Siagonium, ibid. p. 172.
254 *£}& Descent of Man. Par*! if.
It is hardly worth While saying anything about the proportion of
the sexes in certain species and even groups of insects, for the inah\»
are unknown or very rare, and the females are parthenogenetic, thar
is, fertile without sexual union; examples of this are afforded by
several of the Cynipidee. 85 In ail the gall-making Cynipidse known
to Mr. Walsh, the females are four or live times as numerous as the
males ; and so it is, as he informs me, with the gall-making Cecidomyiiae
(Diptera). With some common species of Saw-flies (Tenthredinse)
Mr. F. Smith has reared hundreds of specimens from larvae of all
sizes, but has never reared a single male : on the other hand, Curtis
says, 86 that with certain species (Athalia), bred by him, the males were
to the females as six to one ; whilst exactly the reverse occurred with
the mature insects of the same species caught in the fields. In the
family of Bees, Hermann Miiller, 87 collected a large number of
specimens of many species, and reared others from the cocoons, and
counted the sexes. He found that the males of some species greatly
exceeded the females in number ; in others the reverse occurred ; and
in others the two sexes were nearly equal. But as in most cases the
males emerge from the cocoons before the females, they are at the
commencement of the breeding season practically in excess. Miiller
also observed that the relative number of the two sexes in some
species differed much in different localities. But as H. Miiller has
himself remarked to me, these remarks must be received with
some caution, as one sex might more easily escape observation than
the other. Thus his brother Fritz Miiller has noticed in Brazil that
the two sexes of the same species of bee sometimes frequent different
kinds of flowers. With respect to the Orthoptera, I know hardly
anything about the relative number of the sexes : Korte, 88 however,
says that out of 500 locusts which he examined, the males were to
the females as five to six. With the Neuroptera, Mr. Walsh states
that in many, but by no means in all the species of the Odonatous
group, there is a great overplus of males : in the genus Hetaerina, also,
the males are generally at least four times as numerous as the females.
In certain species in the genus Gomphus the males are equally in
excess, whilst in two other species, the females are twice or thrice
as numerous as the males. In some European species of Psocus
thousands of females may be collected without a single * male, whilst
w4th other species of the same genus both sexes are common. 89 In
England, Mr. MacLachlan has captured hundreds of the female
Apatania muliebris, but has never seen the male; and of Boreus
hyemalis only four or five males have been seen here. 90 With most
of these species (excepting the Tenthredinae) there is at present no
evidence that the females are subject to parthenogenesis ; and thus we
see how ignorant we are of the causes of the apparent discrepancy in
the proportion of the two sexes.
In the other Classes of the Articulata I have been able to collect still
M Walsh, in * The American En- derheuschrecke,' 1828, p. 20.
tomologist,' vol. i. 1869, p. 103. 8B * Observations on N. American
F. Smith, * Record of Zoological Neuroptera/ by H. Hagen and B. D.
Literature/ 1867, p. 328. Walsh, < Proc. Ent. Soc. Phila-
86 * Farm Insects,' pp. 45-46. delphia,' Oct. 1863, pp. 168, 223,
* 7 * Anwendung der Darwinschen 239.
I^hre Verh. d. n. V. Jahrej. xxiv.* 9 * <Proc. Ent. Soc Louden,' Feb.
88 'Die Strieh, Zug oder Wan- 17,1868.
fliiAp. Vltl. Proportion dj the Sexes. 255
less information. With Spiders, Mr. Blackwall, who has careful I y
attended to thia class during many years, writes to me that the males
from their more erratic habits are more commonly seen, and therefore
appear more numerous. This is actually the case with a few species ;
but he mentions several species in six genera, in which the females
appear to be much more numerous than the males. 91 The small size of
the males in comparison with the females (a peculiarity which is some*
times carried to an extreme degree), and their widely different appear-
ance, may account in some instances for their rarity in collections. 92
Some of the lower Crustaceans are able to propagate their kind
asexually, and this will account for the extreme rarity of the males :
thus Von Siebold 93 carefully examined no less than 13,000 specimens of
Apus from twenty-one localities, and amongst these he found only
319 males. With some other forms (as Tanais and Cypris), as Fritz
Miiller informs me, there is reason to believe that the males are much
shorter-lived than the females ; and this would explain their scarcity,
supposing the two sexes to be at first equal in number. On the other
hand, Miiller has invariably taken far more males than females of the
DiastylidaB and of Cypridina on the shores of Brazil; thus with a
species in the latter genus, 63 specimens caught the same day included
57 males; but he suggests that this preponderance may be due tc
some unknown difference in the habits of the two sexes. With one
of the higher Brazilian crabs, namely a Gelasimus, Fritz Miillei
found the males to be more numerous than the females. According
to the large experience of Mr. 0. Spence Bate, the reverse seems tc
be the case with six common British crabs, the names of which he
has given me.
The proportion of the sexes in relation to natural selection.
There is reason to suspect that in some cases man has by
selection indirectly influenced his own sex-producing powers.
Certain women tend to produce during their whole lives more
children of one sex than of the other : and the same holds good
of many animals, for instance, cows and horses ; thus Mr. Wright
of Yeldersley House informs me that one of his Arab mares,
though put seven times to different horses, produced seven
fillies. Though I have very little evidence on this head, analogy
would lead to the belief, that the tendency to produce either
sex would be inherited like almost every other peculiarity, foi
instance, that of. producing twins ; and concerning the above
tendency a good authority, Mr. J. Downing, has communicated
to me facts which seem to prove that this does occur in certain
families of short-horn cattle. Col. Marshall 9 * has recently found
on careful examination that the Todas, a hill-tribe of India,
91 Another great authority with 0. P. Cambridge, as quoted h
respect to this class, Prof. Thorell of * Quarterly Journal of Science,
Upsala (' On European Spiders,' 1868, p. 429.
1889-70, part i. p. 205) speaks as if 93 * Beitrage zur Parthenogenesis,
female spiders were generally com- p. 174.
roon?r than the males. 94 'The Tcdas/ 1873. pp, i00
' ** 3*e, on this subject, Mr. Ill, 194, 190,
$$6 The Descent of Man. t»Aitf It
consist of 112 males and 84 females of all ages— that is in a ratio
of 133*3 males to 100 females. The Todas, who are polyandrous
in their marriages, during former times invariably practised
female infanticide ; but this practice has now been discontinued
for a considerable period. Of the children born within late years,
the males are more numerous than the females, in the proportion
of 124 to 100. Colonel Marshall accounts for this fact in the
following ingenious manner. " Let us for the purpose of illustra-
tion take three families as representing an average of the
" entire tribe ; say that one mother gives birth to six daughters
" and no sons ; a second mother has six sons only, whilst the
" third mother has three sons and three daughters. The first
" mother, following the tribal custom, destroys four daughters
" and preserves two. The second retains her six sons. The third
" kills two daughters and keeps one, as also her three sons. We
" have then from the three families, nine sons and three daughters,
" with which to continue the breed. But whilst the males
" belong to families in which the tendency to produce sons is
" great, the females are of those of a converse inclination. Thus
" the bias strengthens with each generation, until, as we find,
u families grow to have habitually more sons than daughters."
That this result would follow from the above form of infanticide
seems almost certain ; that is if we assume that a sex-producing
tendency is inherited. But as the above numbers are so ex-
tremely scanty, I have searched for additional evidence, but
cannot decide whether what I have found is trustworthy ;
nevertheless the facts are, perhaps, worth giving. The Maories of
New Zealand have long practised infanticide ; and Mr. Fenton 95
states that he " has met with instances of women who have de-
stroyed four, six, and even seven children, mostly females.
* However, the universal testimony of those best qualified to
" judge, is conclusive that this custom has for many years been
' '' almost extinct. Probably the year 1835 may be named as the
" period of its ceasing to exist." Now amongst the New Zea-
landers, as with the Todas, male births are considerably in excess.
Mr. Fenton remarks (p. 30), " 0n8 fact is certain, although the
" exact period of the commencement of this singular condition of
" the disproportion of the sexes cannot be demonstratively fixed,
" it is quite clear that this course of decrease was in full opera-
" tion during the years 1830 to 1844, when the non-adult
"population of 1844 was being produced, and has continued
" with great energy up to the present time." The following
statements are taken from Mr. Fenton (p. 26), but as the numbers
95 'Aboriginal Inhabitants of New Zealand; Government Report/ 1859,.
p, 'to.
Chap. VIII. Proportion of tlte Sexes. 257
are not large, and as the census was not accurate, uniform
results cannot be expected. It should be borne in mind in this
and the following cases, that the normal state of every population
is an excess of women, at least in all civilised countries, chiefly
owing to the greater mortality of the male sex during youth, and
partly to accidents of all kinds later in life. In 1858, the
native population of New Zealand was estimated as consisting
of 31,667 males and 24,303 females of all ages, that is in the
ratio of 130*3 males to 100 females. But during this same year,
and in certain limited districts, the numbers were ascertained
with much care, and the males of all ages were here 753
and the females 616 ; that is in the ratio of 122*2 males to 100
females. It is more important for us that during this same
year of 1858, the non-adult males within the same district
were found to be 178, and the non-adult females 142, that is in
the ratio of 125*3 to 100. It may be added that in 1844, at
which period female infanticide had only lately ceased, the
non-adult males in one district were 281, and the non-adult
females only 194, that is in the ratio of 144*8 males to 100 females.
In the Sandwich Islands, the males exceed the females in
number. Infanticide was formerly practised there to a frightful
sxtent, but was by no means confined to female infants, as
is shewn by Mr. Ellis, 96 and as I have been informed by Bishop
Staley and the Eev. Mr. Coan. Nevertheless, another apparently
trustworthy writer, Mr. Jarves, 97 whose observations apply to
the whole archipelago, remarks : — " Numbers of women are to
" be found, who confess to the murder of from three to six or eight
*' children f and he adds, " females from being considered less
" useful than males were more often destroyed/' From what is
known to occur in other parts of the world, this statement is
probable ; but must be received with much caution. The
practice of infanticide ceased about the year 1819, when idolatry
was abolished and missionaries settled in the Islands. A careful
census in 1839 of the adult and taxable men and women in the
island of Kauai and in one district of Oahu (Jarves, p. 404),
gives 4723 males and 3776 females; that is in the ratio of
125*08 to 100. At the same time the number of males under
fourteen years in Kauai and under eighteen in Oahu was 1797,
and of females of the same ages 1429 ; and here we have the
ratio of 125*75 males to 100 females.
In a census of all the islands in 1850, 98 the males of all ages
M ' Narrative of a Tour through •• This is given in the Rev. H. T*
Hawaii,* 1826, p. 298. Cheever's * Life in the Sandwich k-
91 « History of the Sandwich lands,' 1851, p. 277.
glands/ 1843, p. 93.
9-J
Tlie Descent of Man,
Past II,
amount to 36,272, and the females to 33,128, or as 109*49 to
100. The males under seventeen years amounted to 10,773, and
the females under the same age to 9593, or as 1123 to 100.
From the census of 1872, the proportion of males of all ages'
(including half-castes) to females, is as 125*36 to 100. It must
be borne in mind that all these returns for the Sandwich
Islands give the proportion of living males to living females,
and not of the births ; and judging from all civilised countries
the proportion of males would have been considerably higher it
the numbers had referred to births."
From the several foregoing cases we have some reason to
believe that infanticide practised in the manner above explained,
tends to make a male-producing race ; but I am far from sup-
posing that this practice in the case of man, or some analogous
process with other species, has been the sole determining cause
of an excess of males. There may be some unknown law leading
to this result in decreasing races, which have already become
somewhat infertile. Besides the several causes previously
99 Dr. Coulter, in describing
('Journal R. Geograph. Soc./ vol.
v. 1835, p. 67) the state of Cali-
fornia about the year 1830, says
that the natives, reclaimed by the
Spanish missionaries, have nearly
all perished, or are perishing, al-
though well treated, not driven
from their native land, and kept
from the use of spirits. He at-
tributes this, in great part, to the
undoubted fact that the men greatly
exceed the women in number ; but
he does not know whether this is
due to a failure of female offspring,
or to more females dying during
early youth. The latter alternative,
according to all analogy, is very
improbable. He adds that "in-
" fanticide, properly so called, is
"not common, though very fre-
" quent recourse is had to abor-
" tion." If Dr. Coulter is correct
about infanticide, this case cannot
be advanced in support of Col.
Marshall's view. From the rapid
decrease of the reclaimed natives,
we may suspect that, as in the
cases lately given, their fertility
has been diminished from changed
habits of life.
I had hoped to gain some light
on this subject from the breeding
of dogs ; inasmuch as in most breeds,
with the exception, perhaps, of
greyhounds, many more female
puppies are destroyed than males,
just as with the Toda infants. Mr.
Cupples assures me that this is
usual with Scotch deer-hounds.
Unfortunately, I know nothing ot
the proportion of the sexes in any
breed, excepting greyhounds, and
there the male births are to the
female as 110-1 to 100. Now from
enquiries made from many breeders,
it seems that the females are
in some respects more esteemed,
though otherwise troublesome ; and
it does not appear that the female
puppies of the best-bred dogs are
systematically destroyed more than
the males, though this does sometimes
take place to a limited extent. There-
fore I am unable to decide whether
we can, on the above principles, ac-
count for the preponderance of male
births in greyhounds. On the other
hand, we have seen that with
horses, cattle, and sheep, which are
too valuable for the young of either
sex to be destroyed, if there is any
difference, tha females are slightly
is excess
Chap. Yin, Proportion of the Sexes. 259
alluded to, the greater facility of parturition amongst savages,
and the less consequent injury to their male infants, would
tend to increase the proportion of live-born males to females.
There does not, however, seem to be any necessary connection
between savage life and a marked excess of males ; that is if we
may judge by the character of the scanty offspring of the lately
existing Tasmanians and of the crossed offspring of the Tahitians
now inhabiting Norfplk Island.
As the males and females of many animals differ somewhat in
habits and are exposed in different degrees to danger, it is
probable that in many cases, more of one sex than of the other
are habitually destroyed. But as far as I can trace out the com-
plication of causes, an indiscriminate though large destruction
of either sex would not tend to modify the sex-producing power
of the species. With strictly social animals, such as bees or ants,
which produce a vast number of sterile and fertile females in
comparison with the males, and to whom this preponderance is
of paramount importance, we can see that those communities
would flourish best which contained females having a strong
inherited tendency to produce more and more females; and in
such cases an unequal sex-producing tendency would be ulti-
mately gained through natural selection. With animals living
in herds or troops, in which the males come to the front and
defend the herd, as with the bisons of North America and certain
baboons, it is conceivable that a male-producing tendency might
be gained by natural selection; for the individuals of the better
defended herds would leave more numerous descendants. In
the case of mankind the advantage arising from having a pre-
ponderance of men in the tribe is supposed to be one chiof cause
of the practice of female infanticide.
In no case, as far as we can see, would an inherited tendency
to produce both sexes in equal numbers or to produce one sex
in excess, be a direct advantage or disadvantage to certain
individuals more than to others ; for instance, an individual
with a tendency to produce more males than females would not
succeed better in the battle for life than an individual with an
opposite tendency ; and therefore a tendency of this kind could
not be gained through natural selection. Nevertheless, there are
certain animals (for instance, fishes and cirripedes) in which two
or more males appear to be necessary for the fertilisation of the
female ; and the males accordingly largely preponderate, but it
is by no means obvious how this male-producing tendency could
have been acquired. I formerly thought that when a tendency
to produce the two sexes in equal numbers was advantageous to
the species, it WQuld follow from natural selection, but I now
• s 2
260 The Descent of Man. Part II.
see that the whole problem is so intricate that it is safer to leava
its solution for the future.
CHAPTEB IX.
Secondary Sexual Characters in the Lower Classes of
the Animal Kingdom.
These characters absent in the lowest classes — Brilliant colours — Molluscs
— Annelids — Crustacea, secondary sexual characters strongly developed ;
dimorphism ; colour ; characters not acquired before maturity — Spiders,
sexual colours of ; stridulation by the males — Myriapoda.
With animals belonging to the lower classes, the two sexes
are not rarely united in the same individual, and therefore
secondary sexual characters cannot be developed. In many
cases where the sexes are separate, both are permanently at-
tached to some support, and the one cannot search or struggle
for the other. Moreover it is almost certain that these animals
have too imperfect senses and much too low mental powers, to
appreciate each other's beauty or other attractions, or to feel
rivalry.
Hence in these classes or sub-kingdoms, such as the Protozoa,
Coelenterata, Echinodermata, Scolecida, secondary sexual cha-
racters, of the kind which we have to consider, do not occur; and
this fact agrees with the belief that such characters in the
higher classes have been acquired through sexual selection,
which depends on the will, desire, and choice of either sex.
Nevertheless some few apparent exceptions occur; thus, as I
hear from Dr. Baird, the males of certain Entozoa, or internal
parasitic worms, differ slightly in colour from the females ; but
we have no reason to suppose that such differences have been
augmented through sexual selection. Contrivances by which the
male holds the female, and which are indispensable for the
propagation of the species, are independent of sexual selection,
and have been acquired through ordinary selection.
Many of the lower animals, whether hermaphrodites or with
separate sexes, are ornamented with the most brilliant tints, or
are shaded and striped in an elegant manner ; for instance, many
corals and sea-anemones (ActinisB), some jelly-fish (MedussB,
Porpita, &c), some Planariee, many star-fishes, Echini, Ascidians,
&c. ; but we may conclude from the reasons already indicated,
namely the union of the two sexes in some of these animals, the
permanently affixed condition of others, and the low mental
powers of all, that such colours do not serve as a sexual
attraction, and have not been acquired through sexual selection.
Chap. IX. Sexual Selection. 261
It should be borne in mind that in no case have we suffi-
cient evidence that colours have been thus acquired, ex-
cept where one sex is much more brilliantly or conspicuously
coloured than the other, and where there is no difference
in habits between the sexes sufficient to account for their
different colours. But the evidence is rendered as complete
as it can ever be, only when the more ornamented indivi-
duals, almost always the males, voluntarily display their
attractions before the other sex ; for we cannot believe that such
display is useless, and if it be advantageous, sexual selection
will almost inevitably follow. We may, however, extend this
conclusion to both sexes, when coloured alike, if their colours are
plainly analogous to those of one sex alone in certain other
species of the same group.
How, then, are we to account for the beautiful or even
gorgeous colours of many animals in the lowest classes? It
appears doubtful whether such colours often serve as a protec-
tion ; but that we may easily err on this head, will be admitted
by every one who reads Mr. Wallace's excellent essay on this
subject. It would not, for instance, at first occur to any one
that the transparency of the Medusae, or jelly-fishes, is of the
highest service to them as a protection; but when we are
reminded by Hackel that not only the medusae, but many
floating mollusca, crustaceans, and even small oceanic fishes
partake of this same glass-like appearance, often accompanied
by prismatic colours, we can hardly doubt that they thus
escape the notice of pelagic birds and other enemies. M.
Giard is also convinced 1 that the bright tints of certain
sponges and ascidians serve as a protection. Conspicuous
colours are likewise beneficial to many animals as a warning to
their would-be devourers that they are distasteful, or that they
possess some special means of defence ; but this subject will be
discussed more conveniently hereafter.
We can, in our ignorance of most of the lowest aiiimals, only
say that their bright tints result either from the chemical
nature or the minute structure of their tissues, independently ot
any benefit thus derived. Hardly any colour is finer than that
of arterial blood; but there is no reason to suppose that the
colour of the blood is in itself any advantage; and though it
adds to the beauty of the maiden's cheek, no one will pretend
that it has been acquired for this purpose. So again with many
animals, especially the lower ones, the bile is richly coloured ;
thus, as I am informed by Mr. Hancock, the extreme beauty of
the Eolidae (naked sea-slugs) is chiefly due to the biliary glzn.'la
1 'Archives de Zoclog. Exp^r./ Oct. 1872, p. 563.
262 The Descent of Man, Part IL
being seen through the translucent integuments — this beauty
being probably of no service to these animals. The tints of the
decaying leaves in an American forest are described by every
one as gorgeous; yet no one supposes that these tints are
of the least advantage to the trees. Bearing in mind how many
substances closely analogous to natural organic compounds have
been recently formed by chemists, and which exhibit the most
splendid colours, it would have been a strange fact if substances
similarly coloured had not often originated, independently of
any useful end thus gained, in the complex laboratory of living
organisms.
The sub-kingdom of the Mollusca. — Throughout this great
division of the animal kingdom, as far as I can discover,
secondary sexual characters, such as we are here considering,
lever occur. Nor could they be expected in the three lowest
classes, namely in the Ascidians, Polyzoa, and Brachiopods
(constituting the Molluscoida of some authors), for most of
these animals are permanently affixed to a support or have their
sexes united in the same individual. In the Lamellibranchiata,
or bivalve shells, hermaphroditism is not rare. In the next
higher class of the Gasteropoda, or univalve shells, the sexes are
either united or separate. But in the latter case the males
never possess special organs for finding, securing, or charming
the females, or for fighting with other males. As I am informed
by Mr. Gwyn Jeffreys, the sole external difference between the
sexes consists in the shell sometimes differing a little in form ;
for instance, the shell of the male periwinkle (Littorina littorea)
is narrower and has a more elongated spire than that of the
female. But differences of this nature, it may be presumed, are
directly connected with the act of reproduction, or with the
development of the ova.
The Gasteropoda, though capable of locomotion and furnished
with imperfect eyes, do not appear to be endowed with sufficient
mental powers for the members of the same sex to struggle
together in rivalry, and thus to acquire secondary sexual
characters. Nevertheless with the pulmoniferous gasteropods, or
land-snails, the pairing is preceded by courtship; for these
animals, though hermaphrodites, are compelled by their structure
to pair together. Agassiz remarks, 2 tf Quiconque a eu Poccasion
" d'observer les amours des limacons, ne saurait mettre en doute
" la seduction deployee dans les mouvements et les allures qui
" preparent et accomplissent le double embrassement de ces
" hermaphrodites." These animals appear also susceptible of
Borne degree of permanent attachment : an accurate observer,
2 * De l'Espeee et de la Class/ &c, 1869, p. 106.
Chap. IX. Molluscs. 263
Mr. Lonsdale, informs me that lie placed a pair of land-snails,
{Helix pomatia), one of which was weakly, into a small and ill-
provided garden. After a short time the strong and healthy
individual disappeared, and was traced by its track of slime
over a wall into an adjoining well-stocked garden. Mr.
Lonsdale concluded that it had deserted its sickly mate; but
after an absence of twenty-four hours it returned, and apparently
communicated the result of its successful exploration, for both
then started along the same track and disappeared over the
wall.
Even in the highest class of th.9 Mollusca, the Cephalopoda or
cuttlefishes, in which the sexes are separate, secondary sexual
characters of the present kind do not, as far as I can discover,
occur. This is a surprising circumstance, as these animals
possess highly-developed sense-organs and have considerable
mental powers, as will be admitted by every one who has watched
their artful endeavours to escape from an enemy. 8 Certain
Cephalopoda, however, are characterised by one extraordinary
sexual character, namely, that the male element collects within
one of the arms or tentacles, which is then cast off, and clinging
by its sucking-discs to the female, lives for a time an independent
life. So completely does the cast-off arm resemble a separate
animal, that it was described by Cuvier as a parasitic worm
under the name of Hectocotyle. But this marvellous structure
may be classed as a primary rather than as a secondary sexual
character.
Although with the Mollusca sexual selection does not seem to
have come into play; yet many univalve and bivalve shells,
such as volutes, cones, scallops, &c, are beautifully coloured
and shaped. The colours do not appear in most cases to be of
any use as a protection; they are probably the direct result, as
in the lowest classes, of the nature of the tissues; the patterns
and the sculpture of the shell depending on its manner of
growth. The amount of light seems to be influential to a certain
extent; for although, as repeatedly stated by Mr. Gwyn Jeffreys,
the shells of some species living at a profound depth are brightly
coloured, yet we generally see the lower surfaces, as well as the
parts covered by the mantle, less highly-coloured than the
upper and exposed surfaces * In some cases, as with shells
3 See, for instance, the account influence of light on the colours of
which I have given in my ' Journal a frondescent incrustation, de-
of Researches/ 1845, p. 7. posited by the surf on the coast-
4 I have given (' Geolog. Obser- rocks of Ascension, and formed by
rations on Volcanic Islands,* 1844, the solution of triturated sea-sh^U»*
p. 53) a curious instance of the
264 The Descent of Man. Fart It
living amongst corals or brightly-tinted sea-weeds, the bright
colours may servs as a protection. 5 But that many of the nudi-
branch mollusca, or sea-slugs, are as beautifully coloured as any
shells, may be seen in Messrs. Alder and Hancock's magnificent
work ; and from information kindly given me by Mr. Hancock,
it seems extremely doubtful whether these colours usually serve
as a protection. With some species this may be the case, as with
one kind which lives on the green leaves of algae, and is itself
bright-green. But many brightly-coloured, white or otherwise
conspicuous species, do not seek concealment ; whilst again some
equally conspicuous species, as well as other dull-coloured kinds,
live under stones and in dark recesses. So that with these nudi-
branch molluscs, colour apparently does not stand in any close
relation to the nature of the places which they inhabit.
These naked sea-slugs are hermaphrodites, yet they pair
together, as do land-snails, many of which have extremely
pretty shells. It is conceivable that two hermaphrodites,
attracted by each other's greater beauty, might unite and leave
offspring which would inherit their parents' greater beauty".
But with such lowly-organised creatures this is extremely
improbable. Nor is it at all obvious how the offspring from the
more beautiful pairs of hermaphrodites would have any ad-
vantage over the offspring of the less beautiful, so as to increase
in number, unless indeed vigour and beauty generally coincided.
We have not here the case of a number of males becoming
mature before the females, with the more beautiful males
selected by the more vigorous females. If, indeed, brilliant
colours were beneficial to a hermaphrodite animal in relation
to its general habits of life, the more brightly-tinted individuals
would succeed best and would increase in number; but this
would be a case of natural and not of sexual selection.
Sub-kingdom of the Vermes: Class, Annelida (or Sea-worms). —
In this class, although the sexes, when separate, sometimes
differ from each other in characters of such importance that they
have been placed under distinct genera or even families, yet the
differences do not seem of the kind which can be safely at-
tributed to sexual selection. These animals are often beauti-
fully coloured, but as the sexes do not differ in this respect, we
are but little concerned with them. Even the Nemertians,
though so lowly organised, "vie in beauty and variety of
u colouring with any other group in the invertebrate series;" yet
5 Dr. Morse has lately discussed 'Proc. Boston Soc. of Nat. Hist.'
this subject in his paper on the vol, xiv., April, 1871,
Adaptive Coloration of Mollusca,
Chap. IX. Crtistaceans* 265
Dr. Mcintosh 6 cannot discover that these colours are of any
service. The sedentary annelids become duller-coloured, ac-
cording to M. Quatrefages, 7 after the period of reproduction ; and
this I presume may be attributed to their less vigorous condition
at that time. All these worm-like animals apparently stand too
low in the scale for the individuals of either sex to exert any
choice in selecting a partner, or for the individuals of the same
sex to struggle together in rivalry.
Sub-kingdom of the Arthropoda: Class, Crustacea. — In this great
class we first meet with undoubted secondary sexual characters,
often developed in a remarkable manner. Unfortunately the
habits of crustaceans are very imperfectly known, and we cannot
explain the uses of many structures peculiar to one sex. With the
lower parasitic species the males are of small size, and they
alone are furnished with perfect swimming-legs, antennas and
sense-organs ; the females being destitute of these organs, with
their bodies often consisting of a mere distorted mass. But
these extraordinary differences between the two sexes are no
doubt related to ^heir widely different habits of life, and con-
sequently do not concern us. In various crustaceans, belonging to
distinct families, the anterior antennse are furnished with peculiar
thread-like bodies, which are believed to act as smelling-organs,
and these are much more numerous in the males than in the
females. As the males, without any unusual development of
their olfactory organs, would almost certainly be able sooner or
later to find the females, the increased number of the smelling-
threads has probably been acquired through sexual selection, by
the better provided males having been the more successful in
finding partners and in producing offspring. Fritz Miiller has
described a remarkable dimorphic species of Tanais, in which the
male is represented by two distinct forms, which never graduate
into each other. In the one form the male is furnished with
more numerous smelling-threads, and in the other form with
more powerful and more elongated chelsB or pincers, which serve
to hold the female. Fritz Miiller suggests that these differences
between the two male forms of the same species may have
originated in certain individuals having varied in the number of
the smelling-threads, whilst other individuals varied in the
shape and size of their chelae ; so that of the former, those which
were best able to find the female, and of the latter, those which
* See his beautiful monograph on 7 See M. Perrier, * l'Origine cU
* British Annelids,* part i. 1873, l'Homme d'apres Darwin/ ' Keren
*. * Scientifique,* Feb. 1873, p. 866'.
266
The Descent of Man.
Part It.
were best able to hold her, have left the greatest number of
progeny to inherit their respective advantages. 8
In some of the lower crustaceans, the right anterior antenna
of the male differs greatly in structure
from the left, the latter resembling in
its simple tapering joints the antennas
of the female. In the male the
modified antenna is either swollen in
the middle or angularly bent, or
converted (fig. 4) into an elegant,
and sometimes wonderfully complex,
prehensile organ. 9 It serves, as I hear
from Sir J. Lubbock, to hold the
female, and for this same purpose one
of the two posterior legs (b) on the
same side of the body is converted
into a forceps. In another family the
inferior or posterior antennas are
"curiously zigzagged" in the males
alone.
In the higher crustaceans the an-
terior legs are developed into chelse
or pincers; and these are generally
larger in the male than in the female,
— so much so that the market value of
the male edible crab (Cancer pagurus),
according to Mr. C. Spence Bate, is
five times as great as that of the fe-
male. In many species the chelae are
of unequal size on the opposite side of
the body, the right-hand one being, as
I am informed by Mr. Bate, generally,
though not invariably, the largest. This inequality is also often
much greater in the male than in the female. The two chelse
of the male often differ in structure (figs. 5, 6, and 7), the
smaller one resembling that of the female. What advantage is
gained by their inequality in size on the opposite sides of the
4. Labidocera Darwinii
(from Lubbock).
a. Part of right anterior an-
tenna of male, forming a
prehensile organ.
h. Posterior pair of thoracic legs
of male.
c. Ditto of female.
