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http://www.archive.org/details/cu31924024753851
THE DESCENT OF MAN
AND
SELECTION IN RELATION TO SEX
BY
CHARLES DARWIN, M.A., LL.D., F.R.S.
PART ONE
NEW YORK
P. F. COLLIER & SON
MCMII
2 \4 oles
1 3650
SCIENCE
PREFACE TO THE SECOND EDITION
DuRin@ the successive reprints of the first edition of this
work, published in 1871, I was able to introduce several im-
portant corrections; and now that more time has elapsed, 1
have endeavored 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 in-
debted to a large number of correspondents for the commu-
nication 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drawings have been replaced by better ones, done from life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 Profes-
sor 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 observations, because during the last few years sev-
eral memoirs on the subject have appeared on the Conti-
nent, 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 se-
lection of such variations as are often called spontaneous;
whereas, even in the first edition of the ‘‘Origin of Species,”’
T distinctly stated that great weight must be attributed to
the inherited effects of use and disuse, with respect both
| (8)
4 PREFACE TO THE SECOND EDITION
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 structure; nor must we forget what
I have called ‘‘correlated’’ growth, meaning thereby, that
various parts of the organization are in some unknown man-
ner so connected, that when one part varies, so do others;
and if variations in the one are accumulated 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
of 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-favorable criticisms on
sexual selection with those which appeared at first on natu-
ral selection; such as, that it would explain some few de-
tails, but certainly was not applicable to the extent to which
Ihave employed it. My conviction of the power of sexual
selection remains unshaken; but it is probable, or almost
certain, that several of my conclusions 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 be-
lieve, be much more largely accepted; and it has already
been fully and favorably received by several capable judges.
Down, BECKENHAM, KENT,
September, 1874
TABLE
OF THE
PRINCIPAL ADDITIONS AND CORRECTIONS TO
THE PRESENT EDITION
First Edition
Present Edition
Vou. I. Vol, I.
Page Page
22 33-35 Discussion on the rudimentary
points in the human ear re-
vised.
26 38 Cases of men born with hairy
bodies.
27, note. 39, note. |Mantegazza on the last molar.
tooth in man.
29 42-43 |The rudiments of a tail in man.
32, note. 44, note. | Bianconi on homologous struct-
ures, a8 explained by adapta-
tion on mechanical principles.
40 101 Intelligence in a baboon.
42 102 Sense of humor in dogs.
44 104-105 | Further facts on imitation in man
and animals.
47 106 Reasoning power in the lower
animals.
50 113-114 Pes of experience by ani-
mals.
53 117 Power of abstraction in animals.
58 124-125 |Power of forming concepts in re-
lation to language.
64 128 Pleasure from certain sounds,
colors, and forms.
78 142 Fidelity in the elephant.
79 148 Galton on gregariousness of
cattle.
eae =) 144-145 | Parental affection.
the ip, note. 158, note. |! Persistence of enmity and hatred.
@)
6 TABLE OF THE PRINCIPAL ADDITIONS AND
First Edition Present Edition
Vol. L Vol. L
Page Page
91 155 Nature and strength of shame,
regret, and remorse.
94 ° 159, note. {Suicide among savages.
97 163, note. |The motives of conduct.
112 49 Selection, as applied to primeval
man.
122 58-59 Resemblances between idiots and
animals.
124, note. 61, note. | Division of the malar bone.
125, note. | 59-60, note. |Supernumerary mamme and
igits.
128-129 64-65 Further cases of muscles proper
to animals appearing in man.
146 81, note. |Broca: average capacity of skull
diminished by the preservation
of the inferior members of
society.
149 84 Belt on advantages to man from
his hairlessness.
150 85-86 Disappearance of the tail in man
and certain monkeys.
169 180-181 |Injurious forms of selection in
civilized nations.
180 192 Indolence of man, when free from
a struggle for existence.
193 208 Gorilla protecting himself from
rain with his hands,
208, note. | 216, note. | Hermaphroditism in fish.
209 218 Rudimentary mammeze in male
mammals.
239 248-251 | Changed conditions lessen fertil-
; ity and cause ill-health among
savages.
245 257-260 |Darkness of skin a protection
against the sun.
250 263-273 | Note oy Professor Huxley on the
development of the brain in
man and apes.
256 276-278 |Special organs of male parasitic
worms for holding the female,
CORRECTIONS TO THE PRESENT EDITION 7
First Edition
Present Edition
Vol. I. Vol. I.
Page Page
275-276 295-297 |Greater variability of male than
female; direct action of the en-
vironment in causing differ-
ences between the sexes.
290 “310 Period of development of pro-
tuberances on birds’ heads de-
termines their transmission to
one or both sexes.
301 821-323 |Causes of excess of male births.
314 336 Proportion of the sexes in the
bee family.
815 338-340 |Excess of males perhaps some-
times detuned by selection.
327 350 Bright colors of lowly organized
animals. ;
838 859 Sexual] selection among spiders.
339 360 Cause of smallness of male
spiders.
345 366 Use of phosphorescence of the
glow-worm.
849 369 The humming noises of flies.
350 370 Use of bright colors to Hemip-
tera ve.
851 370-871 |Musical apparatus of Homoptera.
854 374-875 |Development of stridulating ap-
859 379, note. paratus in Orthoptera.
366 884-885 |Herman Miiller on sexual differ-
ences of bees. ;
387 402 Sounds produced by moths.
397 410 Display of beauty by butter-
flies.
401 414 Female butterflies, taking the
more active part in courtship,
brighter than their males.
412 421-493 |Further cases of mimicry in but-
terflies and moths.
417 424 Cause of bright and diversified
Vol. IL Vol. I. colors of caterpillars.
2 432 Brushlike scales of male Mallo-
tus.
8
TABLE OF THE PRINCIPAL ADDITIONS AND
First Edition
Vol. IL
Present Edition
Vol. UL.
Page Page
14 443-444 |Further facts on courtship of
fishes, and the spawning of
Macropus.
23 451 | Dufossé on the sounds made by
fishes.
26 454 Belt on a frog protected by bright
coloring.
30 458 Further facts on mental powers
of snakes.
82 459 Sounds produced by snakes; the
rattlesnake.
36 463 Combats of Chameleons.
72 496 Marshall on protuberances on
birds’ heads.
91 518 Further facts on display by the
Argus pheasant.
108 530 Attachment between paired birds.
118 5389 Female pigeon rejecting certain
males.
120 541 Albino birds not finding partners,
in a state of nature.
124 545-546 | Direct action of climate on birds’
colors.
147-150 560-569 | Further facts on the ocelli in the
Argus pheasant.
152 571 Display by humming birds in
courtship.
157 574-575 |Cases with pigeons of color trans-
mitted to one sex alone. —
232 640-642 | Taste for the beautiful permanens.
enough to allow of sexual selec-
tion with the lower animals.
247 652 Horns of sheep originally a mas-
culine character.
248 653 nese affecting horns of ani-
mals.
256 662 Prong-horned variety of Cervus
virginianus.
260 666 Relative sizes of male and female
whales and seals.
CORRECTIONS TO THE PRESENT EDITION 9
First Edition
Present Edition
Vol. I. Vol. IL.
Page Page
266 672 _| Absence of tusks in male miocene
igs.
286 690 Dabion on sexual differences of
ats. ;
299 701 Reeks on advantage from pecul-
iar coloring.
316 719 Difference of complexion in men
and women of an African tribe.
337 736 Speech subsequent to singing.
356 154 Schopenhauer on importance of
courtship to mankind.
859 et seg. | 756 et seg. | Revision of discussion on com-
munal marriages and promis-
cuity.
3738 769-770 |Power of choice of woman in
marriage, among savages.
380 776 Long-continued habit of plucking
out hairs may produce an in-
inherited effect.
CONTENTS
INTRODUCTION . - ‘ e 5 . . . . ° .
PART I
THE DESCENT OR ORIGIN OF MAN
CHAPTER I
THE EVIDENCE OF THE DESCENT OF MAN FROM SOME LOWER FORM
Nature of the evidence bearing on the origin of mari—Homologous struc-
tures in man and the lower animals—Miscellaneous points of corre-
spondence—Development—Rudimentary structures, muscles, sense-
organs, hair, bones, reproductive organs, ete. —The bearing of these
three great classes of facts on the origin of man _ . 3 7
CHAPTER II
Nn
21
ON THE MANNER OF DEVELOPMENT OF MAN FROM SOME LOWER FORM
Variability of body and mind in man—Inheritance—Causes of variability
—tLaws of variation the same in man as in the lower animals—Direct
action of the conditions of life—Effects of the increased use and dis-
use 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 struc-
ture—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 skuil—Nakedness—Absence of a tail
—Defenceless condition of man 2 f 3 . . - 7
CHAPTER IIt
£6
COMPARISON OF THE MENTAL POWERS OF MAN AND THE LOWER ANIMALS
The difference in mental power between the highest ape and the lowest
savagé, immeénse—Certain instincts in common—The emotions—
Curiosity—Imitation-— Attention — Memory—Imagination—Reason—
Progressive Improvemetit—Tools and weapons used by animals—
Abstraction, self-consciousness—Language—Sense of beauty—Beliet
in God, spiritual agencies, superstitions . . . . . .
(11)
94
12 CONTENTS
CHAPTER IV
OOMPARISON OF THE MENTAL POWERS OF 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 . : . 134
CHAPTER V
ON THE DEVELOPMENT OF THE INTELLECTUAL AND MORAL FAOULTIES DURING
PRIMEVAL AND CIVILIZED TIMES
Advancement of the intellectual powers through natural selection—Impor-
tance of imitation—Social and moral faculties—Their development
within the limits of the same tribe—Natural selection as affecting civ-
ilized nations—Evidence that civilized nations were once barbarous . 173
CHAPTER VI
ON THE AFFINITIES AND GENEALOGY OF MAN
Position of man in the animal series—The natural system genealogical—
Adaptive characters of slight value—Various small points of resem-
blance between man and ithe Quadrumana—Rank of man in the nat-
ural system—Birthplace and antiquity of man—Absence of fossil con-
necting-links—Lower stages in the genealogy of man, as inferred,
first, from his atiinities, and, secondly, from his structure—LHarly _
androgynous condition of the Vertebrata—Conclusion . ‘ - 196
CHAPTER VII
ON THE RACES OF MAN
The nature and value of specific characters—Application to the races of
man—Arguments in favor of, and opposed to, ranking the so-called
races of man as distinct species—Sub-species—Monogenists and polyg-
enists—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—EHach race ~~’ 7-7 *
' “+ from a single pair—The extinction of races—The fr
The effects of crossing—Slight influence of *
conditions of life—Slight or no influence of
selection . . : : . -¥
CONTENTS
PART II
SEXUAL SELECTION
CHAPTER VIII
PRINOIPLES OF SEXUAL SELECTION
Secondary sexual characters—Sexual selection—Manner of action—Excess
of males—Polygamy—The male alone generally modified through
sexual selection—EHagerness of the male—Variability of the male—
Choice exerted by the female—Sexual compared with natural selec-
tion—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
net modified through sexual selection—Supplement on the proportional
numbers of the two sexes throughout the animal kingdom—tThe pro-
portion of the sexes in relation to natural selection . . .
CHAPTER IX
13
- a4
SECONDARY SEXUAL CHARACTERS IN THE LOWER OLASSES OF THE ANIMAL
KINGDOM
These characters absent in the lowest classes—Brilliant colors—Mollusca—
Annelids—Crustacea, secondary sexual characters strongly developed;
dimorphism ; color; characters not acquired before maturity—Spiders,
sexual colors of; stridulation by the males—Myriapoda_ . . :
CHAPTER X
SECONDARY SEXUAL OHARAOTERS OF INSEOTS
Diversified structures possessed by the males for seizing the females—~
Differences between the sexes, of which the meaning is not under-
stood—Difference in size between the sexes—Thysanura—Diptera—
Hemiptera—Homoptera, musical powers possessed by tho males
Ce “SAVagO, ImMeEe musical instruments of the males, much diversi-
Curiosity—Imitarion' Sacity 3 colors—Neuroptera, sexual differences
Progressive ImprovemenDusnacity and colors—Coleoptera, colors;
Abstraction, self-conscious#? apparently as an ornament; battles;
in God, spiritual agencies, supamon to both sexes. . " -
344
362
14 CONTENTS
CHAPTER XI
INSECTS, continued—ORDER LEPIDOPTERA (BUTTERFLIES AND MOTHS)
Courtship of butterflies—Battles—Ticking noise—Colors common to both
sexes, or more brilliant in the males—Examples—Not due to the direct
action of the conditions of life—Colors adapted for protection—Colors
of moths—Display—Perceptive powers of the Lepidoptera—Variability
—Causes of the difference in color between the males and females—
Mimicry, female butterflies more brilliantly colored than the males
—Bright colors of caterpillars—Summary and concluding remarks
on the secondary sexual characters of insects—Birds and insects
compared 2 ‘ ‘ : : : 5 , 5 : . 401
CHAPTER XII
SECONDARY SEXUAL CHARACTERS OF FISHES, AMPHIBIANS, AND REPTILES
Fisuzs: Courtship and battles of the males—Larger size of the females
—Males, bright colors and ornamental appendages; other strange
characters—Colors and appendages acquired by the males during the
breeding season alone—Fishes with both sexes brilliantly colored—
Protective colors—The less conspicuous colors 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: Differ-
ences in structure and color between the sexes—Vocal organs. REP-
TILES: Chelonians—Crocodiles—Snakes, colors in some cases protec-
tive—Lizards, battles of—Ornamental appendages—Strange differences
in structure between the sexes—Colors—Sexual differences almost as
great as with birds . : , ‘ 7 5 3 = . . 431
CHAPTER XIII
SECONDARY SEXUAL CHARACTERS OF BIRDS
Sexual differences—Law of battle—Special weapons—Vocal organs—
Instrumental music—Love-antics and dances—Decorations, perma-
nent and seasonal—Double and single annual moults—Display of
ornaments by the males a 3 : i : ‘ . 466
CHAPTER XIV
BIRDS—continued
Choice exerted by the female—Length of courtship—Unpaired birds—
Mental qualities and taste for the beautiful—Preference or antipathy
shown by the female for particular males—Variability of birds—
Variations sometimes abrupt—Laws of variation—Formation of ocelli
—Gradations of character—Case of Peacock, Argus pheasant, and
Urosticte ‘ ‘ a> abe . : ‘ : . : . 522
CONTENTS 15
CHAPTER XV
BIRDS—continued
Discussion as to why the males alone of some species, and both sexes of
others, are brightly colored—On sexually limited inheritance, as ap-
plied to various structures and to brightly colored plumage—Nidifica-
tion in relation to color—Loss of nuptial plumage during the winter 5972
CHAPTER XVI
BIRDS—concluded
The immature plumage in relation to the character of the plumage in both
sexes when adult—Six classes of cases—Sexual differences between
the males of closely allied or representative species—The female as-
suming the characters of the male—Plumage of the young in relation
to the summer and winter plumage of the adulis—On the increase
of beauty in the birds of the world—Protective coloring—Conspicu-
ously colored birds—Novelty appreciated—Summary of the four chap-
ters on birds. : ef e 5 » 3 = . . 598
CHAPTER XVII
" SECONDARY SEXUAL CHARACTERS OF 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 shown by either sex in the pairing of quadrupeds 646
CHAPTER XVIII
SECONDARY SEXUAL CHARACTERS OF MAMMALS—continued
Voice—Remarkable sexual peculiarities in seals—Odor—Development of
the hair—Color of the hair and skin—Anomalous case of the female
being more ornamented than the male—Color and ornaments due to
sexual selection—Color acquired for the sake of protection—Color,
though common to both sexes, often due to sexual selection—On the
disappearance of spots and stripes in adult quadrupeds—On the colors
and ornaments of the Quadrumana—Summary . . ° . 619
16 CONTENTS
PART III
SEXUAL SELECTION IN RELATION TO UAN
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 determin-
ing the marriages of mankind—Attention paid by savages to ornaments
—Their ideas of beauty in woman—The tendency to exaggerate each
natural peculiarity ‘ : ‘ ‘ : . ‘ : .
CHAPTER XX
SECONDARY SEXUAL OHARACTERS OF 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
sexual selection in civilized and savage nations—Conditions favorable
to sexual selection during primeval times—On the manner of action of
sexual selection with mankind—On the women in savage tribes having
some power to choose their husbands—Absence of hair on the body,
and development of the beard—Color of the skin—Summary . °
CHAPTER XXI
GENERAL SUMMARY AND CONOLUSION
Main conclusion that man is descended from some lower form—Manner
of development—Genealogy of man—Intellectual and moral faculties
—Sexual selection—Concluding remarks : ‘ : F .
InpDEx ‘ é é . a é si ° ° A ° .
716
158
THE DESCENT OF MAN
AND
SELECTION IN RELATION 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’’;
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 création indépendante et de
toutes piéces, des espéces,’’ it is manifest that at least
a large number of naturalists must admit that species are
the. modified descendants of other species; and this espe-
cially 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 de-
cide, that I have greatly overrated its importance. Of the
older and honored chiefs in natural science, many unfortu-
nately are still opposed to evolution in every form.
(17).
18 INTRODUCTION
In consequence of the views now adopted by most natu-
ralists, and which will ultimately, as in every other case, be
followed by 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 de-
prived of the weighty arguments derived from the nature
of the affinities which connect together whole groups of
organisms—their geographical distribution in past and pres-
ent times, and their geological succession. The homological
structure, embryological development, and rudimentary or-
gans 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 favor 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, first, 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 labors of a host of eminent men, beginning with
M. Boucher de Perthes; and this is the indispensable 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
anthropomorphous apes; for Prof. Huxley, in the opinion
INTRODUCTION 18
of most competent judges, has conclusively shown that in
every visible character man differs less from the higher apes
than these do from the 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 draught, 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 any degree new.
Lamarck long ago came to this conclusion, which has lately
been maintained by several eminent naturalists and philoso-
phers; for instance, by Wallace, Huxley, Lyell, Vogt, Lub-
bock, Biichner, Rolle, etc.,’ and especially by Hickel. This
last naturalist, besides his great work, ‘‘Generelle Morpholo-
gie’”’ (1866), has recently (1868, with a second edit. in 1870)
published his ‘‘Natiirliche Schdépfungsgeschichte,’’ in which
he fully discusses the genealogy of man. If this work had
appeared before my essay had been written, I should prob-
ably 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. Hickel’s
1 As the works of the first-named authors are so well known, I need not
give the titles; but as those of the latter are less well known in England, I
will give them: ‘‘Sechs Vorlesungen iiber.die Darwin’sche Theorie’’: zweite
Auflage, 1868, von Dr. L. Biichner; translated into French under the title
“‘Confétences sur la Théorie Darwinienne,’’ 1869. ‘‘Der Mensch, im Lichte
der Darwin’sche Lehre,’’ 1865, von Dr. F. Rolle. I will not attempt to give
references to all the authors who have taken the same side of the question,
Thus G. Canestrini has published (‘‘Annuario della Soc. d. Nat.,’’ Modena,
186%, p. 81) a very curious paper on rudimentary characters, as bearing on the
origin of man. Another work has (1869) been published by Dr. Francesco
Barrago, bearing in Italian the title of ‘‘Man, made in the image of God, was
also made in-the image of the ape.”
20 INTRODUCTION
writings, I give his authority in the text; other statements
I leave as they originally stood in my manuscript, occasion-
ally giving in the footnotes references to his works, as &
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 differ-
entiating 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.* Consequently the second part of the present work,
treating of sexual selection, has extended 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 illus-
trious anatomist 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 de-
scended 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 pres-
ent work, I have thought it better to reserve my essay for
separate publication.
? Prof. Hackel was the only author who, at the time when this work first
appeared, had discussed the subject of sexual selection, and had seen its ful
importance, since the publication of the *‘Origin’’; and this he did in a very
able manner in his various works,
PART ONE
THE DESCENT OR ORIGIN OF MAN
a
CHAPTER I
THE EVIDENCE OF THE DESCENT OF MAN FROM
SOME LOWER FORM
Nature of the evidence bearing on the origin of man—Homologous strue-
tures in man and the lower animals—Miscellaneous points of corre-
spondence—Development—Rudimentary structures, muscles, sense-
organs, hair, bones, reproductive organs, etc.—The bearing of these
three great classes of facts on the origin of man
E who wishes to decide whether man is the modified
H descendant of some pre-existing form would prob-
ably first inquire 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. Azain, are the variations the result, as far as our
ignorance permits us to judge, of the same general causes,
and_-are they governed bythe same general laws, as in the
ease of other organisms; for sastance, by correlation, the
inherited effects of use and disusé,cte-? Is man subject
to similar malconformations, the result dretitested develop-
ment, of reduplication of parts, etc., and dow “he display in
any of his anomalies reversion to some former a. 4-2ncient
type of structure? It might also naturally be inquitew
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 distrib-
uted over the world; and how, when crossed, do they react
(21)
22 THE DESCENT OF MAN
on each other in the first and succeeding generations?
And so with many other points.
The inquirer 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 conse-
quently to 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 an-
swered 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 suc-
ceeding 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
mammals. 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 importag¢ stmt tie organs,
follows the same law, as shown by Huxley and other anato-
mists. Bischoff,’ who is a béstile witness, admits that every
chief fissure and fold }7‘the brain of man has its analogy in
that of the oren~phut he adds that at no period of deveiop-
ment do the’ ¢orains perfectly agree; norcould perfect agree-
eerste expected, for otherwise their mental powers would
have been the same. Vulpian* remarks: ‘‘Les différences
aes hirnwindungen des Menschen,” 1868, 8. 96. The conclusions of
this ae as well as thoes of Gratiolet and Aeby, concerning the brain, will
be diseussed by Prof, Huxley in the Appendix alluded to in the Preface to this
aac ee sur la Physiologie,” 1866, p. 890, as quoted by M. Dally, “L’Ordre
des Primates et le Transformisme,”’ 1868, p. 29.
THE DESCENT OR ORIGIN OF MAN 23 ~
réelles qui existent entre l’encéphale de l’homme et celui
des singes supérieurs, sont bien minimes. TI] ne faut pas se
faire d’illusions 4 cet égard. L’homme est bien plus pras
des singes anthropomorphes par les caractéres anatomiques
de son cerveau que ceux-ci ne le sont non-seulement des
autres mammiféres, mais méme de certains quadrumanes,
des guenons et des macaques.’’ But it would be superflu-
ous here to give further details on the correspondence be-
tween man and the higher mammals in the structure of the
brain and all other parts of the body.
It may, however, be worth while to specify a few points,
not directly or obviously connected with structure, by which
this correspondence or relationship is well shown.
Man is liable to receive from the lower animals, and to
communicate to them, certain diseases, as hydrophobia, vari-
ola, the glanders, syphilis, cholera, herpes, etc.;* and this
fact proves the close similarity‘ of their tissues and blood,
both in minute structure and composition, far more plainly
than does their comparison under the best microscope, er
by the aid of the best chemical analysis. Monkeys are lia-
ble to many of the same non-contagious diseases as we are;
thus Rengger,* 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 effect
on them as on us. Many kinds of monkeys have a strong
8 Dr. W. Lauder Lindsay has treated this subject at some length in the
“Journal of Mental Science,’’ July, 1871; and in the ‘‘Edinburgh Veterinary
Review,’’ July, 1858. ;
4 A Reviewer has criticised (‘‘British Quarterly Review,’’ Oct. 1, 1871,
2) what I have here said with much severity and contempt; but, as I do
‘use the term identity, I cannot see that I am greatly in error. There
rs to me a strong analogy between the same infection or contagion pro-
mors the same result, or one closely similar, in two distinct animals, and the -
of two distinet fluids by the same chemical reagent.
*Naturgeschichte der Sdugethiere von Paraguay,’’ 1830, s. 50.
Del
24 THE DESCENT OF MAN
taste for tea, coffee, and spirituous liquors; they will also,
as I have myself seen, smoke tobacco with pleasure. Brehm
asserts that the natives of northeastern Africa catch the wild
baboons by exposing vessels with strong beer, by which they
are made drunk. He has seen some of these animals, which
he kept in confinement, in this state; and he gives a laugh-
able account of their behavior 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.?, An American monkey, an Ateles, after getting
drunk on brandy, would never touch it 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 caus-
ing fatal effects; and is plagued by external parasites, all of
which belong to the same genera or families as those infest-
ing other mammals, and in the case of scabies to the same
species.° Man is subject, like other mammals, birds, and
even insects,® to that mysterious law which causes certain
normal processes, such as gestation, as well as the matura-
tion 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.”
6 The same tastes are common to some animals much lower in the scale,
Mr. A. Nicols informs me that he kept in Queensland, in Australia, three indi-
viduals of the Phaseolarctus cinereus; and that, without having been taught
in any way, they acquired a strong taste for rum, and for smoking tobacco,
7 Brehm, ‘‘Thierleben,’’ B. i. 1864, 8. 75, 86. On the Ateles, s. 105. For
other analogous siatements, see s. 25, 107. os,
‘8 Dr, W. Lauder Lindsay, ‘Edinburgh Vet. Review,’’ July, 1858, p, 3°
® With respect to insects see Dr. Laycock, ‘On a Ger-~al Law =
Periodicity,” “British Association,” 1842. Dr. Maccullock = ~~ ,"0r
American Journal of Science,”’ vol. xvii. p. 305, has seen : an
tertian ague. Hereafter I shall return to this subject. fag
10 T have given the evidence on this head in my ‘‘Var’ Cin
Plants under Domestication,’’ vol. ii, p. 15, and more co ¢ i]
THE DESCENT OR ORIGIN OF MAN 25
The whole process of that most important function, the
reproduction of the species, is strikingly the same in all
mammals, from the first act of courtship by the male,”
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.” 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 tropi-
cal countries the difference is not great, for the orang is
believed not to be adult till the age of from ten to fifteen
years.” Man differs from woman in size, bodily strength,
hairiness, etc., as well as in mind, in the same manner as
do the two sexes of many mammals. So that the corre-
spondence in general structure, in the minute structure of
the tissues, in chemical composition and in constitution,
between man and the higher animals, especially the an-
thropomorphous apes, is extremely 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 em-
bryo itself at a very early period can hardly be distin-
guished from that of other members of the vertebrate king-
dom. At this period the arteries run in arch-like branches,
N “Mares e diversis generibus Quadrumanorum sine dubio dignoscunt femi-
nas humanes a maribus, Primum, credo, odoratu, postea aspectu. Mr. Youatt,
qui diu in Hortis Zoologicis (Bestiariis) medicus animalium erat, vir in rebus
observandis cautus et sagax, hoc mihi certissime probavit, et curatores ejusdem
loci et alii e ministris confirmaverunt. Sir Andrew Smith et Brehm notabant
idem in Cynocephalo. Mlustrissimus Cuvier etiam narrat multa de hae re, qué
ut opinor, nihil turpius potest indicari inter omnia hominibus et Quadrumanis
communia, Narrat enim Cynocephalum quendam in furorem incidere aspectu
feminarum aliquarum, sed nequaquam accendi tanto furore ab omnibus. Sem-
per eligebat juniores, et dignoscebat in turb4, et advocabat voce gestfique.””
2 This remark is made with respect to Cynocephalus and the anthropo-
morphous apes by Geoffroy Saint-Hilaire and F. Cuvier, ‘Hist. Nat. des
Mammiféres,”? tom. i. 1824.
18 Huxley, ‘“‘Man’s Place in Nature,’ 1863, p. 84.
Descent—Vot. L—2
26 THE DESCENT OF MAN
as if to carry the blood to branchie 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 posi-
tion. Ata somewhat later period, when the extremities are
developed, ‘‘the feet of lizards and mammals,”’ as the illus- —
trious 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,” ‘‘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 de-
velopments 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.’*
After the foregoing statements made by such high au-
thorities, it would be superfluous on my part to give a num-
ber of borrowed details, showing 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 ves-
sel; the excreta are voided through a cloacal passage; and
the os coceyx projects like a true tail, ‘‘extending consider-
ably beyond the rudimentary legs.’’'* In the embryos of all
air-breathing vertebrates, certain glands, called the corpora
4 ‘“Man’s Place in Nature,’’ 1863, p. 67.
1% The human embryo (upper fig.) is from Ecker, ‘‘Icones Phys.,’? 1851<
1859, tab. xxx. fig. 2. This embryo was ten lines in length, so that the
drawing is much magnified. The embryo of the dog is from Bischoff, ‘‘Ent-
wicklungsgeschichte des Hunde-EHies,’’ 1845, tab. xi. fig. 42 B. This drawing
is ve times magnified, the embryo being twenty-five days old. The internal
viscera have been omitted, and the uterine appendages in both drawings re-
moved. I was directed to these figures by Prof. Huxley, from whose work,
‘‘Man’s Place in Nature,’’ the idea of giving them was taken. Hackel has also
given analogous drawings in his ‘‘Sch6pfungsgeschichte.”’
16 Prof. Wyman in “‘Proc. of American Acad. of Sciences,’? vol, iv., 1860,
p. 1%.
THE DESCENT OR ORIGIN OF MAN 27
Wolffiana, correspond with and act like the kidneys of ma-
ture fishes." Even at a later embryonic period, some strik-
ing resemblances between man and the lower animals may
Fia. 1.—Upper figure human embryo, from Ecker. Lower figure that of a dog,
from Bischoff. a. Fore-brain, cerebral hemispheres, etc. 6. Mid-brain, corpora
uadrigemina, c. Hind-brain, cerebellum, medulla oblongata. d. Bye. e. Har. f.
irst visceral arch. g. Second visceral arch. H. Vertebral columns and muscles
in process of development. 7, Anterior extremities. K. Posterior extremities, L.
Tad or 08 Coccyx.
17 Owen, “Anatomy of Vertebrates,”’ vol. i. p. 533.
‘
28 THE DESCENT OF MAN
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..° The great toe, as Prof. Owen remarks,”
“which forms the fulerum 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” 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 permanent condition of this part in the quadru-
mana.’’ I will conclude with a quotation from Huxley,”
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 immediatély below
him in the scale; without a doubt in these respects, he is
far nearer to apes than the apes are to the dog.”’
Rudiments.—This subject, though not intrinsically more
important than the two last, will for several reasons be
treated here more fully.” Not one of the higher animals
can be named which does not bear some part in a rudi-
mentary condition; and man forms no exception to the rule.
Rudimentary organs must be distinguished from those that
are nascent; though in some cases the distinction is not
easy. The former are either absolutely useless, such as
the mammz of male quadrupeds, or the incisor teeth of
ruminants which never cut through the gums; or they are
418 “Die Grosshirnwindungen des Menschen,’’ 1868, s. 95,
19 ‘Anatomy of Vertebrates,’’ vol. i. p. 553.
20 ‘Proc, Soc. Nat. Hist.’? Boston, 1863, vol. ix. p, 185.
21 ‘*Man’s Place in Nature,”’ p. 65.
22 T had written a rough copy of this chapter before reading a valuable paper,
“‘Caratteri rudimentali in ordine all origine del uomo”’ (‘‘Annuario della Soc. d,
Nat.,’? Modena, 1867, p. 81), by G. Canestrini, to which paper I am consid.
erably indebted. Hackel has given admirable discussions on this whole
subject, under the title of Dysteleology, in his ‘“‘Generelle Morphologie,’’ and
*‘Schépfungsgeschichte. ”
THE DESCENT OR ORIGIN OF MAN ap
of such slight service to their present possessors that we
can hardly suppose that they were developed under the
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 be-
come wholly suppressed. When this occurs, they are never-
theless liable to occasional reappearance through reversion
—a circumstance well worthy of attention.
The chief agents in causing organs to become rudimen-
tary seem to have been disuse at that period of life when the
organ is chiefly used (and this is generally during 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 press-
ure, 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 rudi-
ments, 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 is probably often
aided through the two principles of compensation and econ-
omy of growth; but the later stages of reduction, after dis-
use has done all that can fairly be attributed to it, and when
‘tue coving to be effected by the economy of growth would
be very smui:,” are difficult to understand. The final and
complete suppres.‘on of a part, already useless and much
reduced in size, in which case neither compensation nor
33 Some good criticisms on this subject have been given by Messrs. Murie
and Mivart, in ‘“‘Transact. Zoolog. Soc, ’’ 1869, vol. vii, p. 92.
30 THE DESCENT OF MAN
economy can come into play, is perhaps intelligible by the
aid of the hypothesis of pangenesis. But as the whole sub-
ject of rudimentary organs has been discussed and illustrated
in my former works,* I need here say no more on this head.
Rudiments of various muscles have been observed in
many parts of the human body, and not a few muscles
which are 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 pan-
niculus carnosus. Remnants 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 Edin-
burgh, has occasionally detected, as he informs me, muscu-
lar fasciculi in five different situations, namely in the axille
near the scapula, ete., all of which must be referred to the
system of the panniculus. He has also shown” that the
musculus sternalis or sternalis brutorum, which is not an ex-
tension of the rectus abdominalis, but is closely allied to the
panniculus, occurred in the proportion of about three per
cent in upward of 600 bodies: he adds, that this muscle
affords ‘‘an excellent illustration of the statement that oc-
casional and rudimentary structures are especially liable
to variation in arrangement.”’
Some few persons have the power of contracting the
superficial 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
4 ‘Variation of Animals and Plants under Domestication,’’ vol. *
and 397%. See also ‘Origin of Species,”’ 5th edit. p. 535.
2 For instance M. Richard (‘Annales des Sciences Natading a valuable paper,
1852, tom. xviii. p. 18) describes and figures rudimer.(‘‘Annuario della Soc. d,
“muscle pédieux de la main,’? which he says is sow Which paper I am consid-
Another muscle, called “‘le tibial postérieur,’”’ ig-¢ discussions on this whole
hand, but appears from time to time in a more “Generelle Morphologie,” and
86 Prof. W. Turner, ‘‘Proc. Royal Soc. Edi
THE DESCENT OR ORIGIN OF MAN 31
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 per-
forming 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-mentioned
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 trans-
mission 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.”
The extrinsic muscles which serve to move the external
ear, and the intrinsic muscles which move the different parts,
are in a rudimentary condition in man, and they all belong
to the system 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 forward; other men can draw
it upward; another who could draw it backward; 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 toward 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,
-yné"ew thus perceive the direction of danger; but I have
be very smaim sufficient evidence, of a man who possessed
complete suppress». which might be of use to him. The
reduced in size, in
> Emotions in Man and Animals,’? 1872, p. 144.
38 Some good criticisms on Annuario della Soe. dei Naturalisti, 2 Modena,
and Mivart, in ‘Transact. Zoolog.
32 THE DESCENT OF MAN
whole external shell may be considered a rudiment, together
with the various folds and prominences (helix and anti-
helix, tragus and anti-tragus, etc.) which in the lower ani-
mals strengthen and support the ear when erect, without
adding much to its weight. Some authors, however, sup-
pose that the cartilage of the shell serves to transmit vibra-
tions to the acoustic nerve; but Mr. Toynbee,” after collect-
ing all the known evidence on this head, concludes that the
external shell is of no distinct use. The ears of the chim-
panzee and orang are curiously like those of man, and the
proper muscles are likewise but very slightly developed.”
Iam also assured by the keepers in the Zoological Gardens
that these animals never move or erect their cars; 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 compensated by the freedom with
which they can move the head in a horizontal plane, so as
to catch sounds from all directions. It has been asserted
that the ear of man alone possesses a lobule; but ‘‘a rudi-
ment of it is found in the gorilla’’;* and, as I hear from
Prof. Preyer, it is not rarely absent in the negro.
2% “The Diseases of the Ear,’’ by J. Toynbee, F.R.S., 1860, p. 12. A dis-
tinguished physiologist, Prof. Preyer, informs me that he had lately been ex-
perimenting on the function of the shell of the ear, and has come to nearly the
same conclusion as that given here.
30 Prof. A. Macalister, ‘‘Annals and Mag. of Nat. History,”’ vol. vii.,
1871, p. 342.
31 Mr, St. George Mivart, ‘‘Elementary Anatomy,’ 1873, p. 396,
THE DESCENT OR ORIGIN OF MAN 33
The celebrated sculptor, Mr. Woolner, informs me of one
little peculiarity in the external ear, which he has often ob-
served both in men and women, and of which he perceived
the full significance. His attention was first called to the
subject while 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 subsequently 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 wo-
man. Mr. Woolner made an exact model of one such case,
and sent me the accompanying draw-
ing (Fig. 2). These points not only
project inward toward the centre of
the ear, but often a little outward 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 con-
fined to mankind, for I observed as deawa ty Me Woonee
a. The projecting point
case in one of the spider-monkeys
(Ateles beelzebuth) in our Zoological Gardens; and Dr. HE. Ray
Lankester informs me of another case in a chimpanzee in the
gardens at Hamburg. The helix obviously consists of the
extreme margin of the ear folded inward; and this folding
appears to be in some manner connected with the whole ex-
ternal ear being permanently pressed backward. In many
monkeys, which do not stand high in the order, as baboons
and some species of Macacus,” the upper portion of the ear
is slightly pointed, and the margin is not at all folded in-
32 See also some remarks, and the drawings of the ears of the Lemuroidea,
= Messrs, Murie and Mivart’s excellent paper in ‘‘Transact. Abas Soc.,’’ vol
, 1869, pp. 6 and 90.
84 THE DESCENT OF MAN
ward; but if the margin were to be thus folded, a slight
. point would necessarily project inward toward the centre,
and probably a little outward from the plane of the ear: and
this I believe to be their origin in many cases. On the other
hand, Prof. L. Meyer, in an able paper recently published,**
maintains that the whole case is one of mere variability; and
that the projections are not real ones, but are due to the in-
ternal cartilage on each side of the points not having been
fully developed. Iam 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 microcephalous
idiot, on which there is a projection on the outside 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 of
their occurrence, and from the general correspondence in
position with that of the tip of a pointed ear. In one case,
of 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 inward, but is pointed, so that it closely resem-
bles the pointed ear of an ordinary quadruped in outline.
In one of these cases, which was that of a young child, the
father compared the ear with the drawing which I have
given of the ear of a monkey, the Cynopithecus niger, and
says that their outlines are closely similar. If, in these two
33 Ueber das Darwin’sche Spitzohr, Archiv fir Path. Anat. und Phys.,
1871, p. 486.
% ‘The Expression of the Emotions,” p. 136.
THE DESCENT OR ORIGIN OF MAN 35
eases, the margin had been folded inward 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 inward—in one of them, how-
ever, very narrowly. The following woodcut (No. 8) is
an accurate copy of a photograph of the foetus of an orang
(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 re-
Fie. 3.—Foetus of an Orang. Exact copy of a photograph, showing the form
of the ear at this early age.
semblance 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 rise to a point
projecting inward. On the whole, it still seems to me prob-
able that the points in question are in some cases, both in
man and apes, vestiges of a former condition.
The nictitating membrane, or third eyelid, with its ac-
cessory 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 .
36 THE DESCENT OF MAN
certain fishes, as in sharks. It is fairly well developed
in the two lower divisions of the mammalian series, namely,
in the monotremata and marsupials, and in some few of the
higher mammals, as in the walrus. But in man, the quad-
rumana, and most other mammals, it exists, as is admitted
by all anatomists, as a mere rudiment, called the semilunar
fold.**
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 find-
. : ~~ . . .
ing 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-colored races of men,
in whom it is much more highly developed than in the white
and civilized races.** Nevertheless it does not warn them of
danger, nor guide them to their food; nor does it prevent
the Eskimos from sleeping in the most fetid atmosphere,
nor many savages from eating half-putrid meat. * In Euro-
peans the power differs greatly in different individuals, as
Iam assured by an eminent naturalist who possesses this
sense highly developed, and who has attended to the sub-
ject. Those who believe in the principle of gradual evolu-
tion 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
25 Miiller’s ‘‘Hlements of Physiology,’’ Eng. translat., 1842, vol. ii. p. 1117.
Owen, ‘‘Anatomy of Vertebrates,’’ vol. iii. p. 260; ibid. on the Walrus, ‘‘Proe.
Zoolog. Soc.,’? November 8, 1854. See also R. Knox, ‘‘Great Artists and
Anatomists,’’ p. 106. This rudiment apparently is somewhat larger in Negroes
anid Australians than in Europeans; see Carl Vogt, ‘‘Lectures on Man,’’ Eng.
translat. p. 129.
36 The account given by Humboldt of the power of smell possessed by the
natives of South America is well known, and has been confirmed by others.
M. Houzeau (‘Etudes sur les Facultés Mentales,”’ ete., tom. i., 1872, p. 91)
asserts that he repeatedly made experiments, and proved that Negroes and
Indians could recognize persons in the dark by their odor. Dr. W. Ogle has
made some curious observations on the connection between the power of smell
and the coloring matter of the mucous membrane of the olfactory region, as
well as of the skin of the body. I have, therefore, spoken in the text of the
dark-colored races having a finer sense of smell than the white races. See his
paper, ‘‘Medico-Chirurgical Transactions,’’ London, vol. liii., 1870, p. 276.
THE DESCENT OR ORIGIN OF MAN 37
rudimentary condition, from some early progenitor, to whom
it was highly serviceable, and by whom it was continually
used. In those animals which have this sense highly devel-
oped, such as dogs and horses, the recollection of persons
and of places is strongly associated with their odor; and we
can thus perhaps understand how it is, as Dr. Maudsley has
truly remarked,* that the sense of smell in man ‘‘is singu-
larly 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, while in others they bear thick tufts of
hair.** There can be little doubt that the hairs thus scat-
tered 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-
colored hairs on the limbs and other parts of the body occa-
sionally become developed into ‘‘thick-set, long, and rather
coarse, dark hairs,’’? when abnormally nourished near old-
standing inflamed surfaces. *
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 pecu-
liarity 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 consider-
able length rising from the naked skin above the eyes, and
corresponding to our eyebrows; similar long hairs project
31 ‘The Physiology and Pathology of Mind,”’ 2d edit., 1868, p. 134.
38 Eschricht, Ueber die Richtung der Haare am menschlichen Kérper,
‘‘Miller’s Archiv fir Anat. und Phys.,’? 1837, s. 47. I shall often have to
refer to this very curious paper. ,
39 Paget, ‘‘Lectures on Surgical Pathology, 7? 1853, vol. i. p. 71.
38 THE DESCENT OF MAN
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 mustache of this kind was observed by Eschricht* on a
female foetus; but this is not so surprising a circumstance
as it may at first appear, for the two sexes generally resem-
ble each other in all external characters during an early
period of growth. The direction and arrangement of the
hairs on all parts of the foetal 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 in-
ferior surfaces of all four extremities in most of the lower
animals. As this can hardly be an accidental coincidence,
the woolly covering 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 abnormal
condition of the teeth." Prof. Alex. Brandt informs me
that he has compared the hair from the face of a man thus
characterized, aged thirty-five, with the lanugo of a feetus,
and finds it quite similar in texture; therefore, as he re-
marks, the case may be attributed to an arrest of develop-
ment in the hair, together with its continued growth. Many
delicate children, as I have been assured by a surgeon to
a hospital for children, have their backs covered by rather
40 Eschricht, ibid., s. 40, 4%.
4 See my “Variation of Animals and Plants under Domestication,” vol. ii,
p. 327. Prof. Alex. Brandt has recently sent me an additional case of a father
and son, born in Russia, with these peculiarities. I have received drawings
of both from Paris.
THE DESCENT OR ORIGIN OF MAN 39
long silky hairs; and such cases probably come under the
same head.
It appears as if the posterior molar or wisdom teeth were
tending to become rudimentary in the more civilized races of
man. These teeth are rather smaller than the other molars,
as is likewise the case with the corresponding teeth in the
chimpanzee 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 struc-
ture and in the period of their development, than the other
teeth.*? 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.“
Prof. Schaaffhausen accounts for this difference between
the races by ‘‘the posterior dental portion of the jaw being
always shortened’’ in those that are civilized,** and this
shortening may, I presume, be attributed to civilized men
habitually feeding on soft, cooked food, and thus using their
jaws less. Iam 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 nor-
mal number.**
With respect to the alimentary canal, I have met with
an account of only a single rudiment, namely, the vermi-
form appendage of the cecum. The cecum is a branch or
4 Dr, Webb, ‘“‘Teeth in Man and the Anthropoid Apes,’’ as quoted by Dr.
C. Carter Blake in *‘Anthropological Review,”’ July, 1867, p. 299.
4# Owen, ‘‘Anatomy of Vertebrates,’’ vol. iii. pp. 320, 321, 325,
4 “On the Primitive Form of the Skull.”’ Eng. translat. in ‘‘Anthropologi-
cal Review,’’ Oct., 1868, p. 426.
4 Prof. Mantegazza writes to me from Florence, that he has lately been
studying the last molar teeth in the different races of man, and has come to the
same conclusion as that given in my text, viz., that in the higher or civilized
races they are on the road toward atrophy or elimination.
40 THE DESCENT OF MAN
diverticulum of the intestine, ending in.a cul-de-sac, and is
extremely long in many of the lower vegetable-feeding mam-
mals. In the marsupial koala itis actually more than thrice
as long as the whole body.** It is sometimes produced
into a long, gradually tapering point, and is sometimes con-
stricted in parts. It appears as if, in consequence of changed
diet or habits, the cecum had become much 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’ has collected of its vari-
ability in man. It is occasionally quite absent, 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 orang
this appendage is long and convoluted; in man it arises
from the end of the short cecum, 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 some.
times 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 inflammation.”
In some of the lower Quadrumana, in the Lemuride and
Carnivora, as well as in many marsupials, there is a passage
near the lower end of the humerus, called the supra-condy-
loid foramen, through which the great nerve of the forelimb
and often the great artery pass. Now in the humerus of
man there is generally a trace of this passage, which is some-
times fairly well developed, being formed by a depending
hook-like process of bone, completed by a band of ligament.
Dr. Struthers,“ who has closely attended to the subject, has
46 Owen, ‘‘Anatomy of Vertebrates,’’ vol. iii. pp. 416, 434, 441,
41 *‘Annuario della Soc. d. Nat.,’? Modena, 1867, p. 94.
48 M. C. Martins (‘‘De l’Unité Organique,’’ in ‘‘Revue des Deux Mondes,”?
sune 15, 1862, p. 16), and Hackel (‘‘Generelle Morphologie,”’ B. ii. s. 278), have
both remarked on the singular fact of this rudiment sometimes causing death,
49 With respect to inheritance, see Dr. Struthers in the ‘‘Lancet,’’? Feb. 15,
1873, and another important paper, ibid., Jan. 24, 1863, p. 83. Dr. Knox,
as I am informed, was the first anatomist who drew attention to this peculiar
THE DESCENT OR ORIGIN OF MAN 41
now shown 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 present, 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 Quadru-
mana it is absent.
There is another foramen or perforation in the humerus,
occasionally present in man, which may be called the inter-
condyloid. This occurs, but not constantly, in various an-
thropoid and other apes, * 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® 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 ‘Cimetiére du Sud,’ at Paris; and in the
Grotto of Orrony, the contents of which are referred to
the Bronze period, as mary as eight humeri out of thirty-
two were perforated; but this extraordinary 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 Reindeer period; while 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
structure in man; see his ‘‘Great Artists and Anatomists,’’ p. 63. See also an
important memoir on this process by Dr. Gruber, in the ‘‘Bulletin de lAcad.
Imp. de St. Petersburg,”’ tom. xii., 1867, p. 448.
50 Mr, St. George Mivart, ‘‘Transact. Phil. Soc.,’’ 1867, p. 310.
51 “On the Caves of Gibraltar,’ ‘“Transact. Internat. Congress of Prehist.
Arch.’ Third Session, 1869, p. 159. Prof. Wyman has lately shown (Fourth
Annual Report, Peabody Museum, 1871, p. 20) that this perforation is present
in thirty-one per cent of some human remains from ancient mounds in the West-
ern United States, and in Florida It frequently occurs in the negro.
42 THE DESCENT OF MAN
cent in the same condition in bones from Vauréal. Nor
should it be left unnoticed that M. Pruner-Bey states that
this condition 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 ver-
tebre 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 ahumanembryo. Hven after birth it has been known, in
certain rare and anomalous cases,* to form a small external
rudiment ofa tail. The os coccyx is short, usually includ-
ing only four vertebre, all anchylosed together: and these
are in a rudimentary condition, for they consist, with the
exception of the basal one, of the centrum alone.* 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 downward
as the last dorsal or first lumbar vertebra; but a thread-like
structure (the filum terminale) 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
5 Quatrefages has lately collected the evidence on this subject. ‘‘Revue
des Cours Scientifiques,’’ 1867-68, p. 625. In 1840 Fleischmann exhibited a
human foetus bearing a free tail, which, as is not always the case, included
vertebral bodies; and this tail was critically examined by the many anatomists
present at the meeting of naturalists at Erlangen (see Marshall in Niederlind-
ischen Archiv fiir Zoologie, December, 1871).
53 Owen ‘‘On the Nature of Limbs,’’ 1849, p. 114.
THE DESCENT OR ORIGIN OF MAN 43
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
inclosed within a bony canal. The following fact, for which
I am also indebted to Prof. Turner, shows how closely the
oS coccyx corresponds with the true tail in the lower ani-
mals: 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 discov-
ery led Krause and Meyer to examine the tail of a monkey
(Macacus) and of a cat, in both of which they found a simi-
larly convoluted body, though not at the extremity.
The reproductive system offers various rudimentary
structures; 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. Never-
theless, the occurrence of such rudiments is as difficult to
explain, on the belief of the separate creation of each spe-
cies, as in the foregoing cases. Hereafter I shall have to
recur to these rudiments, and shall show that their presence
generally depends merely on inheritance, 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. Itis well known, that in the males of all mam-
mals, including man, rudimentary mammz 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 shown by their occasional sym-
pathetic enlargement in both during an attack of the 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 connected
passage. It is impossible to read Leuckart’s able descrip-
tion of this organ, and his reasoning, without admitting the
44. THE DESCENT OF MAN
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.“ Some other rudimentary structures belonging
to the reproductive system might have been here adduced.”
The bearing of the three great classes of facts now given
is unmistakable. 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 of a horse, the flipper
of a seal, the wing of a bat, etc., is utterly inexplicable.”
It is no scientific explanation to assert that they have all
been formed on the same ideal plan. With respect to de-
velopment, we can clearly understand, on the principle of
variations supervening at a rather late embryonic period,
and being inherited at a corresponding period, how it is
54 Leuckart, in Todd’s ‘‘Cyclop. of Anat.,’’ 1849-52, vol. iv. p. 1415, In
man this organ is only from three to six lines in length, but, like so many other
rudimentary parts, it is variable in development as well as in other characters.
55 See, on this subject, Owen, ‘‘Anatomy of Vertebrates,”’ vol. iii. pp. 675,
676, 706.
56 Prof. Bianconi, in a recently published work, illustrated by admirable
engravings (‘La Théorie Darwinienne et la Création dite indépendante,’’ 1874),
endeavors to show that homological structures, in the above and other cases,
can be fully explained on mechanical principles, in accordance with their uses,
No one has shown so well how admirably such structures are adapted for their
final purpose; and this adaptation can, as I believe, be explained through natu-
ral selection. In considering the wing of a bat, he brings forward (p. 218) what
appears to me (to use Auguste Comte’s words) a mere metaphysical principle,
namely, the preservation ‘‘in its integrity of the mammalian nature of the ani-
mal.’? In only a few cases does he discuss rudiments, and then only those
parts which are partially rudimentary, such as the little hoofs of the pig and
ox, which do not touch the ground; these he shows clearly to be of service to
the animal. Itis unfortunate that he did not consider such cases as the minute
teeth, which never cut through the jaw in the ox, or the mamme of male quad-
rupeds, or the wings of certain beetles, existing under the soldered wing-covers,
or the vestiges of the pistil and stamens in various flowers, and many other
such cases. Although I greatly admire Prof. Bianconi’s work, yet the belief
now held by most naturalists seems to me left unshaken, that homological
structures are inexplicable on the principle of mere adaptation.
THE DESCENT OR ORIGIN OF MAN 45
that the embryos of wonderfully different forms should still
retain, more 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, etc., can at first hardly be distinguished from
each other. In order to understand the existence of rudi-
mentary 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
indicated.
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 of 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 ani-
mals around us, is a mere snare laid to entrap our judg-
ment. 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 geological 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 wonder-
ful that naturalists, who were well acquainted with the com-
parative structure and development of man and other mam-
mals, should have believed that each was the work of a
separate act of creation.
46 THE DESCENT OF MAN
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—Hffects of the increased use and dis-
use 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 struc-
ture—The causes which have led to his becoming erect—Consequent
changes of structure—Decreuase in size of the canine teeth—Increased
size and altered shape of the skull—Nakedness—Absence of a tail
—Defenceless condition of man
T IS manifest that man is now subject to much varia-
bility. No two individuals of the same race are quite
alike. Wemay 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.’ Although in some quarters of the world an elon-
gated 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 homoge-
neous in blood, customs, and language as any in existence”’
—and even with the inhabitants of so confined an area as
the Sandwich Islands.?- An eminent dentist assures me that
1 “Investigations in Military and Anthropolog. Statistics of American Sol-
diers,’’ by B. A. Gould, 1869, p. 256.
2 With respect to the ‘‘Cranial Forms of the American Aborigines,*’ see Dr,
Aitken Meigs in ‘‘Proc. Acad. Nat. Sci.,’’ Philadelphia, May, 1868. On the
Australians, see Huxley, in Lyell’s “‘Antiquity of Man,’’ 1863, p. 8%. On
the Sandwich Islanders, Prof. J. Wyman, ‘‘Observations on Crania,’’ Boston,
1868, p. 18.
THE DESCENT OR ORIGIN OF MAN 47
there is nearly as much diversity in the teeth as in the fea-
tures. The chief arteries so frequently run in abnormal
courses that it has been found useful for surgical purposes
to calculate from 1,040 corpses how often each course pre-
vails.? The muscles are eminently variable: thus those of
the foot were found by Prof. Turner* not to be strictly alike
in any two out of fifty bodies; and in some the deviations
were considerable. He adds, that the power of performing
the appropriate movements must have been modified in
accordance with the several deviations. Mr. J. Wood has
recorded® 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 want-
ing in departures from the standard descriptions of the mus-
cular system given in anatomical 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*® no less than
twenty distinct variations in the palmeris accessorius.
The famous old anatomist, Wolff,’ insists that the inter-
nal viscera are more variable than the external parts: Nulla
particula est que non aliter et aliter in aliis se habeat homini-
bus. 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, etc., as of the
human face divine, sounds 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.
3 “Anatomy of the Arteries,’? by R. Quain. Preface, vol. i., 1844.
4 “Transact. Royal Soc. Edinburgh,’’ vol. xxiv. pp. 175, 189.
5 **Proc, Royal Soc.,’? 186%, p. 544; also 1868, pp. 483, 624. There is a
» previcas paper, 1866, p. 229.
6 “*Proc. R. Irish Academy,’’ vol. x., 1868, p. 141.
7 “Act, Acad. St. Petersburg,’’ 1778, part ii. p. 217.
48 THE DESCENT OF MAN
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 his own peculiar
disposition and temper: he mentions 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. Reng-
ger, also, insists on the diversity in the various mental char-
acters 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 manner in which they have been
treated or educated.°
XI have elsewhere’ so fully discussed the subject of Inheri-
tance, that I need here add hardly anything. A greater
number of facts have been collected with respect to the
transmission of the most trifling, as well as of the most
important, characters in man than in any of the lower ani-
mals; though the facts are copious enough with respect to
the latter. So in regard to mental qualities, their transmis-
sion is manifest in our dogs, horses, and other domestic ani-
mals. Besides special tastes and habits, general intelligence,
courage, bad and good temper, etc., are certainly transmitted.
With man we see similar facts in almost every family; and
we now know, through the admirable labors of Mr. Galton,*
that genius, which implies a wonderfully complex combina-
tion of high faculties, tends to be inherited; and on the
other hand, it is too certain that insanity and deteriorated
mental powers likewise run in families. X
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 gen-
8 Brehm, ‘‘Thierleben,’’ B. 1. 3. 58, 87. Rengger, ‘‘Sdugethiere von Para-
guay,’’ s. 57.
9 “Variation of Animals and Plants under Domestication,”’ vol. ii. chap. xii.
10 ‘‘Hereditary Genius: an Inquiry into its Laws and Consequences,’’ 1869,
THE DESCENT OR ORIGIN OF MAN 49
erations. 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 civilized 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.* It is, nevertheless, an error to speak of man, even
if we look only to the conditions to which he has been ex-
posed, as ‘‘far more domesticated’’ * 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 completely subjugated by other
men, as that certain individuals should be preserved, and
thus unconsciously selected, from somehow excelling in
utility to their masters. Nor have certain male and female
individuals been intentionally picked out and matched, ex-
cept in the well-known case of the Prussian grenadiers; and
in this case man obeyed, as might have been expected, 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 selection
was followed, for it was enacted that all children should be
11 Mr. Bates remarks a Naturalist on the Amazons,”’ 1863, vol. ii. p.
159), with respect to the Indians of the same South American tribe, ‘‘no two
of them were at all similar in the shape of the head; one man had an oval vis-
age with fine features, and another was quite Mongolian in breadth and promi-
nence of cheek, spread of nostrils, and obliquity of eyes.”
12 Blumenbach, ‘‘Treatises on Anthropolog.,”’ Eng, translat., 1865, p. 205.
Descent—Vot. L—3
50 THE DESCENT OF MAN
examined shortly after birth; the well-formed and vigorous
being preserved, the others left to perish.”
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 domesti-
cated animals.
