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549 AND 551 BROADWAY. 






During the successive reprints of the first edition of this work, 
published in 1871, I was able to introduce several important 
corrections; and now that more time has elapsed, I have 
endeavoured to profit by the fiery ordeal through which the 
book has passed, and have taken advantage of all the criticisms 
which seem to me sound. I am also greatly indebted to a large 
number of correspondents for the communication of a surprising 
number of new facts and remarks. These have been so numerous, 
that I have been able to use only the more important ones ; and 
of these, as well as of the more important corrections, I will 
append a list. Some new illustrations have been introduced, 
and four of the old drawings have been replaced by better ones, 
done from life by Mr. T. W. Wood. I must especially call 
attention to some observations which I owe to the kindness of 
Prof. Huxley (given as a supplement at the end of Part I.), on 
the nature of the differences between the brains of man and the 
higher apes. I have been particularly glad to give these obser- 
vations, because during the last few years several memoirs on the 
subject have appeared on the Continent, and their importance 
has been, in some cases, greatly exaggerated by popular writers. 
I may take this opportunity of remarking that my critics 
frequently assume that I attribute all changes of corporeal 
structure and mental power exclusively to the natural selection 
of such variations as are often called spontaneous; whereas, 
even in the first edition of the ' Origin of Species,' I distinctly 
stated that great weight must be attributed to the inherited 
effects of use and disuse, with respect both to the body and 
mind. I also attributed some amount of modification to the 
direct and prolonged action cf changed conditions of life. Some 
aUowance. too, must be made for occasional reversions of 

vi Preface to the Second Edition. 

structure ; nor must we forget what I liaTe called " correlated *' 
growth, meaning, thereby, that various parts of the organisation 
are in some unknown manner so connected, that when one part 
varies, so do others; and if variations in the one are accu- 
mulated by selection, other parts will be modified. Again, it 
has been said by several critics, that when I found that many 
details of structure in man could not be explained through 
natural selection, I invented sexual selection ; I gave, however, 
a tolerably clear sketch of this principle in the first edition ol 
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 oi 
many of the half-favourable criticisms on sexual selection, with 
those which appeared at first on natural selection; such as, 
that it would exj)lain some few details, but certainly was not 
apphcable to the extent to which I have employed it. My 
conviction of the power of sexual selection remains unshaken ; 
but it is probable, or almost certain, that several of my con- 
clusions will hereafter be found erroneous ; this can hardly fail 
to be the case in the first treatment of a subject. When 
naturalists have become familiar with the jdea of sexual selection^ 
it will, as I believe, be much more largely accepted; and it 
has already been fully and favourably received by several cajDable 

Down, Beckexham, Kent, 
September 1874. 







Vol. I. 




27, note. 


32, note. 







90, note. 




124, note. 

125, note. 





20, note. 

24, note, 


72 3 








\ note. ] 


117, note. 

120, note. 

39, note. 
3G-8, note. 


55, note. 

f Discussion on the rudimentary points in the 
\ human ear revised. 
Cases of men born with hairy bodies. 
Muntegazza on the last molar tooth in man. 
Tiie rudiments of a tail in man. 

IBianconi on homologous structures, as ex- 
plained by adaptation on mcciianieal 

Intelligence in a biiboon. 

Sense of humour in dogs. 
(Further facts on imitation in man and 
\ animals. 

Reasoning power in the lower animals. 

Acquisition of experience by animals. 

Power of abstraction in animals. 
JPower of forming concepts in relation to 
\ language. . , , 

(Pleasure from certain sounds, colours, and 
\ forms. 

Fidelity in (he elephant. 

Galton on gregariousncss of cattle. 

Parental atfection. 

Persistence of enmity and hatred. 

^Nature and strength of shame, regret, and 
\ remorse. 

Snicide amongst savages. 
The motives of conduct. 
Selection, as applied to primeval man. 
Resemblances between idiots and animals. 
Division of the malar bone. 
Supernumerary mamnuo and digits. 
Further cases of mutcles projier to aninials 

appiaring in man. 
Broca : average oftpacity of slaill diniinislied 

by the preservation of the inferior members 

of society. 

viii Table of the Principal A dditions and 








208. note. 








161, note. 
























288, note 













I Belt on advantages to man from his hair- 

\ lessness. 

(Disappearance of the tail in man and certain 

\ monkeys. 

("Injurious forms of selection in civilised 

\ nations. 

(Indolence of man, when free from a struggle 

\ for existence, 

jGorilla protecting himself from rain with his 

\ hands. 

Hermaphroditism in fish. 

Eudimentary mammae in male mammals. 
(Changed conditions lessen fertility and cause 
\ ill-health amongst savages. 
JDarkness of skin a protection against the 
\ sun. 

jNote by Professor Huxley on the develop- 
\ ment of the brain in man and apes. 
(Special organs of male parasitic worms for 
\ holding the female. 

Greater variability of male than female; 
direct action of the environment in causing 
differences between the sexes. 

Period of development of protuberances 
on birds' htads determines their trans- 
mission to one or both sexes. 

Causes of excess of male births. 

Proportion of the sexes in the bee family. 
(Excess of males perhaps sometimes deter- 
( mined by selection. 

Bright colours of lowly organised animals. 

Sexual selection amongst spiders. 

Cause of smallness of male spiders. 

Use of phosphorescence of the glow-worm. 

The humming noises of flies. 

Use of bright colours to Hemiptera (bugs). 

Musical apparatus of Homoptera. 

(Development of stridulating apparatus in 
\ Orthoptera. 

(Hermann Miiller on sexual differences of 
\ bees. 

Sounds produced by moths. 

Display of beauty by butterflies. 

(Female butterflies, taking the more active 
\ part in courtship, brighter than their males. 

(Further cases of mimicry in butterflies and 
\ moths. 

(Cause of bright and diversified colours of 
\ caterpillars. 

Corrections to tJie Present Edition. 



Vol. II. 




















359 et seq. 




33 i 


















588 et seq. 



Brush-liko scales of male Mall(.)tu.s. 
|Furtlier facts on courtship of tishcs, and the 
\ spawning of Macropus. 

Dufosse' on the sounds made by fl.slics. 

Belt on a frog protected by bright colouring. 

Further facts on mental powers of snakes. 

Sounds produced by snakes ; the rattlesnake. 

Cond)ats of Chameleons. 

Marshall on protuberances on birds' heads. 
^Further facts on display by the Argus 
\ pheasant. 

Attachment between paired birds. 

Female pigeon rejecting certain males. 
jAlbino birds not finding partners, in a state 
\ of nature. 

Direct action of climate on birds' colours. 
jFurther facts on the ocelli in the Argus 
\ pheasant. 

Display by humming-birds in courtship. 
jCases with pigeons of colour transmitted to 
\ one sex alone. 

I Taste for the beautiful permament enough 
to allow of sexual selection with the lower 
I Horns of sheep originally a masculine 
\ character. 

Castration afiecting horns of animals. 

Prong-horned variety of Cervus vir'jimaiius. 
|Ilelative sizes of male and female whales aud 
\ seals. 

Absence of tusks in male miocene pigs. 

Dobson on sexual differences of bats. 

Eeekson advantage from peculiar colouring. 
|Difterence of comj)lexion in men and women 
\ of an African tribe. 

Speech subsequent to singing, 
|Schopenhauer on importance of courtship to 
\ mankind. 

^Revision of discussion on communal marriages 
\ and promiscuity. 

|Fower of choice of woman in marriage, 
\ amongst savages. 

|Long-continued habit of plucking out hairs 
\ may produce an inherited cfiect. 


Inteoduotion Pages 1-4 



The Evidence of the Descent of Man from some Lower Form. 


Nature 'of the evidence bearing on the origin of man — Homologous 
structures in man and the lower animals — IMiscellaneous points 
of correspondence — Development — Rudimentary structures, 
muscles, sense-organs, hair, bones, reproductive organs, Arc. — 
The bearing of these three great classes of facts on the origin of 
man ........•• ^ 


On the Manner of Development of Man fkom some Lower 


Variability of body and mind in man— Inheritance— Causes of 
variability— Laws of variation the t-ame in man as in the lower 
animals— Direct action of the conditions of life— Etl'ects of the 
increased use and disuse of parts— Arrested development— Re- 
version— Cnrrc luted variation— Rate of Increase — Checks to 
increase— Natural selection- Man the most dominant animal in 
tlie world— Im})ortance of his corporeal structure— Tlie causes 
which have kd to his becoming erect— Consequent clianges of 
structure— Decrease in size of the canine teeth— Increased size 
and altered shape of the skull— Nakedness— Absence of a tail- 
Defenceless condition of man 2G 


Comparison of the Mental Powers of Man and the Lowkr 

The difftrence in mental power between the highest ape and the 
lowest savage, immense— Certain instincts in common— The 
emotions— Curiosity— Imitation— Att(ntion — Memory— Imagi- 
nation— Reason— Progressive improvement- Tools and weapons 

xii Contents. 


used by animals — Abstraction, Sell-consciousness — Language 
— Sense of beauty — Belief in God, spiritual agencies, super- 
stitions ......... 65 



Andials — continued. 

The moral sense — Fundamental proposition-^The qualities of 
social animals — Origin of sociability*— Struggle between opposed 
instincts — Man a social animal — The more endm-ing social in- 
stincts conquer other less persistent instincts — The social virtues 
alone regarded by savages — The self-regarding virtues acquired 
at a later stage of development — The importance of the judg- 
ment of the members of the same community on conduct — 
Transmission of moral tendencies — Summary . . 97 


On the Development of the Intellectual and Moral 
Faculties during Primeval and Civilised Times. 

Advancement of the intellectual powers through natural selec- 
tion — Importance of imitation — Social and moral faculties — 
Their development within the limits of the same tribe — Natural 
selection as affecting civilised nations — Evidence that civilised 
nations were once barbarous . .... 127 


On the Affinities and Genealogy of Man. 

Position of man in the animal series — The natural system genea- 
logical — Adaptive characters of slight value — Various small 
points of resemblance between man and the Quadrumana — 
Bank of man in the natural system — Birthplace and antiquity 
of man — Absence of fossil connecting-links — Lower stages in 
the genealogy of man, as inferred, tirstly from his aiSnities and 
secondly from his structure — Early androgynous condition of 
the Vertebrata — Conclusion . . . . . 14G 

On the Eaces of Man. 

The nature and value of specific characters — Application to the 
races of man — Arguments in favour of, and opposed to, ranking 
the so-called races of man as distinct species — Sub-species — 
Monogenists and polygenists — Convergence of character — 

Contents. xiii 

Numerous points of resemblance in body and mind bet\Ycen the 
most distinct races of man — The state of man when he lirst 
spread over the earth — Each race not descended from a single 
pair — The extinction of races — The formation of races — The 
eftects of crossing — Slight influence of the direct action of the 
conditions of life — Slight or no influence of natural selection — 
Sexual selection ....... 166 



Principles of Sexual Selection. 

Secondary sexual characters — Sexual selection — Manner of action 
— Excess of males — Polygamy — The male alone generally 
modified through sexual selection — Eagerness of the male — 
Variability of the male — Choice exerted by the female— Sexual 
compared with natural selection — Inheritance at corresponding 
periods of life, at corresponding seasons of the year, and as 
limited by sex — Relations between the several forms of inheri- 
tance — Causes why one sex and the young are not modititd 
through sexual selection — Supplement on the proportional num- 
bers of the two sexes throughout the animal kingdom — The 
proportion of the sexes in relation to natural selection . . 207 


Secondary Sexual Characters in the Lower Classes of 
THE Animal Kingdom. 

These characters absent in the lowest classes — Brilliant colours — 
Mollusca — Annelids— Crustacea, secondary sexual characters 
strongly developed ; dimorphism; colour; characters not ac- 
quired before maturity — Spiders, sexual colours of; stridulation 
by the males — Myriapoda 2G0 


Secondary Sexual Characters of Insects. 

Diversified structures possessed by the males for seizing the 
females— Differences between the sexes, of which the mean- 
ing is not understood— Difference in size between the sexes — 
Thysanura — Diptera— llemiptera — Homoptera, musical powers 

xiv Contents. 


possessed by the males alone — Orthoptera, musical instruments 
of the males, nuicli diversified in structure; pugnacity; colours — 
Neuroptera sexual differences in colour — Hymenoptera, pug- 
nacity and colours — Culenptera, colours ; furnished with great 
horns, apparently as an ornament ; battles ; stridulating organs 
generally common to both sexes .... 274 


Insects, continued. — Order Lepidoptera. 

(butterflies and moths.) 

Courtship of butterflies — Battles — Ticking noise — Colours common 
to both sexes, or more brilliant iti the males — Examples — Not 
due to the direct action of the conditions of life — Colours 
adapted for protection — Colours of moths — Distday — Perceptive 
powers of the Lepidoptera — Variability — Causes of the difference 
in colour between the males and females — Mimicry, female 
butterflies more brilliantly coloured than the males — Bright 
colours of caterpillars — Summary and concluding remarks on 
the secondary sexual characters of insects — Birds and insects 
compared ........ 307 


Secondary Sexual Charactters of Fishes, Amphibians, and 

Fishes: Courtship and battles of the males — Larger size of the 
females — Males, bright colours and ornamental appendages; 
other strange characters — Colours and appenilages acquired by 
the males during the breeding-season alone — Fishes with both 
sexes brilliantly coloured — Protective colours — The less con- 
spicuous colours of the female cannot be accounted for on the 
principle of protection — Male fishes building nests, and taking 
charge of the ova and young. Amphibians: Differences in 
structure and colour between the sexes — Vocal organs. Rep- 
tiles : Chelonians — Crocodiles — Snakes, colours m some cases 
protective — Lizards, battles of — Ornamental appendages — 
Strange differences in structure between the sexes — Colours — 
Sexual difterences almost as great as with birds . . 330 


Secondary Sexual Characters of Birds. 

Sexual differences — Law of battle — Special weapons — Vocal 
organs — Instrumental music — Love-antics and dances — Deco- 
rations, permanent and seasonal — Double and single annual 
moults — Display of ornaments by the males . . 358 

Contents. xv 


BiUDS — continued. 


Choice exerted by the female — Length of eourtsliip — Unpaired 
birds — jMental qualities and ta^^te for the beautiful — Preference 
or antipatliy shewn by tlie female for particular males — Vari- 
ability of birds — Variations sometimes abrupt — Laws of varia- 
tion — Formation of ocelli— Gradations of character — Case of 
Peacock, Argus phea.sant, nnd Uro^ticte . . . 404 


Birds — continued. 

Discussion as to why the males alone of some species, and both 
sexes of others are briglilly coloured — On sexually-limited 
inheritance, as applied to various structures and to brightly- 
coloured plumage — Nidification in relation to colour — Loss of 
nuptial plumage during the winter .... 444 


Birds — concluded. 

The immature plumage in relation to the character of the plumage 
in both sexes when adult — Six classes of cases — Sexual diflfer- 
ences between the males of closelj-allied or representative 
species — The female assuming the characters of the male — 
Plumage of the young in relation to the summer and winter 
plumage of the adults — On the increase of beauty in the birds 
of the woi-ld — Protective colouring — Conspicuously-coloured 
birds — Novelty appreciated — Summary of the four chapters on 
birds 463 


Secondary Sexual Characters of Mammals. 

The law of battle — Special weapons, contined to the males — Cause 
of absence of weapons in the female — Weapons common to both 
sexf s, 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 sliewn by either sex in the 
pairing of quadrupeds ...... 500 


Secondary Sexual Characters of Masimals — continued. 

Voice — Remarkable sexual peculiarities in seals — Odour — Develop- 
ment of the hair — Colour of the hair and skin— Anomalous 

xvi Contents. 

case of the female being more ornamented than the male — 
Colour and ornaments due to sexual selection — Colour acquired 
for the sake of protection — Colour, though common to both 
sexes, often due to sexual selection — On the disappearance of 
spots and stripes in adult quadrupeds — On the colours and orna- 
ments of the Quadrumana — Summary . . . 525 

PAET in. 




Secondary Sexual Characters op Man. 

Differences between man and woman — Causes of such differences, 
and of certain characters common to both sexes — Law of battle 
— Differences in mental powers, and voice — On the influence 
of beauty in determining the marriages of mankind — Attention 
paid by savages to ornaments — Their ideas of beauty in woman 
— The tendency to exaggerate each natural peculiarity . 556 


Secondary Sexual Characters 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 civilised and savage nations 
— Conditions favourable to sexual selection during primeval 
times — On the manner of action of sexual selection with man- 
kind — On the women in savage tribes having some power to 
choose theix husbands — Absence of hair on the body, and 
development of the beard — Colour of the skin — Summary . 585 


General Summary and Conclusion. 

Main conclusion that man is descended from some lower form — 
Manner of development — Genealogy of man — Intellectual and 
moral faculties — Sexual selection — Concluding remarks . 603 

Index 620 





The nature of the following work will be best imderstood 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 imphes 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), " pcrsonne, en Europe 
" au moins, n'ose plus soutenir la creation independante et de 
" toutes pieces, des especes," it is manifest that at least a largo 
number of naturalists must admit that species are the modified 
descendants of other species ; and this especially holds good with 
the younger and rising naturalists. The greater number accept 
the agency of natural selection ; though some urge, whether with 
justice the future must decide, that I have greatly overrated its 
importance. Of the older and honoured chiefs in natural science, 
many unfortunately are still opposed to evolution in every 

In consequence of the views now adopted by most naturalists, 
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 • dej^rived of the weighty arguments 
derived from the nature of the affinities which connect together 
whole groups of organisms— their geographical distribution in 
past and present times, and their geological succession. The 
homological structure, embryological development, and rudi- 
mentary organs of a species remain to be considered, whether it 
be man or any other animal, to which our attention may be 
directed ; but these great classes of facts afford, as it appears to 
me, ample and conclusive evidence in favour of the principle of 
gradual evolution. The strong support derived from the other 
arguments should, however, always be kept before the mind. 
. The sole object of this work is to consider, firstly, whether 
man, like every other species, is descended from some pre- 
existing form ; secondly, the manner of his development ; and 
thirdly, the value of the differences between the so-called races 
of man. As I shall confine myself to these jDoints, it will not be 
necessary to describe in detail the differences between the several 
races— an enormous subject which has been fully discussed in 
many valuable works. The high antiquity of man has recently 
been demonstrated by the labours of a host of eminent men, 
beginning with M. Boucher de Perthes ; and this is the indis- 
pensable basis for understanding his origin. I shall, therefore, 
take this conclusion for granted, and may refer my readers to 
the admirable treatises of Sir Charles Lyell, Sir John Lubbock, 
and others. Nor shall I have occasion to do more than to allude 
to the amount of difference between man and the anthropomor- 
phous apes ;.for Prof. Huxley, in the opinion of most competent 
judges, has conclusively shewn that, in every visible character 
man differs less from the higher apes, than these do from 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 draft, appeared to me interesting, I thought that they 
might interest others. It has often and confidently been asserted, 
that man's origin can never be known : but ignorance more 
frequently begets confidence than does knowledge : it is those 
who know little, and not those who know much, who so 
positively assert that this or that problem will never be solved 
by science. The conclusion that man is the co-descendant with 
other species of some ancient, lower, and extinct form, is not in 


any degree new. Lamarck long ago came to this conclusion, 
which has lately been maintained by several eminent naturalists 
and philosophers ; for instance, by Wallace, Hnxley, Lyell, Vogt, 
Lubbock, Biichner, Rolle, &c.,^ and especially by Hackel. Tlj^s 
last naturalist, besides his great work, * Gencrclle Morphologic ' 
(1866), has recently (1868, with a second edit, in 1870), pub- 
lished his * Naturliche Schopfungsgeschichte,' in which he fully 
discusses the genealogy of man. If this work had appeared 
before my essay had been written, I should probably never have 
completed it. Almost all the conclusions at which I have 
arrived I find confirmed by this naturalist, whose knowledge on 
many points is much fuller than mine. Wherever I have added 
any fact or view from Prof. Hiickel's writings, I give his autho- 
rity in the text ; other statements I leave as they originally stood 
in my manuscript, occasionally giving in the foot-notes references 
to his works, as a confirmation of the more doubtful or interesting 

During many years it has seemed to me highly probable that 
sexual selection has played an important part in differentiating 
the races of man ; but in my ' Origin of Species ' (first edition, p. 
199) I contented myself by merely alluding to this belief. "When 
I came to apply this view to man, I found it indispensable to 
treat the whole subject in full detail.^ Consequently the second 
part of the present work, treating of sexual selection, has ex- 
tended to an inordinate length, compared with the first part; 
but this could not be avoided. 

I had intended adding to the present volumes an essay on the 
expression of the various emotions byman and the lower animals. 
My attention was called to this subject many years ago by 
Sir Charles Bell's admirable work. This illustrious anatomist 

' As the works of the first-named JSat.,' Modena, ]8(37, p. 81) a very 

authors are so well known, I need curious paper on rudimentary cha- 

not give the titles; but as those of racters, as bearing on the ori'^in of 

the latter are less well known in man. Another work has (1869) 

England, I will give them : — ' Sechs been published by Dr. Francesco 

Vorlesungen iiber die Darwin'sche Barrago, bearing in Italian the title 

Theorie:' zweite Auflage, 1868, von of "Man, made in the image of God, 

Dr. L. Buchner; translated into " was also made in the image of the 

French under the title 'Conferences "ape." 

sur la Theorie Darwinienne,' 1869. '•^ Prof. Hiickel was the only 

*Der Mensch, im Lichte der Dar- author who, at the time when this 

win'sche Lehre,' 1865, von Dr. F. work first appeared, had di.-,cussed 

Rolle. I will not attempt to give the subject of sexual selection, and 

references to all the authors who had seen its full importance, since 

have taken the same side of the the publication of the 'Origin '; and 

question. Thus G. Canestrini has this he did in a very able manner io 

published (' Annuario della Soc. d. his various works. 


maintains that man is endowed with certain muscles solely for 
the sake of expressing his emotions. As this view is obviously 
opposed to the belief that man is descended from some other and 
l4)wer form, it was necessary for me to consider it. I likewise 
wished to ascertain how far the emotions are expressed in the 
same manner by the different races of man. But owing to. the 
length of the present work, I have thought it better to reser\^e 
my essay for separate publication. 

( 5 ) 

Part I. 


The Evidence of the Descent of Man from some 
Lower Form. 

Nature of the evidence bearing on the origin of man — Homologous 
structures in man and the lower animals — Miscellaneous points of 
correspondence — Development — Rudimentary structures, muscles, sense- 
organs, hair, bones, reproductive organs, &c. — The bearing of these three 
great classes of tacts on the origin of man. 

He who wishes to decide whether man is the modified descendant 
of some. pre-existing form, would probably first enquire whether 
man varies, however slightly, in bodily structure and in mental 
faculties; and if so, whether the variations are transmitted to 
his offspring in accordance with the laws which prevail with tlie 
lower animals. Again, are the variations the result, as far as 
our ignorance permits us to judge, of the same general causes, 
and are they governed by the same general laws, as in the case 
of other organisms ; for instance, by correlation, the inherited 
effects of use and disuse, &c. ? Is man sulycct to similar mal- 
couformations, the result of arrested development, of reduplication 
of parts, &c., and does he display in any of his anomalies rever- 
sion to some former and ancient typo of structure ? It might 
also naturally be enquired whether man, like so many other 
animals, has given rise to varieties and sub-races, differing but 
slightly from each other, or to races differing so much that they 
must be classed as doubtful species? How are such races 
distributed over the world; and how, when crossed, do they 
react on each other in the first and succeeding generations ? 
And so with many other points. 

The enquirer would next come to the important point, 
whether man tends to increase at so rapid a rate, as to lead to 
occasional severe struggles for existence; and consequently to 

6 The Descent of Man. Part I. 

beneficial variations, whether in body or mind, being preserved, 
and injurious ones eliminated. Do the races or species of men, 
whichever term may be applied, encroach on and replace one 
another, so that some finally become extinct ? We shall see that 
all these questions, as indeed is obvious in respect to most of 
them, must be answered in the affirmative, in the same manner 
as with the lower animals. But the several considerations just 
referred to may be conveniently deferred for a time : and we 
will first see how far the bodily structure of man shows traces, 
more or less plain, of his descent from some lower form. In 
succeeding chapters the mental powers of man, in comparison 
w^"th those of the lower animals, will be considered. 

The Bol'dy Structure of Man. — It is notorious that man is 
constructed on the same general type or model as other mam- 
mals. All the bones in his skeleton can be compared with 
corresponding bones in a monkey, bat, or seal. So it is with his 
muscles, nerves, blood-vessels and internal viscera. The brain, 
the most important of all the organs, follows the same law, as 
shewn by Huxley and other anatomists. Bischoff,^ who is a 
hostile witness, admits that every chief fissure and fold in the 
brain of man has its analogy in that of the orang ; but he adds 
that at no period of development do their brains perfectly agree ; 
nor could perfect agreement be expected, for otherwise their 
mental powers would have been the same. Vulpian ^ remarks : 
" Les differences reelles qui existent entre I'encephale de 
" t'homme et celui des singes superieurs, sont bien minimes. II 
" ne faut pas se faire d'illusions a cet egard. L'homme est bien 
" plus pres des singes anthropomorphes par les caracteres 
" anatomiques de son cerveau que ceux-ci ne le sont nou- 
" seulement des autres mammiferes, mais meme de certains 
" quadrumanes, des guenons et des macaques." But it would 
be superfluous here to give further details on the correspondence 
between man and the higher manmials in the structure of the 
brain and all other i^arts 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 shewn. 

Man is liable to receive from the lower animals, and to com- 

1 ' Grosshirnwiadungea des Men- in the Preface to this edition, 
scheu,' 1868, s. 96. The conchisions ^ t Le^_ g^^. i^ Phj-s.' 1866, p. 890, 

of this author, as well as those of as quoted by M. Dally, ' L'Ordre des 

Gratiolet and Aeby, concerning the Primates et leTranslbrmisme,' 1868, 

brain, will be discussed by Prof. p. 29. 
Huxley in the Appendix alluded to 

Chap. I. Hoinological Structures, 7 

mnnicatc to them, certain diseases, as hydrophobia, varioUi, tho 
glanders, syphilis, cholera, herpes, etc. ; ^ and this fact proves tho 
close similarity* of their tissues and blood, both in minntc 
structure and composition, far more plainly than does their 
comparison under the best microscope, or by the aid of the best 
chemical analysis. Monkeys are liable to many of tho same non- 
contagious diseases as we are; thus Eengger,^ who carefully 
observed for a long time the Cthm Azarai 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 apoph^xy, infiannnation 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 
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 north-eastern 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 laughable account of 
their behaviour and strange grimaces. On the following 
morning they were very cross and dismal ; they held their aching 
heads with both hands, and wore a most pitiable expression : 
when beer or wine was offered them, they turned away with 
disgust, but relished the juice of lemons.^ 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 causing 

' Dr. W. Lauder Lindsay has tinct fluids by the same chemical 

treated this subject at some length reagent. 

in the ' Journal of Mental Science,' * ' Naturgescliichte der Siiuge- 

July 1871; and in the 'Edinburgh thiere von Paraguay,' 1830, s. 50. 
Veterinary lieview,' July 1858. ® The same tastes are common to 

* A Rev.ewer has criticised some animals much lower in the 

(' British Quarterly Review,' Oct. scale. Mr. A. Nicols informs me 

1st, 1871, p. 472) what I have here that he kept in Queensland, in Aus- 

said with much severity and con- tralia, three individuals of the 

tempt; but as I do not use the term Fhaseolarctus cinereus ; and that, 

identity, I cannot see that I am without having been taught in any 

greatly in error. There apjiears to way, they acquired a strong taste 

me a strong analogy between the for rum, and for smoking tobacco, 
"same infection or contagion pro- ^ Brehm, 'Thicrleben,' B. i. 1864, 

ducing the same result, or one s. 75, 86. On the Ateles, s. 105. 

closely similar, in two distinct ani- For other analogous statements, see 

mals, and the testing of two dis- s. 25, 107. 

8 The Descent of Man. Part I. 

fatcal effects ; and is plagued by external parasites, all of which 
belong to the same genera or families as those infesting 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 maturation and duration of various 
diseases, to follow lunar periods. His wounds are repaired by 
the same process of healing; and the stumps left after the 
amputation of his limbs, especially during an early embryonic 
period, occasionally possess some power of regeneration, as in 
the lowest animals.'" 

The whole process of that most important function, the 
reproduction of the species, is strikingly the same in all mam- 
mals, from the first act of courtship by the male," 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 tropical countries the difference is not great, for the 
orang is believed not to be adult till the age of from ten to fifteen 
years.'^ Man differs from woman in size, bodily strength, 
hairiness, &c., as well as in mind, in the same manner as do the 

. ^ Dr. W. Lauder Lindsay, ' Edrn- " sagax, hoc mihi certissime pro- 
burgh Vet. Review,' July 1858, " bavit, et curatores ejusdem loci et 
p. 13. " alii e ministris confirmaverunt. 

^ With respect to insects see Dr. " Sir Andrew Smith et Brehm no- 

Laycock, " On a General Law of Vital " tabant idem in Cynocephalo. II- 

Periodicity," ' British Association,' " lustrissimus Cuvier etiam narrat 

1842. Dr. Macculloch, ' Silliman's *' multa de hac re, qua ut opinor, 

North American Journal of Science,' " nihil turpius potest indicari inter 

vol. xvii. p. 305, has seen a dog " omnia hominibus et Quadrumanis 

suffering from tertian ague. Here- " communia. Narrat enim Cyno- 

after I shall return to this subject. " cephalum quendam in furorem in- 

^o I haA-e given the evidence on " cidere aspectu feminarum ali- 

this head in my ' Variation of Ani- " quarum, sed nequaquam accendi 

mals and Plants under Domestica- " tanto furore ab omnibus. Sem- 

tion,' Tol. ii. p. 15, and more could " per eligebat juniores, et dignos- 

be added. " cebat in turba, et advocabat voce 

•^ " Mares e diversis generibus " gestuque." 

" Quadrumanorum sine dubio di- '^ This remark is made with re- 

" gnoscunt feminas humanas a ma- spect to Cynocephalus and the an- 

" ribus. Primum, credo, odoratu, thropomorphous apes by Geoffrey 

" postea aspectu. Mr. Youatt, qui Saint-Hilaire and F. Cuvier, ' Hist, 

*' diu in Hortis Zoologicis (Besti- Nat. des Mammiferes,' tom. 1. 1824. 

" ariis) medicus animalium erat, ^^ Huxley, ' Man's Place in Na- 

" vir in rebus observandis cautus et ture,' 1863, p. 34. 

(^.iiAP. 1. Homological Structures. 9 

two sexes of many mammals. So that the correspondence in 
general structure, in the minute structure of the tissues, in 
chemical composition and in constitution, between man and tlie 
liigher animals, especially the anthropomorphous apes, is ex- 
tremely close. 

Emhnjonlc Dcv^Ioj-mcnt. — Man is developed from an ovule, 
about the 125th of an inch in diameter, which diifcrs in no 
respect from the ovules of other animals. The embryo itself at 
a very early period can hardly be distinguished from that of 
other members of the vertebrate kingdom. At this period the 
arteries run in arch-like branches, as if to carry the blood to 
branchite which are not present in the higher vertebrata, though 
the slits on the sides of the neck still remain (/, g, fig. 1), 
marking their former position. At a somewhat later period, 
when the extremities are developed, " the feet of lizards and 
" mammals," as the illustrious Von Baer remarks, " the wings 
" and feet of birds, no less than the hands and feet of man, all 
" arise from the same fundamental form." It is, says Prof. 
Huxley,^'* " quite in the later stages of development that the 
young human being presents marked differences from the young 
" ape, while the latter departs as much from the dog in its 
" developments, as the man does. Startling as this last assertion 
" may appear to be, it is demonstrably true." 

As some of my readers may never have seen a drawing of an 
embryo, I have given one of man and another of a dog, at about 
the same early stage of development, carefully copied from two 
works of undoubted accuracy.'^ 

After the foregoing statements made by such high autho- 
rities, it would be superfluous on my part to give a number of 
borrowed details, shewing that the embryo of man closely 
resembles that of other mammals. It may, however, be added, 
that the human embryo likewise resembles certain low forms 
when adult in various points of structure. For instance, the 
heart at first exists as a simple pulsating vessel; the excreta 
are voided through a cloacal passage ; and the os coccyx projects 

•* ' Man's Place in Nature,' 1863, magnified, the embryo being twenty- 

p, 67. five days old. The internal viscera 

'^ The human embryo (upper havebeenomitted, and theuterineap- 

fig.) is from Ecker, ' Icones Phys.,' pendages in both drawings removed. 

1851-1859, tab. xxx. fig. 2. This I was directed to these figures by 

embryo was ten lines in length, so Prof. Huxley, from whose woj-k, 

that the drawing is much magnified. ' Man's Place in Nature,' the idea of 

The embryo of the dog is from givmg them was taken. Hiickcl has 

Jiischoff, ' Entwicklungsgeschichte also given analogous drawings in his 

des Humle-Eies,' 1845, tab. xi. fig. ' Schoufuugsgescliichte.' 
42 B This drawing is five time? 


The Descent of Man. 

Part I. 

Fig. 1. 

Upper figure human embryo, from 'Ecker. 
from BischofF. 

Lower figure that of a dog. 

a. Fore-brain, cerebral hemispheres, &c. 
6. Mid-brain, corpora quadrigeniina. 

c. Hind-brain, cerebellum, medulla ob- 

d. Eye. 

e. Ear. 

f. First visceral arch. 

<7. Second visceral arch. 
H. Vertebral columns and muscles 
process of development. 
i Anterior 
K. Posterior 
L. Tail or os coccyx. 


Chap. I. Riidivioits. 1 1 

like a true tail, "extending considerably beyond the rudi- 
" mentary legs.""^ In the embryos of all air-breathing vertebrates, 
certain glands, called the corpora Wolffiana, correspond with, 
and act like the kidneys of mature fishes.''^ Even at a later 
embryonic period, some striking resemblances between man and 
the lower animals may be observed. Bischoflf says that the 
convolutions of the brain in a human foetus at the end of the 
seventh month reach about the same stage of develoj^ment as in 
a baboon when adult.^** The great toe, as Prof. Owen rcmarks,^^ 
" which forms the fulcrum when standing or w\alking, 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 per- 
*' manent condition of this part in the quadrumana." 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 
" immediately below him in the scale : without a doubt in 
" these respects, he is far nearer to apes than the apes are to 
" the dog." 

lludimenU. — This subject, though not intrinsically more 
important than the two last, will for several reasons be treated 
here more fully.-^ Kot one of the higher animals can be named 
which does not bear some part in a rudimentary condition ; and 
man forms no exception to the rule. Eudimentary organs must 
be distinguished from those that are nascent ; though in some 
cases the distinction is not easy. The former are either abso- 
lutely useless, such as the mammae of male quadrupeds, or the 
incisor teeth of ruminants which never cut through the gums ; 
or they are of such slight service to their present possessors, 
that w^e can hardly suppose that they were developed under the 

'* Prof. Wyman in * Proc. of ^^ I had written a rough copy of 

American Acad, of Sciences,' rol. iv. this chapter before reading a valu- 

1860, p. .17, able paper, " Caratteri rudimentali 

*' Owen, ' Anatomy of Verte- in ordine all' origine del iiomo " 

brates,' vol. i. p. 533. (' Annuario della Soc. d. Nat.,' Mo- 

'* 'Die Grosshirnwinduugen des dena, 1867, p. 81), by G. Canestrini, 

Menschen,' 1868, s. 95. to which paper I am considerably 

'^ 'Anatomy of Vertebrates,' vol. indebted. Hiickel has given admir- 

ji. p. 553. able discussions on this whole sub- 

'^° ' Proc. Soc. Nat. Hist.' Boston, ject, under the title of Dysteleology, 

1863, vol. ix. p. 185. in his ' Generelle Morphologic' and 

'* ' Man's Place in Nature,' p. 65. ' Schopfungsgeschichta.' 

1 2 The Descent of Man. Part I. 

conditions wliicli now exist. Organs in this latter state are not 
strictly rudimentary, but they are tending in this direction. 
Nascent organs, on the other hand, though not fully developed, 
are of high service to their possessors, and are capable of further 
development. Rudimentary organs are eminently variable ; and 
this is partly intelligible, as they are useless, or nearly useless, 
and consequently are no longer subjected to natural selection. 
They often become wholly suppressed. When this occurs, they 
are nevertheless liable to occasional reappearance through 
reversion— a circumstance well worthy of attention. 

The chief agents in causing organs to become rudimentary 
seem to have been disuse at that period of life when the organ 
is chiefly used (and this is generally 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 pressure, or 
from becoming in any way less habitually active. Eudiments, 
however, maj occur in one sex of those parts which are normally 
present in the other sex; and such rudiments, as we shall 
hereafter see, have often originated in a way distinct from those 
here referred to. In some cases, organs have been reduced by 
means of natural selection, from having become injurious to the 
species under changed habits of life. The process of reduction 
is probably often aided through the two principles of compensa- 
tion and economy of growth ; but the later stages of reduction, 
after disuse has done all that can fairly be attributed to it, and 
when the saving to be effected by the economy of growth would be 
very small/^ are difl&cult to understand. The final and complete 
suppression of a part, already useless and much reduced in size, 
in which case neither compensation nor economy can come into 
play, is perhaps intelligible by the aid of the hypothesis of 
pangenesis. But as the wliole subject of rudimentary organs 
has been discussed and illustrated in my former works,^^ I need 
here say no more on this head. 

Eudiments of various muscles have been observed in many 
parts of the human body ;^^ and not a few muscles, which are 

^^ Some good criticisms on this Zoolog. 1852, torn, xviii. p. 13) de- 
subject have been given by Messrs. scribes and figures rudiments of 
Murie and Mivart, in 'Transact. what he calls the " muscle pe'dieux 
Zoolog. Soc' 1869, vol. vii. p. 92. de la main," which he says is some- 

2* ' Variation of Animals and times " ipfiniment petit." Another 

Plrnts under Domestication,' vol. ii. muscle, called " le tibial posterieur," 

pp. 317 and 397. See also ' Oj-igin is generally quite absent in the 

of Species,' 5th edit. p. 535, hand, but appears from time to time 

2* For instance M. Richard (' An- in a more or less rudimentary con- 

uales des Sciem'.es Nat.' 3i-d sex'ies, dltion. 

Chap. I. Riidii}ie]its. 13 

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 twitchiDg their skin; and this is 
effected by the panniculns 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 /^A/Zysywa myoides, which is well developed on the 
neck, belongs to this system. Prof. Turner, of Edinburgh, has 
occasionally detected, as he informs me, muscular lasciculi in 
five different situations, namely in the axillae, near the scapulae, 
&c., all of which must be referred to the system of the jianni- 
culus. He has also shewn ^'^ that the muscnlus stemalis or stemalis 
hrutorum, which is not an extension of the rectus abdominal is, 
but is closely allied to the pannicidas, occurred in the proportion 
of about three per cent, in upwards of 600 bodies : he adds, that 
this muscle affords "an excellent illustration of the statement 
" that occasional and rudimentary structures are especially 
" liable to variation in arrangement." 

Some few persons have the power of contracting the super- 
ficial muscles on their scalps ; and these muscles are in a 
variable and partially rudimentary condition. M. A. de Candolle 
has communicated to me a curious instance of the long-continued 
persistence or inheritance of this power, as well as of its unusual 
development. He knows a family, in which one member, the 
present head of the family, could, when a youth, pitch several 
heavy books from his head by the movement of the scalp alone ; 
and he won wagers by performing this feat. His father, uncle, 
grandfather, and his three children possess the same power to 
the same unusual degree. This family became divided eight 
generations ago into two branches; so that the head of the 
above-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 transmission of an 
absolutely useless faculty, probably derived from our remote semi- 
human progenitors; since many monkeys have, and frequently 
use the power, of largely moving their scalps up and down." 

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 

'« Prof. W. Turner, ' Proc. Royal Emotions in Man and Animals,' 
Soc. Edinburgh,' 1866-67, p. 65. 1872, p. 144. 

-^ See my ' Expression of the 

14 The Descent of Man. Part 1 

of the panniculus ; they are also variable in development, or at 
least in function. I have seen one man who could draw the 
whole ear forwards ; other men can draw it upwards ; another 
who could draw it backwards f^ and from what one of these 
persons told me, it is probable that most of us, by often touching 
our ears, and thus directing our attention towards them, could 
recover some power of movement by repeated trials. The power 
of erecting and directing the shell of the ears to the various 
points of the compass, is no doubt of the highest service to 
many animals, as they thus perceive the direction of danger; 
but I have never heard, on sufficient evidence, of a man who 
possessed this power, the one which might be of use to him. 
The whole external shell may be considered a rudiment, together 
with the various folds and prominences (helix and anti-helix, 
tragus and anti-tragus, &c.) which in the lower animals 
strengthen and support the ear when erect, without adding 
much to its weight. Some authors, however, suppose that the 
cartilage of the shell serves to transmit vibrations to the 
acoustic nerve; but Mr. Toynbee,^^ after collecting all the 
known evidence on this head, concludes that the external shell 
is of no distinct use. The ears of the chimpanzee and orang are 
curiously like those of man, and the proper muscles are likewise 
but very slightly developed. "° I am also assured by the keepers in 
the Zoological Gardens that these animals never move or erect 
their ears ; so that they are in an equally rudimentary condition 
with those of man, as far as function is concerned. Why these 
animals, as well as the progenitors of man, should have lost the 
power of erecting their ears, we cannot say. It may be, though 
I am not satisfied with this view, that owing to their arboreal 
habits and great strength they were but little exposed to danger, 
and so during a lengthened period moved their ears but little, 
and thus gradually lost the power of moving them. This 
would be a parallel case with that of those large and heavy 
birds, which, from inhabiting oceanic islands, have not been 
exposed to the attacks of beasts of prey, and have consequently 
lost the power of using their wings for flight. The inability to 
move the ears in man and several apes is, however, partly com- 
pensated by the freedom with which they can move the head in 

2* Canestrini quotes Hyrtl. (' An- lately been experimenting on the 

nuario della Soc. dei Naturalist!, ' function of the shell of the ear, 

Modena, 1867, p. 97) to the same and has come to nearly the same 

effect. conclusion as that given here. 

"^^ ' The Diseases of the Ear,' by ^o p^-of. A. Macalister, ' Annals 

J. Toynbee, F.R.S., 1860, p. 12. and Mag. of Nat. History,' vol, vii.. 

A distinguished physiologist. Prof. 1871, p. 342. 
Preyer, informs me that he had 

Chap. I. 



a horizontal plane, so as to catch sounds from all directions. It 
lias been asserted that the ear of man alone possesses a lobule ; 
but "a rudiment of it is found in the gorilla ;"^^ and, as I hear 
from Prof. Prefer, it is not rarely absent in the negro. 

The celebrated sculptor, Mr. Woolner, informs me of one little 
peculiarity in the external ear, which he has often observed both 
in men and women, and of which he perceived the lull signi- 
ficance. His attention was first called to the subject whilst at 
work on his figure of Puck, to which he had given pointed ears. 
He was thus led to examine the ears of various monkeys, and sub- 
sequently more carefully those of man. The peculiarity consists 
in a little blunt point, projecting from the inwardly folded margin, 
or helix. WHien present, it is developed at birth, and, iiccording 
to Prof. Ludwig Meyer, more frequently in man than in woman. 
Mr. Woolner made an exact model of one such case, and sent me 
the accompanying drawing. (Fig. 2.) 
These points not only project inwards 
towards the centre of the ear, but often 
a little outwards from its plane, so as 
to be visible when the head is viewed 
from directly in front or behind. They 
are variable in size, and somewhat in 
position, standing either a little higher 
or lower; and they sometimes occur 
on one ear and not on the other. They 
are not confined to mankind, for I ob- 
served a case in one of the spider- 
monkeys (Ateles beehfhufh) in our 
Zoological Gardens; and Dr. E. Pay 
Lankester informs me of another case 
in a chimpanzee in the gardens at 
Hamburg. The helix obviously con- 
sists of the extreme margin of the ear folded inwards; and 
this folding appears to be in some manner connected with the 
whole external ear being permanently pressed backwards. In 
many monkeys, which do not stand high in the order, as baboons 
and some species of macacus,^^ the upper portion of the ear is 
slightly pointed, and the margin is not at all folded inwards ; 
but if the margin were to be thus folded, a slight point would 
necessarily project inwards towards the centre, and probably a 
little outwards from the plane of the ear ; and this I believe to 

^* Mr. St. George Mivart, ' Ele- Lemuroidea, in Messrs. Murie and 

mentary Anatomy,' 1873, p. 396. ]\Iivart's excellent paper in 'Tran« 

32 See also some remarks, and sact. Zoolog. Soc' vol. vii. 1869, pp. 

the drawings of the ears of the 6 and 90. 

Fig 2. Unman Ear. morielled 

and drawn by Mr. Woolner. 

a. The projecting point. 

1 6 TJie Descent of Man. Part I. 

be their origin in many cases. On the other hand, Prof. L. Meyer, 
in an able paper recently pubhshed,^ maintains that the whole 
case is one of mere variability ; and that the projections are not 
real ones, but are due to the internal cartilage on each side of 
the points not having been fully developed. I am quite ready 
to admit that this is the correct explanation in many instances, 
as in those figured by Prof. Meyer, in which there are several 
minute points, or the whole margin is sinuous. I have myself 
seen, through the kindness of Dr. L. Down, the ear of a micro- 
cephalous idiot, on which there is a projection on the 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 wliich the upper margin is not at all folded inwards, 
but is pointed, so that it closely resembles the pointed ear of an 
ordinary quadruped in outline. In one of these cases, which was 
that of a young child, the father compared the ear with the 
drawing which I have given^^ of the ear of a monkey, the 
Cynopithecus rdger, and says that their outlines are closely 
similar. If, in these two cases, the margin had been folded 
inwards in the normal manner, an inward projection must have 
been formed. I may add that in two other cases the outline still 
remains somewhat pointed, although the margin of the upper 
part of the ear is normally folded inwards — in one of them, 
however, very narrowly. The following woodcut (No. 3) is an 
accurate copy of a photograph of the foetus of an 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 resemblance to that of man. It is 
evident that the folding over of the tip of such an ear, unless it 
changed greatly during its further development, would give rise 
to a point projecting inwards. On the whole, it still seems to 

'^ Ueber das Darwin'sche Spitzohr, ^* 'The Expression of the Emo- 

Archiv fiir Path. Anat. und Phys. tions,' p. 136. 
1871, p. 485. 

Chap. I. 



me probable that the points in question are in some cases, both 
in man and apes, vestiges of a former condition. 

Fig 3. Foetus of an OranR. Fxact copy of a photograph, shewing the form of 
the ear at this early age. 

The nictitating membrane, or third eyelid, with its accessory 
mnscles and other structures, is especially well developed in 
birds, and is of much functional importance to them, as it can 
be rapidly drawn across the whole eye-ball. It is found in some 
reptiles and amphibians, and in certain fishes, as in sharks. It 
is fairly well developed in the two lower divisions of the mam- 
malian series, namely, in the monotreraata and marsupials, and 
in some few of the higher mammals, as in the walrus. But in 
man, the quadruraana, 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 finding their 
prey; to others, again, as the wild boar, for both purposes 
combined. But the sense of smell is of extremely slight service, 
if any, even to the dark coloured races of men, in whom it is 

" Miillev's 'Elements of Physi- 
ology,* Eng. translat., 1842. vol. ii. 
p. 1117. Owen, * Anatomy of Verte- 
brates,' vol. iii. p. 260; ibid, on 
the Walrus, * Proo. Zoolog. Soc' 
November 8th, 1854. See also R. 