8 * Facts and Arguments for
Darwin/ English translat. 1869, p.
20. See the previous discussion on
the olfactory threads. Sars has
described a somewhat analogous
case (as quoted in 'Nature,' 1870,
p. 455) in a Norwegian crustacean,
the Pontoporeia affinis.
9 See Sir J. Lubbock in ' Annals
and Mag. of Nat. Hist/ vol. xi.
1853, pi. i. and x. ; and vol. xii.
(1853) pi. vii. See also Lubbock in
* Transact. Ent. Soc/ vol. iv. new
series, 1856-1858, p. 8. With re-
spect to the zig-zagged antennae
mentioned below, see Fritz Miiller,
' Facts and Arguments for Darwin/
1869, p. 40, foot-note.
Chap. IX.
Crustaceans.
207
body, and by the inequality being much greater in the male than
in the female; and why, when they are of equal size, both are
Fig. 5. Anterior part of body of Callianassa (from Milne-Edwards), showing the un-
equal and differently-constructed right and left-hand chelae of the male.
K.B — The artist by mistake has reversed the drawing, and made the left-hand chela
the largest.
Fig. 6.
Fig.*.
Fig. 6. Second leg ofmaleOrchestiaTucuratinga (from Fritz Mttller).
Fig. 1. Ditto of female. ■ ■ •
often much larger in the male than in the female, is not known.
As I hear from Mr. Bate, the cheise are sometimes of such length
and size that they cannot possibly be used for carrying food to the
mouth. In the males of certain fresh-water prawns (Palsemon)
the right leg is actually longer than the whole body. 10 The
graat size of the one leg with its chelae may aid the male in
fighting with his rivals; but this will not account for their
10 See a paper by Mr. C. Spence
Bate, with figures, in * Proc. Zoolosj.
Soc/ 1868, p. 363 ; and on the
nomenclature of the genus, ibid. p.
585. I am greatly indebted to Mr.
Spence Bate for nearly all the above
statements with respect to the chelse
of the higher crustaceans.
26S Tke Descent of Man. Part II.
inequality in the female on the opposite sides of of the body. In
Gelasimus, according to a statement quoted by Milne-Edwards, 11
the male and the female live in the same burrow, and this
shews that they pair ; the male closes the mouth of the burrow
with one of its chelae, which is enormously developed ; so that
here it indirectly serves as a means of defence. Their main use,
however, is probably to seize and to secure the female, and this
in some instances, as with Gammarus, is known to be the case.
The male of the hermit or soldier crab (Pagurus) for weeks
together, carries about the shell inhabited by the female. 12 The
sexes, however, of the common shore-crab (Carcinus meenas), afi
Mr. Bate informs me, unite directly after the female has moulted
her hard shell, when she is so soft that she would be injured if
seized by the strong pincers of the male ; but as she is caught
and carried about by the male before moulting, she could then be
seized with impunity.
Fritz Miiller states that certain species of Melita are distin-
guished from all other amphipods by the females having " the
' coxal lamellaB of the penultimate pair of feet produced into
m< hook-like processes, of which the males lay hold with the
" hands of the first pair." The development of these hook-like
processes has probably followed from those females which were
the most securely held during the act of reproduction, having
left the largest number of offspring. Another Brazilian amphi-
pod (Orchestia Darw-lnii, fig. 8) presents a case of dimorphism,
Like that of Tanais ; for there are two male forms, which differ
in the structure of their chelae. 13 As either chela would certainly
suffice to hold the female, — for both are now used for this purpose,
- — the two male forms probably originated by some having varied
in one manner and some in another; both forms having derived
certain special, but nearly equal advantages, from their differently
shaped organs.
It is not known that male crustaceans fight together for the
possession of the females, but it is probably the case ; for with
most animals when the male is larger than the female, he seems
to owe his greater size to his ancestors having fought
with other males during many generations. In most of the
orders, especially in the highest or the Brachyura, the male is
larger than the female ; the parasitic genera, however, in which
the sexes follow different habits of life, and most of the Ento-
mostraca must be excepted. The chelae of many crustaceans are
11 * Hist. Nat. des Crust.' torn. ii. of S. Devon/
1837, p. 50. 13 Fritz Miiller, * Facts and Argit*
12 Mr. C. Spence Bate, « Brit, ir.ents for Darwin/ 1869, pp. 25-28
Assoc., Fourth Report on the Fsuna
Chap. IX.
Crustaceans.
269
weapons well adapted for fighting. Thus when a Devil-crab
(Portunus puber) was seen by a son of Mr. Bate fighting with a
Carcinus mcenas, the latter was soon thrown on its back, and had
every limb torn from its body. When several males of a Brazilian
Gelasimus, a species furnished with immense pincers, were
placed together in a glass vessel by Fritz Muller, they mutilated
and killed one another. Mr. Bate put a large male Carcinus
Fig. 8. Orchestia Darwinii (from Fritz Muller), showfng the differently-constracleel
chelse of the two male forms.
mcenas into a pan of water, inhabited by a female which was
paired with a smaller male ; but the latter was soon dispossessed.
270 The Descent of Man. Part II.
Mr. Bate adds, " if they fought, the victory was a bloodless one,
" for I saw no wounds." This same naturalist separated a male
sand-skipper (so common on our sea-shores), Gammarus marlnus,
from its female, both of whom were imprisoned in the same
vessel with many individuals of the same species. The female,
when thus divorced, soon joined the others. After a time the
male was put again into the same vessel ; and he then, after
swimming about for a time, dashed into the crowd, and without
any fighting at once took away his wife. This fact shews that
in the Amphipoda, an order low in the scale, the males and
females recognise each other, and are mutually attached.
The mental powers of the Crustacea are probably higher than
at first sight appears probable. Any one who tries to catch one
of the shore-crabs, so common on tropical coasts, will perceive
how wary and alert they are. There is a targe crab (Birgns
latro), found on coral islands, which makes a thick bed of the
picked fibres of the cocoa-nut, at the bottom of a deep burrow.
It feeds on the fallen fruit of this tree by tearing off the husk,
fibre by fibre ; and it always begins at that end where the three
eye-like depressions are situated. It then breaks through one of
these eyes by hammering with its heavy front pincers, and
turning round, extracts the albuminous core with its narrow
posterior pincers. But these actions are probably instinctive, so
that they would be performed as well by a young animal as by
an old one. The following case, however, can hardly be so con-
sidered : a trustworthy naturalist, Mr. Gardner, 14 whilst watching
a shore-crab (Gelasimus) making its burrow, threw some shells
towards the hole. One rolled in, and three other shells remained
within a few inches of the mouth. In about five minutes the
crab brought out the shell which had fallen in, and carried it
away to the distance of a foot ; it then saw the three other shells
lying near, and evidently thinking that they might likewise roll
in, carried them to the spot where it had laid the first. It
would, I think, be difficult to distinguish this act from one
performed by man by the aid of reason.
Mr. Bate does not know of any well-marked case of difference
of colour in the two sexes of our British crustaceans, in which
respect the sexes of the higher animals so often differ. In some
cases, however, the males and females differ slightly in tint, but
Mr. Bate thinks not more than may be accounted for by their
different habits of life, such as by the male wandering more
about, and being thus more exposed to the light. Dr. Power
14 * Travels in the Interior of 463, an account of the habits of the
Brazil/ 1846, p. 111. I have given, Birgns.
in my * Journal of Kesearches/ p.
Chap. IX. Crustaceans. 2JX
tried to distinguish by colour the sexes of the several species
which inhabit the Mauritius, but failed, except with one species
of Squilla, probably S. stylif era, the male of which is described as
being " of a beautiful bluish-green/' with some of the appendages
chorry-red, whilst the female is clouded with brown and grey,
" with the red about her much less vivid than in the male." 15
In this case, we may suspect the agency of sexual selection.
From M. Bert's observations on Daphnia, when placed in a vessel
illuminated by a prism, we have reason to believe that even the
lowest crustaceans can distinguish colours. With Saphirina (an
oceanic genus of Entomostraca), the males are furnished with
minute shields or cell-like bodies, which exhibit beautiful
changing colours ; these are absent in the females, and in
both sexes of one species. 16 It would, however, be extremely
rash to conclude that these curious organs serve to attract the
females. I am informed by Fritz Miiller, that in the female of a
Brazilian species of Gelasiinus, the whole body is of a nearly
uniform greyish-brown. In the male the posterior part of the
cephalo-thorax is pure white, with the anterior part of a rich
green, shading into dark brown ; and it is remarkable that these
colours are liable to change in the course of a few minutes — the
white becoming dirty grey or even black, the green " losing much
" of its brilliancy." It deserves especial notice that the males do
not acquire their bright colours UDtil they become mature. They
appear to be much more numerous than the females; they
differ also in the larger size of their chelae. In some species of
the genus, probably in all, the sexes pair and inhabit the same
burrow. They are also, as we have seen, highly intelligent
animals. From these various considerations it seems probable
that the male in this species has become gaily ornamented in
order to attract or excite the female.
It has just been stated that the male Gelasimus does not
acquire his conspicuous colours until mature and nearly ready
to breed. This seems a general rule in, the whole class in respedt
to the many remarkable structural differences between the sexes.
We shall hereafter find the same law prevailing throughout the
great sub-kingdom of the Vertebrata ; and in all cases it is
eminently distinctive of characters which have been acquired
through sexual selection. Fritz Miiller 17 gives some striking
instances of this law; thus the male sand-hopper (Orchestia)
does not, until nearly full grown, acquire his large claspers,
15 Mr. Oh. Fraser, in 'Proc. Zoo- M Clans, 'Die freilebenden Cope-
log. Soc.' 1869, p. 3. I am indebted poden,' 1863, s. 35.
to Mr. Bate for Dr. Power's state- " * Facts and Arguments/ &c«
ment. 'P. 79.
272 The Descent of Mam Part IL
which aie very differently constructed from those of the female ;
whilst young, his claspers resemble those of the female.
Class, Arachnida (Spiders).— The sexes do not generally differ
much in colour, but the males are often darker than the females,
ns may be seen in Mr. Blackwall's magnificent work. 18 In some
species, however, the difference is conspicuous : thus the female
of Sparassus smaragdulus is dullish green, whilst the adult male
has the abdomen of a fine yellow, with three longitudinal stripes
of rich red. In certain species of Thomisus the sexes closely
resemble each other, in others they differ much ; and analogous
cases occur in many other genera. It is often difficult to say
which of the two sexes departs most from the ordinary coloration
of the genus to which the species belong ; but Mr. Blackwall
thinks that, as a general rule, it is the male ; and Canestrini w
remarks that in certain genera the males can be specifically dis-
tinguished with ease, but the females with great difficulty. I am
informed by Mr. Blackwall that the sexes whilst young usually
resemble each other ; and both often undergo great changes in
colour during their successive moults, before arriving at maturity.
In other cases the male alone appears to change colour. Thus
the male of the above bright-coloured Sparassus at first re-
sembles the female, and acquires his peculiar tints only when
nearly adult. Spiders are possessed of acute senses, and exhibit
much intelligence; as is well known, the females often shew
the . strongest affection for their eggs, which they carry about
enveloped in a silken web. The males search eagerly for the
females, and have been seen by Canestrini and others to fight for
possession of them. This same author says that the union of the
two sexes has been observed in about twenty species ; and he
asserts positively that the female rejects some of the males who
court her, threatens them with open mandibles, and at last after
long hesitation accepts the chosen one. From these several
considerations, we may admit with some confidence that the
well-marked differences in colour between the sexes of certain
species are the results of sexual selection ; though we have not
here the best kind of evidence, — the display by the male of his
ornaments. From the extreme variability of colour in the male
of some species, for instance of Theridion lineatum, it would
appear that these sexual characters of the males have not as yet
become well fixed. Canestrini draws the same conclusion from
18 ' A History of the Spiders of ' Caratteri sessuali secondarii de^^i
Gfroat Britain,' 1861-64. For the Arachnidi/ in the 'Atti della Soc,
following facts, see pp. 77, 88, 102. Veneto-Trentina di Sc. Nat. Padora,
13 This author has recently pub- vol. i. Fasc. 3, 1873,
iisb^d a ▼ala&ble essay on the
Ghap. IX. Spiders. 273
the fact that the males of certain species present two forms,
differing from each other in the size and length of their jaws ; and
this reminds us of the above cases of dimorphic crustaceans.
The male is generally much smaller than the female, sometimes
to an extraordinary degree,' 20 and he is forced to be extremely
cautious in making his advances, as the female often carries her
coyness to a dangerous pitch. De Geer saw a male that " in the
" midst of his preparatory caresses was seized by the object of
" his attentions, enveloped by her in a web and then devoured, a
" sight which, as he adds, filled him with horror and indignation." 21
The Kev. 0. P. Cambridge 22 accounts in the following manner
for the extreme smallness of the male in the genus Nephila.
" M. Vinson gives a graphic account of the agile way in which
" the diminutive male escapes from the ferocity of the female, by
" gliding about and playing hide and seek over her body and
" along her gigantic limbs : in such a pursuit it is evident that
" the chances of escape would be in favour of the smallest males,
" while the larger ones would fall early victims ; thus gradually
" a diminutive race of males would be selected, until at last they
" would dwindle to the smallest possible size compatible with the
" exercise of their generative functions, — in fact probably to the
" size we now see them, i.e., so small as to be a sort of parasite
" upon the female, and either beneath her notice, or too agile and
" too small for her to catch without great difficulty."
Westring has made the interesting discovery that the males
of several species of Theridion 23 have the power of making
a stridulating sound, whilst the females are mute. The ap-
paratus consists of a serrated ridge at the base of the abdomen,
against which the hard hinder part of the thorax is rubbed ; and
of this structure not a trace can be detected in the females. It
deserves notice that several writers, including the well-known
arachnologist Walckenaer, have declared that spiders are attracted
by music. 24 From the analogy of the Orthoptera and Homoptera,
29 Aug. Vinson (* Aran&des des tion to Entomology/ vol. i. 1818,
lies de la Reunion,' pi. vi. figs. 1 p. 280.
and 2) gives a good instance of the 22 'Proc.Zoolog. Soc' 1871, p. 621.
small size of the male, in Epeira 23 Theridion (Asagena, Sund.)
nigra. In this species, as I may serratipes, 4~punctatum et gutta-
add, the male is testaceous and the turn ; see Westring, in Kroyer,
female black with legs banded with * Naturhist. Tidskrift/ vol. iv. 1842-
red. Other even more striking 1843, p. 349; and vol. ii. 1846-
cases of inequality in size between 1849, p. 342. See, also, for other
the sexes have been recorded species, * Araneae Suecicae,' p. 184.
(* Quarterly Journal of Science,* 2 * Dr. H. H. van Zouteveen, in
1868, July, p. 429); but I have his Dutch translation of this work
Mot seen the original accounts. (vol. i. p. 444), has collected sevai'ai
tl Jftrhy and Spence, i lutroduc- cases.
T
274 The Descent of Man. Part II,
to be described in the next chapter, we may feel almost sure that
the stridulation serves, as Westring also believes, to call or to
excite the female ; and this is the first case known to me in the
ascending scale of the animal kingdom of sounds emitted for
this purpose. 25
Class, Myriapoda. — In neither of the two orders in this class,
the millipedes and centipedes, can I find any well-markea
instances of such sexual differences as more particularly concern
us. In Qlomeris limbata, however, and perhaps in some few
other species, the males differ slightly in colour from the females ;
but this Glomeris is a highly variable species. In the males of
the Diplopoda, the legs belonging either to one of the anterior or
of the posterior segments of the body are modified into pre-
hensile hooks which serve to secure the female. In some species
of lulus the tarsi of the male are furnished with membranous
suckers for the same purpose. As we shall see when we treat
of Insects, it is a much more unusual circumstance, that it i3
the female in Lithobius, which is furnished with prehensile
appendages at the extremity of her body for holding the male. 26
CHAPTER X.
Secondary Sexual Characters op Insects.
Diversified structures possessed by the males for seizing the females —
Differences between the sexes, cf which the meaning is not understood —
Difference in size between the sexes — Thysanura — Diptera — Hemiptera
— Homoptera, musical powers possessed by the males alone — Orthoptera,
musical instruments of the males, much diversified in structure ;
pugnacity; colours — Neuroptera, sexual differences in colour — Hyme-
noptera, pugnacity and colours— Coleoptera, colours; furnished with
great horns, apparently as an ornament ; battles ; stridulating organs
generally common to both sexes.
In the immense class of insects the sexes sometimes differ in
their locomotive-organs, and often in their sense-organs, as in
the pectinated and beautifully plumose antennae of the males of
many species. In Chloeon, one of the Epbemeree, the male has
great pillared eyes, of which the female is entirely destitute. 1
The ocelli are absent in the females of certain insects, as in the
2S Hilgendcrf, however, has lately * Hist. Nat. des Insectes : Apteres,*
called attention to an analogous torn. iv. 1847, pp. 17, 19, 68.
structure in some of the higher l Sir J. Lubbock, ' Transact,
crustaceans, which seems adapted Linnean Soc.' vol. xxv. 1866, p.
to produce sound; see * Zoological 484. With respect to the Mu-
Record,* 1869, p. 603. tillidae see Westwood, * Modern
3 * W>lckenaer et P. Gexvais, Class, of Insects,* vol. ii. p. 213.
Chap. X. Insects. 275
Mutillidae; and here the females are likewise wingless. Brit
we are chiefly concerned with structures by which one male is
enabled to conquer another, either in battle or courtship, through
his strength, pugnacity, ornaments, or music. The innumerable
contrivances, therefore, by which the male is able to seize the
female, may be briefly passed over. Besides the complex structures
at the apex of the abdomen, which ought perhaps to be ranked
as primary organs, 2 "it is astonishing," as Mr. B. D. Walsh 3 has
remarked, " how many different organs are worked in by nature
" for the seemingly insignificant object of enabling the male to
. " grasp the female firmly." The mandibles or jaws are some-
times used for this purpose ; thus the male Corydalis comutus (a
neuropterous insect in some degree allied to the Dragon-flies, &c.)
has immense curved jaws, many times longer than those of the
female ; and they are smooth instead of being toothed, so that
. he is thus enabled to seize her without injury. 4 One of the
stag-beetles of North America (Lucanus elaphus) uses his jaws,
which are much larger than those of the female, for the same
purpose, but probably likewise for fighting. In one of the
sand-wasps (Ammophila) the jaws in the two sexes are closely
alike, but are used for widely different purposes : the males, as
Professor Westwood observes, " are exceedingly ardent, seizing
" their partners round the neck with their sickle-shaped jaws;" 5
whilst the females use these organs for burrowing in sand-banks
and making their nests.
The tarsi of the front-legs are dilated in many male beetles, or
are furnished with broad cushions of hairs ; and in many genera
of water-beetles they are armed with a round flat sucker, so that
the male may adhere to the slippery body of the female. It is a
2 These organs in the male often species having been observed in
differ in closely-allied species, and union. Mr. MacLachlan informs
afford excellent specific characters, me (vide ' Stett. Ent. Zeitung,*
But their importance, from a func- 1867, s. 155) that when several
tional point of view, as Mr.' R. species of Phryganidae, which pre-
MacLachlan has remarked to me, sent strongly-pronounced differences
has probably been overrated. It of this kind, were confined together
nas been suggested, that slight dif- by Dr. Aug. Meyer, they coupled,
-ferences in these organs woulcf and one pair produced fertile oVa.
suffice to prevent the intercrossing * ' The Practical Entomologist,*
of well-marked varieties or incipient Philadelphia, vol. ii. May, 1867,
species, and would thus aid in their p. 88.
development. That this can hardly * Mr. Walsh, ibid. p. 107.
be the case, we may infer from the * 'Modern classification of In-
many recorded cases (see, for in- sects,' vol. ii. 1840, pp. 205, 206.
instance, Bronn, ' Geschichte der Mr. Walsh, who called my attention
Xatur,' B. ii. 1843, s. 164; and to the double use of the jaws, say*
Westwood, * Transact. Ent. Soc' that he has repeatedly observed}
toL iii. 1842, p. 195) of distinct this fact.
T 2
2^6
The Descent of Man.
Pabt II.
much more unusual circumstance that the female of some water-
beetles (Dytiscus) have their elytra deeply grooved, and in
Acilius sulcatus thickly set with hairs, as an aid to the male.
The females of some other water-
beetles (Hydroporus) have their
elytra punctured for the same
purpose. 6 In the male of Crabro
cribrarius (fig. 9), it is the tibia
which is dilated into a broad
horny plate, with minute mem-
braneous dots, giving to it a sin-
gular appearance like that of a
riddle. 7 In the male of Penthe
(a genus of beetles) a few of the
middle joints of the antennae are
dilated and furnished on the in-
ferior surface with cushions of hair,
exactly like those on the tarsi of
the Carabidse, " and obviously for
" the same end." In male dragon-
flies, "the appendages at the tip
" of the tail are modified in an
" almost infinite variety of curious
(i patterns to enable them to em-
" brace the neck of the female."
Lastly, in the males of many in-
sects, the legs are furnished with peculiar spines, knobs or
spurs ; or the whole leg is bowed or thickened, but this is by no
means invariably a sexual character ; or one pair, or all three
pairs are elongated, sometimes to an extravagant length. 8
The sexes of many species in all the orders present differences,
of which the meaning is not understood. One curious case is
that of a beetle (fig. 10), the male of which has the left mandible
much enlarged; bo that the mouth is greatly distorted. In
another Carabidous beetle, Eurygnathus, 9 we have the case,
6 We have here a curious and * Introduction to Entomology,' vol.
inexplicable case of dimorphism, for iii. 1826, p. 305.
Fig. 9. Crabro cribrarius. Upper figure,
male; lower figure, female.
some of the females of four Euro-
pean species of Dytiscus, and of
certain species of Hydroporus, have
their elytra smooth ; and no inter-
mediate gradations between the
sulcated or punctured, and the quite
smooth elytra have been observed.
See Dr. H. Schaum, as quoted in
the * Zoologist/ vol. v.-vi. 1847-48,
p. 1896. Also Kirby and Spcnce,
Westwood, 'Modern Class.' vol.
ii. p. 193. The following state-
ment about Penthe, and others in
inverted commas, are taken from
Mr. Walsh, * Practical Entomolo-
gist,' Philadelphia, vol. ii. p. 88.
8 Kirby and Spence, ' Introduct.'
&c, vol. iii. pp. 332-336.
a * Insecta Maderensia/ 1854 } p.
20.
Chap. X.
Insects.
w
unique as far as known to Mr. Wollaston, of the head of the
female being much broader and larger, though in a variable
degree, than that of the male. Any number
of such cases could be given. They abound
in the Lepidoptera: one of the most extra-
ordinary is that certain male butterflies
have their fore-legs more or less atrophied,
with the tibiae and tarsi reduced to mere ru-
dimentary knobs. The wings, also, in the two
sexes often differ in neuration, 10 and some-
times considerably in outline, as in the Ari-
coris epitus, which was shewn to me in the
British Museum by Mr. A. Butler. The males
of certain South American butterflies have
tufts of hair on the margins of the wings,
and horny excrescences on the discs of the
posterior pair. 11 In several British butter-
flies, as shewn by Mr. Wonfor, the males alone
are in parts clothed with peculiar scales.
The use of the bright light of the female
glow-worm has been subject to much discus-
sion. The male is feebly luminous, as are the
larvae and even the eggs. It has been sup-
posed by some authors that the light serves to
frighten away enemies, and by others to
guide the male to the female. At last, Mr.
Belt 12 appears to have solved the difficulty:
he finds that all the Lampyridse which he has
tried are highly distasteful to insectivorous
mammals and birds. Hence it is in accordance
with Mr. Bates' view, hereafter to be explained,
that many insects mimic the Lampyridse
closely, in order to be mistaken for them, and
thus to escape destruction. He further be-
lieves that the luminous species profit by
being at once recognised as unpalatable.
It is probable that the same explanation may be extended to the
74. Mr. Wonfor's observations are
quoted in * Popular Science Eeview,'
1868, p. 343.
12 ' The Naturalist in Nicaragua?
1874, pp. 316-320. On the phos-
phorescence of the eggs, see * Annals
and Mag. of Nat. Hist/ 1871/ Nov.,
p. 372.
Fig. 10. Taphroderes
distortus (much en-
larged). Upper fig-
ure, male ; lower
figure, female.
10 E. Douhleday, ' Annals and
Mag. of Nat. Hist/ vol. i. 1848, p.
379. I may add that the wings in
certain Hymenoptera (see Shuckard,
* Fossorial Hymenop/ 1837, pp. 39-
43) differ in neuration according to
sex.
11 H. W. Bates, jl Journal of
Froc. Linn. Soc/ vol. vi. 1862, p.
278 The Descent of Man. Part U.
Elates, both sexes of which are highly luminous. It is not
known why the wings of the female glow-worm have not been
developed ; but in her present state she closely resembles a
larva, and as larvae are so largely preyed on by many animals,
we can understand why she has been rendered so much more
luminous and conspicuous than the male ; and why the larvae
themselves are likewise luminous.
Difference in Size between the Sexes. — -With insects of all kinds
the males are commonly smaller than the females; and this
difference can often be detected even in the larval state. So
considerable is the difference between the male and female
cocoons of the silk-moth (Bombyx mori), that in France they are
separated by a particular mode of weighing. 18 In the lower
classes of the animal kingdom, the greater size of the females
seems generally to depend on their developing an enormous
number of ova ; and this may to a certain extent hold good with
insects. But Dr. Wallace has suggested a much more probable
explanation. He finds, after carefully attending to the develop-
ment of the caterpillars of Bombyx cynthia and yama?nai, and
especially to that of some dwarfed caterpillars reared from a
second brood on unnatural food, " that in proportion as the in-
" dividual moth is finer, so is the time required for its metamor-
phosis longer; and for this reason the female, which is the
" larger and heavier insect, from having to carry her numerous
" eggs, will be preceded by the male, which is smaller and has
" less to mature." H Now as most insects are short-lived, and as
they are exposed to many dangers, it would manifestly be ad-
vantageous to the female to be impregnated as soon as possible.
This end would be gained by the males being first matured in
large numbers ready for the advent of the females ; and this
again would naturally follow, as Mr. A. B. "Wallace has re-
marked, 16 through natural selection; for the smaller males
would be first matured, and thus would procreate a large
number of offspring which would inherit the reduced size of
their male parents, whilst tho larger males from being matured
later would leave fewer offspring.
There are, however, exceptions to the rule of male insects
being smaller than the females : and some of these exceptions are
intelligible. Size and strength would be an advantage to the
males, which fight for the possession of the females; and in
these cases, as with the stag-beetle (Lucanus), the males are
larger than the females. There are, however, other beetles
13 RoMnet, 'Vers k Soie/ 1848, vol. v. p. 486.
^ 207. is 'Journal of Proc. Ent. Sco
M ' Transact. Ent. Soc.' 3rd series, Feb. 4th, 1867, p. lxxi.
Chap. X. Thysanura. 279
winch are not known to fight together, of which the males
exceed the females in size; and the meaning of this fact is not
known; but in some of these cases, as with the huge Dynastes
and Megasoma, we can at least see that there would be no
necessity for the males to be smaller than the females, in order
to be matured before them, for these beetles are not short-lived,
and there would be ample time for the pairing of the sexes. So
again, male dragon-flies (Libellulidse) are sometimes sensibly
larger, and never smaller, than the females; 16 and as Mr.
MacLachlan believes, they do not generally pair with the females
until a week or fortnight has elapsed, and until they have
assumed their proper masculine colours. But the most curious
case, shewing on what complex and easily-overlooked relations,
so trifling a character as difference in size between the sexes
may depend, is that of the aculeate Hymenoptera ; for Mr. F.
Smith informs me that throughout nearly the whole of this
large group, the males, in accordance with the general rule, are
smaller than the females, and emerge about a week before them ;
but amongst the Bees, the males of Apis mellifica, Anthidium
manicatum, and Antkoplwra acervorum, and amongst the Fossores,
the males of the Methoca ichneumonides, are larger than the
females. The explanation of this anomaly is that a marriage
flight is absolutely necessary with these species, and the male
requires great strength and size in order to carry the female
through the air. Increased size has here been acquired in op-
position to the usual relation between size and the period of
development, for the males, though larger, emerge before the
smaller females.
We will now review the several Orders, selecting such facts
as more particularly concern us. The Lepidoptera (Butterflies
and Moths) will be retained for a separate chapter. •
Order, Thysanura. — The members of this lowly organized
order are wingless, dull-coloured, minute insects, with ugly,
almost misshapen heads and bodies. Their sexes do not differ
but they are interesting as shewing us that the males pay
sedulous court to the females even low down in the animal
scale. Sir J. Lubbock n says : " it is very amusing to see these
" little creatures (Smynthurus luteus) coquetting together. The
" male, which is much smaller than the female, runs round her,
" and they butt one another, standing face to face and moving
11 For this and other statements see p. 344.
on the size of the sexes, see Kirby 17 * Transact. Linnean Sofc* tf§L
and Spence, ibid. vol. iii. p. 300 ; xxvj. 1868, p. 29$.
on the duration of life in insects,
sSo The Descent of Man. Part IL
* backward and forward like two playful lambs. Then ths
" female pretends to run away and the male runs after her with
" a queer appearance of anger, gets in front and stands facing
" her again ; then she turns coyly round, but he, quicker and
" more active, scuttles round too, and seems to whip her
" with his antennae ; then for a bit they stand face to face,
" play with their antennas, and seem to be all in all to one
" another."