Not only does variability appear to be 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 de-
tail by Godron and Quatrefages that I need here only refer
to their works.“ ¥Monstrosities, which graduate into slight
variations, are likewise so similar in man and the lower ani-
mals, that the same classification and the same terms can
18 Mitford’s “‘History of Greece,’? vol. i. p. 282. It appears also from a
passage in Xenophon’s ‘‘Memorabilia,’’ B. ii. 4 (to which my attention has been
called by the Rev. J. N. Hoare), that it was a well recognized principle with
the Greeks, that men ought to select their wives with a view to the health and
vigor of their children. The Grecian poet, Theognis, who lived 550 B.c., clearly
saw how important selection, if carefully applied, would be for the improvement
of mankind. He saw, likewise, that wealth often checks the proper action of
sexual selection. He thus writes:
‘‘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! the cause is plaix,
And to lament the consequence is vain.”’
—The Works of J. Hookham Frere, vol. ii., 1872, p. 334.
14 Godron, ‘‘De l’Espéce,’’ 1859, tom. ii. livre 3. Quatrefages, ‘‘Unité
de l’Espéce Humaine,’’ 1861. Also Lectures on Anthropology, given in the
“Revue des Cours Scientifiques,’’ 1866-68.
THE DESCENT OR ORIGIN OF MAN 51
be used for both, as has been shown by Isidore Geoffroy
St.-Hilaire."* 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 di-
rect 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;’* but several are so important
that they must be treated at considerable length.
The direct and definite action of changed conditions. —This
is a most perplexing subject. It cannot be denied that
changed conditions produce some, and occasionally a con-
siderable 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 favor of this conclusion, 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,
15 ‘Hist. Gén. et Part, des Anomalies de l’Organisation,’’ in three volumes,
tom. i. 1832. :
16 T have fully discussed these laws in my ‘‘Variation of Animals and Plants
under Domestication,’’ vol. ii. chaps. xxii, and xxiii. M. J. P. Durand has
lately (1868) published a valuable essay, ‘‘De 1’Influence des Milieux,” ete,
He lays much stress, in the case of plants, on the nature of the soil.
52 THE DESCENT OF MAN
by which the whole organization is rendered in some degree
plastic.
In the United States, above one million soldiers, who
served in the late war, were measured, and the States in
which they were born and reared were recorded.” 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 influ-
ence on the stature.’’ For 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
shown ‘‘by the great difference between the statures of
soldiers and sailors at the ages of seventeen and eighteen
years.’’¥ Mr. B. A. Gould endeavored 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
‘nm any controlling degree’’ to the abundance or the need
of the comforts of life. This latter conclusion is directly
opposed to that arrived at by Villermé, 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 low barren coral islands of the same ocean," or again
between the Fuegians on the eastern and western shores
of their country, where the means of subsistence are very
different, it is scarcely possible to avoid the conclusion that
1 ‘Investigations in Military and Anthrop. Statistics,’ etc., 1869, by B. A,
Gould, pp. 93, 107, 126, 131, 134.
18 For the Polynesians, see Prichard’s ‘‘Physical Hist. of Mankind,” vol.
v., 1847, pp. 145, 283. Also Godron, ‘“De lEspéce,’’ tom. ii. p. 289. There
is also a remarkable difference in appearance between the closely allied Hindus
inhabiting the Upper Ganges and Bengal; see Elphinstone’s ‘‘History of India,”
vol. i, p. 324.
THE DESCENT OR ORIGIN OF MAN BB
better food and greater comfort do intluence stature. But
the preceding statements show 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 cer-
tain occupations 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 vigor.” ’°
Whether external conditions produce any other direct
effect on man is not known. It might have been expected
that differences of climate would have had a marked influ-
ence, inasmuch as the lungs and kidneys are brought into
activity under a low temperature, and the liver and skin
under a high one.” It was formerly thought that the color
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 dur-
ing many ages. But this subject will be more properly dis-
cussed when we treat of the different races of mankind.
With our domestic animals there are grounds for believ-
ing 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.
Liffects of the increased Use and Disuse of Parts.—It is
well known that use strengthens the muscles in the individ-
ual, 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
19 “Memoirs, Authropolog. Soc.,’’ vol. iii., 1867-69, pp. 561, 565, 567.
® Dr. Brakenridge, ‘‘Theory of Diathesis,”’ ‘‘Medical Times,”’ June 19, and
July 17, 1869.
54 THE DESCENT OF MAN
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.” Different
occupations, habitually followed, lead to changed propor-
tions in various parts of the body. Thus it was ascertained
by the United States Commission” that the legs of the sail-
ors 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; while their arms were shorter by 1.09
of an inch, and therefore, out of proportion, shorter in rela-
tion to their Jesser 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, while the circum-
ference of the chest, waist and hips is less, than in soldiers,
Whether the several foregoing modifications would be-
come hereditary, if the same habits of life were followed
during many generations, is not known, but it is probable.
Rengger® attributes the thin legs and thick arms of the
Payaguas Indians to successive generations having passed
nearly their whole lives in canoes, with their lower extremi-
ties motionless. Other writers have come to a similar con-
clusion in analogous cases. XAccording to Cranz,™ who lived
for a long time with the Eskimos, ‘‘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-cateher 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 laborers are at birth larger than
21 T have given authorities for these several statements in my ‘‘Variation
of Animals under Domestication,” vol. ii. pp. 297-300. Dr. Jaeger, ‘“‘Ueber
das Langenwachsthum der Knochen,”’ ‘‘Jenaischen Zeitschrift,’ B, v. Heft i,
22 “Tnvestigations,’’ ete. By B, A. Gould, 1869, p. 288.
% “Sdugethiere von Paraguay,”’ 1830, s. 4.
% “History of Greenland,’’ Eng. translat., 1767, vol. i. p. 230.
THE DESCENT OR ORIGIN OF MAN 55
those of the gentry.* From the correlation which exists,
at least in some cases,** between the development of the ex-
tremities and of the jaws, it is possible that in those classes
which do not labor much with their hands and feet, the jaws
would be reduced in size from this cause. That they are
generally smaller in refined and civilized 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;** and it can hardly be doubted that this
is due to the inherited effects of pressure during a long
series of generations.
Tt is familiar to every one that watchmakers and engravers
are liable to be short-sighted, while men living much out of
‘doors, and especially savages, are generally long-sighted.™
Short-sight and long-sight certainly tend to be inherited.*
The inferiority of Europeans, in comparison with savages,
in eyesight and in the other senses, is no doubt the accumu-
lated and transmitted effect of lessened use during many
generations; for Rengger® states that he has repeatedly
observed Europeans, who had been brought up and spent
their whole lives with the wild Indians, who nevertheless
35 “‘Intermarriage.’? By Alex. Walker, 1838, p. 377.
26 “The Variation of Animals under Domestication,” vol. i. p. 173.
%1 ‘“Principles of Biology,”’ vol. i. p. 455.
3 Paget, ‘‘Lectures on Surgical Pathology,”’ vol. ii., 1853, p. 209.
29 It is a singular and unexpected fact that sailors are inferior to lands-
men in their mean distance of distinct vision. Dr. B. A. Gould (‘‘Sanitary
Memoirs of the War of the Rebellion,’’ 1869, p. 530) has proved this to be the
case; and he accounts for it by the ordinary range of vision in sailors being
“restricted to the length of the vessel and the height of the masts.”’
3 “The Variation of Anim&ls under Domestication,”’ vol. i. p. 8.
31 “Saugethiere von Paraguay,’’ s. 8,10. I have had good opportunities
for observing the extraordinary power of eyesight in the Fuegians. See also
Lawrence (‘‘Lectures on Physiology,”’ etc., 1822, p. 404) on this same subject.
M. Giraud-Teulon has recently collected (‘‘Revue des Cours Scientifiques,”’
1870, p. 625) a large and valuable body of evidence proving that the cause
of short-sight ‘“‘c’est le travail assidu, de pres.”
56 THE DESCENT OF MAN
did not equal them in the sharpness 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 Kuropeans; and this probably
indicates a corresponding difference in the dimensions 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 per-
fect senses; and Prichard believes that the great breadth
of their skulls across the zygomas follows from their highly
developed sense-organs. *
The Quechua Indians inhabit the lofty plateaus of Peru;
and Alcide d’Orbigny states® that, from continually breath-
ing 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 observations have been doubted; but Mr. D. Forbes
carefully measured many Aymaras, an allied race, living at
the height of between ten thousand and fifteen thousand
feet; and he informs me™ that they differ conspicuously
from the men of all other races seen by him in the circum-
ference and length of their bodies. In his table of measure-
ments the stature of each man is taken at one thousand, 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;
82 Prichard, ‘‘Phys. Hist. of Mankind,”’ on the authority of Blumenbach, ,
vol. i., 1851, p. 311; for the statement by Pallas, vol. iv., 1844, p. 407.
38 Quoted by Prichard, ‘‘Researches into the Phys. History of Mankind,’
vol. v. p. 463.
34 Mr. Forbes’s valuable paper is now published in the ‘‘Journal of the
Ethnolog. Soc. of London,’’ new series, vol. ii., 1870, p. 193.
THE DESCENT OR ORIGIN OF MAN 57
while in two Europeans, measured at the same time, the
femora to the tibize 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 relation with
the greatly increased length of the trunk. The Aymaras
present some other singular points of structure, for instance,
the very small projection of the heel.
These men are so thoroughly acclimatized 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 mortality. Nevertheless Mr. Forbes found
a few pure families which had survived during two genera-
tions, and he observed that they still inherited their charac-
teristic 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; while
their femora had become somewhat lengthened, as had their
tibie, although in a less degree. The actual measurements
-mnay 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.*
Although man may not have been much modified during
the latter stages of his existence through the increased or
decreased use of parts, the facts now given show 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
8 Dr. Wilckens (“‘Landwirthschaft. Wochenblatt,’’ No. 10, 1869) has lately
published an interesting essay showing how domestic animals which live in
mountainous regions have their frames modified.
58 THE DESCENT OF MAN
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 while still retaining their
early condition. Various monstrosities come under this
head; and some, as a cleft-palate, are known to be occa-
sionally inherited. It will suffice for our purpose to refer
to the arrested brain-development of microcephalous idiots,
as described in Vogt’s memoir.** Their skulls are smaller,
and the convolutions of the brain are less complex than in
normal men. The frontal sinus, or the projection over the
eyebrows, is largely developed, and the jaws are prognathous
to an ‘‘effrayant’’ degree; so that these idiots somewhat re-
semble the lower types of mankind. Their intelligence and
most of their mental faculties are extremely feeble. KX They
cannot acquire the power of speech, and are wholly incapa-
ble of prolonged attention, but are much given to imitation.
They are strong and remarkably active, continually gambol-
ling and jumping about, and making grimaces. They often
ascend stairs on all-fours, and are curiously fond of climbing
up furniture or trees. We are thus reminded of the delight
shown 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. x 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 while 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 remarkably hairy.*”
36 “Mémoire sur les Microcéphales,’’ 1867, pp. 50, 125, 169, 171, 184-198,
31 Prof. Laycock sums up the character of brute-like idiots by calling them
theroid; ‘Journal of Mental Science,” July, 1863. Dr, Scott (‘The Deaf and
THE DESCENT OR ORIGIN OF MAN 59
Reversion.—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 pro-
genitor 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 per-
form 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.** There are other cases which come more strictly
Dumb,”’ 2d edit., 1870, p. 10) has often observed the imbecile smelling their
food. See, on this same subject, and on the hairiness of idiots, Dr. Maudsley,
“Body and Mind,’’ 1870, pp. 46-51. Pinel has also given a striking case of
hairiness in an idiot.
38 In my “Variation of Animals under Domestication’’ (vol. ii. p. 57) I
attributed the not very rare cases of supernumerary mammee in women to rever-
sion. I was led to this as a probable conclusion, by the additional mamme
being generally placed 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 mamme. But
I now find (see, for instance, Prof. Preyer, ‘‘Der Kampf um das Dasein,’’ 1859,
s. 45) that mamme erratice occur in other situations, as on the back, in the
armpit, and on the thigh; the mamme in this latter instance having given so
much milk that the child was thus nourished. The probability that the addi-
tional mammz are due to reversion is thus 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 mammez on the breast.
Five cases have been recorded of the presence of more than a pair of mamme
(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. Bartels in ‘‘Reich-
ert’s and du Bois-Reymond’s Archiv.,’’ 1872, p. 304, In one of the cases al-
luded to by Dr. Bartels, a man bore five mamme, 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 mammz 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 hesita-
60 THE D&SCENT OF MAN
under our present head of reversion. Certain structures,
regularly occurring in the lower members of the group to
which man belongs, occasionally make their appearance
in him, though not found in the normal human embryo;
or, if normally present in the human embryo, they become
abnormally developed, although in a manner which is nor-
mal, 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 gra-
dations 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 of body exists the cornua remain un-united. As the
tion, the frequent cases of polydactylism in men and various animals to rever-
sion. I was partly led to this through Prof. Owen’s statement, that some of
the Ichthyopterygia possess more than five digits, and therefore, as I supposed,
had retained a primordial condition; but Prof. Gegenbaur (‘‘Jenaischen Zeit-
schrift,’’ 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 cen-
tral chain of 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 inherited, but, as I then believed,
had the power of regrowth after amputation, like the normal digits of the lower
vertebrata. But I have explained 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, inasmuch as arrested develop-
ment and reversion are intimately related processes; that various structures in
an embryonic or arrested condition, such as a cleft palate, bifid uterus, ete., are
frequently accompanied 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 that there is any relation between the
development of supernumerary digits and reversion to some lowly organized
progenitor of man.
THE DESCENT OR ORIGIN OF MAN 61
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 ag
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 in-
stance 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 per-
forming’ the proper office of gestation. In other and rarer
cases, two distinct uterine cavities are formed, each having
its proper orifice and passage.” No such stage is passed
through during the ordinary development of the embryo,
and it is difficult to believe, though perhaps not impossible,
that the two simple, minute, primitive tubes should know
how (if such an expression may be used) to grow into two
distinct uteri, each with a well-constructed orifice and pas-
sage, 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 one 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 development, even after the. lapse
of an enormous interval of time.
Prof. Canestrini, after discussing the foregoing and vari-
ous analogous cases, arrives at the same conclusion as that
just given. He adduces another instance, in the case of the
malar bone,*® which, in some of the Quadrumana and other
39 See Dr, A. Farre’s well-known article in the ‘‘Cyclopxdia of Anatomy
and Physiology,” vol. v., 1859, p. 642. Owen, ‘‘Anatomy of Vertebrates, ” vol,
jii., 1868, p. 68%. Prof. Turner in “‘Mdinburgh Med. Journal,”’ February, 1865.
40 *Annuario della Soc. dei Naturalisti in Modena,”’ 1867, p. 83. Prof,
62 THE DESCENT OF MAN
mammals, normally consists of two portions. This is its
condition in the human foetus when two months old; and,
through arrested development, it sometimes remains thus in
man when adult, more especially in the lower prognathous
races. Hence Canestrini concludes that some ancient pro-
genitor of man must have had this bone normally divided
into two portions, which afterward 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 mam-
mals, 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 brachy-
cephalic type. 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 greater distance in the
long line of descent from their early semi-human 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.”
Canestrini gives extracts on this subject from various authorities. Laurillard
remarks that as he has found a complete similarity in the form, proportions
and connection of the two malar bones in several human subjects and in certain
apes, he cannot consider this disposition of the parts as simply aceidental. An-
other paper on this same anomaly has been published by Dr. Saviotti in the
“Gazzetta delle Cliniche,’’ Turin, 1871, where he says that traces of the division
may be detected in about two per cent of adult skulls; he also remarks that it
more frequently occurs in prognathous skulls, not of the Aryan race, than in
others. See also G. Delorenzi on the same subject, ‘‘Tre nuovi casi d’anomalia
dell’ osso, malare,’’ Torino, 1872, Also, E. Morselli, ‘‘Sopra una rara anomalia
dell’ osso malare,’’ Modena, 1872. Still more recently Gruber has written a
pamphlet on the division of this bone. I give these references because a re-
viewer, without «ny grounds or scruples, has thrown doubts on my statements,
41 A whole series of cases is given by Isid. Geoffroy St.-Hilaire, ‘“Hist. des
Anomalies,”’ tom. iii. p. 437, A reviewer (‘Journal of Anat, and Physiology,”
THE DESCENT OR ORIGIN OF MAN 63
In man, the canine teeth are perfectly efficient instru-
fhents for mastication. But their true canine character, as
Owen" remarks, ‘‘is indicated by the conical form of the
crown, which terminates in an obtuse point, is convex out-
ward 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 Aus-
tralian. 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 func-
tion is concerned, be considered as rudimentary. In every
large collection of human skulls some may be found, as
Hickel** observes, with the canine teeth projecting con-
siderably 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.** 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 Naulette jaw
they are spoken of as enormous.‘
Of the anthropomorphous apes the males alone have their
1871, p. 366) blames me much for not having discussed the numerous cases,
which have been recorded, of various parts arrested in their development. He
says that, according to my theory, ‘‘every transient condition of an. organ, dur-
ing its development, is not only a means to an end, but once was an end in it-
self.’? This does not seem to me necessarily to hold good. Why should not
variations occur during an early period of development, having no relation to
reversion; yet such variations might be preserved and accumulated, if in any
way serviceable, for instance, in shortening and simplifying the course of
development? And again, why should not injurious abnormalities, such as
atrophied or hypertrophied parts, which have no relation to a former state
of existence, occur at an early period, as well as during maturity?
42 “Anatomy of Vertebrates,’’ vol. ili., 1868, p. 323.
43 “‘Generelle Morphologie,’’ 1866, B. ii. s. elv.
4 Carl Vogt’s ‘Lectures on Man,?’ Eng. translat., 1864, p. 151. ;
45 CG, Carter Blake, on a jaw from La Naulette, ‘‘Anthropolog. Review,”
1867, p. 295. Schaaffhausen, ibid., 1868, p. 426.
o4 THE DESUVUENT OF MAN
canines fully developed; but in the female gorilla, and ina
less degree in the female orang, these teeth project consid-
erably beyond the others; therefore the fact, of which I have
been assured, that women sometimes have considerably pro-
jecting canines, is no serious objection to the belief that their
occasional great development in man is a case of reversion
to an apelike prcegenitor. XHe 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 fore-
fathers having been provided 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),*° 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. Prof.
Vlacovich*’ examined forty male subjects, and found a mus-
cle, 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 de-
veloped 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 intelligfble; 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,‘*® has
4 *‘The Anatomy of Expression,’’ 1844, pp. 110, 131.
41 Quoted by Prof. Canestrini in the ‘‘Annuario,”’ etc., 1867, p. 90.
48 These papers deserve careful study by any one who desires to learn how
frequently our muscles vary, and in varying come to resemble those of the
Quadrumana. The following references relate to the few points touched on
jn my text: ‘Proc. Royal Soc., vol. xiv., 1865, pp. 379-384; vol. xv., 1866,
pp. 241, 242; vol. xv., 186%, p. 544; vol. xvi., 1868, p. 524. I may here add
that Dr. Murie and Mr. St. George Mivart have shown in their Memoir on the
Lemuroidea (‘‘Transact. Zoolog. Soc.,”’ vol. vii., 1869, p. 96) how extraordinarily
THE DESCENT OR ORIGIN OF MAN 65
minutely described a vast number of muscular variations
in man, which resemble normal structures in the lower
animals. The muscles which closely resemble those regu-
larly present in our nearest allies, the Quadrumana, are’ too
numerous to be here even specified. In a single male sub-
ject, having a strong bodily frame, and well-formed skull,
no less than seven muscular variations 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 clavicule,’’ such as is
found in all kinds of apes, and which is said to occur in
about one out of sixty human subjects.“ Again, this man
had ‘‘a special abductor of the metatarsal bone of the fifth
digit, such as Prof. Huxley and Mr. Flower have shown
’ to exist uniformly in the higher and lower apes.’’ I will
give only two additional cases; the acromio-basilar muscle is
found in all mammals below man, and seems to be correlated
with a quadrupedal gait, and it occurs in about one out of
sixty human subjects. In the lower extremities Mr. Brad-
ley®* 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. Such resemblances 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
variable some of the muscles are in these animals, the lowest members of the
Primates. Gradations, also, in the muscles leading to structures found in ani-
mals still lower in the scale, are numerous in the Lemuroidea,
49 See also Prof. Macalister in ‘‘Proc. R. Irish Academy,’’ vol. x., 1868,
, 124,
50 Mr. Champneys in ‘‘Journal of Anat. and Phys.,’’ Nov., 1871, p. 178.
51 ‘Journal of Anat. and Phys.,’’ May, 1872, p. 421. ;
8 Prof, Macalister (ibid., p. 121) has tabulated his observations, and finds
that muscular abnormalities are most frequent in the forearms, secondly, in the
face, thirdly, in the foot, ete.
66 THE DESCENT OF MAN
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 comprehen-
sive knowledge of general and scientific anatomy.” ©
That this unknown factor is reversion to a former state
of existence may be admitted as in the highest degree prob-
able. 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 con-
nection between them. On the other hand, if man is de-
scended from some apelike creature, no valid reason can
be assigned why certain muscles should not suddenly reap-
pear after an interval of many thousand generations; in the
same manner as, with horses, asses and mules, dark-colored
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
53 The Rev. Dr. Haughton, after giving (‘‘Proc. R. Irish Academy,’’ June
27, 1864, p. 715) a remarkable case of variation in the human flexor pollicis
longus, adds: ‘“‘This remarkable example shows that man may sometimes
possess the arrangement of tendons of thumb and fingers characteristic of the
macaque; but whether such a case should be regarded as a macaque passing
upward into a man, or a man passing downward into a macaque, or as a con-
genital freak of nature, I cannot undertake to say.’’ It is satisfactory to hear
so capable an anatomist, and so imbittered an opponent of evolutionism, admit-
ting even the possibility of either of his first propositions. Prof. Macalister has
also described (‘‘Proc. R. Irish Acad.,”’ vol. x., 1864, p. 138) variations in the
flexor pollicis longus, remarkable from their relations to the same muscle in
the Quadrumana.
54 Since the first edition of this book appeared, Mr. Wood has published
another memoir in the ‘‘Phil. Transactions,’’ 1870, p. 83, on the varieties of
the muscles of the human neck, shoulder and chest. He here shows how ex-
tremely variable these muscles are, and how often and how closely the varia-
tions resemble the normal muscles of the lower animals, He sums up by re-
murking: ‘‘It will be enough for my purpose if I have succeeded in showing
the more important forms which, when occurring as varieties in the human sub-
ject, tend to exhibit in a sufficiently marked manner what may be considered as
proofs and examples of the Darwinian principle of reversion, or law of atishie
tance, in this department of anatomical science.’
THE DESCENT OR ORIGIN OF MAN 67
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 condi-
tion, the same organ in its normal state in certain mammals.
Some parts which are rudimentary in man, as the os coceyx
in both sexes, and the mamme in the male sex, are always
present; while others, such as the supra-condyloid foramen,
only occasionally appear, and therefore might have been in-
troduced under the head of reversion. These several rever-
sionary structures, as well as the strictly rudimentary ones,
reveal the descent of man from some lower form in an un-
mistakable manner. °
Correlated Variation.—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 part. Various monstrosities, as I. Geof-
froy repeatedly insists, are thus intimately connected.
Homologous structures are particularly liable to change
together, as we see on the opposite sides of the body, and
in the upper and lower extremities. Meckel long ago re-
marked, 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 leg. The organs of
sight and hearing, the teeth and hair; the color of the skin
and of the hair, color and constitution, are more or less cor-
related.** Prof. 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 spon-
55 The authorities for these several statements are given in my ‘‘Variation
of Animals under Domestication,’’ vol. ii. pp. 320-335,
68 THE DESCENT OF MAN
taneous, for to our ignorance they appear to arise without
any exciting cause. It can, however, be shown that such
variations, whether consisting of slight individual differ-
ences, or of strongly marked and abrupt deviations of
structure, depend much more on the constitution of the
organism than on the nature of the conditions to which
it has been subjected.
Rate of Increase.—Civilized populations have been known
under favorable conditions, as in the United States, to double
their numbers in twenty-five years; and, according to a cal-
culation by Euler, this might occur in a little over twelve
years.°’ 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 civilized 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 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 counter-
balanced, and more than counterbalanced, in nations placed
under favorable 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
56 This whole subject has been discussed in chap. xxiii. vol. ii. of my
*‘Variation of Animals and Plants under Domestication.’’
51 See the ever-memorable ‘‘Essay on the Principle of Population,’’ by the
Rey, T, Malthus, vol, i,, 1826, pp, 6, 517.
THE DESCENT OR ORIGIN OF MAN 69
the reproductive power is actually less in barbarous than in
civilized 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 civilized men,
would be actually less prolific. I have shown in a former
work,®* that all our domesticated quadrupeds and birds, and
all our cultivated plants, are more fertile than the corre-
sponding species in a state of nature. It is no valid objec-
tion 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, ex-
pect that civilized men, who in one sense are highly domes-
ticated, would be more prolific than wild men. It is also
probable that the increased fertility of civilized nations would
become, as with our domestic animals, an inherited charac-
ter: it is’ at least known that with mankind a tendency
to produce twins runs in families.”
Notwithstanding that savages appear to be less prolific
than civilized people, they would no doubt rapidly increase
if their numbers were not by some means rigidly kept down.
The Santali, or hill-tribes of India, have recently afforded a
good illustration of this fact; for, as shown by Mr. Hunter,”
they have increased at an extraordinary rate since vaccina-
tion 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
58 ‘Variation of Animals and Plants under Domestication,”’ vol. ii. pp. 111-
113, 163, ‘i
89 Mr. Sedgwick, ‘British and Foreign Medico-Chirurg. Review,’’ July,
1863, p. 170.
60 “The Annals of Rural Bengal,” by W. W. Hunter, 1868, p. 259,
70 : THE. DESCENT OF MAN
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 earliest possible age.
The young men are often required to show 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
civilized 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 periodical, depending chiefly on
extreme seasons, all tribes must fluctuate in number. They
cannot steadily and regularly increase, as there is no arti-
ficial 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
neighbors. 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 of tigers.
Malthus has discussed these several checks, but he does
not lay stress enough on what is probably the most impor-
tant 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™ has
shown, on a still more extensive scale. These practices
appear to have originated in savages recognizing the diffi-
culty, or rather the impossibility, of supporting all the in-
fants that are born. Licentiousness may also be added to
the foregoing checks; but this does not follow from failing
61 ‘‘Primitive Marriage,’’ 1865.
THE DESCENT OR ORIGIN OF MAN 71
means of subsistence; though there is reason to believe that
in some cases (as in Japan) it has been intentionally encour-
aged 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 practiced infanticide or
polyandry; for the instincts of the lower animals are never
so perverted” as to lead them regularly 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 rap-
idly; 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 ele-
phant, 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 America was at first in any
sensible degree increased; or that, as each district became
fully stocked, this same power was diminished. No doubt
6 A writer in the “‘Spectator’’ (March 12, 1871, p. 320) comments as fol-
lows on this passage: ‘‘Mr. Darwin finds himself compelled to reintroduce a
new doctrine of the fall of man. He shows that the instincts of the higher
animals are far nobler than the habits of savage races of men, and he finds him-
self, therefore, compelled to reintroduce—in a form of the substantial orthodoxy
of which he appears to be quite unconscious—and to introduce as a scientific
hypothesis the doctrine that man’s gain of knowledge was the cause of a tem-
porary but long-enduring moral deterioration, as indicated by the many foul
customs, especially as to marriage, of savage tribes. What does the Jewish
tradition of the moral degeneration of man through his snatching at a knowl-
edge forbidden him by his highest instinct assert beyond this?”’
72 THE DESCENT OF MAN
in this case, and in all others, many checks concur, and
different checks under different circumstances; periodical
dearths, depending on unfavorable seasons, being probably
the most important of all. So it will have been with the
early progenitors of man.
Natural Selection.—We have now seen that man is vari-
able in body and mind; and that the variations are induced,
either directly or indirectly, by the same general causes, and
obey the same general laws, as with the loweranimals. Man
has spread widely over the face of the earth, and must have
been exposed, during his incessant migrations,” to the most
diversified conditions. The inhabitants of Tierra del Fuego,
the Cape of Good Hope, and Tasmania in the one hemi-
sphere, and of the Arctic regions in the other, must have
passed through many climates, and changed their habits
many times, before they reached their present homes.“
The early progenitors of man must also have 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, 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 individ-
ual differences. We know, for instance, that the muscles
of our hands and feet, which determine our powers of move-
ment, are liable, like those of the lower animals,® to inces-
sant variability. If then the progenitors of man inhabiting
any district, especially one undergoing some change in its
conditions, were divided into two equal bodies, the one-half
63 See some good remarks to this effect by W. Stanley Jevons, ‘‘A Deduc-
tion from Darwin’s Theory,’’ ‘‘Nature,’’ 1869, p. 231.
64 Latham, ‘‘Man and his Migrations,’’ 1851, p. 135,
65 Messrs. Murie and Mivart in their ‘‘Anatomy of the Lemuroidea’’ (‘‘Trans-
act. Zoolog. Soc.,’’ vol. vii. 1869, pp. 96-98) say: ‘‘Some muscles are so irregular
in their distribution that they cannot be well classed in any of the above groups.’?
These muscles differ even on the opposite sides of the same individual.
THE DESCENT OR ORIGIN OF MAN 73
which included all the individuals best adapted by their
powers of movement for gaining subsistence, or for defend-
ing themselves, would on an average survive in greater
numbers, and procreate 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 than any other highly organized
form, and all others have yielded before him. He mani-
festly owes this immense superiority to his intellectual facul-
ties, 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,” ‘‘a psychological analysis of
the faculty of language shows that even the smallest pro-
ficiency in it might require more brain DNS than the great-
est proficiency in any other direction.’’ He has invented
and is able to use various weapons, tools, traps, etc., with
which he defends himself, kills or catches prey, and other-
wise obtains food. He has made rafts or canoes for fishing
or crossing over to neighboring fertile islands. He has dis-
covered the art of making fire, by which hard and stringy
roots can be rendered digestible, and poisonous roots or
“herbs innocuous. This discovery of fire, probably the great-
est ever made by man, excepting language, dates from be-
fore 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”
66 Limits of Natural Selection, ‘‘North American Review,’’ October, 1870,
p. 295,
“Quarterly Review,” April, 1869, p. 392. This subject is more fully dis-
cussed in Mr. Wallace’s ‘<Contributions to the Theory of Natural Selection,’
1870, in which all the essays referred to in this work are republished. The
Descent—Vo., I.—4
TE ; THE DESCENT OF MAN
maintains 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 importance of his bodily structure, to which subject the
remainder of this chapter will be devoted; the development
of the intellectual and social or moral faculties being dis-
cussed 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 de-
fending himself, or in killing birds, requires the most con-
summate 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 must 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 barbed
spear or hook from a bone, demands the use of a perfect
hand; for, as a most capable judge, Mr. Schoolcraft, re-
marks, the shaping fragments of stone into knives, lances,
or arrow-beads shows ‘‘extraordinary ability and long prac-
tice.”” This is to a great extent proved by the fact that
primeval men practiced a division of labor; each man did
not manufacture his own flint tools or rude pottery, but cer-
tain individuals appear to have devoted themselves to such
work, no doubt receiving in exchange the produce of the
‘‘Bssay on Man’? has been ably criticised by Prof. Claparéde, one of the most
distinguished zoologists in Europe, in an article published in the ‘‘Bibliothéque
Universelle,’’? June, 1870. The remark quoted in my text will surprise every
one who has read Mr. Wallace’s celebrated paper on ‘“‘The Origin of Human
Races deduced from the Theory of Natural Selection,”’ originally published in
the ‘‘Anthropological Review,’’ May, 1864, p. elviii. I cannot here resist quot-
ing a most just remark by Sir J. Lubbock (‘‘Prehistoric Times,’ 1865, p. 479)
in reference to this paper, namely, that Mr. Wallace, ‘‘with characteristic un-
selfishness, ascribes it (¢.e., the idea of natural selection) unreservedly to Mr.
Darwin, although, as is well known, he struck out the, idea independently,
and published it, though not with the same elaboration, at the same time.’’
6 Quoted by Mr. Lawson Tait in his ‘‘Law of Natural Selection,” ‘‘Duvlin
Quarterly Journal of Medical Science,’’ Feb., 1869. Dr. Keller is likewise
quoted to the same effect.
THE DESCENT OR ORIGIN OF MAN 75
chase. Archeologists are convinced that an enormous in-
terval of time elapsed before our ancestors thought of grind-
ing chipped flints into smooth tools. One can hardly doubt
that a manlike animal who possessed a hand and arm suffi-
ciently 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 civilized man can make. The structure of the hand
in this respect may be compared with that of the vocal or-
gans, 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 the 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 diversified 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.” 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 ob-
jects, such as the neck of a bottle, to their mouths. Ba-
boons 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. Ameri-
can 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
69 Owen, ‘‘Anat, of Vertebrates,”’ iii. p 71.
76 THE DESCENT OF MAN
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.
It seems to me far from true that because ‘‘objects are
grasped clumsily’? by monkeys, ‘‘a much less specialized
organ of prehension’? would have served them” 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.”
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;” 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 atti-
tude, "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 ad-
7 “Quarterly Review,” April, 1869, p. 392.
1 In Hylobates syndactylus, as the name expresses, two of the toes regu-
larly cohere; and this, as Mr. Blyth informs me, is occasionally the case with
the toes of A agilis, lar, and leuciscus. Colobus is strictly arboreal and
extraordinarily active (Brehm, “‘Thierlehen,’’? B. i. s, 50), but whether a better
climber than the species of the allied genera, I do not know. It deserves
notice that the feet of the sloths, the most arboreal animals in the world, are
wonderfully hooklike.
‘2 Brehm, ‘‘Thierleben,” B, i. s, 80.
THE DESCENT OR ORIGIN OF MAN 77
mirably adapted to act in obedience to his will. SirC. Bell”
insists that ‘‘the hand supplies all instruments, and by its
correspondence with the intellect gives him universal domin-
ion.”” 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 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 modified, though this
has entailed the almost complete loss of its power of prehen-
sion. It accords with the principle of the division of physi-
ological labor prevailing throughout the animal kingdom,
that as the hands became perfected for prehension, the feet
should have become perfected for support and locomotion.
With some savages, however, the foot has not altogether
lost its prehensile power, as shown by their manner of climb-
ing trees, and of using them in other ways.”
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 ad-
vantageous to the progenitors of man to have become more
and more erect or bipedal. They would thus have been
7 *‘The Hand,” etc., ‘‘Bridgewater Treatise,’’? 1833, p. 38.
™ Hackel has an excellent discussion on the steps by which man became
a biped; ‘‘Natirliche Schépfungsgeschichte,’’? 1868, s. 50%. Dr. Buchner
(‘‘Conférences sur la Théorie Darwinienne,’’ 1869, p. 135) has given good
eases of the use of the foot as a prehensile organ by man; and has also written
on the manner of progression of the higher apes, to which I allude in the fol-
lowing paragraph; see also Owen (‘‘Anatomy of Vertebrates,”’ vol. iii. p. 71) on
this latter subject.
78 THE DESCENT OF MAN
better able to defend themselves with stones or clubs, to
attack their prey, or otherwise 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 quad-
ruped into a biped, as all the individuals in an intermediate
condition would have been miserably ill-fitted for progres-
sion. 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
on 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 ex-
isting monkeys a manner of progression intermediate between
that of a quadruped and a biped; but, as an unprejudiced
judge” insists, the anthropomorphous apes approach in
structure more nearly to the bipedal than to the quadru-
pedal type.
As the progenitors of man became more and more erect,
with their hands and arms more and more modified for pre-
hension 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 nec-
essary. 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. Schaaft-
hausen” maintains that ‘‘the powerful mastoid processes of
78 Prof. Broca, La Constitution des Vertébres caudales: ‘‘La Revue d’An-e
thropologie,”? 1872, p. 26 (separate copy).
%6 “Qn the Primitive Form of the Skull,” translated in “Anthropological
THE DESCENT OR ORIGIN OF MAN 79
the human skull are the result of his erect position’; and
these processes are absent in the orang, chimpanzee, etc.,
and are smaller in the gorilla than in man. Various other
structures, which appear connected with man’s erect posi-
tion, 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 habit-
ual use, this shows that certain actions are habitually per-
formed 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 indirect manner to other modifications of structure.
The early male forefathers of man were, as previously stated,
probably 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 complete disappearance of
the canine teeth in male ruminants, apparently in relation
with the development of their horns; and in horses, in rela-
tion to their habit of fighting with ‘their incisor teeth and
hoofs.
In the adult male anthropomorphous apes, as Riitimeyer™
and others have insisted, it is the effect on the skull of the
Review,’? Oct., 1868, p. 428. Owen (‘‘Anatomy of Vertebrates,” vol. ii.,
1866, P. 651) on the mastoid processes in the higher apes.
‘Die Grenzen der Thierwelt, eine Betrachtung zu Darwin’s Lehre,”
1868, 8. 51.
80 THE DESCENT OF MAN
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.’’ There-
fore, 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 analo-
gous 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 intelli-
gent orders, such as beetles.”* 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 cere-
bral 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 ‘he 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 civilized races, of ancient and modern
people, and by the analogy of the whole vertebrate series.
8 Dujardin, ‘‘Annales des Sc. Nat.,’’ 3d series, Zoolog., tom. xiv., 1850,
p. 203. See also Mr. Lowne, “Anatomy and Phys. of the Musca vomitoria, %
1870, p. 14. My son, Mr. F, Darwin, dissected igs me the cerebral ganglia ‘of
the Formica rufa,
)
THE DESCENT OR ORIGIN OF MAN 81
Dr. J. Barnard Davis has proved,” by many careful meas-
urements, that the mean internal capacity of the skull in
Europeans is 92.3 cubic inches; in Americans 87.5; in Asi-
atics 87.1; and in Australians only 81.9 cubic inches. Prof.
Broca® found that the nineteenth century skulls from graves
in Paris were larger than those from vaults of the twelfth
century, in the proportion of 1484 to 1426; and that the
increased size, as ascertained by measurements, was exclu-
sively in the frontal part of the skull—the seat of the intel-
lectual 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 capa-
cious.“ With respect to the lower animals, M. E. Lartet,”
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 convo-
lutions are more complex in the more recent forms. On.the
other hand, I have shown™ that the brains of domestic rab-
bits 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 genera-
tions, so that they have exerted their intellect, instincts,
senses, and voluntary movements but little.
19 ‘Philosophical Transactions,’’ 1869, p. 513.
80 “Tes Sélections,’? M. P. Broca, ‘‘Revue d’Anthropologie,’’? 1873; see
also, as quoted in C. Vogt’s “‘Lectures on Man,’’ Eng. translat., 1864, pp. 88,
90. Prichard, ‘‘Phys. Hist. of Mankind,”’ vol. i., 1838, p. 305.
81 In the interesting article just referred to, Prof. Broca has well remarked,
that in civilized nations the average capacity of the skull must be lowered by
the preservation of a considerable number of individuals, weak in mind and
body, who would have been promptly eliminated in the savage state. On the
other hand, with savages, the average includes only the more capable individ-
uals, who have been able to survive under extremely hard conditions of life.
Broca thus explains the otherwise inexplicable fact, that the mean capacity of
the skull of the ancient Troglodytes of Lozére is greater than that of modern
Frenchmen,
82 “Comptes rendus des Sciences,”’ etc., June 1, 1868.
8 “The Variation of Animals and Plants under Domestication,
pp. 124-129. :
” vol. i.
82 THE DESCENT OF MAN
The gradually increasing weight of the brain and skull
in man must have influenced the development of the sup-
porting spinal column, more especially while he was becom-
ing erect. As this change of position was being brought
about, the internal pressure of the brain will also have in- |
fluenced the form of the skull; for many facts show how
easily the skull is thus affected. Hthnologists believe that
it is modified by the kind of cradle in 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 sidewise or
backward, owing to disease, one of the two eyes has changed
its position, and the shape of the skull has been altered ap-
parently by the pressure of the brain in a new direction.“
I have shown that with long-eared rabbits even so trifling a
cause as the lopping forward of one ear drags forward almost
every bone 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 altered. I infer this
from my observations on domestic rabbits, some kinds of
which have become very much larger than the wild animal,
while 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
84 Schaaffhausen gives from Blumenbach and Busch the cases of the
spasms and cicatrix, in ‘‘Anthropol. Review,’’ Oct., 1868, p. 420. Dr. Jarrold
(‘‘Anthropologia,’’ 1808, pp. 115, 116) adduces from Camper and from his
own observations, cases of the modification of the skull from the head being
fixed in an unnatural position. He believes that in certain trades, such as that
of a shoemaker, where the head is habitually held forward, the forehead
becomes more rounded and prominent.
THE DESCENT OR ORIGIN OF MAN 83
large domestic kind, the former was 8.15 and the latter 4.3
inches in length.** 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’’ ;** and tall men may be compared with the
larger and longer-bodied rabbits, all of which have elongated
skulls, or are dolichocephalic.
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 compari-
son 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 hippo-
potamus are naked; and this may be advantageous to them
for gliding through the water; nor would it be injurious to
them from the 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 rhinoceroses are almost hairless; and as cer-
tain extinct species, which formerly lived under an Arctic
climate, were covered with long wool or hair, it would al-
most 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” 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
8 ‘Variation of Animals,’’ ete., vol. i. p. 117, on the elongation of the
skull; p. 119, on the effect of the lopping of one ear.
%© Quoted by Schaaffhausen, in *Anthropolog. Review,’ aha 1868, p. 419,
81 Owen, ‘‘Anatomy of Vertebrates,’’ vol. ili. p. 619. :
».
84 THE DESCENT OF MAN
with the trunk, favors the 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,™ is op-
posed to the supposition that man became naked through
the action of the sun. Mr. Belt believes® 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 through natural selection, may be doubted, since
none of the many quadrupeds inhabiting the tropics has,
as far as I know, acquired any specialized means of relief.
The view which seems to me the most probable is that man,
or rather primarily woman, became divested of hair for orna-
mental purposes, as we shall see 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
88 Isidore Geoffroy St.-Hilaire remarks (“‘Hist. Nat. Générale,’ tom. ii.,
1859, pp. 215-217) on the head of man being covered with long hair; also on
the upper surfaces of monkeys and of other mammals being more thickly clothed
than the lower surfaces. ~ This has likewise been observed by various authors,
Prof. P. Gervais (‘‘Hist. Nat. des Mammifeéres,’’ tom. i,, 1854, p. 28), however,
states that in the Gorilla the hair is thinner on the back, ‘where it is partly
rubbed off, than on the lower surface.
89 “The Naturalist in Nicaragua,’? 1874, p. 209. As some confirmation
of Mr. Belt’s view, I may quote the following passage from Sir W. Denison
(‘Varieties of Vice-Regal Lnfe,”? vol. i, 1870, p. 440): ‘It is said to be a
practice with the Australians, when the vermin get troublesome, to singe
themselves.”’
THE DESCENT OR ORIGIN OF MAN 85
is eminently distinctive of man; but as those apes which
come nearest to him are destitute of this organ, its disap-
pearance does not relate exclusively to man. The tail often
differs remarkably in length within the same genus; thus in
some species of Macacus it is longer than the whole body,
and is formed of twenty-four vertebre; in others it consists
of a scarcely visible stump, containing only three or four
vertebrz. In some kinds of baboons there are twenty-five,
while in the mandrill there are ten very small stunted caudal
vertebrz, or, according to Cuvier, sometimes only five.
The tail, whether it be long or short, almost always tapers
toward the end; and this, I presume, results from the atro-
phy of the terminal muscles, together with their arteries and
nerves, through disuse, leading to the atrophy of the termi-
nal 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 disappearance of the tail. Prof. Broca has recently
shown” that the tail in all quadrupeds consists of two por-
tions, generally separated abruptly from each other; the
basal portion consists of vertebre, more or less perfectly
channelled and furnished with apophyses like ordinary ver-
tebre; whereas those of the terminal portion are not chan-
nelled, are almost smooth, and scarcely resemble true verte-
bre. 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 por-
tion the vertebre, constituting the os coccyx, are quite rudi-
mentary, being much reduced in size and number. In the
basal portion the vertebre are likewise few, are united
firmly together, and are arrested in development; but they
have been rendered much broader and flatter than the corre-
sponding ‘vertebre in the tails of other animals; they consti-
9 Mr. St, George Mivart, ‘‘Proe. Zoolog. Soc.,”’ 1865, pp. 562, 583. Dr. J.
E. Gray, ‘‘Cat. Brit. Mus.: Skeletons.’? Owen, ‘‘Anatomy of Vertebrates,”
vol. ii. p. 517. Isidore Geoffroy, ‘“‘Hist. Nat. Gén.,”’ tom. ii. p, 244,
1 “Revue d’Anthropologie,”? 1872; ‘La Constitution des Vertébres cau-
dales,’?
86 THE DESCENT OF MAN
tute what Broca calls the accessory sacral vertebra. These
are of functional importance by supporting certain internal
parts and in other ways; and their modification is directly
connected with the erect 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 modification, therefore, of the
basal caudal vertebree 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 vari-
able vertebrae of the terminal portion of the tail, forming the
os coccyz? 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 ap-
pears. Dr. Anderson™ states that the extremely short tail
of Macacus brunneus is formed of eleven vertebra, including
the imbedded basal ones. The extremity is tendinous and
contains no vertebra; this is succeeded 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
vertebra. This short tail is carried erect; but about a quar-
ter of its total length is doubled on to itself to the left; and
this terminal part, which includes the hooklike portion,
serves ‘‘to fill up the interspace between the upper diver-
gent portion of the callosities’’; so that the animal sits on
it, and thus renders it rough and callous. Dr. Anderson
thus sums up his observations: ‘“‘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 exterd beyond
the extremity of the ischial tuberosities it seems as if the
# “Prog. Zoolog. Soc.,’’? 1872, p. 310.
THE DESCENT OR ORIGIN OF MAN 87
tail originally had been bent round, by the will of the ani-
mal, 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
circumstances it is not surprising that the surface of the
tail should have been roughened and rendered callous;
and Dr. Murie,* 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 ‘tis necessarily thrust to one side of the
buttocks; and whetlier long or short its root is consequently
liable to be rubbed or chafed.’” As we now have evidence
that mutilations occasionally produce an inherited effect,
it is not very improbable that in short-tailed monkeys the
projecting part of the tail, being functionally useless, c:suid
after many generations have become rudimentary and dis-
torted, 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 imbedded portion
having been reduced and modified, so as to become suitable
to the erect or semi-erect position.
I have now endeavored to show 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
%8 **Proc, Zoolog. Soc.,’? 1872, p. 786.
% T allude to Dr. Brown-Séquard’s observations on the transmitted effect
of an opera.ion causing epilepsy in guinea-pigs, and likewise more recently on
the analogous effects of cutting the sympathetic nerve in the neck. I shall here-
after have d2casion to refer to Mr. Salvin’s interesting case of the apparently
inherited efiects of mot-mots biting off the barbs of their own tuil-feathers,
See also, on the general subject, ‘‘Variation of Animals and Plants under
Domesticati«n,’’ vol. ii. pp. 22-24.
88 THE DESCENT OF MAN
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 shown 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 won-
deriu! growth of galls on plants caused by the poison of
an insect, and on the remarkable changes of color in the
plumage of parrots when fed on certain fishes, or inocu-
lated with the poison of toads; 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 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 of Nageli on plants, and
the remarks by various authors with respect to animals,
more especially those recently made by Prof. 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 of 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
% ‘The Variation of Animals and Plants under Domestication,‘’ vol. ii. pp.
280, 282. 4
THE DESCENT OR ORIGIN OF MAN 89
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: first, to show 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 unrecog-
nized, service. Any one with this assumption in his mind
would naturally extend too far the action of natural selec-
tion, either during past or present times. Some of those who
admit the principle of evolution, but reject natural selection,
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. X
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
the individuals of each species, for reversion only carries the
problem a few steps backward; but each peculiarity must
have had its efficient cause. If these causes, whatever they
may be, were to act more uniformly and energetically dur-
ing a lengthened period (and against this no reason can be
90 THE DESCENT OF MAN
assigned), the result would probably be not a mere slight in-
dividual difference, but a well-marked and constant modifi-
cation, 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. Uniformity of character would, how-
ever, 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 modifi-
cations, 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
spontaneous 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 multi-
form individual differences or slight variations, so no doubt
were the early progenitors of man; the variations being for-
merly induced by the same general causes, and governed by
the same general and 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 nat-
ural‘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 ap-
pears, also, as we shall hereafter see, that various unimpor-
tant 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 devi-
ations of structure in our domestic productions.
Judging from the habits of savages and of the greater
THE DESCENT OR ORIGIN OF MAN 91
number of the Quadrumana, primeval meh, and even their
apelike 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 in-
cludes a large number of well-endowed individuals increases
in number, and is victorious over other less favored ones,
even although each separate member gains no advantage
over the others of the same community. Associated insects
have thus acquired many remarkable 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 second-
ary service to it. For instance, the horns of ruminants and
the great canine teeth of baboons appear to have been ac-
quired by the males as weapons for sexual strife, but they |
are used in defence of the herd or troop. In regard to cer-
tain mental powers the case, as we shall see in the fifth chap-
ter, is wholly different; for these faculties have been chiefly,
or even exclusively, gained for the benefit of the commu-
nity, 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 crea-
tures 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’ that ‘‘the human .
frame has diverged from the structure of brutes, in the direc-
tion of greater physical helplessness and weakness. That is
to say, it is a divergence which of all others it is most im-
possible 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
9% ‘Primeval Man,’’ 1869, p. 66. _
92 THE DESCENT OF MAN
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 can-
not climb quickly, and so escape from enemies. The loss
of hair would not have been a great injury to the inhabi-
tants 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 develop-
ment 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 and weaker, than his ances-
tors. We should, however, 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 effect-
ually have checked the acquirement of the higher 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, etc., are more than counterbalanced: first, by his
intellectual powers, through which he has formed for him-
self weapons, tools, ete., though still remaining in a barba-
rous state; and, secondly, by his social qualities, which lead
him to give and receive aid from his fellow-men. No coun-
try in the world abounds in a greater degree with dangerous
beasts than Southern Africa; no country presents more fear-
ful 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 Eskimos in the
THE DESCENT OR ORIGIN OF MAN 93
Arctic regions. The ancestors of man were, no doubt, in-
ferior 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, while gradually losing their brutelike powers,
such as that of climbing trees, etc. But these ancestors
would not have been exposed to any special danger, even
if far more helpless and defenceless than any existing sav-
ages, had they inhabited some warm continent or large isl-
and, 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 favorable conditions, have sufficed to
raise man to his present high position in the organic scale.
94 THE DESCENT OF MAN
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—A ttention — Memory — Imagination—Reason—
Progressive improvement—Tools and weapons used by animals—
Abstraction, self-consciousness—Language—Sense of beauty—Belief
in God, spiritual agencies, superstitions
E 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,’ with that of the most highly organized ape.
The difference would, no doubt, still remain immense, even
if one of the higher apes had been improved or civilized as
much as a dog has been in comparison with its parent-form,
the wolf or jackal. The Fuegians rank among 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
1 See the evidence on those points, as given by Lubbock, ‘‘Prehistoric
Times,’’ p. 354, ete.
THE DESCENT OR ORIGIN OF MAN 95
& wholly different nature from those of the lower animals,
then we should never have been able to convince ourselves
that our high faculties had been gradually developed. But
it can be shown 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 lancelet, 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
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 Shakespeare. 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 show that there is no
fundamental difference between man and the higher mam-
mals in their mental faculties. Hach 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 acceptedXI shall arrange my
remarks in the order most convenient 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. x
With respect to animals very low in the scale, I shall
give some additional facts under Sexual Selection, showing
that their mental powers are much higher than might have
been expected. The variability of the faculties in the indi-
viduals 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 inquiry, that it is the unanimous
opinion of all those who have long attended to animals of
96 THE DESCENT OF MAN
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 inquiry as how life itself first originated.
These are problems for the distant future, if they are ever
to be solved by man.
XAs 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 off-
spring, 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 Hastern islands, and
the chimpanzee in “Africa, build platforms 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 fee]
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 turned out in the spring, often eat poisonous herbs,
which they afterward avoid, we cannot feel sure that the
apes do not learn from their own experience or from that
of their parents what fruits to select. It is, however, cer-
tain, as we shall presently see, that apes have an instinctive
dread of serpents, and probably of other dangerous animals.
The fewness and the comparative simplicity of the in-
stincts in the higher animals are remarkable in contrast
with those of the 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,? has
2 “T/Instinet chez Jes Insectes,’’ ‘Revue des Deux Mondes,’’ Feb., 1870,
p. 690.
THE DESCENT OR ORIGIN OF MAN 97
shown that no such inverse ratio really exists. Those in-
sects which possess the most wonderful instincts are cer-
tainly the most intelligent. In the vertebrate series, the
least intelligent members, namely fishes and amphibians,
do not possess complex instincts; and among 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.®
Although the first dawnings of intelligence, according
to Mr. Herbert Spencer,* have been developed through the
multiplication and co-ordination of reflex actions, and al-
though many of the simpler instincts graduate into reflex
actions, and can hardly be distinguished from them, as in
the case of young animals sucking, yet the more complex
instincts seem to have originated independently of intelli-
gence. Iam, however, very far from wishing to deny that
instinctive actions may lose their fixed and untaught charac-
ter, 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 variations of simpler instinctive
actions. Such variations appear to arise from the same
unknown causes acting on the cerebral organization which
induce slight variations or individual differences in other
parts of the body; and these variations, owing to our igno-
rance, are often said to arise spontaneously. We can, I
think, come to no other conclusion with respect to the ori-
gin of the more complex instincts, when we reflect on the
marvellous instincts of sterile worker-ants and bees, which
3 “The American Beaver and his Works,”’ 1868.
_ 4-*"Tne Principles of Psychology,’’ 2d edit., 1870, pp. 418-443,
Descent—Vo.u. I.—5
98 THE DESCENT OF MAN
leave no offspring 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 learned voluntarily, can soon through habit be per-
formed 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 modi-
fication 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 consequence, each sepa-
rate part would perhaps tend to be less well fitted to answer
to particular sensations or associations in a definite and in-
herited—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 in-
herited habits; for, as a sagacious physician remarked to
me, persons who are slightly imbecile tend to act in every-
thing by routine or habit, and they are rendered much
happier if this is encouraged.
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 fore-
sight, 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 intel-
ligence on the part of the animal during each successive
generation. No doubt, as Mr. Wallace has argued,* much
5 “Contributions to the Theory of Natural Selection,’? 1870, p. £12.
THE DESCENT OR ORIGIN OF MAN 99°
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 in-
stance, 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, anda spider its wonderful
web quite as well,* the first time it tries, as when old and
experienced.
To return to our immediate subject: the lower animals,
like man, manifestly feel pleasure and pain, happiness and
misery. Happiness is never better exhibited than by young
animals, such as puppies, kittens, lambs, etc., when playing
together, like our own children. Even insects play together,
as has been described by that excellent observer, P. Huber,’
who saw ants chasing and pretending to bite each other, like
so many puppies.
The 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 mus-
cles to tremble, the heart to palpitate, the sphincters to be
relaxed, and the hair to stand on end. Suspicion, the off-
spring of fear, is eminently characteristic of most wild ani-
mals. It is, I think, impossible to read the account given
by Sir E. Tennent, of the behavior of the female elephants,
used as decoys, without admitting that they intentionally
practice deceit, and well know what they are about. Cour-
age 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 ani-
6 For the evidence on this head, see Mr. J. Traherne Moggridge’s most
interesting work, ‘‘Harvesting Ants and Trap-door Spiders,’’ 1873, pp. 126, 128,
1 “Recherches sur les Mceurs des Fourmis,”? 1810, p. 173.
1v0 THE DESCENT OF MAN
mals 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 Rengger, and Brehm? state that the American
and African monkeys which they kept tame certainly re-
venged 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 ay to the amusement of many bystand-
ers. For long afterward the baboon rejoiced and ee
whenever he saw his victim.
The love of a dog for his master is notorious; as an old
writer quaintly says,’ ‘‘A dog is the only thing on this earth
that luvs you more than he luvs himself.’’
y' 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” has well asked, ‘‘who that reads the touch-
ing instances of maternal affection, related so often of the
women of all nations, and.of the females of all animals, can
doubt that the principle of action is the same in the two
cases?’’ We see maternal 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
8 All the following statements, given on the authority of these two natural-
ists, are taken from Rengger’s “‘Naturgesch. der Sdugethiere von Paraguay,”
1830, s. 41-57, and from Brehm’s “‘Thierleben,’’ B, i. 8. 10-87.
® Quoted by Dr, Lauder Lindsay, in his “Physiology of Mind in the Lower
Animals’’; ‘‘Journal of Mental Science,’ April, 1871, p. 38.
10 “Bridgewater Treatise,’ p. 263.
THE DESCENT OR ORIGIN OF MAN : 101
of her young ones in astream. So intense is the grief of
female monkeys for the loss of their young, that it invari-
ably caused the death of certain kinds kept under confine-
ment by Brehm in North Africa. Orphan monkeys were
always adopted and carefully guarded by the other monkeys,
both males and females. One female baboon had so capa-
cious a heart that she not only adopted young monkeys of
other species, but stole young dogs and cats, which she con-
tinually 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 cer-
tainly 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."* In the
Zoological Gardens, I heard from the keeper that an old
baboon (C., Chacma) had adopted a Rhesus 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 near relatives, for she at once rejected
the Rhesus and adopted both of them. The young Rhesus,
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 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 dis-
liked, as well as other animals, in various ingenious ways.
n A critic, without any grounds (‘‘Quarterly Review,”’ July, 1871, p. 72),
disputes the possibility of this act as described by Brehm, for the sake of dis-
crediting my work. Therefore I tried, and found that I could readily seize
with nly own teeth the sharp little claws of a kitten nearly five weeks old.