Knox, 'Great Artists and Anato- 
mists,' p. 106. This rudiment ap- 
parently is somewhat larger in 
Negroes and Australians than in 
Europeans, see Carl Vogt, ' Lectures 
on Man,' Eng. translat. p. 129. 

1 8 The Descent of Man. Part I. 

much more highly deyeloped than in the white and civilised 
races."^ Nevertheless it does not warn them of danger, nor guide 
them to their food ; nor does it prevent the Esquimaux from 
sleeping in the most fetid atmosphere, nor many savages from 
eating half-putrid meat. In Europeans the power differs greatly 
in different individuals, as I am assured by an eminent naturalist 
who possesses this sense highly developed, and who has at- 
tended to the subject. Those who believe in the principle 
of gradual evolution, will not readily admit that the sense of 
smell in its present state was originally acquired by man, as 
he now exists. He inherits the power in an enfeebled and 
so far rudimentary condition, from some early progenitor, to 
whom it was highly serviceable, and by whom it was con- 
tinually used. In those animals which have this sense lughly 
developed, such as dogs and horses, the recollection of persons 
and of places is strongly associated with their odour ; and we can 
thus perhaps understand how it is, as Dr. Maudsley has truly 
remarked,^^ that the sense of smell in man " is singularly effective 
" in recalHng 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'mau, and fine down on that 
of the woman. The different races differ much in hairiness ; and 
in the individuals of the same race the hairs are highly variable, 
not only in abundance, but likewise in position : thus in some 
Europeans the shoulders are quite naked, whilst in others they 
bear thick tufts of hair.^^ There can be little doubt that the 
hairs thus scattered over the body are the rudiments of the 
uniform hairy coat of the lower animals. This view is rendered 
all the more probable, as it is known that fine, short, and pale- 
coloured hairs on the limbs and other parts of the body, occasion- 

^^ The account given by Humboldt olfactory region, as well as of the 
of the power of smell possessed by skin of the body. I have, therefore, 
the natives of South America is well spoken in the text of the dark- 
known, and has been confirmed by coloured races having a finer sense 
others. M. Hoiizeau (' Etudes sur of smell than the white races. See 
les Faculte's Mentales,' &c., torn. i. his paper, ' Medico-Chirurgical Tran- 
1872, p. 91) asserts that he re- sactions,' London, vol. liii., 1870, 
peatedly made experiments, and p. 276. 

proved that Negroes and Indians ^^ ' The Physiology and Pathology 

could recognise persons in the dark of Mind,' 2nd edit. 1868, p. 134-. 

by their odour. Dr. W. Ogle has ^s Eschricht, Ueber die Kichtung 

made some curious observations on der Haare am menschlichen Korper, 

the connection between the power 'Miiller's Archivfur Anat.und Phys.' 

of smell and the colouring matter 1837, s. 47. I shall often have to 

of the mucous membrane of the refer to this very curious paper. 

Chap. I. Rudiments. 19 

ally become developed into " thickset, long, and rather coarse 
" dark hairs," when abnormally nourished near old-standing 
inflamed surfaccs.^^ 

I am informed by Sir James Paget that often several members 
of a family have a few hairs in their eyebrows much longer than 
the others; so that even this slight peculiarity seems to be 
inherited. These hairs, too, seem to have their repiesentatives ; 
for in the chimpanzee, and in certain sjDecies of Macacus, there 
are scattered hairs of considerable length rising from the naked 
skin above the eyes, and corresponding to our eyebrows ; similar 
long hairs project from the hairy covering of the superciliary 
ridges in some baboons. 

The fine wool-like hair, or so-called lanugo, with which the 
human foetus during the sixth month is thickly covered, ofifers a 
more curious case. It is first developed, daring the fifth month, 
on the eyebrows and face, and especially round the mouth, 
where it is much longer than that on the head, A moustache 
of this kind was observed by Eschriclit^° on a female foetus ; but 
this is not so surprising a circumstance as it may at first appear, 
for the two sexes generally resemble each other in all external 
characters during an early period of growth. The direction and 
arrangement of the hairs on all parts of the 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 
tliickly clothed ; but it is a significant fact that the palms of the 
hands and the soles of the feet are quite naked, like the inferior 
surfaces of all four extremities in most of the lower animals. As 
this can hardly be an accidental coincidence, the woolly cover- 
ing of the foetus probably repres(;nts the first permanent coat of 
hair in those mammals which are born hairy. Three or four 
cases have been recorded of persons born with their whole bodies 
and faces thickly covered with fine long hairs ; and this strange 
condition is strongly inherited, and is correlated with an abnor- 
mal condition of the teeth.'*^ Prof. Alex. Brandt informs me that 
he has compared the hair from the face of a man thus charac- 
terised, aged thirty-five, with the lanugo of a foetus, and finds it 
quite similar in texture ; therefore, as he remarks, the case may 
be attributed to an arrest of development in the hair, together 
with its continued growth. Many delicate children, as I have 

^' Paget, 'Lectures on Sui'gical has recently sent me an additional 

Pathology,' 1853, vol. i. p. 71. case of a father and son, born in 

■*° Eschrichi, ibid. s. 40, 47. Piussia, with these peculi;irities. I 

** See my ' Variation of Animals have received drawings of both from 

and Plants under Domestication,' Paris. 

vol. ii. p. 327. Prof. Alex. Brandt 

20 The Descent of Man. Part I. 

been assured by a surgeon to a hospital for children, have their 
backs covered by rather long silky hairs ; and such cases pro- 
bably come under the same head. 

It appears as if the posterior molar or wisdom-teeth were 
tending to become rudimentary in the more civilised races of 
man. These teeth are rather smaller than the other molars, as 
is likewise the case with the corresponding teeth in the chim- 
panzee and orang ; and they have only two separate fangs. 
They do not cut through the gums till about the seventeenth 
year, and I have been assured that they are much more liable to 
decay, and are earlier lost than the other teeth ; but this is denied 
by some eminent dentists. They are also much more liable to 
vary, both in structure and in the period of their development, 
than the other teeth.'*'^ 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 civilised,^* and this shortening may, 
I presume, be attributed to civilised men habitually feeding on 
soft, cooked food, and thus using their jaws less. I am informed 
by Mr. Brace that it is becoming quite a common practice in the 
United States to remove some of the molar teeth of children, as 
the jaw does not grow large enough for the perfect development 
of the normal number.^^ 

With respect to the alimentary canal, I have met with an 
account of only a single rudiment, namely the vermiform append- 
age of the caecum. The caecum is a branch or diverticulum of 
the intestine, ending in a cul-de-sac, and is extremely long in 
many of the lower vegetable-feeding mammals. In the marsupial 
koala it is actually more than thrice as long as the whole body.^^ 
It is sometimes produced into a long gradually-tapering point, 
and is sometimes constricted in parts. It appears as if, in con- 
sequence of changed diet or habits, the caecum had become much 

42 Dr. Webb, 'Teeth in Man and from Florence, that he has lately 

the Anthropoid Apes,' as quoted by been studying the last molar teeth 

Di*. C. Carter Blake in ' Anthropo- in the different races of man, and 

logical Review,' July 1867, p. 299. has come to the same conclusion as 

■*3 Owen, ' Anatomy of Verte- that given in my text, viz., that in 

brates,' vol. iii. pp. 320, 321, and the higher or civilised races they 

325. are on the road towards atrophy or 

** 'On the Primitive Form of the elimination. 

Skull,' Eng. translat. in 'Anthropo- ^^ Owen, 'Anatomy of Verte- 

logical Review,' Oct. 1868, p. 426. brates,' vol. iii. pp. 416, 434, 441. 

^= Prof. Montegazza writes to me 

Chap. I. Rudiments. 21 

shortened in various animals, the vermiform appendage being 
left as a rudiment of the shortened part. That this appendage 
is a rudiment, we may infer from its small size, and from the 
evidence which Prof. Canestrini*^ has collected of its variability 
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 
caecum, and is commonly from four to five inches in length, 
being only about the third of an inch in diameter. Kot only is 
it useless, but it is sometimes the cause of death, of which fact 
I have lately heard two instances : this is due to small hard 
bodies, such as seeds, entering the passage, and causing inflam- 

In some of the lower Quadrumana, in the Lemurida3 and 
Carnivora, as well as in many marsupials, there is a passage near 
the lower end of the humerus, called the supra-condyloid fora- 
men, through which the great nerve of the fore limb and often 
the great artery pass. Now in the humerus of man, there is 
generally a trace of this passage, which is sometimes fairly well 
developed, being formed by a depending hook -like process of 
bone, completed by a band of ligament. Dr. Struthers,''^ who has 
closely attended to the subject, has now shewn that this 
peculiarity is sometimes inherited, as it has occurred in a father, 
and in no less than four out of his seven children. When pre- 
sent, the great nerve invariably passes through it; and this 
clearly indicates that it is the homologue and rudiment of the 
supra-condyloid foramen of the lower animals. Prof. Turner 
estimates, as he informs me, that it occurs in about one per cent, 
of recent skeletons. But if the occasional development of this 
structure in man is, as seems probable, due to reversion, it is a 
return to a very ancient state of things, because in the higher 
Quadrumana it is absent. 

There is another foramen or perforation in the humerus, 

<^ 'Annuario della Soc, d. Nat' Feb. 15, 1873, and another im- 

Modena, 1867, p. 94. portant paper, ibid., Jan. 24, 1863, 

■"8 M. C. Martins (*' De I'Unite p. 83. Dr. Knox, as I am informed, 

Orgauique," in ' Revue des Deux was the first anatomist who drew 

Moudes,' June 15, 1862, p. 16), and attention to this peculiar structure 

Hackel (' Generelle Morphologic,' in man ; see his ' Great Artists and 

B. ii. s. 278), have both remarked Anatomists,' p. 63. See also an im- 

on the singular fact of this rudi- portant memoir on this process by 

ment sometimes causing death. Dr. Gruber, in the ' Bulletin de 

** With respect to inheritance, I'Acad. Imp. de St. Pe'tersbourg,' 

see Dr. Struthers in the ' Lancet,' tom. xii. 1867, p. 448. 

22 The Descent of Man. Part I. 

occasionally present in man, which may be called the inter- 
condyloid. This occurs, but not constantly, in various anthro- 
poid 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 ' Cimetiere du 
" Sud,' at Paris ; and in the Grotto of Orrony, the contents of 
" which are referred to the Bronze period, as many as eight 
" humeri out of thirty-two were perforated ; but this extraordi- 
" nary proportion, he thinks, might be due to the cavern having 
" been a sort of ' family vault.' Again, M. Dupont found thirty 
" per cent, of perforated bones in the caves of the Valley of the 
'' Lesse, belonging to the Eeindeer period ; whilst M. Leguay, in 
" a sort of dolmen at Argenteuil, observed twenty -five per cent, 
"to be perforated; and M. Pruner-Bey found twenty-six per 
" cent, in the same condition in bones from Yaureal. Nor should 
''it be left unnoticed that M. Pruner-Bey states that this con- 
'* dition is common in G-uanche 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 vertebrae 
hereafter to be described, though functionless as a tail, plainly 
represent this part in other vertebrate animals. At an early 
embryonic period it is free, and projects beyond the lower 
extremities ; as may be seen in the drawing (Fig. 1.) of a human 
embryo. Even after birth it has been known, in certain rare 
and anomalous cases,^^ to form a small external rudiment of a 
tail. The os coccyx is short, usually including only four 
vertebrEe, all anchylosed together: and these are in a rudi- 

*" Mr. St. George Mivart, ' Trans- ^2 Quatrefages has lately collected 

act. Phil. Soc' 1867, p. 310. the evidence on this subject. ' Revue 

" "On the Caves of Gibraltar," des Cours Scientifiques,' 1867-1868, 

'Transact. Internat. Congress of p. 625. In 1840 Fleischmann ex- 

Prehist. Arch.' Third Session, 1869, hibited a human foetus bearing a 

p. 159. Prof. Wyman has lately free tail, which, as is not always the 

shewn (Fourth Annual Report, Pea- case, included vertebral bodies ; and 

body Museum, 1871, p. 20), that this this tail was critically examined by 

perforation is present in thirty-one the many anatomists present at the 

per cent, of some human remains meeting of naturalists at Erlangen 

from ancient mounds in the Western (see Marshall in Niederltindischen 

United States, and in Florida. It Archivfiir Zoologie, Decemberl871). 
frequently occurs in the negro. 

Chap. I. Rudimejits. 23 

mentary condition, for they consist, with the exception of tlie 
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 exj^ressly described by Theile as a rudimentary 
repetition of the extensor of the tail, a muscle which is so 
largely developed in many mammals. 

The spinal cord in man extends only as far downwards as the 
last dorsal or first lumbar vertebra; but a thread-like struc- 
ture {i\\Q. filum ttrminah-^ runs down the axis of the sacral part 
of the spinal canal, and even along the back of the coccygeal 
bones. The upper part of this filament, as Prof. Turner 
informs me, is undoubtedly homologous with the spinal cord ; 
but the lower part apparently consists merely of the pia mater, 
or vascular investing membrane. Even in this case the os 
coccyx may be said to possess a veslige of so important a 
structure as the spinal cord, though no longer enclosed within 
a bony canal. The following fact, for which I am also in- 
debted to Prof. Turner, shews how closely the os coccyx corre- 
sponds with the true tail in the lower animals : Luschka has 
recently discovered at the extremity of the coccygeal bones a 
very peculiar convoluted body, which is continuous with the 
middle sacral artery ; and this discovery led Krause and Meyer 
to examine the tail of a monkey (Macacus), and of a cat, in both 
of which they found a similarly convoluted body, though not at 
the extremity. 

The reproductive system offers various rudimentary struc- 
tures; but these differ in one important respect from the 
foregoing cases. Here we are not concerned with the vestige of 
a part which does not belong to the species in an efficient state, 
but with a part efficient in the one sex, and represented in the 
other by a mere rudiment. Nevertheless, the occurrence of 
such rudiments is as difficult to explain, on the belief of the 
separate creation of each species, as in the foregoing cases. 
Hereafter I shall have to recur to these rudiments, and shall 
shew that their presence generally depends merely on inheri- 
tance, that is, on parts acquired by one sex having been 
partially transmitted to the other. I will in this place only give 
somQ instances of such rudiments. It is well known that in the 
males of all mammals, including man,, rudimentary mammae 
exist. These in several instances have become well developed, 
and have yielded a copious supply of milk. Their essential 
identity in the two sexes is likewise shewn by their occasional 
sympathetic enlargement in both during an attack of the 

" Owen, 'On the Nature of Limbs,' 1849, p. 114. 

24 The Desceiit of Mmi. Paet I. 

measles. The vesicula prostatlca, which has been observed in 
many male mammals, is now universally acknowledged to bo 
the homologne of the female uterus, together with the con- 
nected passage. It is impossible to read Leuckart's able 
de'scription of this organ, and his reasoning, without admitting 
the justness of his conclusion. This is especially clear in the 
case of those mammals in which the true female uterus 
bifurcates, for in the males of these the vesicula likewise 
bifurcates.^* Some other rudimentary structui-es belonging to 
the reproductive system might have been here adduced. ^^ 

The bearing of the three great classes of facts now given is 
unmistakeable. But it would be superfluous fully to recapitulate 
the line of argument given in detail in my ' Origin of Species.' 
The homological construction of the whole frame in the members 
of the same class is intelligible, if we admit their descent from 
a common progenitor, together with their subsequent adaptation 
to diversified conditions. On any other view, the similarity of 
pattern between the hand of a man or monkey, the foot of a 
horse, the flipper of a seal, the wing of a bat, &c., is utterly 
inexplicable,^^ It is no scientific explanation to assert that they 
have all been formed on the same ideal plan. With respect to 
development, we can clearly understand, cm the principle of 

'* Leuckart, in Todd's 'Cyclop. words) a mere metaphysical prin- 

vf Anat.' 1849-52, vol. iv. p. 1415. ciple, namely, the preservation "in 

In man this organ is only from " its integrity of the mammalian 

three to six lines in length, but, " nature of the animal." In only a 

like so many other rudimentary few cases does he discuss rudiments, 

parts, it is variable in development and then only those parts which are 

as well a^ in other characters. partially rudimentary, such as the 

5^ See, on this subject, Owen, little hoofs of the pig and ox, which 

'Anatomy of Vertebrates,' vol. iii. do not touch the ground; these he 

pp. 675, 676, 706. shews clearly to be of service to the 

^s Prof. Bianconi, in a recently animal. It is unfortunate that he 
published work, illustrated by ad- did not consider such cases as the 
mirable engravings (' La The'orie minute teeth, which never cut 
Darwiuienne et la creation dite in- through the jaw in the ox, or the 
de'pendante,' 1874), endeavours to mammae of male quadrupeds, or the 
show that homological structures, in wings of certain beetles, existing 
the above and other cases, can be under the soldered wing-covers, or 
fully explained on mechanical prin- the A'estiges of the pistil and stamens 
ciples, in accordance with their uses, in various flowers, and man}f other 
No one has shewn so well, how ad- such cases. Although 1 greatly 
mirably such structures are adapted admire Prof. Bianconi's work, yet 
for their final purpose; and this the belief now held by most natural- 
adaptation can, as I believe, be ists seems to me left unshaken, 
explained through natural selection. that homological structures are in- 
In considering the wing of a'bat, he explicable on the principle of mere 
brings forward (p. 218) what appears adaptation. 
to me (to use Auguste Comte's 

Chap. I. Rjidimetits. 2$ 

■variations supervening at a rather late embryonic period, and 
being inherited at a corresponding period, how it is 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, &c., can at first 
hardly be distinguished from each other. In order to understand 
the existence of rudimentary organs, we have only to suppose 
that a former progenitor possessed the parts in question in a 
perfect state, and that under changed habits of life thoy became 
greatly reduced, either from simple disuse, or through the natural 
selection of those individuals which were least encumbered with 
a superfluous part, aided by the other means previously in- 

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 animals around us, is a mere snare 
laid to entrap our judgment. This conclusion is greatly 
strengthened, if we look to the members of the whole animal 
series, and consider the evidence derived from their affinities 
or classification, their geographical distribution and geolo- 
gical succession. It is only our natural prejudice, and that 
arrogance which made our forefathers declare that they were 
descended from demi-gods, which leads us to demur to this 
conclusion. But the time will before long come, when it will be 
thought wonderful that naturalists, who were well acquainted 
with the comparative structure and development of man, and 
other mammals, should have believed that each was the work 
of a separate act of creation. 

26 The Descent of Man. Part L 


On the Manner of Development of Man from some 
Lower Form. 

Variability of body and mind in man — Inheritance — Causes of variability 
— Laws of variation the same in man as in the lower animals — Direct 
action of the conditions of life — Effects of the increased use and disuse 
of parts — Arrested development — Reversion — Correlated variation — 
Rate of increase — Checks to increase — Natural selection — Man the most 
dominant animal in the world — Importance of his corporeal structure — 
The causes which have led to his becoming erect — Consequent changes 
of structure — Decrease in size of the canine teeth — Increased size and 
altered shape of the skull — Nakedness — Absence of a tail — Defenceless 
condition of man. 

It is manifest that man is now subject to much yariability. 
No two individuals of the same race are quite alike. We may 
compare millions of faces, and each will be distinct. There is 
an equally great amount of diversity in the proportions and 
dimensions of the various parts of the body ; the length of the 
legs being one of the most variable points.^ Although in some 
quarters of the world an elongated skull, and in other quarters 
a short skull prevails, yet there is great diversity of shape even 
within the limits of the same race, as with the aborigines of 
America and South Australia — the latter a race *' probably as 
" pure and homogeneous in blood, customs, and language as any 
" in existence" — and even with the inhabitants of so confined 
an area as the Sandwich Islands. ^ An eminent dentist assures 
me that there is nearly as much diversity in the teeth as in the 
features. The chief arteries so frequently run in abnormal 
courses, that it has been found useful for surgical purposes to 
calculate from 1040 corpses how often each course prevails.' 
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. 

* ' Investigations in Military and Huxley, in Lyell's ' Antiquity of 
Anthropolog. Statistics of American Man,' 1863,. p. 87. On the Sand- 
Soldiers,' by B. A. Gould, 1869, p. wich Islanders, Prof. J. Wyman, 
256. ' Observations on Crania,' Boston, 

2 With respect to the "Cranial 1868, p. 18. 

forms of the American aborigines," ' 'Anatomy of the Arteries,' by 

see Dr. Aitken Meigs in ' Proc. R. Quain. Preface, vol. i. 1844. 

Acad. Nat. Sci.' Philadelphia, May, * 'Transact. Royal Soc. Edin- 

1868. On the Australians, see burgh,' vol. xxiv. pp. 175, 189. 

Chap. II. Maimer of Development. 2^ 

He adds, that the power of performing the appropriate move- 
ments must have been modified in accordance with the several 
deviations. Mr. J. Wood has recorded^ the occurrence of 295 
muscular variations in thirty-six subjects, and in another set of 
the same number no less than 558 variations, those occurring on 
both sides of the body being only reckoned as one. In the last 
set, not one body out of the thirty-six was " found totally 
" wanting in departures from the standard, descriptions of the 
" muscular sj^stem 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 jpalmaru accessor ins. 

The famous old anatomist, Wolff,'^ insists that the internal 
viscera are more variable than the external parts : Nulla jparti- 
cala est qux non aliter et aliter in aliis se habeat hominibus. He 
has even written a treatise on the choice of typical examples of 
the viscera for representation. A discussion on the beau-ideal 
of the liver, lungs, kidneys, &c., as of the human face divine, 
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. All who have 
had charge of menageries admit this fact, and we see it plainly 
in our dogs and other domestic animals. Brehm especially 
insists that each individual monkey of those which he kept tame 
in Africa had its own peculiar disposition and temper ; he men- 
tions one baboon remarkable for its high intelligence ; and the 
keepers in the Zoological Gardens pointed out to me a monkey, 
belonging to the New World division, equally remarkable for 
intelligence. Eengger, also, insists on the diversity in the 
various mental characters of the monkeys of the same species 
which he kept in Paraguay ; and this diversity, as he adds, is 
partly innate, and partly the result of the manner in which they 
have been treated or educated.^ 

I have elsewhere^ so fully discussed the subject of Inheritance, 
that I need here add hardly anything. A greater number of 

5 'Pioc. Royal Soc' 1867, p. » Brehm, ' Thierleben,' B. i. s. 

544 ; also ] 868, pp. 48.'3, 524. There 58, 87. Kengger, ' Saugethiere von 

is a previous paper, 1866, p. 229. Paraguay,' s. 57. 

* ' Proc. R. Irish Academy,' vol. ' ' Variation of Animals an^ 

X. 1868, p. 141. Plants under Domestication,' vol 

^ 'Act. Acad. St. Petersburg,* ii. chap. xii. 
1778, part ii. p. 217 

28 The Descent of Man. Part L 

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 animals; though the facts are 
copious enough with respect to the latter. So in regard to 
mental qualities, their transmission is manifest in our dogs, 
horses, and other domestic animals. Besides special tastes and 
habits, general intelligence, courage, bad and good temper, &c., 
are certainly transmitted. With man we see similar facts in 
almost every family; and we now know, through the admirable 
labours of Mr. Galton,^°that genius which implies a wonderfully 
complex combination of high faculties, tends to be inherited; 
and, on the other hand, it is too certain that insanity and deteri- 
orated mental powers likewise run in families. 

With respect to the causes of variability, we are in all cases 
very ignorant; but we can see that in man as in the lower 
animals, they stand in some relation to the conditions to which 
each species has been exposed, during several generations. 
Domesticated animals vary more than those in a state of nature ; 
and this is apparently due to the diversified and changing nature 
of the conditions to which they have been subjected. In this 
respect the different races of man resemble domesticated animals, 
and so do the individuals of the same race, when inhabiting a 
very wide area, like that of America. We see the influence of 
diversified conditions in the more civilised nations; for the 
members belonging to different grades of rank, and following 
different occupations, present a greater range of character than 
do the members of barbarous nations. But the uniformity of 
savages has often been exaggerated, and in some cases can hardly 
be said to exist.^^ It is, nevertheless, an error to speak of man, 
even if we look only to the conditions to which he has been 
exposed, as " far more domesticated "^^ 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 

'" * Hereditary Genius : an In- " man had an oval visage with fine 

quiry into its Laws and Conse- " features, and another was quite 

quences,' 1869. " Mongolian in breadth and pro- 

'* Mr. Bates remarks (' The Natu- " minence of cheek, spread of nos- 

ralist on the Amazons,' 1863, vol. ii. " trils, and obliquity of eyes." 

p. 159), with respect to the Indians ^^ Blumenbach, 'Treatises on An- 

of the same South American tribe, thropolog.' Eng. translat., 1865, p. 

*' no two of them were at all similar 205. 
" in the shape of the head ; one 

Chap. II. Manner of Developmefit 29 

completely siibjugcated by other men, as that certain individuals 
should be preserved, and thus unconsciously selected, from some- 
how excelling in utility to their masters. Nor have certain 
male and female individuals been intentionally picked out and 
matched, except in the well-known case of the Prussian grena- 
diers ; and in this case man obeyed, as miglit have been ex- 
pected, the law of methodical selection ; for it is asserted that 
many tall men were reared in the villages inhabited by the 
grenadiers and their tall wives. In Sparta, also, a form of selec- 
tion was followed, for it was enacted that all children should be 
examined shortly after birth ; the well-formed and vigorous 
being preserved, the others left to perish.^' 

If we consider all the races of man as forming a single species, 
his range is enormous ; but some separate races, as the Americans 
and Polynesians, have very wide ranges. It is a well-known 
law that widely-ranging species are much more variable than 
species with restricted ranges ; and the variability of man may 
with more truth be compared with that of widely-ranging species, 
than with that of domesticated animals. 

Not only does variability appear to 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 detail by Godron and 

^' Mitford's 'History of Greece,' vigour of their children. The Gre- 

vol. i. p. 282. It appears also from cian poet, Theognis, who lived 550 

a passage in Xenophon's ' Memora- B.C., clearly saw how important 

bilia,' B. ii. 4 (to which my atten- selection, if carefully applied, would 

tion has been called by the Rev. be for the improvement of mankind. 

J. N. Hoare), that it was a well He saw, likewise, that wealth often 

recognised principle with the Greeks, checks the proper action of sexual 

that men ought to select their wives selection. He thus writes : 
with a view to the health and 

" With kine and horses, Kurnus ! we proceed 
By reasonable rules, and choose a breed 
For profit and increase, at any price ; 
Of a sound stock, without detect 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 oflspring with the proudest race : 
Thus everytliing 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 plain, 
And to lament the consequence is vain." 
(The Works of J. Hookham Frere, vol. ii. 1872, p. 334.) 

30 TJie Descent of Mmi. Part I, 

Quatrefages, that I need here only refer to their works.^^ Mon- 
strosities, which graduate into slight variations, are likewise so 
similar in man and the lower animals, that the same classification 
and the same terms can be used for both, as has been shewn by 
Isidore Geoffroy St.-Hilaire.'^ In my work on the yariation of 
domestic animals, I have attemjDted to arrange in a rude fashion 
the laws of variation under the following heads : — The direct and 
definite action of changed conditions, as exhibited by all or nearly 
all the individuals of the same species, varying in the same manner 
under the same circumstances. The effects of the long-continued 
use or disuse of parts. The cohesion of homologous parts. The 
variability of multiple parts. Compenpation 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 con- 
siderable length. 

The direct and definite action of changed conditions. — This is a 
most perplexing subject. It cannot be denied that changed con- 
ditions produce some, and occasionally a considerable effect, on 
organisms of all kinds ; and it seems at first probable that if 
sufficient time were allowed this would be the invariable result. 
But 1 have failed to obtain clear evidence in favour of this con- 
clusion ; and valid reasons may be urged on the other side, at 
least as far as the innumerable structures are concerned, which 
are adapted for special ends. There can, however, be no doubt 
that changed conditions induce an almost indefinite amount of 
fluctuating variability, by which the whole organisation is rend- 
ered in some degree plastic. 

In the United States, above 1,000,000 soldiers, who served in 
the late war, were measured, and the States in which they were 

^'* Godron, 'De I'Espece,' 1859, '^ I have fully discussed these 

torn. ii. livre 3. Quatrefages, ' Unite laws in my * Variation of Animals 

de I'Espece Humaine,' 1861. Also and Plants under Domestication,' 

Lectures on Anthropology, given in vol. ii. chap. xxii. and xxiii. M. J. 

the ' Revue des Cours Scientifiques,' P. Durand has lately (1868) pub- 

1886-1868. lished a valuable essay ' De I'ln- 

'* ' Hist. Gen. et Part, des Ano- fluence des Milieux,' &c. He lays 

malies de I'Organisation,' in three much stress, in the case of plants, on 

volumes, tom. i. 1832. the nature of the soil. Manner of Dcvelopiuciit. 31 

born and reared were recorded.'^ From this astonishing number 
of observations it is proved tlmt local influences of some kind 
act directly on stature ; and we further learn that " the State 
" where the physical growth has in great measure taken place, 
" and the State of birth, which indicates the ancestry, seem to 
" exert a marked influence on the stature." 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 shewn '' by the great difference between the statures of soldiers 
" and sailors at the ages of seventeen and eighteen years." Mr. B. 
A. Gould endeavoured to ascertain the nature of the influences 
which thus act on stature ; but he arrived only at negative results, 
namely, that they did not relate to climate, the elevation of the 
land, soil, nor even " in any controlling degree " to the abundance 
or the need of the comforts of life. This latter conclusion is 
directly opposed to that arrived at by Villerme, from the statistics 
of the height of the conscripts in different parts of France. When 
we compare the differences in stature between the Polynesian 
chiefs and the lower orders within the same islands, or between 
the inhabitants of the fertile volcanic and 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 subsis- 
tence are very different, it is scarcely possible to avoid the con- 
clusion that better food and greater comfort do influence stature. 
But the preceding statements shew how difficult it is to arrive 
at any precise result. Dr. Beddoe has lately proved that, with 
the inhabitants of Britain, residence in towns and certain occupa- 
tions have a deteriorating influence on height ; and he infers that 
the result is to a certain extent inherited, as is likewise the case 
in the United States. Dr. Beddoe further believes that wherever 
a " race attains its maximum of physical development, it rises 
" highest in energy and moral vigour." ^^ 

Whether external conditions produce any other direct effect 
on man is not known. It might have been expected that dif-^ 
ferences of climate would have had a marked influence, in as much 
as the lungs and kidneys are brought into activity under a low 

" 'Investigations in Military and 289. There is also a remarkable 

Anthrop. Statistics,' &c. 1869, by ditlerence in appearance between 

B. A. Gould, p. 93, 107, 126, 131, the closely-allied Hindoos inhabiting 

134. the Upper Ganges and Bengal ; see 

'* For the Polynesians, see Prich- Elphinstone's ' History of India,' vol. 

ard's ' Physical Hist, of Mankind,' i. p. 324. 

vol. v. 1847, p. 145, 283. Also '^ ' Memoirs, Anthropolog. Soc. 

Godron, ' De I'Espfece,' torn. ii. p. vol. iii. 1867-69, pp. 561, 565, 567. 

32 The DesceJtt of Man. Part I. 

temperature, and the liver and skin under a high one.^ It was 
formerly thought that the colour of the skin and the character 
of the hair were determined by light or heat ; and although it 
can hardly be denied that some effect is thus produced, almost 
all observers now agree that the effect has been very small, even 
after exposure during many ages. But this subject will be more 
properly discussed when we treat of the different races of man- 
kind. With our domestic animals there are grounds for 
believing that cold and damp directly affect the growth of the 
hair ; but I have not met with any evidence on this head in the 
case of man. 

Effects of the iucnased Use and Disuse of Paris. — It is well 
known that use strengthens the muscles in the individual, and 
complete disuse, or the destruction of the proper nerve, weakens 
them. When the eye is destroyed, the optic nerve often becomes 
atrophied. When an artery is tied, the lateral channels increase 
not only in diameter, but in the thickness and strength of their 
coats. When one kidney ceases to act from disease, the other 
increases in size, and does double work. Bones increase not 
only in thickness, but in length, from carrying a greater weight.^^ 
Different occupations, habitually followed, lead to changed 
proportions in various parts of the body. Thus it was ascertained 
by the United States Commission ^^ that the legs of the sailors 
employed in the late war were longer by 0'217 of an inch than 
those of the soldiers, though the sailors were on an average 
shorter men ; whilst their arms were shorter by I 09 of an inch, 
and therefore, out of proportion, shorter in relation to their 
lesser height. This shortness of the arms is apparently due to 
their greater use, and is an unexi^ected result : but sailors 
chiefly use their arms in pulling, and not in supporting weights. 
With sailors, the girth of the neck and the depth of the instep 
are greater, whilst the circumference of the chest, waist, and 
hips is less, than in soldiers. 

Whether the several foregoing modifications would become 
hereditary, if the same habits of life were followed during many 
generations, is not known, but it is probable. Eengger^^ attri- 
butes the thin legs and thick arms of the Payaguas Indians to 

20 Dr. Brakenridge, ' Theory of Dr. Jaeger, " Ueber das Langen- 

Diathesis,' ' Medical Times,' June 19 wachsthum der Knochen," ' Jena- 

and July 17, 1869. ischen Zeitschrift,' B. v. Heft i. 

2* I have given authorities f(ir " ' Investigations,' &c. By B. A. 

these several statements in my Gould, 1869, p. 288. 

* Variation of Animals under Do- ^3 t Saugethiere von Paraguay, 

mestication,' vol. ii. pp. 297-300. 1830, s. 4. 

Chap. II. Manner of Development. 33 

successive generations liaring passed nearly their whole lives in 
canoes, with their lower extremities motionless. Other writers 
have come to a similar conclusion in analogous cases. According 
to Cranz/-^ who lived for a long time with the Esquimaux, " the 
" natives believe that ingenuity and dexterity in seal-catching 
" (their highest art and virtue) is hereditary ; there is really 
" somethiag in it, for the son of a celebrated seal-catcher will 
" distinguish himself, though he lost his father in childhood." 
But in this case it is mental aptitude, quite as much as bodily 
structure, which appears to be inherited. It is asserted that 
the hands of English labourers are at birth larger than those ot 
the gentry.-^ From the correlation which exists, at least in 
some cases,-^ between the development of the extremities and of 
the jaws, it is possible that in those classes which do not labour 
much with their hands and feet, the jaws would be reduced in 
size from this cause. That they are generally smaller in refined 
and civilised men than in hard-working men or savages, is certain. 
But with savages, as Mr. Herbert Spencer '""^ has remarked, the 
greater use of the jaws in chewing coarse, uncooked food, would 
act in a direct manner on the masticatory muscles, and on the 
bones to which they are attached. In infants, long before birth, 
the skin on the soles of the feet is thicker than on any other part 
of the body;-^ and it can hardly be doubted that this is due 
to the inherited effects of pressure during a long series of 

It is familiar to every one that watchmakers and engravei-s 
are liable to be short-sighted, whilst 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 w^ith savages, in eye- 
sight and in the other senses, is no doubt the accumulated and 
transmitted effect of lessened use during many generations ; for 
Eengger^^ states that he has repeatedly observed Europeans, 

^* 'History of Greenland,' Eng. ('Sanitary Memoirs of the War of 

translat. 17G7, vol. i. p. 230. the Rebellion,' 1869, p. 530), has 

2^ ' Intermarriage.' By Alex, proved this to be the case ; and h«' 

Walker, 1838, p. 377. accounts for it by the ordinal v 

^° 'The Variation of Animals range of vision in sailors being " n-- 

under Domestication,' vol. i, p. 173. " stricted to the length of the vcsm;! 

27 I. Principles of Biology,' vol. i. " and the height of tlie masts." 

p. 455. ^° 'The Variation of Animals 

28 Paget, ' Lectures on Surgical under Domestication,' vol. i. p. 8. 
Pathology,' vol. ii. 1853, p. 209. ^' ' Siingethiere von Paraguay,' 

2^ It is a singular and unex- s. 8, 10. I have had good opportuui- 

pected fact that sailors are interior ties for observing the extraordinarv 

to landsmen in their mean distance power of eyesight in the Fuegians. 

of distinct vision. Dr. B. A. Gould See also Lawrence (' lectures on 

34 T^he Descent of Alan. Part I, 

who had been brought up and spent their whole lives with the 
wild Indians, who nevertheless did not equal them in the sharp- 
ness of their senses. The same naturahst observes that the 
cavities in the skull for the reception of the several sense-organs 
are larger in the American aborigines than in Europeans ; and 
this probably indicates a corresponding difference in the dimen- 
sions of the organs themselves. Blumenbach has also remarked 
on the large size of the nasal cavities in the skulls of the 
American aborigines, and connects this fact with their remarkably 
acute power of smell. The Mongolians of the plains of Northern 
Asia, according to Pallas, have wonderfully perfect senses ; and 
Prichard believes that the great breadth of their skulls across 
the zygomas follows from their high]y-develox)ed sense-organs.^^ 
The Quechua Indians inhabit the lofty plateaux of Peru ; and 
Alcide d'Orbigny states ^^ that, from continually breathing a 
highly rarefied atmosphere, they have acquired chests and lungs 
of extraordinary dimensions. The cells, also, of the lungs are 
larger and more numerous than in Europeans. These observa- 
tions have been doubted ; but Mr. D. Forbes carefully measured 
many Aymaras, an allied race, living at the height of between 
10,000 and 15,000 feet; and he informs me 2* that they 
differ conspicuously from the men of all other races seen by him 
in the circumference and length of their bodies. In his table of 
measurements, the stature of each man is taken at 1000, and the 
other measurements are reduced to this standard. It is here 
seen that the extended arms of the Aymaras are shorter than 
those of Europeans, and much shorter than those of Negroes. 
The legs are likewise shorter ; and they present this remarkable 
peculiarity, that in every Aymara measured, the femur is actually 
shorter than the tibia. On an average, the length of the femur 
to that of the tibia is as 211 to 252 ; whilst in two Europeans, 
measured at the same time, the femora to the tibiae were as 2'44 
to 230; and in three Negroes as 258 to 211. The humerus is 
likewise shorter relatively to the forearm. This shortening of 
that part of the limb which is nearest to the body, appears to be, 
as suggested to me by Mr. Forbes, a case of compensation in 

Physiology,' &c., 1822, p. 404) on bach, vol. i. 1851, p. 311; for the 

this same subject. M. Giraud-Teulon statement by PaHas, a-o1. iv. 1844, 

has recently collected (' Revue des p. 407. 

Cours Scieutifiques,' 1870, p. 625) ^^ Quoted by Prichard, ' Re- 
a large and valuable body of evidence searches into the Phys. Hist, of Man- 
proving that the cause of short- kind,' vol. v. p. 463. 
sight, " Cest le travail assidu, de 34 ]\jj._ Forbes' valuable paper is 
pres." now published in the ' Journal of 
'2 Prichard, ' Phys. Hist, of Man- the Ethnological Sec. of London,* 
kind,' on the authoritv of F>lumen- new series, vnl. ii. 1870, p. 193. 

Chap. II. Manner of Devdopnient. 35 

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 acclimatised to their cold and 
lofty abode, that when formerly carried down by the Spaniards 
to the low eastern plains, and when now tempted down by high 
wages to the gold-washings, they suifer a frightful rate of mor- 
tality. Nevertheless Mr. Forbes found a few pure families 
which had survived during two generations : and he observed that 
they still inherited their characteristic peculiarities. But it was 
manifest, even without measurement, that these pecaharities 
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 ; wliilst their femora had become somewhat lengthened, 
as had their tibite, although in a less degree. The actual 
measurements may be seen by consulting Mr. Forbes's memoir. 
From these observations, there can, I think, be no doubt that 
residence during many generations at a great elevation tends, 
both directly and indirectly, to induce inherited modifications 
in the proportions of the body.^^ 

Although man may not have been much moiified during 
the latter- stages of his existence through the increased or de- 
creased use of parts, the facts now given shew that his liability in* 
this respect has not been lost ; and we positively know that the 
same law holds good with the lower animals. Consequently we 
may infer that when at a remote epoch the progenitors of man 
were in a transitional state, and were changing from quadrupeds 
into bipeds, natural selection would probably have been greatly 
aided by the inherited effects of the increased or diminished use 
of the different parts of the body. 

A rrests of Developmen f. — There is a difference between arrested 
development and arrested growth, for parts in the former state 
continue to grow whilst still retaining their early condition. 
Various riionstrosities come under this head ; and some, as a 
cleft-palate, are known to be occasionally inherited. It will 
suffice for our purpose to refer to the arrested brain-development 
of microcephalous idiots, as described in Yogt's memoir.''^ 
Their skulls are smaller, and the convolutions of the brain 
are less complex than in normal men. The frontal sinus, or the 

'^ Dr. Wilckens (' Landwirth- regions, have their frames modified, 
schaft. Wochenblatt,' No. 10, 1869) ^<* ' Me'moire sur les Microc6- 

has lately published an interesting phales,' 1867, jip. 50, 125, 169, 171, 

Essav shewing how domestic ani- 18-1-198. 
mals, which live in mountainous 

36 The Descent of Man. Part I. 

projection over the eye-brows, is largely developed, and the jaws 
are prognathous to an " effrayant'^ degree ; so that these idiots 
somewhat resemble the lower types of mankind. Their in- 
telligence, and most of their mental faculties, are extremely 
feeble. They cannot acquire the power of speech, and are 
wholly incapable of prolonged attention, but are much given to 
imitation. They are strong and remarkably active, continually 
gambohng 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 shewn by almost all boys in climbing trees; and this 
again reminds us how lambs and kids, originally alpine animals, 
delight to frisk on any hillock, however small. Idiots also 
resemble the lower animals in some other respects ; thus several 
cases are recorded of their carefully smelling every mouthful of 
food before eating it. One idiot is described as often using his 
mouth in aid of his hands, whilst hunting for lice. They are 
often filthy in their habits, and have no sense of decency ; and 
several cases have been published of their bodies being re- 
markably hairy ."'^ 

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 progenitor was 
probably constructed ; and it is hardly credible that a complex 
part, arrested at an early phase of embryonic development, should 
go on growing so as ultimately to perform its proper function, 
unless it had acquired such power during some earher 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 

3^ Prof. Laycock sums up the pp. 46-51. Pinel has also given a 

character of brute-like idiots by striking case of hairiness in an 

calling them theroid ; 'Journal of idiot. 

Mental Science,' July 1 863. Dr. ^* In my ' Variation of Animals 

Scott ('The Deaf and Dumb,' 2nd under Domestication ' (vol. ii. p. 57), 

edit., 1870, p. 10) has often ob- I attributed the not very rare cases 

served the imbecile smelling their of supernumerary mammae in women 

food. See, on this same subject, to reversion. I was led to this as a 

and on the hairmess of idiots, Dr. probable conclusion, by the additional 

Maudsley, ' Body and Mind,' 1870, mammae being generally placed 

Chap. II. 

Manner of Development, 


more strictly under oiir jiresent head of reversion. Certain 
structures, regularly occurring in the lower members of the group 

symmetrical!}' on the breast ; and 
more especially from one case, in 
whicii a single elHcient mamma 
occurred in the inguinal region of 
a woman, the daughter of another 
woman with supernumerary mam- 
mas. But I now find (see, for in- 
stance, Prof. Preyer, ' Der Kampf 
um das Dasein,' 1869, s. 45) that 
mamma: crraticcc occur in other 
situations, as on the back, in the 
armpit, and on the thigh ; the 
mammaj in this latter instance 
having given so much milk that the 
child was thus nourished. The pro- 
bability that the additional mammaj 
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 
mammje on the breast. Five cases 
have been recorded of the presence 
of more than a pair of mammte (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 Pieichert's and du 
Bois Reymond's Archiv., 1872, p. 
304. In one of the cases alluded to 
by Dr. Bartels, a man bore five 
mammas, one being medial and 
placed above the navel ; Meckel 
von Hemsbach thinks that this 
latter case is illustrated by a 
medial mamma occurring in certain 
Cheiroptera. On the whole, we may 
well doubt if additional mamma) 
would ever have been developed in 
both sexes of mankind, had not his 
early progenitors been provided with 
more than a single pair. 

In the above work (vol. ii. p, 12), 
I also attributed, though with much 
hesitation, the frequent cases of 

polydactylism in men to reversion. 
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 Zeitschrift,' B. v. Heft 
o, s. 341), disputes Owen's conclu- 
sion. On the other hand, according 
to the opinion lately advanced by 
Dx'. Gunther on the paddle of Ceia- 
todus, which is provided with ar- 
ticulated bony rays on both sides of 
a central chain of bones, there 
seems no great difficulty in admit- 
ting that six or more digits on one 
side, or double the number on both 
sides, might reappear through re- 
version. 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 is due to reversion from the 
fact that such digits not only are 
strongly inherited, but have the 
power of regrowth after amputa- 
tion, like the normal digits of the 
lower vertebrata. This fact of their 
regrowth remains inexplicable, if 
the belief in reversion to some ex- 
tremely remote progenitor is re- 
jected. Arrested development and 
reversion are intimately connected, 
and thus the belief in reversion in 
the present case is to a certain ex- 
tent supported by the frequent, or 
almost constant, coincidence insisted 
on by Meckel and I. Geotfroy St.- 
Hilaire, between various arrests of 
development, such as cleft-palate, 
bifid uterus, cyclopean state of the 
eyes, &c., and the presence of ad- 
ditional digits (see, on this head, 
M. A. Pionjou, 'Types Primitifs des 
Mammiferes,' p. Gl ; and M. Ber- 
tillon, ' Valeur Phil. Hyp. du Trans- 
formisme '). It is, on the other hand, 
no real objection to the view here 

2,S The Descent of Man. Pakt 1. 

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 normal in the lower 
members of the group. These remarks will be rendered clearer 
by the following illustrations. 

In yarious mammals the uterus graduates from a double 
organ, with two distinct orifices and two passages, as in the 
marsupials, into a single organ, which is in no way double, 
except from having a slight internal fold, as in the higher apes 
and man. The rodents exhibit a perfect series of gradations 
between these two extreme states. In all mammals the uterus 
is developed from two simple primitive tubes, the inferior 
portions of wliich form the cornua ; and it is, in the words of 
I)r. 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 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 so high up in the scale as the lower 
apes, and lemurs. 

Now in women, anomalous cases are not very infrequent, in 
which the mature uterus is furnished with cornua, or is partially 
divided into two organs; and such cases, according to Owen, 
repeat "the grade of concentrative development," attained by 
certain rodents. Here perhaps we have an instance of a simple 
arrest of embryonic development, with subsequent growth and 
perfect functional development ; for either side of the partially 
double uterus is capable of performing the proper office of 
gestation. In other and rarer cases, two distinct uterine cavities 
are formed, each having its proper orifice and passage.^^ No 
such stage is passed through during the ordinary development 
of the embryo, and it is difficult to beheve, 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 

maintained that supernumerary di- ultimately prevail, 

gits are often present without any ^^ See Dr. A. Farre's well-known 

other structure being affected ; for article in the ' Cyclop, of Anat. and 

numerous cases could be given Phys.' vol. v. 1859, p. 642. Owen 

of single characters reappearing ' Anatomy of Vertebrates,' vol. iii. 

through reversion. On the whole, 1868, p. 687. Prof. Turner in 

I cannot but think that the view ' Edinburgh Medical Journal,' Feb. 

originally propounded by me %vill 1805. 