Order, Diptera (Flies). — The sexes differ little in colour. The
greatest difference, known to Mr. F. Walker, is in the genus
Bibio, in which the males are blackish or quite black, and the
females obscure brownish-orange. The genus Elaphomyia, dis-
covered by Mr. Wallace 18 in New Guinea., is highly remarkable,
as the males are furnished with horns, of which the females are
quite destitute. The horns spring from beneath the eyes, and
curiously resemble those of a stag, being either branched or pal-
mated. In one of the species, they equal the whole body in
length. They might be thought to be adapted for fighting, but
as in one species they are of a beautiful pink colour, edged with
black, with a pale central stripe, and as these insects have
altogether a very elegant appearance, it is perhaps more probable
that they serve as ornaments. That the males of some Diptera
fight together is certain ; for Prof. Westwood 19 has several times
seen this with the Tipulse. The males of other Diptera ap-
parently try to win the females by their music : H. Miiller *
watched for some time two males of an Eristalis courting a
female; they hovered above her, and flew from side to side,
making a high humming noise at the same time. Gnats and
mosquitoes (Culicidae) also seem to attract each other by hum-
ming ; and Prof. Mayer has recently ascertained that the hairs
On the antennas of the male vibrate in unison with the notes of a
tuning-fork, within the range of the sounds emitted by the female.
The longer hairs vibrate sympathetically with the graver notes,
and the shorter hairs with the higher ones. Landois also asserts
that he has repeatedly drawn down a whole swarm of gnats by
uttering a particular note. It may be added that the mental
faculties of the Diptera are probably higher than in most other in-
sects, in accordance with their highly developed nervous system. 21
18 * The Malay Archipelago/ vol. 21 See Mr. B. T. Lowne's interest-
ii. 1869, p. 313. . ing work, * On the Anatomy of the
19 4 Modern Classification of In- Blow-fly, Musca vomitoria/ 1870, p.
sects/ vol. ii. 1840, p. 526. 14. He remarks (p. 33) that, " the
20 Anwendung, &c, * Verh. d. n. " captured flies utter a peculiar
V. Jahrg.' xxix. p. 80. Mayer, in " plaintive note, and that this sountf
' American Naturalist/ 1874, p. 236. " causes other flies to disappear."
Chap. X, Hemiptera and Homoptera, 281
Order, Hemiptera (Field-Bugs).— Mr. J. W. Douglas, who has
particularly attended to the British species, has kindly given me
an account of their sexual differences. The males of some species
are furnished with wings, whilst the females are wingless ; tha
sexes differ in the form of their bodies, elytra, antennae and tarsi ;
but as the signification of these differences are unknown, they
may be here passed over. The females are generally larger and
more robust than the males. With British, and, as far as
Mr. Douglas knows, with exotic species, the sexes do not
commonly differ much in colour; but in about six British
species the male is considerably darker than the female, and
in about four other species the female is darker than the male.
Both sexes of some species are beautifully coloured; and as
these insects emit an extremely nauseous odour, their con-
spicuous colours may serve as a signal that they are unpalat-
able to insectivorous animals. In some few cases their colours
appear to be directly protective : thus Prof. Hoffmann informs
me that he could hardly distinguish a small pink and green
species from the buds on the trunks of lime-trees, which this
insect frequents.
Some species of Reduvidae make a stridulating noise ; and, in
the case of Pirates stridulus, this is said 22 to be effected by the
movement of the neck within the pro-thoracic cavity. Accord-
ing to Westring, Eeduvius personatus also stridulates. But I
have no reason to suppose that this is a sexual character, ex-
cepting that with non-social insects there seems to be no use
for sound-producing organs, unless it be as a sexual call.
Order, Eomoptera. — Every one who has wandered in a tropi-
cal forest must have been astonished at the din made by the
male Cicada. The females are mute; as the Grecian poet
Xenarchus says, " Happy the Cicadas live, since they all have
" voiceless wives." The noise thus made could be plainly heard
on board the " Beagle," when anchored at a quarter of a mile
from the shore of Brazil ; and Captain Hancock says it can be
heard at the distance of a mile. The Greeks formerly kept, and
the Chinese now keep these insects in cages for the sake of
their song, so that it must be pleasing to the ears of some men. 28
The Cicadidsa usually sing during the day, whilst the Fulgorid®
appear to be night-songsters. The sound, according to Landois, 2 *
22 Westwood, ' Modern Class, of also, on the Fulgoridae, Kirby and
Insects,' vol. ii. p. 473. Spence, ' Introduct.' vol. ii. p. 401.
i3 These particulars are taken 24 'Zeitschrift fdr wiss^nschaft
from Westwood's * Modern Class, of Zoolog.' B, xvii, 1867, 8. 152-158,
Insects,' toL ii 1840, p. 422. See,
282 The Descent of Man. Paet H,
is produced by the vibration ot the lips of the spiracles, which
are set into motion by a current of air emitted from the tracheae ;
but this view has lately been disputed. Dr. Powell appears to
have proved M that it is produced by the vibration of a mem-
brane, set into action by a special muscle. In the living insect,
whilst stridulating, this membrane can be seen to vibrate ; and
in the dead insect the proper sound is heard, if the muscle,
when a little dried and hardened, is pulled with the point of a
pin. In the female the whole complex musical apparatus is
present, but is much less developed than in the male, and is
never used for producing sound.
With respect to the object of the music, Dr. Hartman, in
speaking of the Cicada septemdecim of the United States, says, 2S
" the drums are now (June 6th and 7th, 1851) heard in all
" directions. This I believe to be the marital summons from
" the males. Standing in thick chestnut sprouts about as high
" as my head, where hundreds were around me, I observed the
" females ooming around the drumming males." He adds, " this
" season (Aug. 1868) a dwarf pear-tree in my garden produced
" about fifty larvae of Cic. pruinosa ; and I several times noticed
" the females to alight near a male while he was uttering his
" clanging notes." Fritz Miiller writes to me from S. Brazil
that he has often listened to a musical contest between two or
three males of a species with a particularly loud voice, seated
at a considerable distance from each other : as soon as one had
finished his song, another immediately began, and then another.
As there is so much rivalry between the males, it is probable
that the females not only find them by their sounds, but that,
like female birds, they are excited or allured by the male with
the most attractive voice.
I have not heard of any well-marked cases of ornamental
differences between the sexes of the Homoptera. Mr. Douglas
informs me that there are three British species, in which the
male is black or marked with black bands, whilst the females are
pale-coloured or obscure.
Order, Orthoptera (Crickets and Grasshoppers). — The males in
the three saltatorial families in this Order are remarkable for
tttelr ^wisical powers, namely the Achetidso or crickets, the
LocustidaB for which there is no equivalent English name, and the
Acridiidso or grasshoppers. The stridulation produced by some
,a 'Transact. New Zealand In- from a * Journal of the Doings of
sutnte,' vol. v. 1873, p. 286. Cicada septemdecim ' by Dr. Hart-
36 I am indebted to Mr. Walsh man.
for having sent me this extract
Ghap. X.
Orthoptera.
283
of the Locustidss is so loud that it can be heard during the night
at the distance of a mile; 27 and that made by certain species is
not unmusical even to the human ear, so that the Indians on the
Amazons keep them in wicker cages. All observers agree that
the sounds serve either to call or excite the mute females. "With
respect to the migratory locusts of Russia, K6rte has given 28 an
interesting case of selection by the female of a male. The males
of this species (Pachytylus migratorius) whilst coupled with the
female stridulate from anger or jealousy, if approached by other
males. The house-cricket when surprised at night uses its voice
to warn its fellows. 29 In North America the Katy-did (Platy-
phyllum concavmn, one ©f the Locustidse) is described 30 as mount-
ing on the upper branches of a tree, and in the evening beginning
" his noisy babble, while rival notes issue from the neighbouring
" trees, and the groves resound with the call of Katy-did-she-did
" the live-long night." Mr.
Bates, in speaking of the Euro-
pean field-cricket (one of the
Achetidse), says, " the male has
" been observed to place him-
" self in the evening at the
" entrance of his burrow, and
" stridulate until a female ap-
" proaches, when the louder
" notes are succeeded by a
" more subdued tone, whilst
" the successful musician ca-
" resses with his antennae the
" mate he has won." 31 Dr.
Scudder was able to excite one
of these insects to answer him,
by rubbing on a file with a
quill. 32 In both sexes a re-
markable auditory apparatus
has been discovered by Von Siebold, situated in the front legs. K
Fig. 11. Gryllus campestris (from Landois)*
Right-hand figure, under side of part of a
wing-nervure, much magnified, showing
the teeth, st.
Left-hand figure, upper surface of wing-
cover, with the projecting, smooth nervure,
r, across which the teeth (sf) are scraped.
27 L. Guilding, 'Transact Linn.
Soc.' vol. xv. p. 154.
28 I state this on the authority
of Koppen, ' Ueber die Heuschrecken
in Siidrussland,' 1866, p. 32, for I
have in vain endeavoured to procure
Korte's work.
29 Gilbert White, 'Nat. Hist, of
Selborne,' vol. ii. 1825, p. 262.
30 Harris, 'Insects of New Eng-
land,' 1842, p. 128.
, 3l 'The Naturalist on the Ama-
zons,' vol. i. 1863, p. 252. Mr.
Bates gives a very interesting dis-
cussion on the gradations in the
musical apparatus of the three
families. See also Westwood,
'Modern Class.' vol. ii. pp. 445
and 453.
32 ' Proc. Boston Soc. of Nat,
Hist.' vol. xi. April, 1868.
33 ' Nouveau Manuel d'Anat r
Comp.' fFrench translat.), torn, i
1850, p/567.
284 The Descent of Man. Part IL
In the three Families the sounds are differently produced. In
the males of the Achetidse both wing-covers have the same
apparatus; and this in the field-cricket (Gryllus campestris,
fig. 11) consists, as described by Landois, 34 of from 131 to 138
sharp, transverse ridges or teeth (st) on the under side of one of
the nervures of the wing-cover. This toothed nervure is rapidly
scraped across a projecting, smooth, hard ner-
vure (r) on the upper surface of the opposite
wing. First one wing is rubbed over the
other, and then the movement is reversed.
Both wings are raised a little at the same
time, so as to increase the resonance. In
some species the wing-covers of the males are
furnished at the base with a talc-like plate. 35
I here give a drawing (fig. 12) of the teeth on
the under side of the nervure of another
Fig. 12. Teeth of Ner- species of Gryllus, viz., 0. domesticus. With
Sr ( from U i^Dd o?sr respect to the formation of these teeth, Dr.
Gruber has shewn 36 that they have been de-
veloped by the aid of selection, from the minute scales and hairs
with which the wings and body are covered, and I came to the
same conclusion with respect to those of the Coleoptera. But
Dr. Gruber further shews that their- development is in part
directly due to the stimulus from the friction of one wing over
the other.
In the Locustidse the opposite wing-covers differ from each
other in structure (fig. 13), and the action cannot, as in the
last family, be reversed. The left wing, which acts as the
bow, lies over the right wing which serves as the fiddle. One
of the nervures (a) on the under surface of the former is
finely serrated, and is scraped across the prominent nervures
on the upper surface of the opposite or right wing. In our
British Phasgonura viridissima it appeared to me that the
serrated nervure is rubbed against the rounded hind-corner
of the opposite wing, the edge of which is thickened, coloured
brown, and very sharp. In the right wing, but not in the left,
there is a little plate, as transparent as talc, surrounded by
nervures, and called the speculum. In Ephippiger vitium, a
member of this same family, we have a curious subordinate
modification ; for the wing-covers are greatly reduced in size,
but " the posterior part of the pro-thorax is elevated into a kind
34 'Zeitschrift fiir wissenschaft. 36 'Ueber der Tonapparat der
Zoolog/ B. xvii. 1867, s. 117. Locustiden, em Beitrag zum Dar-
35 Westwood, * Modern Class, of winismus,' 'Zeitsch. fur wissensch.
Insects/ vol. i. p. 440. Zoolog.' B. xxii. 1872, p. 100.
Chap. X
Orthoptera.
285
'* of dome over the wing-covers, and which has probably the
" effect of increasing the sound." 37
Fig. 13. Chlorocoelus Tanana (from Bates), a, b. Lobes of opposite wing-covers.
We thus see that the musical apparatus is more differentiated
or specialised in the Locustidse (which include, I believe, the
most powerful performers in the Order), than in the Achetidse,
in which both wing-covers have the same structure and the
same function. 58 Landois, however, detected in one of the
Locustidse, namely in Decticus, a short and narrow row of small
teeth, mere rudiments, on the inferior surface of the right wing-
cover, which underlies the other and is never used as the bow,
I observed the same rudimentary structure on the under side of
the right wing-cover in Phasgonura viridissima. Hence we may
infer with confidence that the Locustidse are descended from a
form, in which, as in the existing Achetidse, both wing-covers
had serrated nervures on the under surface, and could be
/indifferently used as the bow; but that in the Locustidse the
two wing-covers gradually became differentiated and perfected*
37 Westwood, * Modern Class, of Insects,* vol. i. p. 453.
58 landois, * Zeitsch. f. wiss. Zoolog.' B. xvii. 1867, s. 121, 122,
286
The Descent of Man.
Paet IL
on the principle of the division of labour, the one to act ex-
clusively as the bow, and the other as the fiddle. Dr. Gruber
takes the same view, and has shewn that rudimentary teeth are
commonly found on the inferior surface of the right wing. By
what steps the more simple apparatus in the Achetidse originated,
we do not know, but it is probable that the basal portions of
the wing-covers originally overlapped each other as they do at
present; and that the friction of the nervures produced a
grating sound, as is now the case with the wing-covers of the
females. 39 A grating sound thus occasionally and accidentally
made by the males, if it served them ever so little as a love-call
to the females, might readily have been intensified through
sexual selection, by variations in the roughness of the nervures
having been continually preserved.
In the last and third Family, namely the AcridiidaB or
grasshoppers, the stridulation, is produced in a very different
manner, and according to Dr. Scudder, is not so shrill as in the
preceding Families. The inner surface of the femur (fig. 14, r)
is furnished with a longitudinal row of minute, elegant, lancet-
shaped, elastic teeth, from 85 to 93 in number ; 40 and these are
scraped across the sharp, projecting nervures on the wing-covers,
which are thus made to vibrate and resound. Harris 41 says
that when one of the males
begins to play, he first " bends
" the shank of the hind-leg
" beneath the thigh, where it
" is lodged in a furrow de-
" signed to receive it, and
" then draws the leg briskly
" up and down. He does not
fl play both fiddles together,
" but alternately, first upon
" one and then on the other."
In many species, the base
of the abdomen is hollowed
out into a great cavity which
is believed to act as a re-
sounding board. In Pneu-
mora (fig. 15), a S. African,
genus belonging to the same family, we meet with a new
Fig. 14. Hind-leg of Stenobothrus pratorum :
r, the stridulating ridge ; lower figure, the
teeth forming the ridge, much magnified
(from Landois).
39 Mr. Walsh also informs me
that he has noticed that the female
of the Platyphyllum concavum,
"when captured makes a feeble
"grating noise by shuffling her
" wing-covers together."
40 Landois, ibid. s. 113.
41 * Insects of New England,*
1842, p. 133.
Chap. X
Ofthopierfo
2%J
and remarkable modification; in the males a small notched
ridge projects obliquely from each side of the abdomen,
against which the hind femora are rubbed. 42 As the male is
furnished with wings (the female being wingless), it is re-
markable that the thighs are not rubbed in the usual manner
against the wing-covers ; but this may perhaps be accounted for
by the unusually small size of the hind-legs. I have not been
able to examine the inner surface of the thighs, which, judging
Fig. 15. Pneumora (from specimens in the British Museum). Upper figure, male
lower figure, female.
from analogy, would be finely serrated. The species of Pneumora
have been more profoundly modified for the sake of stridulation
than any other orthopterous insect; for in the male the whole
body has been converted into a musical instrument, being
42 -Westwood 4 ' Modern Classification,' vol. i. p. 462.
2 88 TJw Descent of Man. Past IL
distended with air, like a great pellucid bladder, so as to
increase the resonance. Mr. Trimen informs me that at the
Cape of Good Hope these insects make a wonderful noise
during the night.
In the three foregoing families, the females are almost always
destitute of an efficient musical apparatus. But there are a few
exceptions to this rule, for Dr. Gruber has shewn that both
sexes of Epkippiger vitium are thus provided; though the organs
differ in the male and female to a certain extent. Hence we
cannot suppose that they have been transferred from the male
to the female, as appears to have been the case with the secondary
sexual characters of many other animals. They must have been
independently developed in the two sexes, which no doubt
mutually call to each other during the season of love. In most
other Locustidse (but not according to Landois in Decticus) the
females have rudiments of the stridulatory organs proper to the
male; from whom it is probable that these have been transferred.
Landois also found such rudiments on the under surface of the
wing-covers of the female Achetidse, and on the femora of the
female Acridiidae. In the Homoptera, also, the females have the
proper musical apparatus in a functionless state ; and we shall
hereafter meet in other divisions of the animal kingdom with
many instances of structures proper to the male being present
in a rudimentary condition in the female.
Landois has observed another important fact, namely, that in
the females of the Acridiidae, the stridulating teeth on the
femora remain throughout life in the same condition in which
they first appear during the larval state in both sexes. In the
males, on the other hand, they become further developed, and
acquire their perfect structure at the last moult, when the insect
is mature and ready to breed.
From the facts now given, we see that the means by which
the males of the Orthoptera produce their sounds are extremely
diversified, and are altogether different from those employed by
the Homoptera. 43 But throughout the animal kingdom wo
often find the same object gained by the most diversified means ;
this seems due to the whole organisation having undergone mui- .
tifarious changes in the course of ages, and as part after part
varied different variations were taken advantage of for the
same general purpose. The diversity cf means for producing
sound in the three families of the Orthoptera and in the
** Landois has recently found in moptera ; and this is a surprising
c*rtam Orthoptera rudimentary fact. S<e 'Zeitschr. fiir wissensch.
structures closely similar to the Zoolcg.' B. xxii. Heft 3, 1871, jx
soird-prodtrcing organs in the Ho- 348.
Chap. X. Orthoptera. 28g
Homoptera, impresses the mind with the high importance ol these
structures to the males, for the sake of calling or alluring the
females. We need feel no surprise at the amount of modification
which the Orthoptera have undergone in this respect, as we now
Juiow, from Dr. Scudder's remarkable discovery, 44 that there has
Deen more than ample time. This naturalist has lately found
a fossil insect in the Devonian formation of New Brunswick,
which is furnished with " the well-known tympanum or stridu-
" lating apparatus of the male Locustidss." The insect, though
in most respects related to the Neuroptera, appears, as is so often
the case with very ancient forms, to connect the two related
Orders of the Neuroptera and Orthoptera.
I have but little more to say on the Orthoptera. Some of the
species are very pugnacious: when two male field-crickets
(Gryllus campestris) are confined together, they fight till one
kills the other; and the species of Mantis are described as
manoeuvring with their sword-like front-limbs, like hussars with
their sabres. The Chinese keep these insects in little bamboo
cages, and match them like game-cocks. 45 With respect to
colour, some exotic locusts are beautifully ornamented; the
posterior wings being marked with red, blue, and black; but as
throughout the Order the sexes rarely differ much in colour, it
is not probable that they owe their bright tints to sexual
selection. Conspicuous colours may be of use to these insects,
by giving notice that they are unpalatable. Thus it has been
observed 46 that a bright-coloured Indian locust was invariably
rejected when offered to birds and lizards. Some cases, however,
are known of sexual differences in colour in this Order. The
male of an American cricket 47 is described as being as white as
ivory, whilst the female varies from almost white to greenish-
yellow or dusky. Mr. Walsh informs me that the adult male of
Spectrum femoralum (one of the Phasmidse) " is of a shining
" brownish-yellow colour ; the adult female being of a dull,
" opaque, cinereous brown ; the young of both sexes being green."
Lastly, I may mention that the male of one curious kind of
cricket 4 * is furnished with "a long membranous appendage,
" which falls over the face like a veil ;" but what its usa may be,
is not known.
44 * Transact. Ent. Soc.' 3rd series, 47 The (Ecanthus nivalis. Harris,
vol. ii. (* Journal of Proceedings/ * Insects of New England/ 1842, p.
p. 117.) 124. The two sexes of (E. pellucldus
45 Westwood, 'Modern Class, of of Europe differ, as I hear from
Insects/ vol. i. p. 427 ; for crickets, Victor Cams, in nearly the same
p. 445. manner.
<6 Mr. Ch. Home, in ' Proc. Ent. 4B Platyblemnus : Westwood,
Soc.* May 3, 1869. p. xii. 'Modern Claes.' vol. i. p. 447.
290 Tke Descent of Man. Part j'JL
Order, Neuroptera. — Little need here be said, except as to
colour. In the EphemeridsB the sexes often differ slightly in
their obscure tints; 49 but it is not probable that the males are
thus rendered attractive to the females. The Libellulidae, or
dragon-flies, are ornamented with splendid green, blue, yellow,
and vermilion metallic tints ; and the sexes often differ. Thus,
as Prof. Westwood remarks, 50 the males of some of the
AgrionidaB, " are of a rich blue with black wings, whilst the
u females are fine green with colourless wings." But in Agrion
Ramhurii these colours are exactly reversed in the two sexes. 51
In the extensive N. American genus of Hetoina, the males alone
have a beautiful carmine spot at the base of each wing. In
Anax Junius the basal part of the abdomen in the male is a vivid
ultramarine blue, and in the female grass-green. In the allied
genus Gomphus, on the other hand, and in some other genera,
the sexes differ but little in colour. In closely-allied forms
throughout the animal kingdom, similar cases of the sexes
differing greatly, or very little, or not at all, are of frequent
occurrence. Although there is so wide a difference in colour
between the sexes of many Libellulidse, it is often difficult to say
which is the more brilliant ; and the ordinary coloration of the
two sexes is reversed, as we have just seen, in one species of
Agrion. It is not probable that their colours in any case have
been gained as a protection. Mr. MacLachlan, who has closely
attended to this family, writes to me that dragon-flies— the
tyrants of the insect- world — are the least liable of any insect to
be attacked by birds or other enemies, and he believes that their
bright colours serve as a sexual attraction. Certain dragon-flies
apparently are attracted by particular colours : Mr. Patterson
observed 52 that the AgrionidaB, of which the males are blue,
settled in numbers on the blue float of a fishing line ; whilst two
other specie* were attracted by shining white colours.
It is an interesting fact;, first noticed by Schelver, that, in
several genera belonging to two sub-families, the males on first
emergence from the pupal state, are coloured exactly like the
females; but that their bodies in a short time assume a con-
spicuous milky-blue tint, owing to the exudation of a kind of oil,
soluble in ether and alcohol. Mr. MacLachlan believes that in
the male of Libellula depressa this change of colour does not occur
until nearly a fortnight after the metamorphosis, when the sexes
are ready to pair.
*• B. D. Walsh, the * Pseudo-neu- indebted to thii naturalist for the
roptera of Illinois/ in * Proc. Ent. following facts on Hetaerina, Anax,
Soc of Philadelphia/ 1862, p. 361. and Gomphus.
** < Modern Class/ vol. ii. p. 37. ** 'Transact. Ent. Soc.' vol. k
** Walsh, ibid. p. 381. I am 1836, p. Ixxxi.
Chap. X Hyntenopterd. 291
Certain species of Neurothemis present, according to Brauer, 6S
ft curious case of dimorphism, some of the females having ordinary
wings, whilst others have them "very richly netted, as in the
** males of the same species." Brauer " explains the phenomenon
•' on Darwinian principles by the supposition that the close
" netting of the veins is a secondary sexual character in the
*' males, which has been abruptly transferred to some of the
" females, instead of, as generally occurs, to all of them." Mr.
MacLachlan informs me of another instance of dimorphism
in several species of Agrion, in which some individuals are of
an orange colour, and these are invariably females. This is
probably a case of reversion ; for in the true Libellulse, when
the sexes differ in colour, the females are orange or yellow ;
so that supposing Agrion to be descended from some primordial
form which resembled the typical Libellulse in its sexual cha-
racters, it would not be surprising that a tendency to vary in
this manner should occur in the females alone.
Although many dragon-flies are large, powerful, and fierce
insects, the males have not been observed by Mr. MacLachlan to
fight together, excepting, as he believes, in some of the smaller
species of Agrion. In another group in this Order, namely, the
Termites or white ants, both sexes at the time of swarming may
be seen running about, " the male after the female, sometimes
" two chasing one female, and contending with great eagerness
" who shall win the prize." 54 The Atropos pulsatorius is said
to make a noise with its jaws, which is answered by other
individuals. 66
Order, Hymenoptera. — That inimitable observer, M Fabre, 56 in
describing the habits of Cerceris, a wasp-like insect, remarks that
" fights frequently ensue between the males for the possession of
" some particular female, who sits an apparently unconcerned
" beholder of the struggle for supremacy, and when the victory
" is decided, quietly flies away in company with the conqueror,"
Westwood 67 says that the males of one of the saw-flies (Tenthre-
dinse) " have been found fighting together, with their mandibles
' locked." As M. Fabre speaks of the males of Cerceris striving
to obtain a particular female, it may be well to bear in mind
that insects belonging to this Order have the power of recognising
58 See abstract in the ' Zoological 56 See an interesting article^
Record' for 1867, p. 450. 'The Writings of Fabre,'' in 'Nat.
'** Kirby and Spence, 'Introduct. Hist. Review,' April 1862, p. 122.
to Entoirology,' vol. ii. 1818, p. 35. A7 'Journal of Proc. of Entorcolog
* y Kc£3eau, * Les Facultes Men- Soc.' Sept. 7th, 1863, p. 169.
JaW&c. Tom. i. p. 104.
d2
2g2 The Descent of Man, Paet 1L
each other after long intervals of time, and are deeply attached.
For instance, Pierre Huber, whose accuracy no one doubts,
separated some ants, and when, after an interval of four months,
they met others which had formerly belonged to the same
community, they recognised and caressed one another with their
antennae. Had they been strangers they would have fought
together. Again, when two communities engage in a battle, the
ants on the same side sometimes att&ck each other in the general
confusion, but they soon perceive their mistake, and the one ant
soothes the other. 58
In this Order slight differences m colour, according to sex, are
common, but conspicuous differences are rare except if the
family of Bees ; yet both sexes of certain groups are so brilliantly
coloured— for instance in Chrysis, in which vermilion and
metallic greens prevail — that we are tempted to attribute the
result to sexual selection. In the Ichneumonid®, according to
Mr. Walsh, 59 the males are almost universally lighter-coloured
than the females. On the other hand, in the Tenthredinidee the
males are generally darker than the females. In the Siricidra
the sexes frequently differ ; thus the male of Sirex juvencus is
banded with orange, whilst the female is dark purple ; but it is
difficult to say which sex is the more ornamented. In Tremex
eolumbee the female is much brighter-coloured than the male.
I am informed by Mr. F. Smith, that the male ants of several
species are black, the females being testaceous.
In the family of Bees, especially in the solitary species, as I
hear from the same entomologist, the sexes often differ in colour.
The males are generally the brighter, and in Bombus as well as in
Apathus, much more variable in colour than the females. In
Anthophora retusa the male is of a rich fulvous-brown, whilst
the female is quite black : so are the females of several species
of Xylocopa, the males being bright yellow. On the other hand
the females of some species, as of Andrcena fulva, are much
brighter-coloured than the males. Such differences in colour
can hardly be accounted for by the males being defenceless and
thus requiring protection, whilst the females are well defended
by their stings. H. Miiller, 60 who has particularly attended to
the habits of bees, attributes these differences in colour in chief
part to sexual selection. That bees have a keen percei>tion of
colour is certain. He says that the males search eagerly and
fight for the possession of the females ; and he accounts through
*" P. Huber, ' Recherches sur les Philadelphia,' 1866, pp. 23&-239.
Moeurs des Fourmis,' 1810, pp. 150, " * Anwendung der Darwinsckea
165. Lehre auf Bienen/ Vsrn. a. a,
* ' Proc. Entomolog. Soc. of JaLrg. xxix.
Chap.X Hymenoptera. 293
such contests for the mandibles of the males being in certain
species larger than those of the females. In some cases the
males are far more numerous than the females, either early
in the season, or at all times and places, or locally ; whereas the
females in other cases are apparently in excess. In some species
the more beautiful males appear to have been selected by the
females ; and in others the more beautiful females by the males.
Consequently in certain genera (Mtiller, p. 42), the males of the
several species differ much in appearance, whilst the females are
almost indistinguishable ; in other genera the reverse occurs.
H. Miiller believes (p. 82) that the colours gained by one sex
fiirough sexual selection have often been transferred in a variable
degree to the other sex, just as the pollen-collecting apparatus
of the female has often been transferred to the male, to whom
it is absolutely useless. 61
Mutilla .Europasa makes a stridulating noise ; and according to
Goureau 62 both sexes have this power. He attributes the sound
to the friction of the third and preceding abdominal segments,
and I find that these surfaces are marked with very fine con-
centric ridges ; but so is the projecting thoracic collar, into which
the head articulates, and this collar, when scratched with the
point of a needle, emits the proper sound. It is rather surprising
that both sexes should have the power of stridulating, as the
male is winged and the female wingless. It is notorious that
Bees express certain emotions, as of anger, by the tone of their
humming; and according to H. Miiller (p. 80), the males of
some species make a peculiar singing noise whilst pursuing the
females.