\
|
1020 THE DESCENT OF MAN
Most of the more complex emotions are common to the
higher animals and ourselves. Every one has seen how jeal-
ous a dog is of his master’s affection, if lavished on any other
creature; and I have observed the same fact with monkeys.
This shows that animals not only love, but have desire to
be loved. Animals manifestly feel emulation. They love
approbation 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. Sev-
eral observers have stated that monkeys certainly dislike
being laughed at; and they sometimes invent imaginary
offences. In the Zoological Gardens I saw 4 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 humor, 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 tri-
umph, repeating the same manceuvre, and evidently enjoy-
ing 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 Rengger, 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 c”
*
ihe
el,
With
THE DESCENT OR ORIGIN OF MAN 103
instinctive dread which his monkeys exhibited for snakes;
but their curiosity was so great that they could not desist
from occasionally satiating their 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 ac-
cidentally 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,” a liv-
ing turtle, and other new objects were placed in their cages;
for, though at first frightened, they soon approached, han-
dled, 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 ap-
proached, 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 mon-
keys 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
2 T have given a short account of their behavior on this occasion in my
**Rixpression of the Emotions,’ p. 43.
104 THE DESCENT OF MAN
been known to be much alarmed at the first sight of a
turtle. **
The principle of Jmitation is strong in man, and espe-
cially, 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 oth-
ers, at the commencement 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 performed near them.’* Desor’®
has remarked that no animal voluntarily imitates an action
performed by man, until in the ascending scale we come to
monkeys, which are well known to be 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, '* but whether
this can be called voluntary imitation is another question.
Birds imitate the songs of their parents, and sometimes 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 learned to imi-
tate 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 accounts; 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 afterward practiced during his life of thirteen years.
Dureau de la Malle’s dog likewise learned from the kittens
to play with a ball by rolling it about with his forepaws, and
springing on it. A correspondent 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
18 W, OC. L. Martin, “‘Nat. Hist. of Mammalia,’’ 1841, p. 405.
44 Dr, Bateman ‘‘On Aphasia,’’ 1870, p. 110.
18 Quoted by Vogt, ‘‘Mémoire sur les Microcéphales,’’ 1867, p. 168.
16 “The Variation of Animals and Plants under Domestication,’’ vol. i. p. 27.
“Annales des Sc. Nat.’’ (1st Series), tom. xxii, p. 397,
THE DESCENT OR ORIGIN OF MAN 105
learned the same trick, and practiced it ever afterward
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 ap-
proached. 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, if he 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 atten-
tion. If, 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.
1t is almost superfluous to state that animals have excel-
lent Memories for persons and places. A baboon at the Cape
of Gocd Hope, as I have been informed by Sir Andrew
Smith, recognized him with joy after an absence of nine
months. I had a dog who was savage and averse to all
106 THE DESCENT OF MAN
strangers, and I purposely tried his memory after an ab-
sence of five years and two days. I went near the stable
where he lived, and shouted to him in my old manner; he
showed no joy, but instantly followed me out walking, 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* has clearly shown, recog-.
nized 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 recur-
rent 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 results. A poet, as Jean Paul Richter remarks,”
‘‘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 involuntary 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,”° have vivid dreams, and this is shown by their move-
ments and the sounds uttered, we must admit that they pos-
sess some power of imagination. There must be something
special which causes dogs to howl in the night, and espe-
cially during moonlight, in that remarkable and melancholy
manner called baying. All dogs do not do so; and, accord-
18 ‘Teg Mceurs des Fourmis,’’ 1810, p. 150.
19 Quoted in Dr. Maudsley’s ‘‘Physiology and Pathology of Mind,’’ 1868,
pp. 19, 220.
2% Dr. Jerdon, ‘‘Birds of India,” vol. i., 1862, p. xxi. Houzeau says that
his paroquet and canary-birds dreamed: ‘‘Facultés mentales,’’ tom. ii. p. 136.
THE DESCENT OR ORIGIN OF MAN 107
ing to Houzeau,” 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 Reason stands at the summit. Only a few
persons now dispute that animals possess some power of rea-
soning. Animals may constantly be seen to pause, deliber-
ate, 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 unlearned
instincts.” In future chapters we shall see that some ani-
mals extremely low in the scale apparently display a certain
amount of reason. No doubt it is often difficult to distin-
guish 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 continuing to
draw the sledges in a compact body, diverged and separated
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 ex-
perience of each individual, or from the example of the
older and wiser dogs, or from an inherited habit, that is,
from instinct? This instinct 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 Eskimo 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
21 “Pecultés Mentales des Animaux,’? 1872, tom. ii. p. 181.
% Mr. L. H. Morgan’s excellent work on ‘‘The American Beaver,” pub-
lished in 1868, offers a good illustration of this remark. I cannot help thinking,
however, that he goes too far in underrating the power of Instinct.
108 THE DESCENT OF MAN
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,” 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 catch the other fishes,
that he was sometimes completely stunned. The pike went
on thus for three months, but at last learned 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 afterward introduced; so
strongly was the idea of a violent shock associated in his
feeble mind with the attempt on his former neighbors. 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 afterward associate a shock with a window-frame;
but, very differently from the pike, he would probably re-
flect 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 per-
sistent in the one than the other, though the pike often re-
ceived much the more severe injury, can we maintain in the
case of man thata similar difference implies the possession
of a fundamentally different mind?
Houzeau relates™ that, while 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 differ-
ence in the vegetation, and as they were absolutely dry there
%3 *‘Die Bewegungen der Thiere,”’ etc., 1873, p. 11.
% “‘Paculiés Mentales des Animaux,’’ 1872, tom. ii. p. 265,
THE DESCENT OR ORIGIN OF MAN 109
could have been no smell of dampearth. 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 wit-
nessed the same behavior in other animals.
I have seen, as I dare say 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 cur-
rent 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 float-
ing 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 ac-
tions, 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 circumstances has
become associated 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 disappointed; 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.** The same would apply to the elephant and the bear
making currents in the air or water. The savage would cer-
tainly neither know nor care by what law the desired move-
ments were effected; yet his act would be guided by a rude
% Prof. Huxley has analyzed with admirable clearness the mental steps by
which a man, as well as a dog, arrives at a conclusion in a case analogous
to that given in my text. See his article, ‘‘Mr. Darwin’s Critics,’’ in the
“Contemporary Review,”’? Nov. 1871, p. 462, and in his ‘‘Critiques and Es-
says,’’ 1873, p. 279.
110 THE DESCENT OF MAN
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 circumstances 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 association 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 shown by the following actions of American mon-
keys, which stand low in their order. Rengger, 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; afterward 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 han-
dle it with the greatest caution. Lumps of sugar were often
given them wrapped up in paper; and Rengger 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.”
The following cases relate to dogs. Mr. Colquhoun”
winged two wild ducks, which fell on the further side of a
26 Mr. Belt, in his most interesting work, ‘“‘The Naturalist in Nicaragua,”’
1874, p. 119, likewise describes various actions of a tamed Cebus, which, I
think, clearly show that this animal possessed some reasoning power.
27 6*The Moor and the Loch,” p. 45. Col. Hutchinson on ‘‘Dog Break-
ing,’’ 1850, p. 46,
THE DESCENT OR ORIGIN OF MAN wn
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 con-
sidered a moment, then deliberately murdered it by giving
it a severe crunch, and afterward brought away both to-
gether. 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 independ-
ent 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 be-
cause they show how strong their reasoning faculty must
have been to overcome a fixed habit.
I will conclude by quoting a remark by the illustrious
Humboldt. ‘‘The muleteers in South America say, ‘IT will
not give you the mule whose step is easiest, but la mas
racional—the one that reasons best’’’; and, as he adds,
‘‘this popular expression, dictated by long experience, com-
bats 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 endeavor to explain away, by
what appears to be mere verbiage,” all such facts as those
above given.
28 “*Pergonal Narrative,’’ Eng. translat., vol. iii, p. 106.
2 Tam glad to find that so acute a reasoner as Mr. Leslie Stephen (‘‘Dar-
winism and Divinity, Essays on Free-thinking,’’ 1873, p. 80), in speaking of
i
112 THE DESCENT OF MAN
It has, 1 think, now been shown that man and the higher
animals, especially the Primates, have some few instincts in
common. All have the same senses, intuitions, and sensa-
tions—similar passions, affections, and emotions, even the
more complex ones, such as jealousy, suspicion, emulation,
gratitude, and magnanimity; they practice deceit and are
revengeful; they are sometimes susceptible to ridicule, and
even havea sense of humor; they feel wonder and curiosity;
they possess the same faculties of imitation, attention, de-
liberation, choice, memory, imagination, the association of
ideas, and reason, though in very 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 case of man.”
Nevertheless, many authors have insisted that man is di-
vided 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 worth-
less, as their wide difference and number prove the difficulty,
if not the impossibility 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 ani- |
mals, 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, etc.; believes
in God, or is endowed with a conscience. I will hazard a
few remarks on the more important and interesting of
these points.
the supposed impassable barrier between the minds of man and the lower
animals, says, *‘The distinctions, indeed, which have been drawn, seem to us
to rest upon no better foundation than a great many other metaphysical distine-
tions; that is, the assumption that because you can give two things different
‘names, they must therefore have different natures. It is difficult to understand
how anybody who has ever kept a dog or seen an elephant can have any doubts
as to an animal’s power of performing the essential processes of reagoning.’’
30 See ‘‘Madness in Animals,’? by Dr. W. Lauder Lindsay, in ‘‘Journal of
Mental Science,” July, 1871. :
THE DESCENT OR ORIGIN OF MAN 113
Archbishop Sumner formerly maintained” that man
alone is capable of progressive improvement. That he is
capable of incomparably greater and more rapid improve-
ment 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 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 inatrap. They must learn cau-
tion by seeing their brethren caught or poisoned. In North
America, where the fur-bearing animals have long been pur-
sued, 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.”
If we look to successive generations, or to the race, there
is no doubt that birds and other animals gradually both ac-
quire and lose caution in relation to man or other enemies ;*
and this caution is certainly in chief part an inherited habit
or instinct, but in part the result of individual experience.
81 Quoted by Sir C. Lyell, ‘Antiquity of Man,’ p. 497.
82 For additional evidence, with details, see M. Houzeau, ‘“‘Les Facultés
Mentales,’’ tom. ii., 1872, p. 147.
33 See, with respect to birds on oceanic islands, my ‘‘Journal of Researches
during the Voyage of the Beagle,’ 1846, p. 398. ‘‘Origin of Species,”’ 5th
edit., p. 260
714 «THE DESCENT OF MAN
A good observer, Leroy,” 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 jack-
als,*° 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,
-trustworthiness, temper, and probably in general intelli-
gence. The common rat has 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,** 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
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, inde-
pendently 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, according 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 ina state of nature cracks a native fruit,
somewhat like a walnut, with a stone.” Rengger® easily
4 “Tettres Phil. sur intelligence des Animaux,’’ nouvelle édit., 1802, p. 86.
35 See the evidence on this head in chap. i. vol. i, ‘‘On the Variation of
Animals and Plants under Domestication.”’
8 “Proc, Zoolog. Soc.,’? 1864, p. 186.
31 Savage and Wyman in ‘‘Boston Journal of Nat. Hist.,”? vol. iv., 1843-
44, p. 383, ;
%8 “‘Saugethiere von Paraguay,’’ 1830, s. 51-56. .
THE DESCENT OR ORIGIN OF MAN 115
taught an American monkey thus to break open hard palm-
nuts; and afterward, of its own accord, it used stones to
open other kinds of nuts, as well as boxes. It thus also
removed the soft rind of fruit that had a disagreeable flavor.
Another monkey was taught to open the lid of a large box
with a stick, and afterward 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 the other end,
and use it in the proper manner as a lever. The famed
elephants in India are well known to break off branches of
trees and use them to drive away the flies; and this same
act has been observed in an elephant in a state of nature.™
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 em-
ployed as implements; but they are likewise used as weap-
ons. Brehm* states, on the authority of the well-known
traveller, Schimper, that in Abyssinia when the baboons
belonging to one species (@. gelada) descend in troops from
the mountains to plunder the fields, they sometimes en-
counter troops of another species (C. 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 firearms 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 was actually closed for a time against the caravan. It
deserves notice that these baboons thus acted in concert.
Mr. Wallace“ on three occasions saw female orangs, accom-
panied by their young, ‘breaking off branches and the great
spiny fruit of the Durian tree, with every appearance of
4 The ‘Indian Field,’? March 4, 1841.
4 “‘Thierleben,”’ B. i. s. 79, 82.
41 “The Malay Archipelago,” vol. i., 1869, p. 8%.
£16 THE DESCENT OF MAN
rage; causing such a shower of missiles as effectually kept
us from approaching too near the tree.’’ As I have re-
peatedly 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 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 distinction; but there appears to me much truth
in Sir J. Lubbock’s suggestion,** that when primeval man
first used flint-stones for any purpose, he would have acci-
dentally 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 neo-
lithic 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 volcanie
regions where lava occasionally flows through forests. The
anthropomorphous apes, guided probably by instinct, build
for themselves temporary platforms; but as many instincts
4 ‘Primeval Man,’’ 1869, pp. 145, 147.
4# “Prehistoric Times,’’ 1865, p 473, ete,
THE DESCENT OR ORIGIN OF MAN 117
are largely controlled by reason, the simpler ones, such as
this of building a platform, might readily pass into a volun-
tary 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 over its head. In these
several habits we probably see the first steps toward some
of the simpler arts, such as rude architecture and dress, as
they arose among 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, the 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
such 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. If either refers what he perceives with his senses
to a mental concept then so do both.“* When TI 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
“4 Mr. Hookham, in a letter to Prof. Max Miiler, in the “Birmingham
News,’ May, 1873.
118 THE DESCENT OF MAN
any neighboring tree for a squirrel. Now do not these ac-
tions clearly show 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 imagina-
tion, as. shown 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 Bitich-
ner** has remarked, how little can the hard-worked wife of
a degraded Australian savage, who uses very few abstract
words, and cannot count above four, exert her self-con-
sciousness, or reflect on the nature of her own existence.
It is generally admitted that the higher animals possess
memory, 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, etc., 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, etc.;
but who can say at what age this occurs in our young chil-
dren? We see at least that such powers are developed in
children by imperceptible degrees.
That animals retain their mental individuality is unques-
tionable. When my voice awakened a train of old associa-
tions 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
4° “‘Conférences sur la Théorie Darwinienne,”’ French translat., 1869, p. 132.
THE DESCENT OR ORIGIN OF MAN 119
evolutionists, and said, ‘‘IT 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 vacated is contradictory of the utterance of
consciousness, and is therefore false; but it is the teaching
necessitated by evolutionism, consequently the hypothesis
is a false one.’’ *
Language.—This faculty has justly been considered as
one of the chief distinctions between man and the lower ani-
mals. But man, as a highly competent judge, Archbishop
Wakely 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 is so expressed by another.”’ ”
In Paraguay the Cebus azare when excited utters at least six
distinct sounds, which excite in other monkeys similar emo-
tions.*° The movements of the features and gestures of
monkeys are understood by us, and they partly understand
ours, as Rengger and others declare. It is a more remark-
able fact that the dog, since being domesticated, has learned
to bark 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 when starting on a walk with his master;
and the very distinct one of demand or supplication, as
when wishing for a door or window to be opened. Accord-
ing to Houzeau, who paid particular attention to the subject,
the domestic fowl utters at least a dozen significant sounds.”
The habitual use of articulate language is, however,
4% The Rev. Dr. J. M’Cann, ‘‘Anti-Darwinism,’’ 1869, p. 13.
41 Quoted in ‘“‘Anthropological Review,’’ 1864, p. 158.
48 Rengger, ibid., s. 45. awe
49 See my “‘Variation of Animals and Plants under Domestication,’* vol,
. 27,
Pia **Wacultés Mentales des Animaux,’’ tom ii., 1872, pp. 346-349,
120 THE DESCENT OF MAN
peculiar to man; but he uses, in common with the lower
animals, inarticulate cries to express his meaning, aided by
gestures and the movements of the muscles of the face.”
This especially holds good with the more simple and vivid
feelings, which are but little connected with our higher in-
telligence. 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 connecting defi-
nite sounds with definite ideas; for it is certain that some
parrots which have been taught to speak connect unerringly
words with things, and persons with events. The lower
animals differ from man solely in his almost infinitely larger
power of associating together the most diversified sounds
and ideas; and this obviously depends on the high devel-
opment of his mental powers.
As Horne Took, one of the founders of the noble science
51 See a discussion on this subject in Mr, E. B. Tylor’s very interesting
work, ‘‘Researches into the Early History of Mankind,’’ 1865, chaps. ii. to iv.
52 T have received several detailed accounts to this effect. Admiral Sir
J. Sullivan, whom I know to be a careful observer, assures me that an African
parrot, long kept in his father’s house, invariably called certain persons of the
household, as well as visitors, by their names. He said ‘‘Good-morning”’ to
every one at breakfast, and ‘“‘Good-night’’ to each as they left the room
at night, and never reversed these salutations, To Sir J. Sullivan’s father, he
used to add to the ‘‘Good-morning’”’ a short sentence, which was never once
repeated after his father’s death. He scolded violently a strange dog which
came into the room through the open window; and he scolded another parrot
(saying ‘You naughty polly’’) which had got out of its cage, and was eating
apples on the kitchen table. See also, to the same effect, Houzeau on, parrots,
“Facultés Mentales,’’ tom. ii, p. 309. Dr. A. Moschkau informs me that he
knew a starling which never made a mistake in saying in German ‘‘Good-
morning” to persons arriving, and ‘‘Good-by, old fellow,” to those departing.
I could add several other such cases.
THE DESCENT OR ORIGIN OF MAN 121
of philology, observes, language is an art, like brewing or
baking; but writing would have been a better simile. It
certainly is not a true instinct, for every language has to
be learned. It differs, however, widely from all ordinary
arts, for man has an instinctive tendency to speak, as we
see in the babble of our young children; while no child has
an instinctive tendency to brew, bake, or write. Moreover,
no philologist now supposes that any language has been de-
liberately invented; it has been slowly and unconsciously
developed by many steps.** KThe sounds uttered by birds
offer in several respects the nearest analogy to language, for
all the members of the same species utter the same instinc-
tive 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 learned from their parents
or foster-parents. These sounds, as Daines Barrington™ has
proved, ‘‘are no more innate than language is in man.”’
The first attempts to sing ‘‘may be compared to the imper-
fect endeavor in a child to-babble.”” The young males con-
tinue practicing, 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.’’ WNestlings which have
learned the song of a distinct species, as with the canary-
birds educated in the Tyrol, teach and transmit their new
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 provin-
cial dialects,’’ and the songs of allied though distinct species
53 See some good remarks on this head by Prof. Whitney, in his ‘‘Oriental
and Linguistic Studies,’’ 1873, p. 354. He observes that the desire of com-
munication between man is the living force, which, in the development of
language, ‘‘works both consciously and unconsciously; consciously as regards
the immediate end to be attained; unconsciously as regards the further conse-
quences of the act.”’ :
54 Hon. Daines Barrington, in ‘‘Philosoph. Transactions,’’ 1773, p, 262,
See also Dureau de la Malle, in ‘‘Ann. des Sc. Nat.,’’ 3d series, Zoolog., tom.
x. p. 119.
Descent—Vo. I.—6,
122 THE DESCENT OF MAN
may be compared with the languages of distinct races of man.
I have given the foregoing details to show that an instinctive
tendency to acquire an art is not peculiar to man.
With respect to the origin of articulate language, after
having read on the one side the highly interesting works of
Mr. Hensleigh Wedgwood, the Rev. F. Farrar, and Prof.
Schleicher,®* and the celebrated lectures of Prof. Max Miil-
ler, on the other side, I cannot doubt that language owes its
origin to the imitation and modification of various natural
sounds, the voices of other animals, and man’s own instine-
tive 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, trlumph—and would have served as a
challenge to rivals. It is, therefore, probable that the imi-
tation of musical cries by articulate sounds may have given
rise to words expressive of various complex emotions. The
strong tendency in our nearest allies, the monkeys, in micro-
cephalous idiots,** and in the barbarous races of mankind,
to imitate whatever they hear, deserves notice as bearing on
the subject of imitation. Since monkeys certainly under-
stand much that is said to them by man, and’ when wild
utter signal cries of danger to their fellows,” and since
fowls give distinct warnings for danger on the ground, or
5 “On the Origin of Language,”” by H. Wedgwood, 1866. ‘‘Chapters on
Language,’ by the Rev. F. W. Farrar, 1865. These works are most interest-
ing. See also “‘De Ja Phys. et de Parole,’’ par Albert Lemoine, 1865, p. 190.
The work on this subject, by the late Prof. Aug. Schleicher, has been trans-
lated by Dr. Bikkers into English, under the title of ‘‘Darwinism tested by the
Science of Language,’ 1869.
56 Vogt, ‘‘Mémoire sur les Microcéphales,’? 1867, p. 169. With respect to
savages, I have given some facts, in my ‘‘Journal of Researches,” ete., 1845,
. 206.
Pon See clear evidence on this head in the two works so often quoted by
Brehm and Rengger.
ee ere
THE DESCENT OR ORIGIN OF MAN 123
in the sky, from hawks (both, as well as a third ery, intel-
ligible to dogs), may not some unusually wise ape-like
animal have imitated the growl of a beast of prey, and thus
iold his fellow-monkeys the nature of the expected dan-
ger? 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 be-
tween the continued use of language and the development
of the brain has no doubt been far more important. The
mental powers in some early progenitor of man must have
been more highly developed than in 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 while dreaming.” 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 reason to a cer-
tain extent, manifestly without the aid of language. The
intimate connection between the brain, as it is now devel-
oped in us, and the faculty of speech, is well shown by
58 Houzeau gives a very curious account of his observations on this subject
in his ‘‘Facultés Mentales des Animaux,’’ tom, ii. p. 348.
59 See remarks on this head by Dr. Maudsley, ‘‘The Physiology and Pathol-
ogy of Mind,’’ 2d edit., 1868, p. 199.
124 THE DESCENT OF MAN
those curious cases of brain disease in which speech is spe-
cially affected, as when the power to remember substantives
is lost, while 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.” There is
no more improbability in the continued use of the mental
and vocal organs leading to inherited changes in their struc-
ture 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 handwriting is certainly
inherited.” ‘
Several writers, more especially Prof. Max Miiller,” hav
lately insisted that the use of language implies the power of
forming general concepts; and that as no animals are sup-
posed to possess this power, an impossible barrier is formed
between them and man. With respect to animals, I have
already endeavored 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 incredible that they should be able to con-
nect certain sounds with certain general ideas as quickly as
they do, unless such ideas were already formed in their
60 Many curious cases have been recorded. See, for instance, Dr. Bateman
“On Aphasia,’? 1870, pp. 27, 31, 53, 100, ete. Also, ‘Inquiries Concerning
the Intellectual Powers,’? by Dr. Abercrombie, 1838, p. 150.
6 “The Variation of Animals and Plants under Domestication,’’ vol. ii. p. 6.
6 Lectures on ‘‘Mr. Darwin’s Philosophy of Language,’’ 1873.
88 The judgment of a distinguished philologist, such as Prof. Whitney, will
have far more weight on this point than anything that I can say. He remarks
(‘Oriental and Linguistic Studies,’’ 1873, p. 297), in speaking of Bleek’s views:
**Because on the grand scale language is the necessary auxiliary of thought,
indispensable to the development of the power of thinking, to the distinctness
and variety and complexity of cognitions, to the full mastery of consciousness;
therefore he would fain make thought absolutely impossible without speech,
identifying the faculty with its instrument. He might just as reasonably assert
that the human hand cannot act without a tool. With such a doctrine to start
from, he cannot stop short of Miller’s worst paradoxes, that an infant (in fans,
not speaking) is not a human being, and that deaf-mutes do not become pos-
sessed of reason until they learn to twist their fingers into imitation of spoken .
words’? Max Miller gives in italics (‘‘Lectures on Mr, Darwin’s Philosophy
of Languages,’’ 1873, third lecture) the following aphorism: ‘‘There is no
thought without words, as little as there are words without thought,’?
What a strange definition must here be given to the word thought!
THE DESCENT OR ORIGIN OF MAN 125
minds. The same remark may be extended to the more
intelligent animals; as Mr. Leslie Stephen observes, ‘A
dog frames a general concept of cats or sheep, and knows
the corresponding words as well as a philesopher. And
the capacity to understand is as good a proof of vocal in-
telligence, though in an inferior degree, as the capacity to
speak.’’ ;
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 antenna,
as shown by Huber, who devotes a whole chapter to their
language. We might have used our fingers as efficient in-
struments, 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, while thus employed,
would have been a serious inconvenience. As all the higher
mammals possess vocal organs, constructed on the same gen-
eral 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.*° 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 organs, which with long-continued practice might
have been used for speech, although not thus used, is paral-
leled 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.* If it be asked why apes have not
6 ‘*Hssays on Free-thinking,’’ etc., 1873, p. 82. :
65 See some good remarks to this effect by Dr. Maudsley, ‘“‘The Physiology
and Pathology of Mind,’’ 1868, p. 199.
86 Macgillivray, ‘‘Hist. of British Birds,”’ vol. ii., 1839, p. 29. An excellent
observer, Mr. Blackwall, remarks that the magpie learns to pronounce single
126 THE DESCENT OF MAN
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, consider-
ing our ignorance with respect to the successive stages of
development through which each creature has passed.
The formation of different languages and of distinct spe-
cies, and the proofs that both have been developed through
a gradual process, are curiously parallel.” But we can trace
the formation of many words further back than that of spe-
cies, 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 analo-
gies 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 rudiments, both in lan-
guages and in species, is still more remarkable. The letter
m in the word am, means J; so that in the expression J 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 artificially 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 birthplaces. Distinct lan-
guages may be crossed or blended together. We see vari-
words, and even short sentences, more readily than almost any other British
bird; yet, as he adds, after long and closely investigating its habits, he has
never known it in a state of nature, display any unusual capacity for imitation.
‘*Researches in Zoology,’’ 1834, p. 158.
61 See the very interesting parallelism between the development of species
and languages, given by Sir C, Lyell in ‘‘The Geolog. Evidences of the Antiquity
of Man,’’ 1863, chap. xxiii.
88 See remarks to this effect by the Rev. F. W. Farrar, in an interesting arti-
ele entitled ‘‘Philology and Darwinism,’’ in ‘‘Nature,’’ March 24, 1870, p, 528,
THE DESCENT OR ORIGIN OF MAN 127
ability in every tongue, and new words are continually
cropping up; but as there is a limit to the powers of the
memory, single words, like whole languages, gradually be-
come extinct. As Max Miiller® has well remarked: “A
struggle for life is constantly going on among 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 cer-
tain favored words. in the struggle for existence is natural
selection.
The perfectly regular and wonderfully complex construc-
tion of the languages of many barbarous nations has often
been advanced as a proof, either of the divine origin of these
languages or of the high art and former civilization of their
founders. Thus F. von Schlegel writes: ‘‘In those lan-
guages which appear to be at the lowest grade of intellec-
tual culture, we frequently observe a very high and elabo-
rate degree of art in their grammatical structure. This is
especially the case with the Basque and the Lapponian, and
many of the American languages.’’” But it is assuredly
an error to speak of any language as an art, in the sense
of its having been elaborately and methodically formed.
Philologists now admit that conjugations, declensions, etc.,
originally existed as distinct words, since joined together;
and as such words express the most obvious relations be-
tween 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 show how easily we may err: A Crinoid
sometimes consists of no less than 150,000 pieces of shell,”
6 “*Nature,’’? Jan. 6, 1870, p. 257.
Quoted by C. 8. Wake, ‘‘Chapters on Man,” 1868, p, 101,
1 Buckland, ‘‘Bridgewater Treatise,”’ p. 411,
128 THE DESCENT OF MAN
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 oppo-
site sides of the body. He justly considers the differentia-
tion and specialization of organs as the test of perfection.
So with languages; the most symmetrical and complex
ought not to be ranked above irregular, abbreviated, and
bastardized languages, which have borrowed expressive
words and useful forms of construction from various con-
quering, 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.” Nor, as we have seen, does
the faculty of articulate speech in itself offer any insuper-
able 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 colors, 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 colors
before the female, while 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 every-
where 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 gayly colored
objects; and this shows that they must receive some kind
of pleasure from the sight of such things. With the great
® See some good remarks on the simplification of languages, by Sir J. Lub-
bock, ‘‘Origin of Civilization,’’? 1870, p. 278.
THE DESCENT OR ORIGIN OF MAN 129
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 beauti-
ful colors, the ornaments and voices of their male partners,
all the labor and anxiety exhibited by the latter in display-
ing their charms before the females would have been thrown
away; and this it is impossible to admit. Why certain
bright colors should excite pleasure cannot, I presume, be
explained, any more than why certain flavors 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 cadences
areagreeable. But besides this, sounds frequently recurring
at irregular intervals are highly disagreeable, as every one
will admit who has listened at night to the irregular flap-
ping of arope 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 orna-
ments; and they have been developed through sexual se-
lection 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 colors, 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 xsthetic faculty was not so highly developed as
180 THE DESCENT OF MAN
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 landscape, 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 ca-
pricious changes of customs and fashions. I have alluded
to this point, because a recent writer” has oddly fixed on
Caprice ‘‘as one of the most remarkable and typical differ-
ences between savages and brutes.’’ But not only can we
partially understand how it is that man is from various con-
flicting influences rendered capricious, but that the lower
animals are, as we shall hereafter see, likewise capricious
in their affections, aversions, and sense of beauty. There
is also reason to suspect that they love novelty for its
own sake.
Belief in ee Raia 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 long resided with savages, that numerous
races have existed, and still exist, who have no idea of one
or more gods, and who have no words in their languages to
express such an idea.“ The question is of course wholly
distinct from that higher one, whether there exists a Creator
and Ruler of the universe; and this has been answered in
73 “The Spectator,’’ Dec. 4, 1869, p. 1430.
4 See an excellent article on this subject by the Rev. F. W. Farrar, in the
“Anthropological Review,’’ Aug. 1864, p. ecxvii. For further facts see Sir J.
Lubbock, ‘‘Prehistoric Times,’ 2d edit., 1869, p. 564; and especially the chap-
ters on Religion in his “Origin of Civilization,” 1870.
THE DESCENT OR ORIGIN OF MAN | 131
the affirmative by some of the highest intellects that have
ever existed. ¥
If, however, we include under the term ‘‘religion’’ the
belief in unseen or spiritual agencies, the case is wholly
different; for this belief seems to be universal with the
less civilized races. Nor is it difficult to comprehend how
it arose. As soon as the important faculties of the imag-
ination, 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 exist-
ence. As Mr. M‘Lennan’ has remarked, ‘‘Some explana-
tion of the phenomena of life, a man must feign for him-
self; 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
shown, 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
‘tthe soul of the dreamer goes out on its travels, and comes
home with a remembrance of what it has seen.’’ ° But until
7 “‘The Worship of Animals and Plants,’ in the ‘‘Fortnightly Review,”
Oct. 1, 1869, p. 422.
76 Tylor, ‘‘Early History of Mankind,’’ 1865, p. 6. See also the three strik-
ing chapters on the Development of Religion, in Lubbock’s ‘‘Origin of Civiliza-
tion,’? 1870. In a like manner, Mr. Herbert Spencer, in his ingenious essay in
the ‘‘Fortnightly Review’? (May 1, 1870, p. 535), accounts for the earliest forms
of religious belief throughout the world, by man being led, through dreams,
shadows, and other causes, to look at himself as a double essence, corporeal
and spiritual. As the spiritual being is supposed to exist after death and to be
powerful, it is propitiated by various gifts and ceremonies, and its aid invoked.
He then further shows that_names or nicknames given from some animal or
other objett to the early progenitors or founders of a tribe are supposed after
a long interval to represent the real progenitor of the tribe; and such animal or
object is then naturally believed still to exist as a spirit, is held sacred, and
worshipped as a god. Nevertheless, I cannot but suspect that there is a still
132 THE DESCENT OF MAN
the faculties of imagination, curiosity, reason, etc., 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 a dog.
X¥ 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 occasionally 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 say-
ages 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 Fue-
gians appear to be, in this respect, in an intermediate con-
dition, 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 retribu-
tive punishment for wasting human food. So again he re-
lated 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
aGod, or practiced 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 remark-
earlier and ruder stage, when anything which manifests power or movement is
thought to be endowed with some form of life, and with mental faculties analo-
gous to our own.
THE DESCENT OR ORIGIN OF MAN 133
able, as with savages the belief in bad spirits is far more
common than that in good ones.
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,’
fear, reverence, gratitude, hope for the future, and perhaps
other elements. No being could éxperience so complex an
emotion until advanced in his intellectual and moral facul-
ties to at least a moderately high level. Nevertheless, we
see some distant approach to this state of mind in the deep
love of a dog for his master, associated with complete sub-
mission, some fear, and perhaps other feelings. The behay-
ior 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 toward their fellows. In the lat-
ter case the transports of joy appear to be somewhat less,
and the sense of equality is shown in every action. Prof.
Brauback goes so far as to maintain that a dog looks on his
master as on a god.”
The same high mental faculties which first led man
to believe in unseen spiritual agencies, then in fetichism,
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, etc.—yet
it is well occasionally to reflect on these superstitions, for
they show us what an infinite debt of gratitude we owe to
the improvement of our reason, to science, and to our accumu-
lated knowledge. As Sir J. Lubbock” has well observed,
™ See an able article on the ‘‘Physical Elements of Religion,’’ by Mr. L.
Owen Pike, in ‘‘Anthropolog, Review,’’ April, 1870, p. lxiii.’
7 “Religion, Moral, etc., der Darwin’schen Art-Lehre,’’ 1869, s. 53. Itis
said (Dr. W. Lauder Lindsay, “Journal of Mental Science,” 1871, p. 43) that
Bacon long ago, and the poet Burns, held the same notion.
79 ‘Prehistoric Times,’ 2d edit., p. 571. In this work (p. 571) there will
be found an excellent account of the many strange and capricious customs of
savages,
1
¥
134 THE DESCENT OF MAN
“it is not too much to say that the horrible dread of unknown
evil hangs like a thick cloud over savage life, and imbitters
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.
CHAPTER IV
COMPARISON OF THE MENTAL POWERS OF 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
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? remarks,
“has a rightful supremacy over every other principle of
~ human action’; it is summed up in that short but imperi-
ous word ought, so full of high significance. It is the most
noble of all the attributes of man, leading him without a
moment’s hesitation 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
greatcause. 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
| FULLY subscribe to the judgment of those writers' who
1 See, for instance, on this subject, Quatrefages, “Unité de l’Espéce Hu-
mauine,’’ 1861, p. 21, ete.
2 “Dissertation on Ethical Philosophy,’’ 1837, p. 231, ete.
THE DESCENT OR ORIGIN OF MAN 135
not always obedience; before whom all appetites are dumb,
however secretly they rebel; whence thy original ?”’ *
This great question has been discussed by many writers*
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 independent 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,® the parental and filial affec-
tions 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, first, the social instincts lead an animal to take pleas-
ure in the society of its fellows, to feel a certain amount of
8 ‘‘Metaphysics of Ethics,” translated by J. W. Semple, Edinburgh, 1836,
. 136, 5
ae Mr. Bain gives a list (‘‘Mental and Moral Science,’’ 1868, pp. 543-725)
of twenty-six British authors who have written on this subject, and whose
names are familiar to every reader; to these, Mr, Bain’s own name, and those
of Mr. Lecky, Mr. Shadworth Hodgson, Sir J. Lubbock, and others, might be
added.
5 Sir B. Brodie, after observing that man is a social animal (‘‘Psychological
Inquiries,’’ 1854, p. 192), asks the pregnant question, ‘‘Ought not this to settle
the disputed question as to the existence of a moral sense?’’ Similar ideas
have probably occurred to many persons, as they did long ago to Marcus Au-
relius. Mr. J. S. Mill speaks, in his celebrated work, ‘‘Utilitarianism’’ (1864,
pp. 45, 46), of the social feelings as a “‘powerful natural sentiment,’’ and as
“the natural basis of sentiment for utilitarian morality.”? Again he says, ‘‘Like
the other acquired capacities above referred to, the moral faculty, if not a part
of our nature, is a natural outgrowth from it; capabie, like them, in a certain
small degree, of springing up spontaneously.’? But in opposition to all this, he
also remarks, ‘‘if, as is my own belief, the moral feelings are not innate, but
acquired, they are not for that reason less natural.’ It is with hesitation that
I venture to differ at all from se profound a thinker, but it can hardly be dis-
puted that the social feelings are instinctive or innate in the lower animals; and
why should they not be so in man? Mr. Bain (see, for instance, “‘The Emo-
tions and the Will,”’? 1865, p. 481) and others believe that the moral sense is
acquired by each individual during his lifetime. On the general theory of evo-
lution, this is at least extremely improbable. The ignoring of all transmitted
mental qualities will, as it seems to me, be hereafter judged as a most serious
blemish in the works of Mr. Mill.
136 THE DESCENT OF MAN
sympathy with them, and to perform various services for
them. The services may be of a definite and evidently in-
stinctive 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 feel-
ing of dissatisfaction, or even misery, which invariably re-
sults, 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 behind it a very vivid impression. It
is clear that many instinctive desires, such as that of hun-
ger, 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, the common opinion
how each member ought to a for the public good would
naturally become in a paramount degree the guide to action.
~ But it should be borne in mind that, however great weight
we may attribute to public opinion, our regard for the ap-
probation and disapprobation of our fellows depends on
sympathy, which, as we shall see, forms an essential par’.
of the social instinct, and is indeed its foundation-stont.
_ Lastly, habit, in the individual, would ultimately play a
very important part in guiding the conduct of each mem-
ber; for the social instinct, together with sympathy, is, like
any other instinct, greatly strengthened by habit, and so
consequently would be obedience to the wishes and judg-
ment of the community. These several subordinate propo-
sitions must now be discussed, and some of them at con-
siderable length.
It may be well first to premise that I do not wish to
THE DESCENT OR ORIGIN OF MAN 187
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 ob-
jects, so they might have a sense of right and wrong,
though led by it to follow widely different lines of con-
duct. 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 sirive to kill their fertile
daughters; and no one would think of interfering.*° Never-
theless, the bee, or any other social animal, would gain in
our supposed case, as it 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 en-
during instincts, and others less strong or enduring; so that
there would often be a struggle as to which impulse should
be followed; and satisfaction, dissatisfaction, 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,
6 Mr. H. Sidgwick remarks, in an able discussion on this subject (the
**Academy,”” June 15, 1872, p. 231), ‘‘a superior bee, we may feel sure, would
aspire to a milder solution of the population question.’? Judging, however,
from the habits of many or most savages, man solves the problem by female
infanticide, polyandry, and promiscuous intercourse; therefore it may well be
doubted whether it would be by a milder method. Miss Cobbe, in commenting
(‘Darwinism in Morals,*? **Theological Review,”’ April, 1872, pp. 188-191) on
the same illustration, says, the principles of social duty would be thus reversed ;
and by this, I presume, she means that the fulfilment of a social duty would tend
to the injury of individuals; but she overlooks the fact, which she would doubt-
less admit, that the instincts of the bee have been acquired for the good of the
community. She goes so far as to say that if the theory of ethics advocated in
this chapter were ever generally accepted, ‘I cannot but believe that in the hour
of their triumph would be sounded the knell of the virtue of mankind!’ It is
to be hoped that the belief in the permanence of virtue on this earth is not held
by many persons on so weak a tenure.
188 YHE DESCENT OF MAN
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 shows the same feeling in his strong
Jove for the dog, which the dog returns with interest.
Every one must have noticed how miserable horses, dogs,
sheep, etc., are when separated from their companions,
and what strong mutual affection the two former kinds, at
least, show 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
many important ways. The most common mutual service
in the higher animals is to warn one another of danger by
means of the united senses of all. Every sportsman knows,
as Dr. Jaeger remarks,’ how difficult it is to approach ani-
mals in a herd or troop. Wild horses and cattle do not, 1
believe, make any danger-signal; but the attitude of any
one of them who first discovers an enemy warns the others.
Rabbits stamp loudly on the ground with their hind feet as
a signal; sheep and chamois do the same with their forefeet,
uttering likewise a whistle. Many birds, and some mam-
mals, post sentinels, which in the case of seals are said®
generally to be the females. The leader of a troop of
monkeys acts as the sentinel, and utters cries expressive
both of danger and of safety.° Social animals perform
7 “Die Darwin’sche Theorie,’ s. 101.
8 Mr. R. Brown in ‘‘Proc. Zoolog. Soc.,’? 1868, p. 409.
® Brehm, ‘‘Thierleben,”’ B, i., 1864, 8.62, 79, For the case of the monkeys
extracting thorns from each other, see s. 54. With respect to the Hamadryas
turning over stones, the fact is given (s. 76) on the evidence of Alvarez, whose
observations Brehm thinks quite trustworthy. or the cases of the old male
beboons attacking the dogs, see s. 79; and with respect to the eagle, s. 56,
THE DESCENT OR ORIGIN OF MAN 139
many little services for each other; 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 Cercopithecus griseo-viridis 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 bur.
Animals also render more important services to one
another; thus wolves and some other beasts of prey hunt
in packs, and aid one another in attacking their victims.
Pelicans fish in concert. The Hamadryas baboons turn
over stones to find insects, etc.; and when they come to a
large one, as many as can stand round turn it over together
and share the booty. Social animals mutually defend each
other. Bull bisons in North America, when there is danger,
drive the cows and calves into the middle of the herd, while
they defend the outside. I shall also in a future chapter
give an account of two young wild bulls at Chillingham at-
tacking 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 immedi-
ately 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 baboons had reascended the heichis, ex-
cepting a young one, about six months old, who, loudly
calling for aid, climbed on a block of rock, and was sur-
rounded. Now one of the largest 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;
140 YHE DESCENT OF MAN
it cried loudly for assistance, upon which the other members
of the troop, with much uproar, rushed to the rescue, sur-
rounded the eagle, and pulled out so many feathers that he”
no longer thought of his prey, but only how to escape.
This eagle, as Brehm remarks, assuredly would never again
attack a single monkey of a troop.”
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 sympathize in the pains
and pleasures of others, is more doubtful, especially with
respect to pleasures. Mr, Buxton, however, who had ex-
cellent means of observation,” states that his macaws, which
lived free in Norfolk, took ‘‘an extravagant interest’’ in a
pair with a nest; and whenever the female left it, she was
surrounded by a troop ‘‘screaming horrible acclamations in
her honor.’’ 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; apparently, how-
ever, 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 conduct is not much worse than that of the
Nerth Amevican Indians, who leave their feeble comrades
to perish o« the plains; or the Fijians, who, when their
parents get old, or fall ill, bury them alive.”
© Mr, Belt gives the case of a spider monkey (Ateles) in Nicaragua, which
was heard screaming for nearly two hours in the forest, and was found with an
eagle perched close by it. The bird apparently feared to attack as long as it
remained face to face; and Mr. Belt believes, from what he has seen of the
habits of these monkeys, that they protect themselves from eagles by keeping
two or three together. ‘‘The Naturalist in Nicaragua,” 1874, p. 118,
H ‘Annals and Mag. of Nat. Hist.,”” November, 1868, p. 382.
2 Sir J. Lubbock, ‘‘Prehistoric Times,” 2d edit. p. 446.
THE DESCENT OR ORIGIN OF MAN 14
Many animals, however, certainly sympathize with each
other’s distress or danger. This is the case even with birds.
Captain Stansbury” 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 hiscompanions. Mr. Blyth,
as he informs 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 development of any special instinct."
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 surest sign
of kind feeling in a dog.
It 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’ 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 vive 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 showed me
some deep and scarcely healed wounds on the nape of his
own neck, inflicted on him, while kneeling on the floor, by
18 As quoted by Mr. L. H. Morgan, “The American Beaver,’’ 1868, p. 272.
Captain Stansbury also gives an interesting account of the manner in which a
very young pelican, carried away by a strong stream, was guided and encour-
aged in its attempts to reach the shore by half a dozen old birds.
14 As Mr. Bain states, ‘‘effective aid to a sufferer springs from sympathy
r’?: ‘Mental and Moral Science,’ 1868, p. 245.
% **Thierleben,’’ B. i. s. 85.
142 THE DESCENT OF MAN
a fierce baboon. The little American monkey, who was a
warm friend of this keeper, lived in the same large com-
partment, 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 dis-
tracted 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 quali-
ties connected with the social instincts, which in us would
be called moral; and l agree with Agassiz** 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’’
remarks, they will refrain from stealing food in the absence
of their master. They have long been accepted as the very
type of fidelity and obedience. But the elephant is likewise
very faithful to his driver or keeper, and probably considers
him as the 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 circum-
stances 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 wonder-
ful proof of noble fidelity.*®
All animals living in a body, which defend themselves
or attack their enemies in concert, must indeed be in some
degree faithful to one another; and those that follow a
leader must be in some degree obedient. When the ba-
16 ‘Ne l’Espéce et de la Classe,’’ 1869, p. 97.
1 “Nie Darwin’sche Art-Lehre,’’ 1869, s. 54,
8 See also Hooker’s ‘‘Himalayan Journals,”’ vol. ii., 1854, p, 333,
THE DESCENT OR ORIGIN OF MAN 148
boons in Abyssinia’ 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 South
Africa, says,” that they cannot endure even a momentary
separation from the herd. They are essentially slavish, and
accept the common determination, seeking no better lot than
to be led by any one ox who has enough self-reliance to
accept the position. The men who break in these animals
for harness watch assiduously for those who, by grazing
apart, show a self-reliant disposition, 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 lookout 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 experi-
ence in performing 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, while some other kinds of dogs, as I have
witnessed, utterly disregard foxes. What a strong feeling
of inward satisfaction must impel a bird, so full of activity,
to brood day after day over her eggs. Migratory birds are
quite miserable if stopped from migrating; perhaps they
enjoy starting on their long flight; but it is hard to believe
19 Brehm, ‘‘Thierleben,’’ B. i. 8. 76. . ; ;
20 See his extremely interesting paper on ‘‘Gregariousness in Cattle, and in
Man,’’ ‘‘Macmillan’s Mag.,’? Feb. 1871, p. 353.
144 THE DESCENT OF MAN
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 toward special enemies. No one, I presume,
can analyze the sensations of pleasure or pain. In many
instances, however, it is probable that instincts are persist-
ently 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 erroneous. A\l-
though a habit may be blindly and implicitly followed, inde-
pendently of any pleasure or pain felt at the moment, yet if
it be forcibly and abruptly checked, a vague sense of dissatis-
faction is generally experienced.
It has often been assumed that animals were in the first
place rendered social, and that they feel as a consequence
uncomfortable when separated from each other, and com-
fortable while together; but it is a more probable view that
these sensations were first developed, in order that those
animals which would profit by living in society should be
induced to live together, in the same manner as the sense
of hunger and the pleasure of eating were, no doubt, first
acquired in order to induce animals to eat. The feeling
of pleasure from society is probably an 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; and this extension may be attributed in part to
habit, but chiefly to natural selection. Wath those animals
which were benefited by living in close association, the indi-
viduals which took the greatest pleasure in society would
best escape various dangers; while those that cared least for
THE DESCENT OR ORIGIN OF MAN 145
their comrades, and lived solitary, would perish in greater
numbers. With respect to the origin of the parental and
filial affections, which apparently lie at the base of the social
instincts, we know not the steps by which they have been
gained; but we may infer that it has been to a large extent
through natural selection. So it has almost certainly 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 rela-
tions 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.
y 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 mas-
ter. Adam Smith formerly argued, as has Mr. Bain re-
cently, that the basis of sympathy lies in our strong reten-
tiveness of former states of pain or pleasure. Hence, ‘‘the
sight of another person enduring hunger, cold, fatigue, re-
vives in us some recollection of these states, which are pain-
ful 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." But I cannot
1 See the first and striking chapter in Adam Smith’s ‘‘Theory of Moral
Sentiments,’’ Also Mr. Bain’s ‘‘Mental and Moral Science,”’ 1868, pp. 244 and
275-282. Mr. Bain states, that “‘sympathy is, indirectly, a source of pleasure
to the sympathizer’; and he accounts for this through reciprocity. He re-
marks that ‘‘the person benefited, or others in his stead, may make up, by
sympathy and good offices returned, for all the sacrifice.” But if, as appears
to be the case, sympathy is strictly an instinct, its exercise would give direct
pleasure, in the same manzer as the exercise, as before remarked, of almost
every other instinct.
Descent—Von. L—}
146 THE DESCENT OF MAN
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, independ-
ently of love, would suffice to call up in us vivid recollec-
tions and associations. The explanation may lie in the fact
that, with all animals, sympathy is directed solely toward
the members of the same community, and therefore toward
known and more or less beloved members, but not to all
the individuals of the same species. This fact is not more
surprising 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 mankind, selfishness, experience, and
imitation probably add, as Mr. Bain has shown, to the power
of sympathy; for we are led by the hope of receiving good
in return to perform acts of sympathetic kindness to others;
and sympathy is much strengthened by habit. In however
complex a manner this feeling may have originated, as it is
one of high importance to all those animals which aid and
defend one another, it will have been increased through
natural selection; for those communities which included the
greatest number of the most sympathetic 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 been 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, therefore, have been directly acquired.
On the other hand, the habit followed by the males of some
social animals of defending the community, and of attacking
their enemies or their prey in concert, may perhaps have
originated from mutual sympathy; but courage, and in most
THE DESCENT OR ORIGIN OF MAN 147
cases strength, must have been previously acquired, proba-
bly througl natural selection.)
Of the various instincts and habits, some are much
stronger than others; that is, some either give more pleas-
ure in their performance, and more distress in their preven-
tion, 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 in-
stincts, or between an instinct and some habitual disposi-
tion; 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 pup-
pies and for her master—for she may be seen to slink away
to them, as if half-ashamed of not accompanying her mas-
ter. But the most curious instance known to me of one in-
stinct getting the better of another is the migratory instinct
conquering the maternal instinct. The former is wonder-
fully 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 continue to exist, and thus unin-
tentionally 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. Nevertheless, the migra-
tory instinct is so powerful, that late in the autumn swal-
lows, house-martins, and swifts frequently desert their ten-
der young, leaving them to perish miserably in their nests.”
2 This fact, the Rev. L. Jenyns states (see his edition of “‘White’s Nat,
Hist. of Selborne,’’ 1853, p. 204), was first recorded by the illustrious Jenner,
in ‘‘Phil. Transact.,’’? 1824, and has since been confirmed by several observers,
especially by Mr. Blackwall. This latter careful observer examined, late in the
autumn, during two years, thirty-six nests; he found that twelve contained
young dead birds, five contained eggs on the point of being hatched, and three,
eggs not nearly hatched. Many birds, not yet old enough for a prolonged
148 THE DESCENT OF MAN
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 per-
sistence 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 confinement 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 in-
“habiting 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 never extend to all
the individuals of the same species. Judging from the anal-
ogy 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 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
flight, are likewise deserted and left behind. See Blackwall, ‘‘Researches in
Zoology,”? 1834, pp. 108, 118. For some additional evidence, although this is
not wanted, see Leroy, ‘‘Lettres Phil.,”’ 1802, p. 21%. For swifts, Gould’s
“Introduction to the Birds of Great Britain,’’ 1823, p. 5. Similar cases have
been observed in Canada by Mr. Adams; ‘‘Pop. Science Review,”’ July, 1873,
p- 283. = ars —
a 2
THE DESCENT OR ORIGIN OF MAN 149
remote period some degree of instinctive love and sympathy
for his fellows. We are indeed all conscious that we do pos-
sess 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. As man is a social animal, it is almost certain
that he would inherit a tendency to be faithful to his com-
rades, and obedient to the leader of his tribe, for these quali-
ties are common to most social animals. He would conse-
quently possess some capacity for self-command. He would
from an inherited tendency be willing to defend, in concert
with others, his fellow-men; and would be ready to aid them
in any way which did not too greatly interfere with his own
welfare or his own strong desires.
The social animals which stand at the 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 im-
pulse, 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 shown,™ the love of praise and the strong feeling
of glory, and the still stronger horror of scorn and infamy,
“fare due to the workings of sympathy.’’ Consequently man
would be influenced in the highest degree by the wishes,
approbation, and blame of his fellow-men, as expressed by
°3 Hume remarks (‘‘An Inquiry’ Concerning the Principles of Morals,’’ edit.
of 1751, p. 132), ‘‘There seems a necessity for confessing that the happiness
and misery of others are not spectacles altogether indifferent to us, but that
the view of the former... communicates a secret joy; the appearance
of the latter . . . throws a melancholy damp over the imagination.”’
24 “Mental and Moral Science,’’ 1868, p. 254.
150 THE DESCENT OF MAN
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 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
—Iam the supreme judge of my own conduct, and, in the
words of Kant, I will not in my own person violate the dig-
nity of humanity.
The more enduring Social Instincts conquer the less per-
sistent 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?
It is evident, in the first place, that with mankind the
instinctive impulses have different degrees of strength; a
savage will risk his own life to save that of a member of
the same community, but will be wholly indifferent about a
stranger; a young and timid mother, urged by the maternal
instinct, will, without a moment’s hesitation, run the great-
est 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, filled with
courage and sympathy, has disregarded the instinct of self-
preservation, and plunged at once into a torrent to save a
THE DESCENT OR ORIGIN OF MAN 151
drowning man, though a stranger. In this case man is im-
pelled 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.
{am aware that some persons maintain that actions per-
formed impulsively, as in the above cases, do not come
under the dominion of the moral sense, and cannot be called
moral. They 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.” As far as
exalted motives are concerned, many instances have been
recorded of savages, destitute of any feeling of general be-
nevolence toward mankind, and not guided by any religious
motive, who have deliberately sacrificed their lives as pris-
oners,”* rather than betray their comrades; and surely their
conduct ought to be considered as moral. As far as deliber-
ation and the victory over opposing motives are concerned,
animals may be seen doubting between opposed instincts, in
rescuing their offspring or comrades from danger; yet their
actions, though done for the good of others, are not called
%5 T refer here to the distinction between what has been called material and
formal morality. I am glad to find that Prof. Huxley (‘‘Critiques and Ad-
dresses, ’’ 1873, p. 287) takes the same view on this subject as Ido. Mr. Leslie
Stephen remarks (‘‘Essays on Free-thinking and Plain Speaking,’’ 1873, p. 83),
“The metaphysical distinction between material and formal morality is as
irrelevant as other such distinctions.”’ ;
% I have given one such case, namely, of three Patagonian Indians who
preferred being shot, one after the other, to betraying the plans of their com-
panions in war (‘‘Journal of Researches,’’ 1845, p. 103).
152 THE DESCENT OF MAN
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 of approving or disapproving of them. We
have no reason to suppose that any of the lower animals
have this capacity; therefore, when a Newfoundland dog
drags a child out of the water, or a monkey faces danger
to rescue its comrade, or takes 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 per-
formed deliberately, after a struggle with opposing 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 corresponding 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-preserva-
tion, hunger, lust, vengeance, ete. Why then does man re-
gret, 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 ani-
THE DESCENT OR ORIGIN OF MAN 153
mals. 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 inces-
santly 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 com-
munity, 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 sym-
pathy 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 fundamental 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 the 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 possession is generally a weaker feeling
than the desire: many a thief, if not a habitual one, after
success has wondered why he stole some article.”
21 Enmity or hatred seems also to be a highly persistent feeling, perhaps
more so than any other that can be named. Envy is defined as hatred of
another for some excellence or success; and Bacon insists (Essay ix.), ‘‘Of all
other affections envy is the most importune and continual. og Dogs are very apt
to hate both strange men and strange dogs, especially if they live near at hand,
but do not belong to the same family, tribe, or clan; this feeling would thus
154 THE DESCENT OF MAN
A man cannot prevent past impressions often repassing
through his mind; he will thus be driven to make a com-
parison 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 blama-
ble. 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 balked 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 in-
stinct 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 be-
come restless, are noisy, and congregate in flocks. While
the mother-bird is feeding, or brooding over her nestlings,
the maternal instinct is probably stronger than the migra-
tory; but the instinct which is the more persistent 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 migratory
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
seem to be innate, and is certainly a most persistent one. It seems to be the
complement and converse of the true social instinct. From what we hear of
savages, it would appear that something of the same kind holds good with
them. If this be so, it would be a small step in any one to transfer such feel-
ings.to any member of the same tribe if he had done him an injury and had
become his enemy. Nor is it probable that the primitive conscience would re-
proach a man for injuring his enemy: rather it would reproach him if he had not
revenged himself. To do good in return for evil, to love your enemy, is a height
of morality to which it may be doubted whether the social instincts would, by
themselves, have ever led us. It is necessary that these instincts, together
with sympathy, should have been highly cultivated and extended by the aid of
reason, instruction, and the love or fear of God, before any such golden rule
would ever be thought of and obeyed.
THE DESCENT OR ORIGIN OF MAN 155
through her mind, of her young ones perishing in the bleak
north from cold and hunger.
At the moment of action man will no doubt be apt to
follow the stronger impulse; and though this may occasion-
ally 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 differ-
ently for the future; and this is conscience; for conscience
looks backward, 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 the 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 féeling of sympathy, and on his own capacity
for reasoning out the remote consequences of his acts. An-
other 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. Sev-
eral 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. ButI can see little force in this objec-
tion. My critics do not define what they mean by remorse,
and I can find no definition implying more than an over-
‘whelming sense of repentance. Remorse 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
156 THE DESCENT OF MAN
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 Hindu, it 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 re-
morse. Dr. Landor acted as a magistrate in West Australia,
and relates” that a native on his farm, after losing one of his
wives from disease, came and said that ‘the was 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 some
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 inexorable,
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, ex-
cepting 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
28 ‘Insanity in Relation to Law’’; Ontario, United States, 1871, p. 14.