Chap. II. Manner of Development. 39 

distinct uteri, each with a well-constructed orifice and passage, 
and each furnished with numerous muscles, nerves, glands and 
vessels, if they had not formerly passed through a similar course 
of development, as in the case of existing marsupials. No 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 develop- 
ment, even after the lapse of an enormous interval of time. 

Professor Canestrini, after discussing the foregoing and various 
analogous cases, arrives at the same conclusion as that just 
given. He adduces another instance, in the case of the malar 
bone,*" which, in some of the Quadrumana and other mammals, 
normally consists of two portions. This is its condition in the 
human foetus when two months old ; and through arrested develop- 
ment, it sometimes remains thus in man when adult, more 
especially in the lower prognathous races. Hence Canestrini 
concludes that some ancient progenitor of man must have had 
this bone normally divided into tvro portions, wiiich afterwards 
became fused together. In man the frontal bone consists of a 
single jDiece, but in the embryo, and in children, and in almost 
all the lower mammals, it consists of two pieces separated by a 
distinct suture. This suture occasionally persists more or less 
distinctly in man after maturity ; and more frequently in ancient 
than in recent crania, especially, as Canestrini has observed, in 
those exhumed from the Drift, and belonging to the brachyce- 
phalic 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 

*° ' Annuario della Soc. dei Xatu- tected in about two per cent, of 

ralisti in Modena,' 1867, p. 83. adult skulls; he also remarks that 

Prof. Canestrini gives extracts on it more frequently occurs in pro- 

this subject from various authorities. gnathous skulls, not of the Aryan 

Laurillard remarks, that as he has race, than in others. See also G. 

found a complete similarity in the Delorenzi on the same subject ; ' Tre 

form, proportions, and connection of nuovi cast d' auomalia dell'osso, 

the two malar bones in several malare,' Torino, 1872. . Also, E. 

human subjects and in certain apes, Morselli, ' Sopra una rara anomalia 

he cannot consider this disposition dell' osso malare,' Modena, 1872. 

of the parts as simply accidental. Still more recently Gruber has 

Another paper on this same anomaly written a pamjjlilet on the division 

has been published by Dr. Saviotti ofthisboue. 1 give these references 

in the ' Gazzetta delle Cliniche,' because a reviewer, without any 

Turin, 1871, where he says that grounds or scruples, has thrown 

traces of the divij,ion mav be de- doubts on mv statements. 

40 The Descent of Man. Part I. 

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.*^ 

In man, the canine teeth are perfectly efficient instruments for 
mastication. But their true canine character, as Owen*^ re- 
marks, " is indicated by the conical form of the crown, which 
** terminates in an obtuse point, is convex outward and flat or 
" sub-concave within, at the base of which surface there is a 
" feeble prominence. The conical form is best expressed in the 
" Blelanian races, especially the Australian. The canine is more 
" deeply implanted, and by a stronger fang than the incisors." 
Nevertheless, this tooth no longer serves man as a special weapon 
for tearing his enemies or prey ; it may, therefore, as far as its 
proper function is concerned, be considered as rudimentary. In 
every large collection of human skulls some may be found, as 
Hackel^^ observes, with the canine teeth projecting considerably 
beyond the others in the same manner as in the anthropomorphous 
apes, but in a less degree. In these cases, open spaces between 
the teeth in the one jaw are left for the reception of the canines 
of the opposite jaw. An interspace of this kind in a Kaffir 
skull, figured by Wagner, is surprisingly wide.^* 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.*^ 

*' A whole series of cases is given if in any way serviceable, for in- 

by Isid. GeofFroy St.-Hilaire, ' Hist, stance, in shortening and simplifying 

des Anomalies,' torn. iii. p. 437. the course of development ? And 

A reviewer (' Journal of Anat. and again, why should not injurious ab- 

Physiology,' 1871, p. 366) blames normalities, such as atrophied or hj-- 

me much for not having discussed pertrophied parfs, which have no 

the numerous cases, which have relation to a former state of exist- 

been recorded, of various parts ar- ence, occur at an early period, as 

rested in their development. He well as during maturity ? 

says that, according to my theory, 4- ' Anatomy of Vertebrates,' vol. 

" every transient condition of an iii. 1868, p. 323. 

" organ, during its development, is *^ ' Generelle Morphologie,' 1866, 

" not only a means to an end, but B. ii. s. civ. 

" once was an end in itself." This *^ Carl Vogt's 'Lectures on Man,' 

does not seem to me necessarily to Eng. translat. 1864, p. 151. 

hold good. Why should not varia- ^^ C. Carter Blake, on a jaw 

tions occur during an early period from La Naulette, ' Anthropolog. 

of development, having no relation Keview,' 1867, p. 295. Schaaff- 

to -"pvprsion ; yet such variations hausen, iliid. 1868, p. 426. 
might be preserved and accumul.ite'l. 

Chap. II. Manner of Development. 41 

Of the anthropomorphous apes the males alone have their 
canines fully developed ; but in the female gorilla, and in a less 
degree in the female orang, these teeth project considerably 
beyond the others; therefore the fact, of which I have been 
assured, that women sometimes have considerably projecting 
canines, is no serious objection to the belief that their occasional 
great development in man is a case of reversion to an ape-hke 
progenitor. He who rejects with scorn the belief that the shape 
of his own canines, and their occasional great development in 
other men, are due to our early forefathers having been pro- 
vided with these formidable weapons, will probably reveal, by 
sneering, the line of his descent. For though he no longer 
intends, nor has the power, to use these teeth as weapons, he will 
unconsciously retract his " snarling muscles" (thus named by 
Sir C. Bell),""' so as to expose them ready for action, like a dog 
prepared to fight. 

Many muscles are occasionally developed in man, which are 
proper to the Quadrumana or other mammals. Professor 
Ylacovich*' examined forty male subjects, and found a muscle, 
called by him the iscliio-pubic, in nineteen of them ; in three 
others there was a ligament which represented this muscle ; and 
in the remaining eighteen no trace of it. In only two out of 
thirty female subjects was this muscle developed on both sides, 
but in three others the rudimentary ligament was present. This 
muscle, therefore, appears to be much more common in the 
male than in the female sex ; and on the belief in the descent 
of man from some lower form, the fact is intelligible ; for it 
has been detected in several of the lower animals, and in all 
of these it serves exclusively to aid the male in the act of 

Mr. J. Wood, in his valuable series of papers,"*^ has minutely 
described a vast number of muscular variations in man, which 
resemble normal striPctures in the lower animals. The muscles 

<« 'The Anatomy of Expression,' pp. 241, 24-2; vol. xv. 1867, p. 544; 

1844, pp. 110, 131. vol. xvi. 1868, p. 524. I may here 

*' Quoted by Prof. Canestrini in add that Dr. Murie and Mr. St. 

the 'Annuario,' &c., 1867, p. 90. George Mivart have shewn in their 

^^ These papers deserve careful Memoir on the Lemuroidea (• Tran- 

study by any one who desires to sact. Zoolog. Soc' vol. vii. 1869, 

learn how frequently our muscles p. '^%\ how extraordinarily variable 

vary, and in varying come to re- some of the muscles are in these 

semble those of the Quadrumana. animals, the lowest members of the 

The following references relate to Primates. Gi-adations, also, in the 

the few points touched on in my muscles leading to structures found 

text: ' Proc. Royal Soc. vol. xiv. in animals still lower in the scale, 

1865, pp. 379-384; vol. xv. 186G, are numerous in tin? Lemuroidea. 

42 The Descent of Man. Part I. 

■which closely resemble those regularly present in our nearest 
allies, the Quadrumana, are too numerous to be here, even 
specified. In a single male subject, having a strong bodily 
frame, and well-formed skull, no less than seven muscular varia- 
tions were observed, all of which plainly represented muscles 
proper to various kinds of apes. This man, for instance, had on 
both sides of his neck a true and powerful " levator claviculce,'' 
such as is found in all kinds of apes, and which is said to occur 
in about one out of sixty human subjects."^ Again, this man 
had " a special abductor of the metatarsal bone of the fifth 
" digit, such as Professor Huxley and Mr. Flower have shewn 
" to exist uniformly in the higher and lower apes." I will give 
only two additional cases; the acromio-basilar muscle is found 
in all mammals below man, and seems to be correlated with a 
quadrupedal gait,^° and it occurs in about one out 0/ sixty 
human subjects. In the lower extremities Mr. Bradley ^^ 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 resem- 
blances are either perfect or imperfect; yet in the latter case 
they are manifestly of a transitional nature. Certain variations 
are more common in man, and others in woman, without our 
being able to assign any reason. Mr. Wood, after describing 
numerous variations, makes the following pregnant remark: 
" Notable departures from the ordinary type of the muscular 
" structures run in grooves or directions, which must be taken 
" to indicate some unknown factor, of much importance to a 
" comprehensive knowledge of general and scientific anatomy."*^ 

*^ See also Prof. Macalister in able case of variation in the human 

' Proc. R. Irish Academ}-,' vol. x. flexor poUicis longus, adds, " This 

1868, p. 124. " remarkable example shews that 

^" Mr. Champneys in ' Journal of " man may sometimes possess the 

Anat. and Phys.' Nov., 1871, p. 178. " arrangement of tendons of thumb 

51 'Journal of Anat. and Phys.' "and fingers characteristic of the 

May, 1872, p. 421. "macaque; but whether such a 

*2 Prof, Macalister (ibid. p. 121) " case should be regarded as a 
has tabulated his observations, and " macaque passing upwards into a 
finds that muscular abnormalities " man, or a man passing downwards 
are most frequent in the fore-arms, " into a macaque, or as a congenital 
secondly, in the face, thirdly, in the " freak of nature, I cannot under- 
foot &c. " take to say." It is satisfactory 

*^ The Rev. Dr. Haughton, after to hear so capable an anatomist, 

giving (' Proc. R. Irish Academy,' and so embittered an opponent of 

June°27, 1864, p. 71o) a remark- evolutionism, admitting even the 

Chap. II. Manner of Development. 43 

That this unknown factor is reTcrsion to a former state of 
existence may be admitted as in the highest degree probable.'^* 
It is quite incredible that a man should through mere accident 
abnormally resemble certain apes in no less than seven of his 
muscles, if there had been no genetic connection between them. 
On the other hand, if man is descended from some ape-like 
creature, no valid reason can be assigned why certain muscles 
should not suddenly reappear after an interval of many thou- 
sand generations, in the same manner as with horses, asses, and 
mules, dark-coloured stripes suddenly reappear on the legs, 
and shoulders, after an interval of hundreds, or more probably 
of thousands of generations. 

These various cases of reversion are so closely related to those 
of rudmientary organs given in the first chapter, that many of 
them might have been indifferently introduced either there or 
here. Thus a human uterus furnished with cornua may be said 
to represent, in a rudimentary condition, the same organ in its 
normal state in certain mammals. Some parts which are rudi- 
mentary in man, as the os coccyx in both sexes, and the mammee 
in the male sex, are always present ; whilst others, such as the 
supracondyloid foramen, only occasionally appear, and therefore 
might have been introduced under the head of reversion. These 
several reversionary structures, as well as the strictly rudi- 
mentary ones, reveal the descent of man from some lower form 
in an unmistakable manner. 

Correlated Variation. — 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 i^art governs the 
other, or whether both are governed by some earlier developed 

possiibility of either of his first pro- closely the variations resemble the 

positions. Prof. Macalister has also normal muscles of the lower ani- 

describeJ (' Proc. R. Irish Acad.' mals. He sums up by remarking, 

vol. X. 1864, p. 138) variations in " It will be enough for my purpose 

the/ej:or/)oWiciS /on^M5, remarkable "if I have succeeded in shewing 

from their relations to the same " the more important forms whicli, 

muscle in the Quadrumann. " when occurring as varieties in the 

^■* Since the first edition of this *' human subject, tend to exhibit in 

book appeared, Mr. Wood has pub- " a sufficiently marked manner what 

lished another memoir in the ' Phil. " may be considered as proofs and 

Transactions,' 1870, p. 83, on the " examples of the Darwinian prin- 

varieties of the muscles of the human " ciple of reversion, or law of in- 

neck, shoulder, and chest. He here " heritance, in this department ot 

shews how extremely variable these " anatomical science." 
muscles are, and how often and how 

44 The Descent of Man. Part I. 

part. Various monstrosities, as I. Geoffroy repeatedly insists, are 
thus intimately connected. Homologous structures are par- 
ticularly liable to change together, as we see on the opposite 
sides of the body, and in the upper and lower extremities. 
Meckel long ago remarked, that when the muscles of the arm 
depart from their proper type, they almost always imitate those 
of the leg ; and so, conversely, with the muscles of the legs. The 
organs of sight and hearing, the teeth and hair, the colour of the 
skin and of the hair, colour and constitution, are more or less cor- 
related.^^ Professor Schaaffhausen first drew attention to the 
relation apparently existing between a muscular frame and 
the strongly-pronounced supra-orbital ridges, which are so 
characteristic of the lower races of man. 

Besides the variations which can be grouped with more or 
less probability under the foregoing heads, there is a large class 
of variations which may be provisionally called spontaneous, for 
to our ignorance they appear to arise without any exciting 
cause. It can, however, be shewn that such variations, whether 
consisting of slight individual differences, or of strongly-marked 
and abrupt deviations of structure, depend much more on the 
constitution of the organism than on the nature of the condi- 
tions to which it has been subjected.^^ 

Bate of Increase. — Civilised populations have been known 
under favourable conditions, as in the United States, to double 
their numbers in twenty-five years ; and, according to a calcula- 
tion by Euler, this might occur in a little over twelve years.^'^ At 
the former rate, the present population of the United States 
(thirty millions), would in 657 years cover the whole terraqueous 
globe so thickly, that four men would have to stand on each 
square yard of surface. The primary or fundamental check to 
the continued increase of man is the difficulty of gaining 
subsistence, and of living in comfort. We may infer that this is 
the case from what we see, for instance, in the United States, 
where subsistence is easy, and there is plenty of room. If such 
means were suddenly doubled in Great Britain, our number would 
be quickly doubled. With civilised nations this primary check 
acts chiefly by restraining marriages. The greater death-rate of 
infants in the poorest classes is also very important; as well as 

'* The authorities for these seve- my ' Variation of Animals and Plants 

ral statements are given in my under Domestication.' 
'Variation of Animals under Do- *^ See the ever memorable 'Essay 

mestication,' vol. ii. pp. 320-335, on the Principle of Population,' by 

^^ This whole subject has been the Rev. T. Malthus, vol. i. 1826, p, 

discussed in chap, xxiii. vol. ii. of 6, 517. 

Chap. U. jMajiucr of Dcvelopnieiit. 45 

the gi-eatcr mortality, from various diseases, of the inhabitants of 
crowded and miserable houses, at all ages. The effects of severe 
epidemics and wars are soon counterbalanced, and more than 
counterbalanced, in nations placed under favourable conditions. 
Emigration also comes in aid as a temporary check, but, with 
the extremely poor classes, not to any great extent. 

There is reason to suspect, as Malthus has remarked, that the 
reproductive power is actually less in barbarous, than in civilised 
races. We know nothing positively on this head, for with 
savages no census has been taken; but from the concurrent 
testimony of missionaries, and of others who have long resided 
with such people, it appears that their families are usually small, 
and large ones rare. This may be partly accounted for, as it is 
believed, by the women suckling their infants during a long 
time ; but it is highly probable that savages, who often suffer 
much hardship, and who do not obtain so much nutritious food 
as civilised men, would be actually less prolific. I have shewn 
in a former work,^^ that all our domesticated quadrupeds and 
birds, and all our cultivated plants, are more fertile than the 
corresponding species in a state of nature. It is no valid 
objection to this conclusion that animals suddenly supplied with 
an excess of food, or when grown very fat ; and that most plants 
on sudden removal from very poor to very rich soil, are 
rendered more or less sterile. We might, therefore, expect that 
civilised men, who in one sense are highly domesticated, would 
be more prolific than wild men. It is also probable that the 
increased fertility of civilised nations would become, as with our 
domestic animals, an inherited character : it is at least known 
that with mankind a tendency to produce twins runs in 

Notwithstanding that savages appear to be less prolific than 
civilised people, they would no doubt rapidly increase if their 
numbers were not by some means rigidly kept down. The San- 
tali, or hill-tril)es of India, have recently afforded a good illustra- 
tion of this fact ; for, as shewn by Mr. Hunter,*^ they have 
increased at an extraordinary rate since vaccination has been 
introduced, other pestilences mitigated, and war sternly repressed. 
This increase, however, would not have been possible had not 
these rude people spread into the adjoining districts, and worked 
for hire. Savages almost always marry ; yet there is some 
prudential restraint, for they do not commonly marry at the 

** 'Variation of Animals, and Foreign Medico-Chirurg. Pieview,' 

Plants under Domestication,' vol. ii. July, 1863, p. 170. 
pp. 111-113, 163. «« ' The Annals of Rural Bengal,' 

" Mr. Sedgwick, 'British and bv \V. W. Hunter, 1868, p. 259. 

46 The Descent of Man. Part I. 

earliest possible age. The young men are often required to shew 
that they can support a wife ; and they generally have first to 
earn the price with which to purchase her from her parents. 
With savages the difficulty of obtaining subsistence occasionally 
limits their number in a much more direct manner than with 
civilised people, for all tribes periodically suffer from severe 
famines. At such times savages are forced to devour much bad 
food, and their health can hardly fail to be injured. Many 
accounts have been published of their protruding stomachs and 
emaciated limbs after and during famines. They are then, also, 
compelled to wander much, and, as I was assured in Australia, 
their infants perish in large numbers. As famines are period- 
ical, depending chiefly on extreme seasons, all tribes must 
fluctuate in number. They cannot steadily and regularly 
increase, as there is no artificial increase in the supply of .food. 
Savages, when hard pressed, encroach on each other's territories, 
and war is the result ; but they are indeed almost always at war 
with their neighbours. They are liable to many accidents on 
land and water in their search for food ; and in some countries 
they sufi"er much from the larger beasts of prey. Even in 
India, districts have been depopulated by the ravages of 

Malthus has discussed these several checks, but he does not 
lay stress enough on what is probably the most important of all, 
namely infanticide, especially of female infants, and the habit of 
procuring abortion. These practices now prevail in many 
quarters of the world ; and infanticide seems formerly to have 
prevailed, as Mr. ]\['Lennan'^^ has shewn, on a still more extensive 
scale. These practices appear to have originated in savages re- 
cognising the difficulty, or rather the impossibility of supporting 
all the infants that are born. Licentiousness may also be added 
to the foregoing checks; but this does not follow from failing 
means of subsistence ; though there is reason to believe that in 
some cases (as in Japan) it has been intentionally encouraged 
as a means of keeping down the population. 

If we look back to an extremely remote epoch, before man had 
arrived at the dignity of manhood, he would have been guided 
more by instinct and less by reason than are the lowest savages 
at the present time. Our early semi-human progenitors would 
not have practised infanticide or polyandry ; for the instincts of 
the lower animals are never so perverted ^- as to lead them re- 

** ' Primitive Marriage,' 1865. ments as follows on this passage : — 

^^ A writer in the 'Spectator' " Mr. Darwin finds himself compelled 

(March 12th, 1871, p. 320) com- " to reintroduce a new doctrine of the 

Chap. II. Manner of Devclopuient. 47 

gularly to destroy their own offspring, or to be quite devoid of 
jealousy. There would have been no prudential restraint from 
marriage, and the sexes would have freely united at an early age. 
Hence the progenitors of man would have tended to increase 
rapidly; but checks of some kind, either periodical or constant, 
must have kept down their numbers, even more severely than 
with existing savages. What the precise nature of these checks 
were, we cannot say, any more than with most other animals. 
We know that horses and cattle, which are not extremely prolific 
animals, when first turned loose in South America, increased at 
an enormous rate. The elephant, the slowest breeder of all 
known animals, would in a few thousand years stock the whole 
world. The increase of every species of monkey must be 
checked by some means; but not, as Brehm remarks, by the 
attacks of beasts of prey. No one w^ill 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 in this case, and in all others, many checks concur, 
and different checks under different circumstances ; periodical 
dearths, depending on unfavourable seasons, being probably the 
most important of all. So it will have been with the early pro- 
genitors of man. 

Natural Selection. — We have now seen that man is variable in 
body and mind; and that the variations are induced, either 
directly or indirectly, by the same general causes, and obey the 
same general laws, as with the low^er animals. Man has spread 
widely over the face of the earth, and must have been exposed, 
during his incessant migrations,^^ to the most diversified con- 
ditions. The inhabitants of Tierra del Fuego, the Cape of Good 
Hope, and Tasmania in the one hemisphere, and of the Arctic 
regions in the other, must have passed through many climates, 

" fiill of man. He shews that the *' by the many foul customs, es- 

" instincts of the higher animals " pecially as to marriage, of savage 

" are far nobler than the habits of " tribes. What does the Jewish 

" savage races of men, and he finds " tradition of the moral degonera- 

" himself, therefore, compelled to " tion of man through his snatching 

" re-introduce, — in a form of the " at a knowledge forbidden him 

" substantial orthodoxy of which he " by his highest instinct a'^sert 

" appears to be quite unconscious, — " beyond this?" 

" and to introduce as a scientific ®^ See some good remarks to this 

" hypothesis the doctrine that man's effect by W. Stanley Jevons, " A 

" gain of knoicledje was the cause of " Deduction from Darwin's Theory," 

"a temporary but long-enduriug ' Nature,' 1869, p. 231. 
" moral deterioration, as indicated 

48 TJie Descent of Man. Part I. 

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 individual differences. We know, for instance, 
that the muscles of our hands and feet, which determine our 
powers of movement, are liable, hke those of the lower animals,^^ 
to incessant variability. If then the progenitors of man inhabit- 
ing any district, especially one undergoing some change in its 
conditions, were divided into two equal bodies, the one half 
which included all the individuals best adapted by their powers 
of movement for gaining subsistence, or for defending themselves, 
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 that any other highly organised form : and 
all others have yielded before him. He manifestly owes this 
immense superiority to his intellectual faculties, to his social 
habits, wliich 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 :®s " a psychological 
" analysis of the faculty of language shews, that even the smallest 
" proficiency in it might require more brain power than the 
" greatest proficiency in any other direction.'' He has invented 
and is able to use various weapons, tools, traps, &c., with which 
he defends himself, kills or catches prey, and otherwise obtains 
food. He has made rafts or canoes for fishing or crossing over 
to neighbouring fertile islands. He has discovered the art of 

^* Latham, ' Man and his Migra- " classed in any of the above 

tions,' 1851, p. 135. " groups." These muscles differ 

•^^ Messrs. Murie and Mivart in even on the opposite sides of the 

their 'Anatomy of the Lemuroidea' same individual. 

(' Transact. Zoolog. Soc' vol. vii. ^^ Limits of Natural Selection, 

1869, pp. 96-98) say, "some- muscles 'North American Review,' Oct. 

" are so irregular in their distribu- 1870, p. 295. 
" tion that" they cannot be well 

Chap. II. Manner of Develcpmeiit. 49 

making fire, by wliicli hard and stringy roots can be rendered 
digestible, and poisonous roots or herbs innocuous. This dis- 
covery of fire, probably the greatest ever made by man, excepting 
language, dates from before the dawn of history. These several 
inventions, by wliich 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" main- 
tains, that ** natural selection could only have endowpd 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 remain- 
der of this chapter will be devoted ; the development of the in- 
tellectual and social or moral faculties being discussed in a later 

Even to hammer with precision is no easy matter, as every 
one who has tried to learn carpentry will admit. To throw^ a 
stone with as true an aim as a Fuegian in defending himself, or 
in killing birds, requires the most consummate perfection in the 
correlated action of the muscles of the hand, arm, and shoulder, 
and, further, a fine sense of touch. In throwing a stone or spear, 
and in many other actions, a man 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,^^ remarks, 
the shaping fragments of stone into knives, lances, or arrows-heads, 

°^ ' Quarterly Review,' April hoi-e resist quoting a most just 

1869, p. 392. 'This subject is more remark by Sir J. Lubbock (' Pre- 
fuUy discussed in Mr. Wallace's historic Times,' 1865, p. 479) in 
' Contributions to the Theory of reference to this paper, namely, that 
Natural Selection,' 1870, in which Mr. Wallace, "with characteristic 
all the essays referred lo in this " unselfishness, ascribes it (i. e. the 
work are republished. The ' Essay " idea of natural selection) unre- 
on Man ' has been ably criticised by " servedly to Mr. Darwin, although, 
Prof. Claparede, one of the most " as is well known, he struck out 
distinguished zoologists in Europe, " the idea independently, and pub- 
in an article published iu the " lished it, though not with the 
' Bibliotheque Universelle,' June " same elaboration, at the same 

1870. The remark quoted in my " time." 

text will surprise every one who ®* Quoted by Mr. Lawson Tait in 
has read Mr. Wallace's celebrated his ' Law of Natural Selection,' — 
paper on 'The Origin of Human ' Dublin Quarterly Journal of Modi- 
Races deduced from the Theory of cal Science,' Feb. 1869. Dr. Keller 
Natural Selection,' originally pub- is likewise quoted to the same 
lished in the ' Anthropological Re- effect, 
view,' !^L^y 1864, p. chili. I cannot 

50 The Descent of Man. Part I. 

shews " extraordinary ability and long practice." This is to a 
great extent proved by the fact that primeyal men practised a 
division of labour; each man did not manufacture his own flint 
tools or rude pottery, but certain individuals appear to have 
devoted themselves to such work, no doubt receiving in exchange 
the produce of the chase. Archaeologists are convinced that an 
enormous interval of time elapsed before our ancestors thought 
of grinding chipped flints into smooth tools. One can hardly 
doubt, that a man-like animal who possessed a hand and arm 
sufficiently perfect to throw a stone with precision, or to form a 
flint into a rude tool, could, with sufficient joractice, as far as 
mechanical skill alone is concerned, make almost anything 
which a civilised man can make. The structure of the hand in 
this respect may be compared with that of the vocal organs, 
which in the apes are used for uttering various signal-cries, or, 
as in one genus, musical cadences; but in man the closely 
similar vocal organs have become adapted through the inherited 
eifects of use for the utterance of articulate language. 

Turning now to the nearest aUies 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 diver- 
sified uses. Their hands do not serve for locomotion so well 
as the feet of a dog ; as may be seen in such monkeys as the 
chimpanzee and orang, which walk on the outer margins of 
the palms, or on the knuckles. ^^ Their hands, however, are 
acbnirably adapted for climbing trees. Monkeys seize thin 
branches or ropes, with the thumb on one side and the fingers 
and jDalm on the other, in the same manner as we do. They can 
thus also lift rather large objects, such as the neck of a bottle, to 
their mouths. Baboons turn over stones, and scratch up roots 
with their hands. They seize nuts, insects, or other small 
objects with the thumb in opposition to the fingers, and no 
doubt they thus extract eggs and the young from the nests of 
bii'ds. American monkeys beat the wild oranges on the branches 
until the rind is ci-acked, and then tear it off with the fingers of 
the two hands. In a wild state they break open hard fruits 
with stones. Other monkeys open mussel-shells with the two 
thumbs- With their fingers they pull out thorns and burs, and 
hunt for each other's parasites. They roll down stones, or throw 
them at their enemies : nevertheless, they are clumsy in these 
various actions, and, as I have myself seen, are quite unable to 
tlirow a stone with precision, 

*^ Owen, Anatomy of Vertebrattis/ vol. iii. p. 71. 

CiiAi II. Manner of Development. 51 

It seems to me far from true that because " objects are grasped 
" clumsily " by monkeys, " a much less specialised organ of 
" prehension " would have served them ''" 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. iii 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 oncient 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 attitude, which forms one of his most 
conspicuous characters. Man could not have attained his present 
dominant posijtion in the world without the use of his hands, 
which are so admirably adapted to act in obedience to his will. 
Sir C. Bell "^ insists that " the hand supplies all instruments, 
" and by its correspondence with the intellect gives him univer- 
" sal dominion." But the hands and arms could hardly have 
become perfect enough to have manufactured weapons, or to 
have hurled stones and sj)ears 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 

^0 ' Quarterly Review,' April but whether a better climber than 

1869, p. 392. the species of the allied genera, 1 do 

'1 In IrLjlohntcs siindactylus, as not know. It deserves notice that 

the name expresses, two of the toes the feet of the sloths, the most 

regularly cohere ; and this, as Mr. arboreal animals in the world, are 

Blyth informs me, is occasionally wonderfully hook-like, 

the case with the toes of H. a(]ilis, " Brehm, ' Thierlobon,' B. i. s, 

/a;-, and /eucj'scMS. Colobus is strictly 80. 

arboreal and extraordinarily active "' ''The Hand," <&:c. * Bridge- 

(Brehm, ' Thierleben,' B. i. s. 50), water Treatise,' 1833, p. 38. 

52 The Descent of Man. Part I. 

many actions it is indispensable that the arms and whole upper 
part of the body should be free ; and he must for this end stand 
firmly on his feet. To gain this great advantage, the feet have 
been rendered flat ; and the great toe has been peculiarly modi- 
fied, though this has entailed the almost complete loss of its 
power of prehension. It accords with the principle of the 
division of physiological labour, prevailing throughout the 
animal kingdom, that as the hands became perfected for i^re- 
hension, the feet should have become perfected for support and ■ 
locomotion. "With some savages, however, the foot has not 
altogether lost its prehensile power, as shewn by their manner 
of climbing trees, and of using them in other ways.'^* 

If it be an advantage to man to stand firmly on his feet and to 
have his hands and arms free, of which, from his pre-eminent 
success in the battle of life, there can be no doubt, then I can see 
no reason why it should not have been advantageous to the 
progenitors of man to have become more and more erect or 
bipedal. They would thus have been better able to defend 
themselves with stones or clubs, to attack their prey, or other- 
wise to obtain food. The best built individuals would in the 
long run have succeeded best, and have survived in larger 
numbers. If the gorilla and a few allied forms had becomn. 
extinct, it might have been argued, with great force and apparent 
truth, that an animal could not have been gradually converted 
from a quadruped into a biped, as all the individuals in an 
intermediate condition would have been miserably ill-fitted 
for progression. But we know (and this is well worthy of 
reflection) that the anthropomorphous apes are now actually in 
an intermediate condition ; and no one doubts that they are 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 existing monkeys a manner of 
progression intermediate between that of a quadruped and a 

^* Hackel has an excellent dis- foot as a prehensile organ by man ; 

cussion on the steps by which man and has also written on the manner 

became a biped: ' Natiirliche Schop- of progression of the higher apes, to 

fungsgeschichte,' 1868, s. 507. Dr. Avhich I allude in the following 

Biichner (' Conferences sur la Theorie paragraph : see also Owen (' Anatomy 

Darwinienne,' 1869, p. 135) has of Vertebrates,' vol, iii. p. 71) on 

given good cases of the use of the this latter subject. 

C: H A p. I r . Manner of Developnien t. 53 

biped ; but, as an unprejudiced judge '^ insists, the anthropomor- 
phous apes approach in structure more nearly to the bipedal 
than to the quadrupedal type. 

As the progenitors of man became more and more erect, with 
their hands and arms more and more modified for prehension 
and other purposes, with their feet and legs at the same time 
transformed for firm support and progression, endless other 
changes of structure would have become necessary. The pelvis 
•would have to be broadened, the spine peculiarly curved, and the 
head fixed in an altered position, all which changes have been 
attained by man. Prof. Schaaflihausen " maintains that "the 
" powerful mastoid processes of the human skull are the result of 
" his erect position ;" and these processes are absent in the orang, 
chimpanzee, &c., and are smaller in the gorilla than in man. 
Various other structures, which appear connected with man's 
erect position, might here have been added. It is very difficult 
to decide how far these correlated modifications are the result of 
natural selection, and how far of the inherited effects of the 
increased use of certain parts, or of the action of one part on 
another. No doubt these means of change often co-operate : thus 
when certain muscles, and the crests of bone to which they are 
attached, become enlarged by habitual use, this shews that 
certain actions are habitually performed and must be serviceable. 
Hence the individuals which performed them best, would tend 
to survive in greater numbers. 

The free use of the arms and hands, partly the cause and 
partly the result of man's erect position, appears to have led in an 
indirect manner to other modifications of structure. The early 
male forefathers of man were, as previously stated, jDrobably 
furnished with great canine teeth; but as they gradually 
acquired the habit of using stones, clubs, or other weaj^ons, 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, w^ould become reduced in size, as we may feel almost sure 
from innumerable analogous cases. In a future chapter we 
shall meet with a closely parallel case, in the reduction or com- 
plete disappearance of the canine teeth in male ruminants, 
apparently in relation with the development of their horns ; and 
in horses, in relation to tlieii' habit of fighting with their incisor 
teeth and hoofs. 

" Prof. Broca, La Constitution the Skull,' translated iu ' Authro- 

des Vertfebres ciiudales; 'La Revue pological Review,' Oct. 18*38, p. 

d'Anthropologie,' 1872, p. iG, 428. Owen (' Anatomy of Verte- 

(separate copy) brates,' vol. ii. 1866, p. 551) on the 

'•^ 'On the rrimitive Form of mastoid processes in the higher apes. 

54 The Descent of Man. Tart I. 

In the adult male anthropomorphous apes, as Eutimeyer/''" 
and others, have insisted, it is the effect on the skull of the great 
development of the jaw-muscles that causes it to differ so greatly 
in many respects from that of man, and has given to these 
animals " a truly frightful physiognomy." Therefore, as the jaws 
and teeth in man's progenitors gradually became reduced in size, 
the adult skull would have come to resemble more and more 
that of existing man. As we shall hereafter see, a great reduction 
of the canine teeth in the males would almost certainly affect the 
teeth of the females through inheritance. 

As the various mental faculties gradually developed themselves 
the brain would almost certainly become larger. No one, I 
presume, doubts that the large proportion which the size of 
man's brain bears to his body, compared to the same proportion 
in the gorilla or orang, is closely connected vfith his higher 
mental powers. We meet with closely analogous facts with 
insects, for in ants the cerebral ganglia are of extraordinary 
dimensions, and in all the Hymenoptera these ganglia are many 
times larger than in the less intelligent orders, such as beetles. '^^ 
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, a-nd affections of ants are notorious, 
yet their cerebral ganglia are not so large as the quarter of a 
small pin's head. Under this point of view, the brain of an ant is 
one of the most marvellous atoms of matter in the world, perhaps 
more so than the brain of a man. 

The belief that there exists in man some close relation between 
the size of the brain and the development of the intellectual 
faculties is supported by the comparison of the skulls of savage 
and civilised races, of ancient and modern people, and by the 
analogy of the whole vertebrate series. Dr. J. Barnard Davis has 
proved,'^^ by many careful measurements, that the mean internal 
capacity of the skull in Europeans is 92-3 cubic inches; in 
Americans 87-5; in Asiatics 871 ; and in Australians only 81-9 - 
cubic inches. Professor Broca ^^ found that the nineteenth century 

^^ 'Die Grenzen der Thierwelt, vomitoria* 1870, p. 14. Mv son, 

oine Betrachtung zu Darwin's Lehre,' Mr. F. Darwin, dissected for ine the 

1868, s. 51. cerebral ganglia of the Formica 

^^ Dujardin, ' Annales des Sc. rttfa. 

Nat,' 3rd series Zoolog. torn, xiv. ''^ < Philosophical Transactions, 

1850, p. 203. See also Mr. Lowne, 1869, p. 513. 

'Anatomy and Phys. of the 3Imca 8<> ' Les Selections,' M. P. Broca, 

Cji A P. I [ . Manner of Development, 5 5 

skulls from graves in Paris were larger than those from -vaults 
of the twelfth century, in the proportion of 1-184 to 1426 ; and 
that the increased size, as ascertained by measurements, was 
exclusively in the frontal part of the skull — the seat of the 
intellectual faculties. Prichard is persuaded that the present 
inhabitants of Britain have " much more capacious brain-cases " 
than the ancient inhabitants. Nevertheless, it must be admitted 
that some skulls of very high antiquity, such as the famous one 
of Neanderthal, are well developed and capacious.^^ 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 convolutions are more complex in the 
more recent forms. On the other hand, I have shewn^^ that the 
brains of domestic rabbits are considerably reduced in bulk, in 
comparison with those of the wild rabbit or hare ; and this may be 
attributed to their having been closely confined during many 
generations, so that they have exerted their intellect, instincts, 
senses and voluntary movements but little. 

The gi'adually increasing weight of the brain and skull in 
man must have influenced the development of the supporting 
spinal column, more especially whilst he was becoming erect. 
As this change of iDOsition was being brought about, the internal 
pressure of the brain will also have influenced the form of the 
skull ; for many facts show how easily the skull is thus affected. 
Ethnologists believe that it is modified by the kind of cradle in 
which infants sleep. Habitual spasms of the muscles, and a 
cicatrix from a severe burn, have permanently modified the facial 
bones. In young persons whose heads have become fixed either 
sideways or backwards, o\ving to disease, one of the two eyes has 
changed its position, and the shape of the skull has been altered 

' Revue d'Anthropologies,' 1873 ; the other hand, with savages, the ave- 

see also, as quoted in C. Vogt's rage includes only the more capable 

' Lectures on Man,' Eng. translat. individuals, who have been able to 

1864, pp. 88, 90. Prichard, ' Phys. survive under extremely hard con- 

Hist. of Mankind,' vol. i. 1838, p. ditions of lite. Broca thus explains 

305, the otherwise inexplicable fact, that 

*' In the interecting article just the mean capacity of the skull of 

referred to. Prof. Broca has well the ancient Troglodytes of Lozere is 

remarked, that in civilised nations, greater than that ot modern French- 

the average capacity of the skull men. 

must be lowered by the preserva- "- ' Comptes-rendus des Sciences,' 

tion of a considerable number of (Sec. June 1, 18G8. 

individuals, weak in mind aud body, ^^ 'The Variation of Animals and 

who would have been promptly Plants under Domestication,' vol. i. 

eliminated in the savage state. On pp. 124-129. 

56 The Descent of Man. Part I. 

apparently by the pressure of the brain in a new direction.^* 
I have shewn 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, whilst others have retained nearly the same size, 
but in both cases the brain has been much reduced relatively to 
the size of the body. Now I was at first much sui'prised on 
finding that in all these rabbits the skull had become elongated 
or dolichocephalic; for instance, of two skulls of nearly equal 
breadth, the one from a wild rabbit and the other from a large 
domestic kind, the former was 3-15 and the latter 4-3 inches in 
length.^5 One of the most marked distinctions in difierent 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 dolicho- 

From these several facts we can understand, to a certain 
extent, the means by which the great size and more or less 
rounded form of the skull have been acquired by man ; and these 
are characters eminently distinctive of him in comparison with 
the lower animals. 

Another most conspicuous difference between man and the 
lower animals is the nakedness of his skin. Whales and 
porpoises (Cetacea), dugongs (Sirenia) and the hippopotamus are 
naked; and this may be advantageous to them for gliding 

** SchaafFhausen gives fi-om Blu- maker, where the head is habitually 

menbach and Busch, the cases of the held forward, the forehead becomes 

spasms and cicatrix, in 'Anthro- more rounded and })rominent. 

polog. Review,' Oct. 1868, p. 420. ^^ 'Variation of Animals,' &c., 

Dr. Jarrold (' Anthropologia,' 1808, vol. i. p. 117, on the elongation of 

pp. 115, 116) adduces from Camper the skull; p. 119, on the efi'ect of 

and from his own observations, cases the lopping of one ear. 

of the modification of the skull from ^"^ Quoted by Schaaffhausen, in 

the head being fixed in an unnatural ' Anthropolog. Review,' Oct. 18G8, 

position. He believes that in cer- p. 419. 
t.iin trades, such as that of a shoe- 

Chap. II. Maimer of Development. 57 

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 rhino- 
ceroses are almost hairless ; and as certain extinct species, 
which formerly lived under an Arctic climate, were covered with 
long wool or hair, it would almost appear as if the existing 
species of both genera had lost their hairy covering from exposure 
to heat. This appears the more probable, as the elephants in 
India which live "on elevated and cool districts are more hairy ^^ 
than those on the lowlands. May we then infer that man 
became divested of hair from having aboriginally inhabited some 
tropical land ? That the hair is chiefly retained in the male sex on 
the chest and face, and in both sexes at the junction of all four 
limbs with the trunk, favours this inference — on the assumption 
that the hair was lost before man became erect ; for the parts 
which now retain most hair would then have been most protected 
from the heat of the sun. The crown of the head, however, 
offers a curious exception, for at all times it must have been one 
of the most exposed parts, yet it is thickly clothed with hair. 
The fact, however, that the other members of the order of 
Primates, to which man belongs, although inhabiting various hot 
regions, are well clothed with hair, generally thickest on the upper 
surface,*^ is o^Dposed 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 jDarasites, 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 have, as far as I know, 
acquired any specialised means of relief. The view which seems 
to me the most probable is that man, or rather primarily woman, 

*^ Osven, 'Anatomy of Yerte- ever, states that in the Gorilla the 

brates,' vol. iii. p. 619. hair is thinner on the back, where 

** Isidore Geotfroy St.-Hilaire re- it is partly rubbed oil", than on the 

marks (' Hist. Nat. Generale,' torn, lower surface. 

ii. 1859, pp. 215-217) on the head of ^^ The ' Naturalist in Nicaragua,' 

man being covered with long hair; 1874, p. 209. As some confirma- 

also on the upper surfaces of mon- tion of Mr. Belt's view, I may quote 

keys and of other mammals being the following passage from Sir VV. 

more thickly clothed than the lower Denison (' Varieties of Vice-Kegal 

surfaces. This has likewise been Life,' vol. i. 1870, p. 440): " It is said 

observed by various authors. Prof. " to be a })ractice with the Aus- 

P. Gervais (' Hist. Nat. des Mam- " tralians, when the vermin get 

mifbres,' torn. i. 1854, p. 28), how- " troublesome, to twinge themselves." 

58 The Descent of Man. Part I. 

became divested of hair for omamenial purposes, as we sliall see 
under Sexual Selection ; and, according to this belief, it is not 
surprising that man should diifer so greatly in hairiness from all 
other Primates, for characters, gained through sexual selection, 
often differ to an extraordinary degree in closely-related forms. 

According to a popular impression, the absence of a tail is 
eminently distinctive of man ; but as those apes which come 
nearest to him are destitute of this organ, its disapi^earance 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 
vertebrre; in others it consists of a scarcely visible stumj^, 
containing only three or four vertebi-se. In some kinds of 
baboons there are twenty-five, whilst in the mandrill there are 
ten very small stunted caudal vertebrae, or, according to Cuvier,®° 
sometimes only five. The tail, whether it be long or short, almost 
always tapers towards the end ; and this, I presume, results from 
the atrophy of the terminal muscles, together with their arteries 
and nerves, through disuse, leading to the atrophy of the terminal 
bones. But no explanation can at present be given of the great 
diversity which often occurs in its length. Here, however, we 
are more specially concerned with the complete external dis- 
appearance of the tail. Professor Broca has recently shewn ^^ 
that the tail in all quadrupeds consists of two portions, generally 
separated abruptly from each other ; the basal portion consists 
of vertebras, more or less perfectly channelled and furnished with 
apophyses like ordinary vertebrae ; whereas those of the terminal 
portion are not channelled, are almost smooth, and scarcely 
resemble true vertebrae, A tail, though not externally visible, is 
really present in man and the anthropomorphous apes, and is 
constructed on exactly the same pattern in both. In the terminal 
l^ortion the vertebrae, constituting the os coccyx, are quite 
rudimentary, being much reduced in size and nimiber. In the 
basal portion, the vertebrae are likewise few, are united firmly 
together, and are arrested in development; but they have been 
rendered much broader and flatter than the corresponding 
vertebrae in the tails of other animals : they constitute what 
Broca calls the accessory sacral vertebrte. These are of functional 
importance by supporting certain internal parts and in other 
ways ; and theii' modification is directly connected with the erect 

^^ Ml , St. George Mivart, ' Proc. Geoffroy, ' Hist. Xat. Gen.' torn. ii. 

Zoolog. Soc' 1865, pp. 562, 583. p. 244. 

Dr. J.E. Gray, 'Cat. Brit. Mus.: ^^ 'Revue d'Anthropologie,' 1872 ; 

Skeletons.' Owen, ' Anatomy of ' La Constitution des Yertebres cau- 

Vertebrates,' vol. ii. p. 517. Isidore dales.' 

Chap. II. Manner of Development. 59 

or semi-erect attitude of man and the anthropomorphous apes. 
This conclusion is the more trustworthy, as Broca formerly held 
a different view, which he has now abandoned. The modifica- 
tion, therefore, of the basal caudal vertebrae in man and the 
higher apes may have been effected, directly or indirectly, 
through natural selection. 

But what arc we to say about the rudimentary and variable 
vertebrae of the terminal portion of the tail, forming the os coccyx ? 
A notion which has often been, and will no doubt again be 
ridiculed, namely, that friction has had something to do with 
the disappearance of the external portion of the tail, is not 
so ridiculous as it at first appears. Dr. Anderson '-"^ states 
that the extremely short tail of Macacus hrnnneus is formed of 
eleven vertebrae, including the imbedded basal ones. The 
extremity is tendinous and contains no vertebrae ; this is suc- 
ceeded by five rudimentary ones, so minute that together they 
are only one line and a half in length, and these are permanently 
bent to one side in the shape of a hook. The free part of the 
tail, only a little above an inch in length, includes only four more 
small vertebrae. This short tail is carried erect; but about a 
quarter of its total length is doubled on to itself to the left ; and 
tliis terminal part, which includes the hook-like portion, serves 
" to fill up the interspace between the upper divergent portion 
" of the callosities ;" so that the animal sits on it, and thus renders 
it rough and callous. Dr. Anderson thus sums up his observa- 
tions : " These facts seem to me to have only one explanation ; 
" this tail, from its short size, is in the monkey's way when it 
" sits down, and frequently becomes placed under the animal 
*' while it is in this attitude ; and from the circumstance that it 
" does not extend beyond the extremity of the ischial tuberosities 
" it seems as if the tail originally had been bent round, by the 
" will of the animal, into the interspace between the callosities, to 
" escape being pressed between them and the ground, and that 
" in time the curvature became permanent, fitting in of itself 
" when the organ happens to be sat upon." Under these circum- 
stances it is not surprising that the surface of the tail should 
liave 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 " is necessarily thrust 
" to one side of the buttocks ; and whether long or short its root 
" is consequently liable to be rubbed or chafed." As we now 

»2 'Proc. Zoolog. Soc.,' 1872, p. " * Proc. Zoolog. Sue. 1872, p. 

210. 786. 

6o The Descent of Man. Part I 

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, should after 
many generations have become rudimentary and distorted, from 
being continually rubbed and chafed. We see the projecting part in 
this condition in the Macacushruimeus, and. absolutely aborted in 
the if. ecaudatus and in several of the higher apes. Finally, then, 
as far as we can judge, the tail has disappeared in man and the 
anthropomorphous apes, owing to the terminal portion having 
been injured by friction during a long lapse of time ; the basal 
and embedded portion having been reduced and modified, so as 
to become suitable to the erect or semi-erect position. 