61 M. Perrier in his article * la Se- male grandfathers ? To take a case
lection sexuelle d'apres Darwin* (' Re- with ordinary animals as nearly
vue Scientifique/ Feb. 1873, p. 868), parallel as possible: if a female ol
without apparently having reflected any white quadruped or bird were
much on the subject, objects that as crossed by a male of a black breed,
the males of social bees are known and the male and female offspring
to be produced from unfertilised were paired together, will it be
ova, they could not transmit new pretended that the grandchildren
characters to their male offspring, would not inherit a tendency to
This is an extraordinary objection, blackness from their male grand-
A female bee fertilised by a male, father ? The acquirement of new
which presented some character fa- characters by the sterile worker-bees
cilitating the union of the sexes, or is a much more difficult case, but 1
rendering him more attractive to have endeavoured to show in my
the female, would lay eggs which * Origin of Species,' how these steril a
would produce only females ; but beings are subjected to the power ot
these young females would next natural selection,
year produce males , and will it be fl2 Quoted by Westwood, * Modern
pretended that such males would Class, of Insects/ vol. ii. p. 214
not inherit the characters of their
294 The Descent of Man. PaktK
Order, Coleoptera (Beetles). — Many beetles are coloured so as
to resemble the surfaces which they habitually frequent, and
they thus escape detection by their enemies. Other species, for
instance diamond-beetles, are ornamented with splendid colours,
which are often arranged in stripes, spots, crosses, and other
elegant patterns. Such colours can hardly serve directly as a
protection, except in the case of certain flower-feeding species ;
but they may serve as a warning or means of recognition, on the
same principle as the phosphorescence of the glow-worm. As
with beetles the colours of the two sexes are generally alike, we
have no evidence that they have been gained through sexual
selection; but this is at ]east possible, for they may have been
developed in one sex and then transferred to the other ; and
this view is even in some degree probable in those groups which
possess other well-marked secondary sexual characters. Blind
beetles, which cannot of course behold each other's beauty,
never, as I hear from Mr. Waterhouse, jun., exhibit bright
colours, though they often have polished coats ; but the expla-
nation of their obscurity may be that they generally inhabit
caves and other obscure stations.
Some Longicorns, especially certain Prionidse, offer an excep-
tion to the rule that the sexes of beetles do not differ in colour.
Most of these insects are large and splendidly coloured. The
males in the genus Pyrodes, 6a which I saw in Mr. Bates's col-
lection, are generally redder but rather duller than the females,
the latter being coloured of a more or less splendid golden-green.
On the other hand, in one species the male is golden-green, the
female being richly tinted with red and purple. In the genus
Esmeralda the sexes differ so greatly in colour that they have
been ranked as distinct species ; in one species both are of a
beautiful shining green, but the male has a red thorax. On the
whole, as far as I could judge, the females of those Prionidsa, in
63 Pyrodes pulcherrimus, in the family of Longicorns. Messrs
which the sexes differ conspicuously, R. Trimen and Waterhouse, jun.,
has been described by Mr. Bates in inform me of two Lamellicorns,
' Transact. Ent. Soc* 1869, p. 50. viz., a Peritrichia and Trichius, the
I will specify the few other cases in male of the latter being more
which I have heard of a difference obscurely coloured than the female,
in colour between the sexes of In Tillus elongatus the male is black,
beetle*. Kirby and Spence ('In- and the female always, as it is
troduct. to Entomology,' vol. iii. p. believed, of a dark blue colour, with
301) mention a Cantharis, Meloe, a red thorax. The male, also, of
Rhagium, and the Leptura testacea ; Orsodacna atra, as I hear from Mr.
the male of the latter being tes- Walsh, is black, the female (tht
taceous, with a black thorax, and so-called 0. ruficollis) having a
the female of a dull red all ovei. ^ifous thorax.
These two latter beetles belong to
Chap. X.
Coleoptera.
295
which the sexes differ, are coloured more richly than the males,
and this does not accord with the common rule in regard to
colour, when acquired through sexual selection.
A most remarkable distinction between the sexes of many-
beetles is presented by the great horns which rise from the head,
thorax, and clypeus of the males; and in some few cases from
the under surface of the body. These horns, in the great family
of the Lamellicorns, resemble. those of various quadrupeds, such
as stags, rhinoceroses, &c, and are wonderful both from their
size and diversified shapes. Instead of describing them, I have
given figures of the males and females of some of the more re-
markable forms. (Figs. 16 to 20.) The females generally ex-
hibit rudiments of the horns in the form of small knobs or
ridges ; but some are destitute of even the slightest rudiment.
On the other hand, the horns are nearly as well developed in the
female as in the male of Phanceus lancifer ; and only a little less
well developed in the females of some other species of this genus
and of Copris, I am informed by Mr. Bates that the horns do
not differ in any manner corresponding with the more important
characteristic differences between the several subdivisions of the
family : thus within the same section of the genus Onthophagus,
there are species which have a single horn, and others which
have two.
^Fig, 16. CMoosoma atlas.
Upper figure, male (reduced) ; lower figure, female
(nat.size).
2Q6 The Descent of Man. Part II
Copris isidis. (Left-hand figures, males.)
Fig. 18.
Phanasus faunus.
Dipelicus cantori.
Fig* 20. Onthophacrns rangifer. enlarged.
Chap. X Coleoptera. 297
In almost all cases, the horns are remarkable from their ex-
cessive variability ; so that a graduated series can be formed,
from the most highly developed males to others so degenerate
that they can barely be distinguished from the females. Mr.
Walsh 64 found that in Phanceus carnifea, the horns were thrice as
long in some males as in others. Mr. Bates, after examining
above a hundred males of Onthophagm rangifer (fig. 20), thought
that he had at last discovered a species in which the horns did
not vary ; but further research proved the contrary.
The extraordinary size of the horns, and their widely different
structure in closely-allied forms, indicate that they have been
formed for some purpose ; but their excessive variability in the
males of the same species leads to the inference that this purpose
cannot be of a definite nature. The horns do not show marks of
friction, as if used for any ordinary work. Some authors sup-
pose 65 that as the males wander about much more than the
females, they require horns as a defence against their enemies;
but as the horns are often blunt, they do not seem well adapted
for defence. The most obvious conjecture is that they are used
by the males for fighting together; but the males have never
been observed to fight; nor could Mr. Bates, after a careful
examination of numerous species, find any sufficient evidence, in
their mutilated or broken condition, of their having been thus
used. If the males had been habitual fighters, the size of their
bodies would probably have been increased through sexual
selection, so as to have exceeded that of the females; but
Mr. Bates, after comparing the two sexes in above a hundred
species of the CopridaB, did not find any marked difference in
this respect amongst well-developed individuals. In Lethrus,
moreover, a beetle belonging to the same great division of the
Lamellicorns, the males are known to fight, but are not provided
with horns, though their mandibles are much larger than those
of the female.
The conclusion that the horns have been acquired as ornaments
is that which best agrees with the fact of their having been so
immensely, yet not fixedly, developed, — as shewn by their extreme
variability in the same species, and by their extreme diversity in
closely-allied species. This view will at first appear extremely
improbable; but we shall hereafter find with many animals
standing much higher in the scale, namely fishes, amphibians,
reptiles and birds, that various kinds of crests, knobs, horns and
combs have been developed apparently for this sole purpose.
The males of Onitis furcifer (fig. 21), and of some other
** ' Proc. Entomolog. Soc. of •* Kirby and Spence, ' Introduce
Philadelphia, 1864, p. 228 Entomolog.' vol. iii. p. 300*
S9»
The Descent of Man,
Part II.
species of the genus, are furnished with singular projections on
their anterior femora, and with a great fork or pair of horns on
the lower surface of the thorax. Judging
from other insects, these may aid the male
in clinging to the female. Although the
males have not even a trace of a horn on
the upper surface of the body, yet the fe-
males plainly exhibit a rudiment of a single
horn on the head (fig. 22, a), and of a crest
(b) on the thorax. That the slight thoracic
«£ V > S cres * * n ^ e ^ ema ^ e * s a rudiment of a pro-
T* * ' jection proper to the male, though entirely
absent in the male of this particular species,
is clear : for the female of Bubas bison (a
genus which comes next to Onitis) has a
similar slight crest on the thorax, and the male bears a great
projection in the same situation. So, again, there can hardly be
a doubt that the little point (a) on the head of the female Onitis
Fig 21. Onitis furcifer,
male viewed from be-
neath.
Fig. 22. Left-hand figure, male of Onitis furcifer, viewed laterally. Right-hand
figure, female, a. Rudiment of cephalic horn. b. Trace of thoracic horn or crest.
furcifer, as well as on the head of the females of two or three
allied species, is a rudimentary representative of the cephalic
horn, which is common to the males of so many Lamellicorn
beetles, as in Phanseus (fig. 18).
The old belief that rudiments have been created to complete
the scheme of nature is here so far from holding good, that we
have a complete inversion of the ordinary state of things in the
family. We may reasonably suspect that the males originally
bore horns and transferred them tc the females in a rudimentary
condition, as in so many other Lamellicorns. Why the males
subsequently lost their horns, we know not ; but this may have
been caused through the principle of compensation, owing to
the development of the large horns and projections on the lower
surface ; and as these are confined to the males, the rudiments
of the upper horns on the females would not have been thus
obliterated.
Chap. X. Coleoptera. 299
The cases hitherto given refer to the Lamellicorns, but the
males of some few other beetles, belonging to two widely distinct
groups, namely, the Curculionidae and StaphylinidaB, are fur-
nished with horns — in the former on the lower surface of the
body, 66 in the latter on the upper surface of the head and thorax.
In the Staphylinidae, the horns of the males are extraordinarily
variable in the same species, just as we have seen with the
Lamellicorns. In Siagonium we have a case of dimorphism,
for the males can be divided into two sets, differing greatly
in the size of their bodies and in the development of their
horns, without intermediate gradations. In a species of Bledius
(fig. 23), also belonging to the Staphylinidse, Professor Westwood
Fig. 23. Bledius taurus, magnified. Left-hand figure, male ; right-handjgure female
states that, " male specimens can be found in the same locality
" in which the central horn of the thorax is very large, but the
" horns of the head quite rudimental; and others, in which the
"thoracic horn is much shorter, whilst the protuberances on
" the head are long/' 67 Here we apparently have a case of
compensation, which throws light on that just given of the
supposed loss of the upper horns by the males of Onitis.
Law of Battle, — Some male beetles, which seem ill-fitted for
fighting, nevertheless engage in conflicts for the possession of
the females. Mr. Wallace 68 saw two males of Leptorhynchus
angustatus, a linear beetle with a much elongated rostrum,
"' fighting for a female, who stood close by busy at her boring.
* They pushed at each other with their rostra, and clawed and
" thumped, apparently in the greatest rage." The smaller male,
however, "soon ran away, acknowledging himself vanquished."
In some few cases male beetles are well adapted for fighting, by
possessing great toothed mandibles, much larger than those of
the females. This is the case with the common stag-beetlo
(Lucanus cervus), the males of which emerge from the pupal
state about a week before the other sex, so that several may
often be seen pursuing the same female. At this season they
66 Kirby and Spence, 'Introduct. gonium in an intermediate condi-
Entomolog.' vol. ill. p. 329. tion, so that the dimorphism is not
67 * Modern Classification of In- strict.
sects,' vol. i. p. 172: Siagonium, *>* 'The Malay Archipelago/ vol.
p. 172. In the British Museum I ii. 1869, p. 276. Riley, Sixth < Report
noticed one male specimen of §ia* on insects of Missouri/ 1874-,p. 114
300 The Descent of Man. Pabt H,
engage in fierce conflicts. When Mr. A. H. Davis ^ enclosed
two males with one female in a box, the larger male severely
pinched the smaller one, until he resigned his pretensions. A
friend informs me that when a boy he often put the males
together to see them fight, and he noticed that they were much
bolder and fiercer than the females, as with the higher animals.
The males would seize hold of his finger, if held in front of
them, but not so the females, although they have stronger
jaws. The males of many of the Lucanidse, as well as of the
above-mentioned Leptorhynchus, are larger and more powerful
insects than the females. The two sexes of Lethrus cephalotes
(one of the Lamellicorns) inhabit the same burrow; and the
male has larger mandibles than the female. If, during the
breeding-season, a strange male attempts to enter the burrow,
he is attacked ; the female does not remain passive, but closes
the mouth of the burrow, and encourages her mate by con-
tinually pushing him on from behind ; and the battle lasts until
the aggressor is killed or runs away. 70 The two sexes of another
Lamellicorn beetle, the Ateuchus cicatricosus, live in pairs, and
seem much attached to each other ; the male excites the female
to roll the balls of dung in which the ova are deposited ; and if
she is removed, he becomes much agitated. If the male is
removed the female ceases all work, and as M. Brulerie 71 believes,
would remain on the same spot until she died.
The great mandibles of the male LucanidaB are extremely
variable both in size and structure, and in this respect resemble
the horns on the head and thorax of many male Lamellicorns
and Staphylinidse. A perfect series can be formed from the
best-provided to the worst-provided or degenerate males. Al-
though the mandibles of the common stag-beetle, and probably
of many other species, are used as eflicient weapons for fighting,
it is doubtful whether their great size can thus be accounted
for. We have seen that they are used by the Lucanus elcvphus
of N. America for seizing the female. As they are so con-
spicuous and so elegantly branched, and as owing to their great
length they are not well adapted for pinching, the suspicion
has crossed my mind that they may in addition serve as an
ornament, like the horns on the head and thorax of the various
species above described. The male Cktasognathus Grantii of
S. Chile — a splendid beetle belonging to the same family — has
69 'Entomological Magazine,' vol. 70 Quoted from Fischer, in 'Diet,
i. 1833, p. 82. See also on the Class. d'Hist. Nat.' torn. x. p. 324.
conflicts of this species, Kirby and u ' Ann. Soc. Entomolog. France,
Spence, ibid. vol. iii. p. 314; and 1866, as quoted in 'Journal of
Westwood, ibid. vol. i. p. 187. Travel,' by A. Murray, 1968, p. 105,
Chap. X.
Coleoptera.
30X
enormously developed mandibles (fig. 24) ; he is bold and pug-
nacious ; when threatened he faces round, opens his great jaws,
and at the same time stridulates loudly.
But the mandibles were not strong
enough to pinch my finger so as to
cause actual pain.
Sexual selection, which implies the
possession of considerable perceptive
powers and of strong passions, seems
to have been more effective with the
Lamellicorns than with any other
family of beetles. "With some species
the males are provided with weapons
for fighting; some live in pairs and
show mutual affection; many have
the power of stridulating when excited ;
many are furnished with the most ex-
traordinary horns, apparently for the
sake of ornament ; and some, which
are diurnal in their habits, are gor-
geously coloured. Lastly, several of
the largest beetles in the world belong
to this family, which was placed by
LinnsBus and Fabricius at the head of
the Order. 72
Stridulating organs. — Beetles belong-
ing to many and widely distinct
families possess these organs. The
sound thus produced can sometimes
be heard at the distance of several feet
or even yards, 73 but it is not comparable
with that made by the Orthoptera.
The rasp generally consists of a narrow,
slightly-raised surface, crossed by very
fine, parallel ribs, sometimes so fine as
to cause iridescent colours, and having
a very elegant appearance under the
microscope. In some cases, as with
Typhosus, minute, bristly or scale-like
prominences, with which the whole
surrounding surface is covered in approximately parallel
lines, could be traced passing into the ribs of the rasp. The
Fier. 24. Chiasognathus grantii,
reduced. Upper figure, male 5
lower figure, female.
72 Westwood, 'Modern Class/
rol. i. p. 184.
n Wollaston, ' On certain Musical
Curculionidae,' ' Annals and Mag. o\
Nat. Hist.' vol. vi. 1860, p. 14.
302
The Descent of Man.
PartH.
transition takes place by their becoming confluent and straight,
and at the same time more prominent and smooth. A hard
ridge on an adjoining part of the body serves as the scrape*
for the rasp, but this scraper in some cases has been specially
modified for the purpose. It is rapidly moved across the rasp,
or conversely the rasp across the scraper.
Fig. 25. Necrophorus (from Landois). r. The two rasps. Left-hand figure, part of
the rasp highly magnified.
These organs are situated in widely different positions. In
the carrion-beetles (Necrophorus) two parallel rasps (r, fig. 25)
stand on the dorsal surface of the fifth abdominal segment, each
rasp 74 consisting of 126 to 140 fine ribs. These ribs are scraped
against the posterior margins of the elytra, a small portion of
which projects beyond the general outline. In many Crioceridse,
and in Clyikra punctata (one of the Chrysomelidae), and in some
Tenebrionidse, &c., 75 the rasp is seated on the dorsal apex of the
abdomen, on the pygidium or pro-pygidium, and is scraped in
the same manner by the elytra. In Heterocerus, which belongs
to another family, the rasps are placed on the sides of the
first abdominal segment, and are scraped by ridges on the
femora. 76 In certain Curculionidss and Carabidse, 77 the parts
74 Landois, 'Zeitschrift fur wiss.
Zoolog.' B. xvii. 1867, s. 127.
75 I am greatly indebted to Mr.
G. R. Crotch for having sent me
many prepared specimens of various
beetles belonging to these three
families and to others, as well as for
valuable information. He believes
that the power of stridulation in
the Clythra has not been previously
observed. I am also much indebted
to Mr. E. W. Janson, for informa-
tion and specimens. I may add
that my son, Mr. F. Darwin, finds
that Dermestes murinus stridulates,
but he searched in vain for the
apparatus. Scolyius has lately
been described by Dr. Chapman as
a stridulator, in the 'Entomolo-
gist's Monthly Magazine,' vol. vi. p.
130.
76 Schiodte, translated in ' Annals
and Mag. of Nat. Hist.' vol. xx.
1867, p. 37.
77 Westring has described (Kroyer,
* Naturhist. Tidskrift/ B. ii. 1848-
49, p. 334) the stridulating organs
in these two, as well as in other
families. In the Carabidse I have
examined Elaphrus uliginosus and
Blethisa multipwnctata, sent to me
by Mr. Crotch. In Blethisa the
transverse ridges on the furrowed
border of the abdominal segment da
Chap. X.
Coleoptera.
303
are completely reversed in position, for the rasps are seated on
the inferior surface of the elytra, near their apices, or along
their outer margins, and the edges of the abdominal segments
serve as the scrapers. In PeloUus Hermanni (one of Dytiscidas
or water-beetles) a strong ridge runs parallel and near to the
sutural margin of the elytra, and is crossed by ribs, coarse in
the middle part, but becoming gradually finer at both ends,
especially at the upper end; when this insect is held under
water or in the air, a stridulating noise is produced by the
extreme horny margin of the abdomen being scraped against
the rasps. In a great number of long-horned beetles (Longi-
cornia) the organs are situated quite otherwise, the rasp being
on the meso-thorax, which is rubbed against the pro-thorax;
Landois counted 238 very fine ribs on the rasp of Ceramhyx
heros.
Many Lamellicorns have the power of stridulating, and the
organs differ greatly in position. Some species stridulate very
loudly, so that when Mr. F. Smith caught a Trox sabuhsus, a
gamekeeper, who stood by, thought he had caught a mouse ;
but I failed to discover the proper organs in
this beetle. In Geotrupes and Typhosus a
narrow ridge runs obliquely across (r, fig. 26)
the coxa of each hind-leg (having in G. ster-
corals 84 ribs), which is scraped by a
specially projecting part of one of the ab-
dominal segments. In the nearly allied Copris
7unarzs, an excessively narrow fine rasp runs
along the sutural margin of the elytra, with
another short rasp near the basal outer mar-
gin; but in some other Coprini the rasp is
seated, according to Leconte, 78 on the dorsal
surface of the abdomen. In Oryctes it is
seated on the pro-pygidium ; and, according to
the same entomologist, in some other Dynastini,
on the under surface of the elytra. Lastly,
Westring states that in Omaloplia hrunnea the
rasp is placed on the pro-sternum, and the
scraper on the meta-sternum, the parts thus
occupying the under surface of the body, instead of the upper
surface as in the Longicorns.
We thus see that in the different coleopterous families the
Fig. 26. Hind-leg of
Geotrupes stercora-
rius (from Landois).
r. Rasp. c. Coxa. /.
Femur, t. Tibia
tr. Tarsi.
not, as far as I could judge, come
into play in scraping the rasps on
the elytra.
■ '" 1 ana indebted to Mr. Walsh,
of Illinois, for having sent me ex-
tracts from Leconte V Introduction
to Entomology,' pp. 101, 143.
304 Ttie Descent of Man. Part XL
etridulating organs are wonderfully diversified in position, but
not much in structure. Within the same family some species
are provided with these organs, and others are destitute of them.
This diversity is intelligible, if we suppose that originally various
beetles made a shuffling or hissing noise by the rubbing together
of any hard and rough parts of their bodies, which happened to
be in contact ; and that from the noise thus produced being in
some way useful, the rough surfaces were gradually developed
into regular stridulating organs. Some beetles as they move,
now produce, either intentionally or unintentionally, a shuffling
n/ise, without possessing any proper organs for the purpose.
Mr. Wallace informs me that the Euchirus longimanus (a
Lamellicorn, with the anterior legs wonderfully elongated in the
male) " makes, whilst moving, a low hissing sound by the pro-
" trusion and contraction of the abdomen ; and when seized it
" produces a grating sound by rubbing its hind-legs against the
" edges of the elytra." The hissing sound is clearly due to a
narrow rasp running along the sutural margin of each elytron ;
and I could likewise make the grating sound by rubbing the
shagreened surface of the femur against the granulated margin
of the corresponding elytron ; but I could not here detect any
proper rasp ; nor is it likely that I could have overlooked it in
so large an insect After examining Cychrus, and reading what
Westring has written about this beetle, it seems very doubtful
whether it possesses any true rasp, though it has the power of
emitting a sound.
From the analogy of the Orthoptera and Homoptera, I
expected to find the stridulating organs in the Coleoptera
differing according to sex; but Landois, who has carefully
examined several species, observed no such difference ; nor did
Westring; nor did Mr. G. E. Crotch in preparing the many
specimens which he had the kindness to send me. Any difference
in these organs, if slight, would, however, be difficult to detect,
on account of their great variability. Thus, in the first pair of
specimens of Necrophorus humator and of Pelobius which I ex-
amined, the rasp was considerably larger in the male than in
the female; but not so with succeeding specimens. In Geo-
trupes stercorarim the rasp appeared to me thicker, opaquer,
and more prominent in three males than in the same number of
females; in order, therefore, to discover whether the sexes
differed in their power of stridulating, my son, Mr. F. Darwin,
collected fifty-seven living specimens, which he separated into two
lots, according as they made a greater or lesser noise, when held
in the same manner. He then examined all these specimens,
and found that the males were very nearly in the same proportion
Chap. X. Coleoptera. 305
to the females in both the lots. Mr. F. Smith has kept alive
numerous specimens of Monoynchus pseudacoH (Gurculionidse),
and is convinced that both sexes stridulate, and apparently in
an equal degree.
Nevertheless, the power of stridulating is certainly a sexual
character in some few Coleoptera. Mr. Crotch discovered that
the males alone of two species of Heliopathes (Tenebrionicke)
possess stridulating organs. I examined live males of H. gibbus,
and in all these there was a well-developed rasp, partially
divided into two, on the dorsal surface of the terminal abdominal
segment ; whilst in the same number of females there was not
even a rudiment of the rasp, the membrane of this segment
being transparent, and much thinner than in the male. In
H. cribratostriatus the male has a similar rasp, excepting that it
is not partially divided into two portions, and the female is
completely destitute of this organ ; the male in addition has on
the apical margins of the elytra, on each side of the suture,
three or four short longitudinal ridges, which are crossed by
extremely fine ribs, parallel to and resembling those on the
abdominal rasp ; whether these ridges serve as an independent
rasp, or as a scraper for the abdominal rasp, I could not decide :
the female exhibits no trace of this latter structure.
Again, in three species of the Lamellicorn genus Oryctes, we
have a nearly parallel case. In the females of 0. gryphus and
nasicornis the ribs on the rasp of the pro-pygidium are less
continuous and less distinct than in the males; but the chief
difference is that the whole upper surface of this segment, when
held in the proper light, is seen to be clothed with hairs, which
are absent or are represented by excessively fine down in the
males. It should be noticed that in all Coleoptera the effective
part of the rasp is destitute of hairs. In 0. senegalensis the
difference between the sexes is more strongly marked, and this
is best seen when the proper abdominal segment is cleaned and
viewed as a transparent object. In the female the whole surface
is covered with little separate crests, bearing spines ; whilst in
the male these crests in proceeding towards the apex, become
more and more confluent, regular, and naked ; so that three-
fourths of the segment is covered with extremely fine parallel
ribs, which are quite absent in the female. In the females,
however, of all three species of Oryctes, a slight grating or
stridulating sound is produced, when the abdomen of a softened
specimen is pushed backwards and forwards.
In the case of the Heliopathes and Oryctes there can hardly
be a doubt that the males stridulate in order to call or to
excite the females; but with most beetles the stridulation
306 The Descent of Man. Part II.
apparently serves both sexes as a mutual call. Beetles stridu-
late under various emotions, in the same manner as birds use
their voices for many purposes besides singing to their mates.
*fhe great Chiasognathus stridulates in anger or defiance ; many
species do the same from distress or fear, if held so that they
cannot escape; by striking the hollow stems of trees in the
Canary Islands, Messrs. Wollaston and Crotch were able to
discover the presence of beetles belonging to the genus Acalles
by their stridulation. Lastly, the male Ateuchus stridulates to
encourage the female in her work, and from distress when she
is removed. 79 Some naturalists believe that beetles make this
noise to frighten away their enemies ; but I cannot think that
a quadruped or bird, able to devour a large beetle, would
be frightened by so slight a sound. The belief that the stridu-
lation serves as a sexual call is supported by the fact that death-
ticks (Anobium tessellation) are well known to answer each
other's ticking, and, as I have myself observed, a tapping noise
artificially made. Mr. Doubleday also informs me that he
has sometimes observed a female ticking, 80 and in an hour or
two afterwards has found her united with a male, and on one
occasion surrounded by several males. Finally, it is probable
that the two sexes of many kinds of beetles were at first
enabled to find each other by the slight shuffling noise produced
by the rubbing together of the adjoining hard parts of their
bodies; and that as those males or females which made the
greatest noise succeeded best in finding partners, rugosities on
various parts of their bodies were gradually developed by means
of sexual selection into true stridulating organs.
79 M. P. de la Brulerie, as quoted Landois, * Zeitschrift f iir wissen.
in * Journal of Travel,' A. Murray, Zoolog.' B. xvii. s. 131. Oliver
vol. i. 1868, p. 135. says (as quoted by Kirby and
80 According to Mr. Doubleday, Spence, 4 Introduct.' vol. ii. p. 395)
" the noise is produced by the in- that the female of Pimelia striata
" sect raising itself on its legs as produce* a rather loud sound by
" high as it can, and then striking striking her abdomen against any
** its thorax five or six times, in hard substance, " and that the male,
** rapid succession, against the sub- " obedient to this call, sow attend*
** stance upon which it is sitting." " her, *tid they pair."
For references on this subiect see
Chap. XI. Butterflies and Moths. 307
CHAPTER XL
Insects, continued, — Order Lepidopteba.
(butterflies and moths.)
Courtship of butterflies— Battles — Ticking noise — Colours common to
both sexes, or more brilliant in the males — Examples — Not due to the
direct action of the conditions of life — Colours adapted for protection —
Colours of moths — Display — Perceptive powers of the Lepidoptera—
Variability — Causes of the difference in colour between the males and
females — Mimicry, female butterflies more brilliantly coloured than
the males — Bright colours of caterpillars — Summary and concluding
remarks on the secondary sexual characters of insects — Birds and insects
compared.
In this great Order the most interesting points for us are the
differences in colour between the sexes of the same species, and
between the distinct species of the same genus. Nearly the
whole of the following chapter will be devoted to this subject ;
but I will first make a few remarks on one or two other points.
Several males may often be seen pursuing and crowding round
the same female. Their courtship appears to be a prolonged
affair, for I have frequently watched one or more males pirouet-
ting round a female until I was tired, without seeing the
end of the courtship. Mr. A. G. Butler also informs me that
he has several times watched a male courting a female for a full
quarter of an hour ; but she pertinaciously refused him, and at
last settled on the ground and closed her wings, so as to escape
from his addresses.
Although butterflies are weak and fragile creatures, they are
pugnacious, and an Emperor butterfly * has been captured with
the tips of its wings broken from a conflict with another male.
Mr. Collingwood, in speaking of the frequent battles between the
butterflies of Borneo, says, " They whirl round each other with
" the greatest rapidity, and appear to be incited by the greatest
" ferocity."
The Ageronia feronia makes a noise like that produced by a
toothed wheel passing under a spring catch, and which can be
heard at the distance of several yards : I noticed this sound at
Kio de Janeiro, only when two of these butterflies were chasing
each other in an irregular course, so that it is probably made
during the courtship of the sexes. 2
1 Apatura Iris : ' The Entomolo- Naturalist,' 1868, p. 183.
gtst's Weekly Intelligence/ 1859, p. 2 See my ' Journal of Researches,
139. For the Bornaan Butterflies, 1845, p. 33, Mr. Doubleday has
fee C. Collingwood, 'Rambles of a detected (' Proc. Ent. Soc/ March
x 2
308 The Descent of Man. Paet IL
Some moths also produce sounds ; for instance, the males of
Thecophora fovea. On two occasions Mr. F. Buchanan White 8
heard a sharp quick noise made by the male of Hylophila
prasinana, and which he believes to be produced, as in Cicada,
by an elastic membrane, furnished with a muscle. He quotes,
also, Guenee, that Setina produces a sound like the ticking
of a watch, apparently by the aid of " two large tympaniform
" vesicles, situated in the pectoral region;" and these "are much
" more developed in the male than in the female/' Hence the
sound-producing organs in the Lepidoptera appear to stand in
some relation with the sexual functions. I have not alluded
to the well-known noise made by the Death's Head Sphinx, for
it is generally heard soon after the moth has emerged from
its cocoon.
Girard has always observed that the musky odour, which is
emitted by two species of Sphinx moths, is peculiar to the males ; 4
and in the higher classes we shall meet with many instances of
the males alone being odoriferous.
Every one must have admired the extreme beauty of many
butterflies and of some moths ; and it may be asked, are their
colours and diversified patterns the result of the direct action of
the physical conditions to which these insects have been exposed,
without any benefit being thus derived ? Or have successive
variations been accumulated and determined as a protection,
or for some unknown purpose, or that one sex may be at-
tractive to the other ? And, again, what is the meaning of the
colours being widely different in the males and females of
certain species, and alike in the two sexes of other species of the
same genus ? Before attempting to answer these questions a
body of facts must be given.