THE DESCENT OR ORIGIN OF MAN 157
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.’’** We may,
therefore, reject the belief, lately insisted on by some writ-
ers, that the abhorrence of incest is due to our possessing a
special God-implanted conscience. On the whole it is intel-
ligible that a man urged by so powerful a sentiment as re-
morse, 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 sympathies and instincts, including
his feeling for the judgment of his fellows. The still hun-
gry 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 comes to feel, through acquired and perhaps inherited
habit, that it is best for him to obey his more persistent im-
pulses. The imperious word ought seems merely to imply
the consciousness of the existence of a rule of conduct, how-
ever 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. X
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,
9 FB, Tylor in ‘Contemporary Review,” April, 1873, p. 707.
158 THE DESCENT OF MAN
it would meet with their disapprobation; and few are so des-
titute of sympathy as not to feel discomfort when this is
realized. If he has no such sympathy, and if his desires
leading to bad actions are at the time strong, and when re-
called are not overmastered by the persistent social instincts
and the judgment of others, then he is essentially a bad
man; 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
social 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 necessary 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 as-
suredly 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 fal-
ulty in mankind. The virtues which must be practiced, at
least generally, by rude men, so that they may associate in
a body, are those which are still recognized as the most
important. But they are practiced almost exclusively in
relation to the men of the same tribe; and their opposites
® Dr. Prosper Despine in his ‘‘Psychologie Naturelle’? 1808 (tom. i. p.
243; tom. ii. p. 169), gives many curious cases of the worst criminals, who
apparently have been entirely destitute of conscience,
THE DESCENT OR ORIGIN OF MAN 159
are not regarded as crimes in relation to the men of other
tribes. No tribe could hold together if murder, robbery,
treachery, etc., were common; consequently such crimes
within the limits of the same tribe ‘‘are branded with ever-
lasting infamy;’’™ but excite no such sentiment beyond
these limits. A North American Indian is well pleased
with himself, and is honored 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,” 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,** but rather, from the
courage displayed, as an honorable act; and it is still prac-
ticed by some semi-civilized and savage nations without re-
proach, 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
civilization the robbery of strangers is, indeed, generally
considered as honorable.
Slavery, although in some ways beneficial during ancient
times, 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
31 See an able article in the ‘‘North British Review,’’ 1867, p. 395. See
also Mr. W. Bagehot’s articles on the Importance of Obedience and Coherence
to Primitive Man, in the ‘‘Fortnightly Review,’’ 1867, p. 529, and 1868,
. 457, ete.
Po The fullest account which I have met with is by Dr. Gerland, in his
‘Ueber das Aussterben der Naturvolker,’’ 1868; but I shall have to recur to
the subject of infanticide in a future chapter.
33 See the very interesting discussion on Suicide in Lecky’s ‘‘History of
European Morals,” vol. 1., 1869, p. 223. With respect to savages, Mr. Win-
wood Reade informs me that the negroes of West Africa often commit suicide.
It is well known how common it was among the miserable aborigines of South
America, after the Spanish conquest. For New Zealand, see the voyage of the
“‘Novara,’’ and for the Aleutian Islands, Miller, as quoted by Houzeau, “Tes
Facultés Mentales,’’ ete., tom. ii. p. 136.
#4 See Mr, Bagehot, ‘‘Physics and Polities,’? 1872, p. 72.
160 THE DESCENT OF MAN
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 known that the women and
children of the North American Indians aided in torturing
their enemies. Some savages take a horrid pleasure in
cruelty to animals,* and humanity is an unknown virtue.
Nevertheless, besides the family affections, kindness is com-
mon, 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 sav-
ages toward each other, but not to strangers; common ex-
perience 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 mem-
bers of the same tribe: thus Mungo 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 practiced by savages,
even at a high cost, toward strangers; but to lie to your
enemy has rarely been thought a sin, as the history of mod-
ern diplomacy too plainly shows. As soon as a tribe has a
recognized 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 civilized
countries a good yet timid man may be far more useful to
the community than a brave one, we cannot help instinc-
tively honoring the latter above a coward, however benevo-
lent. Prudence, on the other hand, which does not concern
the welfare of others, though a very useful virtue, has never
35 See, for instance, Mr. Hamilton’s account of the Kaffirs, ‘ Anthropo-
logical Review,’’ 1870, p. xv.
THE DESCENT OR ORIGIN OF MAN 161
been highly esteemed. As no man can practice the virtues
necessary for the welfare of his tribe without self-sacrifice,
self-command, and the power of 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 strengthen his forti-
tude 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 civilized nations. The greatest in-
temperance is no reproach with savages. Utter licentious-
ness and unnatural crimes prevail to an astounding extent.™
As soon, however, as marriage, whether polygamous or
monogamous, becomes common, jealousy will lead to the
inculcation of female virtue; and this, being honored, will
tend to spread to the unmarried females. How slowly it
spreads to the male sex we see at the present day. Chastity
eminently requires self-command; therefore it has been
honored from a very early period in the moral history of
civilized man. As a consequence of this, the senseless
practice of celibacy has been ranked from a remote period
as a virtue.*’ The hatred of indecency, which appears to
us so natural as to be thought innate, and which is so valu-
able an aid to chastity, is a modern virtue, appertaining
exclusively, as Sir G. Staunton remarks,* to civilized life.
This is shown 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 savages,
and were probably so regarded by primeval man, as good or
88 Mr, M‘Lennan has given (‘‘Primitive Marriage,’’ 1865, p. 176) a good
collection of facts on this head.
31 Lecky, ‘‘History of European Morals,’ vol. i, 1869, p. 109,
38 *“Embassy to China,”’ vol. ii. p. 348.
162 THE DESCENT OF MAN
bad, solely as they obviously affect the welfare of the tribe
—not that of the species, nor that of an individual member
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 sav-
ages, as judged by our standard, are, first, the confinement
of sympathy to the same tribe. Secondly, powers of reason-
ing insufficient to recognize the bearing of many virtues,
especially of the self-regarding virtues, on the general wel-
fare of the tribe. Savages, for instance, fail to trace the
multiplied evils consequent on a want of temperance, chas-
tity, ete. And, thirdly, weak power of self-command; for
this power has not been strengthened through long-contin-
ued, perhaps inherited, habit, instruction, and religion.
T have entered into the above details on the immorality
of savages,** because some authors have recently taken a
high view of their moral nature, or have attributed most
of their crimes to mistaken benevolence.” These authors
appear to rest their conclusion on savages possessing those
virtues which are serviceable, or even necessary, 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 phi-
losophers of the derivative’ school of morals that the foun-
dation of morality lay in a form of Selfishness; but more
recently the ‘‘Greatest happiness principle’ has been brought
prominently forward. It 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
88 See on this subject copious evidence in chap. vii. of Sir J. Lubbock,
“Origin of Civilization,”? 1870.
40 For instance, Lecky, ‘“‘History of European Morals,” vol. i. p. 124.
41 This term is used in an able article in the ‘“Westminster Review,’’ Oct.
1869, p. 498, For the ‘Greatest happiness principle,” see J. 8. Mill, ‘‘Utili-
tarianism,”’ p. 17. :
7HE DESCENT OR ORIGIN OF MAN 163
have consulted, with a few exceptions,” 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 endeavors 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 dissatis-
faction which he might subsequently experience if he did
not make the attempt. Should he afterward 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
appropriate to speak of their social instincts as having been
developed 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 vigor 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
42 Mill recognizes (‘‘System of Logic,” vol. ii. p. 422) in the clearest man-
ner, that actions may be performed through habit withcut the anticipation of
pleasure. Mr. H. Sidgwick also, in his Essay on Pleasure and Desire (‘‘The
. Contemporary Review,”’ April, 1872, p. 671), remarks: ‘*‘To sum up, in contra-
vention of the doctrine that our conscious active impulses are always directed
toward the production of agreeable sensations in ourselves, I would maintain
that we find everywhere in consciousness extra-regarding impulse, directed
toward something that is not pleasure; that in many cases the impulse is so far
jncompatible with the self-regarding that the two do not easily coexist in the
same moment of consciousness.’”? A dim feeling that our impulses do not by
any means always arise from any contemporaneous or anticipated pleasure
has, I cannot but think, been one chief cause of the acceptance of the intuitive
theory of morality, and of the rejection of the utilitarian or “Greatest happi-
ess’’ theory. With respect to the latter theory, the standard and the motive
of conduct have no doubt often been confused, but they are really in some
degree blended,
164 THE DESCENT OF MAN
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 un-
happy. We have seen that, even at an early period in the
history of man, the expressed wishes of the 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 important
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 pre-
vented, 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 Honor,
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
recognize the same influence in the burning sense of shame
which most of us have felt, even after the interval of years,
THE DESCENT OR ORIGIN OF MAN 165
when calling to mind some accidental breach of a trifling,
though fixed, rule of etiquette. The judgment of the com-
munity will generally be guided by some rude experience
of what is best in the long run for all the members; but this
judgment will not rarely err from ignorance and weak
powers of reasoning. Hence the strangest customs and
superstitions, in complete opposition to the true welfare
and happiness of mankind, have become all-powerful
throughout the world. We see this in the horror felt by
a Hindu who breaks his caste, and in many other such
cases. It would be difficult to distinguish between the
remorse felt by a Hindu 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; nor 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, while 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 independ-
ently 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; -nor,
again, why similar differences prevail even among highly
civilized 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 gener-
ally and readily distinguish between the higher and lower
8 Good instances are given by Mr. Wallace in ‘‘Scientific Opinion,’’ Sept.
15, 1869; and more fully in his ‘‘Contributions to the Theory of Natural Selee-
tion,”’ 1870, p. 353.
166 THE DESCENT OF MAN
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
rules, though some of them when implying self-sacrifice
hardly deserve to be called lower, relate chiefly to self, and
arise from public opinion, matured by experience and culti-
vation; for they are not practiced by rude tribes.
As man advances in civilization, and small tribes are
united into larger communities, the simplest reason would
tell each individual that he ought to extend his social in-
stincts 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 pre-
vent his sympathies extending to the men of all nations
and races. If, indeed, such men are separated from him
by great differences in appearance or habits, experience
unfortunately shows us how long it is before we look at
them as our fellow-creatures. Sympathy beyond the con-
fines 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 toward their pets. How little the
old Romans knew of it is shown by their abhorrent gladia-
torial 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 honored and practiced by some few men, it spreads
through instruction and example to the young, and event-
ually becomes incorporated in public opinion.
The highest possible stage in moral culture is when we
recognize 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.’’“* Whatever makes any bad
“4 Tennyson, ‘‘Idylls of the King,”’ p. 244.
THE DESCENT OR ORIGIN OF MAN 167
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 thy mind; for the soul is dyed by the thoughts.’’ *°
Our great philosopher, Herbert Spencer, has recently
explained his views on the moral sense. He says,‘ ‘‘I
believe that the experiences of utility, organized and con-
solidated 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 in the
wealthy classes, we can hardly account by accidental coin-
cidence for the tendency occurring in two or three members
of the same family. If bad tendencies are transmitted, it is
probable that good ones are likewise transmitted. ‘That the
state of the body, by affecting the brain, 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 shown by the ‘‘perver-
sion or destruction of the moral sense being often one of the
earliest symptoms of mental derangement;’’ *” and insanity
is notoriously often inherited. Except through the principle
of the transmission of moral tendencies, we cannot under-
45 “The Thoughts of the Emperor M. Aurelius Antoninus,’’ Eng. translat.,
2d edit., 1869, p. 112. Marcus Aurelius was born A.D. 121. .
46 Letter to Mr. Mill in Bain’s ‘‘Mental and Moral Science,’’ 1868,
p. 722.
“| Maudsley, ‘‘Body and Mind,’’ 1870, p. 60.
168 THE DESCENT OF MAN
stand the differences believed to exist in this respect be-
tween 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 in-
herited, it appears probable, at least in such cases as chas-
tity, temperance, humanity to animals, etc., 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 having succeeded best in the struggle for life. My
chief source of doubt with respect to any such inheritance
is that senseless customs, superstitions, and tastes, such as
the horror of a Hindu for unclean food, ought on the same
principle to be transmitted. I have not met with any evi-
dence 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 ac-
quired 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 com-
pelled him to regard their approbation and disapprobation.
Such impulses will have served him ata 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
sufficient knowledge to reject baneful customs and super-
stitions; as he regarded more and more not only the welfare,
but the happiness of his fellow-men; as from habit, follow-
ing on beneficial experience, instruction, and example, his
sympathies became more tender and widely diffused, ex-
tending to men of all races, to the imbecile, maimed, and
other useless members of society, and finally to the lower
‘
THE DESCENT OR ORIGIN OF MAN 169
animals—so would the standard of his morality rise higher
and higher. And it is admitted by moralists of the deriva-
tive school, and by some intuitionists, that the standard
of morality has risen since an early period in the history
of man.* :
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*® has remarked, is all the less surprising, as man has
emerged from a state of barbarism within a comparatively
recent period. After having yielded 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 balked. 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 learned that it will appear to us hereafter
the stronger, when compared with the weakened impression
of the temptation, and we realize 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.
48 A writer in the ‘North British Review”’ (July, 1869, p. 531), well capable
of forming a sound judgment, expresses himself strongly i in favor of this con-
clusion. Mr. Lecky (‘‘Hist. of Morals,’’ vol. i. p. 143) seems to a certain extent
to coincide therein.
49 See his remarkable work on ‘‘Hereditary Genius,’ 1869, p. 349. The
Duke of Argyll (‘Primeval Man,’’ 1869, p. 188) has some good remarks on
the contest in man’s nature between right and wrong.
Descent—Vo.L. I.—8
170 THE DESCENT OF MAN
Summary of the last two OChapters.—There can be no
doubt that the difference between the mind of the lowest
man and that of the highest animal is immense. An anthro-
pomorphous 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 quite beyond
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 God, or admire a grand
natural scene. Some apes, however, would probably de-
clare that they could and did admire the beauty of the
colored skin and fur of their partners .in marriage. They
would admit that, though they could make other apes
understand by cries some of their perceptions 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 acknowledge that disinterested love for all living crea-
tures, the most 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 intui-
tions, the various emotions and faculties, such as love,
memory, attention, curiosity, imitation, reason, etc., of
which man boasts, may be found in an incipient, or even
sometimes in a well-developed condition, in the lower ani-
mals. They are also capable of some inherited improve-
ment, 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-consciousness, etc., were absolutely peculiar to man,
which seems extremely doubtful, it is not improbable that
THE DESCENT OR ORIGIN OF MAN 171
these qualities are merely the incidental results of other
highly advanced intellectual faculties; and these again
mainly the result of the continued use of a perfect lan-
guage. 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 be-
tween man and the lower animals; but I need say nothing
on this head, as I have so lately endeavored to show that
the social instincts—the prime principle of man’s moral con-
stitution®—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 like-
wise’; and this lies at the foundation of morality.
In the next chapter I shall make some few remarks on
the probable steps and means by which the several mental
and moral faculties of man have been gradually evolved.
That such evolution 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.
60 “The Thoughts of Marcus Aurelius,”’ etc., p. 139,
172 THE DESCENT OF MAN
CHAPTER V
ON THE DEVELOPMENT OF THE INTELLECTUAL AND MORAL
FACULTIES DURING PRIMEVAL AND CIVILIZED TIMES
Advancement of the intellectual powers through natural selection—Impor-
tance of imitation—Social and moral faculties—Their development
within the limits of the same tribe—Natural selection as affecting
civilized nations—Evidence that civilized nations were once barbarous
HE subjects to be discussed in this chapter are of the
T highest interest, but are treated by me in an imper-
fect and fragmentary manner. Mr. Wallace, in an
‘admirable paper before referred to,’ argues that man, after
he had partially acquired those intellectual and moral facul-
ties 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. Hven at a remote period he prac-
ticed some division of labor.
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
® “Anthropological Review,” May 1864, p. elviii.
THE DESCENT OR ORIGIN OF yan 175
escape detection and danger. When they migray, there
colder climate, they must become clothed with ~ ther
fur, or have their constitutions altered. If they fail to’.
thus modified, they will cease to exist.
The case, however is widely different, as Mr. Wales.
has 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 pro-
genitors, 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 subsist-
ence, and this depends partly on the physical nature of the
country, but in a much higher degree on the arts which are
there practiced. As a tribe increases and is victorious, it
is often still further increased by the absorption of other
tribes.? The stature and strength of the men of a tribe are
likewise of some importance for its success, and these de-
pend 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;* but their
success was probably still more due to their superiority
in the arts.
2 After a time the members or tribes which are absorbed into another tribe
assume, as Sir Henry Maine remarks (‘‘Ancient Law,’’ 1861, p. 131), that they
are the co-descendants of the same ancestors.
3 Morlot, ‘‘Soc, Vaud. Sc. Nat.,’’ 1860, p. 294,
172 THE DESCENT OF MAN
that we know about savages, or may infer from their
_vns and from old monuments, the history of which is
ite forgotten by the present inhabitants, show that from
the remotest times successful tribes have supplanted other
_ tribes. Relics of extinct or forgotten tribes have. been dis-
covered throughout the civilized regions of the earth, on the
wild plains of America, and on the isolated islands in
the Pacific Ocean. At the present day civilized nations
are everywhere supplanting barbarous nations, excepting
where the climate opposes a deadly barrier; and they suc-
ceed mainly, though not exclusively, through their arts,
which are the products 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 conclusion is sufficient for our purpose.
Undoubtedly it would be interesting to trace the develop-
ment of each separate faculty 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 early
period), the principle of imitation, and reason, and experi-
ence would have increased, and much modified the intel-
lectual 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, shows 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 rea-
soning 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
tw
|
THE DESCENT OR an OF MAN 175
oa
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 preserv-
ing 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 progenitors of man, should
become social, they musf 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 de-
gree of sympathy, fidelity, and courage. Such social quali-
ties, the paramount importance of which to the lower ani-
mals is disputed by no one, were no doubt 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, sympa-
thetic, 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 ad-
4 T have given instances in my ‘‘Variation of Animals under Domestication,”
vol. ii. p. 196.
176 THE, + "SCENT OF MAN
1
vantage which disciplined soldiers have over undisciplined
hordes follows chiefly from the confidence which each man
feels in his comrades. Obedience, as Mr. Bagehot has well
shown, 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 victo-
rious over other 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 so-
cial and moral qualities would tend slowly to advance and
be diffused throughout the world.
But 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 stand-
ard of excellence raised? Itis extremely doubtful whether
the offspring of the more sympathetic and benevolent par-
ents, or of those who were the most faithful to their com-
rades, 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 excel-
lence, 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
5 See a remarkable series of articles on ‘‘Physics and Politics,’ in the
“Fortnightly Review,’’? Nov. 1867; April 1, 1868; July 1, 1869, since sepa-
rately published.
t
f
|
THE DESCENT OR ORIGIN OF MAN 177
too complex to be clearly followed out, we can trace some
of the probable steps. In the first place, as the reasoning
powers and 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
development of the social virtues is afforded by the praise
and the blame of our fellow-men. To the instinct of sym-
pathy, as we have already seen, it is primarily due that we
habitually bestow both praise and blame on others, while
we love the former and dread the latter when applied to our-
selves; 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
appreciate 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 personal 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 shown by the case
of the Australian who grew thin and could not rest from
having delayed to murder some other woman, so as to pro-
Pitiate 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
178 THE DESCENT OF MAN
break his parole,* 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 general good, and would reprobate that which appeared
evil. Todo good unto others—to do unto others as ye would
they should do unto you—is the foundation-stone of moral-
ity. It is, therefore, hardly possible to exaggerate the im-
portance, during rude times, 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 ad-
miration. 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-regard-
ing virtues, such as temperance, chastity, etc., 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 indi-
vidual man and his children over the other men of the same
6 Mr. Wallace gives cases in his ‘‘Contributions to the Theory of Natural
Selection,’’ 1870, p. 354.
THE DESCENT OR ORIGIN OF MAN 179
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 an-
other. A tribe including many members who, from pos-
sessing 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
everywhere 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 civilization. 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,’ “the greatest
part of mankind has never shown a particle of desire that
its civil institutions should be improved.’’ Progress seems
to depend on many concurrent favorable conditions, far toa
complex to be followed out. But it has often been remarked
that a cool climate, from leading to industry and to the vari-
ous arts, has been highly favorable thereto. The Eskimos,
pressed by hard necessity, have succeeded in many ingen-
ious 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 detri-
mental. While observing the barbarous inhabitants of Tierra
1 “Ancient Law,’? 1861, p. 22. For Mr. Bagehot’s remarks, ‘‘Fortnightly
Review,’ April 1, 1868, p. 452.
180 | THE DESCENT OF MAN
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 civilization. Such hab-
its almost necessitate the cultivation of the ground; and the
first steps in cultivation would probably result, as I have
elsewhere shown,® 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 toward civilization is at present much
too difficult to be solved.
Natural Selection as Affecting Civilized 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 civilized
nations may be worth adding. This subject has been ably
discussed by Mr. W. R. Greg,°® and previously by Mr. Wal-
lace and Mr. Galton.’ 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 civilized men, on
the other hand, do our utmost to check the process of elimi-
nation; we build asylums for the imbecile, the maimed, and
the sick; we institute poor-laws; and our medical 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
8 “The Variation of Animals and Plants under Domestication,’’ vol. i,
» BOD,
9 ‘‘Praser’s Magazine,’’ Sept. 1868, p. 353. This article seems to have
struck many persons, and has given rise to two remarkable essays and a re-
joinder in the ‘‘Spectator,’’ Oct. 3d and 17th, 1868. It has also been discussed
in the ‘‘Q. Journal of Science,’’ 1869, p. 152, and by Mr. Lawson Tait in the
“Dublin Q. Journal of Medical Science,’’ Feb. 1869, and by Mr. E. Ray
Lankester in his ‘‘Comparative Longevity,’’? 1870, p. 128. Similar views ap-
peared previously in the ‘‘Australasian,”? July*13, 186%. I have borrowed
ideas from several of these writers. ‘
10 For Mr. Wallace, see ‘‘Anthropolog. Review,’’ us before cited. Mr.
Galton in ‘‘Macmillan’s Magazine,’? Aug. 1865, p. 318; also his great work,
‘Hereditary Genius,’’ 1870.
’
THE DESCENT OR ORIGIN OF MAN 181
formerly have succumbed to small-pox. Thus the weak
members of civilized 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 subsequently rendered, in the manner previously indi-
eated, more tender and more widely diffused. Nor could
we check our sympathy, even at the urging of hard reason,
without deterioration in the noblest part of our nature. The
surgeon may harden himself while 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 help-
less, it could only be for a contingent benefit, with an over-
whelming present evil. We must therefore bear the un-
doubtedly 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 mem-
bers 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.”
" Prof. H. Fick (‘‘Einfluss der Naturwissenschaft auf das Recht,’”? June,
1872) has some good remarks on this head, and on other such points.
182 THE DESCENT OF MAN
Man accumulates property and bequeaths it to his chil-
dren, so that the children of the rich have an advantage
over the poor in the race for success, independently of
bodily or mental superiority. On the other hand, the chil-
dren of parents who are short-lived, and are therefore on
an average deficient in health and vigor, come into. their
property sooner than other children, and will be likely to
marry earlier, and leave a larger number of offspring to
inherit their inferior constitutions. But the inheritance
of property by itself is very far from an evil; for without
the accumulation of capital the arts could not progress; and
it is chiefly through their power that the civilized races have
extended, and are now everywhere extending their range, so
as to take the place of the lower races. Nor does the mod-
erate 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 strug-
gle enough, so that the able in body and mind succeed best.
The presence of a body of well-instructed men, who have
not to labor 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 profli-
gate, 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, while the younger sons, however supe-
rior in these respects, do not so generally marry. Nor can
worthless eldest sons with entailed estates squander their
wealth. But here, as elsewhere, the relations of civilized
life are so complex that some compensatory checks inter-
THE DESCENT OR ORIGIN OF MAN 183
vene. The men who are rich through primogeniture are
able to select generation 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 daugh:
ters of parents who have produced single children are them-
selves, as Mr. Galton’? has shown, 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, unfortu-
nately, this channel is not determined by superiority of any
kind.
Although civilization thus checks in many ways the
action of natural selection, it apparently favors the better
development of the body, by means of good food and the
freedom from occasional hardships. This may be inferred
from civilized men having been found, wherever compared,
to be physically stronger than savages.** They appear also
to have equal powers of endurance, as has been proved in
many adventurous expeditions. 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. **
We will now look to the intellectual faculties. If in each
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 oc-
2 “‘Hereditary Genius,’? 1870, pp. 132-140.
18 Quatrefages, ‘‘Revue des Cours Scientifiques,’’ 1867-68, p. 659.
14 See the fifth and sixth columns, compiled from good authorities, in the
table given in Mr. E. R. Lankester’s ‘‘Comparative Longevity,’’ 1870, p. 115.
184 THE DESCENT OF MAN
cupations, owing to the great division of labor, a very small
one. Hence in civilized 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 multiplication of the reckless and improvi-
dent; 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,*®
“T regret I am unable to solve the simple question whether,
and how far, men and women who are prodigies of genius
are infertile. I have, however, shown that men of eminence
are by no means so.’’ Great lawgivers, the founders of
beneficent religions, great 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 preservation of
strongly marked and rare anomalies, that leads to the ad-
vancement of a species.’* So it will be with the intellec-
tual faculties, since the somewhat abler men in each grade
of society succeed rather better than the less able, and con-
sequently increase in number, if not otherwise prevented.
When in any nation the standard of intellect and the num-
ber of intellectual men have increased, we may expect, from
the law of the deviation from an average, that prodigies of
genius will, as shown 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
civilized nations. Malefactors are executed, or imprisoned
16 “‘Hereditary Genius,’’ 1870, p. 330.
16 “Origin of Species’’ (fifth edition, 1869), p. 104.
THE DESCENT OR ORIGIN OF MAN 185
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 civilization’’—emigrate to newly settled countries,
where they prove useful pioneers. Intemperance is so highly
destructive, that the expectation of life of the intemperate,
at the age of thirty for instance, is only 18.8 years; while
for the rural laborers of England at the same age it is 40.59
years.’* Profligate women bear few children, and profligate
men rarely marry; both suffer from disease. In the breed-
ing of domestic animals, the elimination of those individuals,
though few in number, which are in any marked manner in-
ferior, is by no means an unimportant element toward suc-
cess. This especially holds good with injurious characters
which tend to 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 sav-
age state, from which we are not removed by very many
generations. This, view seems indeed recognized in the
common expression that such men are the black sheep
of the family.
With civilized nations, as far as an advanced standard
of morality and an increased number of fairly good men
are concerned, natural selection apparently effects but little;
though the fundamental social instincts were originally thus
gained. But I have already said enough, while treating of
the lower races, on the causes which lead to the advance
of morality, namely, the approbation of our fellow-men—
the strengthening of our sympathies by habit—example
" ‘Hereditary Genius,’ 1870, p. 347.
18 E, Ray Lankester, ‘‘Comparative Longevity,’? 1870, p. 115. The table
of the intemperate is from Neison’s ‘‘Vital Statistics.’? In regard to profligacy,
see Dr. Farr, ‘‘Influence of Marriage on Mortality,” ‘‘Nat. Assoc. for the
Promotion of Social Science,’’ 1858.
186 THE DESCENT OF MAN
and imitation—reason—experience, and even self-interest
—instruction during youth, and religious feelings.
A most important obstacle in civilized countries to an
increase in the number of men of a superior class has been
strongly insisted on by Mr. Greg and Mr. Galton,” namely,
the fact that the very poor and reckless, who are often de-
graded by vice, almost invariably marry early, while the
careful and frugal, who are generally otherwise virtuous,
marry late in life, so that they may be able to support them-
selves and their children in comfort. Those who marry early
produce within a given period not only a greater number of
generations, but, as shown by Dr. Duncan,” they produce
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, un-
aspiring Irishman multiplies like rabbits: the frugal, fore-
seeing, self-respecting, ambitious Scot, stern in his morality,
spiritual in his faith, sagacious and disciplined in his intel-
ligence, 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 popu-
lation 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 ex-
istence,’ it would be the inferior and less favored race that
19 “‘Frager’s Magazine,’? Sept. 1868, p. 353. ‘‘Macmillan’s Magazine,”’
Aug. 1865, p. 318. The Rev. F. W. Farrar (“‘Fraser’s Mag.,’? Aug. 1830,
p. 264) lakes a different view.
20 ‘On the Laws of the Fertility of Women,”’ in ‘‘Transact. Royal Soc.,”’
Edinburgh, vol. xxiv. p. 287; now published separately under the title of
“Fecundity, Fertility, and Sterility,’? 1871. See, also, Mr. Galton, “Hereditary
Genius,” pp. 352-357, for observations to the above effect.
THE DESCENT OR ORIGIN OF MAN 187
44d prevailed—and prevailed by virtue not of its good
qualities, but of its faults.’
There are, however, some checks to this downward ten-
dency. 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,” that at all ages the death-rate is higher
in towns than in rural districts, ‘‘and during the first five
years of life the town death-rate is almost exactly double
that of the rural districts.’’ As these returns 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,’’ 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 1,000 unmarried men, between the ages of twenty
and thirty, 11.8 annually died, while of the married only
6.5 died.” A similar law was proved to hold good, during
21 *‘Tenth Annual Report of Births, Deaths, etc., in Scotland,’’ 1867,
. XXX.
ane These quotations are taken from our highest authority on such questions,
namely Dr, Fair, in his paper ‘‘On the Influence of Marriage on the Mortality
of the French People,” read before the Nat. Assoc. for the Promotion of Social
Science, 1858.i:
% Dr, Farr, ib. The quotations given below are extracted from the same
ee paper.
188 THE DESCENT OF MAN
the years 1863 and 1864, with the entire population above the
age of twenty in Scotland; for instance, out of every 1,000
unmarried men, between the ages of twenty and thirty,
14.97 annually died, while of the married only 7.24 died,
that is less than half.* 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 dis-
tant 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 com-
monly marry; and it must likewise be admitted that men
with a weak constitution, 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 ‘outh, did not marry,
and yet have survived to old age, though remaining weak,
and therefore 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 mortality; 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
*4 T have taken the mean of the quinquennial means, given in ‘‘The Tenth
Annual Report of Births, Deaths, etc., in Scotland, ”? 186%, The Srotation from
Dr. Stark is copied from an article in the “Daily News,” Octob ir 117, 1868,
which Dr. Farr considers very carefully written.
THE DESCENT OR ORIGIN OF MAN 189
imperfect types, and to the skilful selection of the finest
individuals out of each successive generation’’; the selection
relating only to the married state, and acting on all cor-
poreal, intellectual, and moral qualities.» We may, there-
fore, 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 last two paragraphs,
and perhaps others as yet unknown, do not prevent the
reckless, the vicious, and otherwise inferior members of
society from increasing 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 very difficult to
say why one civilized 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 en-
dowed with high intellectual and moral faculties, as well
as on their standard of excellence. Corporeal structure ap-
pears to have little inflzence, except so far as vigor of body
leads to vigor of mind.
It has been urged by several writers, that as high intel-
lectual powers are advantageous to a nation, the old Greeks,
who stood some grades higher in intellect than any race that
has ever existed,” 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 assumption, so often made with respect to corporeal
structures, that there is some innate tendency toward con-
% Dr, Duncan remarks (‘‘Fecundity, Fertility,’? etc., 1871, page 334) on
this subject:
‘‘At every age the healthy and beautiful go over from the unmarried side
to the married, leaving the unmarried columns crowded with the sickly and
unfortunate. ’’
96 See the ingenious and original argument on this subject by Mr. Galton,
“Hereditary Genius,” pp. 340-342.
190 THE DESCENT OF MAN
tinued development in mind and body. But development
of all kinds depends on many concurrent favorable circum-
stances. Natural selection acts only tentatively. Individ-
uals and races may have acquired certain 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.’’*” The
western nations of Hurope, who now so immeasurably sur-
pass their former savage progenitors, and stand at the
summit of civilization, owe little or none of their superior-
ity 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 perplexing 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 de-
manded celibacy;” 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
centuries at the rate of a thousand a year. The evil which
the Catholic Church has thus effected is incalculable, though
21 Mr, Greg, ‘‘Fraser’s Magazine,’’ September, 1868, p. 357.
98 ‘Hereditary Genius,’? 1870, pp. 357-359. The Rev. F. W. Farrar
(‘‘Fraser’s Mag.,”? Aug. 1870, p. 257) advances arguments on the other side.
Sir ©. Lyell had already (‘‘Principles of Geology,”’ vol. ii., 1868, p. 489).in a
striking passage called attention to the evil influence of the Holy Inquisition
in having, through selection, lowered the general standard of intelligence in
Europe.
THE DESCENT OR ORIGIN OF MAN 191
no doubt counterbalanced to a certain, perhaps to a large,
extent in other ways; nevertheless, Europe has progressed
at an unparalleled rate.
The remarkable success of the English as colonists, com-
pared to other European nations, has been ascribed to their
‘daring and persistent energy’’; a result which is well illus-
trated by comparing the progress of the Canadians of En. |
glish 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 energetic, restless, and
courageous men from all parts of Europe have emigrated
during the last ten or twelve generations to that great coun-
try, and have there succeeded best.” Looking to the distant
future, I do not think that the Rev. Mr. Zincke takes an ex-
aggerated view when he says:” ‘‘ All other series of events—
as that which resulted in the culture of mind in Greece, and
that which resulted in the empire of Rome—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 civilization, 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 favored 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 civilized nations to abject poverty, celibacy, and to the
late marriages of the prudent. But as man suffers from
° Mr. ‘Galton, ‘‘Macmillan’s Mag.,”? Aug. 1865, p. 325. See, also,
“Nature,’’ “‘On Darwinism and National Life,’? Dec. 1869, p. 184.
30 “Last Winter in the United States,’’ 1868, p. 29.
192 THE DESCENT OF MAN
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 subjected during
primeval ‘times to natural selection, assuredly he would
never have attained to his present rank. Since we see ia
many parts of the world enormous areas of the most fertile
land capable of supporting numerous happy homes, but peo-
pled only by a few wandering savages, it might be argued
that the struggle for existence had not been sufficiently
severe to force man upward to his highest standard. Judg-
ing from all that we know of man and the lower animals,
there has always been sufficient variability in their intel-
lectual and moral faculties for a steady advance through
natural selection. No doubt such advance demands many
favorable concurrent circumstances; but it may well be
doubted whether the most favorable 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 South America,
that a people which may be called civilized, such as the
Spanish settlers, is liable to become indolent and to retro-
grade, when the conditions of life are very easy. With
highly civilized nations continued 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
while 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 en-
forced 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 appreciation is founded on our sym-
i.
i
,
(
THE DESCENT OR ORIGIN Or MAN 193
pathy, which it can hardly be doubted was originally
developed through natural selection as one of the most
important elements of the social instincts.”
On the Evidence that all Civilized Nations were once
Barbarous.—The present subject has been treated in so full
and admirable a manner by Sir J. Lubbock,” Mr. Tylor,
Mr. M‘Lennan, and others that I need here give only the
briefest summary of their results. The arguments recently
advanced by the Duke of Argyll,* and formerly by Arch.
bishop Whately, in favor of the belief that man came into
the world as a civilized being, and that all savages have
since undergone degradation, seem to me weak in compari-
son with those advanced on the other side. Many nations,
no doubt, have fallen away in civilization, 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 in-
hospitable country, and they may have become in conse-
quence somewhat more degraded; but it would be difficult
to prove that they have fallen much below the Botocudos,
who inhabit the finest parts of Brazil.
The evidence that all civilized nations are the descend-
ants of barbarians, consists, on the one side, of clear traces of
their former low condition in still-existing customs, beliefs,
language, etc.; and, on the other side, of proofs that savages
are independently able to raise themselves a few steps in
the scale of civilization, 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 shows by reference
to the words still used in some places, originated in count-
ing the fingers, first of one hand and then of the other, and
21 IT am much indebted to Mr. John Morley for some good criticisms on this
subject: see, also, Broca, ‘Les Sélections,”’ “Revue d’Anthropologie,”’ 1872.
# “On the Origin of Civilization,” ‘‘Proc. of the Ethnological Society,”
November 26, 1867.
33 **Primeval Man,’’ 1869.
Descent—Votu. I.—9
194 “THE DESCENT OF MAN
lastly of the toes. We have traces of this in our own deci-
mal 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., etc., 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.’’ *
According toa 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®® and not admit that almost
all civilized 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 monog-
amous? The primitive idea of justice, as shown by the
law of battle and other customs of which vestiges still re-
main, 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 righteousness—was unknown during primeval
times.
Turning to the other kind of evidence: Sir J. Lubbock
has shown that.some savages have recently improved 4 little
in some of their simpler arts. From the extremely curious
account which he gives of the weapons, tools, and arts in
use among savages in various parts of the world, it cannot
be doubted that these have nearly all been independent dis-
34 ‘Royal Institution of Great Britain,’? March 15, 1867. Also, ‘Researches
into the Early History of Mankind,’’ 1865. :
85 ‘Primitive Marriage,’? 1865. See, likewise, an excellent article, evidently
by the same author, in the ‘“‘North British Review,’ July, 1869. Also, Mr.
L. H. Morgan, ‘‘A Conjectural Solution of the Origin of the Class System of
Relationship,’? in ‘‘Proc. American Acad. of Sciences,’’ vol. vii., February,
1868. Prof. Schaaffhausen (‘‘Anthropolog. Review,’’ October, 1869, p. 373)
remarks on ‘“‘the vestiges of human sacrifices found both in. Homer and the
Old Testament.”’
THE DESCENT OR ORIGIN OF MAN 195
coveries, excepting perhaps the art of making fire. The
Australian boomerang is a good instance of one such inde-
pendent 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 influ-
ence of most missionaries, a wandering crew from some
semi-civilized 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. Look-
ing to a very remote period in the history of the world, we
find, to use Sir J. Lubbock’s well-known terms, a paleolithie
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 inhabitants 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 civilized world, were once in a barbarous condition.
To believe that man was aboriginally civilized 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 has 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.
% Sir J. Lubbock, ‘‘Prehistoric Times,’? 2d edit., 1869, chap. xv. and xvi.
st passim. See, also, the excellent ninth chapter in Tylor’s ‘Early History of
Mankind,’’ 2d edit., 1870.
31 Dr, F. Miller has made some good remarks to this effect in the ‘‘Reise
der Novara: Anthropolog. Theil,”’ Abtheil. iii., 1868, s. 127,
196 THE DESCENT OF MAN
CHAPTER VI
ON THE AFFINITIES AND GENEALOGY OF MAN
Position of man in the animal series—The natural system genealogical—
Adaptive characters of slight value—Various small points of resem-
blance between man and the Quadrumana—Rank of man in the nat-
ural system—Birthplace and antiquity of man—Absence of fossil con-
necting-links—Lower stages in the genealogy of man, as inferred,
first, from his affinities, and, secondly, from his structure—Harly
androgynous condition of the Vertebrata—Conclusion
T ‘VEN if it be granted that the difference between man
4 and his nearest allies is as great in corporeal structure
4— as some naturalists maintain, and although we must
grant that the difference 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, notwithstanding that connecting-links
have not hitherto been discovered.
Man is liable to numerous slight and diversified varia-
tions, which are induced by the same general causes, are
governed and transmitted in accordance with the same gen-
eral laws, as in the lower animals. Man has multiplied so
rapidly that he has necessarily been exposed to struggle for
existence, and consequently 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 embryological development.
He retains many rudimentary and useless structures, which
no doubt were once serviceable. Characters occasionally
make their reappearance in him, which we have reason to
THE DESCENT OR ORIGIN OF MAN 197
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 appearances, 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 déeply impressed with the
mental and spiritual powers of man, have divided the whole
organic world into three kingdoms—the Human, the Animal,
and the Vegetable—thus giving to man a separate kingdom.’
Spiritual powers cannot be compared or classed by the natu-
ralist; but he may endeavor to show, 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, while young, attaches
itself by its proboscis to a plant; sucks the sap, but never
moves again; is fertilized 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 shown, a large volume; I may, however, briefly
specify a few points. Ants certainly communicate informa-
tion to each other, and several unite for the same work, or
for games of play. They recognize 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
1 Isidore Geoffroy St.-Hilaire gives a detailed account of the position assigned
to man by various naturalists in their classifications: ‘“‘Hist. Nat. Gén.,’’ tom.
ii, 1859, pp. 170-189.
198 THE DESCENT OF MAN
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 afterward 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 according to a
preconcerted plan. They capture slaves. They move the
egos of their aphides, as well as their own eggs and co-
coons, into warm parts of the nest, in order that they may
be quickly hatched; and endless similar facts could be
given.” On the whole, the difference in mental power
between an ant and a coccus is immense; yet no one has
ever dreamed of placing these insects in distinct classes,
much less in distinct kingdoms. No 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.
Prof. 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 de-
velopment of the mental faculties, is almost sure to prove
2 Some of the most interesting facts ever published on the habits of ants
are given by Mr. Belt, in his ‘‘Naturalist in Nicaragua,’’ 1874. See, also, Mr.
Moggridge’s admirable work, ‘‘Harvesting Ants,’’ etc., 1873; also, ‘‘L’Instinct
chez les Insectes,’? by M. George Pouchet, ‘‘Revue des Deux Mondes,’’ Feb-
Tuary, 1870, p. 682.
THE DESCENT OR ORIGIN OF MAN 199
unsatisfactory. This principle has indeed been tried with
hymenopterous insects; but when thus classed by their
habits or instincts, the arrangement proved thoroughly arti-
ficial.* Classifications may, of course, be based on any char-
-acter whatever, as on size, color, 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 arrange-
ment—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 together 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 ob-
serving the degrees of resemblance between the beings which
are to be classed. For this object numerous points of re-
semblance 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 recog-
nized as having sprung from a common source, notwithstand-
ing that they differed greatly in some few words or points of
construction. But with organic beings the points of resem-
blance must not consist of adaptations to similar habits of
life: two animals may, for instance, have had their whole
frames modified for living in the water, and yet they will
not be brought any nearer to each other in the natural
system. Hence we can see how it is that resemblances in
several unimportant structures, in useless and rudimentary
organs, or not now functionally active, or in an embryologi-
cal condition, are by far the most serviceable for classifica-
tion; for they can hardly be due to adaptations within a
8 Westwood, ‘‘Modern Class of Insects,’’ vol. ii., 1840, p. 87.
200 THE DESCENT OF MAN
late period; and thus they reveal the old lines of descent
or of true affinity.
We can further see why a great 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 ex-
citing conditions) 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 continued 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 development 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
consideration 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, etc. Recently many of our
best naturalists have recurred to the view first propounded
by Linnzus, 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 ad-
mitted; for, in the first place, we must bear in mind the
comparative insignificance for classification of the great de-
velopment 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) appar-
ently follow from their differently developed brains. In the
second place, we must remember that nearly all the other
THE DESCENT OR ORIGIN OF MAN 201
and more important differences between man and the Quad-
rumana are manifestly adaptive in their nature, and relate
chiefly to the erect position of man; such as the structure
of his hand, foot, and pelvis, 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 Car-
nivora, 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,‘ seals are ranked as a mere family in the
Order of the Carnivora. If man had not been his own clas-
sifier, 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 paints of struc-
ture in which man agrees with the other Primates. Our
great anatomist and philosopher, Prof. Huxley, has fully
discussed this subject,’ and concludes that man in all parts
of his organization differs less from the higher apes than
these do from the lower members of the same group. Conse-
quently there ‘‘is no justification for placing man in a distinct
order.”
In an early part of this work I brought forward various
facts, showing how closely man agrees in constitution with
the higher mammals; and this agreement must depend on
our close similarity in minute structure and chemical com-
position. I gave, as instances, our liability to the same dis-
eases, 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 sys-
4 “Proc. Zoolog. Soc.,’? 1863, p. 4.
5 “*Ryidence as to Man’s Place in Nature,”’ 1863, p. 70 et passim.
202 THE DESCENT OF MAN
tematic works, and as, when numerous, they clearly reveal
our relationship, I will specify a few such points. The rela-
tive 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, al-
most the same, as in the weeping of certain kinds of mon-
keys and in the laughing noise made by others, during
which the corners of the mouth are drawn backward, 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 nasiea is carried to a ridiculous
extreme.
The faces of many monkeys are ornamented with beards,
whiskers, or mustaches. The hair on the head grows to a
great length in some species of Semnopithecus;° and in the
Bonnet monkey (Macacus radiatus) it radiates from a point
on the crown, with a parting down the middle. It is com-
monly said that the forehead gives to man his noble and
intellectual appearance; but the thick hair on the head of
the Bonnet monkey terminates downward 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 eye-
brows are not present in any monkey. In the species just
named the degree of nakedness of the forehead differs in
different individuals; and Hschricht states’ 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 con-
6 Isid. Geoffroy, ‘‘Hist. Nat. Gén.,”? tom. ii., 1859, p. 217.
1 ‘Ueber die Richtung der Haare,”’ etc. Miiller’s “‘Archiv far Anat. und
Phys.,”? 1837, s. 51.
THE DESCENT OR ORIGIN OF MAN 203
verge 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 of Hylobates, and even to some few American
monkeys. But in Hylobates agilis the hair on the forearm
is directly downward or toward the wrist in the ordinary
manner; and in H. lar it is nearly erect, with only a very
slight forward 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 trans-
verse hairs on. the forelegs of a dog may serve for this end
when he is coiled up asleep. Mr. Wallace, who has care-
fully studied the habits of the orang, remarks that the con-
vergence of the hair toward 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.’’*® If the above explana-
tion is correct, as seems probable, the direction 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 prin-
ciple of adaptation in regard to the direction of the hair in
man orhis early progenitors; for it is impossible to study
the figures given by Eschricht of the arrangement of the
hair4yn the human foetus (this being the same as in the adult)
and not agree with this excellent observer that other and
more complex causes have intervened. The points of con-
vergencd seem to stand in some relation to those points in
the emlpryo which are last closed in during development.
There opear also to exist some relation between the ar-
id
i
® Quoted by Reade, ‘The African Sketch Book,” vol. i., 1873, p. 152.
204 THE DESCENT \OF MAN
rangement of the hair on the limbs and the course of the
medullary arteries.* ,
It must not be supposed that jthe resemblances between
man and certain apes in the above;and many other points—
such as in having a naked fore head, long tresses on the
head, etc.—are all necessarily the ‘result of unbroken inheri-
tance from a common progenitor, or of subsequent rever-
sion. Many of these resemblancies are more probably due
to analogous variation, which follows, as I have elsewhere
attempted to show," from co-descended organisms having
a similar constitution, and having been acted on by like
causes inducing similar modificatiens. With respect to the
similar direction of the hair on the forearms of man and’
certain monkeys, as this character is common to almost all
the anthropomorphous apes, it may probably be attributed
to inheritance; but this is not certain, as aa very distinet
American monkeys are thus characterized. *
Although, as we have now seen, man has no just right
to form a separate Order for his own reception, he may per-
haps claim a distinct Sub-order or Family. Prof. Huxley,
in his last work,'' divides the Primates into three Sub-
orders; namely, the Anthropidsz with man alone, the Simi-
ad, including monkeys of all kinds, and the Wemuride
with the diversified genera of lemurs. As far as Bileence
in certain important points of structure are concerned, man
may no doubt rightly claim the rank of a Sub- oder; and
this rank is too low, if we look chiefly to his mental facul-
ties. 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-faigsily.
AP
1
® On the hair in Hylobates, see ‘“‘Nat. History of Mammals,’* « by CL
Martin, 1841, p. 415. Also, Isid. Geoffroy on the American mor core and
other kinds, “ist, Nat. Gén.,”’ vol. ii., 1859, PP. 216, 248. EschriShi, ibid.,
8. 46, 55, ’el. Owen, “Anat. of Vertebrates,’ vol. iii, p. 619. Wallace,
“Contributions to the Theory of Natural Selection,” 1870, p. 344.
10 “Origin of Species,’’ 5th edit., 1869, p. 194. “The Variation \ Fa
mals and Plants under Domestication,”’ vol, ii., 1868, p. 348. und An
11 ‘*An Introduction to the Classification of Animals,’’ 1869, p. 99. ;
THE DESCENT OR ORIGIN OF MAN 205
Tf we imagine three lines of descent proceeding from a com-
mon stock, it is quite conceivable that two of them might
after the lapse of ages be so slightly changed as still to
remain as species of the -same genus, while 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 differences in some
few points—that is, to the amount of modification under-
gone; 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 atten-
tion 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 Simiade.
This family is divided by almost all naturalists into the
Catarrhine group, or Old World monkeys, all of which are
characterized (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 characterized by differently constructed nostrils,
and by having six premolars in each jaw. Some other
small differences might be mentioned. Now man unques-
tionably belongs in his dentition, in the structure of his
nostrils, and some other respects, to the Catarrhine or Old
“World division; nor does he resemble the Platyrhines more
elosely than the Catarrhines in any characters, excepting
in a few of not much importance and apparently of an
adaptive nature. I+ is therefore against all probability that
some New World species should have formerly varied and
206 THE DESCENT OF MAN
produced a manlike creature, with all the distinctivé char-
acters proper to the Old World division; losing at the same
time all its own distinctive characters. There can, conse-
quently, hardly be a doubt that man is an offshoot from the
Old World Simian stem; and that, under a genealogical
point of view, he must be classed with the Catarrhine
division.”
The anthropomorphous apes, namely, the gorilla, chim-
panzee, orang, and hylobates, are by most naturalists sepa-
rated from the other Old World monkeys, as a distinct sub-
group. JI 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,* ‘‘is one of the most peculiar and
aberrant forms to be found in the Order.’’ The remaining
non-anthropomorphous Old World monkeys are again di-
vided by some naturalists into two or three smaller sub-
groups; the genus Semnopithecus, with its peculiar saccu-
lated 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 those characters which he possesses in common with
the whole Catarrhine 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
12 This is nearly the same classification as that provisionally adopted by
Mr. St. George Mivart (‘‘Transact. Philosoph. Soc.,’’ 186%, p. 300), who, after
separating the Lemuride, divides the remainder of the Primates into the
Hominid, the Simiade which answer to the Catarrhines, the Cebide, and
the Hapalide—these two latter groups answering to the Platyrhimes. Mr.
Mivart still abides by the same view; see ‘‘Nature,’’ 1871, p. 481.
18 “Transact. Zoolog. Soc.,’? vol. vii 1867, p. 214.
THE DESCENT OR ORIGIN OF MAN 207
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 conse-
quence of the great development of his brain and his erect
position; nevertheless, we should béar in mind that he ‘‘is
but one of several exceptional forms of Primates.’’
Every naturalist who believes in the principle of evolu-
tion will grant that the two main divisions of the Simiade,
namely, the Catarrhine and Platyrhine monkeys, with their
sub-groups, have all proceeded from some one extremely
ancient progenitor. The early descendants of this progeni-
tor, 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 Catarrhine and Platyrhine
divisions. Hence the members of this supposed ancient
group would not have been so uniform in their dentition,
‘or in the structure of their nostrils, as are the existing Catar-
rhine monkeys in one way and the Platyrhines in another
way, but would have resembled in this respect the allied
Lemuride, which differ greatly from each other in the form
of their muzzles,** and to an extraordinary degree in their
dentition.
The Catarrhine and Platyrhine monkeys agree in a mul-
titude of characters, as is shown by their unquestionably
belonging to one and the same Order. The many characters
which they possess in common can hardly have been inde-
pendently acquired by so many distinct species; so that
these characters must have been inherited. But a natural-
ist would undoubtedly have ranked as an ape or a monkey
4 Mr, St. George Mivart, ‘“Transact. Phil. Soc.,’’ 1867, p. 410.
18 Messrs. Murie and Mivart on the Lemuroidea, ‘‘Transact. Zoolog. Soc., ’?
vol, vii., 1869, p. 5.
208 THE DESCENT OF MAN
an ancient form which possessed many characters common
to the Catarrhine and Platyrhine monkeys, other characters
in an intermediate condition, and some few, perhaps, distinct
from those now found in either group. And as man from a
genealogical point of view belongs to the Catarrhine or Old
World stock, we must conclude, however much the conclu-
sion may revolt our pride, that our early progenitors would
have been properly thus designated.’* But we must not fall
into the error of supposing that the early progenitor of the
whole Simian stock, including man, was identical with, or
even closely resembled, any existing ape or monkey.
On the Birthplace and Antiquity of -Man.—We are natu-
rally led to inquire, where was the birthplace of man at that
stage of descent when our progenitors diverged from the
Catarrhine stock? The fact that they belonged to this stock
clearly shows 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 inhabited by extinct apes closely
allied to the gorilla and chimpanzee; and as these two spe-
cies are now man’s nearest allies, it is somewhat more prob-
able that our early progenitors lived on the African conti-
nent than elsewhere. But it is useless to speculate on this
subject; for two or three anthropomorphous apes, one the
Dryopithecus” of Lartet, nearly as large as a man, 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.
18 Hackel has come to this same conclusion. See ‘‘Ueber die Entstehung
ges Menschengeschlechts,”’? in Virchow’s ‘‘Sammlung. gemein. wissen. Vor-
trage,’? 1868, s, 61. Also his ‘‘Nattirliche Schépfungsgeschichte,’’ 1868, in
which he gives in detail his views on the genealogy of man.
1 Dr, C. Forsyth Major, ‘‘Sur les Singes Fossiles trouvés en Italie’; “Soc
Ttal. des Sc. Nat.,”? tom. xv., 1872.
YHE DESCENT OR ORIGIN OF MAN 209
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 favorable 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 Catarrhine stock; but it may have oc-
curred 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 shown 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 favorable circumstances; we know, however,
that some have retained the same form during an enormous
lapse of time. From what we see going on under domesti-
‘cation, we learn that some of the co-descendants of the same
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 ex-
tinct 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 Lemu-
ridsee—between the elephant, and in a more striking manner
between the Ornithorhynchus or Kchidna, 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 civilized
races of man will almost certainly exterminate, and replace,
210 THE DESCENT OF MAN
the savage races throughout the world. At the same time
the anthropomorphous apes, as Professor Schaaffhausen has
remarked,** will no doubt be exterminated. The break be-
tween man and his nearest allies will then be wider, for
it will intervene between man in a more civilized 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.
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. Lyell’s discus-
sion,’® where he shows that in all the vertebrate classes the
discovery of fossil remains has been a very slow and fortui.
tous 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.
Lower Stages in the Genealogy of Man.—We have seen
that man appears to have diverged from the Catarrhine or
Old World division of the Simiade, after these had diverged
from the New World division. We will now endeavor to
follow the remote traces of his genealogy, trusting princi
pally 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 Lemurids stand below and near to the Simiada, and
constitute a very distinct family of the Primates, or, accord-
ing to Hackel and others, a distinct Order.” This group is
diversified and broken to an extraordinary degree, and in-
cludes 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
18 “* Anthropological Review,” April, 1867, p. 236.
19 **Blements of Geology,’’ 1865, pp. 583-586. ‘‘Antiquity of Man,”’ 1863,
p. 145.
THE DESCENT OR ORIGIN OF MAN 211
as they would have been on well-stocked continents. This
group likewise presents many gradations, leading, as Huxley
remarks,” ‘‘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 intelli-
gent of the placental mammalia.’’ From these various con-
siderations it is probable that the Simiade were originally
developed from the progenitors of the existing Lemuride;
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 geo-
logical period, and their range was formerly much more
extensive than at present. Hence the Placentata are gen-
erally supposed to have been derived from the Implacentata
or Marsupials; not, however, from forms closely resembling
the existing Marsupials, but from their early progenitors.
The Monotremata are plainly allied to the Marsupials, form- °
ing a third and still lower 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 favorable concurrence of circumstances. The
Monotremata are eminently interesting, as leading in sev-
eral important points of structure toward 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.
Hickel’s works." I will content myself with a few gen-
% ‘*Man’s Place in Nature,”’ p. 106. : i.
9 Blaborate tables are given in his ‘‘Generelle Morphologie” (B, ii, s. cliii,
912 THE DESCENT OF MAN
eral remarks. Every evolutionist will admit that the five
great vertebrate classes, namely, mammals, birds, reptiles,
amphibians, and fishes, are descended from some one proto-
type; for they have much in common, especially during
their embryonic state. As the class of fishes is the most
lowly organized, 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, etc., could all have sprung
from the same parents, will appear monstrous to those who
have not attended to the recent progress of natural his-
tory. 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 toward reptiles:
and Prof. Huxley has discovered, and is confirmed by Mr.
Cope and others, that the Dinosaurians are in many impor-
tant 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, aceording to Prof. Owen,” 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
the Ganoid fishes. These latter fishes swarmed during the
and s. 425); and with more especial reference to man in his ‘‘Natiirliche
Schdpfungsgeschichte,’? 1868. Prof. Huxley, in reviewing this latter work
(‘The Academy,’’ 1869, p, 42), says that he considers the phylum or lines of
descent of the Vertebrata to be admirably discussed by Hackel, although he
differs on some points. He expresses, also, his high estimate of the general
tenor and spirit of the whole work.