I have now endeavoured to shew that some of the most 
distinctive characters of man have in all probabiHty been 
acquii-ed, either directly, or more commonly indirectly, through 
natural selection. We should bear in mind that modifications 
in structure or constitution, which do not serve to adapt an 
organism to its habits of life, to the food which it consumes, or 
passively to the surrounding conditions, cannot have been thus 
acquired. We must not, however, be too confident in decidnig 
what modifications are of service to each being: we should 
remember ho^^ 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 con-elation, by which, as Isidore Geoffroy 
has shewn in the case of man, many strange deviations of 
structure are tied together. Independently of correlation, a 
change in one part often leads, through the increased or decreased 
use of other parts, to other changes of a quite unexpected 
nature. It is also well to reflect on such facts, as the wonderful 
growth of galls on plants caused by the poison of an insect, and 
on the remarkable changes of colour in the plumage of parrots 
when fed on certain fishes, or inoculated with the poison of 
toads ;^^ 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 

5* I allude to Dr. Brown-Sequard's inherited effects of mot-mots biting 
observations on the transmitted off the barbs of their own tail- 
effect of an operation causing epi- feathers. See jlso on the general 
lepsy in guinea-pigs, and likewise subject ' Variation of Animals and 
more recently on the analogous Plants under Domestication,' vol. 
effects of cutting the sympathetic ii., pp. 22-24. 

nerve in the neck. I shall hereafter ^^ ' The Variation of Animals and 

have occasion to refer to Mr. Salvin's Plants under Domestication/ vol. ii. 

interesting case of the apparently pp. 280, 282. 

CiiAi'. II. Manner of Development. 61 

and continually used during past ages for some useful purpose, 
would probably become firmly fixed, and might be long inherited. 

Thus a large yet undefined extension may safely be given to 
the direct and indirect results of natural selection ; but I now 
admit, after reading the essay by NUgeli on plants, and the 
remarks by yarious authors with respect to animals, more 
especially those recently made by Professor Broca, that in the 
earlier editions of my * Origin of Species ' I perhaps attributed 
too much to the action of natural selection or the survival 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 structures which now appear to us useless, will 
hereafter be proved to be useful, and will therefore come within 
the range of natui'al selection. Nevertheless, I did not formerly 
consider sufficiently the existence of structures, which, as far as 
we can at present judge, are neither beneficial nor injurious ; 
and this I believe to be one of the greatest oversights as yet 
detected in my work. I may be permitted to say, as some 
excuse, that I had two distinct objects in view; firstly, to 
shew that species had not been separately created, and secondly, 
that natural selection had been the chief agent of change, 
though largely aided by the inherited effects of habit, and slightly 
by the dii-ect action of the surrounding conditions. I was 
not, however, able to annul the influence of my former belief, 
then almost universal, that each species had been purposely 
created ; and this led to my tacit assumption that every detail 
of structure, excepting rudiments, was of some special, though 
unrecognised, service. Any one with this assimiption in his 
mind would naturally extend too far the action of natural 
selection, either during past or present times. Some of those 
who admit the principle of evolution, but reject natural selec- 
tion, seem to forget, when criticising my book, that I had the 
above two objects in view ; hence if I have erred in giving to 
natural selection great power, which I am very far from 
admitting, or in having exaggerated its power, which is in itself 
probable, I have at least, as I hope, done good service in aiding 
to overthrow the dogma of separate creations. 

It is, as I can now see, probable that all organic beings, 
including man, possess peculiarities of structure, which neither 
are now, nor were formerly of any service to them, and which, 
therefore, are of no physiological importance. Wo know not 
what produces the numberless slight difierenccs between the 
individuals of each species, for reversion only carries the 
problem a few steps backwards; but each peculiarity must 

62 The Descent of Man. Taut I. 

have had its efficient cause. If these causes, whatever they 
may be, were to act more -uniformly and energetically during a 
lengthened period (and against this no reason can be assigned), 
the result w^ould probably be not a mere slight individual 
difference, but a well-marked and constant modification, though 
one of no physiological importance. Chauged structures, which 
are in no w^ay beneficial, cannot be kept uniform through natural 
selection, though the injurious will be thus eliminated. Uni- 
formity of character would, however, naturally follow from the 
assumed nniformity of the exciting causes, and likewise from 
the free intercrossing of many individuals. During successive 
periods, the same organism might in this manner acquire 
successive modifications, w^hich would be transmitted in a nearly 
uniform state as long as the exciting causes remained the same 
and there w^as free intercrossing. With respect to the exciting 
causes we can only say, as when speaking of so-called spon- 
taneous variations, that they relate much more closely to the 
constitution of the varying organism, than to the nature of the 
conditions to which it has been subjected. 

Conclusion.— In this chapter we have seen that as man at the 
present day is liable, like every other animal, to multiform 
individual differences or slight variations, so no doubt were the 
early progenitors of man ; the variations being formerly induced 
by the same general causes, and governed by the same general 
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 natural selection. The latter 
process would be greatly aided by the inherited effects of the 
increased use of parts, and these two processes would incessantly 
react on each other. It appears, also, as we shall hereafter see, 
that various unimportant characters have been acquired by man 
through sexual selection. An unexplained residuum of change 
must be left to the assumed uniform action of those unknown 
agencies, which occasionally induce strongly marked and abrupt 
deviations of structure in our domestic productions. 

Judging from the habits of savages and of the greater number 
of the Quadrumana, primeval men, and even their ape-hke 
progenitors, probably lived in society. With strictly social 
animals, natural selection sometimes acts on the individual, 
through the preservation of variations which are beneficial to 
the community. A community which includes a large number 
of well-endowed individuals increases in number, and is victo- 
rious over other less favoured ones ; even although each separate 

Cjiai'. II. Manner of Devdopmcjit. 6^ 

member gains no advantage over the others of the same com- 
munity. Associated insects have thus acquired many remark- 
able structures^ M'hich are of little or no service to the individual, 
such as the pollen-collecting apparatus, or tlie sting of the 
worker-bee, or the great jaws of soldier-ants. With the liigher 
social animals, I am not aware that any structure has been 
modified solely for the good of the community, though some are 
of secondary service to it. For instance, the horns of ruminants 
and the great canine teeth of baboons appear to liave been 
acquired by the males as weapons for sexual strife, but they are 
used in defence of the herd or troop. In regard to certain 
mental powers the case, as we shall see in the fifth chapter, is 
wholly dificrent ; for these faculties have been chiefly, or even 
exclusively, gained for the benefit of the community, and the 
individuals thereof, have at the same time gained an advantage 

It has often been objected to such views as the foregoing, that 
man is one of the most helpless and defenceless creatures in the 
uorld; 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 direction of 
" greater physical helplessness and weakness. That is to say, it 
" is a divergence which of all others it is most impossible to 
" ascribe to mere natural selection." He adduces the naked and 
unprotected state of the body, the absence of great teeth or 
claws for defence, the small strength and speed of man, and his 
shght power of discovering food or of avoiding danger by smell. 
To these deficiencies there might be added one still more 
serious, namely, that he cannot climb quickly, and so escape 
from enemies. The loss of hair would not have been a great 
injury to the inhabitants of a warm country. For we know that the 
unclothed Fuegians can exist under a wretched climate. When 
we compare the defenceless state of man with that of apes, we 
must remember that the great canine teeth with which the latter 
are provided, are possessed in their full development by the males 
alone, and are chiefly used by them for fighting with their rivals ; 
yet the females, which are not thus provided, manage to survive. 

In regard to bodily size or strength, we do not know whether 
man is descended from some small species, hke the chimpanzee, 
or from one as powerful as the gorilla; and, therefore, we cannot 
say whether man has become lai-ger and stronger, or smaller 

»« ' Primeval Man,' 1869, p. ^<o. 

64 The Descent of Man. Takt I. 

and weaker, than his ancestors. 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 perhajjs have become social; and this would most 
effectually 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 s^^rung 
from some comparatively weak creature. 

The small strength and speed of man, his want of natural 
weapons, &c., are more than counterbalanced, firstly, by his 
intellectual powers, through which he has formed for himself 
weapons, tools, &c., though still remaining in a barbarous state, 
and, secondly, by his social qualities which lead him to give and 
receive aid from his fellow-men. No country in the world abounds 
in a gi-eater degree with dangerous beasts than Southern Africa ; 
no country presents more fearful physical hardships than the 
Arctic regions; yet one of the puniest of races, that of the 
Bushmen, maintains itself in Southern Africa, as do the dwarfed 
Esquimaux in the Arctic regions. The ancestors of man were, no 
doubt, inferior in intellect, and probably in social disposition, to 
the lowest existing savages ; but it is quite conceivable that they 
might have existed, or even flourished, if they had advanced in 
intellect, whilst gradually losing their brute-like powers, such 
as that of climbing trees, &c. But these ancestors would not 
have been exposed to any special danger, even if far more 
helpless and defenceless than any existing savages, had they 
inhabited some warm continent or large island, such as 
Austraha, New Guinea, or Borneo, which is now the home of the 
orang. And natural selection arising from the competition of 
tribe with tribe, in some such large area as one of these, together 
with the inherited effects of habit, would, under favourable 
conditions, have sufficed to raise man to his present high position 
in the organic scale. 

Chap. III. Mental Poivers. 65 


Comparison of the Mental Powers of Man and the 
Lower Animals. 

The difference in mental power between the highest ape and the lowest 
savage, immense — Certain instincts in common — The emotions — 
Curiosity — Imitation — Attention — Memory — Imagination — Reason — 
Progressive improvement — Tools and weapons used by animals — 
Abstraction, self-consciousness — Language — Sense of beauty — Belief in 
God, spiritual agencies, superstitions. 

We have seen in the last two chapters that man bears in his 
bodily structure clear traces of his descent from some lower 
form ; but it may be urged that, as man differs so greatly in 
his mental power from all other animals, there must be some 
error in this conclusion. No doubt the difference in this 
respect is enormous, even if we compare the mind of one of the 
lowest savages, who has no words to express any number higher 
than four, and who uses hardly any abstract terms for common 
objects or for the affections,^ with that of the most highly 
organised ape. The difference would, no doubt, still remain 
immense, even if one of the higher apes had been improved or 
civilised as much as a dog has been in comparison with itt> 
parent-form, the wolf or jackal. The Fuegians rank amongst 
the lowest barbarians; but I was continually struck with 
surprise how closely the three natives on board H.M.S. '' Beagle," 
who had lived some years in England, and could talk a little 
English, resembled us in disposition and in most of our mental 
faculties. If no organic being excepting man had possessed any 
mental power, or if his powers had been of a wholly different 
nature from those of the lower animals, then we should never 
have been able to convince ourselves that our high faculties 
had been gradually developed. But it can be shewn that there 
is no fundamental difference of this kind. We must also admit 
that there is a much wider interval in mental power between 
one of the lowest fishes, as a lamprey or lancelet, and one of the 
higher apes, than between an ai)e 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 

* See the evidence on those points, as given by Lubboclc, ' Prehistoric 
Times,' p. 354, &c. 

66 TJie Descent of Man. Part I. 

Byron, -who dashed his child on the rocks for dropping a basket 
of sea-urchins, and a Howard or Clarkson; and in intellect, 
between a savage who uses hardly any abstract terms, and a 
Newton or Shakspeare. Differences of this kind between the 
highest men of the highest races and the lowest savages, are 
connected by the finest gradations. Therefore it is possible that 
they might pass and be developed into each other. 

My object in this chapter is to shew that there is no funda- 
mental difference between man and the higher mammals in their 
mental faculties. Each division of the subject might have been 
extended into a separate essay, but must here be treated briefly. 
As no classification of the mental i:>owers has been universally 
accepted, I shall arrange my remarks in the order most con- 
venient for my purpose ; and will select those facts which have 
struck me most, with the hope that they may produce some 
effect on the reader. 

With respect to animals very low in the scale, I shall give 
some additional facts under Sexual Selection, shewing that their 
mental powers are much higher than might have been expected. 
The variability of the faculties in the individuals of the same 
species is an important point for us, and some few illustrations 
will here be given. But it would be superfluous to enter into 
many details on this head, for I have found on frequent enquiry, 
that it is the unanimous opinion of all those who have long 
attended to animals of many kinds, including birds, that the 
individuals difibr greatly in every mental characteristic. In 
what manner the mental powers were first developed in the 
lowest organisms, is as hojoeless an enquiry as how life itself 
first originated. These are problems for the distant future, if 
they are ever to be solved by man. 

As man possesses the same senses as the lower animals, his 
fundamental intuitions must be the same. Man has also some 
few instincts in common, as that of self-preservation, sexual love, 
the love of the mother for her new-born offspring, the desire 
possessed by the latter to suck, and so forth. But man, perhaps, 
has somewhat fewer instincts than those possessed by the 
animals which come next to him in the series. The orang in 
the Eastern islands, and the chimpanzee in Africa, build plat- 
forms on which they sleep ; and, as both species follow the same 
habit, it might be argued that this was due to instinct, but we 
cannot feel 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 

Chap. II r. Mental Powers. 6y 

turned out in the spring, often eat poisonous lierbs, which they 
afterwards 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, certain, 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 instincts in 
the higher animals are remarkable in contrast with those of the 
lower animals. Cuvicr maintained that instinct and intelligence 
stand in an inverse ratio to each other ; and some have thought 
that the intellectual f\iculties of the higher animals have been 
gradually developed from their instincts. But Pouchet, in an 
interesting essay,- has shewn that no such inverse ratio really 
exists. Those insects which possess the most wonderful instincts 
are certainly the most intelligent. In the vertebrate series, the 
least intelligent members, namely fishes and amphibians, do not 
possess complex instincts; and amongst mammals the animal 
most remarkable for its instincts, namely the beaver, is highly 
intelligent, as will be admitted by every one who has read Mr. 
Morgan's excellent work.^ 

Although the first dawnings of intelligence, according to jMr. 
Herbert Spencer,* have been developed through the multiplica- 
tion and co-ordination of reflex actions, and although many of 
the simpler instincts graduate into reflex actions, and can hardly 
be distinguished from them, as in the cnse of young animals 
sucking, yet the more complex instincts seem to have originated 
independently of intelligence. I am, however, very far from 
wishing to deny that instinctive actions may lose their fixed and 
untaught character, and be replaced by others performed by the 
aid of the free will. On the other hand, some intelligent actions, 
after being performed during several generations, become con- 
verted into instincts and are inherited, as when birds on oceanic 
islands learn to avoid man. These actions may then be said 
to be degraded in character, for they are no longer performed 
through reason or from experience. 13ut the greater number of 
the more complex instincts appear to have been gained in a 
wholly different manner, through the natural selection of varia- 
tions of simjilcr instinctive actions. Such variations ai')pear to 
arise from the same unknown causes acting on the cerebral 
organisation, which induce slight variations or individual dif- 
ferences in other parts of the body ; and these variations, owing 

^ * L'Instinct chez les Inscctos.' ' ' The American Beaver and his 

' Revue des Deux Mondes,' Feb. 1870, Works,' 1868. 

p. G90. ■* ' The Principles of Psychology, 

2nd edit. 1870, pp. 418-443. 

68 The Descent of Man. Part I. 

to our ignorance, are often said to arise spontaneously. We can, 
I think, come to no other conclusion with respect to the origin of 
the more complex instincts, when we reflect on the marvellous 
instincts of sterile worker-ants and bees, which leave no off- 
spring to inherit the effects of experience and of modified habits. 

Although, as we learn from the above-mentioned insects and 
the beaver, a high degree of intelligence is certainly compatible 
with complex instincts, and although actions, at first learnt 
voluntarily can soon through habit be performed with the 
quickness and certainty of a reflex action, yet it is not improbable 
that there is a certain amount of interference between the 
development of free intelligence and of instinct, — which latter 
imphes some inherited modification of the brain. Little is 
known about the functions of the brain, but we can perceive 
that as the intellectual powers become highly developed, the 
various parts of the brain must be connected by very intricate 
channels of the freest intercommunication; and as a conse- 
quence, each separate part would perhaps tend to be less well fitted 
to answer to particular sensations or associations in a definite 
and inherited— that is instinctive— manner. There seems even 
to exist some relation between a low degTce of intelligence and a 
strong tendency to the formation of fixed, though not inherited 
habits ; for as a sagacious physician remarked to me, persons 
who are slightly imbecile tend to act in everything by routine 
or habit ; and they are rendered much happier if this is en- 

I have thought this digression worth giving, because we may 
easily underrate the mental powers of the higher animals, and 
especially of man, when we compare their actions founded on the 
memory of past events, on foresight, reason, and imagination, 
with exactly similar actions instinctively performed by the lower 
animals; in this latter case the capacity of performing such 
actions has been gained, step by step, through the variability of 
the mental organs and natural selection, without any conscious 
inteUigenCe on the part of the animal during each successive 
generation. No doubt, as Mr. Wallace has argued,^ much of the 
intelligent work done by man is due to imitation and not to 
reason; but there is this great difference between his actions 
and many of those performed by the lower animals, namely, that 
man cannot, on his first trial, make, for instance, a stone hatchet 
or a canoe, through his power of imitation. He has to learn his 
work by practice ; a beaver, on the other hand, can make its 
dam or canal, and a bird its nest, as well, or nearly as well, and 

' 'Contributions to the Theory of Natural Selection,' 1870, p. 212. 

Chap. III. Mental Powers. 69 

a spider its wonderful web, quite as well,'' the fii-st 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. 
Haj^piness is never better exhibited than by young animals, such 
as i^uiDpies, kittens, lambs, &c., when playing together, like our 
own childi'en. 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 muscles to 
tremble, the heart to palpitate, the sphincters to be relaxed, and 
the hair to stand on end. Suspicion, the offspring of fear, is 
eminently characteristic of most wild animals. It is, I think, 
impossible to read the account given by Sir E. Tennent, of the 
behaviour of the female elephants, used as decoys, without 
admitting that they intentionally practise deceit, and well know 
what they are about. Courage and timidity are extremely 
variable qualities in the individuals of the same species, as is 
plainly seen in our dogs. Some dogs and horses are ill-tempered, 
and easily turn sulky ; others are good-temi>ered ; and these 
qualities are certainly inherited. Every one knows how liable 
animals are to furious rage, and how plainly they show it. 
Many, and probably true, anecdotes have been published on the 
long-delayed and artful revenge of various animals. The 
accurate Eengger, and Brehm^ state that the American and 
African monkeys which they kept tame, certainly revenged 
themselves. Sir Andrew Smith, a zoologist whose scrupulous 
accuracy was known to many persons, told me the following 
story of which he was himself an eye-witness; at the Cape 
of Good Hope an officer had often i)lagned a certain baboon, 
and the animal, seeing him approaching one Sunday for 
parade, poured water into a hole and hastily made some thick 
mud, which he skilfully dashed over the officer as he passed 
by, to the amusement of many bystanders. For long after- 
wards the baboon rejoiced and triumi^hcd whenever he saw his 

6 For the evidence on this « All the following statements, 

heail, see Mr. J. Traherue Mog- given on the authority of these two 

gridge's most interesting work, naturalists, are taken from Rongger's 

'Harvesting Ants and Trap-door 'Naturgesch. der Siingethiere von 

Spiders,' 1873, p. 126, 128. Paraguay,' 1830, s. 41-57, and from 

^ ' Recherches sur les Mceurs dcs Brehm's 'Thierlehen,' B. i. s. 10-87. 
Fourmis,' 1810, p. 173. 

70 The Descent of Man. Tart I. 

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." 

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 oiDeration 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 WhewelP^ has well asked, " who that reads the touching 
" 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 mater- 
nal affection exliibited in the most trifling details ; thus Eengger 
observed an American monkey (a Cebus) carefully driving away 
the flies which plagued her infant; and Duvaucel saw a 
Hylobates washing the faces of her young ones in a stream. So 
intense is the grief of female monkeys for the loss of their 
young, that it invariably caused the death of certain kinds kept 
under confinement by Brehm in N. Africa. Orphan monkeys 
were always adopted and carefully guarded by the other monkeys, 
both males and females. One female baboon had so capacious 
a heart that she not only adopted young monkeys of other 
species, but stole young dogs and cats, which she continually 
carried about. Her kindness, however, did not go so far as to 
share her food with her adopted offspring, at which Brehm was 
surprised, as his monkeys always divided everythiDg quite 
fairly with their own young ones. An adopted kitten scratched 
this affectionate baboon, who certainly had a fine intellect, for 
she was much astonished at being scratched, and immediately 
examined the kitten's feet, and without more ado bit off the 
claws.^^ In the Zoological Gardens, I heard from the keeper 
that an old baboon (C, chacmci) had adopted a Ehesus monkey; 
but when a young drill and mandrill were placed in the cage, 
she seemed to perceive that these monkeys, though distinct 
species, were her nearer relatives, for she at once rejected the 
Ehesus and adopted both of them. The young Ehesus, 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 

3 Quoted by Dr. Lauder Lindsay, 72), disputes the possibility of this. 

u his ' Physiology of Mind in the act as described by Brehm, for the 

Lower Animals ;' ' Journal of Mental sake of discrediting my work. 

Science,' April 1871, p. 38. Therefore I tried, and found that I 

10 ' BridiT-ewater Treatise,' p. 263. could readily seize with my own 

^1 A critic, without any grounds teeth the sharp little claws of a 

('Quarterly Review,' July 1871, p. kitten nearly five weeks old. 

CuAP. III. Mental Powers, yi 

whenever it could do so with safety ; this conduct exciting great 
indignation in the old baboon. Monkeys will also, according to 
Brehm, defend their master when attacked by any one, as well as 
dogs to whom they are attached, from the attacks of other dogs. 
But we here trench on the subjects of sympathy and fidelity, to 
which I shall recur. Some of Brehm's monkeys took much 
delight in teasing a certain old dog whom they disliked, as 
well as other animals, in various ingenious ways. 

Most of ihe more complex emotions arc common to the 
higher animals and ourselves. Every one has seen how jealous 
a dog is of his master's affection, if lavished on any other 
creature ; and I have observed the same fact with monkeys. 
Tliis shews that animals not only love, but have desire to bo 
loved. Animals manifestly feel emulation. They love ajipro- 
bation or praise ; and a dog carrying a basket for his master 
exhibits in a high degree self-complacency or pride. There can, 
I think, be no doubt that a dog feels shame, as distinct from 
fear, and something very like modesty when begging too often 
for food. A great dog scorns the snarling of a httle dog, and 
this may be called magnanimity. Several observers have stated 
that monkeys certainly dislike being laughed at ; and they 
sometimes invent imaginary offences. In the Zoological Gardens 
I saw a baboon who always got into a furious rage v/hen his 
keeper took out a letter or book and read it aloud to him ; and 
his rage was so violent that, as I witnessed on one occasion, he 
bit his own leg till the blood flowed. Dogs show what may be 
fairly called a sense of humour, as distinct from mere jilay ; if 
a bit of stick or other such object be thrown to one, he will often 
carry it away for a short distance ; and then squatting down 
with it on the ground close before him, will wait until his 
master comes quite close to take it away. The dog will then 
seize it and rush away in triumph, repeating the same manoeuvre, 
and evidently enjoying the practical joke. 

Wo will now turn to the more intellectual emotions and 
faculties, which are very important, as forming the basis for the 
development of the higher mental powers. Animals manifestly 
enjoy excitement, and suffer from ennui, as may be seen with 
dogs, and, according to Eengger, with monkeys. All animals 
feel Wonder, and many exhibit Curiositij. They sometimes 
suffer from this latter quality, as when the hunter plays antics 
and thus attracts them ; I have witnessed this with doer, and so 
it is with the wary chamois, and with some kinds of wild-ducks. 
Brehm gives a curious account of the instinctive dread, which 
his monkeys exhibited, for snakes; but their curiosity was 
so great that they could not desist from occasionally satiating 

72 The Descent of Man. Part I. 

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 comx)artments. After a time all the monkeys 
collected round it in a large ch'cle, and staring intently, 
presented a most ludicrous appearance. They became extremely 
nervous ; so that when a wooden ball, with which they were 
familiar as a plaything, was accidentally moved in the straw, 
under which it was partly hidden, they all instantly started 
away. These monkeys behaved very differently when a dead 
fish, a mouse,^^ a living turtle, and other new objects were placed 
in their cages; for though at fkst frightened, they soon 
approached, handled and examined them. I then placed a live 
snake in a paper bag, with the mouth loosely closed, in one of 
the larger compartments. One of the monkeys immediately 
approached, cautiously opened the bag a little, peeped in, and 
instantly dashed away. Then I witnessed what Brehm has 
described, for monkey after monkey, with head raised high and 
turned on one side, could not resist taking a momentary peep 
into the upright bag, at the dreadful object lying quietly at the 
bottom. It would almost appear as if monkeys had some 
notion of zoological affinities, for those kept by Brehm exhibited 
a strange, though mistaken, instinctive di-ead of innocent lizards 
and frogs.. An orang, also, has been known to be much alarmed 
at the first sight of a turtle.^^ 

The principle of Imitation is strong in man, and especially, as 
I have myself observed, with savages. In certain morbid states 
of the brain this tendency is exaggerated to an extraordinary 
degree ; some hemiplegic patients and others, at the commence- 
ment of inflammatory softening of the brain, unconsciously 
imitate every word which is uttered, whether in their own or in 
a foreign language, and every gesture or action which is per- 
formed near them.-* Desor^^ has remarked that no animal 

^2 I have given a short account of Mammalia,' 1841, p. 405. 
of their behaviour on this occasion '* Dr. Bateman ' On Aphasia,' 

in my 'Expression of the Emotions,' 1870, p. 110. 
p. 43. *' Quoted by Vogt, 'Me'moire sur 

»3 \V. C. L. Martin, 'Nat. Hist, les Microcephales,' 1867, p. 168. 

CiL^.p. III. Mental Powers. 73 

volunt<arily 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, wliich had been 
reared by dogs, learned to bark, as docs sometimes the jackal,"^ 
but whether this can bo called voluntary imitation is another 
question. Birds imitate the songs of their parents, and some- 
times of other birds ; and parrots are notorious imitators of any 
sound which they often hear. Bureau de la Malic gives an 
account ^^ of a dog reared by a cat, who learnt to imitate the 
well-known action of a cat licking her paws, and thus washing 
her ears and face; this was also witnessed by the celebrated 
naturalist Audouin. I have received several confirmatory ac- 
counts ; in one of these, a dog had not been suckled by a cat, 
but had been brought up with one, together with kittens, and 
had thus acquired the above habit, which he ever afterwards 
practised during his life of thirteen years. Dureau de la Malle's 
dog likewise learnt from the kittens to play with a ball by roll- 
ing it about with his fore paws, and springing on it. A corre- 
spondent assures me that a cat in his house used to put her paws 
into jugs of milk having too narrow a mouth for her head. A 
kitten of tliis cat soon learned the same trick, and practised it 
ever afterwards, whenever there was an opportunity. 

The parents of many animals, trusting to the principle of 
imitation in their young, and more especially to their instinctive 
or inherited tendencies, may be said to educate them. "We see 
this when a cat brings a live mouse to her kittens ; and Dureau 
de la Malle has given a curious account (in the paper above 
quoted) of his observations on hawks which taught their young 
dexterity, as well as judgment of distances, by first chopping 
through the air dead mice and sparrows, which the young 
generally failed to catch, and then bringing them live birds 
and letting them loose. 

Hardly any faculty is more important for the intellectual 
progress of man than Attention. Animals clearly manifest this 
power, as when a cat watches by a hole and prepares to spring 
on its prey. Wild animals sometimes become so absorbed when 
thus engaged, that they may be easily approached. Mr. Bartlett 
has given me a curious proof how variable this faculty is in 
monkeys. A man who trains monkeys to act in plays, used to 
purchase common kinds from the Zoological Society at the price 
of five pounds for each ; but he offered to give double the price, 

*^ 'The Variation of Animals and '' 'Annales des Sc. Nat.' (1st 

Plants under Domestication,' vol. i. Series), torn. xxii. p. 397. 
p. 27. 

74 The Descent of Man. Part I. 

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 tui'n out a good actor, he 
answered that it all depended on their power of attention. Jf, 
when he was talking and explaining anything to a monkey, its 
attention was easily distracted, as by a fly on the wall or other 
trifling object, the case was hopeless. If he tried by punishment 
to make an inattentive monkey act, it turned sulky. On the 
other hand, a monkey which carefully attended to him could 
always be trained. 

It is almost superfluous to state that animals have excellent 
Meinories for persons and places. A baboon at the Cape of Good 
Hope, as I have been informed by Sir Andrew Smith, recognised 
him with joy after an absence of nine months. I had a dog who 
was savage and averse to all strangers, and I purposely tried his 
memory after an absence of five years and two days. I went 
near the stable where he lived, and shouted to him in my old 
manner ; he shewed no joy, but instantly followed me out walk- 
ing, and obeyed me, exactly as if I had parted with him only 
half an hour before. A train of old associations, dormant during 
five years, had thus been instantaneously awakened in his mind. 
Even ants, as P. Huber ^^ has clearly shewn, recognised their 
fellow-ants belonging to the same community after a separation 
of four months. Animals can certainly by some means judge of 
the intervals of time between recurrent events. 

The Imagination is one of the highest prerogatives of man. 
By this faculty he unites former images and ideas, independently 
of the will, and thus creates brilliant and novel results. A poet, 
as Jean Paul Eichter 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 in- 
" voluntary art of poetry." The value of the products of our 
imagination depends of course on the number, accuracy, and 
clearness of our impressions, on our judgment and taste in 
selecting or rejecting the involuntary combinations, and to a 
certain extent on our power of voluntarily combining them. As 
dogs, cats, horses, and probably all the higher animals, even 
birds ^° have vivid dreams, and this is shewn by their movements 
and the sounds uttered, we must admit that they possess some 

'^ ' Les Mceurs des Fourmis,' 20 jyy Jerdon, * Birds of India,' 

1810, p. 150. vol. i. 1862, p. xxi. Houzeau says 

^^ Quoted in Dr. Maudsley's ' Phy- that his pavokeets and canary-birds 

siology and Pathology of Mind,' 18G8, dreamt: * Facultes Mentales/ torn, 

pp. 19, 220. ii. p. 13G. 

Chap. 111. Mental Poivcrs. 75 

power of imagination. There must be something special, which 
causes dogs to howl in the night, and especially during moonlight, 
in that remarkable and melancholy manner called baying. 
All dogs do not do so ; and, according to Houzcau,-^ they do not 
then look at the moon, but at some fixed point near the horizon. 
Houzeau thinks that their imaginations arc disturbed by tlie 
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 reasoning. 
Animals may constantly be seen to pause, deliberate, and resolve. 
It is a significant fiict, that the more the habits of any particular 
animal are studied by a naturalist, the more he attributes to 
reason and the less to unlearnt instincts.-^ In future chapters 
we shall see that some animals extremely low in the scale appar- 
ently display a certain amount of reason. No doubt it is often 
difficult to distinguish between the power of reason and that of 
instinct. For instance. Dr. Hayes, in his work on ' The Open 
Polar Sea,' repeatedly remarks that his dogs, instead of continu- 
ing to draw the sledges in a compact body, diverged and separ- 
ated when they came to thin ice, so that their weight might be 
more evenly distributed. This was often the first warning 
which the travellers received that the ice was becoming thin and 
dangerous. Kow, did the dogs act thus from the experience of 
each individual, or from the example of the older and wiser dogs, 
or from an inherited habit, that is from instinct ? This 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 Esquimaux dog, may 
have acquired an instinct, impelling them not to attack their 
prey in a close pack, when on thin ice. 

We can only judge by the circumstances under which actions 
are performed, whether they are due to instinct, or to reason, or 
to the mere association of ideas : this latter principle, however, 
is intimately connected with reason. A curious case has been 
given by Prof. Mobius,'''^ 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 

^* ' Facultes Mentales des Ani- I cannot help thinking, however, 

maux,' 1872, torn, ii, p. 181. that he goes too far in underrating 

^* Mr. L. H. Morgan's work on the power of Instinct. 
'The American Beaver,' 1868, offers -^ 'Die Bewegungou der Tliiere, 

a good illustration of this remark. &c., 187.'J, p. 11. 

76 The Descent of Man. Part I. 

catch tlie other fishes, that he was sometimes completely 
stunned. The pike went on thus for three months, but at last 
learnt caution, and ceased to do so. The plate of glass was then 
removed, but the pike would .not attack these particular fishes, 
though he would devour others which were afterwards intro- 
duced ; so strongly was the idea of a violent shock associated 
in his feeble mind with the attempt on his former neighboiu's. 
If a savage, who had never seen a large plate-glass window, 
were to dash himself even once against it, he would for a long 
time afterwards associate a shock with a window-frame ; but 
very differently from the pike, he would probably reflect on the 
nature of the impediment, and be cautious under analogous 
circumstances. Now with monkeys, as we shall presently see, a 
painful or merely a disagreeable impression, from an action once 
performed, is sometimes sufficient to prevent the animal from 
repeating it. If we attribute this difference between the monkey 
and the pike solely to the association of ideas being so much 
stronger and more persistent in the one than the other, though 
the pike often received much the more severe injury, can we 
maintain in the case of man that a similar difference implies the 
possession of a fundamentally different mind ? 

Houzeau relates ^^ that, whilst crossing a wide and arid plain 
in Texas, his two dogs suffered greatly from thirst, and that 
between thii'ty and forty times they rushed down the hollows 
to search for water. These hollows were not valleys, and there 
were no trees in them, or any other difference in the vegetation, 
and ^s they were absolutely diy there could have been no 
smell of damp earth. The dogs behaved as if they knew that 
a dip in the ground offered them the best chance of finding 
water, and Houzeau has often witnessed the same behaviour in 
other animals. 

I have seen, as I daresay have others, that when a small 
object is thrown on the ground beyond the reach of one of the 
elephants in the Zoological Gardens, he blows through his trunk 
on the ground beyond the object, so that the current reflected 
on all sides may drive the object within his reach. Again a well- 
known ethnologist, LIr. Westroj)p, informs me that he observed in 
Vienna a bear deliberately making with his paw a current in 
some water, which was close to the bars of his cage, so as to 
draw a piece of floating bread within his reach. These actions of 
the elephant and bear can hardly be attributed to instinct or 
inherited habit, as they would be of little use to an animal in a 
state of nature. Now, what is the difference between such 

2* 'Facultcs Mentales des Animaux,' 1872, torn. ii. p. 265. 

Chap. III. Mental Powers. 77 

actions, when performed by an uncultivated man, and by one of 
tlie higlier animals ? 

The savage and the dog have often found water at a low level, 
and the coincidence under such circumstances has become asso- 
ciated in their minds. A cultivated man would perhaps make 
some general proposition on the subject ; but from all that wc 
know of savages it is extremely doubtful whether tliey would do 
so, and a dog- certainly would not. But a savage, as well as a 
dog, would search in the same way, though frequently dis- 
appointed; and in both it seems to be equally an act of reason, 
whether or not any general proposition on the subject is 
consciously placed before the mind.^ The same would apply to 
tlie elephant and the bear making currents in the air or water. 
The savage would certainly neither know nor care by what law 
the desired movements were effected; yet his act would be 
guided by a rude process of reasoning, as surely as would a 
philosopher in his longest chain of deductions. There would no 
doubt be this difference between him and one of the higher 
animals, that he would . take notice of much slighter circum- 
stances and conditions, and would observe any connection 
between them after much less experience, and this would be of 
paramount importance. I kept a daily record of the actions of 
one of my infants, and when he was about eleven months old, 
and before he could speak a single word, I was continually 
struck with the greater quickness, with which all sorts of objects 
and sounds were associated together in his mind, compared with 
that of the most intelligent dogs I ever knew. But the higher 
animals differ in exactly the same way in this power of associa- 
tion from those low in the scale, such as the pike, as well as in 
that of drawing inferences and of observation. 

The promptings of reason, after very short experience, are well 
shewn by the following actions of American monkeys, which 
stand low in their order. Eengger, a most careful observer, 
states that when he flrst gave eggs to his monkeys in Paraguay, 
they smashed them, and thus lost much of their contents ; after- 
wards they gently hit one end against some hard body, and 
picked off the bits of shell with their fingers. After cutting 
themselves only once with any sharp tool, they would not toucli 
it again, or would handle it with the greatest caution. Lumps 
of sugar were often given them wi-apped up in paper; and 

-* Prof. Huxley has analysed with See his article, * Mr. Darwin's 

admirable clearness the mental steps Critics,' in the * Contemporary Ke- 

by which a man, as well as a dog, view,' Nov. 1871, p. 462, and in his 

arrives at a conclusion in a case ' Critiques and Essays,' 1873, p. 279. 
analogous to that given in my text. 

78 The Descent of Man. Part I. 

Eengger 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 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 jDartridges 
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 
" gTeatly puzzled, and after one or two trials, finding she could 
" not take it up without permitting the escape of the winged 
" bird, she considered a moment, then deliberately murdered it 
" by giving it a severe crunch, and afterwards brought away 
" both together. This was the only known instance of her 
" ever having wilfully injured any game." Here we have reason 
though not quite perfect, for the retriever might have brought 
the wounded bird first and then retui-ned for the dead one, as in 
the case of the two wild-ducks. I give the above cases, as 
resting on the evidence of two independent witnesses, and 
because in both instances the retrievers, after deliberation, 
broke through a habit which is inherited by them (that of not 
killing the game retrieved), and because they shew how strong 
their reasoning faculty must have been to overcome a fixed 

I will conclude by quoting a remark by the illustrious 
Humboldt.-^ " The muleteers in S. America say, ' I 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 expres- 
" sion, dictated by long experience, combats the system of 
" animated machines, better perhaps than all the arguments of 
" speculative philosophy." Nevertheless some wiiters even yet 
deny that the higher animals possess a trace of reason ; and they 
endeavour to explain away, by what appears to be mere 
verbiage,^^ all such facts as those above given. 

26 Mr. Belt, in his most interest- p. 45. Col. Hutchinson on ' Dog 
ing work, ' The Naturalist in IS'i- Breaking,' 1850, p. 46. 

caragua,' 1874 (p. 119), likewise ^^ ' Personal Karrative,' Eng. 

describes various actions of a tamed translat., vol. iii. p. 106. 

Cebus, which, I think, clearly shew ^^ I am glad to find that so acute 

that this animal possessed some a reasoner as Mr. Leslie Stephen 

reasoning power. (' Darwinism and Divinity, Essavs 

27 'The Moor and the Loch,' on Free-thinking,' 1873, p. 80), in 

Chap. II r. Menial Poiucrs. 79 

It has, I think, now been slicwn that man and the higher 
animals, especially the Primates, have some few instincts in 
commoift- All have the same senses, intuitions, and sensations, — 
similar passions, affections, and emotions, even the more complex 
ones, such as jealousy, suspicion, emulation, gratitude, and 
magnanimity ; they j)ractise deceit and arc revengeful ; they are 
sometimes susceptible to ridicule, and even have a sense of 
humour ; they feel wonder and curiosity ; they possess the same 
faculties of imitation, attention, deliberation, 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 
divided by an insuperable barrier from all the lower animals in 
his mental faculties. I formerly made a collection of above a 
score of such aphorisms, but they are almost worthless, as their 
wide difference and number prove the difficulty, if not the im- 
possibility, of the attempt. It has been asserted that man alone 
is capable of progressive improvement ; that he alone makes use 
of tools or fire, domesticates other animals, or possesses property; 
that no animal has the power of abstraction, or of forming 
general concepts, is self-conscious and comprehends itself ; that 
no animal employs language; that man alone has a sense of 
beauty, is liable to caprice, has the feeling of gratitude, mystery, 
&c.; believes in God, or is endowed with a conscience. I will 
hazard a few remarks on the more important and interesting of 
these points. 

Archbishop Sumner formerly maintained '^^ that man alone is 
capable of progressive improvement. That he is capable of 
incomj)arably greater and more rapid improvement than is any 
other animal, admits of no dispute; and this is mainly 
due to his power of speaking and handing down his acquired 
knowledge. With animals, looking first to the individual, every 
one who has had any experience in setting traps, knows that 

speaking of the supposed impassable " lures. It is diflicult to umU'r- 

barrier between the miuds of man " stand how anybody wiio has ever 

and the lower animals, says, "The " kept a dog, or seen an elephant, 

" distinctions, indeed, which have " can have any doubts as to an 

" been drawn, seem to us to rest " animal's power of performing tlio 

'• upon no better founJation than a " essential ]»rocesses of reasoning," 

" great many other metaphysical ^° See ' Gladness in Animals,' by 

" distinctions; that is, the assump- Dr. W. Lauder Lindsay, in 'Journal 

" tion that because you can give of Mental Science,' July 1871. 

" two things ditl'erent names, they " Quoted by Sir C. i^ycU, ' Auti- 

** must therefore have ditlerent na- quity of Man,' p. 497. 

'80 The Descent of Man. Part I. 

young animals can be caught much more easily than old ones ; 
and they can be much more easily approached by an enemy. 
Even with respect to old animals, it is impossible to catch" many in 
the same place and in the same kind of trap, or to destroy them 
by the same kind of poison ; yet it is improbable that all should 
have partaken of the poison, and impossible that all should have 
been caught in a trap. They must learn caution by seeing their 
brethren caught or poisoned. In North America, where the fur- 
bearing animals have long been pursued, they exhibit, according 
to the unanimous testimony of all observers, an almost incredible 
amount of sagacity, caution and cunning ; but trapping has been 
there so long carried on, that inheritance may possibly have come 
into play. I have received several accounts that when telegraphs 
are first set up in any district, many birds kill themselves by 
flying against the wires, but that in the course of a very few 
years they learn to avoid this danger, by seeing, as it would 
appear, their comrades killed.^^ 

If we look to successive genprations, or to the race, there is no 
doubt that birds and other animals gradually both acquire and 
lose caution in relation to man or other enemies ;^ and this 
caution is certainly in chief part an inherited habit or instinct, 
but in part the result of individual experience. A good observer, 
Leroy,^* 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 

Our domestic dogs are descended from wolves and jackals,^^ 
and though they may not have gained in cunning, and may have 
lost in wariness and suspicion, yet they have progressed in 
certain moral qualities, such as in affection, trust-worthiness, 
temper, and probably in general intelligence. The common rat 
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 

'2' For additional evidence, with - ^* ' Lettres Phil, sur I'lntelligence 

details, see M. Houzeau, ' Les des Animaux,' nouvelle e'dit. 1802, 

Facultes Mentales,' torn. ii. 1872, p. 86. 
p. 147. ^^ See the evidence on this head 

^' See, with respect to birds on in chap. i. vol. i. ' On the Variation 
oceanic islands, my ' Journal of of Animals and Plants under Do- 
Researches during the voyage of the mestication.' 

"Beagle,"' 1845, p. 398. 'Origin ^e c^^-qq, Zoolog. Soc' 1864, p. 

of Species,' 5th edit. p. 260. 186. 

CuAP. III. Mental Powers. 

exercise of all its faculties in avoiding extirpation b}^ man, as 
well as to nearly all the loss cunning or weak-minded rats having 
been continuously destroyed by him. It is, however, possible 
that the success of the common rat may be due to its having 
possessed greater cunning than its fellow-species, before it 
became associated with man. To maintain, independently of any 
direct evidence, that no animal during the course of ages has 
progressed in intellect or other mental faculties, is to beg the 
question of the evolution of siDccies. We have seen that, ac- 
cording to Lartet, existing mammals belonging to several orders 
have larger brains than their ancient tertiary prototypes. 

It has often been said that no animal uses any tool; but 
the chimpanzee m a state of nature cracks a native fruit, some- 
what like a wiilnut, with a stone.^ Rengger^^ easily taught an 
American monkey thus to break open hard palm-nuts ; and 
afterwards of its own accord, it used stones to open other kinds 
of nuts, as well as boxes. It thus also removed the soft rind of 
fruit that had a disagreeable flavour. Another monkey was 
taught to open the lid of a large box with a stick, and after- 
wards it used the stick as a lever to move heavy bodies ; and 1 
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 tamed 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 elejihant in a state ot 
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 emjiloyed 
as imjDlements ; but they are likewise used as weapons. Brehm'*° 
states, on the authority of the well-known traveller Schiniper, 
that in Abyssinia w^heu the baboons belonging to one species 
( C. ydada) descend in troops from the mountains to plunder the 
fields, they sometimes encounter 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. Erehm, when, accompanying the Duke of Coburg-Golha, 
aided in an attack with fire-arms on a troop of baboons in the 
pass of Mensa in Abyssinia. The baboons in return rolled so 
many stones down the mountain, some as large as a man's head, 
that the attackers had to beat a hasty retreat ; and the pass was 

^' Savage and Wyman in ' Boston 1830, s. 51-5G. 

Journal of Nat. Hist.' vol. iv. 1843- ^a 'pji^ 'Indian iMeld,' iMarch 4, 

44, p. 383. 1871. 

'« 'Sau'-ethiere von Paracruav,' *<> ' ThiorlcdxMi,' P.. i. s. 79, 82. 

82 The Descent of Man. Tart I. 

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, accompanied by their 
young, " breaking off branches and the great spiny fruit of the 
" Durian tree, with every appearance of rage; causing such a 
" shower of missiles as effectually kept us from approaching too 
" near the tree." As I have repeatedly seen, a chimpanzee will 
throw any object at hand at a person who offends him ; and the 
before mentioned baboon at the Cape of Good Hope prepared 
mud for the purpose. 

In the Zoological Gardens, a monkey, which had weak teeth, 
used to break open nuts with a stone ; and I was assui'ed 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 immeasiu'able gulf between 
him and the brutes. This is no doubt a very important dis- 
tinction ; but there appears to me much truth in Sir J. Lubbock's 
suggestion,'^ that when primeval man first used flint-stones for 
any purpose, he would have accidentally splintered them, and 
would then have used the sharp fragments. From this step it 
would be a small one to break the tlints 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 elai^sed before the men of the 
neolithic period took to grinding and polishing their stone tools. 
In breaking the flints, as Sir J. Lubbock likewise remarks, 
sparks would have been emitted, and in grinding them heat 
would have been evolved: thus the two usual methods of 
" obtaining fire may have originated." The nature of fire would 
have been known in the many volcanic regions where lava 
occasionally flows through forests. The anthropomoriihous 
apes, guided probably by instinct, build for themselves tem- 
porary platforms ; but as many instincts are largely controlled 
by Teason, the simpler ones, such as this of buildiog a platform, 
might readily pass into a voluntary and conscious act. The 
orang is known to cover itself at night with the leaves of the 
Pandanus ; and Brehm states that one of his baboons used to 
protect itself from the heat of the sun by throwing a straw-mat 

41 'The Malay Archipelago,' vol. 14-5,147. 
1. -1869. p. 87. ■'^ ' Trehistoric Times,' 1865, p. 

« ' Primeval Mau,' 1869, pp. 473, &c 

Chap. II r. Mental Powers. %i 

over its head. In tliese several habits, we probably see the first 
steps towards some of the simpler arts, such as rude architecture 
and dress, as they arose amongst the early progenitors of man. 