With our beautiful English butterflies, the admiral, peacock,
and painted lady (VanesssB), as well as many others, the sexes
are alike. This is also the case with the magnificent Heliconidse,
and most of the Danaidse in the tropics. But in certain other
tropical groups, and in some of our English butterflies, as the
purple emperor, orange-tip, &c. (Apatwra Iris and Anthocharis
cardamines), the sexes differ either greatly or slightly in colour.
No language suffices to describe the splendour of the males of
3rd, 1845, p. 123) a peculiar mem- observations, * The Scottish Natural
branous sac at the base of the ist/ July 1872, p. 214.
front wings, which is probably con- 3 * The Scottish Naturalist/ Jul}
nected with the production of the 1872, p. 213.
sound. For the case of Thecophora, 4 * Zoological Record,' 1869, p,
roe ' Zoological Record,' 1869, p. 347,
401. Foi Mr. Buchanan Wh^'s
CfcAK XL Butterflies ana Moths. 309
some tropical species. Even within the same genus we often
find species presenting extraordinary differences between the
sexes, whilst others have their sexes closely alike. Thus in the
South American genus Epicalia, Mr. Bates, to whom I am
indebted for most of the following facts, and for looking over
this whole discussion, informs me that he knows twelve species,
the two sexes of which haunt the same stations (and this is not
always the case with butterflies), and which, therefore, cannot
have been differently affected by external conditions. 5 In nine of
these twelve species the males rank amongst the most brilliant of
all butterflies, and differ so greatly from the comparatively plain
females that they were formerly placed in distinct genera. The
females of these nine species resemble each other in their general
type of coloration; and they likewise resemble both sexes of
the species in several allied genera, found in various parts of
the world. Hence we may infer that these nine species, and
probably all the others of the genus, are descended from an
ancestral form which was coloured in nearly the same manner.
In the tenth species the female still retains the same general
colouring, but the male resembles her, so that he is coloured in
a much less gaudy and contrasted manner than the males of the
previous species. In the eleventh and twelfth species, the
females depart from the usual type, for they are gaily decorated
almost like the males, but in a somewhat less degree. Hence in
these two latter species the bright colours of the males seem to
have been transferred to the females ; whilst in the tenth
species the male has either retained or recovered the plain
colours of the female, as well as of the parent-form of the genus.
The sexes in these three cases have thus been rendered nearly
alike, though in an opposite manner. In the allied genus Eubagis,
both sexes of sonne of the species are plain-coloured and nearly
alike ; whilst with the greater number the males are decorated
with beautiful metallic tints in a diversified manner, and differ
much from their females. The females throughout the genus
retain the same general style of colouring, so that they resemble
one another much more closely than they resemble their own
males.
In the genus Papilio, all the species of the iEneas group
are remarkable for their conspicuous and strongly contrasted
colours, and they illustrate the frequent tendency to gradation
in the amount of difference between the sexes. In a few species,
for instance in P. ascanius, the males and females are alike; in
* See also Mr. Bates's paper in the same subject, in regard *o
* Proc. Ent. Soc. of Philadelphia,* Diadema, in * Transact. Entomolog,
1805, p. 206. Also Mr. Wallace on Soc. of London/ 1869, p. 278.
3 IO The Descent of Man. Part W
others the males are either a little brighter, or very much more
superb than the females. The genus Junonia, allied to our
Vanessae, offers a nearly parallel case, for although the sexes of
most of the species resemble each other, and are destitute of
rich colours, yet in certain species, as in J, cenone, the male is
rather more bright-coloured than the female, and in a few (for
instance J. andremiaja) the male is so different from the female
that he might be mistaken for an entirely distinct species.
Another striking case was pointed out to me in the British
Museum by Mr. A. Butler, namely, one of the tropical American
Theclse, in which both sexes are nearly alike and wonderfully
splendid ; in another species the male is coloured in a similarly
gorgeous manner, whilst the whole upper surface of the
female is of a dull uniform brown. Our common little English
blue butterflies of the genus Lycsena, illustrate the various dif-
ferences in colour between the sexes, almost as well, though not
in so striking a maimer, as the above exotic genera. In Lycxna
agestis both sexes have wings of a brown colour, bordered with
small ocellated orange spots, and are thus alike. In L. cegon
the wings of the male are of a fine blue, bordered with black
whilst those of the female are brown, with a similar border,
closely resembling the wings of L. agestis. Lastly, in L. avion both
sexes are of a blue colour and are very like, though in the female
the edges of the wings are rather duskier, with the black spots
plainer ; and in a bright blue Indian species both sexes are still
more alike.
I have given the foregoing details in order to show, in the first
place, that when the sexes of butterflies differ, the male as a
general rule is the more beautiful, and departs more from the
usual type of colouring of the group to which the species
belongs. Hence in most groups the females of the several
species resemble each other much more closely than do the
males. In some cases, however, to which I shall hereafter
allude, the females are coloured more splendidly than the
males. In the second place, these details have been given to
bring clearly before the mind that within the same genus, the
two sexes frequently present every gradation from no difference
in colour, to so great a difference that it was long before the two
were placed by entomologists in the same genus. In the third
place, we have seen that when the sexes nearly resemble each
other, this appears due either to the male having transferred
his colours to the female, or to the male having retained, or
perhaps recovered, the primordial colours of the group. It alsc
deserves notice that in those groups in which the sexes differ,
the females usually somewhat resemble the males, so that when
GtiAp. XL Butterflies and Moths. 311
the males are beautiful to an extraordinary degree, the females
almost invariably exhibit some degree of beauty. From the
many cases of gradation in the amount of difference between
the sexes, and from the prevalence of the same general type of
coloration throughout the whole of the same group, we may con-
clude that the causes have generally been the same which have
determined the brilliant colouring of the males alone of some
species, and of both sexes of other species.
As so many gorgeous butterflies inhabit the tropics, it has
often been supposed that they owe their colours to the great
heat and moisture of these zones ; but Mr. Bates 6 has shewn by
the comparison of various closely-allied groups of insects from
the temperate and tropical regions, that this view cannot be
maintained ; and the evidence becomes conclusive when bril-
liantly-coloured males and plain-coloured females of the same
species inhabit the same district, feed on the. same food, and
follow exactly the same habits of life. Even when the sexes
resemble each other, we can hardly believe that their brilliant
and beautifully-arranged colours are the purposeless result of
the nature of the tissues and of the action of the surrounding
conditions.
With animals of all kinds, whenever colour has been modified
for some special purpose, this has been, as far as we can judge,
either for direct or indirect protection, or as an attraction between
the sexes. With many species of butterflies the upper surfaces
of the wings are obscure; and this in all probability leads
to their escaping observation and danger. But butterflies
would be particularly liable to be attacked by their enemies
when at rest ; and most kinds whilst resting raise their wings
vertically over their backs, so that the lower surface alone is
exposed to view. Hence it is this side which is often coloured
so as to imitate the objects on which these insects commonly
rest. Dr. Ebssler, I believe, first noticed the similarity of the
closed wings of certain VanessaB and other butterflies to the
bark of trees. Many analogous and striking facts could be
given. The most interesting one is that recorded by Mr.
Wallace 7 of a common Indian and Sumatran butterfly (Kallima),
which disappears like magic when it settles on a bush ; for it
hides its head and antennae between its closed wings, which,
in form, colour and veining, cannot be distinguished from a
withered leaf with its footstalk. In some other cases the lower
8 'The Naturalist on the Ama- 1867, p. 10. A woodcut of th*
zoos/ vol. i. 1863, p. 19. Kallima is given by Mr. Wallace in
7 S?e the interesting article in ' Hard wickers Science Gossip,' Sept,
the * Westminster Review,' July 1867, p. 196.
312 The Descent of Man. Pabt IL
surfaces of the wings are brilliantly coloured, and jet are
protective ; thus in Thecla rubi the wings when closed are of an
emerald green, and resemble the young leaves of the bramble,
on which in spring this butterfly may often be seen seated. It is
also remarkable that in very many species in which the sexes
differ greatly in colour on their upper surface, the lower surface
is closely similar or identical in both sexes, and serves as a
protection. 8
Although the obscure tints both of the up])er and under
sides of many butterflies no doubt serve to conceal them, yet we
cannot extend this view to the brilliant and conspicuous colours
on the upper surface of such species as our admiral and peacock
Vanessse, our white cabbage-butterflies (Pieris), or the great
swallow-tail Papilio which haunts the open fens — for these
butterflies are thus rendered visible to every living creature.
In these species both sexes are alike ; but in the common brim-
stone butterfly (Gonepteryx rhamni), the male is of an intense
yellow, whilst the female is much paler; and in the orange-
tip (Anthocharis cardamines) the males alone have their wings
tipped with bright orange. Both the males and females in
these cases are conspicuous, and it is not credible that their
difference in colour should stand in any relation to ordinary
protection. Prof. Weismann remarks, 9 that the female of one of
the LycsensB expands her brown wings when she settles on
the ground, and is then almost invisible ; the male, on the other
hand, as if aware of the danger incurred from the bright blue of
the upper surface of his wings, rests with them closed ; and this
shews that the blue colour cannot be in any way protective.
Nevertheless, it is probable that conspicuous colours are in-
directly beneficial to many species, as a warning that they are
unpalatable. For in certain other cases, beauty has been gained
through the imitation of other beautiful species, which inhabit
the same district and enjoy an immunity from attack by being
in some way offensive to their enemies; but then we have to
account for the beauty of the imitated species.
As Mr. Walsh has remarkad to me, the females of our orange-
tip butterfly, above referred to, and of an American species
(Anth. genutia) probably shew us the primordial colours of the
parent-species of the genus; for both sexes of four or five
widely-distributed species are coloured in nearly the same
manner. As in several previous cases, we may here infer that
it is the males of Anth. cardamines and genutia which have
departed from the usual type of the genus. In the Anth. sara
8 Mr. G. Fraser, in < Nature,' 9 < Einfluss der Isolirong anf di»
April 1871, p. 489. Artbildimg,' 1872, p. 58.
Chap. XI. Butterflies and Moths. 3 1 3
from California, the orange-tips to the wings have been partially
developed in the female ; but they are paler than in the male, and
slightly different in some other respects. In an allied Indian
form, the Iphias glaucippe, the orange-tips are fully developed in
both sexes. In this Iphias, as pointed out to me by Mr. A. Butler,
the under surface of the wings marvellously resembles a pale-
coloured leaf; and in our English orange-tip, the under surface
resembles the flower-head of the wild parsley, on which the
butterfly often rests at night. 10 The same reason which compels
us to believe that the lower surfaces have here been coloured for
the sake of protection, leads us to deny that the wings have
been tipped with bright orange for the same purpose, especially
when this character is confined to the males.
Most Moths rest motionless during the whole or greater part
of the day with their wings depressed ; and the whole upper
surface is often shaded and coloured in an admirable manner, as
Mr. Wallace has remarked, for escaping detection. The front-
wings of the Bombycidse and Noctuidse, 11 when at rest, generally
overlap and conceal the hind- wings; so that the latter might be
brightly coloured without much risk; and they are in fact
often thus coloured. During flight, moths would often be able
to escape from their enemies ; nevertheless, as the hind-wings
are then fully exposed to view, their bright colours must
generally have been acquired at some little risk. But the
following fact shews how cautious we ought to be in drawing
conclusions on this head. The common Yellow Under- wings
(TriphsBna) often fly about during the day or early evening, and
are then conspicuous from the colour of their hind- wings. It
would naturally be thought that this would be a source of
danger ; but Mr. J. Jenner Weir believes that it actually serves
them as a means of escape, for birds strike at these brightly
coloured and fragile surfaces, instead of at the body. For in-
stance, Mr. Weir turned into his aviary a vigorous specimen of
Triphcena pronuba, which was instantly pursued by a robin;
but the bird's attention being caught by the coloured wings, the
moth wajs not captured until after about fifty attempts, and
small portions of the wings were repeatedly broken off. He tried
the same experiment, in the open air, with a swallow and T.
fimbria; but the large size of this moth probably interfered
with its capture. 12 We are thus reminded of a statement made
10 See the interesting observations Science Gossip/ Sept. 1867, p. 193.
by Mr. T. W. Wood, * The Student/ 12 See also, on this subject, Mr.
Sept. 1868, p. 81. Weir's paper in * Transact. Ent. Soc."
11 Mr. Wallace in 'Hardwicke's 1869, p. 23.
314 The Descent of Man. Past It
by Mr. Wallace, 13 namely, that in the Brazilian forests and
Malayan islands, many common and highly-decorated butterflies
are weak flyers, though furnished with a broad expanse of wing ;
and they " are often captured with pierced and broken wings,
" as if they had been seized by birds, from which they had
" escaped : if the wings had been much smaller in proportion
u to the body, it seems probable that the insect would more
" frequently have been struck or pierced in a vital part, and
*' thus the increased expanse of the wings may have been in-
* directly beneficial."
Display, — The bright colours of many butterflies and of some
moths are specially arranged for display, so that they may be
readily seen. During the night colours are not visible, and
there can be no doubt that the nocturnal moths, taken as a
body, are much less gaily decorated than butterflies, all of
which are diurnal in their habits. But the moths of certain
families, such as the Zygsenidse, several Sphingidse, Uraniidse,
some Arctiidse and Saturniidse, fly about during the day or
early evening, and many of these are extremely beautiful, being
far brighter coloured than the strictly nocturnal kinds. A
few exceptional cases, however, of brightrcoloured nocturnal
species have been recorded. 14
There is evidence of another kind in regard to display.
Butterflies, as before remarked, elevate their wings when at
rest, but whilst basking in the sunshine often alternately raise
and depress them, thus exposing both surfaces to full view ; and
although the lower surface is often coloured in an obscure
manner as a protection, yet in many species it is as highly
decorated as the upper surface, and sometimes in a very
different manner. In some tropical species the lower surface is
even more brilliantly coloured than the upper. 16 In ti?e Eng-
lish fritillaries (Argynnis) the lower surface alone is orna-
mented with shining silver. Nevertheless, as a general rule,
the upper surface, which is probably more fully exposed, is
coloured more brightly and diversely than the lower. Hence
the lower surface generally affords to entomologists the more
11 * Westminster Review/ July Insects of New England,' 1842, p. 315.
1867, p. 16. 15 Such differences between the
14 For instance, Lithosia ; but upper and lower surfaces of the
Prof. Westwood (* Modern Class, of wings of several species of PapiHo,
Insects,' vol. ii. p. 390) seems sur- may be seen in the beautiful plates
prised at this case. On the relative to Mr. Wallace's * Memoir on the
colours of diurnal and nocturnal Papilionidse of the Malayan Region/
Lepidoptera, see ibid. pp. 333 and in * Transact. Linn. Soc.' vol. xxv.
S92 j also Harris, 4 Treatise on the part i. 1865.
Chap. XI Butterflies and Moths. 315
useful character for detecting the affinities of the various
species. Fritz Mull er informs me that three species of Castnia
are found near his house in S. Brazil : of two of them the hind-
wings are obscure, and are always covered by the front- winga
when these butterflies are at rest; but the third species has
black hind-wings, beautifully spotted with red and white, and
these are fully expanded and displayed whenever the butterfly
rests. Other such cases could be added.
If we now turn to the enormous group of moths, which, as
I hear from Mr. Stainton, do not habitually expose the under
surface of their wings to full view, we find this side very rarely
coloured with a brightness greater than, or even equal to, that
of the upper side. Some exceptions to the rule, either real or
apparent, must be noticed, as the case of Hypopyra. 16 Mr.
Trimen informs me that in Guenee's great work, three moths
are figured, in which the under surface is much the more
brilliant. For instance, in the Australian Gastrophora the
upper surface of the fore-wing is pale greyish-ochreous, while
the lower surface is magnificently ornamented by an ocellus of
cobalt-blue, placed in the midst of a black mark, surrounded
by orange-yellow, and this by bluish^white. But the habits of
these three moths are unknown ; so that no explanation can be
given of their unusual style of colouring. Mr. Trimen also
informs me that the lower surface of the wings in certain other
GeometrsB 17 and quadrifid NoctusB are either more variegated
or more brightly-coloured than the upper surface; but some of
these species have the habit of " holding their wings quite erect
" over their backs, retaining them in this position for a con-
" siderable time," and thus exposing the under surface to view.
Other species, when settled on the ground or herbage, now and
then suddenly and slightly lift up their wings. Hence the lower
surface of the wings being brighter than the upper surface
in certain moths is not so anomalous as it at first appears.
The Saturniidae include some of the most beautiful of all
moths, their wings being decorated, as in our British Emperor
moth, with fine ocelli ; and Mr. T. W. Wood 18 observes that
they resemble butterflies in some of their movements; "for
" instance, in the gentle waving up and down of the wings as if
" for display, which is more characteristic of diurnal than of
" nocturnal Lepidoptera."
18 See Mr. Wormald on this the GeoinetrcB) in 'Transact. Eat.
vnoth : *Proc. Ent. Soc.' March 2nd, Soc.' new series, vo]. v. pi. xr. and
1868. xvi -
" See also an account of the S. *• * Proc. Ent. Soc. of London/
American genus Erateina (cne of July 6, 1 S68, p. xxyii.
3 * 6 The Descent of Man. Past TI
It is a singular fact that no British moths which are bril-
liantly coloured, and, as far as I can discover, hardly any foreign
species, differ much in colour according to sex ; though this is
the case with many brilliant butterflies. The male, however, oi
one American moth, the Saturnia lo, is described as having its
fore-wings deep yellow, curiously marked with purplish-red
spots ; whilst the wings of the female are purple-brown, marked
with grey lines. 19 The British moths which differ sexually in
colour are all brown, or of various dull yellow tints, or nearly
white. In several speGies the males are much darker than the
females, 20 and these belong to groups which generally fly about
during the afternoon. On the other hand, in many genera, as
Mr. Stainton informs me, the males have the hind- wings whiter
than those of the female — of which fact Agrotis exclamationis
offers a good instance. In the Ghost Moth (Hepialus humuli)
the difference is more strongly marked ; the males being white,
and the females yellow with darker markings. 21 It is probable
that in these cases the males are thus rendered more conspicuous,
and more easily seen by the females whilst flying about in
the dusk.
From the several foregoing facts it is impossible to admit
that the brilliant colours of butterflies, and of some few moths,
have commonly been acquired for the sake of protection. We
have seen that their colours and elegant patterns are arranged
and exhibited as if for display. Hence I am led to believe that
the females prefer or are most excited by the more brilliant
19 Harris, 'Treatise,* &c, edited which were fond of eating othei
by Flint, 1862, p. 395. moths ; so that if the Cycnia was
*° For instance, I observe in my commonly mistaken by British birds
son's cabinet that the males are for the Spilosoma, it would escape
darker than the females in the being devoured, and its white de-
Zasiocampa quercus, Odonestis pota- ceptive colour would thus be highly
toria, Hypogymna dispar, Dasychira beneficial. \
pudibunda, and Cycnia mendica. In 21 It is remarkable, that in the
this latter species the difference in Shetland Islands the male of this
colour between the two sexes is moth, instead of differing widely
strongly marked ; and Mr. Wallace from the female, frequently re-
informs me that we here have, as sembles her closely in colour (see
he believes, an instance of protective Mr. MacLachlan, ' Transact. lint.
mimicry confined to one sex, as Soc* vol. ii. 1866, p. 459). Mr.
will hereafter be more fully ex- G. Fraser suggests (« Nature,* April
plained. The white female of the 1871, p. 489) that at the season of
Cycnia resembles the very common the year when the ghost-moth ap-
Spilosoma menthrasti, both sexes of pears in these northern islands, ths
which are white ; and Mr. Stainton whiteness of the males would not
observed that this latter moth was be needed to render them visible to
rejected with utter disgust by a the females in the twilight night,
whole brood of young turkeys,
Chap. XI. Butterflies and Moths. 31*"
males ; for on any other supposition the males would, as far as
we can see, be ornamented to no purpose. We know that ants
and certain Lamellicorn beetles are capable of feeling an attach-
ment for each other, and that ants recognise their fellows after
an interval of several months. Hence there is no abstract
improbability in the Lepidoptera, which probably stand nearly
or quite as high in the scale as these insects, having sufficient
mental capacity to admire bright colours. They certainly
discover flowers by colour. The Humming-bird Sphinx may
often be seen to swoop down from a distance on a bunch of
flowers in the midst of green foliage ; and I have been assured
by two persons abroad, that these moths repeatedly visit flowers
painted on the walls of a room, and vainly endeavour to insert
their proboscis into them. Fritz MUller informs me that several
kinds of butterflies in S. Brazil shew an unmistakable prefer-
ence for certain colours over others: he observed that they
very often visited the brilliant red flowers of five or six genera of
plants, but never the white or yellow flowering species of the
same and other genera, growing in the same garden; and 1
have received other accounts to the same effect. As I hear
from Mr. Doubleday, the common white butterfly often flies
down to a bit of paper on the ground, no doubt mistaking it
for one of its own species. Mr. Collingwood 22 in speaking of
the difficulty in collecting certain butterflies in the Malay
Archipelago, states that "a dead specimen pinned upon a
" conspicuous twig will often arrest an insect of the same species
" in its headlong flight, and bring it down within easy reach of
" the net, especially if it be of the opposite sex."
The courtship of butterflies is, as before remarked, a prolonged
affair. The males sometimes fight together in rivalry; and
many may be seen pursuing or crowding round the same
female. Unless, then, the females prefer one male to another,
the pairing must be left to mere chance, and this does not
appear probable. If, on the other hand, the females habitually,
or even occasionally, prefer the more beautiful males, the colours
of the latter will have been rendered brighter by degrees, and
will have been transmitted to both sexes or to one sex, according
to the law of inheritance which has prevailed. The process of
sexual selection will have been much facilitated, if the conclusion
can be trusted, arrived at from various kinds of evidence in the
supplement to the ninth chapter; namely, that the males of
many Lepidoptera, at least in the imago state, greatly exceed
the females in number.
Some facts, however, are opposed to the belief that female
** ' Rambles of a Naturalist in the Chinese Seas/ 1868, p. 182.
3 1 8 The Descent of Man. Part II,
butterflies prefer the more beautiful males ; thus, as I hare
been assured by several collectors, fresh females may frequently
be seen paired with battered, faded, or dingy males ; but this is
a circumstance which could hardly fail often to follow from the
males emerging from their cocoons earlier than the females.
With moths of the family of the Bombycidse, the sexes pair
immediately after assuming the imago state; for they cannot
feed, owing to the rudimentary condition of their mouths. The
females, as several entomologists have remarked to me, lie in an
almost torpid state, and appear not to evince the least choice in
regard to their partners. This is the case with the common
silk-moth (B. mori) y as I have been told by some continental
and English breeders. Dr. Wallace, who has had great
experience in breeding Bombyx cynthia, is convinced that the
females evince no choice or preference. He has kept above
300 of these moths together, and has often found the
most vigorous females mated with stunted males. The reverse
appears to occur seldom ; for, as he believes, the more vigorous
males pass over the weakly females, and are attracted by those
endowed with most vitality. Nevertheless, the Bombycidse,
though obscurely-coloured, are often beautiful to our eyes from
their elegant and mottled shades.
I have as yet only referred to the species in which the males
are brighter coloured than the females, and I have attributed
their beauty to the females for many generations having chosen
and paired with the more attractive males. But converse
cases occur, though rarely, in which the females are more
brilliant than the males ; and here, as I believe, the males have
selected the more beautiful females, and have thus slowly added
to their beauty. W« do not know why in various classes of
animals the males of some few species have selected the more
beautiful females instead of having gladly accepted any female,
as seems to be the general rule in the animal kingdom; but it,
contrary to what generally occurs with the Lepidoptera, the
females were much more numerous than the males, the latter
would be likely to pick out the more beautiful females. Mr.
Butler shewed me several species of Callidryas in the British
Museum, in some of which the females equalled, and in others
greatly surpassed the males in beauty; for the females alone
have the borders of their wings suffused with crimson and
orange, and spotted with black. The plainer males of these
species closely resemble each other, showing that here the
females have been modified ; whereas in those cases, where the
males are the more ornate, it is these which have been modified,
the females remaining closely alike.
Chap. XI. Butterflies and Moths. 319
In England we have some analogous cases, though not bo
marked. The females alone of two species of Thecla have a
bright-purple or orange patch on their fore-wings. In Hip-
parchia the sexes do not differ much ; but it is the female of
H. janira which has a conspicuous light-brown patch on her
wings ; and the females of some of the other species are brighter
coloured than their males. Again, the females of Colias edusa
and hyale have " orange or yellow spots on the black marginal
(t border, represented in the males only by thin streaks;" and
in Pieris it is the females which " are ornamented with black
" spots on the fore-wings, and these are only partially present
" in the males." Now the males of many butterflies are known
to support the females during their marriage flight ; but in the
species just named it is the females which support the males ;
so that the part which the two sexes play is reversed, as is their
relative beauty. Throughout the animal kingdom the males
commonly take the more active share in wooing, and their
beauty seems to have been increased by the females having
accepted the more attractive individuals ; but with these but-
terflies, the females take the more active part in the final mar-
riage ceremony, so that we may suppose that they likewise do
so in the wooing; and in this case we can understand how it is
that they have been rendered the more beautiful.' Mr. Meldola,
from whom the foregoing statements have been taken, says in
conclusion ; " Though I am not convinced of the action of
" sexual selection in producing the colours of insects, it cannot
" be denied that these facts are strikingly corroborative of
" Mr. Darwin's views." 2 *
As sexual selection primarily depends on variability, a few
words must be added on this subject. In respect to colour
there is no difficulty, for any number of highly variable Lepi-
doptera could be named. One good instance will suffice. Mr.
Bates shewed me a whole series of specimens of Papilio sesostris
an 1 P. childrence ; in the latter the males varied much in the
extent of the beautifully enamelled green patch on the fore-
wings, and in the size of the white mark, and of the splendid
crimson stripe on the hind- wings ; so that there was a great
contrast amongst the males between the most and the least
gaudy. The male of Papilio sesostris is much less beautiful
than of P. childrence ; and it likewise varies a little in the size of
23 'Nature/ April 27th, 1871, p. whilst pairing. See also Mr. G,
508. Mr. Meldola quotes Donzel, Fraser, in 'Nature/ April 20th,
in ' Soc. Ent. de France/ 1837, p. 1871, p. 489, on the sexual differ-
77, on the flight of butterflies ences of several British to tterflies.
j20 The Descent of Man. Part n
the green patch on the fore-wings, and in the occasional ap-
pearance of the small crimson stripe on the hind-wings,
borrowed, as it would seem, from its own female ; for the femalea
of this and of many other species in the iEneas group possess
this crimson stripe. Hence between the brightest specimens
of P. sesostris and the dullest of P. childrence, there was but a
small interval ; and it was evident that as far as mere varia-
bility is concerned, there would be no difficulty in permanently
increasing the beauty of either species by means of selection.
The variability is here almost confined to the male sex; but
Mr. Wallace and Mr. Bates have shewn 24 that the females of
some species are extremely variable, the males being nearly
constant. In a future chapter I shall have occasion to shew
that the beautiful eye-like spots, or ocelli, found on the wings of
many Lepidoptera, are eminently variable. I may here add
that these ocelli offer a difficulty on the theory of sexual
selection ; for though appearing to us so ornamental, they are
never present in one sex and absent in the other, nor do they
ever differ much in the two sexes. 26 This fact is at present
inexplicable ; but if it should hereafter be found that the for-
mation of an ocellus is due to some change in the tissues
of the wings, for instance, occurring at a very early period ox
development, we might expect, from what we know of the laws
of inheritance, that it would be transmitted to both sexes, though
arising and perfected in one sex alone.
On the whole, although many serious objections may be
urged, it seems probable that most of the brilliantly coloured
species of Lepidoptera owe their colours to sexual selection,
excepting in certain cases, presently to be mentioned, in which
conspicuous colours have been gained through mimicry as
a protection. From the ardour of the male throughout the
animal kingdom, he is generally willing to accept any female ;
and it is the female which usually exerts a choice. Hence, if
sexual selection has been efficient with the Lepidoptera, the
male, when the sexes differ, ought to be the more brilliantly
coloured, and this undoubtedly is the case. When both sexes
are brilliantly coloured and resemble each other, the characters
acquired by the males appear to have been transmitted to both.
24 Wallace on the Papilionidac of tomolog. Soc/ Nov. 19th, 1866. p.
the Malayan Region, in * Transact, si.
Linn. Soc.' vol. xxv. 1865, pp. 8, 25 Mr. Bates was so kind as to
*}6. A striking case of a rare lay this subject before the Entonoo-
variety, strictly intermediate be- logical Society, and I hare received
tween two other well-marked female answers to this effect from scrsral
rarieties, is given by Mr. Wallace, entomologists.
See also Mr. Bates, in ' Proc. En-
Chap. XL Butterflies and Moths. 3 2 1
We are led to this conclusion by cases, even within the same
genus, of gradation from an extraordinary amount of difference
to identity in colour between the two sexes.
But it may be asked whether the differences in colour between
the sexes may not be accounted for by other means besides
sexual selection. Thus the males and females of the same
species of butterfly are in several cases known 26 to inhabit
different stations, the former commonly basking in the sunshine,
the latter haunting gloomy forests. It is therefore possible that
different conditions of life may have acted directly on the two
sexes ; but this is not probable, 27 as in the adu.*t state they are
exposed to different conditions during a very short period ; and
the larvaa of both are exposed to tLe same conditions. Mr.
Wallace believes that the difference between the sexes is due
not so much to the males having been modified, as to the females
having in all or almost all cases acquired dull colours for the
sake of protection. It seems to me, on the contrary, far more
probable that it is the males which have been chiefly modified
through sexual selection, the females having been comparatively
little changed. We can thus understand how it is that the
females of allied species generally resemble one another so much
more closely than do the males. They thus shew us ap-
proximately the primordial colouring of the parent-species of
the group to which they belong. They have, however, almost
always been somewhat modified by the transfer to them of some
of the successive variations, through the accumulation of which
the males were rendered beautiful. But I do not wish to deny
that the females alone of some species may have been specially
modified for protection. In most cases the males and females of
distinct species will have been exposed during their prolonged
larval state to different conditions, and may have been thus
affected ; though with the males any slight change of colour
thus caused will generally have been masked by the brilliant
tints gained through sexual selection. When we treat of Birds,
I shall have to discuss the whole question, as to how far the
differences in colour between the sexes are due to the males
having been modified through sexual selection for ornamental
purposes, or to the females having been modified through
natural selection for the sake of protection, so that I will here
say but little on the subject.