32 **Paleontology,”’ 1860, p. 199,
THE DESCENT OR ORIGIN OF MAN 213
earlier geological periods, and were constructed on what is
called a generalized type, that is, they presented diversified
affinities with other groups of organisms. The Lepidosiren
is also so closely allied to amphibians and fishes, that natu- |
ralists 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 harbors
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 dif-
ferent from all other fishes, that Hickel 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, etc.;
so that it was classed by the older naturalists among the
worms. Many years ago Prof. Goodsir perceived that the
lancelet presented some affinities with the Ascidians, which
are invertebrate, hermaphrodite, marine creatures perma-
nently attached to a support. They hardly appear like ani-
mals, and consist of a simple, tough, leathery sack, with
two small projecting orifices. They belong to the Mollus-
coida of Huxley—a lower division of the great kingdom
of the Mollusca; but they have recently been placed by
some naturalists among the Vermes or worms. Their larvae
somewhat resemble tadpoles in shape,” and have the power
of swimming freely about. M. Kovalevsky™ has lately
observed that the larve of Ascidians are related to the
Vertebrata in their manner of development, in the relative
23 At the Falkland Islands I had the satisfaction of seeing, in April, 1833,
and therefore some years before any other naturalist, the locomotive larve of
a compound Ascidian, closely allied to Synoicum, but apparently generically
distinct from it, The tail was about five times as long as the oblong head,
and terminated in a very fine filament. It was, as sketched by me, under
@ simple microscope, plainly divided by -transverse opaque partitions, which
J presume represent the great cells figured by Kovalevsky, At an early stage
of development the tail was closely coiled round the head of the larva.
2% “Miégmoires de l’Acad. des Sciences de St. Pétersbourg,”’ tom. x., No,
15, 1866.
214 THE DESCENT OF MAN
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 confirmed by Prof. Kupffer. M. Kov-
alevsky 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 clew to the source whence the Vertebrata were
derived.** We should then be justified in believing that
at an extremely remote period a group of animals existed,
resembling in many respects the larve of our present As-
cidians, 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 endeavored rudely to trace the gene-
alogy of the Vertebrata by the aid of their mutual affinities.
We will now look to man as he exists; and we shall, [
think, be able partially to restore the structure of our early
progenitors, during successive periods, but not in due order
of time. This can be 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 have been given
in the previous chapters.
The early progenitors of man must have been once cov-
ered with hair, both sexes having beards; their ears were
2% But Iam bound to add that some competent judges dispute this con-
_elusion; for instance, M. Giard, in a series of papers in the ‘‘Archives de.
Zoologie Expérimentale,’’ for 1872. Nevertheless, this naturalist remarks, p.
981, ‘‘L’organisation de la larve ascidienne en dehors de toute hypothése et
de toute théorie, nous montre comment la nature peut produire la disposition
fondamentale du type vertébré (l’existence d’une corde dorsale) chez un in>
vertébré par la seule condition vitale de l’adaptation, et cette simple possibilité
du passage supprime l’abime- entre les deux sous-régnes, encore bien qu’on
ignore par ob le passage s’est fait en réalité.””
THE DESCENT OR ORIGIN OF MAN 215
probably pointed, and capable of movement; and their
bodies were provided with a tail, having the proper mus-
cles. Their limbs and bodies were also acted on by many
muscles which now only occasionally reappear, but are
normally present in the Quadrumana. 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 cecum 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 served 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 membrane. 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 branchiz once existed. In the lunar or weekly
recurrent 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 colunin. These early
ancestors of man, thus seen in the dim recesses of time, must
have been as singly: or even still more simply, organized
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
bears rudiments of various accessory parts, appertaining to
the reproductive system, which properly belong to the oppo-
site 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 verte-
216 THE DESCENT OF MAN
brate kingdom appears to have been hermaphrodite or an-
drogynous.”*
But here we encounter a singular difficulty. In the
mammalian class the males possess rudiments of a uterus
with the adjacent passage, in their vesicule prostatics;
they bear also rudiments of mammz, and some male
Marsupials have traces of a marsupial sac.” Other analo-
gous facts could be added. Are we, then, to suppose that
some extremely ancient mammal continued androgynous,
after it had acquired the chief distinctions of its class, and
therefore after it 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 still existent androgynous forms.” That various, acces-
sory parts, 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, and
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 colors
acquired for battle or ornament by male birds, and in-
herited by the females in an imperfect or rudimentary
condition.
26 This is the conclusion of Prof. Gegenbaur, one of the highest authorities
in comparative anatomy; see ‘‘Grundziige der vergleich. Anat.,’? 1870, s. 876,
The result has been arrived at chiefly from the study of the Amphibia; but it
appears from the researches of Waldeyer (as quoted in ‘‘Journal of Anat. and
Phys.,’’ 1869, p. 161), that the sexual organs of even ‘‘the higher vertebrata
are, in their early condition, hermaphrodite.’’ Similar views have long been
held by some authors, though until recently without a firm basis.
1 The male Thylacinus offers the best instance. Owen, ‘‘Anatomy of
Vertebrates,’’ vol. iii. p. 771.
28 Hermaphroditism has been observed in several species of Serranus, as
well as in some other fishes, where it is either normal and symmetrical or ab-
normal and unilateral. Dr. Zouteveen has given me references on this subject,
more especially to a paper by Prof. Halbertsma, in the ‘‘Transact. of the Dutch
Acad. of Sciences,’’ vol. xvi. Dr. Ginther doubts the fact, but it has now
been recorded by too many good observers to be any longer disputed. Dr. M.
Lessona writes to me that he has verified the observations made by Cavolini
on Serranus. Prof. Ercolani has recently shown (‘‘Accad. delle Scienze,’’
Bologna, Dec, 28, 1871) that eels are androgynous.
THE DESCENT OR ORIGIN OF MAN 217
The possession by male mammals of functionally imper-
fect mammary organs is, in some respects, especially curi-
ous. The 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 prob-
able that the progenitors ot the class also had milk-
secreting glands, but no nipples. This conclusion is sup-
ported by what is known of their manner of develop-
ment; for Professor Turner informs me, on the authority
of Kélliker 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 individual 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 trans-
mitted to the placental mammals.” 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 mammais possessing
mammz? 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. _
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 nour-
ished their young; and in the case of the Marsupials, that
both sexes carried their young in marsupial sacs. This will
not appear altogether improbable, if we reflect that the males
of existing syngnathous fishes receive the eggs of the females
' 99 Prof, Gegenbaur has shown (‘‘Jenaische Zeitschrift,’ B. vii. p. 212)
that two distinct types of nipples prevail throughout the several mammalian
orders, but that it is quite intelligible how both could have been derived from
the nipples of the Marsupials, and the latter from those of the Monotremata.
See, also, a memoir by Dr. Max Huss, on the mammary glands, ibid., B. viii.
p. 176. = ;
Descent—VoL. f.—10
218 : THE DESCENT OF MAN
in their abdominal pouches, hatch them, and afterward, as
some believe, nourish the young; that certain other male
fishes hatch the eggs within their mouths or branchial cavi-
ties; 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 sugges-
tion 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 mam-
mals, can indeed hardly be called rudimentary; they are
merely not fully developed, and not functionally active.
They are sympathetically 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 mamme. 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 mam-
mals aided the females in nursing their offspring,” and that
afterward 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 princi-
30 Mr. Lockwood believes (as quoted in ‘‘Quart. Journal of Science,’’ April,
1868, p. 269), from what he has observed of the development of Hippocampus,
that the walls of the abdominal pouch of the male in some way afford nourish-
ment. On male fishes hatching the ova in their mouths, see a very interesting
paper by Prof. Wyman, in “Proc, Boston Soc. of Nat. Hist., ” Sept. 15, 1857;
also Prof. Turner, in “Journal of Anat, and Phys.,”’ Nov. 1, 1866, p. 78.
Dr. Giinther has likewise described similar cases.
31 Mdlle. C. Royer has suggested a similar view in her ‘‘Origine de
YHomme,”’ ete, 1870.
THE DESCENT OR ORIGIN OF MAN 219
ples of inheritance this state of inactivity would probably
be transmitted to the males at the corresponding age of
maturity. But atan earlier age these organs would be left
unaffected, so that they would be almost equally well devel-
oped in the young of both sexes.
Conclusion.—Von Baer has defined advancement or prog-
ress in the organic scale better than any one else, as resting
on the amount of differentiation and specialization 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 diversified lines of life by means of natu-
ral selection, their parts will have become more and more
differentiated and specialized for various functions, from the
advantage gained by the division of physiological labor, ©
The same part appears often to have been modified first
for one purpose, and then long afterward for some other
and quite distinct purpose; and thus all the parts are ren-
dered more and more complex. But each organism still
retains the general type of structure of the progenitor from
which it was aboriginally derived. In accordance with this
view it seems, if we turn to geological evidence, that organi-
zation 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 sup-
planted, and disappear as soon as they have given birth to
other and more perfect groups. The latter, though victori-
ous over their predecessors, 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 gene-
alogies, by giving us a fair idea of former and lost popula-
tions. But we must not fall into the error of looking at the
existing members of any lowly organized group as perfect
representatives of their ancient predecessors.
220 THE DESCENT OF MAN
The most ancient progenitors in the kingdom of the Ver-
tebrata, at which we are able to obtain an obscure glance,
apparently consisted of a group of marine animals,” resem-
bling the larvee of existing Ascidians. These animals proba-
bly gave rise to a group of fishes, as lowly organized as the
lancelet; and from these the Ganoids, and other fishes like
the Lepidosiren, must have been developed. From such
fish a very small advance would carry us on to the Am-
phibians. 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 steps 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 Lemuride; and the interval is
not very wide from these to the Simiade. The Simiade
8 The inhabitants of the sea-shore must be greatly affected by the tides;
animals living either about the mean high-water mark, or about the mean low-
water mark, pass through a complete cycle of tidal changes in a fortnight.
Consequently, their food supply will undergo marked changes week by week.
The vital functions of such animals, living under these conditions for many
generations, can hardly fail to run their course in regular weekly periods.
Now it isa mysterious fact that in the higher and now terrestrial Vertebrata,
as well as in other classes, many normal and abnormal processes have one or
more whole weeks as their periods; this would be rendered intelligible if the
Vertebrata are descended from an animal allied to the existing tidal Ascidians,
Many instances of such periodic processes might be given, as the gestation of
mammals, the duration of fevers, etc. The hatching of eggs affords also a good
example, for, according to Mr. Bartlett (‘‘Land and Water,’’ Jan. 7, 1871), the
eggs of the pigeon are hatched in two weeks; those of the fowl in three; those
of the duck in four; those of the goose in five; and those of the ostrich in
seven weeks. As far as we can judge, a recurrent period, if approximately
of the right duration for any process or function, would not, when once gained,
be liable to change; consequently it might be thus transmitted through almost
any number of generations. But if the function changed, the period would
have to change, and would be apt to change almost abruptly by a whole week,
This conclusion, if sound, is highly remarkable; for the period of gestation in
each mammal, and the hatching of each bird’s eggs, and many other vital
processes, thus betray to us the primordial birthplace of these animals.
THE DESCENT OR ORIGIN OF MAN 221
then branched off into two great stems, the New World
and Old World monkeys; and from the latter, at a re-
mote 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 a long ©
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 recognize our parent-
age; vor 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 unbiased mind can
study any living creature, however humble, without being
struck with enthusiasm at its marvellous structure and
properties.
222 THE DESCENT OF MAN
CHAPTER VII
ON THE RACES OF MAN
The nature and value of specific characters—Application to the races of
man—Arguments in favor of, and opposed to, ranking the so-called
races of man as distinct species—Sub-species—Monogenists and polyg-
enists—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 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
called races of men; but 1 am about to inquire what
is the value of the differences 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. When-
ever it can be shown, or rendered probable, that the forms
in question have remained distinct for a long period, this
becomes an argument of much weight in favor of treat-
ing them as species. Even a slight degree of sterility be-
tween any two forms when first crossed, or in their offspring,
is generally considered as a decisive test of their specific dis-
tinctness; and their continued persistence without blending
within the same area is usually accepted as sufficient evi-
|" IS not my intention here to describe the several so-
THE DESCENT OR ORIGIN OF MAN 223
dence, 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 of character, for two forms may be highly vari-
able and yet not 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 of the other inhabitants are
specifically distinct, are themselves usually looked at as
distinct; but in truth this affords no aid in distinguishing
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 natu-
ralist 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 re-
marks, although a newly arrived European cannot at first
distinguish the various native races, yet they soon appear
to him extremely dissimilar;' and the Hindu cannot at
first perceive any difference between the several Huropean
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, while others,
as Dr. Rohlfs writes to me, and as I have myself seen, have
Caucasian features. This general similarity is well shown by
~ the French _photographs | in the Collection Anthropologique
du Muséum de Paris of the men belonging to various races,
the greater number of which might pass for Huropeans, as
many persons to whom | have shown them have remarked.
Nevertheless, these men, if seen alive, would undoubtedly
1 «History of India,” 1841, vol. i. p. 323, Father Ripa makes exactly the
epme remark with respect to the Chinese.
224 THE DESCENT OF MAN
appear very distinct, so that we are clearly much influenced
in our judgment by the mere color 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,’ the capacity of the lungs, the form
and capacity of the skull, and even in the convolutions of
the brain.* But it would be an endless task to specify the’
numerous points of difference. ‘The races differ also in
constitution, in acclimatization, 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. Hvery one who has
had the opportunity of comparison must have been struck
with the contrast between the taciturn, even morose, abo-
rigines of South America and the light-hearted, talkative
negroes. There is a nearly similar contrast between the”
Malays and the Papuans,* who live under the same physi-
cal 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 favor 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 woul
at once perceive that they differed in a multitude of char
ters, some of slight and some of considerable importance.
On inquiry he would find that they were adapted to live
under widely different climates, and that they differed some-
? A vast number of measurements of Whites, Blacks, and Indians are given
in the “‘Investigations in “the Military and Anthropolog. Statistics of American
Soldiers,’’ by B. A. Gould, 1869, pp. 298-358; ‘“On the capacity of the lungs,’®
p. 471. See also the numerous and valuable tables, by Dr. Weisbach, from the
observations of Dr. Scherzer and Dr. Schwarz in the ‘Reise der Novara;
Anthropolog. Theil,”? 1867.
3 See, for instance, Mr. Marshall’s account of the brain of a Bushwoman,
in ‘Phil. Transact.,”? 1864, p. 519.
4 Wallace, “The Malay " Archipelago,” vol. ii,, 1869, p. 178.
THE DESCENT OR ORIGIN OF MAN 225
what in bodily constitution and mental disposition. 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 char-
acter for many centuries; and that negroes, apparently iden-
tical with existing negroes, had lived at least 4,000 years
ago.* He would also hear, on the authority of an excellent
observer, Dr. Lund,* that the human skulls found in the
caves of Brazil, intombed with many extinct mammals, be-
longed to the same type as that now prevailing throughout
the American Continent. .
Our naturalist would then perhaps turn to geographical
distribution, and he would probably declare rae ee.
must be distinct species which differ not only in appear-
ance, 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 consid-
erable change of climate; and that the species which come
nearest to man have never been reared to maturity, even
7
5 With respect to the figures in the famous Egyptian caves of Abou-Simbel,
M. Pouchet says (‘‘The Plurality of the Human Races,’’ Eng. translat., 1864,
p. 50) that he was far from finding recognizable representations of the dozen
or more nations which some authors believe that they can recognize. Even
some of the most strongly marked races cannot be identified with that degree
of unanimity which might have been expected from what has been written on
the subject. Thus Messrs, Nott and Gliddon (“‘Types of Mankind,” p. 148)
state that Rameses II., or the Great, has features superbly European; whereas
Knox, another firm believer in the specific distinctness of the races of man
eid of Man,”’ 1850, p. 201), speaking of young Memnon (the same as
meses II., as I am informed by Mr. Birch), insists in the strongest manner
that he is identical in character with the Jews of Antwerp. Again, when
¥ looked at the statue of Amunoph IIL., I agreed with two officers of the estab-
lishment, both competent judges, that he had a strongly marked negro type of
features; but Messrs. Nott and Gliddon (ibid., p. 146, fig. 53) describe him
es a hybrid, but not of ‘‘negro intermixture.”’
6 As quoted by Nott and Gliddon, ‘‘Types of Mankind,” 1854, p. 439.
They give also corroborative evidence; but C. Vogt thinks that the subject
requires further investigation.
226 THE DESCENT OF MAN
under the temperate climate of Europe. He would be
deeply impressed with the fact, first noticed by Agassiz,"
that the different races of man are distributed over the
world in the same zoological provinces as those inhab-
ited by undoubtedly distinct species and genera of mam-
mals, 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 shown,
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 produc-
tions 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 Eskimos, like other Arctic animals, extend
round the whole polar regions. It should be observed that
the amount of difference between the mammals of the sev-
eral zoological provinces does not correspond with the de-
gree 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 conti-
nents from the mammals of the other provinces. Man, it
may be added, does not appear to have aboriginally inhab-
ited any oceanic island; and in this respect he resembles
the other members of his class.
In determining whether the supposed varieties of the
game kind of domestic animal should be ranked as such,
or as specifically distinct, that is, whether any of them are
descended from distinct wild species, every naturalist would
tay 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 | am in-
7 “Diversity of Origin of the Human Races,”’ in the ‘*Christian Examiner, *
July, 1850.
THE DESCENT OR ORIGIN OF MAN 227
formed 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 care-
fully examined the Pediculi collected in different countries
from the different races of man;° and he finds that they
differ not only in color, 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 Pedi-
euli 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 colored, and appeared different from those proper to
the 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 Hastern 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 dis-
tricts. 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 inquire whether the races of
men, when crossed, were in any degree sterile. He might
consult the work® of Prof. Broca, a cautious and philosophi-
al 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
8 “Transact. R. Soc. of Edinburgh,” vol. xxii., 1861, p. 567.
® “Qn the Phenomena of Hybridity in the Geaus Homo,” Eng. translat.,
1864.
228 THE DESCENT OF MAN
asserted that the native women of Australia and Tasmania
rarely produce children to European men; the evidence,
however, on this head has now been shown 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 burned at the same time, whose
remains were found by the police.” Again, it has often
been said that when mulattoes intermarry they produce few
children; on the other hand, Dr. Bachman, of Charleston,"
positively asserts that he has known mulatto families which
have intermarried for several generations, and have contin-
ued on an average as fertile as either pure whites or pure
blacks. Inquiries formerly made by Sir C. Lyell on this’
subject led him, as he informs me, to the same conclusion.”
In the United States the census for the year 1854 included,
according to Dr. Bachman, 405,751 mulattoes; and this
number, considering all the circumstances 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” as
a well-known phenomenon; and this, although a different
10 See the interesting letter by Mr. T. A. Murray, in the ‘‘Anthropolog.
Review,’’ April, 1868, p. lili, In this letter Count Strzelecki’s statement, that
Australian women who have borne children to a white man are afterward
sterile with their own race, is disproved. M. A. de Quatrefages has also
collected (‘Revue des Cours Scientifiques,’’ March, 1869, p. 239) much evi-
dence that Australians and Europeans are not sterile when crossed.
11 “An Examination of Prof. Agassiz’s Sketch of the Nat. Provinces of the
Animal World,’’ Charleston, 1855, p. 44.
12 Dr, Rohlifs writes to me that he found the mixed races in the Great
Sahara, derived from Arabs, Berbers, and Negroes of three tribes, extraordi-
narily fertile. On the other hand, Mr. Winwood Reade informs me that the
negroes on the Gold Coast, though admiring white men and mulattoes, have
a maxim that mulattoes should not intermarry, as the children are few and
sickly. This belief, as Mr. Reade remarks, deserves attention, as white men
have visited and resided on the Gold Coast for four hundred years, so that the
natives have had ample time to gain knowledge through experience.
13 **Military and Anthropolog. Statistics of American Soldiers,’’ by B. A.
Gould, 1869, p. 319.
THE DESCENT OR ORIGIN OF MAN 229
consideration 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 pre-
mature death; but the parents of mulattoes cannot be put
under the category of extremely distinct species. The com-
mon Mule, so notorious for long life and vigor, and yet so
sterile, shows how little necessary connection there is in
hybrids between lessened fertility and vitality; other analo-
gous cases could be cited.
Even if it should hereafter be 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 notsafe—
criterions of specific distinctness. We know that these
qualities are easily affected by changed conditions of life,
or by close interbreeding, 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 fer-
tile. The degrees of sterility do not coincide strictly with
the degrees of difference betwéen the parents in external
structure or habits of life. Man in many respects may be
compared with those animals which have long been domesti-
cated, and a large body of evidence can be advanced in favor
of the Pallasian doctrine, that domestication tends to elimi-
4% “Phe Variation of Animals and 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 incapacity of certain trees to
be grafted together, is incidental on other acquired differences, The nature
of these differences is unknown, but they relate more especially to the repro-
ductive system, and much less so to external structure or to ordinary differences
in constitution. One important element in the sterility of crossed species ap-
parently lies in one or both having been long habituated to fixed conditions;
for we know that changed conditions have a special influence on the reproduc-
tive system, and we have good reason to believe (as before remarked) that the
fluctuating conditions of domestication tend to eliminate that sterility which
is so general with species, in a natural state, when crossed. It has elsewhere
230 THE DESCENT OF MAN
nate the sterility which is so general a result of the crossing
of species in a state of nature. From these several con-
siderations it may be justly urged that the perfect fertility
of the intercrossed races of man, if established, would not
absolutely preclude us from ranking them as distinct species.
Independently of fertility, the characters presented by
the offspring from a cross have been thought to indicate
whether or not the parent-forms ought to be ranked as spe-
cies or varieties; but, after carefully studying the evidence,
I have come to the conclusion that no general rules of this
kind can be trusted. The ordinary result of a cross is the
production of a blended or intermediate form; but in certain
cases some of the offspring take closely after one parent-
form, and some after the other. This is especially apt to
occur when the parents differ in characters which first
appeared as sudden variations or monstrosities."* I refer
to this point because Dr. Rohlfs 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
been shown by me (ibid., vol. ii. p. 185, and ‘‘Origin of Species,’’ 5th edit,
p. 317) that the sterility of crossed species has not been acquired through
natural selection: we can see that when two forms have already been rendered
very sterile, it is scarcely possible that their sterility should be augmented by
the preservation or survival of the more and more sterile individuals; for as the
sterility increases, fewer and fewer offspring will be produced from which to
breed, and at last only single individuals will be produced, at the rarest inter-
vals. But there is even a higher grade of sterility than this. Both Gartner
and Kélreuter have proved that in genera of plants including many species, a
series can be formed from species which when crossed yield fewer and fewer
seeds, to species which never produce a single seed, but yet are affected by the
pollen of the other species, as shown by the swelling of the germen. It is here
manifestly impossible to select the more sterile individuals, which have already
ceased to yield seeds; so that the acme of sterility, when the germen alone is
affected, cannot have been gained through selection. This acme, ard no doubt
the other grades of sterility, are the incidental results of certam unknown
differences in the constitution of the reproductive system of the species which
are crossed.
1% «The Variation of Animals,’’ etc., vol ii. p. 92.
THE DESCENT OR ORIGIN OF MAN 281
inlly justified in ranking the races of man as distinct species;
for he has found that they are distinguished by many differ-
ences in structure and constitution, some being of impor-
tance. 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 natur-
alist were to inquire whether the forms of man keep distinct
like ordinary species, when mingled together in large num-
bers 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 population consisting of Indians
and Spaniards blended in various degrees.’* 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 crossed in all degrees. Many analogous cases
could be added; for instance, in Africa. Hence the races
38 M. de Quatrefages has given (“‘Anthropolog. Review,’’ January, 1869,
p. 22) an interesting account of the success and energy of the Paulistas in
Brazil, who are a much-crossed race of Portuguese and Indians, with a mixture
of the blood of other races.
prone
232 THE DESCENT OF MAN
of man are not sufficiently distinct to inhabit the same-conn-
try without fusion; and the absence of fusion affords the
usual and best test of 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 oc-
curring in any other race, but these are known not to be
of constant occurrence. In the several American tribes,
color and hairiness differ considerably; as does color 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;’7 and so it is with every other character. Now
all naturalists have learned 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 treat-
ing 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 among 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 (Agas-
siz), eleven (Pickering), fifteen (Bory St. Vincent), sixteen.
" For instance with the aborigines of America and Australia. Prof,
Huxley says (‘‘Transact. Internat. Congress of Prehist. Arch.,’’ 1868, p. 105)
that the skulls of many South Germans and Swiss are ‘‘as short and as broad
as those of the Tartars,’’ etc.
THE DESCENT OR ORIGIN OF MAN 233
(Desmoulins), twenty-two (Morton), sixty (Crawfurd), or as
sixty-three, according to Burke."* This diversity of judg-
‘ment does not prove that the races ought not to be ranked
as species, but it shows that they graduate into each other,
and that it is hardly possible to discover clear distinctive
characters between them.
Every naturalist who has had the misfortune to under-
take the description of a group of highly varying organisms
has encountered 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; while 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 dis-
tinct 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 con-
fessed that there are forms, at least in the vegetable king-
dom,” which we cannot avoid naming as species, but which
are connected together by numberless gradations, indepen-
dently of intercrossing.
Some naturalists have lately employed the term ‘‘sub-
species’’ to designate forms which possess many of the
18 See a good discussion on this subject in Waitz, ‘‘Introduct. to Anthro-
pology,’’ Eng. translat., 1863, pp. 198-208, 227. I have taken some of the
above statements from H. Tuttle’s ‘‘Origin and Antiquity of Physical Man,”
Boston, 1866, p. 35. mi : Y
19 Prof. Nageli has carefully described several striking cases in his
“Botanische Mittheilungen,’? B. ii., 1866, s. 294-369. Prof. Asa Gray has
made analogous remarks on some intermediate forms in the Composite of
North America.
234 THE DESCENT OF MAN
characteristics of true species, but which hardly deserve so
high arank. Now if we reflect on the weighty arguments
above given, for raising the races of man to the dignity of |
species, and the insuperable difficulties on the other side
in defining them, it seems that the term ‘‘sub-species’’ might |
here be used with propriety. But from long habit the term |
‘‘race’’ will perhaps always be employed. The choice of
terms is only sb far important in that it is desirable 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, while 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 can generally be arranged in little
groups round other species, like satellites:round planets.”
The question whether mankind consists of one or several
species has of late years been much discussed by anthropolo-
gists, who are divided into the two schools of monogenists
and po lygenists. 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 endeavor 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
90 “Origin of Species,’’ 5th edit., p. 68.
THE DESCENT OR ORIGIN OF MAN 235
represent each other respectively in North America and
Hurope, should be 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 ma-
jority 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 expressing their amount of differ-
ence.” 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 their 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 ques-
tion can arise, for he cannot be said to have been domesti-
cated at any particular period.
During an early stage in the divergence of the races of
man 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 ex-
isting so-called races. Nevertheless, so arbitrary is the term
of species, that such early races would perhaps have been
ranked by some naturalists as distinct species, if their dif-
ferences, 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
21 See Prof. Huxley to this effect in the ‘Fortnightly Review,’’ 1865,
p. 275.
236 THE DESCENT OF MAN
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 sug-
gested by Vogt,” they converged in character. When man
selects the offspring of two distinct species for the same ob-
ject, he sometimes induces a considerable amount of conver-
gence, as far as general appearance is concerned. This is
the case, as shown by Von Nathusius,” 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 gib-
bon 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 sbould have a case of conver-
gence, at least in external characters, for the anthropo-
morphous apes are certainly more like each other in many
points than they are to other apes. All analogical resem-
blances, 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 resemblances. It would, how-
ever, be extremely rash to attribute to convergence close
similarity of character in many points of structure among
the modified descendants of widely distinct beings. The
form of a crystal is determined solely by the molecular
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 de-
pends on an infinity of complex relations, namely, on varia-
tions due to causes far too intricate to be followed—on the
nature of the variations preserved, these depending on the
2 “Tectures on Man,’ Eng. translat., 1864, p. 468.
23 "Die Racen des Schweines,’’ 1860, s. 46. ‘‘Vorstudien fiir Geschichte,
etc., Schweineschaédel,’? 1864, s. 104. With respect to cattle, see M. de
Quatrefages, ‘‘Unité de l’Espéce Humaine,’’ 1861, p. 119.
THE DESCENT OR ORIGIN OF MAN 237
physical conditions, and still more on the surrounding or-
ganisms which compete with each—and lastly, on inheri-
tance (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 organisms, if these
differed from each other in a marked manner, should ever
afterward converge so closely as to lead to a near approach
to identity throughout their whole organization. In the
case of the convergent races of pigs above referred to, evi-
dence of their descent from two primitive stocks is, accord-
ing 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 re-
spects, as in color, hair, shape of skull, proportions of the
body, etc., yet, if their whole structure be taken into con-
sideration, 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 independently acquired by abo-
riginally distinct species or races. The same remark holds
good with equal or greater force with respect to the numer-
ous 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,
while living with the Fuegians on board the ‘‘Beagle,”’ with
the many little traits of character showing how similar their
minds were to ours; and so it was with a full-blooded negro
with whom I happened once to be intimate.
238 THE DESCENT OF MAN
He who will read Mr. Tylor’s and Sir J. Lubbock’s
interesting works” can hardly fail to be deeply impressed
with the close similarity between the men of all races in
tastes, dispositions, and habits. This is shown by the
pleasure which they all take in dancing, rude music, act-
ing, painting, tattooing, and otherwise decorating them-
selves; 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
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,* 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 fact can only be accounted for by the
various races having similar inventive or mental powers.
The same observation has been made by archeologists”
with respect to certain widely prevalent ornaments, such
as zigzags, etc.; and with respect to various simple beliefs
and customs, such as the burying of the dead under mega-
lithic structures. I remember observing in South America,”
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
24 Tylor’s ‘‘Early History of Mankind,’’ 1865; with respect to gesture-
language, see p. 54. Lubbock’s ‘‘Prehistoric Times,”’ 2d edit., 1869.
25 “On Analogous Forms of Implements,’’ in ‘‘Memoirs of Anthropolog,
Soc.,”? by H. M. Westropp. ‘‘The Primitive Inhabitants of Scandinavia,”
Eng. translat., edited by Sir J. Lubbock, 1868, p. 104.
26 Westropp, ‘“‘On Cromlechs,”’ etc., “‘Journal of Ethnological Soc.,”’ as
given in ‘‘Scientific Opinion,’’ June 2, 1869, p. 3.
21 “Journal of Researches: Voyage of the Beagle,”’ p. 46.
THE DESCENT OR ORIGIN OF MAN 289
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 structure and mental faculties (I do not here refer
to similar customs) should all have been independently
acquired, they must have 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, preceded 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. Lub-
bock, after comparing the arts now practiced 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 learned they would never have been for-
gotten.” He thus shows that ‘‘the spear, which is but a
development of the knife-point, and the club, which is but
along hammer, are the only things left.’” He admits, how-
ever, 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 aid of
canoes, to have spread widely. Sir J. Lubbock further re-
marks how improbable it is that our earliest ancestors could
have ‘‘counted as high as ten, considering that so many
races now in existence cannot get beyond four.’’ Neverthe-
less, at this early period, the intellectual and social faculties
% “Prehistoric Times,’’ 1869, p. 574.
240 THE DESCENT OF MAN
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 lan-
_guages, 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. Without the use of some language,
however imperfect, it appears doubtful whether man’s in-
tellect 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 lan-
guage 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 polygenists will die a silent and unob-
served 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 pro-
genitors. With our domestic animals a new race can readily
be formed by carefully matching the varying offspring from
%
=
THE DESCENT OR ORIGIN OF MAN 241
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 individuals 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 pro-
duced 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,
while those which have run wild on the Pampas have ac-
quired larger and coarser heads; and such changes are mani-
festly due, not to any one pair, but to all the individuals
having been subjected to the same conditions, aided, per-
haps, 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 modifica-
tions 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 inhab-
itants, indicate much extinction. Some small and broken
tribes, remnants of former races, still survive in isolated and
generally mountainous districts. In Europe the ancient
Descent—Vo. I.—11
| This race is
| modern, that we have ever heard of.’ * It differed, there-
242 THE DESCENT OF MAN
races were all, according to Schaaffhausen,” ‘‘lower in the
scale than the rudest living savages’; they must therefore
have differed, to a certain extent, from any existing race.
The remains described by Prof. Broca from Les Eyzies,
though they unfortunately appear to have belonged to a
single family, indicate a race with a most singular com-
bination of low or simious, and of high characteristics.
“entirely different from any other, ancient or
fore, from the quaternary race of the caverns of Belgium.
Man can long resist conditions which appear extremely
unfavorable for his existence. 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 without 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.
Extinction follows chiefly from the competition of tribe
with tribe, and race with race. Various checks are always
in action, serving to keep down the numbers of each sav-
age tribe—such as periodical famines, nomadic habits, and
the consequent deaths of infants, prolonged suckling, wars,
accidents, sickness, licentiousness, 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
29 Translation in ‘‘Anthropological Review,’’ October, 1868, p. 431.
2 ‘Transact. Internat. Congress of Prehistoric Arch.,’? 1868, pp. 172-15.
See also Broca (translation) in ‘‘ Anthropological Review,’’ October, 1868, p. 410.
81 Dr, Gerland ‘‘Ueber das Aussterben der Naturvélker,’’ 1868, s. 82.
THE DESCENT OR ORIGIN OF MAN 243
decrease, it generally goes on decreasing until it becomes
extinct.”
When civilized 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 vic-
tory of civilized 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;* and so it may be with the evil
effects from spirituous liquors, as well as with the uncon-
querably strong taste for them shown by so many savages.
It further appears, mysterious as is the fact, that the first
Co. of distinct and separated peoples generates disease.™
Mr. Sproat, who in Vancouver Island closely attended to
the subject of extinction, believed that changed habits of
life, consequent on the advent of Huropeans, 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 new ones in their place.’’ *
The grade of their civilization seems to be a most impor-
tant element in the success of competing nations. A few
enturies ago Europe feared the inroads of Hastern barba-
| rans 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 civilized nations; had they done so,
82 Gerland (‘Ueber das Aussterben der Naturvélker,’’ 1868, s. 12) gives
facts in support of this statement.
38 See remarks to this effect in Sir H. Holland’s ‘‘Medical Notes and Reflec-
tions,’’ 1839, p. 390.
24 I have collected (‘‘Journal of Researches: Voyage of the Beagle,”
p. 435) a good many cases bearing on this subject; see also Gerland (ibid.,
8. 8). Poeppig speaks of the ‘‘breath of civilization as poisonous to savages.”
Sproat, “Scenes and Studies of Savage Life,’’ 1868, p. 284.
244 THE DESCENT OF MAN
Kp the old moralists would have mused over the event; but
i there is no lament in any writer of that period over the
perishing barbarians.*° The most potent of all the causes
of extinction appears in many cases to be lessened fertility
and ill-health, especially among the children, arising from
changed conditions of life, notwithstanding that the new
conditions may not be injurious in themselves. J am much
indebted to Mr. H. H. Howorth for having called my atten-
tion to this subject, and for having given me information
respecting it. I have collected the following cases.
When Tasmania was first colonized the natives were
roughly estimated by some at 7,000, 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,*” who were in 1882 trans-
ported 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 suffered
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. As they continued rapidly to decrease,
my 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 con-
sisted (December 20, 1847) of fourteen men, twenty-two
women, and ten children. 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
36 Bagehot, ‘‘Physics and Politics,’’ ‘‘Fortnightly Review,” April 1, 1868,
p. 455.
37 All the statements here given are taken from ‘‘The Last of the Tas-
manians,’’ by J. Bonwick, 1870.
% This is the statement of the Governor of Tasmania, Sir. W. Denison,
“Varieties of Vice-Regal Life,”? 1870, vol. i. p. 6%.
THE DESCENT OR ORIGIN OF MAN 245
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. 886) that only two
had ever borne children: and these two had together pro-
things, Dr. Story remarks that death followed the attempts
to civilize 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 deathsnumerous. 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. 888, 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 repro-
duction 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 Mur-
chison River, twelve died of consumption within three
months. *
The decrease of the Maories of New Zealand has been
carefully investigated by Mr. Fenton, in an admirable Re-
port, from which all the following statements, with one
exception, are taken.*® The decrease in number since 1830
is admitted by every one, including the natives themselves,
and is still steadily progressing. Although it has hitherto
been found impossible to take an actual census of the na-
tives, their numbers were carefully estimated by residents
- 39 For these cases, see Bonwick’s ‘‘Daily Life of the Tasmanians,” 1870,
p. 90; and ‘The Last of the Tasmanians,’’ 1870, p. 386. :
40 “Observations on the Aboriginal Inhabitants of New Zealand,”’ published
by the Government, 1859,
»
246 THE DESCENT OF MAN
in many districts. The result seems trustworthy, and shows
that during the fourteen years previous to 1858 the decrease
was 19.42 per cent. Some of the tribes thus carefully ex-
amined 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 num-
ber in 1858 was believed to be 58,700, and in 1872, after a
second interval of fourteen years, another census was taken,
and the number is given as only 36,359, showing a decrease
of 32.29 per cent!** Mr. Fenton, after showing in detail the
insufficiency of the various causes usually assigned in expla-
nation of this extraordinary decrease, such as new diseases,
the profligacy of the women, drunkenness, wars, etc., con-
cludes 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 shows (p. 83) 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. Fen-
ton contrasts with astonishment the decrease in New Zealand
with the increase in Ireland—countries not very dissimilar in
climate, and where the inhabitants now follow nearly similar
habits. The Maories themselves (p. 35) ‘‘attribute their de-
cadence, 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 shows (p. 40) that about 1830 the art of manu-
facturing putrid corn (maize), by long steeping in water,
was discovered and largely practiced; and this proves that
a change of habits was beginning among the natives even
4 “New Zealand,’’ by Alex. Kennedy, 1873, p. 47.
THE DESCENT OR ORIGIN OF MAN 247
when New Zealand was only thinly inhabited by Europeans.
When I visited the Bay of Islands in 1885, 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,*? that the Melanesians of the New Hebrides and
neighboring archipelagoes suffered to an extraordinary de-
gree in health, and perished in large numbers, when they .
were 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
Tslands 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 sever-
al subsequent periods, an accurate census was officially taken,
\ but I have been able to obtain only the following returns:
\
Native Porutation. {Annual rate of decrease per
— cent, assuming it to have
(Except during 1832 and| been uniform between the
Year. 1836, when the few for-| successive censuses; these
eigners in the islands} censuses being taken at ir-
were included.) regular intervals.
DOB Diss isccevessondecteeesadeactae 130,313
} 4.46
TRS Giccsiwasseacereataneaccn sees 108,579
t 2.47
LEDS sicaesrinprcnesenesidosscincaces 71,019
t 0.81
L860 wieawosedacdeverssines: saeneus 67,084
2.18
TS GCi, cicesosss cndonanecanciaesse 58,765
- 2.17
LST Qi ssvciedasgansicaendenceoabees 51,531
We here see that in the interval of forty years, between
1832 and 1872, the population has decreased no less than
2 “Tife of J. C. Patteson,’’? by C. M. Monge, 1874; see more especially
- vol. i. p. 530.
248 THE DESCENT OF MAN
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 labor imposed on conquered tribes
and to newly introduced diseases, which have been on sev-
eral occasions extremely destructive. No doubt these and
other such causes have been highly efficient, and may ae-
count 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. Ruschen-
berger of the U. S. Navy, who visited these islands between
1835 and 1837, in one district of Hawaii, only twenty-five
men out 1,184, and in another district only ten out of 687,
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 island.’’ This is almost
exactly the same average as with the Tasmanians at Oyster
Cove. Jarves, who published his History in 1848, says that
‘‘families who have three children are freed from all taxes;
those having more, are rewarded by gifts of land and other
encouragements.’’ This unparalleled enactment by the gov-
ernment well shows 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 weakness of constitution in the
children, in relation to the lessened fertility of their parents.
There is, moreover, a further resemblance 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 25,247
females of all ages, that is 125.386 males for every 100 fe-
;-mnales; whereas in all civilized countries the females exceed
\ the males. No doubt the profligacy of the women may in
part account for their small fertility; but their changed hab-
its of life is a much more probable cause, and which will at
THE DESCENT OR ORIGIN OF MAN 249
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 civilized of the Pacifie 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 Englishmen
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 inconsider-
able, I can well believe, from what is known with respect
to animals, that they might suffice to lessen the fertility of
the natives.**
Lastly, Mr. Macnamara states“ that the low and degraded
inhabitants of the Andaman Islands, on the eastern side of
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.’’ He further states that the
inhabitants of the Valley of Nepal, which is extremely hot
4 The foregoing statements are taken chiefly from the following works
“Jarves’s History of the Hawaiian Islands,’’ 1843, pp. 400-407. Cheever,
“Life in the Sandwich Islands,’’ 1851, p, 277. Ruschenberger is quoted by
Bonwick, ‘‘Last of the Tasmanians,’’ 1870, p. 378. Bishop is quoted by Sir
E. Belcher, ‘‘Voyage Round the World,’’ 1843, vol. i. p. 272. I owe the
census of the several years to the kindness of Mr. Coan, at the request of
Dr. Youmans, of New York; and in most cases I have compared the Youmans
figures with those given in several of the above-named works. I have omitted
the census for 1850, as I have seen two widely different numbers given.
#4 “The Indian Medica} Gezette,’’ November 1, 1871, p. 240.
250 THE DESCENT OF MAN
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 condi-
tions or habits of life, and not exclusively from being trans-
ported 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 particu-
larly liable to suffer. It has often been said, as Mr. Mac-
namara remarks, that man can resist with impunity the
greatest diversities of climate and other changes; but this
is true only of the civilized races. Man in his wild condi-
tion seems to be in this respect almost as susceptible as his
nearest allies, the anthropoid apes, which have never yet
survived long, when removed from their native 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 de-
gree 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
shown that this explanation by no means suffices 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 interbreeding; but in the above cases
infertility has coincided too closely with the arrival of Euro-
peans for us to admit this explanation. Nor have we ar
present any reason to believe that man is highly sensitive
to the evil effects of interbreeding, especially in areas so
_ THE DESCENT OR ORIGIN OF MAN 251
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.*®
A much more probable view is suggested by the analogy
of the lower animals. The reproductive system can be
shown 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 chapter
xviii. of volume ii. of my ‘‘Variation of Animals and Plants
under Domestication.’’ I 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,
vigor, and fertility of most or all organic beings, while
other changes are known to render a large number of ani-
mals 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 instance, because of their relationship to
man. It is remarkable how slight a change in the condi-
tions 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.** Certain groups of
45 On the close relationship of the Norfolk Islanders, see Sir W. Denison,
“Varieties of Vice-Regal Life,’? vol. i., 1870, p. 410. For the Todas, see
Colonel Marshall’s work, 1873, p. 110. For the Western Islands of Scotland,
Dr. Mitchell, ‘Edinburgh Medical Journal,’’? March to June, 1865.
4 For the evidence on this head, see ‘‘Variation of Animals,”’ etc., vol. ii,
p- 111.
252 THE DESCENT OF MAN
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, while the others
are not so; on the other hand, a single species may retain its
fertility while 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 off-
spring, 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
inhabited 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.
Civilized races can certainly resist changes of all kinds far
better than savages; and in this respect they resemble do-
mesticated animals, for though the latter sometimes suffer
in health (for instance, Kuropean dogs in India), yet they
are rarely rendered sterile, though a few such instances
have been recorded.” The immunity of civilized races and
domesticated animals is probably due to their having been
47 “Variation of Animals,” ete., vol. ii, p. 16,
o
THE DESCENT OR ORIGIN OF MAN 258
subjected to a greater extent, and therefore having grown
somewhat more accustomed, to diversified or varying con-
ditions, 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
intercrossed. It appeats that a cross with civilized 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 increased so rapidly that, although sixteen of them
returned to Pitcairn Island in 1859, they numbered in
January, 1868, 800 souls—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 800;
whereas the Tasmanians decreased during fifteen years from
120 to 46, of which latter number only ten were children.
So again in the interval between the census of 1866 and
1872 the natives of full blood in the Sandwich Islands
decreased by 8,081, while the half-castes, who are believed
to be healthier, increased by 847; but I do not know
whether the latter number includes the offspring 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 civilized 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 homes and to change their habits. It is an in-
teresting circumstance that the chief check to wild animals
4 These details are taken from ‘‘The Mutineers of the Bounty,’’ by Lady
Belcher, 1870; and from ‘‘Pitcairn Island,’’ ordered to be printed by the House
of Commons, May 29, 1863. The following statements about the Sandwich
Islanders are from the ‘‘Honolulu Gazette,’’ and from Mr. Coan.
254 THE DESCENT OF MAN
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 civilization, sur-
viving to form a civilized 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 pre-
sented by the extinction of one of the higher animals—of
the fossil horse, for instance, which disappeared from South
America, soon afterward to be replaced, within the same
districts, by countless troops of the Spanish horse. The
New Zealander seems conscious of this parallelism, for, he
compares his future fate with that of the native rat now
almost exterminated by the European rat. Though the
difficulty is great to our imagination, and really great, if
we wish to ascertain the precise causes and their manner
of action, it ought not to be so to our reason, as long as 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 decrease in number; and decreasing numbers
will sooner or later lead to extinction; the end, in most
cases, being promptly determined by the inroads of con-
quering tribes.
On the Formation of the Races of Man.—In some cases
the crossing of distinct races has led to the formation of
anew race. The singular fact that Europeans and Hindus,
who belong to the same Aryan stock, and speak a language
fundamentally the same, differ widely in appearance, while
Europeans differ but little from Jews, who belong to the
Semitic stock, and speak quite another language, has been
accounted for by Broca,* through certain Aryan branches
49 “On Anthropology,” translation, ‘‘Anthropolog. Review,’ Jan. 1868,
p. 38.
THE DESCENT OR ORIGIN OF MAN 255
having been largely crossed by indigenous tribes during
their wide diffusion. When two 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-
colored Brahmin, with his intellectual brow, calm eyes, and
high but narrow head;’’ so that it is necessary in courts
of justice to ask the witnesses whether they are Santalis or
Hindus.” Whether a heterogeneous people, such as the
inhabitants 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” in the course of a few genera-
tions, we may infer that the free intercrossing of a hetero-
geneous 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 homo-
geneous, 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 color
’ of the skin is the most conspicuous and one of the best
marked. It was formerly thought that differences of this
kind could be accounted for by long exposure to different
climates; but Pallas first showed that this is not tenable,
and he has since been followed by almost all anthropolo-
gists. This view has been rejected chiefly because the dis-
tribution of the variously colored races, most of whom must
have long inhabited their present homes, does not coincide
50 ‘*Annals of Rural Bengal,’’ 1868, p. 134.
51 “The Variation of Animals and Plants under Domestication,”’ vol. ii.
52 Pallas, ‘Act. Acad. St. Petersburg,’’ 1780, part ii. p. 69. He was fol-
lowed by Rudolphi, in his ‘‘Beytrage zur Anthropologie,”’ 1812. An excellent
summary of the evidence is given by Godron, ‘‘De l’Espéce,’’ 1859, vol. ii,
p. 246, ete.
256 THE DESCENT OF MAN
with corresponding differences of climate. Some little
weight may be given to such cases as that of the Dutch
| families, who, as we hear on excellent authority, have not
undergone the least change of color after residing for three
centuries in South Africa. An argument on the same side
may likewise be drawn from the uniform appearance in
various parts of the world of gypsies and Jews, though the
uniformity of the latter has been somewhat exaggerated.”
A very damp or a very dry atmosphere has been supposed
to be more influential in modifying the color 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 con-
clusion on this head must be considered as very doubtful.®
Various facts, which I have given elsewhere, prove that
the color of the skin and hair is sometimes correlated in
a surprising 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 afterward found that this same idea had long ago
occurred to Dr. Wells. It has long been known that ne-
groes, and even mulattoes, are almost completely exempt
from the yellow fever, so destructive in tropical America.”
They likewise escape to a large extent the fatal intermittent
53 Sir Andrew Smith, as quoted by Knox, ‘‘Races of Man,’’ 1850, p. 473.
54 See De Quatrefages on this head, ‘‘Revue des Cours Scientifiques,’’ Oct.
17, 1868, p. 731.
55 Livingstone’s ‘‘Travels and Researches in 8, Africa,’’ 1857, pp. 338, 329.
D’Orbigny, as quoted by Godron, ‘‘De l’Espéce,”’ vol. ii. p. 266.
58 See a paper read before the Royal Soc. in 1818, and published in his
Essays in 1818. I have given an account of Dr. Wells’s views in the Historical
Sketch (p. xvi.) to my ‘‘Origin of Species.’? Various cases of color correlated
with constitutional peculiarities are given in my ‘‘Variation of Animals
ander Domestication,’ vol. ii. pp. 227, 335.
51 See, for instance, Nott and Gliddon, ‘‘Types of Mankind,’’ p. 68.
THE DESCENT OR ORIGIN OF MAN 257
fevers that prevail along at least 2,600 miles of the shores of
Africa, and which annually cause one-fifth of the white set-
tlers to die, and another fifth to return home invalided.”
This immunity in the negro seems to be partly inherent,
depending on some unknown peculiarity of constitution,
and partly the result of acclimatization. Pouchet® states
that the negro regiments recruited near the Soudan, and
borrowed from the Viceroy of Egypt for the Mexican war,
escaped the yellow fever almost equally with the negroes
originally brought from various parts of Africa and accus-
tomed to the climate of the West Indies. That acclimatiza-
tion plays a part is shown by the many cases in which ne-
groes have become somewhat liable to tropical fevers after
having resided for some time in a colder climate.” The
nature of the climate under which the white races have
long resided likewise has some influence on them; for dur-
ing 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 acclimatization, implies exposure during a prodig-
ious length of time; for the aborigines of tropical America
who have resided there from time immemorial are not ex-
empt from yellow fever; and the Rev. H. B. Tristram states
that there are districts in Northern Africa which the native
inhabitants are compelled annually to leave, though the
negroes can remain with safety.
That the immunity of the negro is in any degree corre-
lated with the color of his skin is a mere conjecture: it may
be correlated with some difference in his blood, nervous
system, or other tissues. Nevertheless, from the facts above
alluded to, and from some connection apparently existing
88 Major Tulloch, in a paper read before the Statistical Society, April 20,
1840, and given in the ‘‘Athenzeum,”’ 1840, p. 353.
59 “The Plurality of the Human Race”? (translat.), 1864, p. 60.
6 Quatrefages, ‘‘Unité de l’Espéce Humaine,” 1861, p. 205. Waita,
“Introduct. to Anthropology,’’ translat., vol. i., 1863, p. 124. Livingstone
gives analogous cases in his ‘‘Travels.”’
258 THE DESCENT OF MAN
between complexion and a tendency to consumption, the
conjecture seemed to me not improbable. Consequently I
endeavored, with but little success,” to ascertain how far
it holds good. The late Dr. Daniell, 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 experi-
enced 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-colored Europeans escape the yellow
fever more than those that are light-colored. 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 selec-
tion of men for service on the coast of Africa, to choose
those with red hair.” As far, therefore, as these slight
61 In the spring of 1862 I obtained permission from the Director-General of
the Medical Department of the Army to transmit to the surgeons of the various
regiments on foreign service a blank table, with the following appended re-
marks, but I have received no returns. ‘‘As several well-marked cases have
been recorded with our domestic animals of a relation between the color of the
dermal appendages and the constitution, and it being notorious that there is
some limited degree of relation between the color of the races of man and the
climate inhabited by them, the following investigation seems worth considera-
tion: Namely, whether there is any relation in Europeans between the color
of their hair and their liability to the diseases of tropical countries. If the
surgeons of the several regiments, when stationed in unhealthy tropical dis-
tricts, would be so good as first to count, as a standard of comparison, how
many men, in the force whence the sick are drawn, have dark and light-colored
hair, and hair of intermediate or doubtful tints; and if a similar account were
kept by the same medical gentlemen, of all the men who suffered from malarious
and yellow fevers, or from dysentery, it would soon be apparent, after some
thousand cases had been tabulated, whether there exists any relation between
the color of the hair and constitutional liability to tropical diseases. Perhaps
no such relation would be discovered, but the investigation is well worth
making. In case any positive results were obtained, it might be of some prac-
tical use in selecting men for any particular service. Theoretically the result
would be of high interest, as indicating one means by which a race of men
inhabiting from a remote period an unhealthy tropical climate, might have
become dark-colored by the better preservation of dark-haired or dark-com-
plexioned individuals during a long succession of generations.”’
62 **Anthropological Review,’’? Jan. 1866, p. xxi. Dr. Sharpe also says,
with respect to India (‘‘Man a Special Creation,’’ 1873, p. 118), that “it has
THE DESCENT OR ORIGIN OF MAN 259
indications go, there seems no foundation for the hypothe-
sis that blackness has resulted from the darker and darker
individuals having survived better during long exposure
to fever-generating miasma.
Dr. Sharpe remarks, 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, although larger than freckles, and that
these patches were never affected by sun-burning, while 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. Whether the saving of the skin from
being thus burned is of sufficient importance 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-colored Hindus 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 we cannot account
for the differences of color in the races of man, through any
been noticed by some medical officers that Europeans with light hair and florid
complexions suffer less from diseases of tropical countries than persons with
dark hair and sallow complexions; and, so far as I know, there appear to be
good grounds for this remark.’? On the .other hand, Mr. Heddle, of Sierra
Leone, ‘‘who has had more clerks killed under him than any other man,”’ by
the climate of the West African Coast (W. Reade, ‘‘African Sketch Book,”’
vol. ii. p. 522), holds a directly opposite view, as does Capt. Burton.
6 “*Man a Special Creation,’’ 1873, p. 119.
‘Variation of Animals and Plants under Domestication,’’ vol. ii. pp.
836, 337.
AG
260 THE DESCENT OF MAN
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. *
We have seen in the second chapter that the conditions
of life affect the development of the bodily frame in a direct
manner, and that the effects are transmitted. Thus, as is
generally admitted, the European settlers in the United
States undergo a slight but extraordinarily rapid change of
appearance. Their bodies and limbs become elongated; and
I hear from Colonel 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 regi-
ments, 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 considerable body
of evidence showing that in the Southern States the house-
slaves of the third generation present a markedly different
_appearance from the field-slaves.”
If, however, we look to the races of man as distributed
over the world, we must infer that their characteristic dif-
ferences cannot be accounted for by the direct action of
different conditions of life, even after exposure to them for
an enormous period of time. The Eskimos live exclusively
on animal food; they are clothed in thick fur, and are ex-
posed 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 productions of their
6 See, for instance, Quatrefages (“‘Revue des Cours Scientifiques,’’ Oct.
10, 1868, p. 724) on the effects of residence in Abyssinia and Arabia, and
other analogous cases. Dr. Rolle (‘‘Der Mensch, seine Abstammung,”’ etc.,
1865, s. 99) states, on the authority of Khanikof, that the greater number of
German families settled in Georgia have acquired in the course of two genera-
tions dark hair and eyes. Mr. D. Forbes informs me that the Quichuas in the
Andes vary greatly in color, according to the position of the valleys inhabited
by them.
J 66 Harlan, ‘‘Medical Researches,’’ p. 532. Quatrefages (‘‘Unité de l’Espéce
Humaine,’’ 1861, p. 128) has collected much evidence on this head.
THE DESCENT OR ORIGIN OF MAN 261
mhospitabre 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 b
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 habitually live in canoes may have their
legs somewhat stunted; those who inhabit lofty regions may
_ have their chests enlarged; 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 civilized nations, the
reduced size of the jaws from lessened use—the habitual
play of different muscles serving to express different emo-
tions—and the increased size of the brain from greater intel-
lectual activity, have together produced a considerable effect
n their general appearance when compared with savages.” 7
Increased bodily stature, without any corresponding increase
in the size of the brain, may (judging from the previously
adduced case of rabbits) have given to some races an elon-
gated skull of the dolichocephalic type.
Lastly, the little-understood principle of correlated devel-
opment has sometimes come into action, as in the case of
great muscular development and strongly projecting supra-
orbital ridges. The color of the skin and hair are plainly
correlated, as is the texture of the hair with its color in the
Mandans of North America. The color also of the skin,
81 See Prof. Schaaffhausen, translat. in ‘‘Anthropological Review,’’ Oct.
1868, p. 429.
§ Mr. Catlin states (‘‘N. American Indians,’’ 3d edit., 1842, vol. i. p. 49)
that in the whole tribe of the Mandans, about one in ten or twelve of the
members, of all ages and both sexes, have bright silvery gray hair, which is
,
262 THE DESCENT OF MAN
and the odor) 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 execretory
pores are related. If we may judge from the analogy of
our domesticated animals, many modifications of struct-
ure in man probably come under this principle of correlated
development. =
We have now seen that the external characteristic differ-
ences between the races of man cannot be accounted for in a
satisfactory 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. We are therefore led
to inquire whether slight individual differences, to which
man is eminently liable, may not have been preserved and
augmented during a long series of generations through natural
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
his head, none of the differences between the races of man
[re of any direct or special service to him. The intellec-
tual 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
variations being of an indifferent nature, and to their hav-
ing thus 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
hereditary. Now this hair is as coarse and harsh as that of a horse’s mane,
while the hair of other colors is fine and soft.
68 On the odor of the skin, Godron, ‘‘Sur l’Espéce,’’ tom. ii. p. 217. On
the pores in the skin, Dr. Wilckens, ‘‘Die Aufgaben der Landwirth. Zootechnik,’’
1869, s. 7.