Abstraction, General Conceptions, ^elf -consciousness, Mtntd 
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 wliich 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 I say to my terrier, in an 
eager voice (and I have made the trial many times), " Hi, hi, 
where is it ? " she at once takes it as a sign that something is to 
be hunted, and generally first looks quickly all around, and 
then rushes into the nearest thicket, to scent for any game, but 
finding nothing, she looks up into any neighbouring tree for a 
squirrel. Now do not these actions clearly shew that she had in 
lier mind a general idea or concept that some animal is to bo 
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 deatli, 
and so forth. But how can we feel sure that an old dog with an 
excellent memory and some power of imagination, as shewn by 
his dreams, never reflects on his past pleasures or pains in the 
chase ? And this would be a form of self-consciousness. On tlie 
other hand, as Buchner^^ 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- 
consciousness, or reflect on the nature of her own existence. It 
is generally admitted, that the higher animals possess memory, 

** ^Ir. Hookham, in a lettei- to *^ 'Conferences sui- la Tli(^orie 

Prof. Max Miiller, in the ' Biimiug- Darwinienne,' French translat. 
ham News,' May 1873. 18f;9, p. 1:52. 

84 The Descent of Man. Past I. 

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 comj^lex faculties, such as the higher forms of abstraction, 
and self-consciousness, &c., having been evolved through the 
development and combination of the simpler ones. It has been 
urged against the views here maintained, that it is impossible 
to say at what point in the ascending scale animals become 
capable of abstraction, &c. ; but who can say at what age this 
occurs in our young children ? We see at least that such powers 
are developed in children by imperceptible degrees. 

That animals retain their mental individuality is unquestion- 
able. When my voice awakened a train of old associations in 
the mind of the before-mentioned dog, he must have retained 
his mental individuality, although every atom of his brain had 
probably undergone change more than once during the interval 
of five years. This dog might have brought forward the 
argument lately advanced to crush all evolutionists, and said, 
" I abide amid all mental moods and all material changes. . . . 
" The teaching that atoms leave their impressions as legacies to 
'' other atoms falling into the places they have vacated is con- 
" tradictory of the utterance of consciousness, and is therefore 
'' false ; but it is the teaching necessitated by evolutionism, con- 
'' sequently the hypothesis is a false one."'^*^ 

Language. — This faculty has justly been considered as one of 
the chief distinctions between man and the lower animals. But 
man, as a highly competent judge, Archbishop Whately remarks, 
" is not the only animal that can make use of language to express 
" what is passing in his mind, and can understand, more or less, 
"what is so expressed by another."^' In Paraguay the Cebus, 
azaroi when excited utters at least six distinct sounds, which 
excite in other monkeys similar emotions."^^ The movements of 
the features and gestures of monkeys are understood by us, and 
they joartly understand ours, as Pengger and others declare. It 
is a more remarkable fact that the dog, since being domesticated, 
has learnt 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 

*^ The Rev. Dr. J. M'Canu, ' Auti- "^ Rengger, ibid. s. 45. 

Darwinism,' 1869, p. 13. ^^ See mj 'Variation of Ani- 

*'' Quoted in 'Anthropological Re- mak- and Plants under Domestica- 

view ' 18.'34, p. 158. tion,' vol. i. p. 27. 

Ch ap. III. Mental Powers. 8 5 

when starting on a walk with his master ; and the very distinct 
one of demand or snppheation, as when wishing for a door or 
window to be opened. According to Houzean, who paid par- 
ticular attention to the subject, the domestic fowl utters at least 
a dozen significant sounds.^*^ 

The habitual use of articulate language is, however, iieculiar 
to man ; but he uses, in common with the lower animals, inarti- 
culate cries to express his meaning, aided by gestures and the 
movements of the muscles of the face/'^ This especially holds 
good with the more simple and vivid feelings, which are but 
little connected with our higher intelligence. Our cries of pain, 
fear, surprise, anger, together with tlieir appropriate actionS; 
and the murmur of a mother to her beloved child, are more 
expressive than any words. That which distinguishes man 
from the lower animals is not the understanding of articulate 
sounds, for, as every one knows, dogs understand many words 
and sentences. In this respect they are at the same stage of 
development as infants, between the ages of ten and twelve 
months, who understand many words and short sentences, but 
cannot yet utter a single word. It is not the mere articulation 
which is our distinguishing character, for parrots and other 
birds possess this power. Nor is it the mere capacity of con- 
necting definite sounds with definite ideas ; for it is certain that 
some parrots, which have been taught to speak, connect un- 
erringly words with things, and persons with events.^^ The 
lower animals differ from man solely in his almost infinitely 
larger power of associating together the most diversified 

*• 'Facultes Meutales des Ani- to add to the "good morning" a 

maux,' torn. ii. 1872, p. 346-349. short sentence, which was nevcM- 

^^ See a discussion on this subject once repeated after his father's 

in Mr. E. B. Tylor's very interesting death. He scolded violently a 

work, ' Researches into the Early strange dog which came into the 

History of Mankind,' 18(35, chaps. room through the open window; 

ii. to iv. and he scolded another parrot (say- 

" I have received several detailed ing "you naughty polly ") which 

accounts to this effect. Admiral had got out of its cage, and was 

Sir J. Sulivan, whom I know to be eating apples on the kitchen table, 

a careful observer, assures me that See also, to the same elfect, Houzeau 

an African parrot, long kept in his on parrots, ' Facultes Mentales,' 

lather's house, invariably called torn, ii, p. 309. Dr. A. Moschkau 

certain persons of the household, as informs me that he knew a starling 

well as visitors, by their names. He which never made a mistake in 

said "good morning" to every one at saying in German " good morning " 

breakfast, and "good night " to each to persons arriving, and " good- 

as they left the room at night, and bye, old follow," to those departing, 

never reversed these salutations. I could add several other such 

To Sir J. Sulivan's father, he used cases. 

86 TJie Descent of Man. Paet L 

sounds and ideas; and this obviously depends on the high 
development of his mental powers. 

As Home Took, one of the founders of the noble science of 
philology, observes, language is an art, like brewing or baking ; 
but writing would have been a better simile. It certainly is not 
a true instinct, for every language has to be learnt. It differs, 
however, widely from all ordinary arts, for man has an in- 
stinctive tendency to speak, as we see in the babble of our 
young children ; whilst no child has an instinctive tendency to 
brew, bake, or write. Moreover, no philologist now supposes 
that any language has been deliberately invented ; it has been 
slowly and unconsciously developed by many steps.^^ The 
sounds uttered by birds offer in several respects the nearest 
analogy to language, for all the members of the same species utter 
the same instinctive cries expressive of their emotions ; and all 
the kinds which sing, exert their power instinctively; but the 
actual song, and even the call notes, are learnt from their 
parents or foster-imrcnts. 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 imperfect 
" endeavour in a child to babble." The young males continue 
practising, or as the bird-catchers say, " recording," for ten or 
eleven months. Their first essays show hardly a rudiment of 
the future song ; but as they grow older we can perceive what 
they are aiming at ; and at last they are said " to sing their 
" song round." Nestlings which have learnt the song of a distinct 
species, as with the canary-birds educated in the Tyrol, teach 
and transmit their 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 provincial dialects ;" and the songs of allied, 
though distinct species may be compared with the languages of 
distinct races of man. I have given the foregoing details to 
shew that an instinctive tendency to acquire an art is not 
peculiar to man. 

With respect to the origin of articulate language, after having 
read on the one side the highly interesting works of Mr. Hens- 

^^ See some good remarks on this " gards the immediate end to be 

head by Prof. Whitney, in his " attained ; unconsciously as regards 

' Oriental and Linguistic Studies,' " the further consequences of the 

1873, p. 354. He observes that the " act." 

desire of communication between ^^ Hon. Daines Barrington in 

man is the living force, which, ' Philosoph. Transactions,' 1773, p. 

in the development of language, 262. See also Dureau de la Malle, 

" works both consciously and un- in * Ann. des. Sc. Nat.* 3rd series, 

" consciously; consciously as re- Zoolog. torn. x. p. 119. 

Chap. 111. Mental Poivers. 87 

leigh Wedgwood, the Eev. F. Farrar, and Prof. Schleicher,^^ and 
the celebrated lectures of Prof. Max Mtiller 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 instinctive cries, aided by signs and 
gestures. AVhen we treat of sexual selection we shall sec that 
primeval man, or rather some early progenitor of man, probably 
first used his voice in producing true musical cadences, that is 
in singing, as do some of the gibbon-apes at the present day ; 
and we may conclude from a widely-spread analogy, that this 
power would have been especially exerted during the courtship 
of the sexes, — would have expressed various emotions, such as 
love, jealousy, triumph, — and would have served as a challenge to 
rivals. It is, therefore, probable that the imitation of musical 
cries by articulate sounds may have given rise to words expres- 
sive of various complex emotions. The strong tendency in our 
nearest allies, the monkeys, in microcephalous idiots,"^'^ and in 
the barbarous races of mankind, to imitate whatever they hear 
deserves notice, as bearing on the subject of imitation. Since 
monkeys certainly understand much that is said to them by 
man, and when wild, utter signal-cries of danger to their 
fellows ; ^^ and since fowls give distinct warnings for danger on 
the gi-ound, or in the sky from hawks (both, as well as a third 
cry, intelligible to dogs),^*^ may not some unusually wise ape-like 
animal have imitated the growl of a beast of prey, and thus 
told his fellow-monkeys the nature of the expected danger ? This 
would have been a first step in the formation of a language. 

As the voice was used more and more, the vocal organs would 
have been strengthened and perfected through the principle of 
the inherited effects of use ; and this would have reacted on the 
power of speech. But the relation between the continued use of 
language and the development of the brain, has no doubt been 
far more important. The mental powers in some early pro- 
genitor of man must have been more highly developed than in 

" <0n the Origin of Language,' ^e y^g^^ * Memoire sur les Micro- 

by H. Wedgwood, 18GG. 'Chapters cephales,' 1867, p. 1(39. With re- 

on Language,' by the Rev. F. W. spect to savages, I have given some 

Farrar, 1865. These works are facts in my ' of llesearches,' 

most interesting. See also ' De la &c., 1845/p. 206. 
Phys. et de i'arole,' par Albert ^7 g^g ^.\^,.^y^. evidence on this head 

Lemoine, 1865, p. 190. The work in the two works so often quoted, 

on this subject, by the Lite Prot". by Brehm and Ilunggei-. 
Aug. Schleicher, has been translated ^^ Houzeau gives a very curious 

by Dr. Bikkers into English, under account of his oljservations on *liis 

the title of ' Darwinism tested by subject in liis ' Facultes Meutales 

the Science of Language,' 1869 dcs Aniniaux,' toni. ii., p. 348. 

88 The Descent of Man. Part I. 

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 Avould 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 ajopears, also, that even an ordinary train 
of thought almost requires, or is greatly facilitated by some 
form of language, for the dumb, deaf, and blind girl, Laura 
Bridgman, was observed to use her fingers whilst dreaming.^^ 
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 certain extent, manifestly without the aid of language. 
The intimate connection between the brain, as it is now 
developed in us, and the faculty of speech, is well shewn by 
those curious cases of brain-disease in which speech is specially 
affected, as when the power to remember substantives is lost, 
whilst other words can be correctly used, or where substantives 
of a certain class, or all except the initial letters of substantives 
and i^roper names are forgotten.^ There is no more improb- 
ability in the continued use of the mental and vocal organs 
leading to inherited changes in their structure and functions, 
than in the case of handwriting, which depends partly on the 
form of the hand and partly on the disposition of the mind ; and 
hand- writing is certainly inherited.''^ 

Several writers, more especially Prof. Max Muller,^^ have 
lately insisted that the use of language implies the power of 
forming general concepts ; and that as no animals are supposed 
to possess this power, an impossible barrier is formed between 
them and man.*^^ With respect to animals, I have already 

53 See remarks on tins head by ^- Lectures on 'Mr. Darwin's Phi- 

Dr. Maudsley, 'The Physiology and losophy of Language,' 1873. 

Pathology of Mind,' 2ud edit. 1868, ^'^ The judgment of a distin- 

p. 199. guished philologist, such as Prof. 

^^ Many curious cases have been Whitney, will have far more weight 

recorded. See, for instance, Dr. on this point than anything that 

Bateman 'On Aphasia,' 1870, p. 27, I can say. He remarks ('Oriental 

31, 53, 100, &c. Also, 'Inquiries and Linguistic Studies,' 1873, p.. 

Concei-ning the Intellectual Powers,' 297), in speaking of Bleek's views : 

by Dr. Abercrombie, 1838, p. 150. "Because on the grand scale lan- 

^^ 'The Variation of Animals " guage is the necessary auxiliary 

and Plants under Domestication,' " of thought, indispensable to tlie 

vol. ii. p. 6. " development of the power of 

Chap. II r. Mental Pozvc7'S, 89 

endeavoured to show that they have this power, at least in a 
riule and incipient degree. As for as concerns infants of from 
ten to eleven months old, and deaf-mutes, it seems to mo in- 
credible, that they should be able to connect certain sounds with 
certain general ideas as quickly as they do, unless such ideas 
were already formed in their minds. The same remark may be 
extended to the more intelligent animals ; as Mr. Leslie Stephen 
observes,'^'* " A dog frames a general concept of cats or sheep, 
" and knows the corresponding words as well as a philosopher. 
" And the capacity to understand is as good a j^roof of vocal 
" intelligence, 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 antennjc, as shewn by 
Huber, who devotes a whole chapter to their language. We 
might have used our fingers as efficient instruments, for a 
person with practice can report to a deaf man every word of a 
speech rapidly delivered at a public meeting; but the loss of 
our hands, whilst thus employed, would have been a serious 
inconvenience. As all the higher mammals possess vocal organs, 
constructed on the same general plan as ours, and used as a 
means of communication, it was obviously probable that these 
same organs would be still further developed if the power of 
communication had to be improved ; and this has been cftected by 
the aid of adjoining and well adapted parts, namely the tongue 
and lips.^5 The fact of the higher apes not using their vocal 
organs for speech, no doubt depends on their intelligence not 
having been sufficiently advanced. The possession by them of 

" thinking, to the distinctness and " fingers into imitation of spoken 

" variety and complexity of cogni- " words." Jlax Miillcr gives in 

" tions to the full mastery of con- italics ('Lectures on ]\Jr. Darwin's 

'• sciousness ; therefore he woukl Philosophy of Language,' 187.'>, 

" fain make thought absolutely im- third lecture) the following aphor- 

" possible without speech, identify- ism: "There is no thought with- 

" ing the faculty with its instru- " out words, as little as tiiere are 

" ment. He might just as reason- " words without thought." What 

" ably assert that the liuman hand a strange definition must here be 

" cannot act without a tool. With gi\-cn to the word thought ! 

" such a doctrine to start from, he ^^ ' Essays on Free-thinking,' tS;c., 

" cannot stop short of IMiiiler's 1873, p. 82. 

" worst paradoxes, that an infant ^^ See some ggod remarks to this 

" (m /«»5, not speaking) is not a effect by Dr. Maudslcy, ' The I'hy- 

•* human being, and that deaf-mutes siology and Pathology of Mind,' 

" do not become possessed of reason 18G8, p. l'J9. 
" until tliey learn to twist their 

90 ' The Descent of Man. Part 1. 

organs, wliicli with long- continued practice might have been 
used for speech, although not thus used, is paralleled by the 
case of many birds which possess organs fitted for singing, 
though they never sing. Thus, the nightingale and crow have 
vocal organs similarly constructed, these being used by the 
former for diversified song, and by the latter only for croaking.*^' 
If it be asked why apes have not had their intellects developed 
to the same degree as that of man, general causes only can be 
assigned in answer, and it is unreasonable to expect anything 
more definite, considering our ignorance with respect to the 
successive stages of development through which each creature 
has passed. • 

The formation of different languages and of distinct species, 
and the proofs that both have been developed through a gradual 
process, are curiously parallel.^^ But we can trace the formation 
of many words further back than that of species, for we can 
perceive how they actually arose from the imitation of various 
sounds. We find in distinct languages striking homologies duo 
to community of descent, and analogies due to a similar process 
of formation. The manner in which certain letters or sounds 
change when others change is very like correlated growth. We 
have in both cases the reduplication of parts, the effects of long- 
continued use, and so forth. The frequent presence of rudi- 
ments, both in languages and in species, is still more remarkable. 
The letter m in the word am, means / ; so that in the expres- 
sion / am, a superfluous and useless rudiment has been retained. 
In the spelling also of words, letters often remain as the rudi- 
ments of ancient forms of pronunciation. Languages, like 
organic beings, can be classed in groups under groups ; and they 
can be classed either naturally according to descent, or arti- 
ficially by other characters. Dominant languages and dialects 
spread widely, and lead to the gradual extinction of other^ 
tongues. A language, like a species, when once extinct, never, 
as Sir C. Lyell remarks, reappears. The same language never 
has two birth-places. Distinct languages may be crossed or 
blended together.''^ We see variability in every tongue, and new 

^^ Macgillivray, ' Hist, of British display any -anusual capacity for 

Birds,' A'ol. ii. 1839, p. 29. An imitation. ' Researches in Zoology,' 

excellent observer, Mr. Blackwall, 1834, p. 158. 

remarks that the magpie learns to ''^ See the very interesting pa- 
pronounce single words, and even rallelism between the development 
short sentences, more readily than of species and languages, given by 
almost any other British bird ; yet, Sir C. Lyell in ' The Geolog. Evi- 
as he adds, after long and closely dences of the Antiquity of Man,' 
investigating its habits, he has 1863, chap, xxiii. 
Lever known it, in a state of nature, ^^ See remarks to this effect by 

CiLvp. III. Mental Powers, • 91 

words are continually cropping np ; but as there is a limit to 
the powers of the memory, single words, like whole languages, 
gradually become extinct. As Max Miiller'^^ has well re- 
marked : — ''' A struggle for life is constantly going on amongst 
*Hhe words and grammatical forms in each language. The 
" better, the shorter, the easier forms are constantly gaining the 
" upper hand, and they owe their success to their own inherent 
" virtue." To these more important causes of the survival of 
certain words, mere novelty and fashion may be added ; for 
there is in the mind of man a strong love for slight changes in all 
things. The survival or preservation of certain favoured words 
in the struggle for existence is natural selection. 

The perfectly regular and wonderfully complex construction 
of the languages of many barbarous nations has often been 
advanced as a proof, either of the divine origin of these lan- 
guages, or of the high art and former civilisation of their 
founders. Thus F. von Schlegel writes : " In those languages 
" which appear to be at the lowest grade of intellectual culture, 
*' we frequently observe a very high and elaborate degree of art 
"in their gi-ammatical structure. This is especially the case 
" with the Basque and the Lapponian, and many of the Ame- 
" rican languages.'"''® But it is assuredly an error to speak of 
any language as an art, in the sense of its having been elabor- 
ately and methodically formed. Philologists now admit that 
conjugations, declensions, &c., originally existed as distinct 
words, since joined together; and as such words express the 
most obvious relations between objects and persons, it is not 
surprising that they should have been used by the men of most 
races during the earliest ages. With respect to perfection, the 
following illustration will best shew how easily we may err : a 
Crinoid sometimes consists of no less than 150,000 pieces of 
shell,'^ all arranged with i^erfect symmetry in radiating lines ; 
but a naturalist does not consider an animal of tliis kind as 
more perfect than a bilateral one with comparatively few jDarts, 
and with none of these parts alike, excepting on the opposite sides 
of the body. He justly considers the differentiation and special- 
isation of organs as the test of perfection. So with languages ; 
the most symmetrical and complex ought not to be ranked above 
irregular, abbreviated, and bastardised languages, which have 

the Rev. F. W. Fanar, in an in- '« Quoted by C. S. Wake, ' Cliap- 

terostiiig article, eutitleJ ' Philo- ters on Mau,' 1868, p. 101, 
logy and Darwinism' in 'Nature,' '' Buckland, 'Bridgewatcr Trca- 

March 2-tth, 1870, p. 528.' p. 411. 
«3 ' Nature,' Jan. tith, 1870, p. 2:)7. 

92 The Descent of Man. Part I. 

borrowed expressive words and useful forms of construction from 
various conquering, conquered, or immigrant races. 

From these few and imperfect remarlis I conclude tliat 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 insuperable objection to 
the belief that man has been developed from some lower 

Bense of Beauty. — This sense has been declared to be peculiar 
to man. I refer here only to the pleasure given by certain 
colours, forms, and sounds, and which may fairly be called a 
sense of the beautiful ; with cultivated men such sensations arc, 
however, intimately associated with complex ideas and trains of 
thought. When we behold a male bird elaborately displaying 
his graceful plumes or splendid colours , before the female, 
whilst other birds, not thus decorated, make no such display, 
it is impossible to doubt that she admires the beauty of her 
male partner. As women everywhere deck themselves with 
these plumes, the beauty of such ornaments cannot be disputed. 
As we shall see later, the nests of humming-birds, and the 
playing passages of bower-birds are tastefully ornamented 
with gaily-coloured objects; and this shews that they must 
receive some kind of pleasure from the sight of such things. 
With the great majority of animals, however, the taste for the 
beautiful is confined, as far as we can judge, to the attractions 
of the opposite sex. The sweet strains poured forth by many 
male birds during the season of love, are certainly admired by 
the females, of which fact evidence will hereafter be given. If 
female birds had been incapable of appreciating the beautiful 
colours, the ornaments, and voices of their male partners, all the 
labour and anxiety exhibited by the latter in disi^laying their 
charms before the females would have been thrown away ; and 
this it is impossible to admit. Why certain bright .colours 
should excite pleasure cannot, I presume, be explained, any 
more than why certain flavours and scents are agreeable ; but 
habit has something to do with the result, for that which is at 
first unpleasant to our senses,' ultimately becomes pleasant, and 
habits are inherited. With respect to sounds, Helmholtz has 
explained to a certain extent on physiological principles, why 
harmonies and certain cadences are agreeable. But besides 
this, sounds frequently recurring at irregular intervals are 

''- Soe some gooil remarks on the J. Lubbock, 'Origin of Civilisatiou,* 
simplification of languages^ by Sir 1870, p. 278. 

CuAp. 111. Mental Powers, 93 

highly disagreeable, as every one will admit who has listened at 
night to the irregular flapping of a rope on board ship. The 
same princii^le seems to come into play with vision, as the 
eye prefers symmetry or figures with some regular recurrence. 
Patterns of this kind are employed by even the lowest savages 
as ornaments; and they have been developed through sexual 
selection for the adornment of some male animals. Whether we 
can or not give any reason for the pleasure thus derived from 
vision and hearing, yet man and many of the lower animals are 
alike pleased by the same colours, graceful shading and forms, 
and the same sounds. 

The taste for the beautiful, at least as far as female beauty is 
concerned, is not of a special nature in the human mind ; for it 
differs widely in the different races of man, and is not quite the 
same even in the different nations of the same race. Judging 
from the hideous ornaments, and the equally hideous music 
admired by most savages, it might be urged that their jesthetic 
faculty was not so highly developed as in certain animals, for 
instance, as in birds. Obviously no animal would be capable of 
admiring such scenes as the heavens at night, a beautiful land- 
scape, or refined music; but such high tastes are acquired 
through culture, and depend on complex associations ; they are 
not enjoyed by barbarians or by uneducated persons. 

Many of the faculties, which have been of inestimable service 
to man for his progressive advancement, such as the powers of 
the imagination, wonder, curiosity, an undefined sense of beauty, 
a tendency to imitation, and the love of excitement or novelty, 
could hardly fail to lead to capricious changes of customs and 
fashions. I have alluded to this point, because a recent writer '^ 
has oddly fixed on Caprice " as one of the most remarkable and 
"typical differences between savages and brutes." But not 
only can we partially understand how it is that man is from 
various conflicting influences rendered capricious, but that 
the lower animals are, as we shall hereafter see, likewise capri- 
cious in their affections, aversions, and sense of beauty. There 
is also reason to suspect that they love novelty, for it own sake. 

Bdief in God — BeJiyirm. — 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 

" 'The Spectator,' Dec. -tth, 1SG9, p. 1430. 

94 The Descent of Man. Part I. 

words in their languages to express snch an idea/* The question 

is of course wholly distinct from that higher one, whether there 
exists a Creator and Euler of the universe ; and this has been 
answered in the affirmative by some of the highest intellects that 
have ever existed. 

If, however, we include under the term " religion '' the belief 
in miseen or spiritual agencies, the case is wholly different ; for 
this belief seems to be universal with the less civilised races. 
Nor is it difficult to comprehend how it arose. As soon as the 
important faculties of the imagination, wonder, and curiosity, 
together with some power of reasoning, had become partially 
developed, man would naturally crave to understand what was 
passing around him, and would have vaguely speculated on his 
own existence. As Mr. M'Lennan'^ has remarked, " Some explan- 
" ation of the phenomena of life, a man must feign for himself; 
" and to judge from the universality of it, the simplest hypothesis, 
" and the first to occur to men, seems to have been that natural 
" phenomena are ascribable to the presence in animals, plants, 
" and things, and in the forces of nature, of such spirits prompting 
" to action as men are conscious they themselves possess." It 
is also probable, as Mr. Tylor has shewn, that dreams may have 
first given rise to the notion of spirits ; for savages do not readily 
distinguish between subjective and objective impressions. When 
•a savage dreams, the figures which appear before him arc 
believed to have come from a distance, and to stand over him ; 
or " the soul of the dreamer goes out on its travels, and comes 
" home with a remembrance of what it has seen."^^" But until 

^■* See an excellent article on this forms of religious belief throughout 
subject by the Re\^. F. W. Farrar, the world, by man being led through 
in the 'Anthropological Review,' dreams, shadows, and other causes, 
Aug. 1864, p. ccxvii. For further to look at himself as a double 
facts see Sir J. Lubbock, ' Pre- essence, corporeal and spiritual. As 
historic Times,' 2nd edit. 1869, p. the spiritual being is supposed to 
.564 ; and especially the chapters on exist after death and to be power- 
Religion in his 'Origin of Civilisa- ful, it is propitiated by various gifts 
tion,' 1870. and ceremonies, and its aid involved. 

"''" ' The Worship of Animals and He then further shews that names 

Plants,' in the ' Fortnightly Review,' or nicknames given from some 

Oct. 1, 1869, p. 422. animal or other object, to the early 

"^ Tylor, ' Early History of Man- progenitors or founders of a tribe, 

kind,' 1865, p. 6. See also the arc supposed after a long interval 

three striking chapters on the De- to represent the real progenitor of 

velopment of Religion, in Lubbock's the tribe; and such animal or object 

' Origin of Civilisation,' 1870. In a is then naturally believed still to 

like manner Mr, Herbert Spencer, exist as a spirit, is held sacred, and 

in his ingenious essay in the ' Fort- worshipped as a god. Nevertheless 

nightly Review' (May 1st, 1870, I cannot but suspect that there is 

p. 535), accounts for the earliest a still earlier and ruder stage, when 

Chap. II f. Mental Powers, 95 

the faculties of imagination, curiosity, reason, &c., had been 
fairly well developed in the mind of man, his dreams would not 
have led him to believe in s^Dirits, any more than in the case of 
a dog. 

The tendency in savages to imagine that natural objects and 
agencies are animated by spiritual or living essences, is perha]')s 
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 
liot and still day ; but at a little distance a slight breeze occa- 
sionally moved an open parasol, which would have been wholly 
disregarded by the dog, had any one stood near it. As it was, 
every time that the parasol slightly moved, the dog growled 
fiercely and barked. He must, I think, have reasoned to himself 
in a rapid and unconscious manner, that movement without any' 
apparent cause indicated the presence of some strange living 
agent, and that no stranger had a right to be on his territory. 

The belief in spiritual agencies would easily pass into the 
belief in the existence of one or more gods. For savages would 
naturally attribute to spirits the same passions, the same love of 
vengeance or simplest form of justice, and the same affections 
which they themselves feel. The Fuegians appear to be in this 
respect in an intermediate condition, for when the surgeon on board 
the "Beagle" shot some young ducklings as specimens, York 
Minster declared in the most solemn manner, " Oh, Mr. Bynoe, 
" much rain, much snow, blow much ;" and this was evidently 
a retributive punishment for wasting human food. So again he 
related how, when his brother killed a " wild man," storms long 
raged, much rain and snow fell. Yet we could never discover 
that the Fuegians believed in what we should call a God, or 
practised any religious rites ; and Jemmy Button, with justifiable 
pride, stoutly maintained that there was no devil in his land. 
This latter assertion is the more remarkable, as with savages the 
belief in bad spirits is far more common than that in good 

The feehog 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 cxiDcricnce so complex an emotion 

anything which manifests power or ^^ See an able article on the 

movement is thought to be endowed ' Physical Elements of ileligion,' by 

with some form of life, and with !Mr. L. Owen Pike, in ' Anthropolog. 

mental faculties analogous to our Kevicw,' April, 1870, p. Ixiii. 

g6 The Desceitt of Man. Tart I, 

until advanced in his intellectual and moral faculties 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 submission, some fear, and 
perhaps other feelings. The behaviour of a dog when returning 
to his master after an absence, and, as I may add, of a monkey 
to his beloved keeper, is widely diiferent from that towards their 
fellows. In the latter case the transports of joy appear to be 
somewhat less, and the sense of equality is shewn in every action. 
Professor Braubach goes so far as to maintain that a dog looks 
on his master as on a god.^^ 

The same high mental faculties which first led man to believe 
in miseen spiritual agencies, then in fetishism, polytheism, and 
ultimately in monotheism, would infallibly lead him, as long as 
his reasoning powers remained poorly developed, to various 
strange superstitions and customs. Many of these are terrible 
to think of — such as the sacrifice of human beings to a blood- 
loving god ; the trial of innocent persons by the ordeal of poison 
or fire ; witchcraft, &c. — yet it is well occasionally to reflect on 
these superstitions, for they shew us what an infinite debt of 
gratitude we owe to the improvement of our reason, to science, 
and to our accumulated knowledge. As Sir J. Lubbock''^ has well 
observed, " it is not too much to say that the horrible dread of 
" unknown evil hangs like a thick cloud over savage life, and 
" embitters every pleasure." These miserable and indirect 
consequences of our highest faculties may be compared with the 
incidental and occasional mistakes of the instincts of the lov/er 

^* ' Religion, Moral, &c., del* Dar- ^^ 'Prehistoric Times,' 2iid edit, 

win'schen Art-Lehre,' 1869, s. 53. p. 571. In this work (p. 571) 

It is said (Dr. W. Lauder Lindsay, there will be found an excellent 

'Journal of Mental Science,' 1871, account of the many strange and 

p. 43), that Bacon long ago, and the capricious customs of savages, 
poet Burns, held the same notion. 

Chap. IV. Moral Sense. 97 


CoMrAEisoN OF THE Mental Powers of Man and the 
Lower Animals— co??^mz(ecZ. 

Thf moral sense — Fundamental proposition — The qualities of social 
animals — Origin of sociability — Strutrgle between op])osed instincts — 
Man a social animal — Tlie more enduring social instincts conquer otlicr 
less persistent instincts — The social virtues alone regarded by savages — 
The self-regarding virtues acquired at a later stage of development — 
The importance of the judgment of the members of the same community 
on conduct — Transmission of moral tendencies — Summary. 

I FULLY subscribe to the judgment of those writers^ who 
maintain that of all the differences between man and the 
lower animals, the moral sense or conscience is by far the 
most important. This sense, as Mackintosh^ remarks, " has a 
" rightful supremacy over every other principle of human 
" action ;" it is summed up in that short but imperious word 
ouglit, so full of high significance. It is the most noble of all 
the attributes of man, leading him without a moment's hesita- 
tion to risk his life for that of a fellow-creature ; or after due 
deliberation, impelled simply by the deep feeling of right or 
duty, to sacrifice it in some great cause. Immanucl Kant 
exclaims, " Duty ! Wondrous thought, that workest neither by 
" fond insinuation, flattery, nor by any threat, but merely by 
" holding np thy naked law in the soul, and so extorting for 
" thyself always reyerence, if 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 in- 

* See, for instance, on this subject, and Moral Science,' 18G8, p. 543- 
Quatrefages, ' Llnite de i'Espece 725) of twenty-six British authors 
Humaine,' 1861, p. 21, &c. who have written on this subject, 

- ' Dissertation on Ethical Philo- and whose names are familiar to 

sophy,' 1837, p. 231, &c. every reader ; to these, ^Ir. Bain's 

' ' Metaphysics of Ethics,' trans- own name, and those of Mr. Lecky, 

lated by J. W. Semple, Edinburgh, Mr, Shadworth Hodgson, Sir J. 

1836, p. 136. Lubbock, and others, mi|ht be 

* Mr. Bain gives a list (' Mental added. 

98 The Descent of Man, Paet 1. 

dependent 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 folio v\dng proposition seems to me in a high degree 
probable — namely, that any animal whatever, endowed with 
well-marked social instincts,^ the parental and filial affections 
being here included, would inevitably acquire a moral sense or 
conscience, as soon as its intellectual powers had become as well, 
or nearly as well developed, as in man. For, firstly, the social 
instincts lead an animal to take pleasure in the society of its 
fellows, to feel a certain amount of sympathy with them, and to 
perform various services for them. The services may be of a 
definite and evidently instinctive nature ; or there may be only 
a wish and readiness, as with most of the higher social animals, 
to aid their fellows in certain general ways. But these feelings 
and services are by no means extended to all the individuals of 
the same species, only to those of the same association. Secondly, 
as soon as the mental faculties had become highly developed, 
images of all past actions and motives would be incessantly 
passing through the brain of each individual ; and that feeling 
of dissatisfaction, or even misery, which invariably results, as we 
shall hereafter see, from any unsatisfied instinct, would arise, 
as often as it was perceived that the enduring and always 
present social instinct had yielded to some other instinct, at the 
time stronger, but neither enduring in its nature, nor leaving 

^ Six- B. Brodie, aftei observing all this, he also remarks, " if, as is 

that man is a social animal (' Psy- " my own belief, the moral feelings 

chological Enquiries,' 1854, p. 192), " are not innate, but acquired, they 

asks the pregnant question, " ought " are not for that reason less natu- 

" not this to settle the disputed " ral." It is with hesitation that I 

" question as to the existence of a venture to differ at all from so 

" moral sense ?" Similar ideas have profound a thinker, but it can 

probably occurred to many persons, hardly be disputed that the social 

as they did long ago to Marcus feelings are instinctive or innate in 

Aurelius. Mr. J. S. Mill speaks, in the lower animals ; and why should 

his celebrated work, * Utilitarian- they not be so in man ? Mr. Bain 

ism,' (1864, pp. 45, 46), of the social (see, for instance, 'The Emotions and 

feelino-s as a "powerful natural the Will,' 1865, p. 481) and others 

" sentiment," and as " the natural believe that the moral sense is ac- 

" basis of sentiment for utilitarian quired by each individual during 

" morality." Again he says, " Like his lifetime. On the general theory 

" the other acquired capacities above of evolution this is at least ex- 

" referred to, the moral faculty, if tremely improbable. The ignoring 

'• not a part of our nature, is of all transmitted mental qualities 

'• a natural out-growth from it ; will, as it seems to me, be hereafter 

" capable, like them, in a certain judged as a most serious blemish iu 

" small flegree of springing up spon- the works of Mr. Mill. 
" taneously." But in opposition to 

CiiAi'. IV. Moral Sense. 99 

behind it a very vivid impression. It is clear that many in- 
stinctive desires, sucli as that of hunger, are in their nature of 
short duration; and after being satisfied, are not readily or 
vividly recalled. ThirdJy, 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 act for the 
public good, would naturally become in a paramount degree 
the guide to action. But it should be borne in mind that how- 
ever great weight we may attribute to public oi)inion, our regard 
for the approbation and disapprobation of our fellows depends 
on sympathy, which, as we shall see, forms an essential part of 
the social instinct, and is indeed its foundation-stone, Lastly, 
habit in the individual would ultimately play a very important 
part in guiding the conduct of each member ; for the social in- 
stinct, together with sympathy, is, like any other instinct, greatly 
strengthened by habit, and so consequently would be obedience 
to the wishes and judgment of the community. These several 
subordinate propositions must now be discussed, and some of 
them at considerable length. 

It may be well first to premise that I do not wish to maintain 
that any strictly social animal, if its intellectual faculties were 
to become as active and as highly developed as in man, would 
acquire exactly the same moral sense as ours. In the same 
manner as various animals have some sense of beauty, though 
they admire widely different objects, so they might have a sense 
of right and wrong, though led by it to follow widely different 
lines of conduct. If, for instance, to take an extreme case, men 
were reared under precisely the same conditions as hive-bees, 
there can hardly be a doubt that our unmarried females would, 
like the worker-bees, think it a sacred duty to kill their brothers, 
and mothers would strive to kill their fertile daughters ; and no 
one would think of interfering.*^ Nevertheless, the bee, or any 

^ Mr. H. Sidgwick i-emarks, in in Morals,' 'Theological Review,' 

an able discussion on this subject April, 1872, p. 188-191) on the 

(the 'Academy,' June 15th, 1872, same illustration, says, the j)rin- 

(p. 231), "a superior bee, we may ciplcs of social duty would be thus 

" feel sure, would aspire to a milder reversed ; and by this, I presume, 

" solution of the population ques- she means that the fulfilment of a 

" tion." Judging, however, from social duty would tend to tlie injury 

the habits of many or most savages, ot" individuals ; but she overlooks 

man solves the problem by famale the fact, which she would doubtless 

infanticide, polyandry and promis- admit, that tlie instincts of the bee 

cuous intercourse ; therefore it may have been acquired for the good of 

well be doubted whether it would the community. She goes so far as 

be by a milder method. Jliss to say that if the theory of ethics 

Cobbe, in commenting ('Darwinism advocated in this chapter were ever 

100 The Descent of Ma]i. Part I. 

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 enduring instincts, and others less 
strong or enduring ; so that there would often be a struggle as to 
which impulse should be followed; and satisfaction, dissatis- 
faction, or even misery would be felt, as past impressions were 
compared during their incessant passage through the mind. In 
this case an inward monitor would tell the animal that it would 
have been better to have followed the one impulse rather than 
the other. The one course ought to have been followed, and the 
other ought not ; the one would have been right and the other 
wrong ; but to these terms I shall recur. 

Sociahility. — Animals of many kinds are social ; we find even 
distinct species living together ; for example, some American 
monkeys ; and united flocks of rooks, jackdaws, and starlings. 
Man shews the same feeling in his strong love for the dog, which 
the dog returns with interest. Every one must have noticed how 
miserable horses, dogs, sheep, &c., are when separated from 
their companions, and what strong mutual affection the two 
former kinds, at least, shew on theii* 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 ajDproach animals in a herd or 
troop. Wild horses and cattle do not, I believe, make any 
danger-signal; but the attitude of any one of them who first 
discovers an enemy, warns the others. Eabbits 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 mammals, post sentinels, which in the 
case of seals are said^ generally to be the females. The leader 

generally accepted, " I cannot but earth is not held by many persons 

" believe that in the hour of their on so weak a tenure. 

" triumph would be sounded the " ' Die Darwin'sche Theorie,' s, 

*' knell of the virtue of mankind '." 101, 

It is to be hoped that the belief in * Mr. R. Brown in ' Proc. Zoolog. 

the permanence of virtue on this %<c.' 1868, p. 409. 

Chap. IV. Moral Sense. lOi 

of a troop of monkeys acts as the sentinel, and utters cries 
expressive both of danger and of safety.'' Social animals perform 
jnany 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 Brelim sta,tcs that after a troop 
of the Cercopithecus griseo-vlridls has rushed through a thorny 
brake, each monkey stretches itself on a branch, and another 
monkey sitting by, "conscientiously" examines its fur, and 
extracts every thorn or burr. 

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 Hamadrj^as baboons turn over stones to find 
insects, &c. ; and when they come to a large one, as many as can 
stand round, turn it over together and share the booty. Social 
animals mutually defend each other. Bull bisons in N. America, 
when there is danger, drive the cows and calves into the middle 
of the herd, whilst they defend the outside. I shall also in a 
future chapter give an account of two young wild bulls at 
Chillingham attacking an old one in concert, and of two stallions 
together trying to drive away a third stallion from a troop of 
mares. In Abyssinia, Brehm encountered a great troop of 
baboons, who were crossing a valley : some had already ascended 
the opposite mountain, and some were still in the valley : the 
latter were attacked by the dogs, but the old males immediately 
hurried down from the rocks, and with mouths widely opened, 
roared so fearfully, that the dogs quickly drew back. They 
were again encouraged to the attack ; but by this time all the 
baboons had reascendcd the heights, excepting a young one, 
about six months old, who, loudly calling for aid, climbed on a 
block of rock, and was surrounded. Now one of the largest 
males, a true hero, came down again from the mountain, slowly 
went to the young one, coaxed him, and triumi:)hantly 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 Ccrcopithecus, which, 
by clinging to a branch, was not at once carried off; it cried 
loudly for assistance, upon which the other members of the troop, 
with much uproar, rushed to the rescue, surrounded the eagle, 

9 Brehm, 'Thierlebcn,' B. i. 18G4, the ovi lence of Alvarez, whose ob- 
s. 52, 79. For the cnse of the servatious Brehm thinks quite trust- 
monkeys extracting thorns from worthy. For the cases of the okl 
each other, sec s. 54-. With respect male baboons attacking the dogs, 
to the Hamadryas turning over see s. 79 ; and with respect to the 
stones, the fact is given (s. 76) on eagle, s. 5(3. 

102 The Descent of Man. Part I. 

and pnlled out so many feathers, tliat he no longer thought 
of his prey, but only how to escai)e. This eagle, as Brehm 
remarks, assiu'edly would never again attack a single monkey of 
a troop. ^'^ 

It is eei-tain that associated animals have a feeling of love for 
each other, which is not felt by non-social adult animals. How 
far in most cases they actually sympathise in the pains and 
pleasures of others, is more doubtful, especially with respect to 
])Ieasures. Mr. Buxton, however, who had excellent means of 
observation," states that his macaws, which lived free in Norfolk, 
took " an extravagant interest " in a pair with a nest ; and when- 
ever the female left it, she was surrounded by a troop '" scream- 
" ing horrible acclamations in her honour." It is often diflBcult 
to judge whether animals have any feeling for the sufferings of 
others of their kind. Who can say what cows feel, when they 
surround and stare intently on a dying or dead companion ; ap- 
parently, however, as Houzeau remarks, they feel no pity. That 
animals sometimes are far from feeling any sympathy is too 
certain; for they will expel a wounded animal from the herd, or 
gore or worry it to death. This is almost the blackest fact in 
natural liistory, unless, indeed, the explanation which has been 
suggested is true, that their instinct or reason leads them to 
expel an injured companion, lest beasts of prey, including man, 
should be tempted to follow the troop. In this case their con- 
duct is not much worse than that of the North American Indians, 
who leave their feeble comrades to perish on the plains ; or the 
Fijians, who, when their parents get old, or fall ill, bury them 

Many animals, however, certainly sympathise with each other's 
distress or danger. This is the case even with birds. Capt. 
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 his companions. Mr. Blyth, as he informs 

'' Ml-. Belt gives the case of a " ' Annals and Mag. of Nat. Hist.,' 

spider-monkey (Ateles) in Nicara- Kovember, 1868, p. 382. 

gua, which was heard screaming for ^- Sir J. Lubbock, ' Prehistoric 

nearly two hours in the forest, and Times,' 2nd edit. p. 446. 

was found with an eagle perched ^^ As quoted by Mr. L. H. Morgan, 

close by it. The bird apparently ' The American Beaver,' 1868, p. 

feared to attack as long as it re- 272. Capt. Stansbury also gives an 

mained f\\ce to face; and Mr. Belt interesting account of the manner 

believes, from what he has seen of in which a very young pelican, 

the habits of these monkeys, that carried away by a strong stream, 

they protect themselves from eagles was guided and encouraged in its 

by "keeping two or three together, attempts to reach the shore by half 

'The Naturalist in Nicaragua,' 1874, a dozen old birds 
p. 118. 

Chap. IV. Moral Sense. 103 

me, saw Indian crows feeding two or three of their companions 
which were blind ; and I have heard of an analogous case with 
the domestic cock. We may, if we choose, call these actions 
instinctive ; but such cases are much too rare for the develop- 
ment of any special instinct.^* 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,»tlie 
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 give only one other instance of sympathetic 
and heroic conduct, in the case of a little American monkey. 
Several years ago a keeper at the Zoological Gardens shewed me 
some deep and scarcely healed wounds on the nape of his own neck, 
inflicted on him, whilst kneeling on the floor, by a fierce baboon. 
The little American monkey, who was a warm friend of this 
keeper, lived in the same large compartment, and was dreadfully 
afraid of the great baboon. Nevertheless, as soon as he saw his 
friend in peril, he rushed to the rescue, and by screams and bites 
so distracted the baboon that the man was able to escape, after, 
as the surgeon thought, running great risk of his life. 

Besides love and symi:>athy, animals exhibit other qualities 
connected with the social instincts, which in us would be called 
moral ; and I agree with Agassiz ^^ that dogs possess something 
very hke 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 elei)hant is likewise very faith- 
ful to his driver or keeper, and probably considers him as the 

'* As Mr. Bain states, "effective ^^ ' De I'Esp&ce ct dc la Classe,' 

" aid to a sufferer springs from sym- 18(59, p. 97. 

" pathy proper :" 'Mental and Moral *' ' Die Darwin'sclic Art-Lehre,* 

Science,' 1868, p. 245. 18G9, s. 54. 

*^ 'Thierleben, B. i. s, 85. 

T04 The Descent of Man. Pari I. 

leader of the lierd. Dr. Hooker informs me that an elephant, 
which he was riding in India, became so deeply bogged that he 
remained stnck fast until the next day, when he was extricated 
by men with ropes. Under snch circumstances elephants will 
seize with their trunks any object, dead or alive, to place under 
their knees, to prevent their sinking deeper in the mud ; and the 
driver was dreadfully afraid lest the animal should have seized 
Dr. Hooker and crushed him to death. But the driver himself, 
as Dr. Hooker was assured, ran no risk. This forbearance under 
an emergency so dreadful for a heavy animal, is a wonderful 
proof of noble fidelity .^^ 

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 baboons 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. j\Ir. Galton, who has had 
excellent opportunities for observing the half-wild cattle in S. 
Africa, says,-" that they cannot endure even a momentary separa- 
tion 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 assidu- 
ously for those who, by grazing apart, shew a self-reliant dis- 
position, and these they train as fore-oxen. Mr. Galton adds 
that such animals are rare and valuable ; and if many were born 
they would soon be eliminated, as lions are always on the look- 
out for the individuals which wander from the herd. 

"With respect to the impulse which leads certain animals to 
associate together, and to aid one another in many ways, we 
may infer that in most cases they are impelled by the same 
sense of satisfaction or pleasure which they experience in per- 
forming other instinctive actions; or by the same sense of 
dissatisfaction as when other instinctive actions are checked. 
^Ye see this in innumerable instances, and it is illustrated in a 
striking manner by the acquired instincts of our domesticated 
animals ; thus a young shepherd-dog delights in driving and 
running round a flock of sheep, but not in worrying them ; a 
young fox-hound delights in hunting a fox, whilst some other 
kinds of dogs, as I have witnessed, utterly disregard foxes. What 

^^ See also Hooker's ' Himalayan 20 See his extremely interesting 

Journals,' vol. ii., 1854, p. 333. paper on ' Gregariousness in Cattle, 

** Brehm, ' Thierleben,' B. i. s. and in Man,' ' Macmiilan's Mag.' Feb. 

7G. 1871, p. 353. 