In all the cases in which the more common form of equal
28 H. W. Bates, 'The Naturalist 2T On this whole subject see 'The
cm tV Amazons/ vol. ii. 1863, p. Variation of Animals and Plants
228. A. R. Wallace, in * Transact. wader Domesticat on,' 1868, vol. ii
Juinn. Soc.' vol. xxv. 1865, p. 10. chap, jxiii.
y
322 The Descent of Man. Tart II.
inheritance by both, sexes has prevailed, the selection of bright-
coloured males would, tend to make the females bright-coloured;
and the selection of dull-coloured females would tend, to make
the males dull. If both processes were carried on simultaneously,
they would tend to counteract each other ; and the final result
would depend on whether a greater number of females from
being well protected by obscure colours, or a greater number of
males by being brightly-coloured and thus finding partners,
succeeded in leaving more numerous offspring.
In order to account for the frequent transmission of characters
to one sex alone, Mr. Wallace expresses his belief that the more
common form of equal inheritance by both sexes can be changed
through natural selection into inheritance by one sex alone, but
in favour of this view I can discover no evidence. We know
from what occurs under domestication that new characters often
appear, which from the first are transmitted to one sex alone ;
and by the selection of such variations there would not be the
slightest difficulty in giving bright colours to the males alone,
and at the same time or subsequently, dull colours to the females
alone. In this manner the females of some butterflies and moths
have, it is probable, been rendered inconspicuous for the sake of
protection, and widely different from their males.
I am, however, unwilling without distinct evidence to admit
that two complex processes of selection, each requiring the
transference of new characters to one sex alone, have been
carried on with a multitude of species, — that the males have
been rendered moie brilliant by beating their rivals, and the
females more dull-coloured by having escaped from their
enemies. The male, for instance, of the common brimstone
butterfly (Gonepteryx), is of a far more intense yellow than the
female, though she is equally conspicuous ; and it does not seem
probable that she specially acquired her pale tints as a protec-
tion, though it is probable that the male acquired his bright
colours as a sexual attraction. The female of Anthocharis mr-
damines does not possess the beautiful orange wing-tips of the
male ; consequently she closely resembles the white butterflies
(Pieris) so common in our gardens ; but we have no evidence
that this resemblance is beneficial to her. As, on the other hand,
she resembles both sexes of several other species of the genus
inhabiting various quarters of the world, it is probable that she
has simply retained to a large extent her primordial colours.
Finally, as we have seen, various considerations lead to the
conclusion that with the greater number of brilliantly-coloured
Lepidoptera it is the male which has been chiefly modified
through sexual selection; the amount of difference between
Chap. XI. Butterflies and Moths. 323
the sexes mostly depending on the form of inheritance which
has prevailed. Inheritance is governed by so many unknown
laws or conditions, that it seems to us to act in a capricious
manner j 28 and we can thus, to a certain extent, understand how
it is that with closely allied species the sexes either differ to an
astonishing degree, or are identical in colour. As all the suc-
cessive steps in the process of variation are necessarily trans-
mitted through the female, a greater or less number of such
steps might readily become developed in her ; and thus we can
understand the frequent gradations from an extreme difference
to none at all between the sexes of allied species. These cases of
gradation, it may be added, are much too common to favour the
supposition that we here see females actually undergoing the
process of transition and losing their brightness for the sake of
protection ; for we have every reason to conclude that at any
one time the greater number of species are in a fixed condition.
Mimicry, — This principle was first made clear in an admirable
paper by Mr. Bates, 29 who thus threw a flood of light on many
obscure problems. It had previously been observed that certain
butterflies in S. America belonging to quite distinct families,
resembled the Heliconidae so closely in every stripe and shade of
colour, that they could not be distinguished save by an ex-
perienced entomologist. As the HeliconidsB are coloured in
their usual manner, whilst the others depart from the usual
colouring of the groups to which they belong, it is clear that
the latter are the imitators, and the Heliconidae the imitated.
Mr. Bates further observed that the imitating species are com-
paratively rare, whilst the imitated abound, and that the two
sets live mingled together. From the fact of the Heliconidae
being conspicuous and beautiful insects, yet so numerous in
individuals and species, he concluded that they must be pro-
tected from the attacks of enemies by some secretion or odour ;
and this conclusion has now been amply confirmed, 30 especially
by Mr. Belt. Hence Mr. Bates inferred that the butterflies
which imitate the protected species have acquired their present
marvellously deceptive appearance through variation and natural
selection, in order to be mistaken for the protected kinds, and
tiius to escape being devoured. No explanation is here attempted
of the brilliant colours of the imitated, but only of the imitating
butterflies. We must account for the colours of the former in
the same general manner, as in the cases previously discussed
24 * The Variation of Animals and xxiii. 1862, p. 495.
Plants under Domestication,' vol. ii: 30 * Prcc. Ent. Soc* Dec. Srt^
chap. xii. p. 17. 1866, p. xlv.
?* 4 Transact. Linn. Soc* vol.
i2 ,
324 The Descent of Man. Pari II,
in this chapter. Since the publication of Mr. Bates' paper,
similar and equally striking facts have been observed by
Mr. Wallace in the Malayan region, by Mr. Trimen in South
Africa, and by Mr. Biley in the United States. 81
As some writers have felt much difficulty in understanding
how the first steps in the process of mimicry could have been
effected through natural selection, it may be well to remark that
the process probably commenced long ago between forms not
widely dissimilar in colour. In this case even a slight variation
would be beneficial, if it rendered the one species more like
the other ; and afterwards the imitated species might be modi-
fied to an extreme degree through sexual selection or other
means, and if the changes were gradual, the imitators might
easily be led along the same track, until they differed to an
equally extreme degree from their original condition ; and they
would thus ultimately assume an appearance or colouring wholly
unlike that of the other members of the group to which they
belonged. It should also be remembered that many species of
Lepidoptera are liable to considerable and abrupt variations in
colour. A few instances have been given in this chapter ; and
many more may be found in the papers of Mr. Bates and
Mr. Wallace.
With several species the sexes are alike, and imitate the two
sexes of another species. But Mr. Trimen gives, in the paper
already referred to, three cases in which the sexes of the imitated
■form differ from each other in colour, and the sexes of the
imitating form differ in a like manner. Several cases have also
been recorded where the females alone imitate brilliantly-
coloured and protected species, the males retaining "the
" normal aspect of their immediate congeners." It is here obvious
that the successive variations by which the female has been
modified have been transmitted to her alone. It is, however,
probable that some of the many successive variations would
have been transmitted to, and developed in, the males had
not such males been eliminated by being thus rendered less
attractive to the females; so that only those variations were
preserved which were from the first strictly limited in their
transmission to the female sex. We have a partial illus-
tration of these remarks in a statement by Mr. Belt; 32 that
31 Wal -ace, « Transact. Linn. Soc* 163-168. This latter essay is valu-
vol. xxv. 1865, p. 1 ; also ' Transact, able, as Mr. Riley here discusses all
Ent. Sqc' vol. iv. (3rd series), 1867, the objections which have been
p. 301. Trimen, * Linn. Transact.' raised against Mr. Bates' theory,
vol. xxvi. 1869, p. 497. Riley, 82 * The Naturalist in ^caiagnn,
♦Third Annual Report on the Noxi- 1874, p. 385.
•us Insects of Missouri,' 1871, pp-
oiur. XI. Butterflies and Moths. 325
the males of some of the Leptalides, which imitate protected
species, still retain in a concealed manner some of their original
characters. Thus in the males " the upper half of the lower
" wing is of a pure white, whilst all the rest of the wings is
" barred and spotted with black, red and yellow, like the species
" they mimic. The females have not this white patch, and the
" males usually conceal it by covering it with the upper wing,
" so that I cannot imagine its being of any other use to them
" than as an attraction in courtship, when they exhibit it to the
" females, and thus gratify their deep-seated preference for the
" normal colour of the Order to which the Leptalides belong."
Bright Colours of Caterpillars. — Whilst reflecting on the
beauty of many butterflies, it occurred to me that some cater-
pillars were splendidly coloured ; and as sexual selection could
not possibly have here acted, it appeared rash to attribute the
beauty of the mature insect to this agency, unless the bright
colours of their larvae could be somehow explained. In the
first place, it may be observed that the colours of caterpillars
not stand in any close correlation with those of the mature
insect. Secondly, their bright colours do not serve in any
ordinary manner as a protection. Mr. Bates informs me, as an
instance of this, that the most conspicuous caterpillar which he
ever beheld (that of a Sphinx) lived on the large green leaves of
a tree on the open llanos of South America ; it was about four
inches in length, transversely banded with black and yellow,
and with its head, legs, and tail of a bright red. Hence it
caught the eye of any one who passed by, even at the distance of
many yards, and no doubt that of every passing bird.
I then applied to Mr. Wallace, who has an innate genius foi
solving difficulties. After some consideration he replied : " Most
" caterpillars require protection, as may be inferred from some
" kinds being furnished with spines or irritating hairs, and
" from many being coloured green like the leaves on which they
" feed, or being curiously like the twigs of the trees on which they
" live." Another instance of protection, furnished me by Mr. J.
Mansel Weale, may be added, namely, that there is a caterpillar
of a moth which lives on the mimosas in South Africa, and
fabricates for itself a case quite indistinguishable from the
surrounding thorns. From such considerations Mr. Wallace
thought it probable that conspicuously-coloured caterpillars
were protected by having a nauseous taste ; but as their skin
is extremely tender, and as their intestines readily protrude
from a wound, a slight peck from the beak of a bird would
be as fatal to them as if they had been devoured. Hence, as
326 The Descent of Man. Part Li
Mr. Wallace remarks, " distastefulness alone would be insufficient
" to protect a caterpillar unless some outward sign indicated to
" its would-be destroyer that its prey was a disgusting morsel."
Under these circumstances it would be highly advantageous to
a caterpillar to be instantaneously and certainly recognised as
unpalatable by all birds and other animals. Thus the most
gaudy colours would be serviceable, and might have been
gained by variation and the survival of the most easily-re-
cognised individuals.
This hypothesis appears at first sight very bold, but when it
was brought before the Entomological Society ^ it was supported
by various statements ; and Mr. J. Jenner Weir, who keeps a
large number of birds in an aviary, informs me that he has
made many trials-, and finds no exception to the rule, that ali
caterpillars of nocturnal and retiring habits with smooth skins,
all of a green colour, and ali which imitate twigs, are greedily
devoured by his birds. The hairy and spinose kinds are
invariably rejected, as were four conspicuously-coloured species.
When the birds rejected a caterpillar, they plainly shewed, by
shaking their heads, and cleansing their beaks, that they were
disgusted by the taste. 84 Three conspicuous kinds of cater-
pillars and moths were also given to some lizards and frogs, by
Mr. A. Butler, and were rejected, though other kinds were
eagerly eaten. Thus the probability of Mr. Wallace's view is
confirmed, namely, that certain caterpillars have been made
conspicuous for their own good, so as to be easily recognised by
their enemies, on nearly the same principle that poisons are sold
in coloured bottles by druggists for the good of man. We
cannot, however, at present thus explain the elegant diversity
in the colours of many caterpillars ; but any species which had
at some former period acquired a dull, mottled, or striped appear-
ance, either in imitation of surrounding objects, or from the
direct action of climate, &c, almost certainly would not become
uniform in colour, when its tints were rendered intense and
bright; for in order to make a caterpillar merely conspicuous,
there would be no selection in any definite direction.
Summary and Concluding Remarks on Insects, — Looking back
83 'Proc. Entomolog. Soc.' Dec. analogous facts in the * Third An-
3rd, 1866, p. xlv., and March 4th, nual Report on the Noxious Insecu
1867, p. Ixxx. of Missouri/ 1871, p. 148. Some
34 See Mr. J. Jenner Weir's opposed cases are, however, given by
paper on Insects and Insectivorous Dr. Wallace and M. H. d'Orville;
Birds, in * Transact. Ent. Soc* 1869, see * Zoological Record/ 1869, p.
p. 21 ; also Mr. Butler's paper, 549.
ibid. p. 27. Mr. Riley has give»
Osap. XI. Summary on Insects. 327
to the several Orders, we see that the sexes often differ in
various characters, the meaning of which is not in the least
understood. The sexes, also, often differ in their organs of
sense and means of locomotion, so that the males may quickly
discover and reach the females. They differ still oftener in
the males possessing diversified contrivances for retaining the
females when found. We are, however, here concerned only in
a secondary degree with sexual differences of these kinds.
In almost all the Orders, the males of some species, even of
weak and delicate kinds, are known to be highly pugnacious ;
and some few are furnished with special weapons for fighting
with their rivals. But the law of battle does not prevail nearly
so widely with insects as with the higher animals. Hence it
probably arises, that it is in only a few cases that the males have
been rendered larger and stronger than the females. On the
contrary, they are usually smaller, so that they may be developed
within a shorter time, to be ready in large numbers for the
emergence of the females.
In two families of the Homoptera and in three of the Orthop-
tera, the males alone possess sound-producing organs in an
efficient state. These are used incessantly during the breeding-
season, not only for calling the females, but apparently for
unarming or exciting them in rivalry with other males. No
one who admits the agency of selection of any kind, will, after
reading the above discussion, dispute that these musical instru-
ments have been acquired through sexual selection. In four
other Orders the members of one sex, or more commonly of
both sexes, are provided with organs for producing various
sounds, which apparently serve merely as call-notes. When
both sexes are thus provided, the individuals which were able
to make the loudest or most continuous noise would gain
partners before those which were less noisy, so that their organs
have probably been gained through sexual selection. It is
instructive to reflect on the wonderful diversity of the means
for producing sound, possessed by the males alone, or by both
sexes, in no less than six Orders. We thus learn how effectual
sexual selection has been in leading to modifications which
sometimes, as with the Homoptera, relate to important parts of
the organisation.
From the reasons assigned in the last chapter, it is probable
that the great horns possessed by the males of many Lamel-
licorn, and some other beetles, have been acquired as ornaments.
From the small size of insects, we are apt to undervalue their
appearance. If we could imagine a male Chalcosoma (fig. 16),
with its polished bronzed coat of mail, and its vast complex
328 The Descent of Man. Taut It
horns, magnified to the size of a horse, or even of a dog, it would
be one of the most imposing animals in the world.
The colouring of insects is a complex and obscure subject.
"When the male differs slightly from the female, and neither are
brilliantly-coloured, it is probable that the sexes have varied
in a slightly different manner, and that the variations have been
transmitted by each sex to the same, without any benefit or
evil thus accruing. When the male is brilliantly-coloured and
differs conspicuously from the female, as with some dragon-flies
and many butterflies, it is probable that he owes his colours to
sexual selection ; whilst the female has retained a primordial or
very ancient type of colouring, slightly modified by the agencies
before explained. But in some cases the female has apparently
been made obscure by variations transmitted to her alone,
as a means of direct protection ; and it is almost certain that
she has sometimes been made brilliant* so as to imitate other
protected species inhabiting the same district. When the sexes
resemble each other and both are obscurely coloured, there is
no doubt that they have been in a multitude of cases so coloured
for the sake of protection. So it is in some instances when both
are brightly-coloured, for they thus imitate protected species, or
resemble surrounding objects such as flowers; or they give
notice to their enemies that they are unpalatable. In other
cases in which the sexes resemble each other and are both
brilliant, especially when the colours are arranged for display,
we may conclude that they have been gained by the male sex as
an attraction, and have been transferred to the female. We are
more especially led to this conclusion whenever the same type
of coloration prevails throughout a whole group, and we find
that the males of some species differ widely in colour from
the females, whilst others differ slightly or not at all, with
intermediate gradations connecting these extreme states.
In the same manner as bright colours have often been
partially transferred from the males to the females, so it has
been with the extraordinary horns of many Lamellicorn and
some other beetles. So again, the sound-producing organs
proper to the males of the Homoptera and Orthoptera have
generally been transferred in a rudimentary, or even in a nearly
perfect condition, to the females ; yet not sufficiently perfect to
be of any use. It is also an interesting fact, as bearing on
sexual selection, that the stridulating organs of certain male
OrthQptera are not fully developed until the last moult; and that
the colours of certain male dragon-flies are not fully developed
until some little time after their emergence from the pupal
state, and when they are ready to breed.
Chap. XI. Summary on Insects .. 329
Sexual selection implies that the more attractive individuals
Eire preferred by the opposite sex ; and as with insects, when
tne sexes differ, it is the male which, with some rare exceptions,
is the more ornamented, and departs more from the type to
which the species belongs ; — and as it is the male which searches
eagerly for the female, we must suppose that the females
habitually or occasionally prefer the more beautiful males, and
that these have thus acquired their beauty. That the females
in most or all the orders would have the power of rejecting
any particular male, is probable from the many singular con-
trivances possessed by the males, such as great jaws, adhesive
cushions, spines, elongated legs, &c, for seizing the female ; for
these contrivances shew that there is some difficulty in the act,
so that her concurrence would seem necessary. Judging from
what we know of the perceptive powers and affections of
various insects, there is no antecedent improbability in sexual
selection having come largely into play ; but we have as yet no
direct evidence on this head, and some facts are opposed to the
belief. Nevertheless, when we see many males pursuing the
same female, we can hardly believe that the pairing is left to
blind chance — that the female exerts no choice, and is not
influenced by the gorgeous colours or other ornaments with
which the male is decorated.
If we admit that the females of the Homoptera and Orthoptera
appreciate the musical tones of their male partners, and that the
various instruments have been perfected through sexual se-
lection, there is little improbability in the females of other
insects appreciating beauty in form or colour, and consequently
in such characters having been thus gained by the males. But
from the circumstance of colour being so variable, and from its
having been so often modified for the sake of protection, it is
difficult to decide in how large a proportion of cases sexual
selection has played a part. This is more especially difficult in
those Orders, such as Orthoptera, Hymenoptera, and Coleop-
tera, in which the two sexes rarely differ much in colour; for
we are then left to mere analogy. With the Coleoptera, however,
as before remarked, it is in the great Lamellicorn group, placed
by some authors at the head of the Order, and in which we
sometimes see a mutual attachment between the sexes, that
we find the males of some species possessing weapons for sexual
strife, others furnished with wonderful horns, many with stridu-
lating organs, and others ornamented with splendid metallic
tints. Hence it seems probable that all these characters have
been gained through the same means, namely sexual selection.
*With butterflies we have the best evidence, as the males
330 The Descent of Man. Past IL
sometimes take pains to display their beautiful colours ; and we
cannot believe that they would act thus, unless the display was
of use to them in their courtship.
When we treat of Birds, we shall see that they present in
their secondary sexual characters the closest analogy with
insects. Thus, many male birds are highly pugnacious, and
some are furnished with special weapons for fighting with their
rivals. They possess organs which are used during the breeding-
season for producing vocal and instrumental music. They are
frequently ornamented with combs, horns, wattles and plumes
of the most diversified kinds, and are decorated with beautiful
colours, all evidently for the sake of display. We shall find
that, as with insects, both sexes in certain groups are equally
beautiful, and are equally provided with ornaments which are
usually confined to the male sex. In other groups both sexes
are equally plain-coloured and unornamented. Lastly, in some
few anomalous cases, the females are more beautiful than the
males. We shall often find, in the same group of birds, every
gradation from no difference between the sexes, to an extreme
difference. We shall see that female birds, like female insects,
often possess more or less plain traces or rudiments of characters
which properly belong to the males and are of use only to them.
The analogy, indeed, in all these respects between birds and
insects is curiously close. Whatever explanation applies to the
one class probably applies to the other ; and this explanation,
as we shall hereafter attempt to shew in further detail, is sexual
selection.
CHAPTEB Xn.
Secondaby Sexual Chakaoters of Fishes, Amphibians,
and Eeptiles.
Fishes : Courtship and battles of the males — Larger size of the females
— Males, bright colours and ornamental appendages; other strange
characters — Colours and appendages acquired by the males durind the
breeding-season alone — Fishes with both sexes brilliantly coloured
— Protective colours — The less conspicuous colours of the female cannot
be accounted for on the principle of protection — Male fishes building
nests, and taking charge of the ova and young. Amphibians: Dif-
ferences in structure and colour between the sexes — Vocal organs.
Reptiles : Chelonians — Crocodiles — Snakes, colours in some cases pro-
tective — Lizards, battles of — Ornamental appendages — Strange dif-
ferences in structure between the sexes — Colours — Sexual differences
almost as great as with birds.
We have now arrived at the great sub-kingdom of the Vertebrate,
and will commence with the lowest elass* that of Fishes. The*
Chap. XII. FisJies. 331
males of Plagiostomous fishes (sharks, rays) and of Chimseroid
fishes are provided with claspers which serve to retain the
female, like the various structures possessed by many of the
lower animals. Besides the claspers, the males of many rays
have clusters of strong sharp spines on their heads, and several
rows along " the upper outer surface of their pectoral fins."
These are present in the males of some species, which have
other parts of their bodies smooth. They are only temporarily
developed during the breeding-season ; and Dr. Gunther suspects
that they are brought into action as prehensile organs by the
doubling inwards and downwards of the two sides of the body.
It is a remarkable fact that the females and not the males of
some species, as of Rata clavata, have their backs studded with
large hook-formed spines. 1
The males alone of the capelin (Mallotus vittosus, one of
Salmonidae), are provided with a ridge of closely-set, brush-like
scales, by the aid of which two males, one on each side, hold the
female, whilst she runs with great swiftness on the sandy beach,
and there deposits her spawn. 2 The widely distinct Monacanthus
scopas presents a somewhat analogous structure. The male, as
Dr. Gunther informs me, has a cluster of stiff, straight spines,
like those of a comb, on the sides of the tail ; and these in a
specimen six inches long were nearly one and a half inches in
length ; the female has in the same place a cluster of bristles,
which may be compared with those of a tooth-brush. In
another species, M. peronii, the male has a brush like that
possessed by the female of the last species, whilst the sides of
the tail in the female are smooth. In some other species of the
same genus the tail can be perceived to be a little roughened in
the male and perfectly smooth in the female; and lastly in
others, both sexes have smooth sides.
The males of many fish fight for the possession of the females.
Thus the male stickleback (Gasterosteus leiurus) has been de-
scribed as " mad with delight," when the female comes out of her
hiding-place and surveys the nest which he has made for her.
" He darts round her in every direction, then to his accumulated
u materials for the nest, then back again in an instant ; and as
" she does not advance he endeavours to push her with his snout,
'.' and then tries to pull her by the tail and side-spine to the nest." 8
1 Yarrell's 'Hist, of British 1871, p. 119.
Fishes/ vol. ii. 1836, pp. 417, 425, 3 See Mr. R. Warington's in-
436. Dr. Giinther informs me that teresting articles in * Annals and
the spines in R. clavata are peculiar Mag. of Nat. Hist' Oct. 1852 and
to the female. Nov. 1855.
8 * The American Naturalist/ April
33 2 The Descent of Man. Far* II
The males are said to be polygamists ; 4 they are extraordinarily
bold and pugnacious, whilst "the females are quite pacific."
Their battles are at times desperate; "for these puny com-
" batants fasten tight on each other for several seconds, tumbling
" over and over again, until their strength appears completely
" exhausted." With the rough-tailed stickleback (O. trachurus)
the males whilst fighting swim round and round each other,
biting and endeavouring to pierce each other with their raised
lateral spines. The same writer adds, 5 " the bite of these little
" furies is very severe. They also use their lateral spines with
" such fatal effect, that I have seen one during a battle absolutely
" rip his opponent quite open, so that he sank to the bottom and
" died." When a fish is conquered, " his gallant bearing forsakes
" him ; his gay colours fade away ; and he hides his disgrace
"among his peaceable companions, but is for some time the
" constant object of his conqueror's persecution."
The male salmon is as pugnacious as the little stickleback ;
and so is the male trout, as I hear from Dr. Gunther. Mr. Shaw
saw a violent contest between two male salmon which lasted
the whole day ; and Mr. K. Buist, Superintendent of Fisheries,
informs me that he has often watched from the bridge at Perth
the males driving away their rivals, whilst the females were
spawning. The males " are constantly fighting and tearing each
" other on the spawning-beds, and many so injure each other as
" to cause the death of numbers, many being seen swimming near
" the banks of the river in a state of exhaustion, and apparently
" in a dying state." 6 Mr. Buist informs me, that in June 1868,
the keeper of the Stormontfield breeding-ponds visited the
northern Tyne and found about 300 dead salmon, all of which
with one exception were males ; and he was convinced that they
had lost their lives by fighting.
The most curious point about the male salmon is that during
the breeding-season, besides a slight change in colour, " the
" lower jaw elongates, and a cartilaginous projection turns
" upwards from the point, which, when the jaws are closed,
" occupies a deep cavity between the intermaxillary bones of the
.ipper jaw." 7 (Figs. 27 and 28.) In our salmon this change of
structure lasts only during the breeding-season: but in the
4 Noel Humphreys, * River Gar- experienced observer (Scrope's * Days
dens,' 1857. of Salmon Fishing/ p. 60) remarks
5 Loudon's « Mag. of Nat. History/ that like the stag, the male would,
vol. iii. 1830, p. 331. if he could, keep all other malts
6 4 Th« Field/ June 29th, 1867. away.
For Mr. Shaw's statement, see T Yarrell, * History of BritlBfl
1 Edinburgh Review/ 1843. Another Fishes/ v ). ii. 1836, p. 10.
Chap. XH.
Fishes.
333
Salmo lycaodon of N.-W. America the change, as Mr. J. K. Lord 8
believes, is permanent, and best marked in the older males which
have previously ascended the rivers. In these old males the
jaw becomes developed into an immense hook-like projection, and
Fig. 21. Head of male common salmon (Salmo safcw) during the breeding-season.
TThis drawing, as well as all the others in the present chapter, have been executed
by the well-known artist, Mr. G. Ford, from specimens in the British Museum, under
the kind superintendence of Dr. Gtother.]
fche teeth grow into regular fangs, often more than half an inch
in length. With the European salmon, according to Mr. Lloyd, 9
the temporary hook-like structure serves to strengthen and
8 < The Naturalist in Vancouver's 9 * Scandinavian Adventures,* vol
Island/ vol ' 1866, p 54. i. 1854, pp. 100, 104.
334
The Descent of Man.
Part IL
protect the jaws, when one male charges another with wonderful
violence ; but the greatly developed teeth of the male American
salmon may be compared with the tusks of many male mammals,
and they indicate an offensive rather than a protective purpose.
Fig 23.
Head of female salmon.
The salmon is not the only fish in which the teeth differ in
the two sexes ; as this is the case with many rays. In the
thornback (ftaia clavata) the adult male has sharp, pointed
teeth, directed backwards, whilst those of the female are broad
and flat, and form a pavement ; so that these teeth differ in the
two sexes of the same species more than is usual in distinct
genera of the same family. The teeth of the male become sharp
only when he is adult : whilst young they are broad and flat
Chap. XII. Fishes. 335
like those of the female. As so frequently occurs with secondary
sexual characters, both sexes of some species of rays (for instance
JR. batis), when adult, possess sharp pointed teeth ; and here a
character, proper to and primarily gained by the male, appears
to have been transmitted to the offspring of both sexes. The
teeth are likewise pointed in both sexes of R. maculata, but only
when quite adult ; the males acquiring them at an earlier age
than the females. We shall hereafter meet with analogous
cases in certain birds, in which the male acquires the plumage
common to*both sexes when adult, at a somewhat earlier age than
does the female. With other species of rays the males even when
old never possess sharp teeth, and consequently the adults of both
sexes are provided with broad, flat teeth like those of the young,
and like those of the mature females of the above-mentioned
species. 10 As the rays are bold, strong and voracious fish, we
may suspect that the males require their sharp teeth for fighting
with their rivals ; but as they possess many parts modified and
adapted for the prehension of the female, it is possible that their
teeth may be used for this purpose.
In regard to size, M. Carbonnier ll maintains that the female of
almost all fishes is larger than the male ; and Dr. Giinther does
not know of a single instance in which the male is actually
larger than the female. With some Cyprinodonts the male is
not even half as large. As in many kinds of fishes the males
habitually fight together, it is surprising that they have not
generally become larger and stronger than the females through
the effects of sexual selection. The males suffer from their
small size, for according to M. Carbonnier, they are liable to be
devoured by the females of their own species when carnivorous,
and no doubt by other species. Increased size must be in some
manner of more importance to the females, than strength and
size are to the males for fighting with other males ; and this
perhaps is to allow of the production of a vast number of ova.
In many species the male alone is ornamented with bright
colours ; or these are much brighter in the male than the
female. The male, also, is sometimes provided with appendages
which appoar to be of no more use to him for the ordinary
purposes of life, than are the tail feathers to the peacock. I am
indebted for most of the following facts to the kindness of Dr.
Giinther. There is reason to suspect that many tropical fishes
differ sexually in colour and structure; and there are some
striking cases with our British fishes. The male Callionymus lyra
10 See YarrelPs account of the cellent figure, and p. 422, 432.
rays in his * Hist, of British Fishes/ " As quoted in 'The Fanner,
vol. ii. 1836, p. 416, with an ex- 1S68 S p. 369.
33^
The Descent of Man.
PautIL
has been called the gemmeous dragonet " from its brilliant gem-
" like colours." "When fresh caught from the sea the body is
yellow of various shades, striped and spotted with vivid blue on
the head ; the dorsal tins are pale brown with dark longitudinal
bands; the ventral, caudal, and anal fins being bluish-black.
The female, or sordid dragonet, was considered by Linnaeus, and
by many subsequent naturalists, as a distinct species ; it is of a
dingy reddish-brown, with the dorsal fin brown and the other
Fig. 29. Callionymus lyra. Upper figure, male ; lower figure, female.