‘
STRUCTURE OF THE BRAIN 263
there remains one important agency, namely Sexual Selec-
tion, which appears to have acted powerfully on man, as on
many other animals. Ido 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 individuals are con-
tinually 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 unknown
agencies which induced them were to act in a more constant
manner, aided by long-continued intercrossing. Such varia-
tions come under the provisional class alluded to in our sec-
ond chapter, which for the want of a better term are often
called spontaneous. Nor do TI pretend that the effects of
sexual selection can be indicated with scientific precision;
but it can be shown 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 shown that the differences between the races of
man, as in color, hairiness, form of features, etc., are of a
kind which might have been expected to come under the
influence of sexual selection. But in order to treat this sub-
ject 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 show 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 Pror. Huxusy, F.R.S.
THE controversy respecting the nature and the extent of
the differences 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
264 THE DESCENT OF MAN
present, totally different from what it was formerly. It
was originally asserted and reasserted, with singular perti-
nacity, that the brain of all the apes, even the highest, dif-
fers 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 developed in apes’ as in human brains, or even better;
and that it is characteristic 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 compara-
tive anatomy. Moreover, it is admitted by every one of the
long series of anatomists who, of late years, have paid spe-
cial attention to the arrangement of the complicated sulci and
gyri which appear upon the surface of the cerebral hemi-
spheres in man and the higher a ke that they are si on
after the very same pattern in him, as in them. KHvery
principal gyrus and sulcus of a chimpanzee’s brain is clearl
represented in that of a man, so that the terminology whic
applies to the one answers for the other. On this point there
is no difference of opinion. Some ‘ie be since, Prof. Bischoff
published a memoir” 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 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 organization,
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 organization alone, no one probably would ever
have disputed the view of Linnzus, that man should be
placed, merely as a peculiar species, at the head of the mam-
malia and of those apes. Both show, in all their organs, so
close an affinity, that the most exact anatomical investiga-
tion 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’ (1. ¢., p. 101).
7 ‘Die Grosshirn-Windungen des Menschen;” ‘‘Abhandlungen der K.
Bayerischen Akademie,’’ Bd. x., 1868.
STRUCTURE OF THE BRAIN 265
There remains, then, no dispute as to the resemblance.
in fundamental characters, between the ape’s brain an
man’s; nor any as to the wonderfully close similarity be-
tween 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 of the highest apes and that of man, is there any seri-
ous question as to the nature and extent of these differences.
It is admitted that the man’s cerebral hemispheres are abso-
lutely and relatively larger than those of the orang and chim-
panzee; that his frontal lobes are less excavated by the up-
ward 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 per-
endicular” fissure, which is usually so strongly marked a
eature of the ape’s brain, is but faintly marked. But it is
also clear that none of these differences constitute 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, Prof. Turner remarks:”
‘In some brains it long simply as an indentation of
the margin of the hemisphere, but, in others, it extends for
some distance more or less transversely outward. 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 outward,
and then extended downward 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 distinctness in the brain of most Quadru-
mana, is owing to the presence, in the former, of certain su-:
erficial, well-marked, secondary convolutions which bridge
it over and connect the parietal with the occipital lobe. The
closer the first of these Brdgig ri lies to the longitudinal
fae ue shorter is the sciraal parieto-occipital fissure”’
« Gay Pe 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 con-
stant character of the higher ape’s brain. For, in the chim-
panzee, the more or less extensive obliteration of the exter-
~ 1 “Convolutions of the Human Cerebrum Topographically Considered,”
1866, p. 12.
Descent—Vou. L—12
266 THE DESCENT OF MAN
nal perpendicular suleus by ‘‘bridging convolutions,'’ on one
side or the other, has been noted over and over again by
Prof. Rolleston, Mr. Marshall, M. Broca, and Prof. Turner.
At the conclusion of a special paper on this subject the
latter writes :” ;
‘The three specimens of the brain of a chimpanzee just
described, prove that the generalization which Gratiolet has
attempted to draw of the complete absence of the first con-
necting 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 speci-
men did the brain, in these particulars, follow the law which
Gratiolet has expressed. As regards the presence of the
ae bridging convolution, I am inclined to think that
it has existed in one hemisphere, 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
want believe, only been seen in the brain (A) recorded in
this communication. The asymmetrical arrangement in the
convolutions of the two hemispheres, which previous ob-
servers have referred to in their descriptions, is also well
illustrated in these specimens’ (pp. 8, 9).
Even were the presence of ths temporo-occipital, or ex-
ternal perpendicular, 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 tem-
ee is one of the most constant of sulci in the
atarrhine or Old World apes, it is never very strongly de-
veloped in the New World apes; it is absent in the smaller
Platyrhini; rudimentary in Pithecta;"* and more or less
obliterated by bridging convolutions in Afeles.
A character which is thus variable within the limits of
a single group can have no great taxonomic value.
It is further established that the degree of asymmetry
of the convolution of the two sides in the human brain is
ubject 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 considerably
72 Notes more especially on the bridging convolutions in the Brain of the |
Chimpanzee, ‘‘Proceedings of the Royal Society of Edinburgh,’’ 1865-66.
7% Flower ‘On the Anatomy of Pithecia Monachus,’’ ‘‘Proceedings of the
Zoological Society,’’ 1862.
STRUCTURE OF THE BRAIN 267
less complicated and more symmetrical than in the Euro-
pean 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 chim-
ae aes yy M. Broca. (‘‘L’Ordre des Primates,”
ii , 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
chimpanzee’s or orang’s brain.
oreover, there is one circumstance in which the orang’s
and chimpanzee’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.
n view of these facts I do not hesitate in this year 1874
to repeat and insist upon the proposition which [ enunciated
in 1863:”
‘‘So far as cerebral structure goes, therefore, itis clear that
man differs less from the chimpanzee or the orang than these
do even from the monkeys, and that the difference between
the brain of the chimpanzee and of man is almost insignifi-
cant, when compared with that between the chimpanzee
brain and that of a Lemur.”
In the paper to which I have referred, Prof. 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 sec-
ondly, goes on to assert that, ‘‘If we successively 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, Cynocephalus,
Cercopithecus, Macacus, Cebus, Cailithrix, 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, first, that whether this assertion be
true or false, it has nothing whatever to do with the proposi-
tion 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 Prof. Bischoff had taken
™ “‘Mau’s Place in Nature,’’ p. 102.
268 THE DESCENT OF MAN
the trouble to refer to p. 96 of the work he criticises, in fact,
he would have found the following passage: ‘‘And it isa
remarkable circumstance that though, so far as our present
knowledge extends, there is one true structural break in the
series of forms of Simian brains, this biatus does not lie be-
tween 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 cerebel-
lum 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 con-
trary, has its 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 dis-
covery of the relatively small development of the posterior
lobes in the Siamang and in the Howling monkey. Not-
withstanding 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 Prof.
Bischoff most unaccountably does, we write the series of ani-
mals he has chosen to mention as follows: Homo, Pithecus,
Troglodytes, Hylobates, Semnopithecus, Cynocephalus, Cerco-
ithecus, Macacus, Cebus, Callithrix, Hapale, Lemur, Stenops,
f ventate to reaffirm that the great break in this series lies
between Hapale and Lemur, and that this break is consider-
ably greater than that between any other two terms of that
series. Prof. Bischoff ignores the fact that long before he
wrote, Gratiolet had suggested the separation cf the Lemurs
from the other Primates on the very ground of the difference
in their cerebral characters; and that Prof. Flower had made
the following observations in the course of his description of
the brain of the Javan Loris:”
‘‘And it is especially remarkable that, in the develop-
ment of the posterior lobes, there is no approximation to
the Lemurine, short-hemisphered brain, in those monkeys
which are commonly supposed to approach this family in
% ‘*Trangactions of the Zoological Society,’’ vol. v., 1862,
STRUCTURE OF THE BRAIN 269
other respects; viz., the lower members of 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 investi-
gators, during the past ten years, fully justify the statement
which [ made in 1868. 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
they 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 agreement in the
development of the brain in men and apes.
Gratiolet originated the statement that there is a funda-
mental 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 hemispheres, while,
in the human foetus, the sulci first become visible on the
frontal lobes.”
This general statement is based upon two observations,
the one of a Gibbon almost ready to Es born, in which the
osterior gyri were ‘‘well developed,’’ while those of the
rontal lobes were ‘‘hardly indicated’’"” (1. ¢., p. 39), and
%8 ‘Chez tous les singes, les plis postérieurs se développent les premiers;
les plis antérieurs se développent plus tard, aussi la vertébre occipitale et la
pariétale sont-elles relativement trés-grandes chez le foetus. L’Homme pré-
sente une exception remarquable quant & Vépeque de V’apparition des plis
frontaux, gui sont Jes premiers indiqués; mais le développement général du lobe
frontal, envisagé seulement par rapport 4 son volume, suit les mémes lois que
dans les singes.*’ Gratiolet, ‘‘Mémoire sur les plis cérébraux de 1’Homme
et des Primates,’’ p. 39, tab. iv. fig. 3.
7 Gratiolet’s words are (I. ¢., p. 39): ‘‘Dans Je foetus dont il s’agit les plis
eérébraux postérieurs sont bien développés, tandis que les plis du lobe frontal
sont 4 peine indiqués.’’ The figure, however (Pl. iv. fig. 8), shows the fissure
of Rolando, and one of the frontal sulci, plainly enough. Nevertheless,
M. Alix, in his “‘Notice sur les travaux anthropologiques de Gratiolet’?
(“Mém. de la Société d’Anthropologie de Paris,”? 1868, p. 32), writes thus:
‘Gratiolet a eu entre Jes mains le cerveau @’un foetus de Gibbon, singe éminem-
ment supérieur, et tellement rapproché de orang, que des naturalistes trés
compétents l’ont rangé parmi les anthropoides. M. Huxley, par exemple,
n’hésite pas sur ce point. Eh bien, c’est sur le cerveau d’un foetus de Gibbon
que Gratiolet a vu les cérconvolutions du lobe temporo-sphénoidal déja développées
dors-qu'il nexiste pas encore de plis sur le lobe frontal. Il était donc bien
autorisé a dire que, chez ’homme les circonvolutions apparaissent d’e en @,
tandis que chez les singes elles se développent d’« en a.”?
270 THE DESCENT OF MAN
the other of a human foetus at the 22d or 23d week of utero-
gestation, in which Gratiolet notes that the insula was un-
covered, but that, nevertheless, ‘‘des incisures sément le
lobe antérieur; une scissure peu profonde indique la sépa-
ration du_lobe occipital, ee uit d’ailleurs dés cette
époque. Le reste de la surface cérébrale est encore abso-
lument lisse.”’
Three views of this brain are given in Plate IL., Figs.
1, 2, 3 of the work cited, showing the upper, lateral, and
inferior views of the hemispheres, 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 (antero-
temporal) on the posterior half of the face of the hemi-
sphere 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: ‘‘1l y a done entre ces cer-
veaux [those of a Callithrix and of a Gibbon] et celui du
foetus humain une différence fondamentale. Chez celui-ci,
longtemps avant que les plis temporaux apparaissent, les plis
frontaux essayent 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,” and
more particularly by Ecker,” 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 utero-gestation. In this
and in the fourth month the cerebral hemispheres are smooth
and rounded (with the exception of the Sylvian depression),
and they project backward far beyond the cerebellum. |
2. The sulci, properly so called, begin to ihe 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 appear-
ance is subject to considerable individual variation. In no
case, however, are either the frontal or the temporal sulci
the earliest.
78 “‘Yeber die typische Anordnung der Furchen und Windungen auf den
Grosshirn-Hemispharen des Menschen und der Affen.”” ‘‘Archiv fir Anthro-
pologie,’? iii., 1868. a
” “Yur Entwickelungs Geschichte der Furchen und Windungen der
Grosshirn-Hemispharen im Foetus des Menschen.”” “‘Archiv fir Anthropolo-
gie,”’ iii., 1868.
STRUCTURE OF THE BRAIN 271
The first which appears, in fact, lies on the inner face of
the hemisphere (whence doubtless Gratiolet, who does not
seem to have examined that face in his foetus, overlooked
it), and is either the internal perpendicular (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.
8. At the latter part of this period, another sulcus, the
‘‘posterio-parietal,’’ or ‘‘Fissure of Rolando,” 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 ea at the period described and
figured by Hcker (1. c., pp. 212-18, Taf. II. Figs. 1, 2, 8, 4),
-the antero-temporal sulcus (scissure paralléle), so character-
istic of the ape’s brain, is as well if not better developed
than the fissure of Rolando, and is much more marked than
the proper frontal sulci.
aking 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 harmony with the general doctrine
of evolution,’ and with the view that man has been evolved
from some ape-like form; though there 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 their 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 characters of a fish,
and, if it went no further, would have to be grouped among
fishes. But it is equally true that the tadpole is very differ-
ent 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 lobes, and with
no sulci but the Sylvian and the calcarine, present the char-
272 THE DESCENT OF MAN
acteristics found only in the group of the Arctopithecine Pri-
mates. 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 foetal Cebus Apella, in addition
to the Sylvian fissure and the deep calcarine fissure, only a
very shallow antero-temporal fissure (scissure paralléie 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 ante-
rior half of the exterior of the cerebral hemispheres, or none
at all, undoubtedly, so far as it goes, affords fair evidence
in favor of Gratiolet’s hypothesis, that the posterior sulci
appear before the anterior, in the brains of the Platyrhint.
But it by no means follows that the rule which may hold
good for the Platyrhint extends to the Catarrhini. We
have no information whatever respecting the development
of the brain in the Cynomorpha; and, as regards the An-
thropomorpha, 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 show 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, ‘‘I] est
dangereux dans les sciences de conclure trop vite.’’ I fear
he must have forgotten this sound maxim by the time he
had reached the discussion of the differences between men
and apes, in the body of his work. No doubt, the excellent
author of one of the most remarkable contributions to the
just understanding of the mammalian brain which has ever
een made, would have been the first to admit the insuffi-
ciency 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 foun-
dation, as arguments in favor of obscurantism.”
But it is important to remark that, whether Gratiolet was
80 For example, M. Abbé Lecomte in his terrible pamphlet, ‘“‘Le Darwinisme
et lorigine de 1’Homme,”’’ 1873.
STRUCTURE OF THE BRAIN 2738
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 modi-
fication of the same form as that from which the other Pri-
mates have sprung.
—
PART TWO
SEXUAL SELECTION
CHAPTER VIII
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 selec-
tion—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 ore sex and the young are
not modified through sexual selection—Supplement on the proportional
numbers of the two sexes throughout the animal kingdom—The pro-
portion of the sexes in relation to natural selection
ITH 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 characters, which are not di-
rectly connectedswith the act of reproduction; 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 hold-
ing her securely. These latter organs, of infinitely diversi-
fied 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 append-
ages at the apex of the abdomen. in male insects. Unless
indeed we confine the term ‘‘primary’’ to the reproductive
(274)
SEXUAL SELECTION 275
glands, it is scarcely possible to decide which ought to be
called primary and which secondary.
The female often differs from the male in having organs
for the nourishment or protection of her young, such as the
mammary glands of mammals, and the abdominal sacs 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 col-
lecting and carrying pollen, and their ovipositor is modified
into a sting for the defence of the larve 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 is with 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 gaudy coloring 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 ani-
mals 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 (Culicids and Tabanidz)
are blood-suckers, while the males, living on flowers, have
mouths destitute of mandibles.’ The males of certain moths
and of some crustaceans (e.g., Tanais) have imperfect, closed
mouths, and cannot feed. The complemental males of cer-
tain Cirripeds 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-
1 Westwood, *‘Modern Class. of Insects,’’ vol. ii., 1840, p. 541. For the
gtatement about Tanais, mentioned below, I am indebted to Frits Miller.
276 THE DESCENT OF MAN
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 (Curculionids) there is a great difference
between the male and female in the length of the rostrum
or snout;? 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 won-
derfully great, and we hear from Dr. Buller*® that the male
uses his strong beak in chiselling the larve of insects out
of decayed wood, while 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, differ-
ences 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 he 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.
K We are, however, here concerned only with sexual selec-
tion. This depends on the advantage which certain_indi-
viduals have over others of the same sex and species solely
in respect of reproductionX When, as in the cases above
mentioned, the two sexes differ in structure in relation to
different habits of life, they have no doubt been modified
through natural selection, and by inheritance limited to one
2 See Kirby and Spence’s work, “‘Introduction to Entomology,’’ volume iif,,
1826, page 309.
3 “Birds of New Zealand,’’ 1872, p. 66
SEXUAL SELECTION 277
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 gen- -
erated or nourished their offspring best would leave, ceteris
paribus, the greatest number to inherit their superiority,
while 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; but if these organs are necessary for
the other purposes of life, as 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 antennze
modified in an extraordinary manner for the prehension of
the female; hence we may suspect that it is because 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 iow 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 like a rasp, and with this they coil round and
permanently hold the females.‘
When the two sexes follow exactly the same habits of
life, and the male has the sensory or locomotive organs more
4M. Perrier advances this case (‘‘Revue Scientifique,’? Feb. 1, 1873,
p. 865) as one fatal to the belief in sexual selection, inasmuch as he supposes
that I attribute ell the differences between the sexes to sexual selection. This
distinguished naturalist, therefore, like so many other Frenchmen, has not
taken the trouble to understand even the first principles of sexual selection.
An English naturalist insists that the claspers of certain male animals could
not have been developed through the choice of the female! Had I not met
with this remark, I should not have thought it possible for any one to have
read this chapter and to have imagined that I maintain that the choice of the
female had anything to do with the development of the prehensile organs in
the male.
278 THE DESCENT OF MAN
highly developed than those of the female, it may be that
the perfection of these is indispensable to the male for find-
ing 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 exist-
ence, 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 Selec-
tion. 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 indi-
viduals 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 con-
trivances for producing vocal or instrumental music—and
their glands for emitting odors, most of these latter struct-
ures serving only to allure or excite the female. It is clear
that these characters are the result of sexual and not of
SEXUAL SELECTION 279
ordinary selection, since unarmed, unornamented, or unat-
tractive 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 of 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 performing strange antics before an assembled
body of females, we cannot doubt that, though led by in-
stinct, 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
cock-pit, so it appears that the strongest and most vigorous
males, or those provided with the best weapons, have pre-
vailed under nature, and have led to the improvement of
the natural breed or species. A slight degree of variability
leading to some advantage, however slight, in reiterated
deadly contests would suffice for the work of sexual selec-
tion; and it is certain that secondary sexual characters are
eminently variable. Just as man can give beauty, accord-
ing 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 ap-
pears 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 pow-
ers of discrimination and taste on the part of the female
which will at first appear extremely improbable; but, by the
facts to be adduced hereafter, I hope to be able to show that
the females actually have these powers. When, however,
280 THE DESCENT OF MAN
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 comparison 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 man-
ner in which sexual selection acts is somewhat uncertain.
Nevertheless, 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 among 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 the opportunity of
selecting one out of several males, on the supposition that
their mental capacity suffices for the exertion of a choice.
In many cases special circumstances tend to make the strug-
gle 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 nightingale 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 Ray’s wagtail (Budytes
fait) before he saw a single female. Mr. Gould has ascer-
tained, 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
SEXUAL SELECTION 281
of the United States.° 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
ean 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 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, with-
out at the same time interfering with the period of the pro-
duction 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 under-
standing 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 superi-
ority 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,
5 J, A, Allen, on the ‘‘Mammals and Winter Birds of Florida,’’ Bull. Comp.
Zoology, Harvard College, p. 268.
6 Even with those plants in which the sexes are separate, the male flowers
are generally mature before the female. As first shown by C. K. Sprengel,
many hermaphrodite plants are dichogamous; that is, their male and female
organs are not ready at the same time, so that they cannot be self-fertilized,
Now in such flowers the pollen i is in general matured before the stigma, though
there are exceptional cases in which the female organs are beforehand.
282 THE. DESCENT OF MAN
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 even 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. There 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.” The males, as we have seen, are generally
ready to breed before the 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, because they are
the first to breed. Such vigorous pairs would surely rear
1 Here is excellent evidence on the character of the offspring from an ex-
perienced ornithologist. Mr. J. A. Allen, in speaking (‘‘Mammals and Winter
Birds of E. Florida,”’ p. 229) of the later broods, after the accidental destruction
of the first, says that these ‘‘are found to be smaller and paler-colored than
those hatched earlier in the season. In cases where several broods are reared
each year, as a general rule the birds of the earlier broods seem in all respects
the most perfect and vigorous.”
8 Hermann Miller has come to this same conclusion with respect to those
female bees which are the first to emerge from the pupa each year. See his
SEXUAL SELECTION _ 288
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 proba-
ble that they would at the same time prefer the more vig-
orous 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
attractive. Both sexes, therefore, of such early pairs would,
as above explained, have an advantage over others in rear-
ing 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 select-
ing 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 advantage in rearing offspring, more especially if
remarkable essay, “‘Anwendung den Darwin’schen Lehre auf Bienen,”’ ‘*Verh,
a, V. Jabrg.,”? xxix. p. 45.
® With respect to poultry, I have received information, hereafter to be
giver, to this effect. Even with birds, such as pigeons, which pair for life,
the female, as I hear from Mr. Jenner Weir, will desert her mate if he is
injured or grows weak.
284 THE DESCENT OF MAN
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 young. The same princi-
ples would apply if each sex preferred and selected certain
individuals of the opposite-sex; supposing that 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 considerably more numerous than the females. Hence
Iwas 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 ab-
stract of the results, retaining the details for a supplement-
ary discussion, so as not to interfere with the course of my
argument. Domesticated animals alone afford the means of
ascertaining the proportional numbers at birth; but no rec-
ords have been specially kept for this purpose. By indirect
means, however, I have collected a considerable body of sta-
tistics, 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 inequality is greater than with
any other animal, for out of 6,878 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 condi-
tions as under domestication; for slight and unknown dif- —
ferences 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
SEXUAL SELECTION 285
several years in the proportion of between 90 and 99 to
100 female children.
For our present purpose we are concerned with the pro-
portion 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 until
they become greatly emaciated. They must also be often
exposed to various dangers, while 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 fe-
males of some birds appear to die earlier than the males;
they are also liable to be destroyed on their nests, or while
in charge of their young. With insects the female larva
are often larger than those of the males, and would conse-
quently be more likely to be devoured. In some cases the
mature females are less active and less rapid in their move-
ments 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. Neverthe-
less, 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
luring 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
25.8. But had larger numbers been tabulated throughout
an area more extensive than England, these fluctuations
286 THE DESCENT OF MAN
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 shown in the supplement, the proportions
seem to fluctuate either during different seasons or in differ-
ent 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 off-
spring, 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 attractive males previously produced would still have
at least as good 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 are polygamous, but with
animals belonging to the lower classes I 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
favorable to the action of sexual selection. Nevertheless,
many animals which are strictly monogamous, especially
birds, display strongly marked secondary sexual charac-
ters; while some few animals which are polygamous do not
have such characters.
We will first briefly run through the mammals, and then
turn to birds. The gorilla seems to be polygamous, and the
SEXUAL SELECTION i 287
male differs considerably from the female; so it is with some
baboons, which live in herds containing twice as many adult
females as males. In South America the Mycetes caraya
presents well-marked sexual differences, in color, 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.”
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 sex-
ual 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 ante-
lopes of South Africa, says that in herds of about a dozen
there was rarely more than one mature male. The Asiatic
Antilope saiga appears to be the most inordinate polygamist
in the world; for Pallas’! states that the male drives away
all rivals, and collecust+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 West-
ern States of North 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 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
10 On the Gorilla, Savage and Wyman, ‘‘Boston Journal of Nat. Hist.,”’
vol. v., 1845-47, p. 423. On Cynocephalus, Brehm, ‘‘Ilust. Thierleben,”
B. i., 1864, 3. 77. On Mycetes, mengger, ‘“‘Naturgesch.: Saugethiere von
Paraguay, °? 1830, s. 14, 20. Cebus, Brehm, ibid., s. 108.
11 Pallas, “Spicilegia Zoolog.,’? Fase. xii., 1777, p. 29. Sir Andrew Smith,
“Tllustrations of the Zoology of S. Africa,’’ 1849, pl. 29, on the Kobus. Owen,
in his ‘‘Anatomy of Vertebrates”? (vol. iii., 1868, p. 633) gives a table showing
incidentally which species of antelopes are gregarious.
288 THE DESCENT OF MAN
several females. Whether this holds good in Europe is
doubtful, but it is supported by some evidence. The adult
made 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.’?_ 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 Rodents being polygamous, ex-
cepting that, among the Rodents, the common rat, according
to some rat-catchers, lives with several females. Neverthe-
less the two sexes of some sloths (Hdentata) differ in the
character and color of certain patches of hair on their shoul-
ders.**° And many kinds of bats (Cheiroptera) present well-
marked sexual differences, chieiti@@™™®ihe males possessing
odoriferous glands and pouches, and by their being of a
lighter color."* In the great order of Rodents, 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 among all the terres-
trial 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,
12 Dr. Campbell, in ‘‘Proc. Zoolog. Soc.,’? 1869, p. 138. See also an
interesting paper, by Lieut. Johnstone, in ‘‘Proc, Asiatic Soc. of Bengal,”
May, 1868.
13 Dr, Gray, in ‘‘Annals and Mag. of Nat. Hist.,’’ 1871, p. 302.
14 See Dr. Dobson’s excellent paper, in ‘‘Proc, Zoolog. Soc.,’’ 1873, p. 241.
SEXUAL SELECTION 289
and they are eminently polygamous. Thus, according to
Péron, 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 greater number of females. It is an interesting fact, as Dr.
Gill remarks,'* that in the monogamous species, ‘‘or those
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.’’
Among 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 bull-finch, which is said to
pair for life. I am informed by Mr. Wallace that the like
is true of the Chatterers or Cotingide of South America,
and of many other birds. In several groups I have not been
able to discover whether the species are polygamous or mo-
nogamous. Lesson says that birds-of-paradise, so remark-
able for their sexual differences, are polygamous, but Mr.
Wallace doubts whether he had sufficient evidence. Mr. Sal-
vin 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.'* 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 Gallinacez exhibit almost as strongly marked sexual
differences as birds-of-paradise or humming-birds, and many
18 The Eared Seals, ‘‘ American Naturalist,’’ vol. iv., Jan. 1871.
16 “‘The Ibis,’’ vol. iii., 1861, p. 133, on the Progne Widow-bird. See also
‘on the Vidua awillaris, ibid., vol. ii., 1860, p. 211. On the polygamy of the
Capercailzie and Great Bustard, see L. Lloyd, ‘‘Game Birds of Sweden,’’ 1867,
pp. 19 and 182. Montagu and Selby speak of the Black Grouse as polygamous,
and of the Red Grouse as monogamous.
Descent—Vou. I.—13
290 THE DESCENT OF MAN
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 monogamous guinea-fowl or partridge! Many simi-
lar cases could be given, as in the grouse tribe, in which the
males of the polygamous capercailzie and black-cock differ
greatly from the females; while the sexes of the monoga-
mous red grouse and ptarmigan differ very little. In the
Cursores, except among the bustards, few species offer
strongly marked sexual differences, and the great bustard
(Otis tarda) is said to be polygamous. With the Gralia-
tores, extremely few species differ sexually, but the ruff
(Machetes pugnax) affords a marked exception, and this
species is believed by Montagu to be a polygamist. Hence
it appears that among birds there often exists a close rela-
tion 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 Gal-
linacews) was polygamous, and I was struck by his an-
swering, ‘‘I do not know, but should think so from his
splendid colors.”’
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 polyga-
mous. The Rev. W. D. Fox informs me that out of some
half-tamed wild-ducks, on a large pond in his neighborhood,
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 mo-
nogamous; but Mr. Fox finds that his birds succeed best
when he keeps one cock to two or three hens. Oanary-
birds pair in a state of nature, but the breeders in England
successfully put one male to four or five females. J have
noticed these cases, as rendering it probable that wild mo-,
nogamous species might readily become either temporarily
or permanently polygamous.
SEXUAL SELECTION 291
Too little is known of the habits of reptiles and fishes
to enable us to speak of their marriage arrangements. The
stickleback (Gasterosteus), however, is said to be a polyga-
mist;” 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 shown 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 num-
ber 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 advantage
thus gained by the more vigorous pairs in rearing a larger
number of offspring has apparently sufficed to render sexual
selection efficient. Buta large numerical preponderance 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 afterward from the greater
destruction 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 fe-
male retains a closer resemblance to the young of her own
species, and to other adult members of the same group.
The cause of this seems to lie in the males of almost all
x a ern re “River Gardens,’’ 1854.
292 THE DESCENT OF MAN
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 su-
periority to their male offspring. Why both sexes do not
thus acquire the characters of their fathers will be consid-
ered hereafter. 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 re-
marks,’® ‘‘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 fe-
males. 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 shows
that the male is the more active member in the courtship
of the sexes.’
The female, on the other hand, with the rarest ex-
ceptions, is less eager than the male. As the illustrious
Hunter” long ago observed, she generally ‘‘requires to be
courted’’; she is coy, and may often be seen endeavoring
18 Kirby and Spence, ‘‘Introduction to Entomology,”’ vol. iii., 1826, p. 342.
19 One parasitic Hymenopterous insect (Westwood, ‘‘Modern Class. of
Tnsects,’’ vol. ii. p. 160) forms an exception to the rule, as the male has rudi-
mentary wings, and never quits the cell in which it is born, while the female
has well-developed wings. Audouin believes that the females of this species
are impregnated by the males which are born in the same cells with them; but
it is much more probable that the females visit other cells, so that close inter-
breeding is thus avoided. We shall hereafter meet in various classes with
a few exceptional cases in which the female, instead of the male, is the seeker
and wooer,
20 “‘Hssays and Observations,’’ edited by Owen, vol. 1., 1861, p. 194,
SEXUAL SELECTION 293
for a long time to escape from the male. Every observer
of the habits of animals will be able to call to mind in-
stances 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 pref-
erence 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 inquire 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 ac-
tive part in courtship. 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 fertilization have to be nourished for a time;
hence the pollen is necessarily brought to the female organs
—hbeing placed on the stigma, by means of insects or the
wind, or by the spontaneous movements of the stamens; and
in the Alge, etc., by the locomotive power of the anthero-
zooids. With lowly organized 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 de-
tached before fertilization, and did not require subsequent
nourishment or protection, there would yet be greater diffi-
culty 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
respect, analogous with plants.** The males of affixed and
aquatic animals having been led to emit their fertilizing ele-
ment in this way, it is natural that any of their descendants,
21 Prof. Sachs (‘‘Lehrbuch der Botanik,’’ 1870, s, 633), in speaking of the
male and female reproductive cells, remarks, ‘‘Verhalt sich die eine bei der
Vereinig'ing activ, . . . die andere erscheint bei der Vereinigung passiv.”’
294 THE DESCENT OF MAN
which rose in the scale and became locomotive, should re-
tain the same habit; and they would approach the female
as closely as possible, in order not to risk the loss of the
fertilizing element in a long passage of it through the water.
With some few of the lower 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
acquirement 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.” Good evidence also in favor of this conclusion
can be produced by a comparison of the two sexes in man-
kind. During the Novara Expedition 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,” who has carefully attended to the variation
of the muscles in man, puts in italics the conclusion that
2% “*Vortrige iiber Viehzucht,’’ 1872, p. 63.
28 “Reise der Novara: Anthropolog. Theil,’? 1867, s, 216-269. The
results were calculated by Dr. Weisbach from measurements made by Drs.
K. Scherzer and Schwarz. On the greater variability of the males of domesti-
cated animals, see my ‘‘Variation of Animals and Plants under Domestication,’’
vol. ii., 1868, p. 75.
34 ‘Proceedings Royal Soc.,”’ vol. xvi., July 1868, pp. 519 and 524.
SEXUAL SELECTION ~ 295
“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.’’ Prof. Macalister likewise remarks” that
variations in the muscles ‘‘are probably more common in
males than females.’’ Certain muscles which are not nor-
mally present in mankind are also more frequently devel-
oped in the male than in the female sex, although exceptions
to this rule are said to occur. Dr. Burt Wilder’ has tabu-
lated the cases of 152 individuals with supernumerary digits,
of which 86 were males, and 89, or less than half, females,
the remaining 27 being of unknown sex. It should not,
‘however, be overlooked that women would more frequently
endeavor 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.” Lastly, the tem-
perature is more variable in man than in woman.”
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 independently of selection
the two sexes, from differing constitutionally, 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 exert-
% “*Proc, Royal Irish Academy,’’ vol. x., 1868, p. 123.
%6 **Massachusetts Medical Soc.,’’ vol. ii. No. 3, 1868, p. 9.
21 “ Archiv fir Path, Anat. und Phys.,’’ 1871, p. 488.
98 The conclusions recently arrived at by Dr. J. Stockton-Hough, on the
temperature of man, are given in the ‘‘Pop. Sciente Review,’’ Jan. 1, 1874,
p. 97.
296 THE DESCENT OF MAN
ing his voice, pouring out odoriferous secretions, etc.; and
this expenditure is generally concentrated within a short
period. The great vigor of the male during the season
of love seems often to intensify his colors, independently of
any marked difference from the female.” 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.”
On the whole, the expenditure of matter and force by the
two sexes is probably nearly equal, though effected ia 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. Nevertheless, they may
become permanent if the exciting cause acts permanently;
and, in accordance with a frequent form of inheritance, 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 shows that with a large number of birds
inhabiting the northern and southern United States, the
specimens from the south are darker-colored than those
from the north; and this seems to be the direct result of the
difference in temperature, light, etce., between the two re-
gions. Now, in some few cases, the two sexes of the same
species appear to have been differently affected; in the
29 Prof. Mantegazza is inclined to believe (‘‘Lettera a Carlo Darwin,”
‘Archivio per P Anthropologia,’’ 1871, p. 306) that the bright colors common
in so many male animals are due to the presence and retention by them of the
spermatic fluid: but this can hardly be the case; for many male birds, for
instance young pheasants, become brightly colored in the autumn of their
first year.
80 For mankind, see Dr. J. Stockton-Hough, whose conclusions are given in
the ‘‘Pop. Science Review,’’ 1874, p. 97. See Girard’s observations on the
Lepidoptera, as given in the ‘‘Zoological Record,” 1869, p. 347,
SEXUAL SELECTION 297
Ageleus pheniceus the males have had their colors greatly
intensified in the south; whereas with Cardinalis virginianus
it is the females which have been thus affected; with
Quiscalus major the females have been rendered extremely
variable in tint, while the males remain nearly uniform.*
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 colors, greater size, strength, or pugnacity.
With birds there has sometimes been a complete transpo-
sition 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 colored 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 attrac-
tive 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 beautiful differed; but this is a supposition too improb-
able to be worth considering in the case of any animal, ex-
cepting 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 attrib-
ute to the agency of sexual selection. In such cases it may
be suggested with more plausibility, that there has been a
double or mutual process of sexual selection; the more
vigorous and precocious females selecting the more attrac-
tive and vigorous males, the latter rejecting all except the
more attractive females. But from what we know of the
31 **Mammals and Birds of E. Florida,’’ pp. 234, 280, 295.
298 THE DESCENT OF MAN
habits of animals, this view is hardly probable, for the male
is generally eager to pair with any female. It is more prob-
able that the ornaments common to both sexes were acquired
by one sex, generally the male, and then transmitted to the
offspring of both sexes. If, indeed, during a lengthened
period the males of any species were greatly to exceed the
females in number, 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 colored nor provided with special
ornaments, and yet the members of both sexes or of one
alone have probably acquired simple colors, 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 colors 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 off-
spring were left by the more successful males to inherit
their superiority, than by the less successful: and this, as
previously shown, depends on many complex contingencies.
Sexual selection acts in a less rigorous manner than natu-
- ral 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 polygamous, obtains fewer
females; so that they leave fewer, less vigorous, or no off-
SEXUAL SELECTION 299
spring. 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 pur-
poses; 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 advanta-
geous modification; so that as long as the proper variations
arise the work of sexual selection will go on. This circum-
stance may partly account for the frequent and extraordi-
nary amount of variability presented by secondary sexual
characters. Nevertheless, natural selection will determine ©
that such characters shall not be acquired by the victorious
males, if they would be highly injurious, either by expend-
ing 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 favored males
derive from conquering 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 adapta-
tion 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 OF 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 ‘‘inheri-
tance’’—the transmission and the development of characters;
800 THE DESCENT OF MAN
but, as these generally go together, the distinction is often
overlooked. We see this distinction in those characters which
are transmitted through the early years of life, but are de-
veloped only at maturity or during old age. We see the
same distinction more clearly with secondary sexual charac-
ters, 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 transmits the char-
acters proper to its own male and female sex to the hybrid
offspring of either sex. "The same fact is likewise manifest
when characters proper to the male are occasionally devel-
oped 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 pug-
nacity of the cock. Conversely, the same thing is evident,
more or less plainly, with castrated males. Again, inde-
pendently 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 simply developed in
the female; for in every breed each detail in the structure
of the spur is transmitted through the female to her male
offspring. Many eases 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 development of characters in the female, and of
transference to the male, is less frequent; it will therefore
be well to give one striking instance. With bees the pollen-
collecting apparatus is used by the female alone for gather-
ing pollen for the larve, 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.* As not a single other Hymenopterous insect,
32 M. Miiller, ‘“‘Anwendung der Darwin’schen Lehre,”’ ete., ‘Verh. d. n.
V. Jabrg.”? xxix. p. 42.
SEXUAL SELECTION 801
not even the wasp, which is closely allied to the bee, is pro-
vided 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 sus-
pect 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
favorable 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 gem-
mules 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 ten-
dency 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 reappear in the offspring at the same advanced
age. When deviations from this rule occur, the transmitted
characters much oftener appear before than after the corre-
sponding age. As I have dwelt on this subject sufficiently
in another work,* I will here merely give two or three in-
stances, 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
33 ‘The Variation of Animals and Plants under Domestication,’’ vol. ii,
1868, p. 75. In the last chapter but one, the provisional hypothesis of
pangenesis, above alluded to, is fully explained.
802 THE DESCENT.OF MAN
the adults differ greatly from one another, as well as from
their common parent-form, the Gallus bankiva; 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, while 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 plumage ‘‘they are beautifully pencilled,”’
that is, each feather is transversely marked by numerous
dark bars; but in their second plumage the feathers all be-
come spangled or tipped with a dark, round spot.** Hence
in this breed variations have occurred at, and been trans-
mitted 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 colors until they have moulted two, three, or
four times; and these modifications of plumage are regularly
transmitted.
Inheritance at Corresponding Seasons of the Year.—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 colors and other decorations
during the breeding-season alone. Pallas states,** that in
Siberia domestic cattle and horses become lighter-colored
during the winter; and I have myself observed and heard
24 These facts are given on the high authority of a great breeder, Mr.
Teebay; see Tegetmeier’s ‘‘Poultry Book,’’ 1868, p. 158. On the characters
of chickens of different breeds, and on the breeds of the pigeon, alluded to in
the following paragraph, see ‘‘Variation of Animals,’’ etc., vol. i. pp. 160, 249;
vol. ii. p. 77. :
35 ‘Nove species Quadrupedum e Glirium ordine,’? 1778, p. 7. On the
transmission of color by the horse, see ‘‘Variation of Animals, etc., under
Domestication,’’ vol. i. p. 51. Also vol. ii. p. 71, for a general discussion on
‘Inheritance as limited by Sex.”’
SEXUAL SELECTION 303
of similar strongly marked changes of color, that is, from
brownish cream-color or reddish-brown to a perfect white,
in several ponies in England. Although I do not know
that this tendency to change the color of the coat during
different seasons is transmitted, yet it probably is so, as
all shades of color are 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 inheri-
tance, at least with those animals which do not present
strongly marked sexual differences, and indeed with many
of these. But characters are somewhat commonly trans-
ferred 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 in-
stances 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, ac-
quired under domestication, are regularly transmitted to the
same sex. Asarule, it is the females alone in cats which
are tortoise-shell, the corresponding color 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, while the females differ considerably in color. The
sexes of the pigeon in the parent-species do not differ in
any external character; nevertheless, in certain domesticated
breeds the male is colored differently from the female.”
36 Dr, Chapuis, ‘Le Pigeon Voyageur Belge,’’ 1865, p. 87. Boitard et
Corbié, ‘‘Les Pigeons de Voliére,’’ etc., 1824, p. 173. See, also, on similar
differences in certain breeds at Modena, ‘‘Le variazioni dei Colombi domestici,”’
del Paolo Bonizzi, 1873.
804 THE DESCENT OF MAN
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 opposition to, the wish of the breeder.
Most of our domestic races have been formed by the ac-
cumulation 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 dis-
similarity and complete similarity. Instances have already
been given with the breeds of the fowl and pigeon, and
under nature analogous cases are common. With animals
under domestication, but whether in nature I will not ven-
ture to say, one sex may lose characters proper to it, and
may thus come somewhat to resemble the 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 while
young; or, aS in certain Polish sub-breeds, in which the
females, as there is reason to believe, originally acquired
a crest, and subsequently transferred it to the males. All
these cases are intelligible 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 in-
stance, a breeder observed that some of his pigeons (of
SEXUAL SELECTION 305
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, while the females remained un-
changed? 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 color, as indeed has been
effected with a Belgian breed, in which the males alone are
streaked with black. Ina similar manner, if any variation
appeared in a female pigeon, which was from the first sex-
ually limited in its development to the females, it would be
easy to make a breed with the females alone thus charac-
terized; but if the variation was not thus originally limited,
the process would be extremely difficult, perhaps impossible.”
On the Relation between the Period of Development of a
Character and its Transmission to One Sex or to Both Seaes.—.
Why certain characters should be inherited by both sexes,
and other characters 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 striz, though transmitted
through the female, should be developed in the male alone,
while every other character is equally transferred to both
sexes. Why, again, with cats, the tortoise-shell color
37 Since the publication of the first edition of this work, it has been highly
satisfactory to me to find the following remarks (‘‘The Field,’’ Sept. 1872) from
go experienced a breeder as Mr. Tegetmeier. After describing some curious
cases in pigeons, of the transmission of color by one sex alone, and the forma-
tion of a sub-breed with this character, he says: ‘‘It is a singular circumstance
that Mr. Darwin should have suggested the possibility of modifying the sexual
colors of birds by a course of artificial selection. When he did so, he was in
ignorance of these facts that I have related; but it is remarkable how very
closely he suggested the right method of procedure.”’
806 THE DESCENT OF MAN
should, with rare exceptions, be developed in the female
alone. The very same character, such as deficient or super-
numerary digits, color-blindness, etc., may with mankind
be 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.** Although we are thus ignorant, the two follow-
ing rules seem often to hold good—that variations which
first appear in either sex ata late period of life tend to be
developed in the same sex alone, while 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 dis-
cussed this subject, and as it has an important bearing on
sexual selection, I must here enter into lengthy and some-
what 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 side
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 gen-
erality of this fact is quite remarkable: it holds good with
almost all mammals, birds, amphibians, and fishes; also
with many crustaceans, spiders, and some few insects, such
as certain orthoptera and libellule. In all these cases the
38 References are given in my ‘‘Variation of Animals under Domestication,”
vol. ii. p. 72.
SEXUAL SELECTION 307
variations, through the accumulation of which the male
acquired his proper masculine characters, must have oc-
curred at a somewhat late period of life; otherwise the
young males would have been similarly characterized; 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 ac-
quired their present characters probably occurred, accord-
ing to our rule, during youth. But there is here room for
doubt, for characters are sometimes transferred to the off-
spring at an earlier age than that at which they first ap-
peared in the parents, so that the parents may have varied
when adult, and have transferred their characters to their
offspring while 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; neverthe-
less, 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
variations 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 there 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 obvi-
ously 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.
308 THE DESCENT OF MAN
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 other species the horns ought to —
appear later in life, which would lead to their development
in that sex alone in which they first appeared in the pro-
genitor of the whole Family. Now in seven species, belong:
ing 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. But with
the reindeer the case is widely different; for, as I hear from
Professor Nilsson, who kindly made special inquiries 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 pro-
vided with horns, while 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
89 Tt am much obliged to Mr. Cupples for having made inquiries for me in
regard to the Roebuck and Red Deer of Scotland from Mr. Robertson, the experi-
enced head forester to the Marquis of Breadalbane. In regard to Fallow-deer,
I have to thank Mr. Eyton and others for information. For the Cervus alces
of N. America, see ‘‘Land and Water,’’ 1868, pp. 221 and 254; and for the
C. Virginianus and strongyloceros of the same continent, see J. D, Caton, in
“Ottawa Acad. of Nat. Se.,”? 1868, p. 13. For Cervus EHidi of Pegu, see Lieut.
Beavan, ‘‘Proc. Zoolog. Soc.,’’ 1867, p. 762.
SEXUAL SELECTION 3809
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, considering
the size ultimately attained by them; while 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,” 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 we do know with respect to the
horns of deer, cattle, etc., those 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
afterward.*? 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 inquiry* that the horns are
developed later in life in this breed than in ordinary sheep
in which both sexes are horned. But with domesticated
4 Antilocapra Americana. I have to thank Dr. Canfield for information
with respect to the horns of the female: see also his paper in ‘Proc. Zoolog.
Soc.,”? 1866, p. 109. Also Owen, ‘‘Anatomy of Vertebrates,’’ val. iii. p. 627.
41 Thave been assured that the horns of the sheep in North Wales can
always be felt, and are sometimes even an inch in length, at birth. Youatt
says (‘‘Cattle,’? 1834, p. 277), that the prominence of the frontal bone in cattle
penetrates the cutis at birth, and that the horny matter is soon formed over it,
42 JT am greatly indebted to Prof. Victor Carus for having made inquiries for
me, from the highest authorities, with respect to the merino sheep of Saxony.
On the Guinea coast of Africa there is, however, a breed of sheep in which,
as with merinos, the rams alone bear horns; and Mr. Winwood Reade informs
mne that in one case observed by him a young ram, born on Feb. 10, first showed
horns on March 6, so that in this instance, in conformity with rule, the develop-
ment of the horns occurred at a later period of life than in Welsh sheep, in
which both sexes are horned. ;
310 THE DESCENT OF MAN
sheep the presence or absence of horns is not a firmiy 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
protuberances so common on the heads of birds,** 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 auritum), 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 ap-
pear 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 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.** 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
43 “‘TJeber die knéchernen Schadelhécker der Végel,’’ in the ‘‘Niederland-
ischen Archiv fiir Zoologie,’’ Band I. Heft 2, 1872.
44 In the common peacock (Pavo cristatus) the male alone possesses spurs,
while both sexes of the Java peacock (P. muticus) offer the unusual case. of
being furnished with spurs. Hence I fully expected that in the latter species
they would have been developed earlier in life than in the common peacock;
but M. Hegt of Amsterdam informs me that with young birds of the previous
year, of both species, compared on April 23, 1869, there was no difference in
the development of the spurs, The spurs, however, were as yet represented
merely by slight knobs or elevations. I presume that I should have been
informed if any difference in the rate of development had been observed
subsequently.
SEXUAL SELECTION 311
developed very early in life, long before the other orna-
ments, 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 smallér in the female, and it is developed early
in life, while the curled tail-feathers and other ornaments of
the male are developed later.** Between such extreme cases
of close sexual resemblance and wide dissimilarity as
those of the Crossoptilon and peacock, many intermediate
enes 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 colored scales,
for instance, in two species of butterflies, in one of which
the sexes differ in color, while 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 devel-
oped on the wings of the same species of butterfly, in which
certain colored marks are confined to one sex, while 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.
4 Tn some other species of the Duck family the speculum differs in a greater
degree in the two sexes; but I have not been able to discover whether its full
development occurs later in life in the males of such species than in the male
of the common duck, as ought to be the case according to our rule. With the
allied Mergus cucullatus we have, however, a case of this kind: the two sexes
differ conspicuously in general plumage, and to a considerable degree in the
speculum, which is pure white in the male and grayish white in the female.
Now the young males at first entirely resemble the females, and have a grayish
white speculum, which becomes pure white at an earlier age than that at
which the adult male acquires his other and more strongly marked sexual differ-
ences: see Audubon, ‘‘Ornithological Biography,”’ vol. iii., 1835, pp. 249-250.
312 THE DESCENT OF MAN
We have as yet considered the transference of characters,
relatively 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 supernumerary digits, and the absence of certain pha-
langes, must be determined at an early embryonic period—
the tendency to profuse bleeding is at least congenital, as is
probably color-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 transmitted 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 trans-
mitted 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 development of their horns, forehead, mane,
dewlap, tail, and hump on the shoulders; and these pecu-
liarities, 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 increased
size being transmitted to his male offspring alone. On the
SEXUAL SELECTION 313
other hand, the tortoise-shell color, 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 are streaked with black, and the streaks can be de-
tected even in the nestlings; but they become more con-
spicuous 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, conform-
ably 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, **
in which both sexes change their color 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 vari-
ous characters by one or both sexes seems generally deter-
mined by the period at which such characters are developed.
Thus in all the many breeds in which the adult male differs
greatly in color 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 colored in nearly the same manner as their
parents, and this renders it probable that their colors first
appeared early in life. We have instances of this fact in
48 “Das Ganze der Taubenzucht,’’ 1837, s. 21, 24. For the case of the
, streaked pigeons, see Dr. Chapuis, ‘‘Le pigeon voyageur Belge,’’ 1865, p. 87,
Descent—Vot. I.—14
314 THE DESCENT OF MAN
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 white 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 colored. 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
colored 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 Hamburgs, however, offer
a partial exception; for the two sexes, though not quite
alike, resemble each other more closely than do the sexes
of the aboriginal parent-species; yet they acquire their char-
acteristic plumage late in life, for the chickens are distinctly
pencilled. With respect to other characters besides color, 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 theadult female. In
the Game breeds pugnacity is developed at a wonderfully
early age, of which curious proofs could be given; and this
character is transmitted to both sexes, so that the hens, from
their extreme pugnacity, are now generally exhibited in
separate pens. With the Polish breeds the bony protuber-
ance 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;*
and in this breed the adults of both sexes are characterized
by a great bony protuberance and an immense crest.
Finally, from what we have now seen of the relation
4" For full particulars and references on all these points respecting the
several breeds of the Fowl see ‘‘Variation of Animals and Plants under Domes-
tication,’’ vol. i. pp. 250, 256. In regard to the higher animals, the sexual
differences which have arisen under domestication are described in the same
work under the head of each species.
SEXUAL SELECTION 815
which exists in many natural species and domesticated
races, between the period of the development of their char-
acters and the manner of their transmission—for example,
the striking fact of the early growth of the horns in the rein-
deer, 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 charac-
ters being inherited by both sexes is their development at
an early age, while the sexes differ but little in constitution.
It appears, however, that some difference must exist be-
tween 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
discussion 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 atthe
same age, and periodically at the same season of the year,
in which they first 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 ardor 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 by natural selection tending toward the
general welfare of the species. Hence the manner in which
816 THE DESCENT OF MAN
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
transmitted to the same sex at the same age, the other sex
and the young are left unmodified. 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 dis-
covering 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 modified 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
characters of the adult males; and differences of this kind
between the old and young males may be observed in many
species of animals.
. Itis probable that young male animals have often tended
to vary ina manner which would not only have been of no
use to them at an early age, but would have been actu-
ally injurious—as by acquiring bright colors, which would
render them conspicuous to their enemies, or by acquiring
structures, such as great horns, which would expend much
vital force in their development. Variations of this kind
SEXUAL SELECTION 317
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 de-
rived 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 evi-
dence with domesticated animals that variations of all kinds
are, if not carefully selected, soon lost through intercrossing
and accidental deaths. Consequently, 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 char-
acters 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 conse-
quence be modified in the same manner, although such
characters were of no use to the females; but I shall here-
after 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 accumulated 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 accumulated through natural selec-
tion, 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
818 THE DESCENT OF MAN
classes. But this implies that the two sexes follow different
habits in their struggles for existence, which is a rare cir-
cumstance with the higher animals. The case, however, is
widely different with the reproductive functions, in which
respect the sexes necessarily differ. For variations in struc-
ture 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 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 ef the secondary
sexual characters in animals of all classes, and shall endeavor
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 illus-
trative 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 al-
lures 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 year.y was
SEXUAL SELECTION 319
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 Buckinghamshire (where about 5,000 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; while in North Wales (where the average
annual births are 12,878) it was as high as 106.2 to 100.
Taking a still smaller district, viz., Rutlandshire (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 7,885 births, during the
whole ten years, was as 104.5 to 100; that is, in the same
ratio as throughout England.** The proportions are some-
times slightly disturbed by unknown causes; thus Prof.
Faye states ‘‘that in some districts of Norway there has
been during a decennial period a steady deficiency of boys,
while 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 Russia the average proportion is as high as 108.9, and in
Philadelphia, in the United States, as 110.5 to 100. The
average for 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 suc-
cessive years between 90 and 99 males for every 100 females.
It is a singular fact that with Jews the proportion of male
48 “Twenty-ninth Annual Report of the Registrar-General for 1866.’? In
this report (p. xii.) a special decennial table is given.
49 For Norway and Russia, see abstract of Prof. Faye’s researches, in
“British and Foreign Medico-Chirurg. Review,’’ April, 1867, pp. 343, 345,
For France, the ‘‘Annuaire pour J’An 1867,’’ p, 213, For Philadelphia,
Dr. Stockton-Hough, ‘‘Social Science Assoc.,’? 1874. For the Cape of Good
Hope, Quetelet as quoted by Dr, H. H, Zouteveen, in the Dutch translation of
this work (vol. i, p. 417), where much information is given on the proportion
of the sexes.
820 THE DESCENT OF MAN
births is decidedly larger than with Christians: thus in
Prussia the proportion is as 118, 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.° 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-born females
we have in several countries from 184.6 to 144.9 still-born
males. During the first four or five years of life, also, 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 unfavorable.’ *
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
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 female infants is another cause; for the males
are thus more liable to be injured during parturition. Con-
sequently the still-born males are more numerous; and, as
a highly competent judge, Dr. Crichton Browne,” believes,
male infants often suffer in health for some years after birth.
Owing to this excess in the death-rate of male children, both
50 In regard to the Jews, see M. Thury, ‘‘La Loi de Production des Sexes,”’
1863, p. 25.
51 ‘British and Foreign Medico-Chirurg. Review,’’ April, 1867, ‘p. 343,
Dr. Stark also remaris (‘‘Tenth Annual Report of Births, Deaths, etc., in Scot-
land,’’ 1867, p. xxviii.) that ‘‘These examples may suffice to show that, at
almost every stage of life, the males in Scotland have a greater liability to death
and a higher death-rate than the females, The fact, however, of this pecu-
larity being most strongly developed at that infantile period of life when the
dress, food, and general treatment of both sexes are alike, seems to prove that
the higher male death-rate 1s an impressed, natural, and constitutional peculiarity
due to sex alone.”’
52 “West Riding Lunatic Asylum Reports,’’ vol. i, 1871, p. 8. Sir J.
Simpson has proved that the head of the male infant exceeds that of the female
by threv-eights of an inch in circumference, and by one-eighth in transverse
diameter. Quetelet has shown that woman is born smaller than man; see
Dr. Duncan, ‘‘Fecundity, Fertility, Sterility,’’ 1871, p. 382.
SEXUAL SELECTION 321
at birth and for some time subsequently, and owing to the
exposure of grown men to various dangers, and to their
tendency to emigrate, the females in all old-settled coun-
tries, where statistical records have been kept," 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, Engiand, and the
United States, the excess of male over female births is
less when they are illegitimate than when legitimate.”
This has been explained by different writers in many dif-
ferent ways, as from the mothers being generally young,
from the large proportion of first pregnancies, etc. But
we 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 labors, from vari-
ous causes, such as attempts at concealment by tight lacing,
hard work, distress of mind, etc., their male infants would
proportionably suffer. And this probably is the most effi-
cient of all the causes of the proportion of males to females
born alive being less among illegitimate children than among
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 struggles for the pos-
session 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 we have the curious fact that we may attrib-
ute the more frequent deaths of male than female infants,
especially among the illegitimate, at least in part to sexual
selection.
It has often been supposed that the relative age of the
53 With the savage Guaranys of Paraguay, according to the accurate Azara
(“Voyages dans l’Amerique mérid.,”’ tom. ii., 1809, pp. 60, 179), the women
are to the men in the proportion of 14 to 13.
54 Babbage, ‘‘Edinburgh Journal of Science,’’ 1829, vol. i. p. 88; also p. 90,
on still-vorn children. On illegitimate children in England, see ‘‘Report of
Registrar General for 1866 ”’ p. xv.
822 THE DESCENT OF MAN
two parents determines the sex of the offspring; and Prof.
Leuckart® has advanced what he considers sufficient evi-
dence, with respect to man and certain domesticated animals,
that this is one important 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 observations discountenance this
belief. According to Dr. Stockton-Hough,® the season of
the year, the poverty or wealth of the parents, residence
in the country or in cities, the crossing of foreign immi-
grants, etc., 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 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 En-
glish race-horse, and we shall immediately see that his male
and female offspring 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 during 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, consisting of
12,763 males and 12,797 females, or in the proportion of 99.7
55 Leuckart (in Wagner, ‘‘Handworterbuch der Phys.,’’ B, iv., 1853, s. 774),
56 Social Science Assoc, of Phila., 1874.
51 “Anthropological Review,’’ April, 1870, p. eviii.
* 58 During eleven years a record was kept of the number of mares which
proved barren or prematurely slipped their foals; and it deserves notice, as
showing how infertile these highly nurtured and rather closely interbred ani-
mals have become, that not far from one-third of the mares failed to produce liv-
ing foals. Thus during 1866, 809 male colts and 816 female colts were born,
and 743 mares failed to produce offspring. During 1867, 836 males aad 902
females were born, and 794 mares failed.
SEXUAL SELECTION 823
males to100 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 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 the females during six
successive years; and the females exceeded the males during ©
two periods each of four years: this, however, may be ac-
cidental; 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, through-
out England, were sent to the ‘‘Field’’ newspaper; and I am
again indebted to Mr. Tegetmeier for carefully tabulating
the results. The recorded births were 6,878, consisting of
8,605 males and 3,273 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 inquired 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 agri-
culturists 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
824 THE DESCENT OF MAN
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 man-
kind, and both cases probably depend on the same cause.