Chap. IV. Moral Sense. 105 

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; perliajjs 
they enjoy starting on their long flight ; but it is hard to believe 
that the poor pinioned goose, described by Audubon, which 
started on foot at the proper time for its journey of probably 
more than a thousand miles, could have felt any joy in doing so. 
Some instincts are determined solely by painful feelings, as by 
fear, which leads to self-preservation, and is in some cases directed 
towards special enemies. No one, I presume, can analyse the 
sensations of pleasure or pain. In many instances, however, it 
is probable that instincts are persistently followed from the 
mere force of inheritance, without the stimulus of either 
l">leasure or pain. A young pointer, when it tirst scents game, 
apparently cannot help pointing. A squirrel in a cage who pais 
the nuts which it cannot eat, as if to bury them in the ground, 
can hardly be thought to act thus, either from pleasure or pain. 
Hence the common assumption that men must be impelled to 
every action by experiencing some pleasure or pain may be erro- 
neous. Although a habit may be blindly and implicitly 
followed, independently of any j^lcasure or pain felt at the 
moment, yet if it be forcibly and abruptly checked, a vague 
sense of dissatisfaction is generally experienced. 

It has often been assumed that animals were in the first place 
rendered social, and that they feel as a consequence uncomfort- 
able when separated from each other, and comfortable whilst 
together ; but it is a more probable view that these sensations 
were first developed, 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 j^lcasure 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 attri- 
buted in part to habit, but chiefly to natural selection. With 
tliose animals which were benefited by living in close association, 
the individuals which took the greatest pleasure in society 
would best escape various dangers; whilst those that cared 
least for their comrades, and lived solitary, would perish in 
greater numbers. With respect to the origin of the parental 
and fihal 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 

io6 The Descent of Man. Part T. 

been with the unusual aiid opposite feeling of hatred between 
the nearest relations, as with the worker-bees which kill their 
brother-drones, and with the queen-bees which kill their 
daughter-queens; the desire to destroy their nearest relations 
having been in this case of service to the community. Parental 
affection, or some feeling which replaces it, has been developed 
in certain animals extremely low in the scale, for example, in 
star-fishes and spiders. It is also occasionally present in a few 
members alone in a whole group of animals, as in the genus 
Forficula, or earwigs. 

The all-important emotion of sympathy is distinct from that 
of love. A mother may passionately love her sleeping and 
passive infant, but she can hardly at such times be said to feel • 
sympathy for it. The love of a man for his dog is distinct from 
sympathy, and so is that of a dog for his master. Adam Smith 
formerly argued, as has Mr. Bain recently, that the basis of 
sympathy Hes in our strong retentiveness of former states of 
pain or pleasure. Hence, "the sight of another person en- 
" during hunger, cold, fatigue, revives in us some recollection of 
" these states, which are painful even in idea." We are thus 
impelled to relieve the sufferings of another, in order that our 
own painful feelings may be at the same time relieved. In Hke 
manner we are led to participate in the pleasures of others.^' 
But I cannot see how this view explains the fact that sympathy 
is excited, in an immeasurably stronger degree, by a beloved, 
than by an indifferent person. The mere sight of suffering, 
independently of love, would suffice to call up in us vivid 
recollections and associations. The explanation may lie in the 
fact that, with all animals, sympathy is dhected solely towards 
the members of the same community, and therefore towards 
known, and more or less beloved members, but not to all the 
individuals of the same species. This fact is not more sur- 
prising than that the fears of many animals should be directed 
against special enemies. Species which are not social, such as 
lions and tigers, no doubt feel sympathy for the suffering of 
tbeir own young, but not for that of any other animal. With 

21 See the first and striking " or others in his stead, may make 

chapter in Adam Smith's ' Theory " up, by sympathy and good offices 

of Moral Sentiments.' Also Mr. " returned, for all the sacrifice." 

Bain's ' Mental and Moral Science,' But if, as appears to be the case, 

1868, p. 244, and 275-282. Mr. sympathy is strictly an instinct, 

Bain states, that "sympathy is, in- its exercise would give direct plea- 

" directly, a source of pleasure to sure, in the same manner as the 

" the sympathiser ;" and he accounts exercise, as before remarked, of al- 

f(ir this through reciprocity. He most every other instinct, 
remarks that " the person benefited, 

CtiAP. IV. Moral Sense. 107 

mankind, sclfislincss, 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 commu- 
nities, which included the greatest number of the most sympa- 
thetic members, would flourish best, and rear the greatest 
number of offspring. 

It is, however, impossible to decide in many cases whether 
certain social instincts have 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, there- 
fore, 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 sym^Dathy ; 
but courage, and in most cases strength, must have been 
previously acquired, probably through natural selection. 

Of the various instincts and habits, some are mnch stronger 
than others ; that is, some either give more pleasure in their 
performance, and more distress in their prevention, than others ; 
or, ^hich is probably quite as important, they are, through 
inheritance, more persistently followed, without exciting any 
special feeling of pleasure or pain. We are ourselves conscious 
that some habits are much more difficult to cure or change than 
others. Hence a struggle may often be observed in animals 
between different instincts, or between an instinct and some 
habitual disposition; as when a dog rushes after a hare, is 
rebuked, pauses, hesitates, pursues again, or returns ashamed to 
his master ; or as between the love of a female dog for her young 
l-)uppies and for her master,— for she may be seen to slink away 
to them, as if half ashamed of not accompanying her master. 
But the most carious instance known to me of one instinct 
getting the better of another, is the migratory instinct conquer- 
ing the maternal instinct. The former is wonderfully strong; a 
confined bird will at the proper season beat her breast against 
the wires of her cage, until it is bare and bloody. It causes 
young salmon to leap out of the fresh water, in which they could 

io8 The: Descent of Man. Part T. 

continue to exist, and thus unintentionally to commit suicide. 
Every one knows how strong the maternal instinct is, leading 
even timid birds to face great danger, though with hesitation, 
and in opposition to the instinct of self-preservation. Neverthe- 
less, the migratory instinct is so powerful, that late in the autumn 
swallows, house-martins, and swifts frequently desert their 
tender young, leaving them to perish miserably in their nests.^^ 

We can perceive that an instinctive impulse, if it be in any 
way more beneficial to a species than some other or ojDposed 
instinct, would be rendered the more potent of the two through 
natural selection ; for the individuals which had it most strongly 
developed would survive in larger numbers. Whether this is the 
case with the migratory in comparison with the maternal instinct, 
may be doubted. The great persistence, or steady action of the 
former at certain seasons of the year during the whole day, may 
give it for a time paramount force. 

Man a social animal. — Every one will admit that man is a 
social being. We see this in his dislike of solitude, and. in his 
wish for society beyond that of his own family. Solitary con- 
finement is one of the severest punishments which can be 
inflicted. Some authors suppose that man primevally lived in 
single families ; but at the present day, though single families, 
or only two or three together, roam the solitudes of some savage 
lands, they always, as far as I can discover, hold friendly 
relations with other families inhabiting the same district. Such 
families occasionally meet in council, and unite for their common 
defence. It is no argument against savage man being a social 
animal, that the tribes inhabiting adjacent districts are almost 
always at war with each other ; for the social instincts never 
extend to all the individuals of the same species. Judging from 
the analogy of the majority of the Quadrumana, it is probable 
that the early ape-like progenitors of man were likewise social ; 
but thLs is not of much importance for us. Although man, as 

^* This fact, the Rev. L. Jenyns hatched. Many birds, not yet old 

states (see his edition of ' White's enough for a prolonged flight, are 

Nat. Hist, of Selborne,' 1853, p. likewise deserted and left behind. 

204) was first recorded by the illus- See Blackwall, 'Researches in Zoo- 

trious Jenner, in 'Phil. Transact,' logy,' 1834, pp. 108, 118. For some 

1824, and has since been confirmed additional evidence, although this 

by several observers, especially by is not wanted, see Leroy, ' Lettres 

Mr. Blackwall. This latter careful Phil.' 1802, p. 217. For Swifts, 

observer examined, late in the Gould's ' Introduction to the Birds 

autumn, during two years, thirty- of Great Britain,' 1823, p. o. Simi- 

six nests ; he found that twelve lar cases have been observed in 

contained young dead birds, five Canada by Mr. Adams ; ' Pop. 

contained eggs on the point of being Science Review,' July 1873, p. 

hatched, and three, eggs not nearly 283. 

CiiAP. IV. Moral Sense. 109 

ho now exists, has few special instincts, having lost any which 
his early progenitors may have possessed, tliis is no reason wliy 
he should not have retained from an extremely remote period 
some degree of instinctive love and sympathy for his fellows. 
We are indeed all conscious that we do possess such sympathetic 
feelings ; -^ but our consciousness does not tell ns whether they 
are instinctive, having originated long ago in the same manner 
as with the lower animals, or whether tliey 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 comrades, and obedient to the leader of his tribe ; 
for these qualities are connnon to most social animals. lie would 
consequently possess some capacity for self-command. lie 
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 arc 
likewise in part impelled by mutual love and sympathy, assisted 
apparently by some amount of reason. Although man, as just 
remarked, has no special instincts to tell him how to aid his 
fellow-men, he still has the impulse, and with his improved 
intellectual faculties would naturally be much guided in this 
respect by reason and experience. Instinctive sympathy would 
also cause him to value highly the approbation of his fello^^s ; 
for, as Mr. Bain has clearly shewn,^^ the love of praise and 
the strong feeling of glory, and the still stronger horror of scorn 
and infamy, " are due to the workings of sympathy." Conse- 
quently man would be influenced in the highest degree by the 
wishes, approbation, and blame of his fellow-men, as expressed 
by their gestures and language. Thus the social instincts, 
which must have been acquired by man in a very rude state, 
and probably even by his early ape-like progenitors, still give 
the impulse to some of his best actions : but his actions are in a 
higher degree determined by the expressed wishes and judgment 

2' Hume remarks ('An Enquiiy *' of the former . . . communicates 

Concerning the Principles of Morals,' "a secret joy; the appearance of 

edit, of 1751, p. lo2), "There seems "the latter . . . throws a melau- 

" a necessity for confessing that the " choly damp ov6r the imagiua- 

" happiness and misery of others " tion." 

"are not spectacles altogether in- '^■' 'Mental ami Moral Science,' 

" different to us. but that the view ISGS, p. 2.04 

no TJie Descent of Man. Tart 1. 

of his fellow-men, and unfortunately very often by his own strong 
selfish desires. But as love, sympathy and self-command become 
strengthened by habit, and as the power of reasoning becomes 
clearer, so that man can value justly the judgments of his 
fellows, he will feel himself impelled, apart from any transitory 
pleasure or pain, to certain lines of conduct. He might then 
declare — not that any barbarian or uncultivated man could 
thus think — I am the supreme judge of my own conduct, and in 
the words of Kant, I will not in my own person violate the 
dignity of humanity. 

The more enduring Socid Instincts conquer the less 2yersisfent 
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 desii*e 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 instinc- 
tive impulses have different degi-ees 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 greatest danger for her own infant, 
but not for a mere fellow-creature. Nevertheless many a 
civilized man, or even boy, who never before risked his life for 
andther, but full of courage and sympathy, has diregarded 
the instinct of self-preservation, and plunged at once into a 
torrent to save a drowning man, though a stranger. In this case 
man is impelled by the same instinctive motive, which made the 
heroic little American monkey, formerly described, save his 
keeper, by attacking the great and dreaded baboon. Such 
actions as the above appear to be the simple result of the gi-eater 
strength of the social or maternal instincts than that of any 
other instinct or motive; for they are perfonned too instan- 
taneously for reflection, or for pleasure or pain to be felt at the 
time ; though, if prevented by any cause, distress or even misery 
might be felt. In a timid man, on the other hand, the instinct 
of self-preservation might be so strong, that he would be unable 
to force himself to run any such risk, perhaps not even for his 
own child. 

I am aware that some persons maintain that actions performed 
impulsively, as in the above cases, do not come under the 
domijiion of the moral sense, and cannot be called moral. They 

Chap. iV. Mora/ Sense. 1 1 1 

confine this term to actions done deliberately, after a victory 
over opposing desires, or when prompted l)y 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 benevolence towards mankind, 
and not guided by any religious motive, who have deliberately 
sacrificed their lives as i)risoners,^'' rather than betray their 
comrades; and surely their conduct ought to be considered as 
moral. As far as deliberation, 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 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, w^e 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, wdien 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 performed deliberately, after a struggle with oj^posing 

"^^ I refer here to the distinction " material and formal morality is 

between what has been called ma- " as irrelevant as other siuh dis- 

terial and formal morality. I am " tinctions." 

glad to find that Prof. Huxley ('Cri- ^g j have given one such case, 

tiques and Addresses,' 1873, p. 287) namely of three Patagonian Indians 

takes the same view on this subject who jtreferred being shot, one after 

as I do. Mr. Leslie Stc])hen re- the other, to betraying the ]»lans of 

marks (' Essavs on Freethinking and their companions in war (' Journal 

Plain Speaking,' 1873, p. 8;'.)/" the of Researches,' 1845, p. 103). 
" metaphysical distinction betwceu 

112 The Descent of Man. Part I. 

motives, or impulsively through instinct, or from the effects of 
slowly-gained habit. 

But to return to our more immediate subject. Although 
some uistincts are more powerful than others, and thus lead to cor- 
responding actions, yet it is untenable, that in man the social 
instincts (including the love of praise and fear of blame) possess 
greater strength, or have, through long habit, acquired greater 
strength than the instincts of self-preservation, hunger, lust, 
vengeance, &c. Why then does man regret, even though trying 
to banish such regret, that he has followed the one natural 
impulse rather than the other ; and why does he further feel 
that he ought to regret his conduct ? Man in this respect differs 
profoundly from the lower animals. Nevertheless we can, I think, 
see with some degree of clearness the reason of this difference. 

Man, from the activity of his mental faculties, cannot avoid 
reflection : past impressions and images are incessantly and 
clearly passing through his mind. Now with those animals 
which live permanently in a body, the social instincts are ever 
present and persistent. Such animals are always ready to utter 
the danger-signal, to defend the community, and to give aid to 
their fellows in accordance w^ith their habits ; they feel at all 
times, without the stimulus of any special passion or desire, 
some degree of love and sympathy for them ; they are unhappy 
if long separated from them, and always happy to be again m 
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 aijprobation or 
disapprobation; and this all follows from sympathy, a funda- 
mental element of the social instincts. A man who possessed 
no trace of such instincts would be an unnatural monster. On 
the other hand, the desire to satisfy hunger, or any passion such 
as vengeance, is in its nature temporary, and can for a time be 
fully satisfied. Nor is it easy, jDcrhaps 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 jDsrhaps as persistent a desire as any that can be 
named; but even in this case the satisfaction of actual pos- 
session is generally a weaker feeling than the desire : many a 
thief, if not a habitual one, after success has wondered why he 
stole some article.^ 

^^ Enmity or hatred seems also perhaps more so than auy other 
to be a highly persistent feeling, that can be named. Envy is de- 

Chap. IV. Moral Sense. 1 1 3 

A man cannot jircYcnt past impressions often repassing tlirongli 
liis mind ; lie will thns be driven to make a comparison between 
tbo imjiressions of past Imnger, 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 praise v/Orthy or blameable. This knowledge 
cannot be banished from his mind, and from instinctive sympathy 
is esteemed of great moment. He will then feel as if he had 
been baulked in following a present instinct or habit, and this 
with all animals causes dissatisfaction, or even misery. 

The above case of the swallow affords an illustration, though 
of a reversed nature, of a temporary though for the time strongly 
persistent instinct con(iuering another instinct, which is usually 
dominant over all others. At the proper season these birds 
seem all day long to be impressed with the desire to migrate ; 
their habits change ; they become restless, are noisy, and con- 
gregate in flocks. Whilst the mother-bird is feeding, or brooding 
over her nestlings, the maternal instinct is probably stronger 
than the migratory ; but the instinct wiiich is the more persis- 
tent gains the victory, and at last, at a moment when her young 
ones are not in sight, slic 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 through her 
mind, of her young ones perishing in the bleak north from cold 
and hunger. 

fined as hatred of another for some had done him an injiirv and liad 
excellence or success; and Bacon become his enemy, iv'or is it pro- 
insists (Essay ix.), " Of all otlier bable that the primitive conscience 
" affections envy is the most im- would reproach a man lor injurin;-- 
" port une and continual." Dogs ai-e his enemy: ratlier it would re- 
very apt to hate both strange men proach him, if he had not revenged 
and strange dogs, esjiecially if they himself. To do good in return lor 
live near at hand, but do not beU)ng evil, to love your enemy, is a height 
to the same family, tribe, or clan; of morality to which it mav^be 
this feeling would thus seem to be doubted whether the social instincts 
innate, and is certainly a most per- would, by themselves, have ever led 
sistent one. It seems to be the us. It is necessary that these in- 
complement and converse of the stincts, together with sympathy, 
true social instinct. From what should have been highly cultivated 
we hear of savages, it would appear and extended l)y the aid of reason, 
that something of the same kind instruction, and the love or fear of 
holds good with them. If this be God, before any such golden rule 
so, it would be a small step in would ever be thought of and 
any one to transfer such feelings to obeyed. 
any member of the same tribe if he 

1 14 The Descent of Man. Part I. 

A-t the moment of action, man will no doubt be apt to follow 
the stronger impulse; and though this may occasionally 
prompt him to the noblest deeds, it will more commonly lead 
him to gratify his own desires at the expense of other men. 
But after their gratification, when past and weaker impressions 
are judged by the ever-enduring social instinct, and by his deep 
regard for the good opinion of his fellows, retribution will surely 
come. He will then feel remorse, repentance, regret, or shame; 
this latter feeling, however, relates almost exclusively to the 
judgment of others. He will consequently resolve more or less 
firmly to act differently for the future ; and this is conscience ; for 
conscience looks backwards, and seiwes 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 
feeling of sympathy ; and on his own capacity for reasoning out 
the remote consequences of his acts. Another element is most 
important, although not necessary, the reverence or fear of the 
Gods, or Spirits believed in by each man : and this applies 
especially in cases of remorse. Several critics have objected 
that though some shght regret or repentance may be explained 
by the view advocated in this chapter, it is impossible thns to 
account for the soul-shaking feeling of remorse. But I can see 
little force in this objection. My critics do not define what 
they mean by remorse, and I can find no definition implying 
more than an overwhelming sense of repentance. Eemorse 
seems to bear the same relation to rej^entance, as rage does to 
anger, or agony to pain. It is far from strange that an instinct 
so strong and so generally admired, as maternal love, should, if 
disobeyed, lead to the deepest misery, as soon as the impression 
of the past cause of disobedience is weakened. Even when an 
action is opposed to no special instinct, merely to know that our 
friends and equals despise ns for it is enough to cause great 
misery. Who can doubt that the refusal to fight a duel tlu-ough 
fear has caused many men an agony of shame ? Many a Hindoo, 
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 remorse. 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 " he was 

23 ' Insanity in Relation to Law;' Ontario, United States, 1871, p. 14. 

CuAP. IV. Moral Soisc. 1 1 5 

" going to a distant tribe to spear a woman, to satisfy liis sense 
'' of duty to liis wife. I told liim that if lie 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 cat, that his wife's spirit was haunting 
" him, because he had not taken a life for hers. I was in- 
" exorable, and assured him that nothing should save him if he 
" did." Nevertheless the man disappeared for more than a year, 
and then returned in high condition ; and his other wife told 
Dr. Landor that her husband had taken the life of a woman 
belonging to a distant tribe ; but it was impossible to obtain 
legal evidence of the act. The breach of a rule held sacred by 
the tribe, will thus, as it seems, give rise to the deepest feelings, 
— and this quite apart from the social instincts, excepting in so 
far as the rule is grounded on the judgment of the community. 
How so many strange superstitions have arisen throughout the 
world we know not ; nor can wc tell how some real and great 
crimes, such as incest, have come to be held in an abhorrence 
(which is not however quite universal) by the lowest savages. It 
is even doubtful whether in some tribes incest would be looked on 
with greater horror, than would the marriage of a man with a 
woman bearing the same name, though not a relation. " To 
" violate this law is a crime which the Australians hold in the 
" greatest abhorrence, in this agreeing exactly with certain 
" tribes of North America. When the question is put in either 
" district, is it worse to kill a girl of a foreign tribe, or to marry 
" a girl of one's own, an answer just opposite to oui's would be 
given without hesitation." ^^ We may, therefore, reject the 
belief, lately insisted on by some writers, that the abhorrence of 
incest is due to our possessing a special God -implanted con- 
science. On the whole it is intelligible, that a man urged by 
so powerful a sentiment as remorse, though arising as above 
explained, should be led to act in a manner, which he has been 
taught to believe serves as an expiation, such as delivering 
himself up to justice. 

Man prompted by his conscience, will through long habit 
acquire such perfect self-command, that his desires and passions 
will at last yield instantly and without a struggle to his social 
sympathies and instincts, including his feeling for the judgment of 
his fellows. The still hungry, or the still revengeful man will not 
think of stealing food, or of wreaking his vengeance. It is possible, 
or as we shall hereafter see, even probable, that the habit of self- 
command may, like other habits, be inherited. Thus at last man 

'* E. B. Tylor iu 'Contemporary Review,' April, 1873, p. 707. 

1 1 6 The Descent of Man. Part I 

comes to feel, through acquired and perhaps inherited habit, that 
it is best for him to obey his more persistent impulses. The 
imperious word oz((/A^ seems merely to imply the consciousness of 
the existence of a rule of conduct, however it may have 
originated. Formerly it must have been often vehemently 
urged that an insulted gentleman ought to fight a duel. We 
even say that a pointer ouglit to point, and a retriever to 
retrieve game. If they fail to do so, they fail in their duty 
and act wrongly. 

If any desire or instinct leading to an action opposed to the 
good of others still appears, when recalled to mind, as strong 
as, or stronger than, the social instinct, a man will feel no keen 
regret at having followed it ; but he will be conscious that if his 
conduct were known to his fellows, it would meet with their 
disapprobation ; and few are so destitute of sympathy as not to 
feel discomfort when this is realised. If he has no such 
sympathy, and if his desires leading to bad actions are at the 
time strong, and when recalled are not over-mastered by the 
persistent social instincts, and the judgment of others, then he 
is essentially a bad man ; ^" 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-rejDroach, or at least of anxiety, it is almost neces- 
sary for him to avoid the disapprobation, whether reasonable or 
not, of his fellow-men. Nor must he break through the fixed 
habits of his life, especially if these are supported by reason; 
for if he does, he will assuredly feel dissatisfaction. He must 
likewise avoid the reprobation of the one God or gods in whom, 
according to his knowledge or superstition, he may believe ; but 
in this case the additional fear of divine punishment often 

The strictly Social Virtues at first alone regarded. — The above 
view of the origin and nature of the moral sense, which tells us 
what we ought to do, and of the conscience which reproves us if 
we disobey it, accords well with what we see of the early and 
undeveloped condition of this faculty in mankind. The virtues 
which must be practised, at least generally, by rude men, so 

*" Dr. Prosper Despine, in his many curious cases of the worst 
' Psychologic Naturelle,' 1868 (torn. criminals, who apparently have been 
I. p, 243; torn. ii. p. 1G9) gives entirely destitute of conscience. 

CiiAp IV. Moral Sense. 117 

tliat they may associate in a body, arc those which arc still 
recognised as the most important. But they are practised 
almost exclusively in relation to the men of the same tribe ; and 
their opposites are not regarded as crimes in relation to the men 
of other tribes. No tribe could hold together if murder, 
robbery, treachery, &c., were common; consequently such 
crimes within the limits of the same tribe "are branded with 
"everlasting infamy ;"^^ but excite no such sentiment beyond 
these limits. A North-American Indian is well pleased with 
himself, and is honoured by others, when he scalps a man of 
another tribe ; and a Dyak cuts off the head of an unoflfending 
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 infcinticide, 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 honourable 
act ; and it is still practised by some semi-civilised and savage 
nations without reproach, for it does not obviously concern 
others of the tribe. It has been recorded that an Indian Thug 
conscientiously regretted that he had not robbed and strangled 
as many travellers as did his father before him. In a rude state 
of civilisation the robbery of strangers is, indeed, generally 
considered as honourable. 

Slavery, although in some ways beneficial during ancient 
times,^'* is a great crime ; yet it was not so regarded until quite 
recently, even by the most civilized nations. And this was 
especially the case, because the slaves belonged in general to a 
race different from that of their masters. As barbarians do not 
regard the opinion of their women, wives are commonly treated 
like slaves. Most savages are utterly indiifcrcnt to the sufferings 
of strangers, or even delight in witnessicg them. It is well 

3' See an able article in the of European Morals,' vol. i. 18G9, 

* North British Review,' 1867, p. p. 223. With respect to savages, 

395. See also Mr. W. Bagehot/s ^Mr. Winwood Keade informs me 

articles on the Importance of Obe- that the negroes of West Africa 

dience and Coherence to Primitive often commit suicide. It is well 

Man, in the 'Fortnightly Review,' known how common it was amongst 

1867, p. 529, and 1868, p. 457, &c. the miserable aborigines of South 

^2 The fullest account which I America, after the Spanish conquest, 

have met with is by Dr. Gerland, in For New Zealand, see the voyage of 

his 'Ueber dan Aussterben der the " Novara," and for the Aleutian 

Naturvolker,' 1868; but I shall Islands, Miiiler, as quoted by Hou- 

have to recur to the subject of zeau, ' Les Facultes Mentalcs,' &c., 

infanticide in a future chapter. torn. ii. p. 136. 

'^ See the very interesting discus- ^^ Sec Mr. Bagehot, ' Physics and 

sicn on Suicide in Lecky's 'History Politics,' 1872, p. 72. 

1 18 The Descent of Man, Part I. 

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 common, especially during sickness, between the 
members of the same tribe, and is sometimes extended beyond 
these limits. Mungo Park's touching account of the kindness of 
the negro women of the interior to him is well known. Many 
instances could be given of the noble fidehty of savages towards 
each other, but not to strangers ; common experience justifies 
the maxim of the Spaniard, "Never, never trust an Indian." 
There cannot be fidelity without truth ; and this fundamental 
virtue is not rare between the members of the same tribe : thus 
Mungo Park heard the negi-o women teaching their young 
childi-en to love the truth. This, again, is one of the virtues 
which becomes so deeply rooted in the mind, that it is sometimes 
practised by savages, even at a high cost, towards strangers ; but 
to lie to your enemy has rarely been thought a sin, as the history 
of modern diplomacy too plainly shews. As soon as a tribe has 
a recognised leader, disobedience becomes a crime, and even 
abject submission is looked at as a sacred virtue. 

As during rude times no man can be useful or faithful to his 
tribe without courage, this quality has universally been placed 
in the highest rank; and although in civihsed countries a 
good yet timid man may be far more useful to the community 
than a brave one, we cannot helj) instinctively honouring the 
latter above a coward, however benevolent. Prudence, on the 
other hand, which does not concern the welfare of others, though 
a very useful virtue, has never been highly esteemed. As no 
man can practise 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 tortui-es without a groan, to prove and 
strengthen his fortitude and courage; and we cannot help 
admiring him, or even an Indian Fakir, who, from a foolish 
religious motive, swings suspended by a hook buried in his 

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 
ax^preciated by civilised nations. The greatest intemperance 

^^ See, for instance, Mi'. Hamilton's account of the Kaffirs, ' Anthro- 
pological Review,' 1870, p. xv. 

CiiAi'. IV. Moral Sense. 119 

is no rcproach with savages. Utter licentiousness, and un- 
natural 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 honoured, will tend to spread to tlie 
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 honoured from a very early 
period in the moral history of civilised man. As a consequence 
of this, the senseless practice of celibacy has been ranked from a 
remote period as a virtue.^^ The hatred of indecency, which 
appears to us so natural as to be thought innate, and which is 
so valuable an aid to chastity, is a modern virtue, appertaining 
exclusively, as Sir G. Staunton remarks,^^ to civilised life. This 
is shewn by the ancient religious rites of various nations, by the 
drawings on the walls of Pompeii, and by the practices of many 
savages. » 

We have now seen that actions are regarded by savages, and 
were probably so regarded by primeval man, as good or bad, 
solely as they obviously affect the welfare of the tribe,— not that 
of the si^ecies, nor that of an individual member of the tribe. 
Tliis conclusion agrees well with the belief that the so-called 
moral sense is aboriginally derived from the social instincts, for 
both relate at first exclusively to the community. The chief 
causes of the low morality of savages, as judged by our 
standard, are, firstly, the confinement of sympathy to the same 
tribe. Secondly, powers of reasoning insufficient to recognise 
the bearing of many virtues, especially of the self-regarding 
virtues, on the general welfare of the tribe. Savages, for 
instance, fail to trace the multiplied evils consequent on a 
want of temperance, chastity, &c. And, thirdly, weak power 
of self-command ; for this jDower has not been strengthened 
through long-continued, perhaps inherited, habit, instruction and 

I 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 

^^ Jlr. M'l.ennaa has given ''^ ' Embassy to China,' vol. ii. p. 

(' Primitive Marriage,' 1865, p. 348. 

176) a good collection of facts on ^^ See on this subject copious 

this head. evidence in Chap. vii. ol' Sir J. Lub- 

•*' Lecky, 'History of European bock, ' Origin of Civilisation,' 1870. 
Morals,' vol. i. 1869, p. 109. " For instance Lecky, 'Hist. 

European Morals,' vol. i. p. 12}-. 

1 20 The Descent of Man. Paet T. 

conclusion on savages possessing those virtues which are ser- 
viceable, 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 Bemarhs. — It was assumed formerly by philosophers 
of the derivative*^ school of morals that the foundation of morality 
lay in a form of Selfishness ; but more recently the " Greatest 
" happiness principle " has been brought prominently forward. 
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 have consulted, with a few excep- 
tions,*^ write as if there must be a distinct motive for every 
action, and that this must be associated with some pleasure or 
displeasure. But man seems often to act impulsively, that is 
from instinct or long habit, without any consciousness of pleasure, 
in the same manner as does probably a bee or ant, when it 
blindly follows its instincts. Under circumstances of extreme 
peril, as during a fire, when a man endeavours to save a fellow- 
creature without a moment's hesitation, he can hardly feel 
pleasure ; and still less has he time to reflect on the dissatisfaction 
which he might subsequently experience if he did not make the 
attempt. Should he afterwards reflect over his own conduct, he 
would feel that there lies within him an impulsive power widely 
different from a search after pleasure or happiness; and this 
seems to be the deeply planted social instinct. 

In the case of the lower animals it seems much more appro- 
priate to speak of their social instincts, as having been developed 

•*^ This term is used in an able " noss extra -regarding impulse, di- 

article in the 'Westminster Review,' " recied towards something that is 

Oct. 1869, p. 498. For the " Greatest "not pleasure; that in many cases 

" happiness principle," see J. S. Mill, " the impulse is so far incompatible 

' Utilitarianism,' p. 17. " with the self-regarding that the 

^2 Mill recognises (' Sj'stem of " two do not easily co-exist in the 

Logic,' vol. ii., p. 422) in the clearest " same moment of consciousness." 

manner, that actions mny be per- A dim feeling that our impulses do 

formed through habit without the not by any means always arise from 

anticipation of pleasure. Mr. H. any contemporaneous or anticipated 

Sidgwick also, in his Essay on pleasure, has, I cannot but think. 

Pleasure and Desire ('The Con- been one chief cause of the accept- 

temporary Review,' April 1872, p. ance of the intuitive theory of 

671), remarks: "To sum up, in morality, and of the rejection of the 

" contravention of the doctrine that utilitarian or " Greatest happiness '' 

" our conscious active impulses are theory. With respect to the latter 

" always directed towards the pro- theory, the standard and the motive 

" duction of agreeable sensations in of conduct have no doubt often been 

" ourselves, I would maintain that confused, but they are really in 

" we find everywhere in conscious- some degree blended. 

Chap. IV. Mo7'al Sense. 1 2 1 

for the general good rather than for the general happiness of the 
species. The term, general good, may be 'defined as the rearing 
of the greatest number of individuals in full vigour and health, 
with all their faculties perfect, under the conditions to which 
they are subjected. As the social instincts both of man and the 
lower animals have no doubt been developed by nearly the same 
steps, it would be advisable, if found practicable, to use the 
same definition in both cases, and to take as the standard of 
morality, the general good or welfare of tlie community, rather 
than the general happiness ; but this definition would perhaps 
require some limitation on account of political ethics. 

When a man risks his life to save that of a fellow-creature, it 
seems also more correct to say that he acts for the general good, 
rather than for the general happiness of mankind. No doubt 
the welfare and the happiness of the individual usually coincide ; 
and a contented, happy tribe will flourish better than one that 
is discontented and unhappy. We have seen that even at an 
early period in the history of man, the expressed wishes of 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 im- 
portant secondary guide and object ; the social instinct, however, 
together with sympathy (which leads to our regarding the 
approbation and disapprobation of others), having served as the 
primary impulse and guide. Thus the reproach is removed of 
laying the foundation of the noblest part of our nature in the 
base principle of selfishness; unless, indeed, the satisfaction 
which every animal feels, when it follows its proper instincts, 
and the dissatisfaction felt when prevented, be called selfish. 

The wishes and opinions of the members of the same community, 
expressed at first orally, but later by writing also, either form 
the sole guides of our conduct, or greatly reinforce the social 
instincts ; such opinions, however, have sometimes a tendency 
directly opposed to these instincts. This latter fact is well 
exemplified by the Law of Honour, that is, the law of the opinion 
of our equals, and not of all our countrymen. The breach of 
this law, even when the breach is known to be strictly accordant 
with true morality, has caused many a man more agony than a 
real crime. We recognise the same influence in the burning 
sense of shame which most of us have felt, even after the interval 
of years, when calling to mind some accidental breach of a 
trifling, though fixed, rule of etiquette. The judgment of the 
community will generally be guided by some rude experience of 
what is best in the long run for all the members ; but this judg- 
ment will not rarely err from ignorance and weak i^owers of 

122 The Descent of Man. Part I. 

reasoning. Hence the strangest cnstoms and superstitions, in 
complete opposition to* tlie true welfare and happiness of man- 
kind, have become all-powerful throughout the world. We see 
this in the horror felt by a Hindoo who breaks his caste, and 
in many other such cases. It would be difficult to distinguish 
between the remorse felt by a Hindoo who has yielded to the 
temptation of eating unclean food, from that felt after committing 
a theft ; but the former would probably be the more severe. 

How so many absurd rules of conduct, as well as so many 
absurd religious beliefs, have originated, we do not know ; 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, whilst the brain is impressible, appears to acquire almost 
the nature of an instinct ; and the very essence of an instinct is 
that it is followed independently of reason. Neither can we say 
why certain admirable Yirtues; such as the love of truth, are 
much more highly appreciated by some savage tribes than by 
others ;^^ nor, again, why similar diiferences prevail even amongst 
highly civihsed 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 

Notwithstanding many sources of doubt, man can generally 
and readily distinguish between the higher and lower moral 
rules. The higher are founded on the social instincts, and relate 
to the welfare of others. They are supported by the approbation 
of our fellow-men and by reason. The lower rules, though some 
of them when implying self-sacrifice hardly deserve to be called 
lower, relate chiefly to self, and arise from public opinion, ma- 
tured by experience and cultivation ; for they are not practised 
by rude tribes. 

As man advances' in civilisation, and small tribes are united 
into . larger communities, the simplest reason would tell each 
individual that he ought to extend his social instincts and 
sympatlries to all the members of the same nation, though 
personally unknown to him. This point being once reached, 
there is only an artificial barrier to prevent his sympathies 
extending to the men of all nations and races. If, indeed, such 
men are separated from him by great differences in appearance 

*^ Good instances are given by in his 'Contributions to the Theory 
Mr. Wallace in 'Scientific Opinion/ of Natural Selection,' 1870, p. 353. 
Sept. 15, 1869 ; and more fully 

Chap. IV. Moral Sense. 123 

or habits, experience ■unfortunately shews us how long it is, 
before we look at them as our fellow-creatures. Sympathy 
beyond the confines of man, that is, humanity to the lower 
animals, seems to be one of the latest moral acquisitions. It is 
apparently unfelt by savages, except towards their pets. How 
little the old Romans knew of it is shewn by their abhorrent 
gladiatorial exhibitions. The very idea of humanity, as tar as I 
could observe, w^as new to most of the Gauchos of the Pampas. 
This virtue, one of the noblest with which man is endowed, 
seems to arise incidentally from our sympathies becoming more 
tender and more widely diffused, until they are extended to all 
sentient beings. As soon as this virtue is honoured and practised 
by some few men, it spreads through instruction and example 
to the young, and eventually becomes incorporated in public 
opinion . 

The highest possible stage in moral culture is when we re- 
cognise that w^c 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 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 organised and consolidated through all 
" past generations of the human race, have been producing. 
" corresponding modifications, which, by continued transmission 
" and accumulation, have become in us certain faculties of 
" moral intuition— certain emotions responding to right and 
" wrong conduct, w^hich 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 coinci- 
dence for the tendency occurring in two or three members of 

^^ Tennyson, 'Idylls of the King,* Aurelius was born a.d. 121. 

p. 244. ••« Letter to Mr. Mill in B;tiu's 

** ' The Thoughts of the Emperor ' Mental and Moral Science,' 18(J8, 

M. Aurelius Antoninus,' Eng. trans- p. 722. 
lat., 2ud edit., 1869, p. 112. Marcus 

124 The Descejtt of Man. Paet I. 

the same family. If bad tendencies are transmitted, it is pro- 
bable that good ones are likewise transmitted. That the state 
of the body by affecting the 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 shewn by the " perversion 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 ten- 
dencies, we cannot understand the differences believed to exist in 
this respect between the various races of mankind. 

Even the partial transmission of virtuous tendencies would 
be an immense assistance to the primary impulse derived directly 
and indirectly from the social instincts. Admitting for a moment 
that virtuous tendencies are inherited, it appears probable, at 
least in such cases as chastity, temperance, humanity to animals, 
&c., that they become first impressed on the mental organization 
through habit, instruction and example, continued during 
several generations in the same family, and in a quite subordinate 
degree, or not at all, by the individuals possessing such virtues 
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 Hindoo 
for unclean food, ought on the same principle to be transmitted. 
I have not met with any evidence in support of the transmission 
of superstitious customs or senseless habits, although in itself it 
is perhaps not less probable than that animals should acquire 
inherited tastes for certain kinds of food or fear of certain foes. 

Finally the social instincts, Avhich no doubt were acquired by 
man as by the lower a-nimals for the good of the community, 
will from the first have given to him some wish to aid his 
fellows, some feeling of sympathy, and have compelled him to 
regard their approbation and disapprobation. Such impulses 
will have served him at a very early period as a rude rule of 
right and wrong. But as man gradually advanced in intellectual 
power, and was enabled to trace the more remote consequences 
of his actions ; as he acquired sufficient knowledge to reject 
baneful customs and superstitions; as he regarded more and 
more, not only the welfare, but the happiness of his fellow-men ; 
as from habit, following on beneficial experience, instruction 
and example, his sympathies became more tender and widely 
diffused, extending to men of all races, to the imbecile, maimed, 

*^ Maudsley, 'Body and Mind,' 1870, p. 60. 

Chap. IV. Summary. 125 

and otlier useless members of society, and finally to the lower 
animals,— so would the standard of his morality rise higher and 
higher. And it is admitted by moralists of the derivative 
school and by some intuitionists, that the standard of morality 
has risen since an early period in the history of man/** 

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 iwwcrful instincts or desires, when left unsatisfied or 
baulked. We compare the weakened impression of a past 
temptation with the ever present social instincts, or with habits, 
gained in early youth and strengthened during our whole lives, 
until they have become almost as strong as instincts. If with 
the temptation still before us we do not yield, it is because 
either the social instinct or some custom is at the moment 
predominant, or because we have learnt that it will appear to us 
hereafter the stronger, when comj)ared with the weakened im- 
pression of the temptation , and we realise that its violation would 
cause us suffering. Looking to future generations, there is no 
cause to fear that the social instincts will grow weaker, and we 
may expect that virtuous habits will grow stronger, becoming 
perhaps fixed by inheritance. In this case the struggle between 
our higher and lower impulses will be less severe, and virtue 
will be triumphant. 

Summary of the last two Chapters.— Thci'O can be no doubt that 
the difference between the mind of the lowest man and that of 
the highest animal is immense. An anthropomorphous ape, if 
he could take a dispassionate view of his own case, would admit 
that though he could form an artful plan to plunder a garden — 
though he could use stones for fighting or for breaking open 
nuts, yet that the thought of fashioning a stone into a tool was 

■•' A writer in the 'North British coincide therein. 

Review' (July 1869, p. o.'jI), well *" See his remarkable work on 

capable of forming a sound judg- ' Hereditary Genius,* 18G9, p. 349. 

ment, expresses himself strongly in The Duke of Argyll (' Primeval 

favour of this conclusion. Mr. Man,' 1809, p. 188) has some good 

Lecky ('Hist, of Morals,' vol. i. p. remarks on the contest in man's 

143) seems to a certain extent to nature between right and wrong. 

1 26 The Descent of Man. Part I. 

quite beyond liis scope. Still less, as he would admit, could lie 
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 declare that they 
could and did admire the beauty of the coloured skin and fur of 
their partners in marriage. They would admit, that though they 
could make other apes understand by cries some of their per- 
ceptions and simpler wants, the notion of expressing definite ideas 
by definite sounds had never crossed theii' minds. They might 
insist that they were ready to aid their fellow-apes of the same 
troop in many ways, to risk their lives for them, and to take 
charge of their orphans ; but they would be forced to acknow- 
ledge that disinterested love for all living creatures, the 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 intuitions, the 
various emotions and faculties, such as love, memory, attention, 
curiosity, imitation, reason, &c., of w^hich man boasts, may be 
found in an incipient, or even sometimes in a well- developed 
condition, in the lower animals. They are also capable of some 
inherited improvement, as we see in the domestic dog compared 
with the wolf or jackal. If it could be proved that certain high 
mental powers, such as the formation of general concepts, self-con- 
sciousness, &c., were absolutely peculiar to man, which seems 
extremely doubtful, it is not improbable that these qualities are 
merely the incidental results of other highly-advanced intel- 
lectual faculties; and these again mainly the result of the 
continued use of a perfect language. At what age does the 
new-born infant possess the power of abstraction, or become 
self-conscious, and reflect on its own existence ? We cannot 
answer ; nor can we answer in regard to the ascending organic 
scale. The half-art, half-instinct of language still bears the 
stamp of its gradual evolution. The ennobhng belief in God is 
not universal with man; and the belief in spiritual agencies 
naturally follows from other mental powers. The moral sense 
perhaps affords the best and highest distinction between man and 
the lower animals ; but I need say nothing on this head, as I 
have so lately endeavoured to shew that the social instincts, — 
the prime principle of man's moral constitution ^" — with the aid 
of active intellectual powers and the effects of habit, naturally lead 
to the golden rule, " As ye would that men should do to you, do 
ye to them likewise ;'' and this lies at the foundation of morality. 

so ' The Tlioughts of Marcus Aurelius,' &c., p. 139. 

TiiAP. V. Ijitellcctnal Faculties. 1 27 

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 evolu- 
tion is at least possible, ought not to be denied, for we daily sec 
these faculties developing in every infant ; and we may trace a 
perfect gradation from tlie mind of an utter idiot, lower than 
that of an animal low in the scale, to the mind of a Newton. 


On the Development of the Intellectual and Moral 
Faculties during Primeval and Civilised Times. 

Ailvanceniont of the intellectual powers through natural selection — 
Importance of imitation — Social and moral faculties — Their develop- 
ment within the limits of the same tribe — Natural selection as affecting 
civilised nations — Evidence that civilised nations were once barbarous. 

The subjects to be discussed in this chapter are of the highest 
interest, but are treated by me in an imperfect and fragmentary 
manner. Mr. Wallace, in an admirable paper before referred to,' 
argues that man, after he had partially acquired those intel- 
tectual and moral faculties which distinguish him from the 
lower animals, would have been but little liable to bodily 
modifications through natural selection or any other means. 
For man is enabled through his mental faculties '' to keep with 
" an unchanged body in harmony with the changing universe." 
He has great power of adapting his habits to new conditions of 
life. He invents weapons, tools, and various stratagems to 
procure food and to defend himself. When he migrates into a 
colder climate he nses clothes, builds sheds, and makes fires ; 
and by the aid of fire cooks food otherwise indigestible. Ho 
aids his fellow-men in many ways, and anticipates future events 
Even at a remote period he practised some division of labour. 

The lower animals, on the other hand, must have their bodily 
structure modified in order to survive under greatly changed 
conditions. They must be rendered stronger, or acquire more 
effective teeth or claws, for defence against new enemies; or 
they must be reduced in size, so as to escape detection and 
danger. When they migrate into a colder climate, they must 
become clothed with thicker fur, or have their constitutions 
altered. If they fail to be thus modified, they will cease to 

• ' Antliropological Review,' ^'^ay 13G4, p. clviii. 

128 The Descent of Man. Part I. 

The case, however, is widely different, as Mr. Wallace has 
with justice inssted, in relation to the intellectnal and moral 
faculties of man. These faculties are variable; and we have 
every reason to believe that the variations tend to be inherited. 
Therefore, if they were formerly of high importance to primeval 
man and to his ape-like progenitors, they would have been 
perfected or advanced through natural selection. Of the high 
importance of the intellectual faculties there can be no doubt, 
for man mainly owes to them his predominant position in the 
world. We can see, that in the rudest state of society, the 
individuals who were the most sagacious, who invented and used 
the best weapons or traps, and who were best able to defend 
themselves, would rear the gi-eatest number of offspring. The 
tribes, which included the largest number of men thus endowed, 
would increase in number and supplant other tribes. Numbers 
depend primarily on the means of subsistence, and this depends 
partly on the physical nature of the country, but in a much higher 
degree on the arts which are there practised. As a tribe increases 
and is victorious, it is often still further increased by the ab- 
sorption of other tribes.^ The stature and strength of the men 
of a tribe are likewise of some importance for its success, and 
these depend in part on the nature and amount of the food which 
can be obtained. In Europe the men of the Bronze period were 
supplanted by a race more powerful, and, judging from their 
sword-handles, with larger hands f but their success was pro- 
bably still more due to their superiority in the arts. 

All that we Imow about savages, or may infer from their 
traditions and from old monuments, the history of which is quite 
forgotten by the present inhabitants, shew that from the remotest 
times successful tribes have supplanted other tribes. Eelics of 
extinct or forgotten tribes have been discovered throughout the 
civilised regions of the earth, on the wild plains of America, and 
on the isolated islands in the Pacific Ocean. At the i^resent day 
civilised nations are everywhere supplanting barbarous nations, 
excepting where the climate opposes a deadly barrier; and they 
succeed mainly, though not exclusively, through their arts, which 
are the products of the intellect. It is, therefore, highly probal^le 
that with mankind the intellectual faculties have been mainly 
and gradually perfected through natural selection; and this con- 
clusion is sufficient for our purpose. Undoubtedly it would 
be interesting to trace the development of each separate faculty 

2 After a time the members or 1861, p. 131), that they are the co- 
tribes which are absorbed into descendants of the same ancestors, 
another tribe assume, as Sir Henry ^ Morlot, ' Soc. Vaud. Sc. Nat.' 
Maine remarks ('Ancient Law,' 1860, p. 294. 

Chap. V. Moral Faculties. 129 

from the state in which it exists in the lower animals to that in 
which it exists in man ; but neither my ability nor knowledge 
permits the attempt. 