N.B. The lower figure is more reduced than the upper.
fins white. The sexes differ also in the proportional size of the
head and mouth, and in the position of the eyes; 12 but the
most striking difference is the extraordinary elongation in the
male (fig. 29) of the dorsal fin. Mr. W. Saville Kent remarks
that this " singular appendage appears from my observations
tc of the species in confinement, to be subservient to the same
" end as the wattles, crests, and other abnormal adjuncts of
u the male in gallinaceous birds, for the purpose of fascinating
12 I have drawn up this description from Yarrell's ' British Fishes.'rol. i.
1836, pp. 261 and 266*
Ciiap. XII.
Fishes.
337
" their mates." ls The young males resemble the adult females
in structure and colour. Throughout the genus Callionymus/ 4
the male is generally much more brightly spotted than the
female, and in several species, not only the dorsal, but the anal
fin is much elongated in the males.
The male of the Cottus scorpius, or sea-scorpion, is slenderer
and smaller than the female. There is also a great difference
in colour between them. It is difficult, as Mr. Lloyd 15 remarks,
" for any one, who has not seen this fish during the spawning-
tc season, when its hues are brightest, to conceive the admixture
" of brilliant colours with which it, in other respects so ill-
" favoured, is at that time adorned." Both sexes of the Labrus
mixtus, although very different in colour, are beautiful; the
male being orange with bright blue stripes, and the female
bright red with some black spots on the back.
Fig. 30. Xipkophorus Hellerii. Upper figure, male ; lower figure, female.
In the very distinct family of the CyprinodontidsB— inhabitants
of the fresh waters of foreign lands— the sexes sometimes differ
much in various characters. In the male of the Mollienesia
petenensis, 16 the dorsal fin is greatly developed and is marked
16 With respect to this and the
following species I am indebted to
Dr. Giinther for information: see
also his paper on the * Fishes of
Central America/ in ' Transact*
Zoolog. Soc.' vol. vi 1868, p. 485.
Z
' 3 * Nature,' July 1873, p. 264.
14 ' Catalogue of Acanth. Fishes
In the British Museum,' by Dr.
Giinther, 1861, pp. 138-151.
15 < Game Birds of Sweden/ &e„
1887, p. 466.
3j8 The Descent of Man. IVkflt
with a row of large, round, ocellated, bright-coloured spots;
whilst the same fin in the female is smaller, of a different shape,
and marked only with irregularly curved brown spots. In the
male the basal margin of the anal fin is also a little produced
and dark coloured. In the male of an allied form, the Xipho-
phorus IJellerii (fig. 30), the inferior margin of the caudal fin is
developed into a long filament, which, as I hear from Dr. Giinther,
is striped with bright colours. This filament does not contain
any muscles, and apparently cannot be of any direct use to the
fish. As in the case of the Callionymus, the males whilst young
resemble the adult females in colour and structure. Sexual
-differences such as these may be strictly compared with those
which are so frequent with gallinaceous birds. 17
In a siluroid fish, inhabiting the fresh waters of South America,
the Plecostomus barbatus 18 (fig. 31), the male has its mouth and
inter-operculum fringed with a beard of stiff hairs, of which the
female shows hardly a trace. These hairs are of the nature of
scales. In another species of the same genus, soft flexible ten-
tacles project from the front part of the head of the male, which
are absent in the female. These tentacles are prolongations of
the true skin, and therefore are not homologous with the stiff
hairs of the former species ; but it can hardly be doubted that
both serve the same purpose. What this purpose may be, it is
difficult to conjectures ornament does not here seem probable,
but we can hardly suppose* that stiff hairs and flexible filaments
can be useful in any ordinary way to the males alone. In that
strange monster, the JJhimcera mo?istrosa, the male has a hook-
shaped bone on the top of the head, directed forwards, with its
end rounded and covered with sharp spines ; in the female " this
" crown is altogether absent," but what its use may be to the
male is utterly unknown. 19
The structures as yet referred to are permanent in the male
after he has arrived at maturity ; but with some Blennies, and in
another allied genus, 20 a crest is developed on the head of the
male only during- the breeding-season, and the body at the same
time becomes more brightly-coloured. There can be little k oubt
that this crest serves as a temporary sexual ornament, fot the
female does not exhibit a trace of it. In other species o&the
same genus both sexes possess a crest, and in at least one sproies
" Dr< Giinther makes this re- Water/ July 1868, p. 377, wirfc, a
mark ; Catalogue of Fishss in the figure. Many other cases coulj&e
British Museum/ vol. iii. 1861, p. added of structures peculiar to ipe
141. male, of which the uses are not
N* See Dr. Giinther on this genus, known.
in <%oc. Zoolog. Soc.' 1868, p. 232. 20 Dr. Giinther, * Catalogue ot
19 $ Buckland, in * Land and Fishes/ vol. iii. pp. 221 and 240,
Csaip.XII. *&
Fishes.
339
>
Fig. 31. Plecostonras barbatus. Upper figure, head of male ; lower figure, female
2 % ■
340 The Descent of Man. C Vkwll
neither sex is thus provided. In many of the Chromidse, foi
instance in Geophagus and especially in Cichla, the males, as 1
hear from Professor Agassiz, 21 have a conspicuous protuberance
on the forehead, which is wholly wanting in the females and in
the young males. Professor Agassiz adds, " I have often
" observed these fishes at the time of spawning when the pro-
" tuberance is largest, and at other seasons when it is totally
" wanting, and the two sexes shew no difference whatever in the
" outline of the profile of the head. I never could ascertain that
" it subserves any special function, and the Indians on the
" Amazon know nothing about its use." These protuberances
resemble, in their periodical appearance, the fleshy caruncles on
the heads of certain birds ; but whether they serve as ornaments
must remain at present doubtful.
I hear from Professor Agassiz and Dr. Giinther, that the males
of those fishes, which differ permanently in colour from the
females, often become more brilliant during the breeding-season.
This is likewise the case with a multitude of fishes, the sexes of
which are identical in colour at all other seasons of the year.
The tench, roach, and perch may be given as instances. The
male salmon at this season is "marked on the cheeks with
" orange-coloured stripes, which give it the appearance of a
" Labrus, and the body partakes of a golden orange tinge. The
" females are dark in colour, and are commonly called black-
" fish." B An analogous and even greater change takes place
with the Salmo eriox or bull trout; the males of the char
(S. umbla) are likewise at twis season rather brighter in colour
than the females. 23 The colours of the pike (Esox reticulatus) of
the United States, especially of the male, become, during the
breeding-season, exceedingly intense, brilliant, and iridescent. 2 *
Another striking instance out of many is afforded by the male
stickleback (Gasterostetts Uiurus), which is described by Mr.
Warington, 25 as being then "beautiful beyond description."
The back and eyes of the female are simply brown, and the belly
white. The eyes of the male, on the other hand, are " of the
" most splendid green, having a metallic lustre like the green
" feathers of some humming-birds. The throat and belly are
" of a bright crimson, the back of an ashy-green, and the whole
" fish appears as though it were somewhat translucent and
21 See also « A Journey in Brazil/ Mag. of Nat. Hktory/ vol. vi. 184 1,
by Prof, and Mrs. Agassiz, 1868, p. p. 440.
220. S4 t "j'jjg American Agriculturist,
K Tarrell, « British Fishes/ vol. 1868, p. 100.
ii. 1836, pp. 10, 12, 35. « * Annals and Mag. of Nat. Hist.
** W. Thompson, in ' Annals and Oct. 1852.
Chai\ XII. Fishes. 341
" glowed with an internal incandescence." After the breeding-
season these colours all change, the throat and belly become of a
paler red, the back more green, and the glowing tints subside.
With respect to the courtship of fishes, other cases have been
observed since the first edition of this book appeared, besides that
already given of the stickleback. Mr. W. S. Kent says that the
male of the Ldbrus mixtus, which, as we have seen, differs in
colour from the female, makes " a deep hollow in the sand of the
" tank, and then endeavours in the most persuasive manner to in-
" duce a female of the same species to share it with him, swim-
" ming backwards and forwards between her and the completed
" nest, and plainly exhibiting the greatest anxiety for her to follow."
The males of Cantharus lineatus become, during the breeding-
season, of deep leaden-black ; they then retire from the shoal, and
excavate a hollow as a nest. " Each male now mounts vigilant
•' guard over his respective hollow, and vigorously attacks and
" drives away any other fish of the same sex. Towards his com-
" panions of the opposite sex his conduct is far different; many of
" the latter are now distended with spawn, and these he endeavours
" by all the means in his power to lure singly to his prepared
" hollow, and there to deposit the myriad ova with which they are
" laden, which he then protects and guards with the greatest care. 26
A more striking case of courtship, as well as of display, by the
males of a Chinese Macropus has been given by M. Carbonnier,
who carefully observed these fishes under confinement. 27 The
males are most beautifully coloured, more so than the females.
During the breeding-season they contend for tho possession of
the females; and, in the act of courtship, expand their fins,
which are spotted and ornamented with brightly coloured rays,
in the same manner, according to M. Carbonnier, as the peacock.
They then also bound about the females with much vivacity, and
appear by " l'etalage de leurs vives couleurs chercher a attirer
" l'attention des femelles, lesquelles ne paraissaient indifferentes
" a ce manage, elles nageaient avec une molle lenteur vers les
" males et semblaient se complaire dans leur voisinage." After
the male has won his bride, he makes a little disc of froth by
blowing air and mucus out of his mouth. He then collects the
fertilised ova, dropped by the female, in his mouth ; and this
caused 3£ Carbonnier much alarm, as he thought that they were
going to be devoured. But the male soon deposits them in the
disc of froth, afterwards guarding them, repairing the froth, and
taking care of the young when hatched. I mention these par-
ticulars because, as we shall presently see, there are fishes, the
*» Mature/ May, 1873, p. 25. 2r 'Bull, de la Soc. d'Acclimat
Paris, July 1869, a&d Jan. 1870,
34^ The Descent of Man. Paet II,
males of "which hatch their eggs in their mouths ; and those who
do not believe in the principle of gradual evolution might ask how
could such a habit have originated ; but the difficulty is much
diminished when we know that there are fishes which thus
collect and carry the eggs; for if delayed by any cause in
depositing them, the habit of hatching them in their mouths
might have been acquired.
To return to our more immediate subject. The case stands
thus : female fishes, as far as I can learn, never willingly spawn
except in the presence of the males ; and the males never fertilise
the ova except in the presence of the females. The males fight
for the possession of the females. In many species, the males
whilst young resemble the females in colour ; but when adult
become much more brilliant, and retain their colours throughout
life. In other species the males become brighter than the females
and otherwise more highly ornamented, only during the season
of love. The males sedulously court the females, and in one
case, as we have seen, take pains in displaying their beauty
before them. Can it be believed that they would thus act to no
purpose during their courtship ? And this would be the case,
unless the females exert some choice and select those males
which please or excite them most. If the female exerts such
choice, all the above facts on the ornamentation of the males
become at once intelligible by the aid of sexual selection.
We have next to enquire whether this view of the bright
colours of certain male fishes having been acquired through
sexual selection can, through the law of the equal transmission of
characters to both sexes, be extended to those groups in which the
males and females are brilliant in the same, or nearly the same
degree and manner. In such a genus as Labrus, which includes
some of the most splendid fishes in the world — for instance, the
Peacock Labrus (L. pavo), described, 38 with pardonable exaggera-
tion, as formed of polished scales of gold, encrusting lapis-lazuli,
rubies, sapphires, emeralds, and amethysts — we may, with much
probability, accept this belief; for we have seen that the sexes in
at least one species of the genus differ greatly in colour. With
some fishes, as with many of the lowest animals, splendid colours
may be the direct result of the nature of their tissues and of the
surrounding conditions, without the aid of selection of any kind.
The gold-fish (Cyprinus auratus), judging from the analogy of
the golden variety of the common carp, is perhaps a case in point,
as it may owe its splendid colours to a single abrupt variation,
due to the conditions to which this fish has been subjected under
48 Bory de Saint Vincent, in * Diet. Class. d'Hist. Nat.' torn. ix. 1826
p 151.
Chap. XII. Fishes. 343
confinement. It is, however, more probable that these colonra
nave been intensified through artificial selection, as this species
nas been carefully bred in China from a remote period. 29 Under
natural conditions it does not seem probable that beings so
nighly organised as fishes, and which live under such complex
relations, should become brilliantly coloured without suffering
.some evil or receiving some benefit from so great a change, and
consequently without the intervention of natural selection.
What, then, are we to conclude in regard to the many fishes,
both sexes of which are splendidly coloured? Mr. Wallace 30
believes that the species which frequent reefs, where corals and
other brightly-coloured organisms abound, are brightly coloured
in order to escape detection by their enemies ; but according to
my recollection they were thus rendered highly conspicuous.
In the fresh- waters of the tropics * there are no brilliantly-
coloured corals or other organisms for the fishes to resemble ;
yet many species in the Amazons are beautifully coloured, and
many of the carnivorous Cyprinidae in India are ornamented
with "bright longitudinal lines of various tints." 31 Mr. M'Clel-
land, in describing these fishes, goes so far as to suppose that
" the peculiar brilliancy of their colours" serves as "a better
" mark for king-fishers, terns, and other birds which are
" destined to keep the number of these fishes in check;" but at
the present day few naturalists will admit that any animal has
been made conspicuous as an aid to its own destruction. It is
possible that certain fishes may have been rendered conspicuous
in order to warn birds and beasts of prey that they were
unpalatable, as explained when treating of caterpillars ; but it
is not, I believe, known that any fish, at least any fresh-water
fish, is rejected from being distasteful to fish-devouring animals.
On the whole, the most probable view in regard to the fishes, of
which both sexes are brilliantly. coloured, is that their colours
were acquired by the males as a sexual ornament, and were
transferred equally, or nearly so, to the other sex.
29 Owing to some remarks on this has been " produced at Hangchow a
subject, made in my work ' On the " variety called the fire-fish, from its
Variation of Animals under Domesti- "intensely red colour. It is uni-
oation/ Mr. W. F. Mayers (' Chinese " versally admired, and there is not
Notes and Queries,' Aug. 1868, p. " a household where it is not cul-
123) has searched the ancient " tivated, in rivalry as to its colour,
Chinese encyclopedias. He finds " and as a source of profit."
that gold-fish were first reared in 30 * Westminster Review,' July
confinement during the Sung Dy- 1867, p. 7.
nasty, which commenced a.d. 960. 31 « Indian Cyprinidse/ by Mr.
Jn the year 1129 these fishes M'Clelland, 'Asiatic Researches,
abounded. In another place it is vol. xix. part ii, 1839, p. 230.
said that since the year 1548 there
344 27'^ Descent of Man, Past H,
We have now to consider whether, when the male differs in a
marked manner from the female in colour or in other orna-
ments, he alone has been modified, the variations being inherited
by his male offspring alone; or whether the female has been
specially modified and rendered inconspicuous for the sake of
protection, such modifications being inherited only by the
females. It is impossible to doubt that colour has been gained
by many fishes as a protection : no one can examine the speckled
upper surface of a flounder, and overlook its resemblance to the
sandy bed of the sea on which it lives. Certain fishes, moreover,
can through the action of the nervous system, change their
colours in adaptation to surrounding objects, and that within a
short time. 32 One of the most striking instances ever recorded
of an animal being protected by its colour (as far as it can bo
judged of in preserved specimens), as well as by its form, is that
given by Dr. Gunther 33 of a pipe-fish, which, with its reddish
streaming filaments, is hardly distinguishable from the sea-weed
to which it clings with its prehensile tail. But the question now
under consideration is whether the females alone have been
modified for this object. We can see that, one sex will not be
modified through natural selection for the sake of protection
more than the other, supposing both to vary, unless one sex is
exposed for a longer period to danger, or has less power of
escaping from such danger than the other; and it does not
appear that with fishes the sexes differ in these respects. As
far as there is any difference, the males, from being generally
smaller and from wandering more about, are exposed to greater
danger than the females; and yet, when the sexes differ, the
males are almost always the more conspicuously coloured.
The ova are fertilised immediately after being deposited; and
when this process lasts for several days, as in the case of
the salmon, 34 the female, during the whole time, is attended by
the male. After the ova are fertilised they are, in most cases,
left unprotected by both parents, so that the males and females,
as far as oviposition is concerned, are equally exposed to danger,
and both are equally important for the production of fertile ova ;
consequently the more or less brightly-coloured individuals ot
either sex would be equally liable to be destroyed or preserved,
and both would have an equal influence on the colours of their
offspring.
Certain fishes, belonging to several families, make nests, and
some of them take care of their young when hatched. Both
** G. Pouchet, L'Institut. Nov. 1, 327, pi. xiv. and xr.
L871, p. 134. " Yarrell, * British Fisfce*/ to]
w 'Froc. Zoolog. Soc' 1865, p. \l p, H
Chap. XII.' Fishes. 34S
sexes of the bright coloured Crenilabrus massa and melops wort
together in building their nests with sea-weed, shells, &C. 86
But the males of certain fishes do all the work, and afterwards
take exclusive charge of the young. This is the case with the dull-
coloured gobies, 88 in which the sexes are not known to differ in
colour, and likewise with the sticklebacks (Grasterosteus), in which
the males become brilliantly coloured during the spawning season.
The male of the smooth-tailed stickleback (G. leiurus) performs
the duties of a nurse with exemplary care and vigilance during
a long time, and is continually employed in gently leading back
the young to the nest, when they stray too far. He courageously
drives away all enemies, including the females of his own species.
it would indeed be no small relief to the male, if the female, after
depositing her eggs, were immediately devoured by some enemy,
for he is forced incessantly to drive her from the nest. 37
The males of certain other fishes inhabiting South America
and Ceylon, belonging to two distinct Orders, have the extra-
ordinary habit of hatching within their mouths or branchial
cavities, the eggs laid by the females. 88 I am informed by
Professor Agassiz that the males of the Amazonian species
which follow this habit, " not only are generally brighter than
" the females, but the difference is greater at the spawning-season
" than at any other time." The species of Geophagus act in the
same manner ; and in this genus, a conspicuous protuberance
becomes developed on the forehead of the males during the
breeding-season. With the various species of Chromids, as
Professor Agassiz likewise informs me, sexual differences in
colour may be observed, " whether they lay their eggs in the
" water among aquatic plants, or deposit them in holes, leaving
" them to come out without further care, or build shallow nests
" in the river mud, over which they sit, as our Pomotis does.
" It ought also to be observed that these sitters are among the
" brightest species in their respective families ; for instance,
" Hygrogonus is bright green, with large black ocelli, encircled
" with the most brilliant red." Whether with all the species of
Chromids it is the male alone which sits on the eggs is not
known. It is, however, manifest that the fact of the eggs being
85 According to the observations nals and Mag. of Nat. Hist.' Novem-
of M. Gerbe ; see Giinther's * Record ber 1855.
cf Zoolog. Literature/ 1865, p. M Prof. Wvman, in ' Proc. Boston
\ 94. Soc. of Nat. "Hist/ Sept. 15, 1857.
86 Cuvier, * Regne Animal/ vol. Also Prof. Turner, in * Journal of
J, 1829, p. 242. Anatomy and Phys.' Nov. 1, 1866,
17 See Mr. Warington's most p. 78. Dr. Giinther has likewia«
interesting description of the habits described other casss,
of the GasterosieHsIeiurw, in 'An-
346 The Descent of Man, Pabi II
protected or unprotected by the parents, has had little or no
influence on the differences in colour between the sexes. It is
further manifest, in all the cases in which the males take
exclusive charge of the nests and young, that the destruction
of the blighter-coloured males would be far more influential on
the character of the race, than the destruction of the brighter-
coloured females ; for the death of the male during the period of
incubation or nursing would entail the death of the young, so
that they could not inherit his peculiarities; yet, in many of
these very cases the males are more conspicuously coloured than
the females.
In most of the Lophobranchii (Pipe-fish, Hippocampi, &c.)
the males have either marsupial sacks or hemispherical de-
pressions on the abdomen, in which fche ova laid by the female
are hatched. The males also shew great attachment to their
young. 39 The sexes do not commonly differ much in colour;
but Dr. Giinther believes that the male Hippocampi are rather
brighter than the females. The genus Solenostoma, however,
offers a curious exceptional case, 40 for the female is much more
vividly-coloured and spotted than the male, and she alone has a
marsupial sack and hatches the eggs; so that the female of
Solenostoma differs from all the other Lophobranchii in this
latter respect, and from almost all other fishes, in being more
brightly-coloured than the male. It is improbable that this
remarkable double inversion of character in the female sho # uld
be an accidental coincidence. As the males of several fishes,
whiGh take exclusive charge of the eggs and young, are more
brightly coloured than the females, and as here the female Sole-
nostoma takes the same charge and is brighter than the male, it
might be argued that the conspicuous colours of that sex which
is the more important of the two for the welfare of the offspring,
must be in some manner protective. But from the large number
of fishes, of which the males are either permanently or period-
ically brighter than the females, but whose life is not at all
more important for the welfare of the species than that of the
female, this view can hardly be maintained. When we treat
of birds we shall meet with analogous cases, where there has
been a complete inversion of the usual attributes of the two
sexes, and we shall then give what appears to be the probable
explanation, namely, that the males have selected the more
attractive females, instead of the latter having selected, in
3° Yarrell, « Hist, of British Fishes of Zanzibar/ by Col. Playfair,
Fishes,* vol. ii. 1836, pp. 329, 338. 1866, p. 137, has re-examined th»
*• Dr. Giinther, since publishing specimens, and has given .me the
in account of this species in 'The above information.
Chap. XII* Fishes 347
accordance with the usual rule throughout the animal kingdom,
the more attractive males. ' . .
On the whole we may conclude, that with most fishes, in
which the sexes differ in colour or in other ornamental charac-
ters, the males originally varied, with their variations trans-
mitted to the same sex, and accumulated through sexual
selection by attracting or exciting the females. In many cases,
however, such characters have been transferred, either partially
or completely, to the females. In other cases, again, both sexes
have been coloured alike for the sake of protection ; but in
no instance does it appear that the female alone has had her
colours or other characters specially modified for this latter
purpose.
The last point which need be noticed is that fishes are known
to make various noises, some of which are described as being
musical. Dr. Dufosse, who has especially attended to this
subject, says that the sounds are voluntarily produced in several
ways by different fishes : by the friction of the pharyngeal bones
— by the vibration of certain muscles attached to the swim-
bladder, which serves as a resounding board — and by the vibra-
tion of the intrinsic muscles of the swim-bladder. By this latter
means the Trigla produces pure and long-drawn sounds which
range over nearly an octave. But the most interesting case for
us is that of two species of Ophidium, in which the males alone
are provided with a sound-producing apparatus, consisting of
small movable bones, with proper muscles, in connection with
the swim-bladder. 41 The drumming of the Umbrinas in the
European seas is said to be audible from a depth of twenty
fathoms ; and the fishermen of Eochelle assert " that the males
" alone make the noise during the spawning-time ; and that it
" is possible by imitating it, to take them without bait." 42 From
this statement, and more especially from the case of Ophidium,
it is almost certain that in this, the lowest class of the Yerte-
brata, as with so many insects and spiders, sound-producing
instruments have, at least in some cases, been developed through
sexual selection, as a means for bringing the sexes together.
41 ' Comptes Rendus.' Tom. xlvi. the Dutch translation of this work
1858, p. 353. Tom. xlvii. 1858, p. (vol. ii., p. 36), gives some further
916. Tom. liv. 1862, p. 393. The particulars on the sounds made by
noist; made by the Umbrinas {Scwsna fishes.
aquild), is said by some authors to 42 The Rev. C. Kingsley, in
be more like that of a flute or organ, ' Nature/ May 1870, p. 40.
than drumming : Dr. Zouteveen, in
348
The Descent of Man,
Part II.
Amphibians.
Urodela. — I will begin with the tailed amphibians. The sexes
of salamanders or newts often differ much both in colour and
structure. In some species prehensile claws are developed on
the fore-legs of the males during the breeding-season : and at
this season in the male Triton palmipes the hind-feet are pro-
vided with a swimming-web, which is almost completely
absorbed during the winter; so that their feet then resemble
Fig. 32. Triton cristatus (half natural size, from BU's « British Reptiles ')•
Upper figure, male during the breeding-season; lower figure, female.
those of the female. 43 This structure no doubt aids the male
in his eager search and pursuit of the female. Whilst courting
her he rapidly vibrates the end of his tail. With our common
newts (Triton punctatm and cristatus) a deep, much indented
crest is developed along the back and tail of the male during the
breeding-season, which disappears during the winter. Mr. St.
George Mivart informs me that it is not furnished with muscles,
and therefore cannot be used for locomotion. As during the
season of courtship it becomes edged with bright colours, there
can hardly be a doubt that it is a masculine ornament. In
many species the body presents strongly contrasted, though
lurid tints, and these become more vivid during the breeding-
season. The male, for instance, of our common little newt
(Triton punctatus) is "brownish-grey above, passing into yellow
« 3 Bell, ' History of British Reptiles,' 2nd edit. 1849, pp. 156-159,
Chap. XII Amphibians, 349
" beneath, which in the spring becomes a rich bright orange,
" marked everywhere with round dark spots." The edge of the
crest also is then tipped with bright red or violet The female
is usually of a yellowish-brown colour with scattered brown
dots, and the lower surface is often quite plain.* 4 The young
are obscurely tinted. The ova are fertilised during the act of
deposition, and are not subsequently tended by either parent.
We may therefore conclude that the males have acquired their
strongly-marked colours and ornamental appendages through
sexual selection ; these being transmitted either to the male
offspring alone, or to both sexes.
Anura or Batrachia, — With many frogs and toads the colours
evidently serve as a protection, such as the bright green tints
of tree-frogs and the obscure mottled shades of many terrestrial
species. The most conspicuously-coloured toad whieh I ever
saw, the Phryniwus nigricans , 45 had the whole upper surface of
the body as black as ink, with the soles of the feet and parts of
the abdomen spotted with the brightest vermilion. It crawled
about the bare sandy or open grassy plains of La Plata under a
scorching sun, and could not fail to catch the eye of every pass-
ing creature. These colours are probably beneficial by making
this animal known to all birds of prey as a nauseous mouthful.
In Nicaragua there is a little frog " dressed in a bright livery
" of red and blue " which does not conceal itself like most other
species, but hops about during the daytime, and Mr. Belt says 46
that as soon as he saw its happy sense of security, he felt sure
that it was uneatable. After several trials he succeeded in
tempting a young duck to snatch up a young one, but it was
instantly rejected ; and the duck " went about jerking its head,
" as if trying to throw off some unpleasant taste."
With respect to sexual differences of colour, Dr. Giinther
does not know of any striking instance either with frogs or
toads ; yet he can often distinguish the male from the female, by
the tints of the former being a little more intense. Nor does
he know of any striking difference in external structure between
the sexes, excepting the prominences which become developed
during the breeding-season on the front-legs of the male, by
which he is enabled to hold the female. 47 It is surprising that
44 Bell, * History of British Rep- sikmmensis (Dr. Anderson, * Proc.
tiles/ 2nd edit. 1849, pp. 146, 151. Zoolog. Soc.,' 1871, p. 204) has two
45 * Zoology of the Voyage of the plate-like callosities on the thorax
" Beagle," * 1843. Bell, ibid. p. 49. and certain rugosities on the lingers,
46 * The Naturalist in Nicaragua/ which perhaps subserve the same en**
1874, p. 321. as the above-mentioned prominence*
47 The male alone of the Bufo
350 The Descent of Man. PaiitU
these animals have not acquired more strongly-marked sexual
characters; for though cold-blooded their passions are strong
Dr. G-unther informs me that he has several times found an
unfortunate female toad dead and smothered from having been
so closely embraced by three or four males. Frogs have been
observed by Professor Hoffman in Giessen fighting all day long
during the breeding-season, and with so much violence, that one
had its body ripped open.
Frogs and toads offer 'one interesting sexual difference, namely,
in the musical powers possessed by the males; but to speak
of music, when applied to the discordant and overwhelming
sounds emitted by male bull-frogs and some other species, seems,
according to our taste, a singularly inappropriate expression.
Nevertheless, certain frogs sing in a decidedly pleasing manner.
Near Rio Janeiro I used often to sit in the evening to listen to a
number of little Hylse, perched on blades of grass close to the
water, which sent forth sweet chirping notes in harmony. The
various sounds are emitted chiefly by the males during the
breeding-season, as in the case of the croaking of our common
frog. 48 In accordance with this fact the vocal organs of the
males are more highly-developed than those of the females. In
some genera the males alone are provided with sacs which open
into the larynx. 49 For instance, in the edible frog (Bana esculenta)
"the sacs are peculiar tc the males, and become, when filled
" with air in the act of croaking, large globular bladders, stand-
" ing out one on each side of the head, near the corners of the
* f mouth." The croak of the male is thus rendered exceedingly
powerful ; whilst that of the female is only a slight groaning
noise. 60 In the several genera of the family the vocal organs
differ considerably in structure, and their development in all
cases may be attributed to sexual selection.
Bkptiles.
Chelonia. — Tortoises and turtles do not offer well-marked
sexual differences. In some species, the tail of the male is
longer than that of the female. In some, the plastron or lower
surface of the shell of the male is slightly concave in relation to
the back of the female. The male of the mud-turtle of the
United States (Chrgsemys picta) has claws on its front-feet
twice as long as those of the female ; and these are used when
** Bell, * History of British *• J. Bishop, in * Todd's Cyclop.
Reptiles/ 1849, p. 93. of Anat. and Phvs.' vol. iv. p. 1503
*> Bell, ibid. p. 112-114.