I have received returns from four gentlemen in England
who have bred Lowland sheep, chiefly Leicesters, during
the last ten to sixteen years; they amount altogether to 8,965
births, consisting of 4,407 males and 4,558 females; that is
in the proportion of 96.7 males to 100 females. With respect
to Cheviot and blackfaced sheep bred in Scotland, I have
received returns from six breeders, two of them on a large
scale, chiefly for the years 1867-69, 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 80,172
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.
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-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 84 calves born on a farm in Derby-
shire, only one was a bull. Mr. Harrison Weir has inquired
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 Rabbits for many years, and has noticed
59 T am much indebted to Mr. Cupples for having procured for me the above
returns from Scotland, as well as some of the following returns on cattle. Mr.
R. Elliot, of Laighwood, first called my attention to the premature deaths of the
males—a statement subsequently confirmed by Mr. Aitchison and others. To
this latter gentleman, and to Mr. Payan, I owe my thanks for large returns
as to sheep.
SEXUAL SELECTION 825
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 re-
ceived 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 subse-
quently 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 than the females;’’ “ and
as the catching of these animals is a special occupation the
statement may perhaps be trusted. Sir A. Smith, in de-
scribing an antelope of South Africa” (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 fo the many beasts of
prey of the country.
Birds.—W ith respect to the Fowl, I have received only
one account, namely, that out of 1,001 chickens of a highly
bred stock of Cochins, reared during eight years by Mr.
Stretch, 487 proved males, and 514 females; 7.¢., 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. Tegetmeier informs me, can always be pur-
chased cheaper than females. Usually the two birds reared
60 Bell, “History of British Quadrupeds,’’ p. 100,
*! ‘THustrations of the Zoology of 8. Africa,’ 1849, pl. 29,
826 THE DESCENT OF MAN
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” are convinced that the males 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” that in Scandinavia the broods of the capercailzie
and biackcock 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; but this lat-
ter 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,“ 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 inquiring
from the dealers, who receive at certain seasons large num-
bers of ruffs (Machetes pugnax), was told that the males
are much the more numerous. This same naturalist has
also inquired for me from the bird-catchers, who annually
catch an astonishing number of various small species alive
for the London market, and he was unhesitatingly 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 8. The males of
6 Brehm (“Tlust. Thierleben,”’ B. iv. s. 990) comes to the same conclusion,
63 Qn the authority of L. Lloyd, ‘‘Game Birds of Sweden,’’ 1867, pp.
12, 132.
64 “Nat. Hist. of Selborne,’’ letter xxix., edit. of 1825, vol. i. p. 139.
6 Mr, Jenner Weir received similar information, on making inquiries during
the following year. To show the number of living chaffinches caught, I may
SEXUAL SELECTION 3827
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, but 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 88 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” 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’’; while in Palestine Mr. Tristram
found ‘‘the male flocks appearing greatly to exceed the
female in number.’’” So again with the Quiscalus major,
Mr. G. Taylor® says that in Florida there were ‘‘very few
females in proportion to the males,’’ while in Honduras the
mention that in 1869 there was a match between two experts, and one man
caught in a day 62, and another 40, male chaffinches. The greatest number
ever caught by one man in a single day was 70.
86 ‘This,’ vol. ii. p. 260, as quoted in Gould’s ‘‘Trochilide,’’ 1861, p. 52,
For the foregoing proportions I am indebted to Mr. Salvin for a table of hig
results.
67 “*This,’? 1860, p. 137; and 1867, p. 369.
68 “This,’? 1862, p. 137.
828 THE DESCENT. OF MAN
proportion was the other way, the species there having the
character of a polygamist.
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.” Infertile females might readily
be mistaken for males, as Dr. Giinther has remarked to me
in regard to trout. Withsome species the males are believed
to die soon after fertilizing 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,” who has
especially attended to the natural history of the pike (Hsox
luctus), 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
the few cases in which the proportional numbers have been
actually observed, the males appear to be largely in excess.
Thus Mr. R. Buist, the superintendent of the Stormontfield
experiments, says that in 1865, out of 70 salmon first landed
for the purpose of obtaining the ova, upward of 60 were
males. In 1867 he again ‘‘calls attention to the vast dispro-
portion of the males to the females. We had at the outset
at least ten males to one female.’’ Afterward females suffi-
cient for obtaining ova were procured. He adds, ‘‘from the
great proportion of the males, they are constantly fighting
and tearing each other on the spawning-beds.’’” This dis-
proportion, no doubt, can 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
6° Leuckart quotes Bloch (Wagner, ‘‘Handwérterbuch der Phys.,’’ B. iv.,
1853, s. 775), that with fish there are twice as many males as females.
7 Quoted in the ‘‘Farmer,’’ March 18, 1869, p. 369.
11 **The Stormontfield Piscicultural Experiments,’’ 1866, p. 23. The ‘‘Field”’
newspaper, June 29, 1867. :
SEXUAL SELECTION 829
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 suffi-
cient females for obtaining ova can be found.” 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 Cyprinids likewise seem to be in ex-
cess; 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; for
the female while 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 among the males, ‘‘she
is immediately pressed closely by a male on each side; and
when they have been in that situation for a time, are super-
seded by two other males.’’ ”
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,
72 ‘“‘Tand and Water,’’ 1868, p. 41.
3 Yarrell, ‘‘Hist. British Fishes,”’ vol. i, 1826, p. 307; on the Cyprinus
carpio, p. 331; on the Finca vulgaris, p. 331; on the Abramis brama, p. 336,
See, for the minnow (Leuciscus phoxinus), ‘‘Loudon’s Mag. of Nat. Hist. ,’’ vol.
v., 1832, p. 682.
830 THE DESCENT OF MAN
I cannot find 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 Prof. 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 cynthia),
the males greatly preponderate in the first, while 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 ob-
servers have been much struck by the apparently enormous
preponderance of the males." Thus Mr. Bates,” in speak-
ing 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 proportion 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. turnus this is certainly
the case. In South Africa, Mr. R. Trimen found the males
in excess in 19 species;” and in one of these, which swarms
in open 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.” Myr. 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” states that the
™ Leuckart quotes Meinecke (Wagner, ‘‘Handworterbuch der Phys.,’’ B. iv.,
1853, s. 775) that the males of Butterflies are three or four times as numerous
as the females.
78 “The Naturalist on the Amazons,”’ vol. ii., 1863, pp. 228, 347.
76 Four of these cases are given by Mr. Trimen in his ‘‘Rhopalocera Africa
Australis, ”’
™ Quoted by Trimen, ‘‘Transact. Ent. Soc.,”’ vol. v. part iv., 1866, p. 330.
% ‘Transact. Linn. Soc.,’’ vol. xxv. p. 37.
SEXUAL SELECTION 831
females of Ornithoptera cresus, in the Malay Archipelago,
are more common and more easily caught than the males;
but this is a rare butterfly. I may here add, that in
Hyperythra, a genus of moths, Guenée 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,” 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 attrib-
uted 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 beginning of the sea-
son, and the females at the end, from the want of mates.*.
I cannot, however, persuade myself that these causes suffice
to explain the great excess of males in the above cases of
certain butterflies which are 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
his view. Mr. Doubleday, however, and some others take
an opposite view, and are convinced 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 places their fre-
quenting more open stations, other causes may be assigned
7 ‘Proc, Entomolog. Soc.,’’ Feb. 17, 1868. /
89 Quoted by Dr. Wallace in ‘‘Proc, Ent. Soc.,’’ 3d series, vol. v., 1867, p. 487.
832 THE DESCENT OF MAN
for an apparent or real difference in the proportional num-
bers of the sexes of Lepidoptera, when captured in the
imago state, and when reared from the egg or caterpillar
state. I hear from Prof. 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 sur-
rounded by caterpillars would probably devour the largest;
and Prof. Canestrini informs me that in Italy some breed-
ers believe, though on insufficient evidence, that in the
first broods of the Ailanthus silk-moth the wasps destroy
a larger number of the female than of the male caterpil-
lars. Dr. Wallace further remarks that female caterpillars,
from being larger than the males, require more time for
their development, and consume more food and moisture;
and thus they would be exposed during a longer time to
danger from ichneumons, birds, etc., and in times of scarcity
would perish in greater numbers. Hence it appears quite
possible that, 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 congre-
gate in extraordinary numbers round a single female ap-
parently 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 con-
gregated round a female Hlachista rufocinerea. It is well
SEXUAL SELECTION = 333
known that if a virgin Lasiocampa quercus or Saturnia
carpint 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 con-
finement. In the Isle of Wight Mr. Trimen exposed a box
in which a female of the Lasiocampa had been confined
on the previous day, and five males soon endeavored 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.*
Mr. Doubleday has called my attention to M. Stau-
dinger’s” list of Lepidoptera, which gives the prices of the
males and females of 800 species of 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 males exceed the females in the same proportion. About
2,000 species or varieties of moths (Heterocera) are cata-
logued, those with wingless females being here excluded
on account of the difference in habits between the two
sexes: of these 2,000 species, 141 differ in price accord-
ing 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 148. With respect to the butterflies in this price
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
81 Blanchard, ‘‘Metamorphoses, Mceurs des Insectes,’’ 1868, pp. 225-226,
82 “I enidopteren-Doubletten Liste,’’ Berlin, No, x., 1866.
384 THE DESCENT OF MAN
excess in the number of the males. But I am bound to add
that Dr. Staudinger informs me that he is himself of a dif-
ferent 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 while 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 from eggs or caterpillars, I have received only the few
following cases:
Males | Females
The Rev. J. Hellins,* of Exeter, reared, during 1868, mmaEeH
of 73 species, which consisted of . . 153 137
Mr. Albert Jones, of Eltham, reared, pees 1868, imagos of 9
species, which consisted of . . . -| 159 126
During 1869 he reared imagos from 4 species, “consisting of .| 114 112
Mr. Buckler, of Emsworth, Hants, during 1869, reared imagos
from 74 species, consisting of . 180 169
Dr. Wallace, of Colchester, reared from ‘one brood of Bombyx
cynthia . . 52 48
Dr, Wallace raised, from cocoons of Bombyx Pernyi_ sent from
China, during 1869. . . 224 123
Dr. Wallace raised, during 1868 and 1869, from two lots of
cocoons of Bombyx yamamai . . 2. 2 es 6 we we 52 46
Totals . 2. 2 6 © © © eo ew we we ww ew ff 984 161
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
8 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 found it impossible to tabulate them.
SEXUAL SELECTION 835
of Lepidoptera, the mature males generally exceed the fe-
males in number, whatever the proportions may be at their
first emergence from the egg.
With reference to the other orders of insects, I have been
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 Elateride,
the males are said to be much more numerous than the
females, and ‘‘two or three are often found united with one
female;* so that here polyandry seems to prevail.’’ With
Siagonium (Staphylinide), in which the males are furnished
with horns, ‘‘the females are far more numerous than the
‘opposite sex.’’ Mr. Janson stated at the Entomological
Society that the females of the bark-feeding Tomicus villosus
are so common as to bea plague, while the males are so rare
as to be hardly known.
It is hardly worth while saying anything about the pro-
portion of the sexes in certain species and even groups
of insects, for the males are unknown or very rare, and the
females are parthenogenetic, that is, fertile without sexual
union; examples of this are afforded by several of the
Cynipide.** In all the gall-making Cynipide known to
Mr. Walsh, the females are four or five times as numerous
as the males; and so it is, as he informs me, with the gall-
making Cecidomyiiz (Diptera). With some common species
of Saw-flies (Tenthredine) Mr. F. Smith has reared hun-
dreds of specimens from larve of all sizes, but has never
reared a single male; on the other hand, Curtis says,** that
8 Giinther’s ‘‘Record of Zoological Literature,’’ 1867, p. 260. On the ex-
cess of female Lucanus, ibid. p. 250. On the males of Lucanus in England,
Westwood, ‘‘Modern Class. of Insects,’’ vol. i. p. 187. On the Siagonium,
ibid. p. 172.
85 Walsh, in ‘“‘The American Entomologist,’ vol. i., 1869, p. 103. F. Smith,
“Record of Zoological Literature,’’ 1867, p. 328.
86 ‘Farm Insects,’’ pp. 45-46.
836 THE DESCENT OF MAN
with certain species (Athalia) bred by him, the males were
to the females as six to one; while exactly the reverse oc-
curred with the mature insects of the same species caught
in the fields. In the family of Bees, Hermann Miiller® col-
lected 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 prac-
tically in excess. Miiller also observed that the relative
number of the two sexes in some species differed much
in different localities. But as H. Miller has himself re-
marked 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 Miller, has noticed
in Brazil that the two sexes of the same species of bee some-
times frequent different kinds of flowers. With respect to
the Orthoptera, I know hardly anything about the relative
number of the sexes; Kérte,* 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 Hetzrina, 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,
while 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, while with other species of the same genus
both sexes are common.” In England, Mr. MacLachlan
87 “Anwendung der Darwin’schen Lehre,”’ ‘‘Verh, d. n. V. Jahrg.’’ xxiv.
8 “Die Strich, Zug oder Wanderheuschrecke,’’ 1828, p. 20.
8 “Observations on N. American Neuroptera,’? by H. Hagen and B. D.
Walsh, ‘‘Proc. Ent Soc. Philadelphia,’’ Oct. 1863, pp. 168, 223, 239.
SEXUAL SELECTION 887
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.” With most of
these species (excepting the Tenthredinz) 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 less information. With Spiders, Mr. Black-
wall, who has carefully attended to this 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." The small size of the males in comparison with
the females (a peculiarity which is sometimes carried to an
extreme degree), and their widely different appearance, may
account in some instances for their rarity in collections.”
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® carefully examined no less
than 18,000 specimens of Apus from twenty-one localities,
and among these he found only 319 males. With some
other forms (as Tanais and Cypris), as Fritz Miller 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 Diastylide and
of Cypridina on the shores of Brazil; thus with a species
% ‘Proc, Ent. Soe. London,’? Feb, 17, 1868.
*1 Another great authority with respect to this class, Prof. Thorell of Upsala
(‘On European Spiders,’’ 1869-70, part i. p. 205) speaks as if female spiders
were generally commoner than the males,
® See, on this subject, Mr. O. P. Cambridge, as quoted in eee Jour-
nal of Science, »? 1868, p. 429.
% “Reitrige zor Parthenogenesis, ” p. 174,
Descent—Vox. i.—15
538 THE DESCENT OF MAN
in the latter genus, 63 specimens caught the same day in-
cluded 57 males; but he suggests that this preponderance
may be due to some unknown difference in the habits of
the two sexes. With one of the higher Brazilian crabs,
namely, a Gelasimus, Fritz Miiller found the males to be
more numerous than the females. According to the large
experience of Mr. C. Spence Bate, the reverse seems to 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, for instance, that of pro-
ducing 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*t has recently found on
careful examination that the Todas, a hill-tribe of India,
consist of 112 males and 84 females of all ages—that is ina
ratio of 183.8 males to 100 females. The Todas, who are
polyandrous in their marriages, during former times invari-
ably practiced female infanticide; but this practice has now
been discontinued for a considerable period. Of the chil-
dren born within late years, the males are more numerous
than the females, in the proportion of 124 to 100. Col.
Marshall accounts for this fact in the following ingenious
% “The Todas,’? 1873, pp. 100, 111, 194, 196,
SEXUAL SELECTION 339
manner: ‘‘Let us for the purpose of illustration 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, while the third mother
has three sons and three daughters. The first mother, fol-
lowing the tribal custom, destroys four daughters and pre-
serves 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 while the
males belong to families in which the tendency to produce
sons is great, the females are of those of a converse inclina-
tion. Thus the bias strengthens with each generation, until,
as we find, 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 extremely scanty, I have searched for ad-
ditional 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
practiced infanticide; and Mr. Fenton’ states that he ‘‘has
met with instances of women who have destroyed four, six,
and even seven children, mostly females. However, the
universal testimony of those best qualified to judge is con-
clusive that this custom has for many years been almost ex-
tinct. Probably the year 1835 may be named as the period
of its ceasing to exist.’’ Now among the New Zealanders
as with the Todas, male births are considerably in excess,
Mr. Fenton remarks (p. 80): ‘‘One fact is certain, although
the exact period of the commencement of this singular con-
dition of the disproportion of the sexes cannot be demon-
stratively fixed, it is quite clear that this course of decrease
was in full operation during the years 1830 to 1844, when
% ‘‘Aborigina Inhabitants of New Zealand; Government Report,’ 1859,
p. 36.
840 THE DESCENT OF MAN
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 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 civilized 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 practiced there to a
frightful extent, but was by no means confined to female
infants, as is shown by Mr. Ellis,** and as I have been in-
formed by Bishop Staley and the Rev. Mr. Coan. Never-
theless, another apparently trustworthy writer, Mr. Jarves,”
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’’; 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 prob-
9 **Narrative of a Tour through Hawaii,’’ 1826, p. 298.
¥ “History of the Sandwich Islands,’ 1843, p. 93.
SEXUAL SELECTION 841
able, but must be received with much caution. The prac-
tice 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 4,728 males and 8,776 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 1,797, and of females of the same ages
1,429; and here we have the ratio of 125.75 males to 100
females.
In a census of all the islands in 1850 the males of all
ages amounted to 36,272, and the females to 83,128, or as
109.49 to 100. The males under seventeen years amounted
to 10,778, and the females under the same age to 9,598, or
as 112.3 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
civilized countries, the proportion of males would have been
considerably higher if the numbers had referred to births.”
% This is given in the Rev. H. T. Cheever’s ‘‘Life in the Sandwich Islands,”
1851, p. 277.
39 Dr. Coulter, in describing (‘‘Journal R. Geograph. Soc.,’’ vol. v., 1835, p.
67) the state of California about the year 1830, says that the natives, reclaimed
by the Spanish missionaries, have nearly all perished, or are perishing, although
well treated, not driven from their native land, and kept from the use of spirits.
He attributes this, in great part, to the undoubted fact that the men greatly ex-
ceed the women in number; but he does not know whether this is due to a fail-
ure of female offspring, or to more females dying during early youth. The latter
alternative, according to all analogy, is very improbable. -He adds that ‘‘infanti-
cide, properly so called, is not common, though very frequent recourse is had
to abortion.’’ 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 fer-
tility has been diminished from changed habits of life.
I had hoped to gain some light on this subject from the breeding of dogs;
fnasmuch 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. Unfortu-
nately, I know nothing of 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
842 THE DESCENT OF MAN
From the several foregoing cases we have some reason
to believe that infanticide practiced in the manner above
explained tends to make a male-producing race; but I am
far from supposing 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. Be-
sides the several causes previously alluded to, the greater
facility of parturition among savages, and the less conse-
quent 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 Norfolk Island.
As the males and females of many animals differ some-
what in habits and are exposed in different degrees to dan-
ger, 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 complication 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 para-
mount importance, we can see that those communities would
flourish best which contained females having a strong in-
herited tendency to produce more and more females; and
from inquiries made from many breeders, it seems that the females are in some
Tespects 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,
Therefore 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, the females
are slightly in excess,
SEXUAL SELECTION 343
in such cases an unequal sex-producing tendency would
be ultimately gained through natural selection. With ani-
mals 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 preponderance of xen in
the tribe is supposed to be one chief cause of t!:¢ practice
of female infanticide.
In no case, as far as we can see, would sa inherited
tendency to produce both sexes in equal numbers, or to
produce one sex in excess, be a direct advantage or dis-
advantage to certain individuals more than {o 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 cirripeds) in which two
or more males appear to be necessary for the fertilization 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 would follow
from natural selection, but I now see that the whole prob-
lem is so intricate that it is safer to leave its solution.
for the future.
344 THE DESCENT OF MAN
CHAPTER IX
SECONDARY SEXUAL CHARACTERS IN THE LOWER CLASSES
OF THE ANIMAL KINGDOM
These characters absent in the lowest classes—Brilliant colors—Mollusca—
Annelids—Crustacea, secondary sexual characters strongly developed;
dimorphism; color; characters not acquired before maturity—Spiders,
sexual colors of; stridulation by the males—Myriapoda '
ITH animals belonging to the lower classes, the
\ \/ two sexes are not rarely united in the same
individual, and therefore secondary sexual char-
acters cannot be developed. In many cases where the sexes
are separate, both are permanently attached to some support,
and the one cannot search or struggle for the other. More-
over, it is almost certain that these animals have too imper-
fect 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 Pro-
tozoa, Coelenterata, Echinodermata, Scolecida, secondary
sexual characters, 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 ex-
ceptions occur; thus, as I hear from Dr. Baird, the males
of certain Entozoa, or internal parasitic worms, differ
slightly in color 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 propa-
gation of the species, are independent of sexual selection,
and have been acquired through ordinary selection.
SEXUAL SELECTION 845
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 (Actiniz), some
jelly-fish (Meduse, Porpita, etc.), some Planariz, many
star-fishes, Hchini, Ascidians, etc.; 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 colors do not serve as a sexual attraction, and
have not been acquired through sexual selection. It should
be borne in mind that in no case have we sufficient evidence
that colors have been thus acquired, except where one sex
is much more brilliantly or conspicuously colored than the
other, and where there is no difference in habits between
the sexes sufficient to account for their different colors.
- But the evidence is rendered as complete as it can ever be,
only when the more ornamented individuals, almost always
the males, voluntarily display their attractions before the
other sex; for we cannot believe that such display is use-
less, and if it be advantageous, sexual selection will almost
inevitably follow. We may, however, extend this conclu-
sion to both sexes, when colored alike, if their colors 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 colors of many animals in the lowest classes?
It appears doubtful whether such colors often serve as
a protection; 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 Medusa, or
jelly-fishes, is of the highest service to them as a protection;
but when we are reminded by Hickel that not only the
medusz, but many floating mollusca, crustaceans, and even
small oceanic fishes partake of this same glass-like appear-
ance, often accompanied by prismatic colors, we can hardly
346 THE DESCENT OF MAN
doubt that they thus escape the notice of pelagic birds and
other enemies. M. Giard is also convinced’ that the bright
tints of certain sponges and ascidians serve as a protection.
Conspicuous colors are likewise beneficial to many animals
as a warning to their would-be devourers that they are dis-
tasteful, 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 animals,
only say that their bright tints result either from the
chemical nature or the minute structure of their tissues,
independently of any benefit thus derived. Hardly any
color is finer than that of arterial blood; but there is no
reason to suppose that the color 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 ac-
quired for this purpose. So again with many animals,
especially the lower ones, the bile is richly colored; thus,
as I am informed by Mr. Hancock, the extreme beauty of
the Holide (naked sea-slugs) is chiefly due to the biliary
glands 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 de-
scribed 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 colors, it would have
been a strange fact if substances similarly colored 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 consider-
ing, never occur. Nor could they be expected in the three
1 “Archives de Zoolog Expér.,’’ Oct, 1872, p. 563,
SEXUAL SELECTION 347
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 sup-
port 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 fight-
ing with other males. As I am informed by Mr. Gary
Jeffreys, the sole external difference between the sexes con-
sists in the shell sometimes differing a little in form; for in-
stance, 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 iedeiotion 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 pul-
moniferous gasteropods, or land-snails, the pairing is pre-
ceded by courtship; for these animals, though hermaphro-
dites, are compelled by their structure to pair together.
Agassiz remarks,” ‘‘Quiconque a eu l’occasion d’observer
les amours des limacons, ne saurait mettre en doute la
séduction déployée dans les mouvements et les allures qui
préparent et accomplissent le double embrassement de ces
hermaphrodites.’’ These animals appear also susceptible
of some degree of permanent attachment: an accurate ob-
server, Mr. Lonsdale, informs me that he placed a pair
of land-snails (Helix pomatia), one of which was weakly,
in a small and ill-provided garden. After a short time
the strong and healthy individual disappeared, and was
2 “De VEspéce et de la Class.,’’ etc., 1869, p. 106.
348 THE DESCENT OF MAN
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 the Mollusca, the Cepha-
lopoda, 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 circum-
stance, 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 endeav-
ors to escape from an enemy.® Certain Cephalopoda, how-
ever, are characterized 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-disks to the female, lives for a time an inde-
pendent life. So completely does the cast-off arm resemble
a separate animal, that it was described by Cuvier as a para-
sitic worm under the name of Hectocotyle. But this mar-
vellous 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, etc., are beautifully
colored and shaped. The colors 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 influ-
ential to a certain extent; for although, as repeatedly stated
by Mr. Gwyn Jeffreys, the shells of some species living
ata profound depth are brightly colored, yet we generally
see the lower surfaces, as well as the parts covered by the
3 See, for instance, the account we I have given in my ‘Journal of
Researches, ’’ 1845, p. 7.
SEXUAL SELECTION 849
mantle, less highly colored than the upper and , exposed
surfaces.* In some cases, as with shells living among corals
or brightly tinted sea-weeds, the bright colors may serve as
a protection. -But that many of the nudibranch mollusca,
or sea-slugs, are as beautifully colored 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 colors usually
serve as a protection. With some species this may be the
case, as with one kind which lives on the green leaves of
alge, and is itself bright-green. But many brightly colored,
white, or otherwise conspicuous species do not seek conceal-
ment; while again some equally conspicuous species, as well
as other dull-colored kinds, live under stones and in dark
recesses. So that with these nudibranch mollusks, color
apparent y 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
Jeave offspring which would inherit their parents’ greater
beauty. But with such lowly organized creatures this is
extremely improbable. Nor is it at all obvious how the
offspring from the more beautiful pairs of hermaphrodites
would have any advantage over the offspring of the less
beautiful, so as to increase in number, unless indeed vigor
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 vigor-
ous females. If, indeed, brilliant colors were beneficial to
41 have given (‘‘Geolog. Observations on Volcanic Islands,’’ 1844, p. 53)
a curious instance of the influence of light on the colors of a frondescent
incrustation, deposited by the surf, on the coast-rocks of Ascension, and formed
by the solution of triturated sea-shells.
5 Dr. Morse has lately discussed this subject in his paper on the Adaptive
Coloration of Mollusca. ‘“Proceedings of the Boston Society of Natural His-
tory,’’ vol. xiv., April, 1871.
350 THE DESCENT OF MAN
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: Olass, Annelida (or Sea-
worms).—In this class, although the sexes, when separate,
sometimes differ from each other in characters of such im-
portance that they have been placed under distinct genera
or even families, yet the differences do not seem of the kind
which can be safely attributed to sexual selection. These
animals are often beautifully colored, but as the sexes do
not differ in this respect, we are but little concerned with
them. Even the Nemertians, though so lowly organized,
‘‘vie in beauty and variety of coloring with any other
group in the invertebrate series’’; yet Dr. McIntosh® cannot
discover that these colors are of any service. The seden-
tary annelids become duller-colored, according to M. Qua-
trefages,’ after the period of reproduction; and this I pre-
sume 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 individ-
uals of the same sex to struggle together in rivalry.
Sub-kingdom of the Anthropoda: Class, Crustacea.—In this
great class we first meet with undoubted secondary sexual
characters, often developed in a remarkable manner. Un-
fortunately 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, antenna, and sense-organs; the fe-
males being destitute of these organs, with their bodies
6 See his beautiful monograph on “‘British Annelids,”’ part i., 1873, p. 3.
1 See M. Perrier, ‘‘l’Origine de l’Homme d’aprés Darwin,’’ ‘“‘Revue Scien-
tifique,”’ Feb. 1873, p. 866.
SEXUAL SELECTION 851
often consisting of a mere distorted mass. But these ex-
traordinary differences between the two sexes are, no doubt,
related to their widely different habits of life, and, conse-
quently, do not concern us. In various crustaceans, be-
longing to distinct families, the anterior antennz are fur-
nished with peculiar thread-like bodies, which are believed
to act as smelling organs, and these are much more numer-
ous 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 pro-
vided males having been the more successful in finding
partners and in producing offspring. Fritz Muller has de-
scribed 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 fur-
nished with more numerous smelling-threads, and in the
other form with more powerful and more elongated chele,
or pincers, which serve to hold the female. Fritz Muller
suggests that these differences between the two male forms
of the same species may have originated in certain individ-
uals having varied in the number of the smelling-threads,
while other individuals varied in the shape and size of their
chele; so that of the former, those which were best able
to find the female, and of the latter, those which were best
able to hold her, have left the greatest number of progeny
to inherit their respective advantages. °
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
antenne of the female. In the male the modified antenna
is either swollen in the middle or angularly bent, or con-
8 ‘Pacts and Arguments for Darwin,’’ Eng. 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 crusta-
cean, the Pontoporeia affinis,
852 THE DESCENT OF MAN
verted (Fig. 4) into an elegant, and sometimes wonderfully
complex, prehensile organ.’ It serves, as I hear from Sir
J. Lubbock, to hold the female, and for this same purpose
one of the two posterior legs (2) on the same side of the body
is converted into a forceps. In an-.
other family the inferior or posterior
antenne are ‘‘curiously zigzagged’’ in
the males alone.
In the higher crustaceans the an-
terior legs are developed into chele,
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
female. In many species the chelz
are of unequal size on the opposite
sides of the body, the right-hand one
being, as I am informed by Mr. Bate,
generally, though not invariably, the
pi ae larger. This inequality is also often
Fig. 4.—Labidocera Dar- much greater in the male than in the
winii (from Lubbock). a.
Part of right anterior an-
Fe ot calc toning, female. The two chele of the male
eee ec thaacio lese ot Often differ in structure (Figs. 5, 6,
male. ¢. Ditto of female. 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 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
‘often much larger in the male than in the female, is not
known. AsI hear from Mr. Bate, the chele are sometimes
of such length and size that they cannot possibly be used
9 See Sir J. Lubbock, in ‘‘Annals and Mag. of Nat. Hist.,’’ vol. xi., 1853,
pl. i. and x.; and vol. xii., 1853, pl. vii. See also Lubbock in ‘‘Transact, Ent.
Soc.,’’ vol. iv., new series, 1856-1858, p. 8. With respect to the zigzagged
antenne mentioned below, see Fritz Miller, ‘‘Facts and Arguments for Darwin,”
1869, p. 40, footnote.
SEXUAL SELECTION 853
for carrying food to the mouth. In the males of certain
fresh-water prawns (Palemon) the right leg is avtually
longer than the whole body.” The great size of the one
leg with its cheles may aid the male in fighting with his
rivals; but this will not account for their inequality in the
Rn
' Fre. 5.—Anterior part of body of Calli: nassa (from Milne-Edwards), showing the
unequal and differently constructed right- und left-hand chelz of the male,
N.B.—The artist by mistake has reversed the drawing, and made the left-hand
chela the largest.
Fig. 6.—Second leg of male Orchestia, Bia. 7.—Ditto of female.
Tucuratinga (from Fritz Muller),
female on the opposite sides of the body. In Gelasimus,
according to a statement quoted by Milne-Edwards,'' the
male and the female live in the same burrow, and this
shows that they pair; the male closes the mouth of the
10 See a paper by Mr. C. Spence Bate, with figures, in ‘‘Proc. Zool. 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 chele of the higher crustaceans.
ul “Hist, Nat. des Orust.,’’ tom. ii., 183%, p. 50.
B54 THE DESCENT OF MAN
burrow with one of its che x», which is enormously devel-
oped; so that here it indirectly serves as a means of de-
fence. 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 her-
mit or soldier crab (Pagurus) for weeks together carries
about the shell inhabited by the female."* The sexes, how-
ever, of the common shcre-crab (Curcinus menas), as 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 pinccrs of the male; but as she is
caught and carried sbout by the male before moulting, she
could then be seized. with impunity.
Fritz Miiller sta‘es that certain species of Melita are dis-
tinguished from all other amphipods by the females having
‘the coxal lamellz of the penultimate pair of feet produced
into 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 fe-
males which were the most securely held during the act
of reproduction having left the largest number of offspring.
Another Brazilian amphipod (Orchestia Darwinii, Fig. 8)
presents a case of dimorphism, like that of Tanais; for
there are two,male forms, which differ in the structure of
their chelz.’* 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
havin;: derived certain special, but nearly equal, advan-
tages 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
2 Mr. C. Spence Bate, Brit. Assoc., ‘‘Fourth Report on the Fauna of South
Devon.”’
18 Fritz Muller, ‘‘Facts and Arguments for Darwin,’’ 1869, pp. 25-28.
SEXUAL SELECTION 855
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
¥iac. 8.—Orchestia Darwinii (from Fritz Muller), showing the differently constructed
: chele of the two male forms.
of life, and most of the Entomostraca must be excepted.
The chelz of many crustaceans are weapons well adapted
for fighting. Thus when a Devil-crab (Portunus puber) was
seen by a son of Mr. Bate fighting with a Carcinus menas,
the latter was soon thrown on its back, and had every limb
856 THE DESCENT OF MAN
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 Miiller, they
mutilated and killed one another. Mr. Bate put a large
male Carcinus menas into a pan of water, inhabited by
a female which was paired with a smaller male; but the
latter was soon dispossessed. 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 marinus,
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 shows that in the Amphipoda, an order low in
the scale, the males and females recognize 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 large
crab (Birgus latro) found on coral islands which makes
a thick bed of the picked fibres of the cocoanut, 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 depres-
sions 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 considered: A trustworthy naturalist, Mr. Gardner,"
4 “Travels in the Interior of Brazil,’? 1846, p. 111. I have given, in my
“Journal of Researches,’’ p. 463, an account of the habits of the Birgus.
SEXUAL SELECTION 857
while watching a shore-crab (Gelasimus) making its burrow,
threw some shells toward 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 diffi-
cult 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 color in the two sexes of our British crusta-
ceans, 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 tried to distinguish
by color the sexes of the several species which inhabit the
Mauritius, but failed, except with one species of Squilla,
probably S. stylifera, the male of which is described as being
‘tof a beautiful bluish green,’’ with some of the appendages
cherry-red, while the female is clouded with brown and
gray, ‘‘with the red about her much less vivid than in the
male.’’'* 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
colors. With Saphirina (an oceanic genus of Entomostraca),
the males are furnished with minute shields or cell-like
bodies, which exhibit beautiful changing colors; these are
absent in the females, and in both sexes of one species.’*
It would, however, be extremely rash to conclude that these
curious organs serve to attract the females. I am informed
18 Mr, Ch. Fraser, in ‘‘Proc, Zoolog. Soc.,’’ 1869, p. 3. I am indebted to
Mr. Bate for Dr. Power’s statement.
16 Claus, ‘‘Die freilebenden Copepoden,’’ 1863, s, 35.
358 THE DESCENT OF MAN
by Fritz Muller that in the female of a Brazilian species of
Gelasimus the whole body is of a nearly uniform grayish
brown. Inthe 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 colors are
liable to change in the course of a few minutes—the white
becoming dirty gray or even black, the green ‘‘losing much
of its brilliancy.’’ It deserves especial notice that the males
do not acquire their bright colors until they become mature.
They appear to be much more numerous than the females;
they differ also in the larger size of their chele. 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 considera-
tions it seems probable that the male in this species has
become gayly ornamented in order to attract or excite
the female.
It has just been stated that the male Gelasimus does not
acquire his conspicuous colors until mature and nearly
ready to breed. This seems a general rule in the whole
class in respect to the many remarkable structural differ-
ences 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 Muller’ gives some striking instances of
this law; thus the male sand-hopper (Orchestia) does not,
until nearly full grown, acquire his large claspers, which
are very differently constructed from those of the female;
while young, his claspers resemble those of the female.
Class, Arachnida (Spiders).—The sexes do not generally
differ much in color, but the males are often darker than
the females, as may be seen in Mr. Blackwall’s magnificent
work.** In some species, however, the difference is con-
1 “Facts and Arguments,”’ ete., p. 79.
18 “(A History of the Spiders of Great Britain,” 1861-64, For the follow-
ing facts, see pp. 77, 88, 102.
SEXUAL SELECTION 859
spicuous; thus the female of Sparassus smaragdulus is dull-
ish green, while the adult male has the abdomen of a fine
yellow, with three longitudinal stripes of rich red. In cer-
tain 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”®
remarks that in certain genera the males can be specifically
distinguished with ease, but the females with great diffi-
culty. I am informed by Mr. Blackwall that the sexes
while young usually resemble each other; and both often
undergo great changes in color during their successive
moults, before arriving at maturity. In other cases the
male alone appears to change color. Thus the male of
the above bright-colored Sparassus at first resembles 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 show
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 color 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 orna-
ments. From the extreme variability of color in the male
1 This author has recently published a valuable essay on_the “‘Caratteri
gessuali secondarii degli Arachnidi,’”’ in the ‘‘Atti della Soc. Veneto Trentina
di Sc. Nat. Padova,’’ vol. i., Fasc. 3, 1873. .
360 THE DESCENT OF MAN
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 con-
clusion from 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,* 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 ‘tin 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 bim with horror and indignation.’’?” The Rev.
O. P. Cambridge” 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 favor
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,
t.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
2 Aug. Vinson (‘‘Aranéides des Iles de la Réunion,” pl. vi. figs. 1 and 2)
gives a good instance of the small size of the male in Zpetra nigra. In this
species, as I may add, the male is testaceous and the female black, with legs
banded with red. Other even more striking cases of inequality in size between
the sexes have been recorded (‘‘Quarterly Journal of Science,”’ 1868, July,
p. 429); but I have not seen the original accounts.
"1 Kirby and Spence, ‘Introduction to Entomology,” vol, i, 1818, p. 280,
3% “Proce, Zoolog. Soc.,’? 1871, p. 621.
SEXUAL SELECTION 861
males of several species of Theridion™ have the power of
making a stridulating sound, while the females are mute.
The apparatus 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.* From the
analogy of the Orthoptera and Homoptera, to be described
in the next chapter, we may feel almost sure that the stridu-
lation 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.”*
Class, Myriapoda.—In neither of the two orders in this
class, the millipeds and centipeds, can I find any well-
marked instances of such sexual differences as more par-
ticularly concern us. In Glomeris limbata, however, and
perhaps in some few other species, the males differ slightly
in color 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 prehensile hooks
which serve to secure the female. In some species of [ulus
the tarsi of the male are furnished with membranous suckers
for the same purpose. As we shall see when we treat of
Insects, it isa much more unusual circumstance that it is the
female in Lithobius which is furnished with prehensile ap-
pendages at the extremity of her body for holding the male.”
% Theridion (Asagena, Sund.) serratipes, 4-punctatum et gutiatum; see
Westring, in. Kroyer, ‘“‘Naturhist. Tidskrift,’’ vol. iv., 1842-43, p. 349; and
vol. ii., 1846-49, p. 342. See also, for other species, ‘‘Araneze Suecicz,”’
. 184.
% Dr. H. H. van Zouteveen, in his Dutch translation of this work (vol. i.
p. 444), has collected several cases.
% Hilgendorf, however, has lately called attention to an analogous struc-
ture in some of the higher crustaceans, which seems adapted to produce sound;
see ‘Zoological Record,’? 1869, p. 603.
% Walckenaer et P. Gervais, ‘‘Hist. Nat. des Insectes: Apteres,’’ tom. iv.,
1847, pp. 17, 19, 68.
Descent—Vot. I.—16
562 THE DESCENT OF MAN
CHAPTER X
SECONDARY SEXUAL CHARACTERS OF INSECTS
Diversified structures possessed by the males for seizing the females—
Differences between the sexes, of which the meaning is not under-
stood—Difference in size between the sexes—Thysanura—Diptera—
Hemiptera—Homoptera, musical powers possessed by the males
alone—Orthoptera, musical instruments of the males, much diversi-
fied in structure; pugnacity; colors—Neuroptera, sexual differences
in color—Hymenoptera, pugnacity and colors—Coleoptera, colors;
furnished with great horns, apparently as an ornament; battles;
stridulating organs generally common to both sexes ;
N 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 plu-
mose antennese of the males of many species. In Chloéon,
one of the Ephemere, the male has great pillared eyes, of
which the famale is entirely destitute.* The ocelli are
absent in the females of certain insects, as in the Mutillide;
and here the females are likewise wingless. But 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,? “‘it
1 Sir J. Lubbock, ‘‘Transact. Linnean Soc.,”’ vol. xxv., 1866, p. 484. With.
respect to the Mutillide see Westwood, ‘‘Modern Olass. of Insects,’’ vol. ii.,
. 213,
: 2 These organs in the male often differ in closely allied species, and afford
excellent specific characters. But their importance, from a functional point
of view, as Mr. R. MacLachlan has remarked to me, has probably been over-
rated. It has been suggested that slight differences in these organs would
suffice to prevent the intercrossing of well-marked varieties or incipient species,
and would thus aid in their development. That this can hardly be the case,
we may infer from the many recorded cases (see, for instance, Bronn,
“Geschichte der Natur,’ B. ii, 1843, s. 164; and Westwood, ‘‘Transact,
SEXUAL SELECTION 363
is astonishing,’’ as Mr. B. D. Walsh* 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 sometimes
used for this purpose; thus the male Corydalis cornutus
(a neuropterous insect in some degree allied to the Dragon-
flies, etc.) has immense curved jaws, many times longer
than those of the female; and they are smooth instead of
being toothos, so that he is thus enabled to seize her with-
out injury.‘ 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 pur-
pose, 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 Prof.
Westwood observes, ‘‘are exceed-
ingly ardent, seizing their partners
round the neck with their sickle-
shaped jaws;’’* while the females
use their organs for burrowing
in sand-banks and making their
nests. :
The tarsi of the front legs are ye, 9,—Crabro cribrarius, Upper
dilated in many male beetles, or 781" mele: lower figure, female,
are furnished with broad cushions of hairs; and in many
genera of water-beetles they are armed with a round, flat
Ent. Soc.,”’ vol. iii., 1842, p. 195) of distinct species having been observed in
union. Mr, MacLachlan informs me (vide ‘‘Stett. Ent. Zeitung,’’ 1867, s, 155)
that when several species of Phryganide, which present strongly pronounced
differences of this kind, were confined together by Dr. Aug. Meyer, they
emis, and one pair produced fertile ova,
8 «The Practical Entomologist,’ Philadelphia, vol. ii., May, 1867, p. 88.
4 Mr. Walsh, ibid., p. 107.
58 **Modern Classification of Insects,’’ vol. ii., 1840, pp. 205, 206, Mr,
Walsh, who called my attention to the double use of the jaws, says that
he has repeatedly observed this fact.
364 THE DESCENT OF MAN
sucker, so that the male may adhere to the slippery body
of the female. It is a 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.® In the male of Crabro
cribrarius (Fig. 9), it is the tibia which is-
dilated into a broad horny plate, with minute
membranous dots, giving to it a singular ap-
pearance like that of a riddle.”_ In the male of
Penthe (a genus of beetles) a few of the middle
joints of the antenne are dilated and furnished
on the inferior surface with cushions of hair,
exactly like those on the tarsi of the Carabide,
‘tand 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 patterns to enable them to embrace
the neck of the female.’’ Lastly, in the males
of many insects, 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
Te. 10,— Taph-
p
roderes distortus to an extravagant length.°
much enlarged).
pper figure, T’he sexes of many species in all the orders
male; lower figure, f a : :
female. present differences of which the meaning is
not understood. One curious case is that of a beetle (Fig. 10),
®§ We have here a curious and inexplicable case of dimorphism, for some
of the females of four European species of Dytiscus, and of certain species of
Hydroporus, have their elytra smooth; and no intermediate 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 Spence, ‘‘Introduction to Entomology,”’ vol. iii., 1826, p. 305,
7 Westwood, ‘‘Modern Class.,’’ vol. ii. p. 193. The following statement
about Penthe, and others in inverted commas, are taken from Mr. Walsh
**Practical Entomologist,’’ Philadelphia, vol. ii. p. 88.
® Kirby and Spence, ‘‘Introduct.,”’ ete., vol. iii, pp. 332-336,
SEXUAL SELECTION 365
the male of which has the left mandible much enlarged; so
that the mouth is greatly distorted. In another Carabidous
beetle, Eurygnathus,’ we have the case, 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
extraordinary is that certain male butterflies have their
forelegs more or less atrophied, with the tibiz and tarsi
reduced to mere rudimentary knobs. The wings, also, in
the two sexes often differ in neuration,’? and sometimes
considerably in outline, as in the Aricoris epitus, which
was shown 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 disks of the posterior pair. In several British
butterflies, as shown 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 discussion. The male is feebly
luminous, as are the larve and even the eggs. It has been
supposed 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’* appears to have solved the diffi-
culty: he finds that all the Lampyride which he has tried
are highly distasteful to insectivorous mammals and birds.
Hence it is in accordance with Mr. Bates’s view, hereafter
to be explained, that many insects mimic the Lampyrida
closely, in order to be mistaken for them, and thus to escape
® “Insecta Maderensia,”’ 1854, p. 20.
10 E, Doubleday, ‘tAnnals 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.
11H, W, Bates, in ‘“‘Journal of Proce. Linn. Soc.,’’ vol. vi., 1862, p. 74.
Mr, Wonfor’s observations are quoted in ‘‘Popular Science Review,”’ 1868,
. B43,
2 “The Naturalist in Nicaragua,’? 1874, pp. 316-320, On the phos-
phorescence of the eggs, see ‘‘Annals and Mag. of Nat. Hist.,’” Nov. 1871,
p. 372,
366 THE DESCENT OF MAN
destruction. He further believes that the luminous species
profit by being at once recognized as unpalatable. It is
probable that the same explanation may be extended to
the Hlaters, 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 larve 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 larve 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 maie
and female cocoons of the silk-moth (Bombyx mori), thay in
France they are separated by a particular mode of weigh-
ing.** 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 acertain extent hold good with insects. But Dr. Wal-
lace has suggested a much more probable explanation. He
finds, after carefully attending to the development of the
caterpillars of Bombyx cynthia and yamamai, and especially
to that of some dwarfed caterpillars reared from a second
brood on unnatural food, ‘‘that in proportion as the indi-
vidual moth is finer, so is the time required for its meta-_
morphosis longer; and for this reason the female, which is
the larger and heavier insect, from having to carry her nu-
merous eggs, will be preceded by the male, which is smaller
and has less to mature.’’'* Now, as most insects are short-
lived, and as they are exposed to many dangers, it would
manifestly be advantageous 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
13 Robinet, ‘“‘Vers a Soie,’’ 1848, p. 207.
4 “Transact. Ent. Soc.,’’ 3d series, vol. vy. p. 486.
SEXUAL SELECTION 367
of the females; and this again would naturally follow, as
Mr. A. R. Wallace has remarked," through natural selec-
tion; 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, while the
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 which are not known to fight together, of
which the males exceed the females in size, and the mean-
ing 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 (Libellulidz) are sometimes sensibly larger, and
never smaller, than the females; 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 colors. But the most curious case,
showing 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 gen-
eral rule, are smaller than the females, and emerge about
a week before them; but among the Bees, the males of Apis
mellifica, Anthidium manicatum, and Anthophora acervorum,
18 **Journal of Proc. Ent. Soc.,’’ Feb. 4, 1867, p. lxxi. ;
16 For this and other statements on the size of the sexes, see Kirby and
Spence, ibid., vol. iii. p. 300; on the duration of life in insects, see p. 344,
868 THE DESCENT OF MAN
and among the Fossores, the males of the Methoca ichneu-
monides 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 opposition to the usual rela-
tion 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-colored, minute insects, with ugly,
almost misshapen heads and bodies. Their sexes do not
differ; but they are interesting as showing us that the males
pay sedulous court to the females even low down in the
animal scale. Sir J. Lubbock” 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 backward and forward like two playful
lambs. Then the 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 antennz; then for a bit they
stand face to face, play with their antenne, and seem to be
all in all to one another.”’
Order, Diptera (Flies).—The sexes differ little in color.
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 Ela-
phomyia, discovered by Mr. Wallace’® in New Guinea, is
29
™ See “‘The Transactions of the Linnean Society,’’ volume xxvi., 1868,
p. 296,
18 “The Malay Archipelago,”’ vol. ii., 1869, p. 313.
SEXUAL SELECTION 369
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 palmated. 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 color, edged with black, with
a pale central stripe, and as these imsects 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" has several
times seen this with the Tipulz. ‘The males of other Diptera
apparently try to win the females by their music: H. Miiller”
watched for some time two males of an Hristalis 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 (Culicidz) also seem to attract each other by
humming; and Prof. Mayer has recently ascertained that
the hairs on the antenne 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 sympa-
thetically with the graver notes, and the shorter hairs with
the higher ones. Landois also asserts that he has repeatedly
drawn 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 insects, in accordance
with their highly developed nervous system.”
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, while
19 «‘Modern Classification of Insects,”’ vol. ii., 1840, p. 526.
20 Anwendung, etc., ‘‘Verh. d. n. V. Jahrg.,”? xxix. p. 80. Mayer, in
‘‘American Naturalist,’’ 1874, p. 236. :
21 See Mr. B. T. Lowne’s interesting work, ‘‘On the Anatomy of the Blow-
fly, Musca vomitora,’’ 1870, p. 14. He remarks (p. 33) that “‘the captured
flies utter a peculiar plaintive note, and that this sound causes other flies
to disappear, ”’
370 THE DESCENT OF MAN
the females are wingless; the sexes differ in the form of
their bodies, elytra, antenne, and tarsi; but, as the signifi-
cation 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 com-
monly differ much in color; 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 colored; and
as these insects emit an extremely nauseous odor, their
conspicuous colors may serve as a signal that they are un-
palatable to insectivorous animals. In some few cases their
colors 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 Reduvide make a stridulating noise;
and, in the case of Pirates stridulus, this is said™® to be
effected by the movement of the neck within the pro-
thoracic cavity. According to Westring, Reduvius person-
atus also stridulates. But I have no reason to suppose that
this is a sexual character, excepting that with non-social
insects there seems to be no use for sound-producing organs,
unless it be as a sexual call.
Order, Homoptera.—Kvery one who has wandered in a
tropical 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
2 Westwood, ‘‘Modern Class. of Insects,”’ vol. ii. p. 473.
SEXUAL SELECTION 371
pleasing to the ears of some men.” The Cicadidw usually
sing during the day, while the Fulgoride appear to be
night-songsters. ‘The sound, according to Landois,” is pro-
duced by the vibration of the lips of the spiracles, which
are set into motion by a current of air emitted from the
trachez; but this view has lately been disputed. Dr. Powell
appears to have proved” that it is produced by the vibration
of a membrane, set into action bya special muscle. In the
living insect, while 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,** “‘the drums are now (June 6 and 7, 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 ob-
served the females coming around the drumming males.”
He adds: ‘‘This season (August, 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 Miller
writes to me from South 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 dis-
tance 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
28 These particulars are taken from Westwood’s ‘*Modern Class. of Insects,’?
vol. ii,, 1840, p. 422. See also, on the Fulgoride, Kirby and Spence, ‘‘Intro-
duct.,”’ vol. ii. p. 401.
*% “Zeitschrift fir wissenschaft Zoolog.,’’ B. xvii:, 1867, 8. 152-158.
2% “Pransact. New Zealand Institute,’’ vol. v., 1873, p. 286.
%6 IT am indebted to Mr. Walsh for having sent me this extract from a
“Journal of the Doings of Cicada septemdecim,”’ by Dr. Hartman,
372 THE DESCENT OF MAN
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 orna-
mental 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,
while the females are pale-colored or obscure.
Order, Orthoptera (Crickets and Grasshoppers).—The
males in the three saltatorial families in this Order are
remarkable for their musical powers, namely, the Achetida,
or crickets, the Locustide, for which there is no equivalent
English name, and the Acridiide, or grasshoppers. The
stridulation produced by some of the Locustide is so loud
that it can be heard during the night at the distance of a
mile,” 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, Korte
has given’ an interesting case of selection by the female of
amale. The males of this species (Pachytylus migratortus)
while 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.”
In North America the Katydid (Platyphyllum concavum,
one of the Locustide) is described* as mounting on the
upper branches of a tree, and in the evening beginning ‘“‘his
noisy babble, while rival notes issue from the neighboring
trees, and the groves resound with the call of Katy-did-she-
did the livelong night.’’ Mr. Bates, in speaking of the
European field-cricket (one of the Achetide), says, ‘‘The
male has been observed to place himself in the evening
% Guilding, ‘‘Trans. Linn. Soc.,’’ vol. xv. p. 154.
28 T state this on the authority of Képpen, “Ueber die Heuschrecken in
Siidrussland,”’ 1866, p, 32, for I have in vain endeavored to procure Kérte’s
work.
29 Gilbert White, ‘‘Nat. Hist. of Selborne,’’ vol. ii., 1825, p. 262.
20 Harris, ‘‘Insects of New England,’’ 1842, p. 128.
SEXUAL SELECTION 373
at the entrance of his burrow, and stridulate until a female
approaches, when the louder
notes are succeeded by a more
subdued tone, while the suc-
cessful musician caresses with
his antenne the mate he has
won.’’* Dr. Scudder was able
to excite one of these insects
to answer him, by rubbing on
a file with a quill." In both
sexes a remarkable auditory
apparatus has been discovered
. ‘ 1 Fia. 11.—Gryllus campestris (from Lan-
by Von Siebold, situated in dois). Bisbehend aeure. under side of
33 part of a wing nervure, much magnified,
the front legs. showing the teeth, st. Left-hand figure,
In the three Families the wpperfuriace, of wiog-cover, with thé
sounds are differently pro- which the teeth (st) are scraped.
duced. In the males of the Achetide both wing-covers
have the same apparatus; and this in the field-cricket
(Gryllus campestris, Fig. 11) consists, as de- %
scribed by Landois,™ of from 181 to 138 sharp, ae
transverse ridges or teeth (st) on the under side =
of one of the nervures of the wing-cover. This 2
toothed nervure is rapidly scraped across a 2
projecting, smooth, hard nervure (r) on the
upper surface of the opposite wing. First one
wing is rubbed over the other, and then the p19 Teeth of
movement is reversed. Both wings are raised peru of Grylius
a little at the same time, so as to increase the Landois).
resonance. In some species the wing-covers of the males
are furnished at the base with a talc-like plate.** I here
give a drawing (Fig. 12) of the teeth on the under side
31 “The Naturalist on the Amazons,’’ vol. i., 1863, p. 252. Mr. Bates gives
a very interesting discussion on the gradations in the musical apparatus of the
three families. See also Westwood, ‘‘Mod. Class.,’’ vol. ii. pp. 445, 453.
32 *“Proe, Boston Soc. of Nat. Hist.,’’ vol. xi., April, 1868,
33 *‘Nouveau Manuel d’Anat. Comp.,’? French translat., tom. i, 1850,
. 567,
# *% ‘Zeitschrift fir Wissenschaft. Zoolog.,’’ B. xvii., 1867, 3, 117.
35 Westwood, ‘“‘Modern Class. of Insects,”’ vol. i. p. 440.
874 THE DESCENT OF MAN
of the nervure of another species of Gryllus, viz., G. domes-
ticus. With respect to the formation of these teeth, Dr.
Gruber has shown® that they have been developed 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 shows that their development is in part
Fic. 13.—Chioroccelus Tanana (from Bates). a,6. Lobes of opposite wing-covers,
directly due to the stimulus from the friction of one wing
over the other.
In the Locustide 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
8 ‘Ueber den Tonapparat der Locustiden, ein Beitrag zum Darwinismus,”? _
“Zeitsch. fiir Wissensch. Zoolog.,’’ B. xxii., 1872, p. 100.
2
SEXUAL SELECTION 375
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, colored 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
of dome over the wing-covers, and which has probably
the effect of increasing the sound.’’ *
We thus see that the musical apparatus is more differen-
tiated or specialized in the Locustide (which include, I
believe, the most powerful eperformers in the Order), than
in the Achetide, in which both wing-covers have the same
structure and the same function.** Landois, however, de-
tected in one of the Locustide, 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 Locustide are descended from
a form in which, as in the existing Achetide, both wing-
covers had serrated nervures on the under surface, and
could be indifferently used as the bow; but that in the
Locustide the two wing-covers gradually became differen-
tiated and perfected, on the principle of the division of
labor, the one to act exclusively as the bow, and the other
as the fiddle. Dr. Gruber takes the same view, and has
shown that rudimentary teeth are commonly found on the
inferior surface of the right wing. By what steps the more
siniple apparatus in the Achetide originated, we do not
31 Westwood, ‘‘Modern Class, of Insects,”’ vol. i, p. 453.
38 Landois, ‘‘Zeitsch. f. Wiss. Zoolog.,’’ B, xvii., 1867, a. 121, 122,
376 THE DESCENT OF MAN
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.” 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 Acridiide, —
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
f/\ row of minute, elegant, lancet-
.5)\ shaped, elastic teeth, from 85 to
98 in number;** and these are
; scraped across the sharp, pro-
Fie. 14.—Hind-leg of Stenobothrus . ‘ F
Se es eae ee een eerste: ine
ridge, much magnified (from Landois), covers, which are thus made to
vibrate and resound. Harris*’ 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 play both fiddles together, but alter-
nately, 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 resounding board.
In Pneumora (Fig. 15), a South African genus belonging
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. ’’
“0 Landois, ibid., s. 113.
41 “Insects of New England,’’ 1842, p. 133.