It deserves notice that, as soon as the progenitors of man 
became social (and this probably occurred at a very early period), 
the principle of imitation, and reason, and experience would 
have increased, and much modified the intellectual powers in a 
way, of which we see only traces in the lower animals. Apes are 
much given to imitation, as are the lowest savages; and the 
simple fact previously referred to, that after a time no animal 
can be caught in the same place by the same sort of trap, shews 
that animals learn by experience, and imitate the caution of 
others. Now, if some one man in a tribe, more sagacious than 
the others, invented a new snare or weapon, or other means of 
attack or defence, the plainest self-interest, without the assistance 
of much reasoning power, would prompt the other members to 
imitate him ; and all would thus profit. The habitual practice 
of each new art must likewise in some slight degree strengthen 
the intellect. If the new invention were an important one, the 
tribe would increase in number, spread, and sujDplant other 
tribes. In a tribe thus rendered more numerous there would 
always be a rather greater chance of the birth of other superior 
and inventive members. If such men left children to inherit 
their mental superiority, the chance of the birth of still more 
ingenious members would be somewhat better, and in a very 
small tribe decidedly better. Even if they left no children, the 
tribe would still include their blood- relations ; and it has been 
ascertained by agriculturists * that by preserving and breeding 
from the family of an animal, which when slaughtered was 
found to be valuable, the desired character has been obtained. 

Turning now to the social and moral faculties. In order that 
primeval men, or the ape-like i)regenitors of man, should become 
social, they must have acquired the same instinctive feelings, 
which impel other animals to live in a body ; and they no doubt 
exhibited the same general disposition. They would have felt 
uneasy when separated from their comrades, for whom they 
would have felt some degree of love ; they would have warned 
each other of danger, and have given mutual aid in attack or 
defence. All this implies some degree of sympathy, fidelity, and 
courage. Such social qualities, the paramount importance of 
which to the lower animals is disputed by no one, were no doubt 

* I have given iustanccs in my * Variation of Animals ujiJer Domestica- 
tion,' vol. ii. p. 196. 


1 30 The Descent of Man. Part 1. 

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 gi-eat number of courageous, sjTnpathetic 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, fidehty and courage must 
be. The advantage which disciplined soldiers have over undis- 
ciplined hordes follows chiefly from the confidence which each 
man feels in his comrades. Obedience, as IMr. Bagehot has well 
shewTi,^ 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 ti*ibe rich in 
the above qualities would spread and be victorious 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 social 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 standard of ex- 
cellence raised ? It is extremely doubtful whether the offspring 
of the more sympathetic and benevolent parents, or of those 
who were the most faithful to their comrades, would be reared 
in greater numbers than the children of selfish and treacherous 
parents belonging to the same tribe. He who was ready to 
sacrifice his life, as many a savage has been, rather than betray 
his comrades, would often leave no offspring to inherit his noble 
nature. The bravest men, who were always willing to come to 
the front in war, and who freely risked their lives for others, 
would on an average perish in larger numbers than other men. 
Therefore it hardly seems probable, that the number of men 
gifted with such virtues, or that the standard of their excellence, 
could be increased through natural selection, that is, by the 
survival of the fittest ; for we are not here speaking of one tribe 
being victorious over another. 

Although the circumstances, leading to an increase in the 
number of those thus endowed within the same tribe, are too 
complex to be clearly followed out, we can trace some of the 
probable steps. In the first place, as the reasoning powers and 

* See a remarkable series of arti- April 1, 1868 ; July 1, 1869, since 
cles on ' Physics and Politics ' in the separately published. 
' Fortnightly Review,' Nov. 1867 ; 

Chap. V. Moral Facilities. 1 3 1 

foresight of the members became improved, each man would' 
soon learn that if ho aided his fellow-men, he would commonly 
receive aid in return. From this low motive he might acquire 
the habit of aiding his fellows ; and the habit of performing 
benevolent actions certainly strengthens the feeling of sympathy 
which gives the first impulse to benevolent actions. Habits, 
moreover, followed during many generations probably tend to 
be inherited. 

But another and much more powerful stimulus to the de- 
velopment of the social virtues, is afforded by the praise and the 
blame of our fellow-men. To the instinct of sympathy, as we have 
already seen, it is primarily due, that we habitually bestow both 
praise and blame on others, whilst we love the former and dread 
the latter when applied to ourselves ; and this instinct no doubt 
was originally acquired, like all the other social instincts, through 
natural selection. At how early a period the progenitors of man 
in the course of their development, became capable of feehngand 
being impelled by, the praise or blame of their fellow-creatures, 
we caijnot of course say. But it appears that even dogs appre- 
ciate encouragement, praise, and blame. The rudest savages 
feel the sentiment of glory, as they clearly show by preserving 
the trophies of their prowess, by their habit of excessive boasting, 
and even by the extreme care which they take of their per- 
sonal appearance and decorations ; for unless they regarded the 
opinion of their comrades, such habits would be senseless. 

They certainly feel shame at the breach of some of their lesser 
rules, and apparently remorse, as shewn by the case of the 
Australian who grew thin and could not rest from having 
delayed to murder some other woman, so as to propitiate his dead 
wife's spirit. Though I have not met with any other recorded 
case, it is scarcely credible that a savage, who will sacrifice his 
life rather than betray his tribe, or one who will deliver himself 
up as a prisoner rather than break his parole,*^ 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. To do 
good unto others — to do unto others as ye would they should do 
unto you— is the foundation-stone of morality. It is, therefore, 
hardly possible to exaggerate the importance during rude times 

^ Mr. Wallace gives cases in of Natural Seleotioa,' 1870, p. 
bla 'Contributions to the Theory 354. 

132 The Descent of Man. Part 1. 

of the loYe of praise and the dread of blame. A man who was 
not impelled by any deep, instinctive feeling, to sacrifice his 
life for the good of others, yet was roused to such actions by a 
sense of glory, would by his example excite the same wish for 
glory in other men, and would strengthen by exercise the noble 
feeling of admiration. He might thus do far more good to his 
tribe than by begetting offspring with a tendency to inherit his 
own high character. 

With increased experience and reason, man perceives the 
more remote consequences of his actions, and the self-regarding 
virtues, such as temperance, chastity, &c., which during early 
times are, as we have before seen, utterly disregarded, come to 
be highly esteemed or even held sacred. I need not, however, 
repeat what I have said on this head in the fourth chapter. 
Ultimately our moral sense or conscience becomes a highly 
complex sentiment— originating in the social instincts, largely 
guided by the approbation of our fellow-men, ruled by reason, 
self-interest, and in later times by deep religious feelings, and 
confirmed by instruction and habit. ' * 

It must not be forgotten that although a high standard of 
morality gives but a slight or no advantage to each individual 
man and his children over the other men of the same tribe, yet 
that an increase in the number of well-endowed men and an 
advancement iii the standard of morality will certainly give an 
immense advantage to one tribe over another. A tribe including 
many members who, from possessing in a high degTee the spmt 
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 morahty 
is one important element in their success, the standard of 
morality and the number of well- en do wed men will thus every- 
where tend to rise and increase. 

It is, however, very difficult to form any judgment why one 
particular tribe and not another has been successful and has 
risen in the scale of civilisation. Many savages are in the same 
condition as when first discovered several centuries ago. As Mr. 
Bagehot has remarked, we are apt to look at progress as normal 
in human society ; but history refutes this. The ancients did 
not even entertain the idea, nor do the Oriental nations at the 
present day. According to another high authority. Sir Henry 
Maine,^ " the greatest part of mankind has never shewn a 

' 'Ancient Law,' 1861, p. 22. nightly Review,' April 1, 1S68, p. 
For Mr. Bagehot's remarks, ' Fort- 452. 

Chap. V. Civilised Nations. 


" particlo of desire that its civil institutions should be iui- 
" proved." Progress seems to depend on many concurrent 
favourable conditions, far too complex to be followed out. But 
it has often been remarked, that a cool climate, from leading to 
industry and to the various arts, has been highly favourable 
thereto. The Esquimaux, pressed by hard necessity, have 
succeeded in many ingenious inventions, but their climate has 
been too severe for continued progress. Nomadic habits, whether 
over wide plains, or through the dense forests of the tropics, or 
along the shores of the sea, have in every case been highly 
detrimental. "Whilst observing the barbarous inhabitants of 
Tierra del Fuego, it struck me .that the possession of some 
property, a fixed abode, and the union of many families under a 
chief, were the indispensable requisites for civilisation. Such 
habits almost necessitate the cultivation of the ground ; and the 
first steps in cultivation would j^robably result, as I have else- 
where shewu,^ from some such accident as the seeds of a fruit- 
tree falling on a heap of refuse, and producing an unusually fine 
variety. The problem, however, of the first advance of savages 
towards civilisation is at present much too difficult to be solved. 

Natural Selection as affecting Civilised Nations. — I have hitherto 
only considered the advancement of man from a semi-human 
condition to that of the modern savage. But some remarks on 
the action of natural selection on civilised nations may be worth 
adding. This subject has been ably discussed by Mr. W. E. 
Greg,^ and previously by Mr. Wallace 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 civilised men, on the other hand, do our utmost to check the 
process of elimination ; we build asylums for the imbecile, the 
maimed, and the sick ; we institute poor-laws ; and our medical 

" 'The Variation of Animals and 1869, and by Mr. E. Ray Lankester 

Plants under Domestication,' vol. i. in his 'Comparative Longevitv,' 

p. 309. 1870, p. 128. Similar views ap- 

* 'Eraser's Magazine,' Sept. 1868, peared previously in the 'Austra- 

p. 353. This article seems to have lasian,' July* 13, 1867. I have 

struck many persons, and has given borrowed ideas from several of these 

rise to two remarkable essays and a writers. 

rejoinder in the ' Spectator,' Oct. ^'^ For Mr. Wallace, see ' Anthro- 

3rd and 17th, 1868. It has also polog. Review,' as before cited. Mr. 

been discussed in the 'Q. Journal of Galton in ' Macmillan's Magazine,' 

Science,' 1869, p. 152, and by Mr. Aug. 1865, p. 318 ; also his great 

Lawson Tait in the 'Dublin Q. work, ' Hereditary Genius,' 1870. 
Journal of Medical Science,' Feb. 

1 34 The Descent of Man. Part I. 

men exert their utmost skill to save the Kfe of every one to the 
last moment. There is reason to belieye that vaccination has 
preserved thousands, who from a weak constitution would 
formerly have succumbed to small-pox. Thus the weak members 
of civilised societies propagate their kind. No one who has 
attended to the breeding of domestic animals will doubt that 
this must be highly injurious to the race of man. It is surprising 
how soon a want of care, or care wrongly directed, leads to the 
degeneration of a domestic race ; but excepting in the case of 
man himself, hardly any one is so ignorant as to allow his 
worst animals to breed. 

The aid which we feel impelled to give to the helpless is mainly 
an incidental result of the instinct of sympathy, which was 
originally acquired as pai*t of the social instincts, but sub- 
sequently rendered, in the manner previously indicated, more 
tender and more widely diifused. Nor could we check our 
sympathy, even at the urging of hard reason, without deteriora- 
tion in the noblest part of our nature. The surgeon may harden 
himself whilst performing an operation, for he knows that he is 
acting for the good of his patient ; but if we were intentionally 
to neglect the weak and helpless, it could only be for a con- 
tingent benefit, with an overwhelming present evil. We must 
therefore bear the undoubtedly bad eflfects of the weak surviving 
and propagating their kind ; but there appears to be at least one 
check in steady action, namely that the weaker and inferior 
members of society do not marry so freely as the sound ; and 
this check might be indefinitely increased by the weak in 
body or mind refraining from marriage, though this is more to be 
hoped for than expected. 

In every country in which a large standing army is kept up, 
the finest young men are taken by the conscription or are 
enlisted. They are thus exposed to early death during war, are 
often tempted into vice, and are prevented from marrying during 
the prime of life. On the other hand the shorter and feebler men, 
with poor constitutions, are left at home, and consequently have 
a much better chance of marrying and jDropagating their kind.^^ 

Man accumulates property and bequeaths it to his children, 
so that the children of the rich have an advantage over the poor 
in the race for success, independently of bodily or mental su- 
periority. On the other hand, the children of parents who are 
short-lived, and are therefore on an average deficient in health 
and vigour, come into their property sooner than other children, 

" Prof. H, Fick (' Einfluss der on this head, and on other such 
Naturwissenschaft auf das Eecht,' points. 
June, 1872) has some good remarks 

Chap. V. Civilised Nations. 1 3 5 

and will be likely to marry earlier, and leave a larger number of 
offspring to inherit their inferior constitutions. But the in- 
heritance of property by itself is very far from an evil ; for 
without the accumulation of capital the arts could not progress ; 
and it is chiefly through their power that the civilised races have 
extended, and arc now everywhere extending their range, so as 
to take the place of the lower races. Nor does the moderate 
accumulation of wealth interfere with the process of selection. 
When a poor man becomes moderately rich, his children enter 
trades or professions in which there is struggle enough, so that 
the able in body and mind succeed best. The presence of a body 
of well-instructed men, who have not to labour for their daily 
bread, is important to a degree which cannot be over-estimated ; 
as all high intellectual work is carried on by them, and on such 
work, material jirogress of all kinds mainly depends, not to 
mention other and higher advantages. No doubt wealth when 
very gi-eat tends to convert men into useless drones, but their 
number is never large; and some degree of elimination here 
occurs, for we daily see rich men, who happen to be fools or 
profligate, squandering away their wealth. 

Primogeniture with entailed estates is a more direct evil, 
though it may formerly have been a great advantage by the 
creation of a dominant class, and any government is better 
than none. Most eldest sons, though they may be weak in body 
or mind, marry, whilst the younger sons, however superior 
in these respects, do not so generally marry. Nor can worth- 
less eldest sons with entailed estates squander their wealth. 
But here, as elsewhere, the relations of civilised life are so 
complex that some compensatory checks intervene. The men 
who are rich through primogeniture are able to select genera- 
tion after generation the more beautiful and charming women ; 
and these must generally be healthy in body and active in 
mind. The evil consequences, such as they may be, of the 
continued preservation of the same line of descent, without any 
selection, are checked by men of rank always wishing to increase 
their wealth and power; and this they effect by marrying 
heiresses. But the daughters of parents who have produced 
single children, are themselves, as Mr. Galton^^ has shewn, apt to 
be sterile ; and thus noble families are continually cut off in the 
direct line, and their wealth flows into some side channel ; but 
unfortunately this channel is not determined by superiority of 
any kind. 

Although civilisation thus checks in many ways the action of 

>2 'Hereditary Genius,' 1870, pp. 132-140. 

136 The Desce7it of Man. Part I. 

natural selection, it apparently favours the better development 
of the body, by means of good food and the freedom from occa- 
sional hardships. This may be inferred from civilised men 
having been found, wherever compared, to be physically 
stronger than savages.'^ They appear also to have equal powers 
of endurance, as has been proved in many adventurous ex- 
peditions. Even the great luxury of the rich can be but little 
detrimental ; for the expectation of life of our aristocracy, at all 
ages and of both sexes, is very httle 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 occupations, 
owing to the great division of labour, a very small one. Hence 
in civilised nations there will be some tendency to an increase 
both in the number and in the standard of the intellectually 
able. But I do not wish to assert that this tendency may not be 
more than counterbalanced in other ways, as by the multiplica- 
tion of the reckless and improvident ; but even to such as these, 
ability must be some advantage. 

It has often been objected to views like the foregoing, that the 
most eminent men who have ever lived have left no offspring to 
inherit their great intellect. Mr. Galton says,^^ " I 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, shewn that men of eminence are by no means 
" so." Great lawgivers, the founders of beneficent rehgions, 
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 pre- 
servation of strongly-marked and rare anomalies, that leads to 
the advancement of a species.^'' So it will be with the intellectual 
faculties, since the somewhat abler men in each grade of society 

'^ Quatrefages, 'Revue des Cours 1870, p. 115. 
Scientifiques,' 1867-68, p. 659. i^ < Hereditary Genius,' 1870, p. 

^■^ See the fifth and sixth columns, 330. 
compiled from good authorities, in ^*^ ' Origin of Species ' (fifth edi- 

the table given in Mr. E. R, Lan- tion, 1869), p. lO-l. 
kester's ' Comparative Longevity,' 

Chap. V. • Civilised Nations. ■ 137 

succeed rather better than the less able, and consequently 
increase in number, if not otherwise prevented. When in 
any nation the standard of intellect and the number of intel- 
lectual men have increased, we may expect from the law of 
the deviation from an average, that prodigies of genius will, as 
shewn by Mr. Galton, appear somew^hat more frequently than 

In regard to the moral qualities, some elimination of the 
worst dispositions is always in progress even in the most civilised 
nations. Malefactors are executed, or imprisoned for long 
periods, so that they cannot freely transmit their bad qualities. 
Melancholic and insane persons are confined, or commit suicide. 
Violent and quarrelsome men often come to a bloody end. The 
restless who will not follow any steady occupation— and this 
relic of barbarism is a great check to civilisation ^^ — emigrate to 
newly-settled countries, where they prove useful pioneers. In- 
temperance is so highly destructive, that the expectation of life 
of the intemperate, at the age of thirty for instance, is only 13-8 
years ; whilst for the rural labourers of England at the same age 
it is 40*59 years.^^ Profligate women bear few children, and 
profligate men rarely marry ; both suifer from disease. In the 
breeding of domestic animals, the elimination of those individuals, 
though few in number, which are in any marked manner inferior, 
is by no means an unimportant element towards success. This 
especially holds good with injurious characters which tend to 
reappear through reversion, such as blackness in sheep; and 
with mankind some of the worst dispositions, W'hich occasionally 
without any assignable cause make their appearance in families, 
may perhaps be reversions to a savage state, from which we are 
not removed by very many generations. This view seems 
indeed recognised in the common expression that such men are 
the black sheep of the family. 

With civilised nations, as far as an advanced standard of 
morality, and an increased number of fairly good men are con- 
cerned, natural selection apparently effects but little ; though 
the fundamental social instincts w^ere originally thus gained. 
But I have already said enough, whilst treating of the lower 
races, on the causes which lead to the advance of morality, 
namely, the approbation of our fellows-men — the strengthening 

^^ 'Hereditary Genius,' 1870, p. Xeison's * Vital Statistics.' In re- 

347. gard to profligacy, see Dr. Farr, 

" E. Ray Lankester, ' Compara- 'Influence of Marriage on Mor- 
tive Longevity,' 1870, p. 115, Tiie tality,' 'Nat. Assoc, for the Promo- 
table of the intemperate is from tion of Social Science,' 1858. 

138 The Descent of Man. Part T. 

of our sympathies by habit — example and imitation — reason — 
experience, and even self-interest — instruction during youth, and 
rehgious feelings. 

A most important obstacle in civilised conntries 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 degraded by vice, almost invari- 
ably marry early, whilst the careful and frugal, who are generally 
otherwise virtuous, marry late in life, so that they may be able 
to support themselves and their children in comfort. Those who 
marry early produce within a given period not only a greater 
number of generations, but, as shewn by Dr. Duncan,^*^ they pro- 
duce many more children. The children, moreover, that are 
born by mothers during the prime of life are heavier and larger, 
and therefore probably more vigorous, than those born at other 
periods. Thus the reckless, degraded, and often vicious members 
of society, tend to increase at a quicker rate than the provident 
and generally virtuous members. Or as Mr. Greg puts the case : 
" The careless, squalid, unaspiring Irishman multiplies like 
" rabbits : the frugal, foreseeing, self-respecting, ambitious Scot, 
" stern in his morality, spiiitual in his faith, sagacious and dis- 
" ciplined in his intelligence, passes his best years in struggle 
" and in celibacy, marries late, and leaves few behind him. 
" Given a land originally peopled by a thousand Saxons and a 
" thousand Celts — and in a dozen generations five-sixths of the 
" population would be Celts, but five-sixths of the property, of 
" the power, of the intellect, would belong to the one-sixth of 
'' Saxons that remained. In the eternal ' struggle for existence,' 
" it would be the inferior and le»8 favoured race that had pre- 
" vailed— and prevailed by virtue not of its good qualities but of 
" its faults." 

There are, however, some checks to this downward tendency. 
We have seen that the intemj)erate 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 

'^ * Fraser's Magazine,' Sept. title of ' Fecundity, Fertility, and 

1868, p. 353. 'Macmillan's Maga- Sterility,' 1871. See, also, Mr. 

zine, Aug. 1865, p. 318. The Rev. Galton, 'Hereditary Genius,' pp. 

F. W. Farrar (' Fraser's Mag.' Aug. 352-357, for observations to the 

1870, p. 264) takes a different view. above effect. 

2*^ ' On the Laws of the Fertility 2' ' Tenth Annual Report of 

of Women,' in ' Transact. Royal Births, Deaths, &c., in Scotland,' 

Soc' Edinburgh, vol. xxiv. p. 287 ; 1867, p. xxix. 
now published separately under the 

(jiiAP. V. Civilised Nations. 1 39 

ages the death-rate is higher in towns tlian 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 re- 
tui-ns 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 w^ould be only 
slightly lessened. 

It was established from an enormous body of statistics, taken 
during 1853, that the unmarried men throughout France, 
between the ages of twenty and eighty, die in a much larger 
proportion than the married : for instance, out of every 1000 
unmarried men, between the ages of twenty and thirty, 11-3 
annually died, whilst of the married only 6'5 died.^^ A similar 
law was proved to hold good, during the years 18G3 and 1864, 
with the entire population above the age of twenty in Scotland : 
for instance, out of every 1000 unmarried men, between the ages 
of twenty and thirty, 14-97 annually died, whilst of the married 
only 7-21: 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 distant 
" attempt at sanitary improvement." He considers that the 
lessened mortality is the direct result of " marriage, and the 
" more regular domestic habits which attend that state." He 
admits, however, that the intemperate, profligate, and criminal 
classes, whose duration of life is low, do not commonly marry ; 
and it must likewise be admitted that men with a weak constitu- 

^ These quotations are taken from the same striking paper, 

from our highest authority on such -* 1 have taken the mean of the 

questions, namely, Dr. Farr, in his quinquennial means, given in ' The 

paper 'On the Influence of Mar- Tenth Annual Report of Births, 

riage on the Mortality of the French Deaths, &c., in Scotland,' 18G7. 

People,' read before the Nat. Assoc. The quotation from Dr. Stark is 

for the Promotion of Social Science, copied from an article in the ' Daily 

1858. News,' Oct. 17th, 18G8, which Dr. 

23 Dr. Farr, ibid. The quota- Farr considers very carefully writ- 

tioas given below are extracted ten. 

140 The Descent of Man. Part I. 

tion, ill health, or any great infirmity in body or mind, will often 
not wish to marry, or will be rejected. L)r. Stark seems to have 
come to the conclusion that marriage in itself is a main cause of 
prolonged life, from finding that aged married men still have a 
considerable advantage in this respect over the unmarried of the 
same advanced age ; but every one must have known instances 
of men, who with weak health during youth did not marry, and 
yet have survived to old age, though remaining weak, and there- ' 
fore always with a lessened chance of life or of marrying. There 
is another remarkable circumstance which seems to support Dr. 
Stark's conclusion, namely, that widows and widowers in France 
suffer in comparison with the married a very heavy rate of mor- 
tality ; but Dr. Farr attributes this to the poverty and evil habits 
consequent on the disruption of the family, and to grief. On 
the whole we may conclude with Dr. Farr that the lesser mortahty 
of married than of unmarried men, which seems to be a general 
law, "is mainly due to the constant elimination of imperfect 
" types, and to the skilful selection of the finest individuals out 
" of each successive generation ;" the selection relating only to 
the marriage state, and acting on all corporeal, intellectual, and 
moral qualities.^^ We may, therefore, infer that sound and 
good men who out of prudence remain for a time unmarried, do 
not suffer a high rate of mortality. 

If the various checks specified in the two last paragraphs, and 
perhaps others as yet unknown, do not prevent the reckless, the 
vicious and otherwise inferior members of society from increas- 
ing at a quicker rate than the better class of men, the nation will 
retrograde, as has too often occurred in the history of the world. 
We must remember that progress is no invariable rule. It is 
very diflScult to say why one civilised nation rises, becomes more 
l^owerful, and sjDreads more widely, than another ; or why the 
same nation progresses more quickly at one time than at another. 
We can only say that it depends on an increase in the actual 
number of the population, on the number of the men endowed 
with high intellectual and moral faculties, as well as on their 
standard of excellence. Corporeal structure appears to have 
little influence, except so far as vigour of body leads to vigour of 

It has been urged by several writers that as high intellectual 
powers are advantageous to a nation, the old Greeks, who stood 
some grades higher in intellect than any race that has ever 

25 Dr. Duncan remarks (' Fecund- '■'■ from the unmarried side to the 

ity, Fertility,' &c., 1871, p. 334) on " married, leaving the unmarried 

this subject; "At every age the "columns crowded with the sickly 

" healthy and beautiful go over " and unfortunate." 

Chap V. Civilised Nations. 1 41 

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 assump- 
tion, so often made with respect to corporeal structures, that 
there is some innate tendency towards continued development in 
mind and body. But development of all kinds depends on many 
concurrent favourable circumstances. Natural selection acts 
only tentatively. Individuals and races may have acquired cer- 
tain indisputable advantages, and yet have perished from failing 
in other characters. The Greeks may have retrograded from a 
want of coherence between the many small states, from the small 
size of their whole country, from the practice of slavery, or from 
extreme sensuality ; for they did not succumb until " they were 
" enervated and corrupt to the very core." '^ The western nations 
of Europe, who now so immeasurably surpass their former savage 
progenitors, and stand at the summit of civilisation, owe little 
or none of their superiority to direct inheritance from the old 
Greeks, though they owe much to the written works of that 
wonderful people. 

Who can positively say why the Spanish nation, so dominant 
at one time, has been distanced in the race. The awakening of 
the nations of Europe from the dark ages is a still more perplex- 
ing problem. At that early period, as Mr. Galton has remarked, 
almost all the men of a gentle nature, those given to meditation 
or culture of the mind, had no refuge except in the bosom of 
a Church which demanded celibacy ;^^ and this could hardly 
fail to have had a deteriorating influence on each successive 
generation. During this same period the Holy Inquisition 
selected with extreme care the freest and boldest men in order 
to burn or imprison them. In Spain alone some of the best 
men — those who doubted and questioned, and without doubting 
there can be no progress — were eliminated during three cen- 
turies at the rate of a thousand a year. The evil which the 
Catholic Church has thus effected is incalculable, though no 
doubt counterbalanced to a certain, perhaps to a large, extent 
in other ways; nevertheless, Europe has progressed at an un- 
paralleled rate. 

2® See the ingenious and original 257) advances arguments on the 

argument on this subject by Mr. othi'r side. Sir C. Lyell had already 

Galton, 'Hereditary Genius,' i)p. ('Principles of Geology,' vol. .1. 

340-342. 1868, p. 489) in a striking passage 

^^ Mr. Greg, 'Eraser's Magazine,' called attention to the evil inHucnce 

Sept. 1868, p. 357. of the Holy Inquisition in having, 

^® 'Hereditary Genius,' 1870, pp. through selection, lowered the gene- 

357-359. The Rev. F. W. Farrar ral standard of intelligence in Eu- 

(' Fraser's Mag.,' Aug. 1870, p. rope. 

142 The Descent of Alan. Pabt I. 

The remarkable success of the English as colonists, compared 
to other European nations, has been ascribed to their " daring 
" and persistent energy ; " a result which is xvell illustrated by 
comparing the progress of the Canadians of English and French 
extraction ; but who can say how the EngUsh gained their energy ? 
There is apparently much truth in the belief that the wonderful 
progress of the United States, as well as the character of the 
people, are the results of natural selection ; for the more ener- 
getic, restless, and courageous men from all parts of Europe 
have emigrated during the last ten or twelve generations to that 
great country, and have there succeeded best.-^ Looking to the 
distant future, I do not think that the Eev. Mr. Zincke takes an 
exaggerated view when he says :^ '' All other series of events — 
" as that which resulted in the cultui'e of mind in Greece, and 
"that which resulted in the emj^ire of Piome— only appear to 
" have purpose and value when viewed in connection with, or 
" rather as subsidiary to ... . the gi'eat stream of Anglo-Saxon 
" emigration to the west." Obscure as is the problem of the 
advance of civilisation, we can at least see that a nation 
which produced during a lengthened period the greatest 
number of highly intellectual, energetic, brave, patriotic, and 
benevolent men, would generally prevail over less favoured 

Natural selection follows from the struggle for existence ; and 
this from a rajDid rate of increase. It is impossible not to regret 
bitterly, but whether wisely is another question, the rate at 
which man tends to increase ; for this leads in barbarous tribes 
to infanticide and many other evils, and in civilised nations to 
abject poverty, celibacy, and to the late marriages of the prudent. 
But as man suffei-e from the same physical evils as the lower 
animals, he has no right to expect an immunity from the evils 
consequent on the struggle for existence. Had he not been sub- 
jected during primeval times to natural selection, assuredly he 
would never have attained to his present rank. Since we see in 
many parts of the world enormous areas of the most fertile land 
capable of supporting numerous happy homes, but peopled only 
by a few wandering savages, it might be argued that the struggle 
for existence had not been sufficiently severe to force man up- 
wards to his highest standard. Judging from all that we know 
of man and the lower animals, there has always been sufficient 
variability in their intellectual and moral faculties, for a steady 
advance through natural selection. No doubt such advance 

29 Mr. Gallon, ' Macmillau's and National Life,' Dec. 1869, p. 184. 
Magazine,' August, 1865, p. 32 o. ^o ^Last Winter in the United 

See also, 'Nature,' 'On Darwinism States,' 1868, p. 29. 

Chap. V. Civilised Nations. 143 

demands many favourable concurrent circumstances ; but it may 
well be doubted whether the most favourable would have sufficed, 
had not the rate of increase been rapid, and the consequent 
struggle for existence extremely severe. It even appears from 
what we see, for instance, in parts of S. America, that a people 
which may be called civilised, such as the Spanish settlers, is 
liable to become indolent and to retrograde, when the con- 
ditions of life are very easy. With highly civilised nations con- 
tinued progress depends in a subordinate degree on natural 
selection-; for such nations do not supplant and exterminate one 
another as do savage tribes. Nevertheless the more intelligent 
members within the same community will succeed better in the 
long run than the inferior, and leave a more numerous progeny, 
and this is a form of natural selection. The more efficient 
causes of progress seem to consist of a good education during 
youth whilst the brain is impressible, and of a high standard of 
excellence, inculcated by the ablest and best men, embodied in 
the laws, customs and traditions of the nation, and enforced by 
public opinion. It should, however, be borne in mind, that the 
enforcement of public opinion depends on our appreciation of 
the approbation and disapprobation of others ; and this apprecia- 
tion is founded on our sympathy, which it can hardly be doubted 
was originally developed through natural selection as one of the 
most important elements of the social instincts.^^ 

On the evidence that all civUked nations ivere once harlarotis. — 
The present subject has been treated in so full and admirable a 
manner by Sir J. Lubbock,"^ Mr. Tylor, Mr. M'Lenuan, and 
others, that I need here give only the briefest summary of their 
results. The arguments recently advanced by the Duke of 
ArgylP^ and formerly by Archbishop Whately, in favour of the 
belief that man came into the world as a civilised being, and 
that all savages have since undergone degradation, seem to me 
weak in comparison with those advanced on the other side. 
Many nations, no doubt, have fallen away in civilisation, and 
some may have lapsed into utter barbarism, though on this 
latter head I have met with no evidence. The Fuegians were 
probably compelled by other conquering hordes to settle in their 
inhospitable country, and they may have become in consequence 
somewhat more degraded; but it would be difficult to prove 

" I am much iudebted to Mr. '^ 'On the Origin of Civilisation," 

John Morley for some good criti- * Proc. Ethnological Soc' Nov. 26 

cisms on this subject: see, also, 1867. 

Broca, 'Les Selections,' 'Kevue d'Au- ^■^ ' Primeval Man,' 18G9. 
thropologie,' 1872. 

144 ^^^^ Descent of Man. Part I. 

that they have fallen much below the Botocudos, who inhabit 
the finest parts of Brazil. 

The evidence that all civilised nations are the descendants of 
barbarians, consists, on the one side, of clear traces of their 
former low condition in still-existing customs, beliefs, language, 
&c.; and on the other side, of proofs that savages are inde- 
pendently able to raise themselves a few steps in the scale of 
civilisation, and have actually thus risen. The evidence on the 
first head is extremely curious, but cannot be here given : I refer 
to such cases as that of the art of enumeration, which, as Mr. 
Tylor clearly shews by reference to the words still used in some 
places, originated in counting the fingers, first of one hand and 
then of the other, and lastly of the toes. We have traces of this 
in our own decimal system, and in the Eoman numerals, where, 
after the V., which is supposed to be an abbreviated picture of a 
human hand, we pass on to VI., &c., when the other hand no 
doubt was used. So again, " when we speak of three-score and 
" ten, we are counting by the vigesimal system, each score thus 
" ideally made, standing for 20— for ' one man ' as a Mexican or 
" Carib would put it."^^ According to a large and increasing 
school of philologists, every language bears the marks of its slow 
and gradual evolution. So it is with the art of writing, for 
letters are rudiments of pictorial representations. It is hardly 
possible to read Mr. M'Lennan's work^^ and not admit that 
almost all civilised nations still retain traces of such rude habits 
as the forcible capture of wives. What ancient nation, as the 
same author asks, can be named that was originally mono- 
gamous ? The primitive idea of justice, as shewn by the law of 
battle and other customs of which vestiges still remain, was 
likewise most rude. Many existing superstitions are the 
remnants of former false religious beliefs. The highest form of 
religion — the gi-and idea of God hating sin and loving right- 
eousness — was unknown during primeval times. • . 

Turning to the other kind of evidence : Sir J. Lubbock has 
shewn that some savages have recently improved a little in 
some of their simpler arts. From the extremely curious 
account which he gives of the weapons, tools, and arts, in use 

3* ' Royal Institution of Great ' A Conjectural Solution of the 
Britain,' March 15, 1867. Also, Origin of the Class, System of 
' Researches into the Early History Relationship,' in ' Proc. American 
of Mankind,' 1865. Acad, of Sciences,' vol. vii. Feb. 

35 'Primitive Marriage,' 1865. 1868. Prof. Schaaffhausen ('An- 
See, likewise, an excellent article, thropolog. Review,' Oct. 1869, p. 
evidently by the same author, in 373) remarks on " the vestiges of 
the 'North British Review,' July, "human sacrifices found both in 
1869. Also, Mr, L. H. Morgjin, " Homer and the Old Testament." 

CiiAr. V. Nations. 1 45 

amongst savages in yarious parts of the world, it cannot be 
doubted that these have nearly all been independent discoveries, 
excepting perhaps the art of making fire.^'^ The Australian 
boomerang is a good instance of one such independent discovery. 
The Tahitians when first visited had advanced in many respects 
beyond the inhabitants of most of the other Polynesian islands. 
There are no just grounds for the belief that the high culture of 
the native Peruvians and Mexicans was derived from abroad ; ^^ 
many native plants were there cultivated, and a few native 
animals domesticated. We should bear in mind that, judging 
from the small influence of most missionaries, a wandering crew 
from some semi-civilised land, if washed to the shores of 
America, would not have produced any marked eifect on the 
natives, unless they had already become somewhat advanced. 
Looking to a very remote period in the history of the world, we 
find, to use Sir J. Lubbock's well-known terms, a paleolithic and 
neolithic period; and no one will pretend that the art of 
grinding rough flint tools was a borrowed one. In all parts of 
EurojDe, as far east as Greece, in Palestine, India, Japan, New 
Zealand, and Africa, including Egypt, flint tools have been 
discovered in abundance; and of their use the existing in- 
habitants retain no tradition. There is also indirect evidence of 
their former use by the Chinese and ancient Jews. Hence there 
can hardly be a doubt that the inhabitants of these countries, 
which include nearly the whole civilised world, were once 
in a barbarous condition. To believe that man was abori- 
ginally civilised and then suffered utter degradation in so many 
regions, is to take a pitiably low view of human nature. It is 
apparently a truer and more cheerful view that progress 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 reUgion. 

3« Sir J. Lubbock, 'Prehistoric edit., 1870. 

Times,' 2ad edit. 1869, chap. xv. ^r j^j.. F. Miiller has made some 

and xvi. et passim. See also the good remarks to this effect in the 

excellent 9th chapter in Trior's ' Reise der Novara : Anthropolog. 

Early History of Mankind,'' 2nd Theil,' Abtheil. iii. 18G8, s. 127. 

146 The Descent of Maiu Pakt I. 

On the Affinities and Genealogy cf Man. 

Position of man in the animal series — The natui'al system genealogical — ■ 
Adaptive characters of slight value — Various small points of resem- 
blance between man and the Quadrumana — Rank of man in the natural 
system — Birthplace and antiquity of man — Absence of fossil connecting- 
links — Lower stages in the genealogy of man, as inferred, firstly from 
his affinities and secondly from his structure — Early androgynous con- 
dition of the Vertebrata — Conclusion. 

Even if it be granted that the diflference between man and his 
nearest allies is as great in cori)oreal structure as some natu- 
ralists maintain, and although we must grant that the differ- 
ence between them is immense in mental power, yet the facts 
given in the earlier chapters appear to declare, in the plainest 
manner, that man is descended from some lower form, notwith- 
standing that connecting-links have not hitherto been dis- 

Man is liable to numerous, slight, and diversified variations, 
which are induced by the same general causes, are governed 
and transmitted in accordance with the same general laws, as in 
the lower animals. Man has multiplied so rapidly, that ho has 
necessarily been exposed to struggle for. existence, and con- 
sequently to natural selection. He has given rise to many races^ 
some of which differ so much from each other, that they have 
often been ranked by naturalists as distinct species. His body 
is constructed on the same homological jDlan as that of other 
mammals. He passes thi'ough the same phases of embryo- 
logical development. He retains many rudimentary and useless 
structures, which no doubt were once serviceable. Characters 
occasionally make their re-appearance in him, which we have 
reason to believe were possessed by his early progenitors. If the 
origin of man had been wholly different from that of all other 
animals, these various appearances would be mere empty 
deceptions ; but such an admission is incredible. These appear- 
ances, on the other hand, are intelligible, at least to a large 
extent, if man is the co-descendant with other mammals of some 
unkno\\Ti and lower form. 

Some natm-alists, from being deeply impressed with the 
mental and spiritual powers of man, have divided the whole 
organic world into three kingdoms, the Human, the Animal, 

CiiAi'. VI. Affinities and Genealogy. 147 

and the Vegetable, thus giving to man a separate kingdom.' 
Spiritual powers cannot be compared or classed by the natu- 
ralist: but he may endeavour to shew, as I have done, that the 
mental faculties of man and the lower animals do not differ in 
kind, although immensely in degree. A difference in degree, 
however great, does not justify us in placing man in a distinct 
kingdom, as will perhaps be best illustrated by comparing the 
mental j^owers of two insects, namely, a coccus or scale-insect 
and an ant, which undoubtedly belong to the same class. The 
difference is here greater than, though of a somewhat different kind 
from, that between man and the highest mammal. The female 
coccus, whilst young, attaches itself by its proboscis to a plant ; 
sucks the sap, but never moves again ; is fertilised and lays eggs ; 
and this is its whole history. On the other hand, to describe the 
habits and mental powers of worker-ants, would require, as 
Pierre Huber has shewn, a large volume ; I may, however, briefly 
specify a few points. Ants certainly communicate information to 
each other, and several unite for the same work, or for games of 
play. They recognise their fellow-ants after months of absence, 
and feel sympathy for each other. They build gi'eat edifices, 
keep them clean, close the doors in the evening, and post 
sentries. They make roads as well as tunnels under rivers, and 
temporary bridges over them, by clinging together. They 
collect food for the community, and when an object, too large for 
entrance, is brought to the nest, they enlarge the door, and 
afterwards build it up again. They store up seeds, of which 
they prevent the germination, and which, if damp, are brought 
up to the surface to dry. They keep aphides and other insects as 
milch-cows. They go out to battle in regular bands, and freely 
sacrifice their lives for the common weal. They emigrate ac- 
cording to a preconcerted plan. They capture slaves. They move 
the eggs of their aphides, as well as their own eggs and cocoons, 
into warm parts of the nest, in order that they may be quickly 
hatched ; and endless similar facts could be given.^ 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. IS'o 

* Isidore GeofFroy St.-Hilaire gives of auts are given by Mr. Belt, in 

a detailed account of the position in his 'Naturalist in Kicaragua,' 

assigned to man by various natural- 1874. See also Mr. Sloggridge's 

ists in their classifications: 'Hist, admirable work, ' Harvesting Ants,' 

Nat. Gen,' torn. ii. 1859, pp. 170- &e., 1873, also ' L'Instinct chez les 

189. Insectes,' by M. George Pouchet, 

- Some of the most interesting 'Revue des Deux Moudes,' Feb. 

facts ever published on the habits 1870 p. 682. 

148 The Descent of Man. Part T. 

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 foi-ms having become extinct. 

Professor Owen, relying chiefly on the structure of the brain, 
has divided the mammalian series into four sub-classes. One of 
these he devotes to man; in another he places both the 
Marsupials and the Monotremata; so that he makes man as 
distinct from all other mammals as are these two latter groups 
conjoined. This view has not been accepted, as far as I am 
aware, by any naturalist capable of forming an independent 
judgment; and therefore need not here be further considered. 

We can understand why a classification founded on any single 
character or organ— even an organ so wonderfully complex and 
important as the brain — or on the high development of the 
mental faculties, is almost sure to prove unsatisfactory. This 
principle has indeed been tried with hymenopterous insects; 
but when thus classed by their habits or instincts, the arrange- 
ment proved thoroughly artificial.^ Classifications may, of 
course, be based on any character whatever, as on size, colour, 
or the element inhabited; but naturalists have long felt a 
profound conviction that there is a natural system. This 
system, it is now generally admitted, must be, as far as possible, 
genealogical in arrangement, — that is the co-descendants of the 
same form must be kept together in one group, apart from the 
co-descendants of any other form ; but if the parent-forms are 
related, so will be their descendants, and the two groups to- 
gether will form a larger group. The amount of difference 
between the several groups — that is the amount of modification 
which each has undergone— is expressed by such terms as 
genera, families, orders, and classes. As we have no record of 
the lines of descent, the pedigree can be discovered only by 
observing the degrees of resemblance between the beings which 
are to be classed. For this object numerous points of resem- 
blance are of much more importance than the amount of 
similarity or dissimilarity in a few points. If two languages 
were found to resemble each other in a multitude of words and 
points of construction, they would be universally recognised as 
having sprung from a common source, notwithstanding that 
they differed greatly in some few words or points of construction. 
But with organic beings the points of resemblance must not 
consist of adaptations to similar habits of fife : two animals may, 
for instance, have had their whole frames modified for living in 

' Westwood, ' Modern Class of Insects/ vol. ii. 1840, p. 87. 

Chap. XL Affinities and Genealogy. 149 

the ■water, and yet they will not be bronglit any nearer to each 
other in the natural system. Hence "sve can see how it is that 
resemblances in several unimportant structures, in useless and 
rudimentary organs, or not now functionally active, or in an 
embryological condition, are by far the most serviceable for clas- 
sification ; for they can hardly be due to adaptations within a 
late period ; and thus they reveal the old lines of descent or of 
true affinity. 

We can further see why a gi-eat amount of modification in 
some one character ought not to lead us to separate widely any 
two organisms. A part which already differs much from the 
same part in other allied forms has already, according to the 
theory of evolution, varied much ; consequently it would (as long 
as the organism remained exposed to the same exciting con- 
ditions) be liable to further variations of the same kind ; and 
these, if beneficial, would be preserved, and thus be continually 
augmented. In many cases the continued development of a part, 
for instance, of the beak of a bird, or of the teetli of a mammal, 
would not aid the species in gaining its food, or for any other 
object ; but with man we can see no definite limit to the con- 
tinued development of the brain and mental faculties, as far as 
advantage is concerned. Therefore in determining the position 
of man in the natural or genealogical system, the extreme de- 
velopment of his brain ought not to outweigh a multitude of 
resemblances in other less important or quite unimportant 

The greater number of naturalists who have taken into con- 
sideration the whole structure of man, including his mental 
faculties, have followed Blumenbach and Cuvier, and have placed 
man in a separate Order, under the title of the Bimana, and 
therefore on an equality with the orders of the Quadrumana, 
Carnivora, &c. Recently many of our best naturalists have 
recurred to the view first propounded by Linnscus, so remarkable 
for his sagacity, and have placed man in the same Order with 
the Quadrumana, under the title of the Primates. The justice of 
this conclusion will be admitted : for in the first place, we must 
bear in mind the comparative insignificance for classification 
of the great development of the brain in man, and that the 
strongly-marked differences between the skulls of man and tlK^ 
Quadrumana (lately insisted upon by Bischoff, Aeby, and others) 
apparently follow from their differently developed brains. In 
the second place, we must remember that nearly all the other 
and more important difi'crences Ixitween man and the Quadrumana 
are manifestly adaptive in their nature, and relate cliiefly to tljo 
erect position of man ; such as the structure of his hand, /oot, 

1 50 The Descent of Man. Part I. 

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 Carnivora in the form of their 
bodies and in the structure of their limbs, far more ihan does 
man from the higher apes ; yet in most systems, from ihat 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 classifier, he would never have thought of founding 
a separate order for his own reception. < 

It would be beyond my limits, and quite beyond my knowledge, 
even to name the innumerable points of structure in which man 
agrees with the other Primates. Our great anatomist and 
l^hilosopher. Prof. Huxley, has fully discussed this subject,^ and 
concludes that man in all parts of his organisation differs less 
from the higher apes, than these do from the lower members of 
the same group. Consequently there "is no justification for 
" placing man in a distinct order." 

In an early part of this work I brought forward various 
facts, shewing how closely man agrees in constitution with the 
higher mammals ; and this agreement must depend on our 
close similarity in minute structure and chemical composition. 
I gave, as instances, our liability to the same diseases, and to the 
attacks of allied parasites ; our tastes in common for the same 
stimulants, and the similar effects produced by them, as well as 
by various drugs, and other such facts. 

As small unimportant points of resemblance between man and 
the Quadrumana are not commonly noticed in systematic works, 
and as, when numerous, they clearly reveal our relationship, I 
will specify a few such points. The relative position of our 
features is manifestly the same ; and the various emotions are 
displayed by nearly similar movements of the muscles and skin, 
chiefly above the eyebrows and round the mouth. Some few 
expressions are, indeed, almost the same, as in the weeping of 
certain kinds of monkeys and in the laughing noise made by 
others, during which the corners of the mouth are drawn back- 
wards, and the lower eyelids wrinkled. The external ears are 
curiously alike. In man the nose is much more prominent than 
in most monkeys ; but we may trace the commencement of an 
aquiline curvature in the nose of the Hoolock Gibbon ; and this 
in the Semnopitliecus nasica is carried to a ridiculous extreme. 

The faces of many monkeys are ornamented with beards, 
whiskers, or moustaches. The hair on the head grows to a great 
"» 'Pvoc. Zoolog. Soc' 1863, p. 4. 

. * ' Evidence as to Man's Piace in Nature,' 1863, p. 70, et passim. 