Oil A*. £11. Reptiles. 351
the sexes unite. 61 With the huge tortoise of the Galapagos
Islands (Testudo nigra) the males are said to grow to a larger
size than the females: during the pairing-season, and at no
other time, the male utters a hoarse bellowing noise, which can
be heard at the distanco of more than a hundred yards ; the
female, on the other hand, never uses her voice. 62
With the Testudo elegans of India, it is said " that the combats
" of the males may be heard at some distance, from the noise
" they produce in butting against each other." M
Crocodilia.— The sexes apparently do not differ in colour ; nor
do I know that the males fight together, though this is pro-
bable, for some kinds make a prodigious display before the
females. Bartram 64 describes the male alligator as striving
to win the female by splashing and roaring in the midst
of a lagoon, "swollen to an extent ready to burst, with its
" head and tail lifted up, he spins or twirls round on the
" surface of the water, like an Indian chief rehearsing his feats
of war." During the season of love, a musky odour is emitted
by the submaxillary glands of the crocodile, and pervades their
haunts. 56 ■ ■ .
Ophidia. — Dr. Gunther informs me that the males are always
smaller than the females, and generally have longer and slenderer
tails ; but he knows of no other difference in external structure.
In regard to colour, he can almost always distinguish the male
from the female by his more strongly-pronounced tints ; thus
the black zigzag band on the back of the male English viper is
more distinctly denned than in the female. The difference js
much plainer in the rattle-snakes of N. America, the male of
which, as the keeper in the Zoological Gardens shewed me, can at
once be distinguished from the female by having more lurid
yellow about its whole body. In S. Africa the Bucephalus
capensis presents an analogous difference, for the female "is
" never so fully variegated with yellow on the sides as the
" male." fi6 The male of the Indian Dipsas cynodon, on the
other hand, is blackish-brown, with the belly partly black,
whilst the female is reddish or yellowish-olive, with the belly
either uniform yellowish or marbled with black. In the Tragops
dispar of the same country, the male is bright green, and the
"Mr.- C. J. Maynard, « The British India/ 1864, p. 7.
American Naturalist,* Dec. 1869, p. ** 'Travels through Carolina,
555. &c, 1791, p. 128.
52 See ray ' Journal of Researches 65 Owen, * Anatomy of Verte-
during the Voyage of the " Beagle," ' bratcs,' vol. i. 1866, p. 615.
1845, p. 384. 66 Sir Andrew Smith, ' Zoolog. of
* 3 Dr Gunther, « Reptiles of S. Africa : Repdlia,' 1849, pi. x.
352 The Descent of Man. PAtiT II
female bronze-coloured. 67 No doubt the colours of some snakes
axo protective, as shewn by the green tints of tree-snakes, and
the various mottled shades of the species which live in sandy
places ; but it is doubtful whether the colours of many kinds,
for instance of the common English snake and viper, serve to
conceal them; and this is still more doubtful with the many
foreign species which are coloured with extreme elegance. The
colours of oertain species are very different in the adult and
young states. 58
During the breeding-season the anal scent-glands of snakes are
in active function ; 69 and so it is with the same glands in lizards,
and as we have seen with the submaxillary glands of crocodiles.
As the males of most animals search for the females, these
odoriferous glands probably serve to excite or charm the fen ale,
rather than to guide her to the spot where the male may be
found. Male snakes, though appearing so sluggish, are amorous ;
for many have been observed crowding round the same female,
and even round her dead body. They are not known to
fight together from rivalry. Their intellectual powers are
higher than might have been anticipated. In the Zoological
Gardens they soon learn not to strike at the iron bar with which
their cages are cleaned ; and Dr. Keen of Philadelphia informs
me that some snakes which he kept, learned after four or five
times to avoid a noose, with which they were at first easily
caught. An excellent observer in Ceylon, Mr. E. Layard, saw 15 °
a cobra thrust its head through a narrow hole and swallow a
toad. " With this encumbrance he could not withdraw him-
" self; finding this, he reluctantly disgorged the precious mor-
" sel, which began to move off; this was too much for snake
" philosophy to bear, and the toad was again seized, and again
" was the snake, after violent efforts to escape, compelled to part
" with its prey. This time, however, a lesson had been learnt,
" and the toad was seized by one leg, withdrawn, and then
" swallowed in triumph."
The keeper in the Zoological Gardens is positive that certain
snakes, for instance Crotalus and Python, distinguish him from
all other persons. Cobras kept together in the same ca£?
apparently feel some attachment towards each other. 61
* 7 Dr. A. Giinther, * Reptiles of brates,' vol. i. 1866, p. 615.
British India,' Ray Soc 1864, pp. tf0 * Rambles in Ceylon,' in * Aimau
304, 308. and Mag. of Nat. Hist.' 2nd sene*,
* 8 Dr. Stoliczka, « Journal of vol. ix. 1852, p. 333.
Asiatic Soc. of Bengal,' vol. xxxix. al Dr. Giinther, * Reptiles of
1870, pp. 205, 211. British India/ 1864, p 340.
69 Owen, 'Anatomy of Verte-
Ohak XII. Reptiles. 353
It does not, however, follow because snakes have some
reasoning power, strong passions and mutual affection, that they
should likewise be endowed with sufficient, taste to admire
brilliant colours in their partners, so as to lead to the adorn-
ment of the species through sexual selection. Nevertheless, it is
difficult to account in any other manner for the extreme teauty
of certain species ; for instance, of the coral-snakes of S. America,
which are of a rich red with black and yellow transverse bands.
I well remember how much surprise I felt at the beauty of the
first coral-snake which I saw gliding across a path in Brazil.
Snakes coloured in this peculiar manner, as Mr. Wallace states
on the autnority of Dr. Gunther, 62 are found nowhere else
in the world except in S. America, and here no less than four
genera occur. One of these, Elaps, is venomous ; a second and
widely-distinct genus is doubtfully venomous, and the two
others are quite harmless. The species belonging to these
distinct genera inhabit the same districts, and are so like each
other, that no one "but a naturalist would distinguish the
" harmless from the poisonous kinds." Hence, as Mr. Wallace
believes, the innocuous kinds have probably acquired their
colours as a protection, on the principle of imitation ; for they
would naturally be thought dangerous by their enemies. The
cause, however, of the bright colours of the venomous Elaps
remains to bo explained, and this may perhaps be sexual
selection.
Snakes produce other sounds besides hissing. The deadly
Echis carinata has on its sides some oblique rows of scales of a
peculiar structure with serrated edges ; and when this snake is
excited, these scales are rubbed against each other, which pro-
duces " a curious prolonged, almost hissing sound." 63 With
respect to the rattling of the rattle-snake, we have at last some
definite information : for Professor Aughey states, 64 that on twc
occasions, being himself unseen, he watched from a little distance,
a rattle-snake coiled up with head erect, which continued to
rattle at short intervals for half an hour : and at last he saw
another snake approach, and when they mot they paired.
Hence he is satisfied that one of the uses of the rattle is to bring
the sexes together. Unfortunately he did not ascertain whether
it was the male or the female which remained stationary and
called for the other. But it by no means follows from the
above fact that the rattle may not be of use to these snakes in
other ways, as a warning to animals which would otherwise
68 < Westminster Review/ July 1st, Soc/ 1871, p. 196.
1867, p. 32. ** * The American Naturalist, 1
»W. Anderson, 'Proc. Zoolog. 1873, p. 85.
2 A
354 3H** Descent of Man, Part U ,
attack them. Nor can I quite disbelieve the several accounts
which have appeared of their thus paralysing their prey with fear.
Some other snakes also make a distinct noise by rapidly vibrating
their tails against the surrounding stalks of plants ; and I have my-
self heard this in the case of a Trigonocephalus in S. America.
Lacertilia.— The males of some, probably of many kinds of
lizards fight together from rivalry. Thus the arboreal Anolis
cristatellus of S. America is extremely pugnacious : "During the
" spring and early part of the summer, two adult males rarely
" meet without a contest. On first seeing one another, they nod
" their heads up and down three or four times, and at the same
" time expanding the frill or pouch beneath the throat ; their
" eyes glisten with rage, and after waving their tails from
" side to side for a few seconds, as if to gather energy, they dart
" at each other furiously, rolling over and over, and holding
(S firmly with their teeth. The conflict generally ends in one of
"* the combatants losing his tail, which is often devoured by the
" victor." The male of this species is considerably larger than
the female; 66 and this, as far as Dr. GUnther has been able to
ascertain, is the general rule with lizards of all kinds. The
males alone of the Cyrtodactylus rubidus of the Andaman Islands
possesses pre-anal pores ; and these pores judging from analogy
probably serve to emit an odour. 66
The sexes often differ greatly in various external characters.
The male of the above-mentioned Anolis is furnished with a
crest which runs along the back and tail, and can be erected at
pleasure ; but of this crest the female does not exhibit a trace.
In the Indian Cophotis ceylanica, the female has a dorsal crest,
though much less developed than in the male ; and so it is, as
Dr. Giinther informs me, with the females of many Iguanas,
Chameleons, and other lizards. In some species, however, the
crest is equally developed in both sexes, as in the Iguana tubercu-
lata. In the genus Sitana, the males alone are furnished with a
large throat-pouch (fig. 33), which can be folded up like a fan,
and is coloured blue, black, and red ; but these splendid colours
are exhibited only during the pairing-season. The female does
not possess even a rudiment of this appendage. In the Anolis
crtstateUus, according to Mr. Austen, the throat pouch, which is
bright red marbled with yellow, is present in the female, though
in a rudimental condition. Again, in certain other lizards, both
sexes are equally well provided with throat pouches. Here we
M Mr. N. L. Austen kept these 6S Stoliczka, ' Journal of Asiatic
animals alive for a considerable Soc. of Bengal,* vol. xxxir. 1870, p.
time ; see * Land and Water/ July 166.
1867, p.
Chap. Xlt
Reptiles.
3S5
Fig. 31. Sitana minor. Male with t'»e
gular pouch expanded (Irom Giintlier's
* Reptiles of India ')•
see with species belonging to the same group, as in so many-
previous cases, the same character either confined to the males,
or more largely developed in them than in the females, or
again equally developed in both sexes. The little lizards of
the genus Draco, which glide
through the air on their rib-
supported parachutes, and
which in the beauty of their
colours baffle description, are
furnished with skinny appen-
dages to the throat ." like the
wattles of gallinaceous birds."
These become erected when
the animal is excited. They
occur in both sexes, but are
best developed when the male
arrives at maturity, at which
age the middle appendage is
sometimes twice as long as the head. Most of the species like-
wise have a low crest running along the neck ; and this is much
more developed in the full-grown males, than in the females or
young males. 67
A Chinese species is said to live
in pairs during the spring ; " and if
" one is caught, the other falls from
" the tree to the ground, and allows
" itself to be captured with impu-
t6 nity/'— I presume from despair. 6 *
There are other and much more
remarkable differences between the
sexes of certain lizards. The male
of Ceraiophora aspsra bears on the
extremity of his snout an appendage
half as long as the head. It is
cylindrical, covered with scales,
flexible, and apparently capable of
erection: in the female it is quite
rudimental. In a second species
of the same genus a terminal scale
forms a minute horn on the summit of the flexible appendage;
Y ^} t ? ie f° re & oin g statements nificent work on the 'Reptiles ot
Fig. 34. Ceratopnora Stoddartii
LTpper figure, male ; lower figure,
female.
and quotations, in regard to Cophotis,
Sitana and Draco, as well as the
following facts in regard to Cerato-
phora and Chamaeleon, are from Dr.
Gtinther himself, or from his mag-
British India,' Ray Soc. 1864, pp.
122, 130, 135.
68 Mr. Swinhoe, 'Proc. Zoolog.
Soc.' 1870, p. 240.
2 a 2
SSo
The Descent of Man.
t*AfiT It
and in a third species (C. Stoddartii, fig. 34) the whole appen-
dage is converted into a horn, which is usually of a white
colour, but assumes a purplish tint when the animal is excited.
In the adult male of this latter species the horn is half an inch
in length, but it is of quite minute size in the female and in the
yoang. These appendages, as Dr. Giinther has remarked to me,
may be compared with the combs of gallinaceous birds, and
apparently serve as ornaments.
Fig. 35. Chamseleon bifurcus. Upper figure, male ; lower figure, female.
In the genus Chamseleon we come to the acme of difference
between the sexes. The upper part of the skull of the male
C. bifurcus (fig. 35), an inhabitant of Madagascar, is produced
into two great, solid, bony projections, covered with scales like
the rest of the head; and of this wonderful modification of
structure the feiwle exhibits only a rudiment. Again, in
Chap. XII.
Reptiles.
357
Chamcelem Owenii (tig. 36), from the West Coast of Africa, the
male bears on his snout and forehead three curious horns, of
which the female has not a trace. These horns consist of an
excrescence of bone covered with a smooth sheath, forming part of
the general integu-
ments of the body,
so that they are
identical in struc-
ture with those of a
bull, goat, or other
sheath -horned ru-
minant. Although
the three horns
differ so much in
appearance from
the two great pro-
longations of the
skull in C. h'furcus,
we can hardly doubt
that they serve the
same general pur-
pose in the economy
of these two ani-
mals. The first con-
jecture, which will occur to every one, is that they are UFed
by the males for fighting together; and as these animals are
very quarrelsome, 69 this is probably a correct view. Mr. T. \V.
Wood also informs me that he once watched two individuals of
C. pumilus, fighting violently on the branch of a tree ; they flung
their heads about and tried to bite each other ; they then rested
for a time, and afterwards continued their battle.
With many lizards, the sexes differ slightly in colour, the
tints and stripes of the males being brighter and more distinctly
defined, than in the females. This, for instance, is the case with
the above Cophotis and with the Acanthodactylus capensis of
S. Africa. In a Cordylus of the latter country, the male is
either much redder or greener than the female. In the Indian
Calotes nigrilabris there is a still greater difference ; the lips also
of the male are black, whilst those of the female are green. In
our common little viviparous lizard (Zootoca vivipara) "the
" under side of the body and base of the tail in the male are
" bright orange, spotted with black ; in the female these parts
"are pale-greyish-green without spots" 70 We have seen that
69 Dr. Bucholz, * Monatsbericht ™ Bell, < History of British
K. Preuss. Akad.' Jan. 1$74 ? p. 78. Eeptiles,' 2nd edit. 1849, p. 40.
Fig 36. Cbanueleon Owenii. Upper figure, male
lower figure, female.
358 The Descent of Man, Pabt II.
the males alone of Sitana possess a throat-pouch ; and this is
splendidly tinted with blue, black, and red. In the Proctotretus
tenuis of Chile the male alone is marked with spots of blue,
green, and coppery-red. 71 In many cases the males retain the
same colours throughout the year, but in others they become
much brighter during the breeding-season; I may give as an
additional instance the Calotes maria, which at this season has a
bright red head, the rest of the body being green. 72
Both sexes of many species are beautifully coloured exactly
alike ; and there is no reason to suppose that such colours are
protective. No doubt with the bright green kinds which live
in the midst of vegetation, this colour serves to conceal them ;
and in N. Patagonia I saw a lizard {Proctotretus multimaculatus)
which, when frightened, flattened its body, closed its eyes, and
then from its mottled tints was hardly distinguishable from the
surrounding sand. But the bright colours with which so many
lizards are ornamented, as well as their various curious appen-
dages, were probably acquired by the males as an attraction,
and then transmitted either to their male offspring alone, or to
both sexes. Sexual selection, indeed, seems to have played
almost as important a part with reptiles as with birds ; and the
less conspicuous colours of the females in comparison with the
males cannot be accounted for, as Mr. Wallace believes to be the
case with birds, by the greater exposure of the females to danger
during incubation.
CHAPTER XKL
Secondary Sexual Characters op Birds.
Sexual differences — Law of battle — Special weapons — Vocal organs —
Instrumental music — Love-antics and dances — Decorations, permanent
and seasonal — Double and single annual moults — Display of ornaments
by the males.
Secondary sexual characters are more diversified and con-
spicuous in birds, though not perhaps entailing more important
changes of structure, than in any other class of animals. I shall,
therefore, treat the subject at considerable length. Male birds
sometimes, though rarely, possess special weapons for fighting
,l For Proctotretus see ' Zoology the Indian Calotes, see ' Reptiles of
of the Voyage of the "Beagle:" British India/ by Dr Giinther, p.
Keptiles,' by Mr. Bell, p. 8. For 143.
the Lizards of S. Africa, see * Zoology n Giinther m * Proc. £oolog. Soc'
of S. Africa: Reptiles,' by Sir 1870, p. 778, with a coloured
Andrew Smith, pi. 25 and 39. For figure.
Chap. XIIT, Birds. 359
with each other. They charm the female by vocal or instru-
mental music of the most varied kinds. They are ornamented
by all sorts of combs, wattles, protuberances, horns, air-distended
sacks, top-knots, naked shafts, plumes and lengthened feathers
gracefully springing from all parts of the body. The beak and
naked skin about the head, and the feathers are often gorgeously
coloured. The males sometimes pay their court by dancing, or
by fantastic antics performed either on the ground or in the air.
In one instance, at least, the male emits a musky odour, which
we may suppose serves to charm or excite the female ; for that
excellent observer, Mr. Bamsay, 1 says of the Australian musk-
duck (Biziura lobata) that " the smell which the male emits
" during the summer months is confined to that sex, and in
" some individuals is retained throughout the year ; I have
" never, even in the breeding-season, shot a female which had
" any smell of musk." So powerful is this odour during the
pairing-season, that it can be detected long before the bird can
be seen. 2 On the whole, birds appear to be the most aesthetic of
all animals, excepting of course man, and they have nearly the
same taste for the beautiful as we have. This is shewn by our
enjoyment of the singing of birds, and by our women, both
civilised and savage, decking their heads with borrowed plumes,
and using gems which are hardly more brilliantly coloured than
the naked skin and wattles of certain birds. In man, however,
when cultivated, the sense of beauty is manifestly a far more
complex feeling, and is associated with various intellectual
Before treating of the sexual characters with which we are
here more particularly concerned, I may just allude to certain
differences between the sexes which apparently depend on
differences in their habits of life; for such cases, though
common in the lower, are rare in the higher classes. Two
humming-birds belonging to the genus Eustephanus, which
inhabit the island of Juan Fernandez, were long thought to be
specifically distinct, but are now known, as Mr. Gould informs
me, to be the male and female of the same species, and they
differ slightly in the form of the beak. In another genus of
humming-birds (Grypus), the beak of the male is serrated along
the margin and hooked at the extremity, thus differing much
from that of the female. In the Neomorpha of New Zealand,
there is, as we have seen, a still wider difference in the form of
the beak in relation to the manner of feeding of the two sexes.
Something of the same kind has been observed with the gold-
1 ' Ibis,' vol. iii-(new series) 1867, 2 Gould, ' Handbook to the Birds
p. 414. of Australia/ 1865, vol. ii. p. 383.
360 Tlie Descent of Man. Part H
finch (Carduelis elegant), for I am assured by Mr. J. Jenner Weir
that the birdcatchers can distinguish the males by their slightly
longer beaks. The flocks of males are often found feeding on
the seeds of the teazle (Dipsacus), which they can reach with
their elongated beaks, whilst the females more commonly feed
on the seeds of the betony or Scrophularia. With a slight
difference of this kind as a foundation, we can see how the beaks
of the two sexes might be made to differ greatly through natural
selection. In some of the above cases, however, it is possible
that the beaks of the males may have been first modified in
relation to their contests with other males; and that this
afterwards led to slightly changed habits of life.
Law of Battle. — Almost all male birds are extremely pug-
nacious, using their beaks, wings, and legs for fighting together.
We see this every spring with our robins and sparrows. The
smallest of all birds, namely the humming-bird, is one of the
most quarrelsome. Mr. Gosse 8 describes a battle in which a
pair seized hold of each other's beaks, and whirled round and
round, till they almost fell to the ground ; and M. Montes de
Oca, in speaking of another genus of humming-bird, says that
two males rarely meet without a fierce aerial encounter : when
kept in cages " their fighting has mostly ended in the splitting of
" the tongue of one of the two, which then surely dies from
" being unable to feed."* With Waders, the males of the
common water-hen (Gallinula chloropus) "when pairing, fight
"violently for the females: they stand nearly upright in the
" water and strike with their feet." Two were seen to be thus
engaged for half an hour, until one got hold of the head of the
other, which would have be6n killed, had not the observer
interfered; the female all the time looking on as a quiet spec-
tator. 6 Mr. Blyth informs me that the males of an allied bird
(Gallicrex cristatus) are a third larger than the females, and are
so pugnacious during the breeding-season, that they are kept by
the natives of Eastern Bengal for the sake of fighting. Various
other birds are kept in India for the same purpose, for instance,
the bulbuls (Pycnonotus hsemorrhous) which " fight with great
"spirit." 6
The polygamous ruff (Machetes pugnax, fig. 37) is notorious
for his extreme pugnacity ; and in the spring, the males, which
are considerably larger than the females, congregate day after
3 Quoted by Mr. Gould, ' Intro- Ireland : Birds/ vol. ii. 1850, p
Auction to the Trochilidae/ 1861, 327.
p. 29. • Jerdon, « Birds of India/ 1863;
4 Gould, ibid. p. 52. rol. ii. p. 96.
* W Thompson, * Nat. Hist, of
Chap. XIIT.
Law of Battle.
361
day at a particular spot, where the females propose to lay their
eggs. The fowlers discover these spots by the turf being
trampled somewhat bare. Here they fight very much like game-
cocks, seizing each other with their beaks and striking with
their wings. The great ruff of feathers round the neck is then
erected, and according to Col. Montagu " sweeps the ground as
** a shield to defend the more tender parts;" and this is the only
362 The Descent of Man. Part II
instance known to me in the case of birds, of any structure
serving as a shield. The ruff of feathers, however, from its
varied and rich colours probably serves in chief part as an orna-
ment. Like most pugnacious birds, they seem always ready to
fight, and when closely confined often kill each other; but
Montagu observed that their pugnacity becomes greater during
the spring, when the long feathers on their necks are fully
developed ; and at this period the least movement by any one
bird provokes a general battle. 7 Of the pugnacity of web-footed
birds, two instances will suffice : in Guiana " bloody fights occur
*' during the breeding-season between the males of the wild
" musk-duck (Cairina moschata); and where these fights have
" occurred the river is covered for some distance with feathers." 8
Birds which seem ill-adapted for fighting engage in fierce con-
flicts ; thus the stronger males of the pelican drive away the
weaker ones, snapping with their huge beaks and giving heavy
blows with their wings. Male snipe fight together, "tugging
" and pushing each other with their bills in the most curious
" manner imaginable/' Some few birds are believed never to
fight ; this is the case, according to Audubon, with one of the
woodpeckers of the United States (Picus auratus), although " the
" hens are followed by even half a dozen of their gay suitors." 9
The males of many birds are larger than the females, and this
no doubt is the result of the advantage gained by the larger and
stronger males over their rivals during many generations. The
difference in size between the two sexes is carried to an extreme
point in several Australian species ; thus the male musk-duck
(Biziura) and the male Cincloramphus cruratis (allied to our
pipits) are by measurement actually twice as large as their
respective females. 10 With many other birds the females are
larger than the males ; and as formerly remarked, the explana-
tion often given, namely, that the females have most of the work
in feeding their young, will not suffice. In some few cases, as
we shall hereafter see, the females apparently have acquired
their greater size and strength for the sake of conquering other
females and obtaining possession of the males.
The males of many gallinaceous birds, especially of the poly-
gamous kinds, are furnished with special weapons for fighting
with their rivals, namely spurs, which can be used with fearful
7 Macgillivray, ' Hist. Brit. i. p. 191. For pelicans and snipes,
Birds/ vol. iv. 1852, pp. 177-181. see vol. iii. pp. 138, 477.
8 Sir R. Schomburgk, in ' Journal 10 Gould, * Handbook of Birds or
of R. Geograph. Soc' vol. xiii. 1843, Australia,* vol. i. p. 395 ; vol it p.
p. 31. 383
9 'Ornithological Biography,* vol.
Chap. XIII. Law of Battle, 363
effect. It has been recorded by a trustworthy writer n that in
Derbyshire a kite struck at a game-hen accompanied by her
chickens, when the cock rushed to the rescue, and drove his
spur right through the eye and skull of the aggressor. The
spur was with difficulty drawn from the skull, and as the kite
though dead retained his grasp, the two birds were firmly
locked together; but the cock when disentangled was very
little injured. The invincible courage of the game-cock is
notorious: a gentleman who long ago witnessed the brutal
scene, told me that a bird had both its legs broken by some
accident in the cockpit, and the owner laid a wager that if the
legs could be spliced so that the bird could stand upright, he
would continue fighting. This was effected on the spot, and the
bird fought with undaunted courage until he received his death-
stroke. In Ceylon a closely allied, wild species, the Gallus
Stanleyi, is known to fight desperately "in defence of his
" seraglio," so that one of the combatants is frequently found
dead. 12 An Indian partridge ( Ortygornis gularis), the male of
which is furnished with strong and sharp spurs, is so quarrel-
some, " that the scars of former fights disfigure the breast of
" almost every bird you kill." 13
The males of almost all gallinaceous birds, even those which
are not furnished with spurs, engage during the breeding-season
in fierce conflicts. The Capercailzie and Black-cock (Tetrao
urogallm and T. tetrix), which are both polygamists, have regular
appointed places, where during many weeks they congregate in
numbers to fight together and to display their charms before the
females. Dr. W. Kovalevsky informs me that in Russia he has
soon the snow all bloody on the arenas where the capercailzie
ha ve fought ; and the black-cocks " make the feathers fly in every
" direction/' when several " engage in a battle royal." The
elder Brehm gives a curious account of the Balz, as the love-
dances and love-songs of the Black-cock are called in Germany.
The bird utters almost continuously the strangest noises : " he
u holds his tail up and spreads it out like a fan,~he lifts up his
" head and neck with all the feathers erect, and stretches his
u wings from the body. Then he takes a few jumps in different
" directions, sometimes in a circle, and presses the under part of
" his beak so hard against the ground that the chin feathers are
" rubbed off. During these movements he beats his wings and
w turns round and round. The more ardent he grows the more
" lively he becomes, until at last the bird appears like a frantic
11 Mr. Hewitt in the 'Poultry Nat. Hist.' vol. xiv. 1854, p. 63.
Book by Tegetmeier/ 1866, p. 137* 13 Jerdon, * Birds of India./ roL
'* Layard, 'Annals and Mag. of iii. p. 5" 4.*
364 The Descent of Man. Part IL
" creature." At such times the black-cocks are so absorbed that
they become almost blind and dea£ but less so than the caper-
cailzie : hence bird after bird may be shot on the same spot, or
even caught by the hand. After performing these antics the
males begin to fight : and the same black-cock, in order to prove
his strength over several antagonists, will visit in the course of
one morning several Balz-places, which remain the same during
successive years. 14
The peacock with his long train appears more like a dandy
than a warrior, but he sometimes engages in fierce contests : the
Rev. W. Darwin Fox informs me that at some little distance
from Chester two peacocks became so excited whilst fighting,
that they flew over the whole city, still engaged, until they
alighted on the top of St. John's tower.
The spur, in those gallinaceous birds which are thus provided,
is generally single ; but Polyplectron (see fig. 51, p. 397) has two
or more on each leg ; and one of the Blood- pheasants (Ithayinis
cruentus) has been seen with five spurs. The spurs are generally
confined to the male, being represented by mere knobs or rudi-
ments in the female ; but the females of the Java peacock (Pavo
muticus) and, as I am informed by Mr. Blyth, of the small fire-
backed pheasant (Euplocamus erythropthalmus) possess spurs.
In Galloperdix it is usual for the males to have two spurs, and
for the females to have only one on each leg. 15 Hence spurs may
be considered as a masculine structure, which has been occasion-
ally more or less transferred to the females. Like most other
secondary sexual characters, the spurs are highly variable, both
in number and development, in the same species.
Various birds have spurs on their wings. But the Egyptian
goose (Chenalopex cegyptiacus) has only "bare obtuse knobs," and
these probably shew us the first steps by which true spurs have
been developed in other species. In the spur-winged goose,
Plectropterus gambensis, the males have much larger spurs than
the females ; and they use them, as I am informed by Mr.
Bartlett, in fighting together, so that, in this case, the wing-spurs
serve as sexual weapons ; but according to Livingstone, they are
chiefly used in the defeLue of the young. The Palamedea
(fig. 38) is armed with a pair of spurs on each wing ; and these
are such formidable weapons, that a single blow has been known
to drive a dog howling away. But it does not appear that the
spurs in this case, or in that of some of the spur-winged rails,
14 Brehm, ' Must. Thierleben, Sweden,' &c, 1867, p. 79.
1867, B. iv. s. 351. Some of the ,5 Jerdon, 'Birds of India: on
foregoing statements are taken from Ithaginis, vol. iii. p. 523 ; on Gano-
id Lloyd, 'The Game Birds of perdix, p. 541.
<Map. Xffi.
LaW of Baltfe.
3&5
are larger in the male than in the female. 16 In certain plovers,
however, the wing-spurs must be considered as a sexual cha-
-4' ,
Fig. 33. Palamedea cornuta (from Brehm), shewing the double wing-spurs, and the
filament on the head.
10 For the Egyptian goose, see p. 639. For Plectropterus, < Living-
Macgillivray, < British Birds/ vol. iv. stone's Travels/ p. 254, For Fala-
366 The Descent of Man. Vaw It
racter. Thus in the male of our common peewit ( Vanellus cris-
tatus) the tubercle on the shoulder of the wing becomes more
prominent during the breeding-season, and the males fight
together. In some species of Lobivanellus a similar tubercle
becomes developed during the breeding-season "into a short
" horny spur." In the Australian L. lobatus both sexes have spurs,
but these are much larger in the males than in the females. In
an allied bird, the Hoplopterus armatus, the spurs do not increase
in size during the breeding-season ; but these birds have been
seen in Egypt to fight together, in the same manner as our
peewits, by turning suddenly in the air and striking sideways
at each other, sometimes with fatal results. Thus also they
drive away other enemies. 17
The season of love is that of battle ; but the males of some
birds, as of the game-fowl and ruff, and even the young males of
the wild turkey and grouse, 18 are ready to fight whenever they
meet. The presence of the female is the teterrima belli causa.
The Bengali baboos make the pretty little males of the amadavat
(Estrelda amandava) fight together by placing three small cages
in a row, with a female in the middle ; after a little time the two
males are turn 
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