SEXUAL SELECTION 877
to the same family, we meet with a new 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.“ As the male is furnished with
wings (the female being wingless), it is remarkable that the
thighs are not rubbed in the usual manner against the wing-
Fie. 15.—Pneumora (from specimens in the British Museum), Upper figure, male;
lower figure, female,
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
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
42 Westwood, ‘‘Modern Classification,’’ vol. i. p. 465.
878 THE DESCENT OF MAN
male the whole body has been converted into a musical
instrument, being distended with air, like a great pellucid
bladder, so as to increase the resonance. Mr. Trimen in-
forms 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 shown that both sexes of Hphippiger vitiwm are thus
provided, though the organs differ in the male and fe-
male 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 Locustide (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 rudi-
ments on the under surface of the wing-covers of the female
Achetidz, and on the femora of the female Acridiide. In
the Homoptera, also, the femaies have the proper musical
apparatus in a functionless state; aad we shall hereafter
meet in other divisions of the animal kingdom with many
instances of structures proper to the male being present in
a rudimenta. y condition in the female.
Landois has observed another important fact, namely,
that in the females of the Acridiide, 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 fur-
ther developed, and acquire their perfect structure at the
jast 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 extremly diversified, and are altogether different from
SEXUAL SELECTION 379
those employed by the Homoptera.** But throughout the
animal kingdom we often find the same object gained by
the most diversified means; this seems due to the whole
organization having undergone multifarious changes in the
course of ages, and as part after part varied different varia-
tions were taken advantage of for the same general purpose.
The diversity of means for producing sound in the three
families of the Orthoptera and in the Homoptera impresses
the mind with the high importance of ‘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 know, from Dr. Scudder’s remarkable discovery,
that there has been 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 stridulating apparatus of the male Locustide.”’
The insect, though in most respects related to the Neurop-
tera, 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 (@ryllus 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.** With respect to color, some exotic locusts are
beautifully ornamented; the posterior wings being marked
with red, blue, and black; but as throughout the Order the
43 Tandois has recently found in certain Orthoptera rudimentary structures
closely similar to the sound-producing organs in the Homoptera; and this is
a surprising fact. See “‘Zeitschr. fiir Wissensch. Zoolog.,’”’ B. xxii. Heft. 3,
3871, p. 348. -
“4 “Transact. Ent. Soc.,’? 3d series, vol. ii (‘Journal of Proceedings,’
. 117).
ae Yr estwrood, **Modern Class. of Insects,’’ vol. i. p. 427; for crickets, p. 446
880 ; THE DESCENT OF MAN
sexes rarely differ much in color, it is not probable that
they owe their bright tints to sexual selection. Conspicuous
colors may be of use to these insects, by giving notice that
they are unpalatable. Thus it has been observed* that a
bright-colored Indian locust was invariably rejected when
offered to birds and lizards. Some cases, however, are
known of sexual differences of color in this Order. The
male of an American cricket*’ is described as being as white
as ivory, while the female varies from almost white to
greenish-yellow or dusky. Mr. Walsh informs me that the
adult male of Spectrum femoratum (one of the Phasmide)
“is of a shining brownish-yellow color; 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*® is furnished with ‘‘a long
membranous appendage, which falls over the face like a
veil’; but what its use may be is not known.
Order, Newroptera.—Little need here be said, except as
to color. In the Ephemeride the sexes often differ slightly
in their obscure tints; but it is not probable that the males
are thus rendered attractive to the females. The Libellu-
lid, or dragon-flies, are ornamented with splendid green,
blue, yellow, and vermilion metallic tints; and the sexes
often differ. Thus, as Prof. Westwood remarks,” the males
of some of the Agrionide ‘‘are of a rich blue with black
wings, while the females are fine green with colorless
wings.”’ But in Agrion Ramburit these colors are exactly
reversed in the two sexes." In the extensive North Ameri-
cans genus of Hetzrina, the males alone have a beautiful
46 Mr. Ch. Horne, in ‘‘Proc. Ent. Soc.,’’ May 3, 1869, p. xii.
“ The Geanthus nivalis. Harris, ‘Insects of New England,’’ 1842, p. 124.
The two sexes of @. pellucidus of Europe differ, as I hear from Victor Carus,
in nearly the same manner.
4 Platyblemnus: Westwood, ‘‘Modern Clas.,’’ vol. i. p. 447.
#2 B. D. Walsh, the ‘‘Pseudo-neuroptera of Ilinois,”’ in ‘Proc. Ent. Soc.,
of Philadelphia,’ 1862, p. 362.
50 **Modern Class.,”’ vol. ii. p. 37.
51 Walsh, ibid., p. 382. I a indebted to this naturalist for the following
facts on Hetzerina, Anax, and Gomphus.
SEXUAL SELECTION 381
carmine spot at the base of each wing. In Anaz 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 color. 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 color
between the sexes of many Libellulide, it is often difficult
to say which is the more brilliant; and the ordinary colora-
tion of the two sexes is reversed, as we have just seen, in
one species of Agrion. It is not probable that their colors
in any case have been gained as a protection. Mr. Mac-
Lachlan, 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 colors
serve as a sexual attraction. Certain dragon-flies apparently
are attracted by particular colors. Mr. Patterson observed™
that the Agrionids, of which the males are blue, settled
in numbers on the blue float of a fishing line, while two
other species were attracted by shining white colors.
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 colored exactly
like the females; but that their bodies in a short time
assume a conspicuous milky-blue tint, owing to the exuda-
tion of a kind of oil, soluble in ether and alcohol. Mr. Mac-
Lachlan believes that in the male of Lzbellula depressa this
change of color does not occur until nearly a fortnight after
the metamorphosis, when the sexes are ready to pair.
Certain species of Neurothemis present, according to
Brauer,” a curious case of dimorphism, some of the females
having ordinary wings, while others have them very
richly netted, as in the males of the same species.’
52 «Trans, Ent. Soc.,’? vol. i., 1836, p. Ixxxi.
8 See abstract in the “Zoological Record’? for 1867, p. 450.
882 THE DESCENT OF MAN
Brauer ‘‘explains the phenomenon on Darwinian principles
oy 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
color, and these are invariably females. This is probably
a case of reversion; for in the true Libellule, when the
sexes differ in color, the females are orange or yellow;
so that, supposing Agrion to be descended from some
primordial form which resembled the typical Libellule in
its sexual characters, 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 fe-
male, and contending with great eagerness who shall win the
prize.’ The Atropos pulsatorius is said to make a noise
with its jaws, which is answered by other individuals.*
Order, Hymenoptera.—That inimitable observer, M.
Fabre,” 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”
' Kirby and Spence, ‘‘Introduct. to Entomology,” oi ii., 1828, p. 35.
55 Houzeau, ‘‘Les Facultés Mentales,’’ ete., tom. i. . 104.
56 See an interesting article, ‘‘The Writings of Fabre,’ ° in ‘Nat. Hist.
Review,’’ April, 1862, p. 122.
™ See the “Journal of the Proceedings of the Entomological Society’ for
September 7, 1863, p. 169.
SEXUAL SELECTION 383
says that the males of one of the saw-flies (Tenthredinz)
“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 recognizing 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
recognized and caressed one another with their antenna.
Had they been strangers they would have fought together.
Again, when two communities engage in a battle, the ants
on the same side sometimes attack each other in the general
confusion, but they soon perceive their mistake, and the
one ant soothes the other.
In this Order slight differences in color, according to sex,
are common, but conspicuous differences are rare except in
the family of Bees; yet both sexes of certain groups are
so brilliantly colored—for instance in Chrysis, in which
vermilion and metallic greens prevail—that we are tempted
to attribute the result to sexual selection. In the Ichneu-
monide, according to Mr. Walsh, the males are almost
universally lighter-colored than the females. On the other
hand, in the Tenthredinide the males are generally darker
than the females. In the Siricide the sexes frequently
differ; thus the male of Sirex juvencus is banded with
orange, while the female is dark purple; but it is difficult
to say which sex is the more ornamented. In Tremex
columbe the female is much brighter-colored 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 color. The males are generally the brighter, and, in
58 DP Huber, ‘Recherches sur les Moeurs des Fourmis,’’ 1810, pp. 150, 166,
69 “Prog, Zatomolog. Soc. of Philadelphia,’? 1866, pp. 238-239.
384 THE DESCENT OF MAN
Bombus as well as in Apathus, much more variable in color
than the females. In Anthrophora retusa the male is of a rich
fulvous-brown, while 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 Andrena fulva, are much brighter-colored
than the males. Such differences in color can hardly be
accounted for by the males being defenceless and thus
requiring protection, while the females are well defended
by their stings. H. Miiller,° who has particularly attended
to the habits of bees, attributes these differences in color in
chief part to sexual selection. That bees have a keen per-
ception of color is certain. He says that the males search
eagerly and fight for the possession of the females; and he
accounts through such contests for the mandibles of the
males being in certain species larger than those of the fe-
males. 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. Conse-
quently, in certain genera (Miiller, p. 42), the males of the
several species differ much in appearance, while the females
are almost indistinguishable; in other genera the reverse
occurs. H. Miiller believes (p. 82) that the colors gained
by one sex through sexual selection have often been trans-
ferred in a variable degree to the other sex, just as the
pollen-collecting apparatus of the females has often been
transferred to the male, to whom it is absolutely useless."
6. “Anwendung der Darwin’schen Lehre auf Bienen,’ ‘Verh. p. n. Jahrg.,””
xxix.
61 M. Perrier in his article, ‘‘La Sélection sexuelle d’aprés Darwin’’ (‘‘Revue
Scientifique,’’ Feb. 1873, p. 868), without apparently having reflected much on
the subject, objects that as the males of social bees are known to be produced
from unfertilized ova, they could not transmit new characters to their male off-
spring. This is an extraordinary objection. A female bee fertilized by a male,
which presented some character facilitating the union of the sexes, or renderad
him more attractive to the female, would lay eggs which would produce only
SEXUAL SELECTION 385
Mutilla Furopea makes a stridulating noise; and accord-
ing to Goureau both sexes have this power. He attributes
the sound to the friction of the third and preceding abdomi-
nal segments, and I find that these surfaces are marked with
very fine concentric 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 wing-
less. 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 while pursuing the females.
Order, Coleoptera (Beetles).—Many beetles are colored 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 colors, which are often arranged in stripes, spots,
crosses, and other elegant patterns. Such colors can hardly
serve directly as a protection, except in the case of certain
‘flower-feeding species; but they may serve as a warning or
mears of recognition, on the same principle as the phos-
phorescence of the glow-worm. As with beetles the colors
of the two sexes are generally alike, we have no evidence
that they have been gained through sexual selection; but
this is at least 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 pos-
sess other well-marked secondary sexual characters. Blind
females; but these young females would next year produce males; and will it
be pretended that such males would not inherit the characters of their male
grandfathers? To take a case with ordinary animals as nearly parallel as pos-
sible; if a female of any white quadruped or bird were crossed by a male of a
black breed, and the male and female offspring were paired together, will it
be pretended that.the grandchildren would not inherit a tendency to blackness
from their male grandfather? The acquirement of new characters by the sterile
worker-bees is a much more difficult case, but I have endeavored to show in
my ‘‘Origin of Species’? how these sterile beings are subjected to the power
of natural selection. Bs
62 Quoted by Westwood, ‘‘Modern Class. of Insects,’’ vol. ii, p. 214.
Descent—Vou I.—17,
386 THE DESCENT OF MAN
beetles, which cannot, of course, behold each other’s beauty,
never, as I hear from Mr. Waterhouse, Jr., exhibit bright
colors, though they often have polished coats; but the
explanation of their obscurity may be that they generally
inhabit caves and other obscure stations.
Some Longicorns, especially certain Prionide, offer an
exception to the rule that the sexes of beetles do not differ
ia. 16.—Chalcosoma atlas. Upper figure, male (reduced); lower figure,
female (natural size), Y
in color. Most of these insects are large and splendidly
colored. The males in the genus Pyrodes,* which I saw
in Mr. Bates’s collection, are generally redder but rather
88 Pyrodes pulcherrimus, in which the sexes differ conspicuously, has been
described by Mr. Bates in ‘‘Transact. Ent. Soc.,’? 1869, p. 50. I will specify
the few other cases in which I have heard of a difference in color between the
sexes of beetles, Kirby and Spence (‘‘Introduct. to Entomology,”’’ vol. iii. p.
301) mention a Cantharis, Meloe, Rhagium, and the Leptura testacea; the male
of the latter being testaceous, with a black thorax, and the female of a dull red
all over. These two latter beetles belong to the family of Longicorns, Messrs,
R. Trimen and Waterhouse, Jr., inform me of two Lamellicorns, viz., a Peri-
trichia and Trichius, the male of the latter being more obscurely colored than
the female. In Tillus elongatus the male is black, and the female always, as it
is believed, of a dark-blue color, with a red thorax. The male, also, of Orso-
dacna atra, a8 I hear from Mr. Walsh, is black, the female (the so-called
O. rujicollis) having a rufous thorax.
SEXUAL SELECTION 387
duller than the females, the latter being colored 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 color 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 Prio-
nidee in which the sexes differ are colored more richly than
the males, and this does not accord with the common rule
in regard to color, 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,
etc., 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 remarkable
forms (Figs. 16 to 20). The females generally exhibit
rudiments of the horns in the form of small knobs or
ridges; but some are destitute of even the slightest rudi-
ment. On the other hand, the horns are nearly as well
developed in the female as in the male of Phaneus 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 differ-
ences 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.
In almost all cases the horns are remarkable from their
excessive 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
588 THE DESCENT OF MAN
Fia. 20.—Onthophagus rangifer (enlarged),
SEXUAL SELECTION 389
the females. Mr. Walsh" found that in Phaneus carnifex
the horns were thrice as long in some males as in others.
Mr. Bates, after examining above a hundred males of
Onthophagus 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 suppose™ 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 evi-
dence, 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 Copride, did not
find any marked difference in this respect among 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
‘Prog, Entomolog. Soc. of Philadelphia,’’ 1864, p. 228.
65 Kirby and Spence, ‘‘Introduct. Entomolog.,’’ vol. iii, p. 300.
590 THE DESCENT OF MAN
shown 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 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
Pes fare: may aid the male in clinging to the female.
from beneath. Although the males have not even a trace
of a horn on the upper surface of the body, yet the females
plainly exhibit a rudiment of a single horn on the head
(Fig. 22, a), and of a crest (0) on the thorax. That the
slight thoracic crest in the female is a rudiment of a projee
Fig. 22.—Left-hand figure, male of Onitis furcifer, viewed laterally. Right-hand
figure, female. a. Rudiment of cephalic horn. 06. Trace of thoracic horn or crest.
tion 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 pro-
jection in the same situation. So, again, there can hardly
be a doubt that the little point (a) on the head of the female
Onitis furcifer, as well as onthe head of the females of two
or three allied species, is a rudimentary representative of the
SEXUAL SELECTION 391
cephalic horn, which is common to the males of go many
Lamellicorn beetles, as in Phanwus (Fig. 18).
The old belief that rudiments have been created to com-
plete 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 to 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 de-
velopment of the large horns and projections on the lower
surface; and as these are confined to the males, the rudi-
ments of the upper horns on the females would not have
been thus obliterated.
The cases hitherto given refer to the Lamellicorns, but
an é
Fia. 8.—Bledius taurus (magnified), Left-hand figure, male; right-hand figure, female,
the males of some few other beetles, belonging to two
widely distinct groups, namely, the Curculionide and
Staphylinid, are furnished with horns—in the former on
the lower surface of the body,” in the latter on the upper
surface of the head and thorax. In the Staphylinide 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 Staphylinide, Prof. West-
wood ‘states that ‘‘male specimens can be found in the
same locality in which the central horn of the thorax is very
8 Kirby and Spence, ‘‘Introduct, Entomolog.,’’ vol. iii. p. 329,
8392 THE DESCENT OF MAN
large, but the horns of the head quite rudimental; and
others, in which the thoracic horn is much shorter, while
the protuberances on the head are long.’’*’ Here we ap-
parently 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 pos-
session of the females. Mr. Wallace® saw two males of
Leptorhynchus angustatus, a linear beetle with a much elon-
gated 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, ac-
knowledging 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-beetle (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 engage in fierce conflicts. When Mr. A. H. Davis™
inclosed 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 Lucanide, as well as of the above-
61 ‘*Modern Classification of Insects,’’ vol. i. p. 172: Siagonium, p. 172.
in the British Museum I noticed one male specimen of Siagonium in an inter-
mediate condition, so that the dimorphism is not st ‘ict.
68 “The Malay Archipelago,’’ vol. ii., 1869, p. 276. Riley, Sixth ‘‘Report
on Insects of Missouri,’’ 1874, p. 115.
6@ ““Fntomological Magazine,”’ vol. i., 1833, p. 82. See also, on the conflicts
of this species, Kirby and Spence, ibid., vol. iii, p. 314; and Westwood, ibid.,
vol. i. p. 18%.
SEXUAL SELECTION 893
mentioned Leptorhynchus, are larger and more powerful
insects than the females. The two sexes of Lethrus cepha-
lotes (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 continually pushing him on from behind; and the
battle lasts until the aggressor is killed or runs away.”
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”’ believes, would remain
on the same spot until she died.
The great mandibles of the male Luanide are extremely
variable both in size and structure, and in this respect re-
semble the horns on the head and thorax of many male
Lamellicorns and Staphylinide. A perfect series can be
formed from the best-provided to the worst-provided or
degenerate males. Although the mandibles of the common
stag-beetle, and probably of many other species, are used
as efficient 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 elaphus of North America for
seizing the female. As they are so conspicuous 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 Chiasognathus grantit of South
Chile—a splendid beetle belonging to the same family—
has enormously developed mandibles (Fig. 24); he is bold
Quoted from Fischer, in ‘‘Dict. Class. d’Hist. Nat.,’’ tom. x. p. 324.
1 “Ann, Soc, Entomolog. France,’’ 1866, as quoted in ‘‘Journal of Travel,”
by A. Murray, 1868, p. 135.
394 THE DESCENT OF MAN .
and pugnacious; when threatened he faces round, opens his
great jaws, and at the same time stridulates loudly. But
Fie. 24.—Chisognathus gran-
tii (reduced). Upper figure,
male; lower figure, female.
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 colored. Lastly, several of .
the largest beetles in the world belong
to this family, which was placed by
Linneus and Fabricius at the head
of the Order.”
Stridulating Organs.—Beetles be-
longing 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,” but it is not
comparable with that made by the
Orthoptera. The rasp generally con-
sists of a narrow, slightly raised surface, crossed by very
fine, parallel ribs, sometimes so fine as to cause iridescent
72 Westwood, ‘‘Modern Class.,’’ vol. i. p. 184.
73 Wollaston, ‘‘On Certain Musical Curculionide,” ‘‘Annals and Mag. of
Nat. Hist.,’’ vol. vi., 1860, p. 14.
SEXUAL SELECTION 895
colors, and having a very elegant appearance under the
microscope. In some cases, as with Typhceus, 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 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 scraper 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.
These organs are situated in widely different positions.
Fig. 25.—Necrophorus (from Landois). +. The two rasps. Left-hand figure, part of
the rasp highly magnified.
In the carrion-beetles (Necrophorus) two parallel rasps
(7, Fig. 25) stand on the dorsal surface of the fifth abdom-
inal segment, each rasp™ 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 Crioceridew, and in Clythra 4-
punctata (one of the Chrysomelide), and in some Tene-
brionide, etc.,”* the rasp is seated on the dorsal apex of the
™4 Landois, ‘‘Zeitschrift fiir Wiss. Zoolog.,’? B. xvii., 1867, s, 2217.
7% T am greatly indebted to Mr. G. R. Crotch for having sent me many pre-
pared 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. Iam also much
indebted to Mr. E. W. Janson, for information and specimens. I may add that
my son, Mr. F. Darwin, finds that Dermestes murinus stridulates, but he
searched in vain for the apparatus. Scolytus has lately been described by
Dr. Chapman as a stridulator, in the ‘‘Entomologist’s Monthly Magazine,”’
vol, vi. p. 130. :
896 THE DESCENT OF MAN
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.” In certain Curculionida# and Cara-
bide” the parts 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 Pelobius
Hermanni (one of Dytiscide, 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 Cerambyx heros.
Many Lamellicorns have the power of stridulating, and
the organs differ greatly in position. Some species stridu-
late very loudly, so that when Mr. F. Smith caught a Trou
sabulosus, 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 Typhceus a narrow ridge
runs obliquely across (r, Fig. 26) the coxa of each hind-leg
(having in G. stercorarius 84 ribs), which is scraped by
a specially projecting part of one of the abdominal seg-
ments. In the nearly allied Copris lunaris, an excessively
76 Schiddte, translated in ‘‘Annals and Mag. of Nat. Hist.,”’ vol. xx., 1867,
. 37,
Pn Westring has described (Kroyer, ‘‘Naturhist. Tidskrift,”’ B. ii., 1848-49,
p. 334) the stridulating organs of these two, as well as in other families. In
the Carabidz I have examined Hlaphrus uliginosus and Blethisa multipunctata,
sent to me by Mr. Crotch. In Blethisa the transverse ridges on the furrowed
border of the abdominal segment do not, as far as I could judge, come into play
in scraping the rasps on the elytra.
SEXUAL SELECTION 897
narrow fine rasp runs along the sutural margin of the elytra,
with another sharp rasp near the basal outer margin; but
in some other Coprini the rasp is seated, ‘according to
Leconte,” 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
brunnea 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 coleopter- ==
ous families the stridulating organs are won-
derfully 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 vari-
ous beetles made a shuffling or hissing noise by
the rubbing together of any hard and rough
parts of their bodies which happened to bein yg. 06. Hina.
contact; and that, from the noise thus pro- ls of Geotrupes
stercorarius (from
duced being in some way useful, the rough Lyiuis)..7 Rasp.
surfaces were gradually developed into regular * Tibia. ¢r. Tarsi.
stridulating organs. Some beetles, as they move, now pro-
duce, either intentionally or unintentionally, a shuffling
noise, without possessing any proper organs for the purpose.
Mr. Wallace informs me that the Huchirus longimanus (a
Lamellicorn, with the anterior legs wonderfully elongated
in the male) ‘‘makes, while moving, a low hissing sound
by the protrusion 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
8 I am indebted to Mr. Walsh, of Illinois, for having sent me extracts from
Leconte’s ‘Introduction to Entomology,’’ pp. 101, 143.
898 THE DESCENT OF MAN
the grating sound by rubbing the shagreened surface of
the femur against the granulated margin of the correspond-
ing 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 doubt-
ful 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. R. 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 Pelobiws which I examined, the rasp was consider-
ably larger in the male than in the female; but not so with
succeeding specimens. In Geotrupes stercorarius the rasp
appeared to me thicker, opaquer, and more promjnent 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 to the females in both the lots.
Mr. F. Smith has kept alive numerous specimens of
Monoynchus pseudacori (Curculionide) 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 dis-
covered that the males alone of two species of Heliopathes
(Tenebrionide) possess stridulating organs. I examined
SEXUAL SELECTION 399
five 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; while 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. ecribratostriatus
the male has a similar rasp, excepting that it is not partially
divided into two portions, and the female is completely desti-
tute 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 ex-
tremely fine ribs, parallel to and resembling those on the
abdominal rasp; whether these ridges serve as an indepen-
dent 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 O. 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 seg-
ment, when held in the proper light, is seen to be clothed
with hairs, which are absent or are represented by exces-
sively fine down in the males. It should be noticed that in
all Coleoptera the effective part of the rasp is destitute of
hairs. In O. 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 trans-
parent object. In the female the whole surface is covered
with little separate crests, bearing spines; while in the male
these crests in proceeding toward 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, how-
ever, of all three species of Oryctes, a slight grating or strid-
ulating sound is produced when the abdomen of a softened
specimen is pushed backward and forward.
In the case of the Heliopathes and Oryctes there can
400 | THE DESCENT OF MAN
hardly be a doubt that the males stridulate in order to
call or to excite the females; but with most beetles the
stridulation apparently serves both sexes as a mutual call.
Beetles stridulate under various emotions, in the same man-
ner as birds use their voices for many purposes besides sing-
ing to their mates. The 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. Wol-
laston and Crotch were able to discover the presence of
beetles belonging to the genus Acalles by their stridula-
tion. Lastly, the male Ateuchus stridulates to encourage
the female in ber work, and from distress when she is re-
moved.” 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 stridulation serves as a sexual call is supported by the
fact that death-ticks (Anobium tessellatum) are well known to
answer each other’s ticking, and, as I have myself observed,
a tapping noise artificially made. Mr. Doubleday also in-
forms me that he has sometimes observed a female ticking,®
and in an hour or two afterward he 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
79 M. P. de la Brulerie, as quoted in ‘‘Journal of Travel,’’? A. Murray, vol. i.,
1868, p. 135.
8 According to Mr. Doubleday, ‘‘the noise is produced by the insect raising
ctself on its legs as high as it can, and then striking its thorax five or six times,
in rapid succession, against the substance upon which it is sitting.’’? For refer-
ences on this subject see Landois, ‘‘Zeitschrift fir Wissen. Zoolog.,”’ B. xvii. s,
131. Oliver says (as quoted by Kirby and Spence, ‘‘Introduct.,’’ vol. ii. p.
393) that the female of Pimelia striata produces a rather loud sound by striking
her abdomen against any hard substance, ‘‘and that the male, obedient to this
call, soon attends her, and they pair.”’
SEXUAL SELECTION 401
best in finding partners, rugosities on various parts of their
bodies were gradually developed by means of sexual selec-
tion into true stridulating organs.
CHAPTER XI
INSECTS, continued—ORDER, LEPIDOPTERA
(BUTTERFLIES AND MOTHS)
Courtship of butterflies—Battles—Ticking noise—Colors common to both
sexes, or more brilliant in the males—Examples—Not due to the direct
action of the conditions of life—Colors adapted for protection—Colors
of moths—Display—Perceptive powers of the Lepidoptera—Variability
—Causes of the difference in color between the males and females—
Mimicry, female butterflies more brilliantly colored than the males
—Bright colors of caterpillars—Summary and concluding remarks
on the secondary sexual characters of insects—Birds and insects
compared :
the differences in color 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 fre-
quently watched one or more males pirouetting 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 cap-
i this great Order the most interesting points for us are
1 Apatura Iris: ‘The Entomologist’s Weekly Intelligence,’? 1859, p. 139.
For the Bornean Butterflies, see OC. Collingwood, ‘‘Rambles of a Naturalist,”
1868, p. 183.
402 THE DESCENT OF MAN
tured with the tips of its wings broken from a conflict with
another male. Mr. Collingwood, in spoaking of the fre-
quent battles between the butterflies of Bornoo, says, ‘They
whirl round each other with the yreatest rapidity, and appoar
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 sevoral yards: T noticod this
sound at Rio de Janciro, only when two of those butterflios
wero chasing each othor 4 in an, irregular courso, so that it is
probably made. during the courtship of the sexes.’
Some moths also produce sounds; for instance, the males
of Theophora fovea. On two occasions Mr. F. Buchanan
White" heard a sharp, quick noise made by the male of
MMylophila prasinana, and which he believes to be pro-
duced, as in Cicada, by an elastic mombrane, furnished
with a muscle. Ie quotes, also, Guonée, that Setinu pro-
duces a sound like the ticking of a watch, apparently by
the aid of ‘‘two large tympaniform vesicles, situated in the
pectoral revion’’; and these ‘tare much moro developed in
the male than in the female.’’ Ienco the sound-producing
organs in the Lepidoptera appear to stand in some relation
with the sexual functions. I have not alluded to the woll-
known noise made by the Death’s Wead Sphinx, for it is
generally heard soon after the moth has cimerged from. its
cocoon.
Girard has always observed that the musky odor which
is emitted by two species of Sphinx moths is poculiar to the
malos;* 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
2 Seo my ‘Journal of Resourchos,’’ 1845, p. 88. Mr. Doubleday has do-
tected (Proc, Hint. Soc.,’? Marchi 3, 1846, p. 128) » peculiar mombranous sac
at the base of the front wings, which is probably connected with the produc.
tion of the sound. Vor the ease of Thecophorn, seo ‘*Zoologlen) Record,’? 1469,
p. 401. For Mr, Buchanan White’s observations, “The Seotiish Naturallnt, ”
July, 1872, p. 214.
“The Scottish Naturalist, ” July, 1852, p, 218.
4 “Zoological Record,’’ 1869, p. 347.
SEXUAL SELECTION 408
many butterflies and of some moths; and it may be asked,
aro their colors and diversified patterns the result of the
direct action of the physical conditions to which these
insvots have boon exposed, without any benofit being thus
derived? Or have successive variations been accumulated
and determined as a protection, or Lor some unknown pur-
pose, or that one sox may be attractive to the other’ And,
aguin, what is the moaning of the colors boing widely dilor-
ent in the malos and females of cortain species, and alike in
the two soxes of other species of the same genus? Bofore
attempting to answer these questions a body of facts must
be givon.
With our beautiful English butterflies, the admiral, pea-
covk, and painted lady (Vaness:e), as well as many others,
tho sexes are alike. This is also the case with the magnill-
cont Heliconide, and most of the Danaide in the tropics.
But in certain other tropical groups, and in some of our
English butterflies, as the purple omporor, orange-tip, ete.
(Apatura tris and Anthocharis cardamines), the sexes differ
either greatly or slightly in color. No Isnguage suffices to
describe the splendor of the males of somo tropical species.
Eyon within the same genus wo often find specios presenting
extraordinary differences between the sexes, while others
have their sexes closely alike. Thus in the South Ameri-
can 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
soxes of which haunt the same stations (and this is not al-
ways the ease with butterflies), and which, therefore, cannot
have been differently affected by external conditions.’ In
nine of these twelve species the males rank among the most
brilliant of all butterflies, and differ so greatly from the
comparatively plain females that they wore formerly placed
in distinct gonera. The females of these nine species re-
5 Seo also Mr. Bates's papor in ‘Proc. Nut. Soo. of Philadelphia’? 1865,
P 206, Also Mr. Wallace on the samo subject, in regard to Diadema, in |
‘Transact, Entomolog. Soe. of London,’’ 1869, p, 378,
404 THE DESCENT OF MAN
semble 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 colored in nearly the same manner. In the tenth
species the female still retains the same general coloring, but
the male resembles her, so that he is colored in a much less
gaudy and contrasted manner than the males of the previous
species. In the eleventh and twelfth species the females de-
part from the usual type, for they are gayly decorated almost
like the males, but in a somewhat less degree. Hence in
these two latter species the bright colors of the males seem
to have been transferred to the females; while in the tenth
species the male has either retained or recovered the plain
colors of the female, as well as of the parent-form of the
genus. The sexes in these three cases have thus been ren-
dered nearly alike, though in an opposite manner. In the
allied genus Eubagis, both sexes of some of the species are
plain-colored and nearly alike; while with the greater num-
ber 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 coloring, so that they resemble one another much
more closely than they resemble their own males.
In the genus Papilio, all the species of the Auneas group
are remarkable for their conspicuous and strongly contrasted
colors, and they illustrate the frequent tendency to grada-
tion in the amount of difference between the sexes. Ina
few species, for instance in P. ascanius, the males and
females are alike; in others the males are either a little
brighter or very much more superb than the females. The
genus Junonia, allied to our Vanesse, offers a nearly parallel
case, for although the sexes of most of the species resemble
each other, and are destitute of rich colors, yet in certain
species, as in J. enone, the male is rather more bright-
colored than the female, and in a few (for instance e/. an-
SEXUAL SELECTION 405
dremiaja) 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 Brit-
ish Museum by Mr. A. Butler, namely, one of the tropical
American Thecle, in which both sexes are nearly alike and
wonderfully splendid; in another species the male is colored -
in a similarly gorgeous manner, while the whole upper sur-
face of the female is of a dull uniform brown. Our common
little English blue butterflies of the genus Lycena illustrate
the various differences in color between the sexes almost as
well, though not in so striking a manner, as the above exotic
genera. In Lycena agestis both sexes have wings of a brown
color, bordered with small ocellated orange spots, and are
thus alike. In ZL. egon the wings of the male are of a fine
blue, bordered with black; while those of the female are
brown, with a similar border, closely resembling the wings
of ZL. agestis. lastly, in Z. arion both sexes are of a blue
color 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 coloring 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 colored 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 gra-
dation from no difference in color 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 colors to the fe-
406- THE DESCENT OF MAN
male, or to the male having retained, or perhaps recovered,
the primordial colors of the group. It also deserves notice
that in those groups in which the sexes differ the females
usually somewhat resemble the males, so that when 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 be-
tween the sexes, and from the prevalence of the same general
type of coloration throughout the whole of the same group,
we may conclude that the causes have generally been the
same which have determined the brilliant coloring 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 colors to the
great heat and moisture of these zones; but Mr. Bates* has
shown, 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 con-
clusive when brilliantly colored males and plain-colored
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 colors
are the purposeless result of the nature of the tissues and
of the action of the surrounding conditions.
With animals of all kinds, whenever color has been modi-
fied for some special purpose, this has been, as far as we can
judge, either for direct or indirect protection, or as an attrac-
tion 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 while rest-
ing raise their wings vertically over their backs, so that the
8 “The Naturalist on the Amazons,”’ vol. i., 1863, p. 19.
SEXUAL SELECTION . 407
lower surface alone is exposed to view. Hence it is this side
which is often colored so as to imitate the objects on which
these insects commonly rest. Dr. Réssler, I believe, first
noticed the similarity of the closed wings of certain Vanessa
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’ of a common Indian and
Sumatran butterfly (Kallima), which disappears like magic
-when it settles on a bush; for it hides its head and antennz
between its closed wings, which, in form, color, and veining,
cannot be distinguished from a withered leaf with its foot-
stalk. In some other cases the lower surfaces of the wings
are brilliantly colored, and yet are protective; thus in Thecla
rubi the wings when closed are of an emerald green, and re-
semble the young leaves of the bramble, on which in spring
this butterfly may often be seen seated. It is also remark-
able that in very many species, in which the sexes differ
greatly in color on their upper surface, the lower surface
is closely similar or identical in both sexes, and serves
as a protection.°
Although the obscure tints both of the upper and under
sides of many butterflies no doubt serve to conceal them,
yet we cannot extend this view to the brilliant and con-
spicuous colors on the upper surface of such species as our
admiral and peacock Vanesse, our white cabbage-butterflies
(Pieris), or the greater 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 brimstone butterfly (Gonepteryx rhamnt)
the male is of an intense yellow, while 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,
1 See a very interesting article in the ‘‘Westminster Review”’ for July, 1867,
p. 10. A woodcut of the Kallima is given by Mr. Wallace in ‘‘Hardwicke’s
Science Gossip’’ for September, 1867, p. 196.
8 Mr. G. Fraser, in ‘‘Nature,’’ April, 1871, p. 489.
408 THE DESCENT OF MAN
and it is not credible that their difference in color should
stand in any relation to ordinary protection. Prof. Weis-
mann remarks® that the female of one of the Lycene ex-
pands 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
shows that the blue color cannot be in any way protective.
Nevertheless, it is probable that conspicuous colors 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 spe-
cies, which inhabit the same district and enjoy an immu-
nity 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 remarked to me, the females of our
orange-tip butterfly, above referred to, and of an American
species (Anth. genutia), probably show us the primordial.
colors of the parent-species of the genus; for both sexes of
four or five widely distributed species are colored 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 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 [phias
gliaucippe, 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-
colored 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."° The same reason
9 “*Rinfluss der Isolirung auf die Artbildung,’’ 1872,
10 See the interesting observations by Mr. T. W. Wood, “The Student,”
Sept. 1868, p. 81.
SEXUAL SELECTION 409
which compels us to believe that the lower surfaces have
here been colored 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 con-
fined 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 colored in an admirable
manner, as Mr. Wallace has remarked, for escaping detec-
tion. The front wings of the Bombycide and Noctuide,"
when at rest, generally overlap and conceal the hind-wings,
so that the latter might be brightly colored without much
risk; and they are in fact often thus colored. 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 colors must generally have
been acquired at some little risk. But the following fact
shows how cautious we ought to be in drawing conclusions
on this head. The common Yellow Under-wings (Triphena)
often fly about during the day or early evening, and are
then conspicuous from the color 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 colored and fragile surfaces, instead of at the body.
For instance, Mr. Weir turned into his aviary a vigorous
specimen of Triphena pronuba, which was instantly pursued
by a robin; but the bird’s attention being caught by the
colored wings, the moth was not captured until after about
fifty attempts, and small portions ot the wings were repeat-
edly broken off. He tried the same experiment in the open
air, with a swallow and Z. fimbria; but the large size of this
moth probably interfered with its capture.'? We are thus
reminded of a statement made by Mr. Wallace,’** namely,
i! Mr. Wallace in ‘‘Hardwicke’s Science Gossip,” Sept. 1867, p. 193.
12 See also, on this subject, Mr. Weir’s paper in “Transact. Ent. Society,”
1869, Pp: 23,
13 **Westminster Rev.,’’ July, 1867, p. 16.
Descent—Vou. I.—18
410 THE DESCENT OF MAN
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
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
indirectly beneficial.’’
Display.—The bright colors of many butterflies and of
some moths are specially arranged for display, so that they
may be readily seen. During the night colors are not
visible, and there can be no doubt that the nocturnal
moths, taken as a body, are much less gayly decorated than
butterflies, all of which are diurnal in their habits. But
the moths of certain families, such as the Zygeenidsx, several
Sphingide, Uraniide, some Arctiidae and Saturniide, fly
about during the-day or early evening, and many of these
are extremely beautiful, being far brighter colored than
the strictly nocturnal kinds. A few exceptional cases,
however, of bright-colored nocturnal species have been
recorded."
There is evidence of another kind in regard to display.
Butterflies, as before remarked, elevate their wings when
at rest, but while basking in the sunshine often alternately
raise and depress them, thus exposing both surfaces to full
view; and although the lower surface is often colored
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 colored than the
upper.’® In the English fritillaries (Argynnis) the lower
14 For instance, Lithosia; but Prof. Westwood (‘‘Modern Class. of Insects,’?
vol. ii. p. 390) seems surprised at this case. On the relative colors of diurnal
and nocturnal Lepidoptera, see ibid., pp. 333 and 392; also Harris, ‘‘Treatise
on the Insects of New England,”’ 1842, p. 315.
1’ Such differences between the upper and lower surfaces cf the wings of
SEXUAL SELECTION 411
surface alone is ornamented with shining silver. Never-
theless, as a general rule, the upper surface, which is prob-
ably more fully exposed, is colored more brightly and
diversely than the lower; hence the lower surface gener-
ally affords to entomologists the more useful character for
detecting the affinities of the various species. Fritz Muller
informs me that three species of Castnia are found near his
house in South Brazil: of two of them the hind-wings are
obscure, and are always covered by the front-wings 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 colored 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.’* Mr. Trimen informs me that in Guenée’s
great work three moths are figured, in which the under sur-
face is much the more brilliant. For instance, in the Aus-
tralian Gastrophora the upper surface of the fore-wing is
pale grayish-ochreous, while the lower surface is magnifi-
cently 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 coloring. Mr. Trimen also informs
me that the lower surface of the wings in certain other
Geometre"” and quadrifid Noctus are either more varie-
gated or more brightly colored than the upper surface; but
several species of Papilio may be seen in the beautiful plates to Mr. Wallace’s
‘“‘“Memoir on the Papilionide of the Malayan Region,’’ in ‘‘Transact. Linn.
Soc.,’? vol. xxv. part i., 1865,
16 See Mr. Wormald on this moth: ‘‘Proc. Ent. Soc.,’? March 2, 1868.
11 See also an account of the S. American genus Erateina (one of the Geome-
tre) in ‘‘Transact. Ent. Soc.,’’ new series, vol. v. pl. xv. and xvi,
412 THE DESCENT OF MAN
some of these species have the habit of ‘‘holding their
wings quite erect over their backs, retaining them in this
position for a considerable 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 Saturniide
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” 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.’’
It is a singular fact that no British moths which are
brilliantly colored, and, as far as I can discover, hardly
any foreign species, differ much in color according to sex;
though this is the case with many brilliant butterflies.
The male, however, of one American moth, the Saturnia
do, is described as having its fore-wings deep yellow, curi-
ously marked with purplish red spots; while the wings of
the female are purple-brown, marked with gray lines.’
The British moths which differ sexually in color are all
brown, or of various dull yellow tints, or nearly white.
In several species the males are much darker than the
females,” and these belong to groups which generally fly
18 “Prog, Ent. Soc. of London,”’ July 6, 1868, p. xxvii.
9 Harris, ‘‘Treatise,’’ ete., edited by Flint, 1862, p. 395.
20 For instance, I observe in my son’s cabinet that the males are darker
than the females in the Lasiocampa quercus, Odonestis potatoria, Hypogymna
dispar, Dasychira pudibunda, and Cycnia mendica. In this latter species the
difference in color between the two sexes is strongly marked; and Mr. Wallace
informs me that we here have, as he believes, an instance of protective mimicry
confined to one sex, as will hereafter be more fully explained. The white female
of the Cyenia resembles the very common Spilosoma menthrasti, both sexes of
which are white; and Mr. Stainton observed that this latter moth was rejected
with utter disgust by a whole brood of young turkeys, which were fond of eat-
ing other moths; so that if the Cycnia was commonly mistaken by British birds
for the Spilosoma, it would escape being devoured, and its white deceptive color
would thus be highly beneficial.
SEXUAL SELECTION 413
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.” It is probable that in these cases
_ the males are thus rendered more conspicuous, and more
easily seen by the females while flying about in the dusk.
From the several foregoing facts it is impossible to admit
that the brilliant colors of butterflies, and of some few
moths, have commonly been acquired for the sake of pro-
tection. We have seen that their colors 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 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 attachment for each other,
and that ants recognize 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 colors. They certainly discover
flowers by color. 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 endeavor to
insert their proboscis into them. Fritz Muller informs
me that several kinds of butterflies in South Brazil show
an unmistakable preference for certain colors over others: —
21 It is remarkable that in the Shetland Islands the male of this moth, instead
of differing widely from the female, frequently resembles her closely in color (see
Mr, MacLachlan, ‘‘Transact. Ent. Soc.,’’ vol. ii., 1866, p. 459). Mr. G. Fraser
suggests (‘‘Nature,”’ April, 1871, p. 489) that at the season of the year when
the ghost moth appears in these northern islands, the whiteness of the males
would not be needed to render them visible to the females in the twilight night,
414 THE DESCENT OF MAN
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 I have received other ac-
counts 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,” in speaking of the difficulty
in collecting certain butterflies in the Malay Archipelago,
states that ‘ta 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 colors of the latter will have been ren-
dered brighter by degrees, and will have been transmitted
to both sexes or to one sex, according to the law of inheri-
tance 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 fe-
male butterflies prefer the more beautiful males; thus, as I
have 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
% ‘‘Rambles of a. Naturalist in the Chinese Seas,’’ 1868, p. 182.
SEXUAL SELECTION 415
Bombycidew 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 ento-
mologists 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), as I have been told by some Continental and
English breeders. Dr. Wallace, who has had great.experi-
ence in breeding Bombyx cynthia, is convinced that the
females evince no choice or preference. He has kept above
800 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 vigor-
ous males pass over the weakly females, and are attracted
by those endowed with most vitality. Nevertheless, the
Bombycide, though obscurely colored, 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 colored 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. We
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 if, 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. But-
ler showed me several species of Callidryas in the British
Museum, in some of which the females equalled, and in
others greatly surpassed, the mates in beauty; for the
females alone have the borders of their wings suffused
with crimson and orange, and spotted with black. The
416 THE DESCENT OF MAN
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.
In England we have some analogous cases, though not
so marked. The females alone of two species of Thecla
have a bright-purple or orange patch on their fore-wings.
In Hipparchia 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 colored than their males. Again, the
females of Colias deusa and hyale have ‘‘orange or yellow
spots on the black marginal 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 com-
monly 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
butterflies the females take the more active part in the final
marriage ceremony, so that we may suppose that they like-
wise do so in the wooing; and in this case we can under-
stand how it is that they have been rendered the more _
beautiful. Mr. Meldola, from whom the foregoing state-
ments have been taken, says in conclusion: ‘Though I am
not convinced of the action of sexual selection in producing
the colors of insects, it cannot be denied that these facts are
strikingly corroborative of Mr. Darwin’s views.’’ ”
93 **Wature,’? April 27, 1871, p. 508. Mr. Meldola quotes Donzel, in ‘‘Soe. ;
Ent. de France,’’ 1837, p. 77, on the flight of buttertiies while pairing. See also
Mr. G. Fraser, in ‘‘Nature,’’ April 20, 1871, p. 489, on the sexual differences
of several British butterflies.
SEXUAL SELECTION 417
As sexual selection primarily depends on variability,
a few words must be added on this subject. In respect to
color there 1s no difficulty, for any number of highly vari-
able Lepidoptera could be named. One good instance will
suffice. Mr. Bates showed me a whole series of specimens
of Papilio sesostris and P. childrene ; 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 among the males between
the most and the least gaudy. The male of Papilio sesostris
is much less beautiful than of P. childrene; and it like-
wise varies a little in the size of the green patch on the
fore-wings, and in the occasional appearance of the small
crimson stripe on the hind-wings, borrowed, as it would
seem, from its own female; for the females of this and of
many other species in the Aineas group possess this crimson
stripe. Hence, between the brightest specimens of Papilio
sesostris and the dullest of P. childrene, there was but
a small interval; and it was evident that, as far as mere
variability 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 shown” that
the females of some species are extremely variable, the
males being nearly constant. In a future chapter I shall
_have occasion to show 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. This fact is at present inexplica-
24 Wallace on the Papilionide of the Malayan Region, in **Transact. Linn,
Soc.,”’ vol. xxv., 1865, pp. 8, 36. A striking case of a rare variety, strictly
intermediate between two other well-marked female varieties, is given by Mr,
Wallace. See also Mr. Bates, in ‘‘Proc. Entomolog. Soc.,’? Nov. 19, 1866, p. xl
25 Mr, Bates was so kind as to lay this subject before the Entomological
Society, and I have received answers to this effect from several entomologists,
418 THE DESCENT OF MAN
ble; but if it should hereafter be found that the formation
of an ocellus is due to some change in the tissues of the
wings, for instance, occurring at a very early period of
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 colored
species of Lepidoptera owe their colors to sexual selection,
excepting in certain cases, presently to be mentioned, in
which conspicuous colors have been gained through mimicry
as a protection. From the ardor 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 colored, and this undoubtedly is the
case. When both sexes are brilliantly colored and resemble
each other, the characters acquired by the males appear to
have been transmitted to both. We are led to this conclu-
sion by cases, even within the same genus, of gradation
from an extraordinary amount of difference to identity
in color between the two sexes.
But it may be asked whether the differences in color
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”
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,”
as in the adult state they are exposed to different conditions
during a very short period; and the larve of both are ex-
%¢ H. W. Bates, ‘‘The Naturalist in the Amazons,’’ vol. ii., 1863, p. 228,
A. R. Wallace, in ‘‘Transact. Linn. Soc.,’’ vol. xxv., 1865, p. 10.
27 On this whole subject see ‘‘The Variation of Animals and Plants under
Domestication,’’ 1868, vol. ii. chap. xxiii,
SEXUAL SELECTION 419
posed to the 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 colors for the sake
of protection. It seems to me, on the contrary, far more
probable that it is the males which have been chiefly modi-
fied through sexual selection, the females having been com-
paratively 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 show us approximately the primordial coloring 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 pro-
tection. In most cases the males and females of distinct
species will have been exposed during their prolonged larval
state tc different conditions, and may have been thus
affeeted; though with the males any slight change of color
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 color between the sexes are due to the
males having been modified through sexual selection for
ornamental purposes, or to the females having been modi-
fied 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
inheritance by both sexes has prevailed, the selection of
bright-colored males would tend to make the females bright-
colored, and the selection of dull-colored 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 wel] protected by
420 THE DESCENT OF MAN
obscure colors, or a greater number of males by being
brightly colored 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 favor 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 colors to the males alone,
and at the same time, or subsequently, dull colors to the
females alone. In this manner the females of some butter-
flies and moths have, it is probable, been rendered incon-
spicuous for the sake of protection, and widely different
from their males.
IT am, however, unwilling without distinct evidence to
admit that two complex processes of selection, each requir-
ing the transference of new characters to one sex alone,
have been carried on with a multitude of species—that the
males have been rendered more brilliant by beating their
rivals, and the females more dull-colored 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 protection, though it is probable that
the male acquired his bright colors as a sexual attraction.
The female of Anthocharis cardamines 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 resem-
blance 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
SEXUAL SELECTION 421
she has simply retained to a large extent her primordial
colors.
Finally, as we have seen, various considerations lead to
the conclusion that with the greater number of brilliantly
colored Lepidoptera it is the male which has been chiefly
modified through sexual selection; the amount of difference
between the sexes mostly depending on the form of inheri-
tance which has prevailed. Inheritance is governed by so
many unknown laws or conditions that it seems to us to act
in a capricious manner;** 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 iden-
tical in color. As all the successive steps in the process of
variation are necessarily transmitted 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 favor the sup-
position 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,** who thus threw a flood of
light on many obscure problems. It had previously been
observed that certain butterflies in South America, belong-
ing to quite distinct families, resembled the Heliconide so
closely in every stripe and shade of color that they could
not be distinguished save by an experienced entomologist.
As the Heliconide are colored in their usual manner, while
the others depart from the usual coloring of the groups to
which they belong, it is clear that the latter are the imi-
%8 “The Variation of Animals and Plants under Domestication,” vol. a.
ehap. xii. p. 17. uf
99 “Transact. Linn. Soc.,”? vol. xxiii., 1862, p. 495.
422 THE DESCENT OF MAN
tators, and the Heliconide the imitated. Mr. Bates fur-
ther observed that the imitating species are comparatively
rare, while the imitated abound, and that the two sets live
mingled together. From the fact of the Heliconide being
conspicuous and beautiful insects, yet so numerous in indi-
viduals and species, he concluded that they must be pro-
tected from the attacks of enemies by some secretion or
odor; and this conclusion has now been amply confirmed,”
especially by Mr. Belt. Hence Mr. Bates inferred that the
butterflies which imitate the protected species have acquired
their present marvellously deceptive appearance through va-
riation and natural selection, in order to be mistaken for the
protected kinds, and thus to escape being devoured. No
explanation is here attempted of the brilliant colors °-* +he
imitated, but only of the imitating butterflies. We mus
account for the colors of the former in the same general
manner as in the cases previously discussed in this chap-
ter. Since the publication of Mr. Bates’s 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. Riley in the United States.™
As some writers have felt much difficulty in understand-
ing 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 color. In this case
even a slight variation would be beneficial, if it rendered
the one species more like the other; and afterward the
imitated species might be modified 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 de-
30 «Proc, Ent. Soc.,’’ Dec. 3, 1866, p. xlv.
2! Wallace, ‘‘Transact. Linn. Soc.,’’ vol. xxv., 1865, p. i.* also ‘Transact.
Ent. Soc.,”’ vol. iv. (8d series), 1867, p. 301. Trimen, “‘Linn. Transact.,’’ vol.
xxvi., 1869, p. 497. Riley, ‘‘Third Annual Report on the Noxious Insects of
Missouri,’’ 1841, pp. 163-168. This latter essay is valuable, as Mr. Riley here
discusses all objections which have keen raised against Mr. Bates’s theory.
SEXUAL SELECTION 423
gree from their original condition; and they would thus
ultimately assume an appearance or coloring wholly unlike
that of the other members of the group to which they be-
longed. It should also be remembered that many species of
Lepidoptera are liable to considerable and abrupt variations
in color. 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 color, and the
sexes of the imitating form differ in a like manner. Several
cases have also been recorded where the females alone imi-
tate brilliantly colored and protected species, the males re-
taining ‘‘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 illustration of these re-
marks in a statement by Mr. Belt,” that the males of some
of the Leptalides, which imitate protected species, still re-
tain in a concealed manner some of their original charac-
ters. Thus in the males ‘‘the upper half of the lower wing
is of a pure white, while 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
2 “The Naturalist in Nicaragua,’? 1874, p. 385. ~
424 THE DESCENT OF MAN
to the females, and thus gratify their deep-seated preference
for the normal color of the Order to which the Leptalides
belong.”’
Bright Colors of Caterpillars.—While reflecting on the
beauty of many butterflies, it occurred to me that some
caterpillars were splendidly colored; and as sexual selec-
tion could not possibly have here acted, it appeared rash
to attribute the beauty of the mature insect to this agency,
unless the bright colors of their larve could be somehow
explained. In the first place, it may be observed that the
colors of caterpillars do not stand in any close correlation
with those of the mature insect. Secondly, their bright
colors do not serve in any ordinary manner as a protec-
tion. 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
for 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 colored green like the leaves
on which they feed, or being curiously like the twigs of
the trees on which they live.’’ Another instance of pro-
tection, 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 colored caterpillars were pro-
tected by having a nauseous taste; but as their skin is ex-
SEXUAL SELECTION 425
tremely tender, and as their intestines readily protrude from
@ wound, a slight peck from the beak of a bird would be as
fatal to them as if they had been devoured. Hence, as Mr.
Wallace remarks, ‘‘distastefulness alone would be insuffi-
cient 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 instantane-
ously and certainly recognized as unpalatable by all birds
and other animals. Thus the most gaudy colors would be
serviceable, and might have been gained by variation and
the survival of the most easily recognized individuals.
This hypothesis appears at first sight very bold, but when
it was brought before the Entomological Society® it was sup-
ported 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 all caterpillars of nocturnal and retiring habits with
smooth skins, all of a green color, and all which imitate
twigs, are greedily devoured by his birds. The hairy and
spinose kinds are invariably rejected, as were four conspicu-
ously colored species. When the birds rejected a caterpillar,
they plainly showed, by shaking their heads and cleansing
their beaks, that they were disgusted by the taste.“ Three
conspicuous kinds of caterpillars and moths were also given
to some lizards and frogs, by Mr. A. Butler, and were re-
jected, 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 recognized by their enemies,
on nearly the same principle that poisons are sold in colored
33 **Proe, Entomolog. Soc.,’? Dec. 3, 1866, p. xlv., and March 4, 186%,
= mee Mr, J. Jenner Weir’s paper on Insects and Insectivorous Birds, in
‘Transact. Ent. Soc.,’? 1869, p. 21; also Mr. Butler’s paper, ibid., p. 27. Mr.
Riley has given analogous facts in the “‘Third Annual Report on the N oxious
Insects of Missouri,’ 1871, p. 148. Some opposed cases are, however, given
by Dr. Wallace and M. H. d’Orville; see ‘‘Zoological Record,’’ 1869, p. 349.
426 THE DESCENT OF MAN
bottles by druggists for the good of man. We cannot, how-
ever, at present thus explain the elegant diversity in the col-
ors 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, etc., almost certainly would not be-
come uniform in color, when its tints were rendered intense
and bright; for in order to make a caterpillar merely con-
spicuous, there would be no selection in any definite direction.
Summary and Concluding Remarks on Insects.—Looking
back 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 or-
gans 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 pugna-
cious; 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
QOrthoptera, the males alone possess sound-producing organs
i1an efficient state. These are used incessantly during the
Lreeding-season, not only for calling the females, but appar-
ently for charming 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
SEXUAL SELECTION 427
these musical instruments have been acquired through sex-
ual 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 be-
fore those which were less noisy, so that their organs have
probably been gained through sexual selection. It is in-
structive 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 modifica-
tions which sometimes, as with the Homoptera, relate to
important parts of the organization.
From the reasons assigned in the last chapter, it is prob-
able that the great horns possessed by the males of many
Lamellicorn, 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 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 coloring of insects is a complex and obscure subject.
When the male differs slightly from the female, and neither
is brilliantly colored, 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
colored and differs conspicuously from the female, as with
some dragon-flies and many butterflies, it is probable that
he owes his colors to sexual selection; while the female
has retained a primordial or very ancient type of coloring,
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
428 THE DESCENT OF MAN
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 colored, there is no doubt that
they have been in a multitude of cases so colored for the
sake of protection. So it is in some instances when both
are brightly colored, 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 colors 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 color from the females, while others differ
slightly or not at all, with intermediate gradations connect-
ing these extreme states.
In the same manner as bright colors 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 Orthop-
tera have generally been transferred in a rudimentary, or
even in a nearly perfect condition, to the femaies; yet not
sufficiently perfect to be of any use. It is also an interest-
ing fact, as bearing on sexual selection, that the stridulating
organs of certain male Orthoptera are not fully developed
until the last moult; and that the colors 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.
Sexual selection implies that the more attractive individ-
uals are preferred by the opposite sex; and as with insects,
when the sexes differ, it is the male which, with some rare
exceptions, is the more ornamented, and departs more from
SEXUAL SELECTION 429
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 beau-
tiful 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 contrivances possessed by the males,
such as great jaws, adhesive cushions, spines, elongated
legs, etc., for seizing thc female; for these contrivances
show that there is some difficulty in the aci, so that her
concurrence would seem necessary. Judging from what
we know of the perceptive powers and affections of vari-
ous 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 pur-
suing the same female, we can hardly believe that the pair-
ing is left to blind chance—that the female exerts no choice,
and is not influenced by the gorgeous colors or other orna-
ments with which the male is decorated.
If we admit that the females of the Homoptera and
Orthoptera appreciate the musical tones of their male part-
ners, and that the various instruments have been perfected
through sexual selection, there is little improbability in the
females of other insects appreciating beauty in form or color,
and consequently in such characters having been thus gained
by the males. But from the circumstance of color 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 pro-
portion of cases sexual selection has played a part. This is
more especially difficult in those Orders, such as Orthoptera,
Hymenoptera, and Coleoptera, in which the two sexes rarely
differ much in color; 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
430 THE DESCENT OF MAN
species possessing weapons for sexual strife, others furnished
with wonderful horns, many with stridulating 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 some-
times take pains to display their beautiful colors; 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 colors, 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 pro-
vided with ornaments which are usually confined to the male
sex. In other groups both sexes are equally plain-colored
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 show in
further detail, is sexual selection.
END OF VOLUME ONE
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