CH4P. vr. Affinities and Genealogy. 151 

length in some species of Scmnopithccus ;'' and in the Bonnet 
monkey (Macacus radiatus) it radiates from a point on the crown, 
with a parting down the middle. It is commonly said that the 
forehead gives to man his noble and intellectual appearance ; but 
the thick hair on the head of the Bonnet monkey terminates 
downwards abruptly, and is succeeded by hair so short and fine 
that at a little distance the forehead, with the exception of the 
eyebrows, appears quite naked. It has been erroneously asserted 
that eyebrows are not present in any monkey. In the species 
just named the degree of nakedness of the forehead differs in 
different individuals ; and Eschricht states ^ 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 yjrogenitor, in whom the forehead 
had not as yet become quite naked. 

It is well known that the hair on our arms tends to converge 
from above and below to a point at the elbow. Tliis 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 
IJylohates agilis the hair on the fore-arm is directed downwards 
or towards the wrist in the ordinary manner ; and in //. 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 transverse hairs on the fore- legs of a dog may serve for this 
end when he is coiled up asleep. Mr. Wallace, who has carefully 
studied the habits of the orang, remarks that the convergence of 
the hair towards the elbow on the arms of the orang may be 
explained as serving to throw off the rain, for this animal during 
rainy weather sits with its arms bent, and with the hands clasped 
round a branch or over its head. According to Livingstone, the 
gorilla also " sits in pelting rain with his hands over his head."" 
If the above explanation is correct, as seems probable, the direc- 
tion of the hair on our own arms offers a curious record of our 
former state ; for no one supposes that it is now of any use in 
throwing off the rain ; nor, in our jDresent erect condition, is it 
properly directed for this purpose. 

It would, however, be rash to trust too much to the principle 
of adaptation in regard to the direction of the hair in man or his 

« Isid. GeoflFroy, ' Hist. Xiit. Gen.' Anat. und Phys.' 1837, s. 51. 

torn. ii. 1859, p. 217. " Quoted by Reade, 'The African 

^ ' Ueber die ILichtung der Sketch Book, ''vol. i., 1873, p. 152. 
Haare,' kc, Muller's 'Archiv I'iir 

152 The Descent of Man. ' Paut I. 

early iDrogenitors ; for it is impossible to study the figures given 
by Escbricht of the arrangement of the hair on the human foetus 
(this being the same as in the adult) and not agree with this 
excellent observer that other and more complex causes have 
intervened. The points of convergence seem to stand in some 
relation to those points in the embryo which are last closed in 
duiing development. There appears, also, to exist some relation 
between the arrangement of the hair on the limbs, and the course 
of the medullary arteries.^ 

It must not be supposed that the resemblances between man 
and certain apes in the above and many other points — such as in 
having a naked forehead, long tresses on the head, &c. — are all 
necessarily the result of unbroken inheritance from a common 
progenitor, or of subsequent reversion. Many of these resem- 
blances are more probably due to analogous variation, which 
follows, as I have elsewhere attempted to shew,^" from co-descended 
organisms having a similar constitution, and having been acted on 
by like causes inducing similar modifications. "With respect to 
the similar direction of the hair on the fore-arms of man and 
certain monkeys, as this character is common to almost all the 
anthropomorphous apes, it may probably be attributed to in- 
heritance; but this is not certain, as some very distinct American 
monkeys are thus characterised. 

Although, as we have now seen, man has no just right to form 
a separate Order for his own reception, he may perhaps claim a 
distinct Sub-order or Family. Prof. Huxley, in his last work," 
divides the Primates into three Sub-orders; namely, the An- 
thropidse with man alone, the Simiadae including monkeys of all 
kinds, and the Lemuridse with the diversified genera of lemurs. 
As far as differences in certain important points of structure are 
concerned, man may no doubt rightly claim the rank of a Sub- 
order ; and this rank is too low, if we look chiefly to his mental 
faculties. Nevertheless, from a genealogical point of view it 
appears that this rank is too high, and that man ought to form 
merely a Family, or possibly even only a Sub-family. If we 
imagine three lines of descent proceeding from a common stock, 
it is quite conceivable that two of them might after the lapse of 

^ On the hair iu Hylobates, see the Theory of Natural Selection,' 

'Nat. Hist, of Mammals,' by C. L. 1870, p. 344. 

JMartin, 1841, p. 415. Also, l^iJ. ^^ 'Origin of Species,' 5th edit. 

Geoffroy on the American monkeys 1869, p. 194. 'The Variation of 

and other kinds, ' Hist. Xat. Gen.' Animals and Plants under Domesti- 

vol. ii. 1859, p. 216, 243. Esch- cation,' vol. ii. 1868, p. 348. 
richt, ibiil. s. 46, 55, 61. Owen, ^^ ' An Introduction to the Classi- 

' Aunt, of Vertebrates,' vol. iii. p. fication of Animals,' 1869, p. 99. 
619. Wallace, 'Contributions to 

Chap. Y I. Affinities and Genealogy. 153 

ages be so slightly changed as still to remain as species of the 
same genus, whilst the third line might become so greatly 
modified as to deserve to rank as a distinct Sub- family, Family, 
or even Order. But in this case it is almost certain that the 
third line would still retain through inheritance numerous small 
points of resemblance with the other two. Here, then, would 
occur the difficulty, at present insoluble, how much weight we 
ought to assign in our classifications to strongly-marked dif- 
ferences in some few points, — that is, to the amount of modifi- 
cation undergone ; and how much to close resemblance in 
numerous unimportant points, as indicating the lines of descent 
or genealogy. To attach much weight to the few but strong 
differences is the most obvious and perhaps the safest course, 
though it appears more correct to pay great attention to the 
many small resemblances, as giving a truly natural classification. 

In forming a judgment on this head with reference to man, we 
must glance at the classification of the Simiadae. This family is 
divided by almost all naturalists into the Catarhine group, or 
Old World monkeys, all of which are characterised (as their 
name exjDresses) by the peculiar structure of their nostrils, and by 
having four premolars in each jaw; and into the Platyrhine 
group or New World monkeys (including two very distinct 
sub-groups), all of which are characterised by differently 
constructed nostrils, and by having six j^remolars in each jaw. 
Some other small differences might be mentioned. Now man 
unquestionably belongs in his dentition, in the structure of his 
nostrils, and some other respects, to the Catarhine or Old World 
division ; nor does he resemble the Platyrhines more closely than 
the Catarhines in any characters, excepting in a few of not much 
importance and apparently of an adaptive nature. It is therefore 
against all probability that some New World species should have 
formerly varied and produced a man-like creature, with all the 
distinctive characters proper to the Old World division ; losing 
at the same time all its own distinctive characters. There can, 
consequently, hardly be a doubt that man is an off-shoot from the 
Old World Simian stem ; and that under a genealogical point of 
view, he must be classed with the Catarhine division.^^ 

The anthropomorphous apes, namely the gorilla, chimpanzee, 

^2 This is nearly the same classifi- adse which answer to the Catarhines, 

cation as that provisionally adopted the Cebidae, and the Ilapalida?, — 

by ]Mr. St. George Mivart (' Tran- these two latter groups answering 

sact. Philosoph. Soc' 1867, p. 300), to the Platyrhines. Mr. Mivart 

who, after separating the Lemuridffi, still abides by the same view; see 

divides the remainder of the Pri- ' Nature,' 1871, p. 481. 
mates into the Hominidac, the Simi- 


154 The Descent of Man. Part I. 

orang, and hylobates, are by most naturalists separated from the 
other Old ^Yorld monkeys, as a distinct sub-group. I am aware 
that Gratiolet, relying on the structure of the brain, does not 
admit the existence of this sub-group, and no doubt it is a broken 
one. Thus the orang, as l\Ir. 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 divided by some naturalists into two or three smaller sub- 
groups ; the genus Semnopithecus, with its pecuhar sacculated 
stomach, being the type of one such sub-group. But it appears 
from M. Gaudry's wonderful discoYeries 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 grouj^s were once blended 

If the anthropomorphous apes be admitted to form a natural 
sul>group, then as man agrees with them, not only in all those 
characters which he possesses in common with the whole 
Catarhine groui^, but in other peculiar characters, such as the 
absence of a tail and of callosities, and in general appearance, we 
may infer that some ancient member of the anthropomorphous 
sub-group gave birth to man. It is not probable that, through 
the law of analogous yariation, a member of one of the other 
lower sub-groups should have given rise to a man-like creature, 
resembling the higher anthropomorphous apes in so many 
respects. No doubt man, in comparison with most of his allies, 
has undergone an extraordinary amount of modification, chiefly 
in consequence of the great development of his brain and his 
erect position ; nevertheless, we should bear in mind that he " is 
" but one of several exceptional forms of Primates." ^^ 
- Every naturalist, who believes in the principle of evolution, 
will grant that the two main divisions of the Simiadte, namely 
the Catarhine and Platyrhine monkeys, with their sub-groups, 
have all proceeded from some one extremely ancient progenitor. 
The early descendants of this progenitor, before they had 
diverged to any considerable extent from each other, would still 
have formed a single natural group ; but some of the species or 
inci]oient genera would have already begun to indicate by their 
diverging characters the future distinctive marks of the Catarhine 
and Platyrhine divisions. Hence the members of this supposed 
ancient group would not have been so uniform in their den- 
tition, or in the structure of their nostrils, as are the existing 

13 ' Transact, Zoolog. Soc' vol. vi. ^^ Mr. St. G. Mivart, ' Transact. 

IS67, p. 2U. Phil. Soc' 1867, p. 410. 

Chap. VI. Affinities and Genealogy. 155 

Catarhine monkeys in one way and the Platyrhinos in another 
way, but would have resembled in this respect the allied Lemu- 
ridx, which differ greatly from each other in the form of their 
muzzles/^ and to an extraordinary degree in their dentition. 

The Catarhine and Platyrhine monkeys agree in a multitude 
of characters, as is shewn by their unquestionably belonging 
to one and the same Order. The many characters which 
they possess in common can hardly have been independently 
acquired by so many distinct species ; so that these characters 
must have been inherited. But a naturalist would undoubtedly 
have ranked, as an ape or a monkey, an ancient form which 
possessed many characters common to the Catarhine and 
Platyrhine monkeys, other characters in an intermediate con- 
dition, and some few, perhaps, distinct from those now found in 
either group. And as man from a genealogical point of view 
belongs to the Catarhine or Old World stock, we must conclude, 
however much the conclusion may revolt our pride, that our 
early progenitors would have been properly thus designated.'" 
But we must not fall into the error of supposing that the early 
progenitor of the whole Simian stock, including man, was iden- 
tical with, or even closely resembled, any existing ape or monkey. 

0)1 the Dirthi.lace and Antiquify of Man. — We are naturally 
led to enquire, where was the birthplace of man at that stage of 
descent when our progenitors diverged from the Catarhine 
stock ? The fact that they belonged to this stock clearly shews 
that they inhabited the Old World ; but not Australia nor any 
oceanic island, as we may infer from the laws of geographical 
distribution. In each great region of the world the living 
mammals are closely related to the extinct sjDecies of the same 
region. It is therefore probable that Africa was formerly in- 
habited by extinct apes closely allied to the gorilla and chim- 
panzee ; and as these two species are now man's nearest allies, it 
is somewhat more probable that our early progenitors lived on 
the African continent than elsewhere. But it is useless to 
speculate on this subject; for two or three anthropomorphous 
apes, one the Dryopithccus ^^ of Lartet, nearly as large as a man, 

•^ Messrs. ]\Iurie and Mivart on his ' Natiirliche S-hopfungsge- 

the Lemuroidea, 'Transact. Zoolui;. schichte,' 18G8, iu which he gives 

Sue' vol. vii. 18G9, p. 5. iu detail his views on the genealogy 

'^ Hilckel has come to this same of man. 

conclusion. See ' Ueber die Ent- " Dr. C. Forsyth Major, ' Sur les 

stehung des Menschengeschlechts,' Singes Fossiles trouves en Italie :* 

in Virchow's ' Sammlung. gemein. ' Soc.Ital. des Sc. Nat.' torn. xv. 1872. 
wissen. Vortriige,' 18G8, s. Gl. Also 

156 The Descent of Man. Part 1. 

and closely allied to Hylobates, existed in Europe during the 
Miocene age ; and since so remote a period the earth has 
certainly undergone many great revolutions, and there has been 
ample time for migration on the largest scale. 

At the period and place, wheneyer and whereTer it was, when 
man first lost his hairy coYering, he probably inhabited a hot 
country ; a circumstance favourable for the frugiferous diet on 
wliich, judging from analogy, he subsisted. We are far from 
knowing how long ago it was when man first diverged from the 
Catarhine stock; but it may have occurred at an epoch as remote 
as the Eocene period; for that the higher apes had diverged 
from the lower apes as early as the Upper Miocene period is 
shewn by the existence of the Dryopithecus. We are also quite 
ignorant at how rajDid a rate organisms, whether high or low in 
the scale, may be modified under favourable circumstances ; we 
know, however, that some have retained the same form during 
an enormous lapse of time. From what we see going on under 
domestication, 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 extinct or 
living species, has often been advanced as a grave objection to 
the belief that man is descended from some lower form ; but this 
objection will not appear of much weight to those who, from 
general reasons, believe in the general princij)le 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 — betw^een the Tarsius and the 
other Lemuridse — between the elephant, and in a more striking 
manner between the Ornithorhynchus or Echidna, and a.l other 
mammals. But these breaks depend merely on the number of 
related forms which have become extinct. At some future 
period, not very distant as measured by centuries, the civilised 
races of man will almost certainly exterminate, and replace, the 
savage races throughout the world. ^ At the same time the anthro- 
pomorphous apes, as Professor Schaafifliausen has remarked,^^ 
will no doubt be exterminated. The break between man and his 
nearest allies will then be wider, for it will intervene between 
man in a more civilised state, as we may hope, even than the 
Caucasian, and some ai)e as low as a baboon, instead of as no «v 
between the negro or Australian and the gorilla. 

" ' Anthropological Review/ April, 1867, p. 236. 

Chap. YI. Affinities and Genealogy. 1 57 

"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. Ly ell's discussion,'^ where 
he shews that in all the vertebrate classes the discovery of fossil 
remains has been a very slow and fortuitous process. Nor 
should it be forgotten that those regions which are the most 
hkely 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 Catarhine or Old World 
division of the Simiadae, after these had diverged from the New 
World division. We will now endeavour to follow the remote 
traces of his genealogy, trusting principally to the mutual 
affinities between the various classes and orders, with some 
slight reference to the periods, as far as ascertained, of their 
successive appearance on the earth. The Lemuridae stand 
below and near to the Simiadse, and constitute a very distinct 
family of the Primates, or, according to Hackel and others, a 
distinct Order. This group is diversified and broken to an 
extraordinary degree, and includes many aberrant forms. It 
has, therefore, i:)robably suffered much extinction. Most of the 
remnants survive on islands, such as Madagascar and the 
Malayan archipelago, where they have not been exposed to so 
severe a competition as they would have been on well-stocked 
continents. This group likewise presents many gradations, 
leading, as Huxley remarks,-*' '' insensibly from the crown and 
" summit of the animal creation down to creatures from which 
" there is but a step, as it seems, to the lowest, smallest, and 
" least intelligent of the placental mammalia." From these 
various considerations it is probable that the Simiadai were 
originally developed from the progenitors of the existing 
Lemnridaj ; and these in their turn from forms standing very 
low in the mammalian series. 

The Marsupials stand in many important characters below the 
placental mammals. They appeared at an earlier geological 
period, and their range was formerly much more extensive 
than at present. Hence the Placentata are generally supposed 
to have been derived from the Implacentata or Marsui)ials; 
not, however, from forms closely resembling the existing Mar- 
supials, l)ut from their early progenitors. The Monotremata are 
plainly allied to the Marsupials, forming a third and still lower 

'» 'Elements of Geology,' 1865, 20 < Man's Place in Nature,' p. 

pp. 583-585. ' Antiquity of Man,' 105. 
1863, p. 145. 

158 The Descent of Man, Paut I 

division in tlie great mammalian series. They are represented 
at the present day solely by the Ornithorhynchus and Echidna ; 
and these two fonns may be safely considered as relics of a 
much larger group, representatives of which have been preserved 
in Australia through ^ome favourable concurrence of circum- 
stances. The Monotremata are eminently interesting, as leading 
in several important points of structure towards the class of 

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. Hackel's works.^^ I will content myself with 
a few general remarks. Every evolutionist will admit that the 
five great vertebrate classes, namely, mammals, birds, reptiles, 
amphibians, and fishes, are descended from some one prototype ; 
for they have much in common, especially during their embryonic 
state. As the class of fishes is the most lowly organised, and 
appeared before the others, we may conclude that all the 
members of the vertebrate kingdom are derived from some fish- 
like animal. The belief that animals so distinct as a monkey, 
an elephant, a humming-bird, a snake, a frog, and a fish, &c., could 
all have sprung from the same parents, will appear monstrous 
to those who have not attended to the recent progress of natural 
history. For this belief implies the former existence of links 
binding closely together all these forms, now so utterly unlike. 

Nevertheless, it is certain that groups of animals have existed, 
or do now exist, which serve to connect several of the great 
vertebrate classes more or less closely. We have seen that the 
Ornithorhynchus graduates towards reptiles ; and Prof. Huxley 
has discovered, and is confirmed by Mr. Cope and others, that 
the Dinosaurians are in many important characters intermediate 
between certain reptiles and certain birds— the birds referred 
to being the ostrich- tribe (itself evidently a widely-diffused 
remnant of a larger group) and the Archeopteryx, that strange 
Secondary bird, with a long lizard-like tail. Again, according to 

21 Elaborate tables are given in the phylum or lines of descent of 

his * Generelle Morphologie ' (B. ii. the Vertebrata to be admirabl}' dis- 

s. cliii. and s. 425) ; and with more cussed by Hackel, although he differs 

especial reference to man in his on some points. He expresses, 

'Natiirliche Schopfuugsgeschichte,' also, his high estimate of the 

1868. Prof. Huxley, in reviewing general tenor and spirit of the 

this latter work ('The Academj-/ whole work. 

18(39, p. 42) says, that he" considers 22 Palaeontology,' 1860, p. 199. 

Chap. VI. Affinities and Genealogy. 159 

Prof. Owen,-2 the Tchthyosanrians— 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 earlier 
geological periods, and were constructed on what is called a 
generalised type, that is, they presented diversified affinities with 
other groups of organisms. The Lepidosiren is also so closely 
allied to amphibians and fishes, that naturalists long disputed in 
which of these two classes to rank it ; it, and also some few 
Ganoid fishes, have been preserved from ntter extinction by 
inhabiting rivers, which are harbours of refuge, and are related 
to the great waters of the ocean in the same way that islands 
are to continents. 

Lastly, one single member of the immense and diversified class 
of fishes, namely, the lancelet or amphioxus, is so different from 
all other fishes, that Hackel maintains that it ought to form a 
distinct class in the vertebrate kingdom. This fish is remarkable 
for its negative characters ; it can hardly be said to possess a 
brain, vertebral column, or heart, &c. ; so that it was classed by 
the older naturalists amongst the worms. Many years ago Prof. 
Goodsir perceived that the lancelet presented some affinities with 
the Ascidians, which are invertebrate, hermaphrodite, marine 
creatures permanently attached to a support. They hardly 
appear like animals, and consist of a simple, tough, leathery 
sack, with two small projecting orifices. They belong to the 
Molluscoida of Huxley— a lower division of the great kingdom 
of the Mollusca ; but they have recently been placed by some 
naturahsts amongst the Vermes or worms. Their larvae some- 
what resemble tadpoles in shape,-^ and have the power of 
swimming freely about. M. Kovalevsky -■* has lately observed that 
the larvae of Ascidians are related to the Vertebrata, in their 
manner of development, in the relative position of the nervous 
system, and in possessing a structure closely like the chorda 
dorsalis of vertebrate animals; and in this he has been since 

-^ At the Falkland Islands I had under a simple microscope, plainly 

tlie satisfaction of seeing, in April divided by transverse opaque parti- 

1833, and therefore some years be- tions, which I presume represent 

tore any other naturalist, the loco- the great cells figured by Kovalev- 

motive larvae of a compound Asci- sky. At an early stage of develop- 

dian, closely allied to Synoicum, raent the tail was closely coiled 

but apparently renerically distinct round the head of the larva, 

from it. The tail was about five ^^ ' Memoiros de I'Acad. des 

times as long as the oblong head, Sciences de St. Pe'tersliourg,' torn. x. 

and terminated in a very fine fila- No. 15, 186G. 
ment. It was, as bketclied by me 

i6o The Descent of Man. Pakt I. 

confirmed by Prof. Kupffer. M. Kovalevsky writes to me from 
Naples, that he has now carried these observations yet further ; 
and should his results be well established, the whole will form a 
discovery of the very greatest value. Thus, if we may rely on 
embryology, ever the safest guide in classification, it seems that 
we have at last gained a clue to the source whence the Yertebrata 
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 larvae of our present Ascidians, 
which diverged into two great branches— the one retrograding in 
development and producing the present class of Ascidians, the 
other rising to the crown and summit of the animal kingdom by 
giving birth to the Yertebrata. 

We have thus far endeavoured rudely to trace the genealogy 
of the Yertebrata by the aid of their mutual aflBnities. We will 
now look to man as he exists ; and we shall, I think, be able 
partially to restore the structure of our early progenitors, during 
successive iDeriods, but not in due order of time. This can be 
eff'ected 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 tlie 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 covered 
with hair, both sexes having beards ; their ears were probably 
pointed, and capable of movement ; and their bodies were pro- 
vided with a tail, having the proper muscles. Their limbs and 
bodies were also acted on by many muscles which now only 
occasionally reappear, but are normally present in the Quadru- 
mana. At this or some earlier period, the great artery and nerve 
of the humerus ran thi'ough a supra-condyloid foramen. The 
intestine gave forth a much larger diverticulum or caecum than 
that now existing. The foot was then prehensile, judging from 
the condition of the great toe in the foetus ; and our progenitors, 
no doubt, were arboreal in their habits, and frequented some 
warm, forest-clad land. The males had great canine teeth, which 

25 But I am bound to add that " peut produire la disposition fonda- 

some competent judges dispute this " mentale du type A-ertebre (I'ex- 

couclusion ; for instance, M. Giard, " istence d'une corde dorsale) chez 

in a series of papers in the 'Archives " un iuvertebre par la seule con- 

dc Zoologie Experimentale,' for 1872. " dition vitale de I'adaptation, 

Nevertheless, this naturalist re- " et cette simple possibilite du 

marks, p. 28i, " L'organisaiion de la "passage supprirae I'abime entre 

" larve ascidienne en dehors de " les deux sous-regnes, encore bien 

" toute hypothfese etde toutethebrie, *' qu'en ignore par oil le passage 

" nous montre comment la nature '• s'est fait en reality." 

Chap. VI. Affinities and Ge7iealogy. i6i 

served them as formidable weapons. At a miicli earlier period 
the uterus was double; the excreta were voided through a cloaca; 
and the eye was protected by a third eyelid or nictitating mem- 
brane. At a still earlier period the progenitors of man must have 
been aquatic in their habits; for morjAology 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 branchiss once existed. In the lunar or weekly re- 
current periods of some of our functions we apparently still retain 
traces of our primordial birthplace, a shore washed by the tides. 
At about this same early period the true kidneys were replaced 
by the corpora wolffiana. The heart existed as a simple pulsating 
vessel; and the chorda dorsalis took the place of a vertebral 
column. These early ancestors of man, thus seen in the dim 
recesses of time, must have been as simply, or even still more 
simply organised than the lancelet or amphioxus. 

There is one other point deserving a fuller notice. It has long 
been known that in the vertebrate kingdom one sex bears 
rudiments of various accessory parts, appertaining to the re- 
productive system, which properly belong to the opposite sex ; 
and it has now been ascertained that at a very early embryonic 
period both sexes possess true male and female glands. Hence 
some remote progenitor of the whole vertebrate kingdom appears 
to have been hermaphrodite or androgynous.^*^ But here we 
encounter a singular difficulty. In the mammalian class the 
males possess rudiments of a uterus with the adjacent passage, 
in their vesiculse prostaticse ; they bear also rudiments of 
mammae, and some male Marsupials have traces of a marsupial 
sack.^^ Other analogous facts could be added. Are we, then, to 
suppose that some extremely ancient mammal continued andro- 
gynous, after it had acquired the chief distinctions of its class, 
and therefore after 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 accessory parts, 

-^ This is the conclusion of Prof. *' brata a]-e, in their early condition. 

Gegenbaur, one of the highest au- " hermaphrodite." Similar views 

thorities in comparative anatomy; have long been held by som« authors, 

sec'Grundziigeder vergleich. Anat.' though until recently without a 

1870, s. 876. The result has been firm basis. 

arrived at chiefly from the study of ^^ The male Thylacinus offers the 

the Amphibia; but it appears from best instance. Owen, 'Anatomy of 

the researches of Waldeyer. (as Vertebrates,' vol. iii. p. 771. 

quoted in 'Journal of Anat. and ^^ Hermaphroditism has been ob- 

Phys.' 1869,^ p. 161), that the sexual served in several species of Serranus, 

oriT-ms of even "the higher verte- as well a^ in some other fishes, 

1 62 The Descent of Man. Pakt I. 

proper to each sex, are found in a rudimentary condition in the 
opposite sex, may he 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 colours, acquired for battle or ornament by male 
birds, and inherited by the females in an imperfect or rudimentary 

The possession by male mammals of functionally imperfect 
mammary organs is, in some respects, especially curious. 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 probable that the progenitors of 
the class also had milk-secreting glands, but no nipples. This 
conclusion is supported by what is known of their manner of 
development ; for Professor Turner informs me, on the authority 
of Kolliker and Langer, that in the embryo the mammary glands 
can be distinctly traced before the nipples are in the least 
visible; and the development of successive parts in the indi- 
vidual generally represents and accords with the development of 
successive beings in the same line of descent. The Marsupials 
differ from the Monotremata by possessing nipples; so that 
probably these organs were first acquired by the Marsupials, 
after they had diverged from, and risen above, the Monotremata, 
and were then transmitted to the placental mammals.^^ No one 
will suppose that the Marsupials still remained androgynous 
after they had approximately acquired their present structure. 
How then are we to account for male mammals possessing 
mammae ? It is possible that they were first developed in the 
females and then transferred to the males ; but from what 
follows this is hardly probable. 

where it is either normal and sym- delle Scienze,' Bologna, Doc. 28, 

metrical, or abnormal and uni- 1871) that eels ai-e androgynous, 

lateral. Dr. Zouteveen has given ^^ Prof. Gegenbaur has shewn 

me references on this subject, more (* Jenaische Zeitschrift,' Bd. vii. p. 

especially to a paper by Prof Hal- 212) that two distinct types of 

bertsma, in the ' Transact, of the nipples prevail throughout the 

Dutch Acad, of Sciences,' vol. xvi. several mammalian orders, but 

Dr. Giinther doubts the fact, but that it is quite intelligible how both 

it has now been recorded by too could have been derived from the 

many good observers to be any nipples of the Marsupials, and the 

longer disputed. Dr. M. Lessona latter from those of the Monotre- 

writes to me, that he has veri- mata. See, also, a memoir by Dr. 

fied the observations made by Max Huss, on the mammary glands, 

Cavolini on Serranus. Prof Ereo- ibid. B. viii. p. 176. 
lani has recently shewn (' Accad. 

Chap. VI. Affinities and Genealogy. 163 

It may be suggested, as another view, that long after the 
progenitors of the whole mammalian class had ceased to be 
androgynous, both sexes yielded milk, and thus nourished their 
young ; and in the case of the Marsupials, that both sexes carried 
their young in marsupial sacks. This will not appear altogether 
improbable, if we reflect that the males of existing syngnathous 
fishes receive the eggs of the females in their abdominal pouches, 
hatch them, and afterwards, as some believe, nourish the 
young ;^ — that certain other male fishes hatch tlie eggs within 
their mouths or branchial cavities ; — that certain male toads 
take the chaplets of eggs from the females, and wind them round 
their own thighs, keeping them there until the tad])oles are 
born ; — that certain male birds undertake the whole duty of 
incubation, and that male pigeons, as well as the females, feed 
their nestlings with a secretion from their crops. But the above 
suggestion first occurred to me from the mammary glands of 
male mammals being so much more perfectly developed than 
the rudiments of the other accessory reproductive parts, which 
are found in the one sex though proper to the other. The 
mammary glands and nipples, as they exist in male mammals, 
can indeed hardly be called rudimentary ; they are merely not 
f Lilly developed, and not functionally active. They are sympa- 
thetically affected under the influence of certain diseases, like 
the same organs in the female. They often secrete a few drops 
of milk at birth and at puberty : this latter fact occurred in the 
curious case, before referred to, where a young man possessed 
two pairs of mammae. In man and some other male mammals 
these organs have been known occasionally to become so well 
developed during maturity as to yield a fair supply of milk. 
Now if we suppose that during a former prolonged jDcriod male 
mammals aided the females in nursing their offspring,^^ and that 
afterwards from some cause (as from the production of a smaller 
number of young) the males ceased to give this aid, disuse of the 
organs during maturity would lead to their becoming inactive ; 
and from two well-known principles of inheritance, this state of 
inactivity would probably be transmitted to the males at the 
corresponding age of maturity. But at an earlier age these 

'° Mr. Lockwood believes (ns by Prof. Wyman, in ' Proc. Boston 
quoted in 'Quart. Journal of Science,' Soc. of Nat. Hist.' Sept. 15,1857; 
April, 1868, p. 269), from what he also Prof. Turner, in 'Journal of 
has observed of the development of Anat. and Phys.' Nov. 1, 186(3, p. 
Hippocampus, that the walls of the 78. Dr. Giinther has de- 
abdominal pouch of the male in scribed similar cases, 
some way aflbrd nourishment. On '' Madlle. C. Pvoyer has suggested 
male fishes hatching the ova in their a similar view in her ' Origine de 
mouths, see a very interesting paper I'Homme,' (S:c., 1870. 

1 64 The Descent of Man. Part I. 

organs would be left unaffected, so that they would be almost 
equally well developed in the young of both sexes. 

Conclusion. — Yon Baer has defined advancement or progress in 
the organic scale better than any one else, as resting on the 
amount of differentiation and specialisation of the several parts 
of a being, — when arrived at maturity, as I should be inclined to 
add. Now as organisms have become slowly adapted to diver- 
sified lines of life by means of natural selection, their parts will 
have become more and more differentiated and specialised for 
various functions, from the advantage gained by the division of 
physiological labour. The same part appears often to have been 
modified first for one purpose, and then long afterwards for 
some other and quite distinct purpose ; and thus all the parts 
are rendered more and more complex. But each organism still 
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 organisa- 
tion on the whole has advanced throughout the world by slow 
and interrupted steps. In the great kingdom of the Vertebrata 
it has culminated in man. It must not, however, be supposed 
that groups of organic beings are always supplanted, and dis- 
appear as soon as they have given birth to other and more 
perfect groups. The latter, though victorious over their pre- 
decessors, may not have become better adapted for all places in 
the economy of nature. Some old forms appear to have survived 
from inhabiting protected sites, where they have not been 
exposed to very severe competition ; and these often aid us in 
constructing our genealogies, by giving us a fair idea of former 
and lost populations. But we must not fall into the error of 
looking at the existing members of any lowly-organised group as 
perfect representatives of their ancient predecessors. 

The most "ancient progenitors in the kingdom of the Vertebrata, 
at which we are able to obtain an obscure glance, apparently 
consisted of a group of marine animals,^^ resembling the larvae of 
existing Ascidians. These animals probably gave rise to a 

3^ The inhabitants of the sea- ditions for many generations, can 
.shore must be greatly affected by hardly fail to run their course in 
the tides; animals living either regular weekly periods. Now it is a 
aboixt the mean high-water marlv, mysterious fact that in the higher 
or about the mean low-water mark, and now terrestrial Vertebrata, as 
pass through a complete cycle of well as in other classes, many nor- 
tidal changes in a fortnight. Con- mal and abnormal processes have 
sequently, their food supply will one or more whole weeks as their 
undergo marked changes week by periods ; this would be rendered 
week. The A'ital functions of such intelligible if the Vertebrata are de- 
animals, living under these con- scended from an animal allied to 

Chap. VJ, Affinities and Genealogy. 165 

group of fishes, as lowly organised as the lancelet ; and from 
these the Ganoids, and other fishes like the Lcpidosiren, must 
have been developed. From such fish a very small advance 
would carry us on to the Amphibians. AYe 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 thuy 
ascend to the Lemuridse ; and the interval is not very wide from 
these to the Simiadae. The Simiadse then branched off into two 
great stems, the New World and Old World monkeys ; and from 
the latter, at a remote period, Man, the wonder and glory of the 
Universe, i^roceeded. 

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 recognise our parentage ; 
nor need we feel ashamed of it. The most humble organism is 
something much higher than the inorganic dust under our feet ; 
and no one with an unbiassed mind can study any living 
creature, however humble, without being struck with enthusiasm 
at its marvellous structure and properties. 

the existing tidal Asoirlians. ^Many cess or function, would not, when 
instances ot" such periodic processes once gained, be liable to change; 
might be given, as the gestation of consequently it might be thus trans- 
mammals, the duration ot" fevers, &c. mitted through almost any number 
The hatching of eggs affords also a of geneivitions. But if the function 
good example, for, according to Mr. changed, the period would have to 
Bartlett (' Land and Water,' Jan. 7, change, and would be apt to change 
1871), the eggs of the pigeon are almost abruptly by a whole week, 
hatched in two weeks ; those of the This conclusion', if sound, is highly 
fowl in three ; those of the duck in remarkable ; for the period of gesta- 
four ; those of the goose in five ; tion in each mammal, and the 
and those of the ostrich in seven hatching of each bird's eggs, and 
weeks. As far as we can judge, a many other vital processes, thus 
recurrent period, if approximately betray to us the primordial birth- 
of the right duration tor any pro- place of these animals. 

1 66 The Descent of Man. Tabt I. 

On the Eaces of Man. 

The nature and value of specific characters — Application to the races of 
ii:an — Arguments in favour of, and opposed to, ranking the so-called 
races of man as distinct species — Sub-species — Monogenists and poly- 
genists — Convergence of character — Numerous points of resemblance in 
body and mind between the most distinct races of man — The state of 
man when he first spread over the earth — Each race not descended from 
a single pair — The extinction of races — The formation ot races — The 
effects of crossing — Slight influence of the direct action of the con- 
ditions of life — Slight or no influence of natural selection — Sexual 

It is not iny intention here to describe the several so-called races 
of men ; but I am about to enquire what is the value of the dif- 
ferences between them under a classificatory point of view, and 
how they have originated. In determining whether two or more 
allied forms ought to be ranked as species or varieties, naturalists 
are practically guided by the following considerations; namely, the 
amount of difference between them, and whether such differences 
relate to few or many points of structure, and whether they are 
of physiological importance ; but more especially whether they 
are constant. Constancy of character is what is chiefly valued 
and sought for by naturalists. "Whenever it can be shewn, or 
rendered probable, that the forms in question have remained 
distinct for a long period, this becomes an argument of much 
weight in favour of treating them as species. Even a slight 
degree of sterility between any two forms when first crossed, or 
in their offspring, is generally considered as a decisive test of 
their specific distinctness; and their continued persistence 
without blending witliin the same area, is usually accepted as 
sufficient evidence, either of some degree of mutual steiility, 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 variable 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 

Ohap. TIT. The Races of Man, 167 

of the other inhabitants are specifically distinct, are themselves 
usually looked at as distinct ; but in truth this affords no aid in dis- 
tinguishing geographical races from so-called good or true species. 

Now let us apply these generally- admitted principles to the 
races of man, viewing him in the same spirit as a naturalist would 
any other animal. In regard to the amount of difference between 
the races, we must make some allowance for our nice powers of 
discrimination gained by the long habit of observing ourselves. 
In India, as Elphinstone remarks, although a newly-arrived 
European cannot at first distinguish the various native races, 
yet they soon appear to him extremely dissimilar ■} and the 
Hindoo cannot at first perceive any difference between the several, 
European nations. Even the most distinct races of man are 
much more like each other in form than would at first be sup- 
posed ; certain negro tribes must be excepted, whilst others, as 
Dr. Eohlfs writes to me, and as I have myself seen, have 
Caucasian features. This general similarity is well shewn by 
the French photographs in the Collection Anthropologique du 
]\Iuseum de Paris of the men belonging to various races, the 
greater number of which might pass for Europeans, as many 
persons to whom I have shewn them have remarked. Neverthe- 
less, these men, if seen alive, would undoubtedly appear very 
distinct, so that we are clearly much influenced in our judgment 
by the mere colour of the skin and hair, by slight differences in 
the features, and by expression. 

There is, however, no doubt that the various races, when 
carefully compared and measured, differ much from each other, 
— as in the texture of the hair, the relative proportions of all parts 
of the body,^ 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 acclimatisation 
and in liability to certain diseases. Their mental characteristics 
are likewise very distinct ; chiefly as it would appear in their 
emotional, but partly in their intellectual faculties. Every one 
who has had the opportunity of comparison, must have been 

* 'History of India,' 184-1, vol. i. 'On the capacity of the lungs,' p. 471. 

p. 323. Father Ripa makes exactly See also the numerous and valuable 

the same remark with respect to tables, by Dr. Weisbach, fi-om the 

the Chinese. observations of Dr. Scherzer and 

2 A vast number of measure- Dr. Schwarz, in the ' Reise der 
ments of Whites, Bhicks, and In- Kovara : Anthropolog. Theil,' 1867. 
dians, are given in the 'Investiga- •* See, for instance, Mr. Marshall's 
tions in the Military and Anthropo- account of the brain of a Bush- 
log. Statistics of American Soldiers,' woman, in 'Phil. Transact.' 186-1-, 
by B. A. Gould, 1869, pp. 298-358 ; p. 519. 

1 68 The Descent of Man. Part I. 

struck with the contrast between the taciturn, even morose, 
aborigines of S. America and the light-hearted, talkative negroes. 
There is a nearly similar contrast between the IMalays and the 
Papuans,* who live under the same physical conditions, and are 
separated from each other only by a narrow space of sea. 

We will first consider the arguments which may be advanced 
in favour of classing the races of man as distinct species, and 
then the arguments on the other side. If a naturalist, who had 
never before seen a Negro, Hottentot, Australian, or Mongolian, 
were to compare them, he would at once perceive that they 
differed in a multitude of characters, some of slight and some of 
considerable importance. On enquiry he would find that they 
were adapted to live under widely different cUmates, and that 
they differed somewhat in bodily constitution and mental dis- 
position. If he were then told that hundreds of similar specimens 
could be brought from the same countries, he would assuredly 
declare that they were as good species as many to which he had 
been in the habit of affixing specific names. This conclusion 
would be greatly strengthened as soon as he had ascertained that 
these forms had all retained the same character for many 
centuries ; and that negroes, apparently identical with existing 
negroes, had lived at least 4000 years ago.^ He would also hear, 
on the authority of an excellent observer, Dr. Lund,^ that the 
human skulls 'found in the caves of Brazil, entombed with many 
extinct mammals, belonged to the same tyj)e as that now pre- 
vaibng throughout the American Continent. 

< Wallace, 'The Malay Archi- man (' Races of Man,' 1850, p. 201), 

pelago,' vol. ii. 1869, p. 178. speaking of young Men?.non (the 

^ With respect to the figures in same as Rameses II., as I am in- 

the famous Egyptian caves of Abou- formed by Mr. Birch), insists in the 

Simbel, M. Pouchet says ( ' The strongest manner that he is identical 

Plurality of the Human Races,' Eng. in character with the Jev/s of Ant- 

translat. 1861:, p. 50), that he was werp. Again, when I looked at the 

far from finding recognisable repre- statue of Amunoph III., I agreed with 

sentations of the dozen or more two officers of the establishment, 

nations which some authors beliere both competent judges, that he had 

that they can recognise. Even some a strongly marked negro type of 

of the most strongly-marked races features; but Messrs. Nott and 

cannot be identified with that de- Gliddon (ibid. p. 146, fig. 53) de- 

gi"oe of unanimity which might have scribe him as a hybrid, but not of 

been expected from what has been " negro intermixture." 

written on the subject. Thus ^ As quoted by Nott and Gliddon, 

Messrs. Nott and Gliddon ('Types 'Types of Mankind,' 1854, p. 439. 

of Mankind,' p. 148) state that They give also corroborative evi- 

Rameses II., or the Great, has dence ; but C. Vogt thinks that the 

features suped'bly European ; where- subject requires further investiga- 

as Knox, another firm believer in tion. 
the specific distinctness of the races of 

(Jhap. VJI. The Races of Man. 169 

Our naturalist would then perhaps turn to geographical dis- 
tribution, and he would probably declare that those forms must 
be distinct species, which differ not only in aj^pcarance, but 
are fitted for hot, as well as damp or dry countries, and for the 
Arctic regions. He might appeal to the fact that no species in 
the group next to man, namely the Quadrumana, can resist a low 
temperature, or any considerable change of climate ; and that 
the species which come nearest to man have never been reared 
to maturity, even under the temperate climate of Europe. He 
would be deeply impressed with the fact, first noticed by Agassiz," 
that the different races of man are distributed over the world in 
the same zoological provinces, as those inhabited by undoubtedly 
distinct species and genera of mammals. This is manifestly the 
case with the Australian, Mongolian, and Negro races of man ; in 
a less well-marked manner with the Hottentots; but plainly 
with the Papuans and Malays, who are separated, as Mr. Wallace 
has shewn, by nearly the same line which divides the great 
Malayan and Australian zoological provinces. The Aborigines 
of America range throughout the Continent ; and this at first 
appears opposed to the above rule, for most of the productions of 
the Southern and Northern halves differ widely : yet some few 
living forms, as the opossum, range from the one into the other, 
as did formerly some of the gigantic Edentata. The Esquimaux, 
like other Arctic animals, extend round the whole polar regions. 
It should be observed that the amount of difference between the 
mammals of the several zoological provinces does not correspond 
with the degree of separation between the latter ; so that it can 
hardly be considered as an anomaly that the Negro differs more, 
and the American much less from the other races of man, than 
do the mammals of the African and American continents from 
the mammals of the other provinces. Man, it may be added, 
does not appear to have aboriginally inhabited any oceanic island ; 
and in this respect he resembles the other members of his class. 

In determining whether the supposed varieties of the same 
kind of domestic animal should be ranked as such, or as spe- 
cifically distinct, that is, whether any of them are descended from 
distinct wild species, every naturalist would lay much stress on 
the fact of their external parasites being specifically distinct. 
All the more stress would be laid on this fact, as it would be an 
exceptional one ; for I am informed by Mr. Denny that the most 
different kinds of dogs, fowls, and pigeons, in England, are 
infested by the same species of Pediculi or lice. Now Mr. A. 
Murray has carefully examined the Pediculi collected in different 

' 'Diversity of Origin of the Pluman Races,' in the 'Christian 
Examiner,' July 1850. 

I/O The Descent of Man. Tart T. 

countries from the different races of man ; * and he finds that 
they differ, not only in coloiir, but in the structure of their 
claws and limbs. In every case in -svliicli many specimens were 
obtained the differences were constant. The surgeon of a whaling 
ship in the Pacific assured me that when the Pediculi, with 
which some Sandwich Islanders on board swarmed, strayed on 
to the bodies of the Enghsh sailors, they died in the course of 
three or four days. These Pediculi were darker coloured, and 
appeared different from those proper to the natives of Chiloe in 
South America, of which he gave me Sjoecimens. These, again, 
appeared larger and much softer than European lice. Mr. 
Murray procured four kinds from Africa, namely from the Negroes 
of the Eastern and Western coasts, from the Hottentots and 
Kaflirs ; two kinds from the natives of Australia ; two from North 
and two from South America. In these latter cases it may be 
presumed that the Pediculi came from natives inhabiting different 
districts. With insects shght structural differences, if constant, 
are generally esteemed of specific value : and the fact of the 
races of man being infested by parasites, which appear to be 
specifically distinct, might fairly be urged as an argument that 
the races themselves ought to be classed as distinct species. 

Our supposed naturalist having proceeded thus far in his 
investigation, would next enquire whether the races of men, when 
crossed, were in any degree sterile. He might consult the work* 
of Professor Broca, a cautious and i^bilosophical observer, and in 
this he would find good evidence that some races were quite 
fertile together, but evidence of an opposite nature in regard to 
other races. Thus it has been asserted that the native women of 
Australia and Tasmania rarely produce children to European 
men ; the evidence, however, on this head has now been shewn 
to be almost valueless. The half-castes are killed by the pure 
blacks : and an account has lately been published of eleven half- 
caste youths murdered and burnt at the same time, whose 
remains were found by the police.^'^ Again, it has often been 
said that when mulattoes intermarry they produce few children; 
on the other hand, Dr. Bachman of Charleston" positively 

* 'Transact. R. Soc. of Edinburgh,' who have borne children to a white 
vol. xxiL 1861, p. 567. man are afterwards sterile with 

* ' On the Phenomena of Hybridity their own race, is disproved. M. A. 
m the Genus Homo,' Eng. transhit. de Quatrefages has also collected 
1864. (' Revue des Cours Scientifiques,' 

'" See the interesting letter by March 1869, p. 239) much evidence 

Mr. T. A. Murray, in the ' Anthro- that Australians and Europeans are 

polog. Review,' April 1868, p. liii. not sterile when crossed. 
la this letter Count Strzelecki's *^ ' An Examination of Prof, 

statement, that Australian women Agassiz's Sketch of the Nat. Pro- 

Chap. VII. The Races of Man. 17 1 

asserts that lie lias known mulatto families wliioli have inter- 
married for several generations, and have continued on an 
average as fertile as either pure whites or pure blacks. Enquiries 
formerly made by Sir C. Lyell on this subject led him, as he 
informs me, to the same conclusion.'- In the United States the 
census for the year 1851 included, according to Dr. Bachman, 
405,751 mulattoes ; and this number, considering all the circum- 
stances of the case, seems small ; but it may 2:»art]y 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 considera- 
tion from their lessened fertility, may perhaps be advanced as 
a proof of the specific distinctness of the jDarent races. No doubt 
both animal and vegetable hybrids, when j)roduced from extremely 
distinct species, are liable to premature death; but the parents 
of mulattoes cannot be put under the category of extremely 
distinct species. The common Mule, so notorious for long life 
and vigour, and yet so sterile, shews how little necessary con- 
nection there is in hybrids between lessened fertility and vitality ; 
other analogous 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 not safe criterions of specific 
distinctness. We know that these qualities are easily affected 
by changed conditions of life, or by close inter-breeding, and that 
they are governed by highly complex laws, for instance, that of 
the unequal fertility of converse crosses between the same two 
species. With forms which must be ranked as undoubted 
species, a perfect series exists from those which are absolutely 
sterile when crossed, to those which are almost or completely 

viucesof the Animal World,' Charles- the children are i^^ii and sickly, 

ton, 1855, p. 44. This belief, as Mr. Reade remarks, 

^2 Dr. Rohlt's writes to me that deserves attention, as white men 

he found the mixed races in the have visited and resided on the Gold 

Great Sahara, derived from Arabs, Coast for four hundred years, so 

Berbers, and Negroes of three tribes, that the natives have had ample 

extraordinarily fertile. On the other time to gain knowledge through 

hand, Mr. VViuwood Reade informs experience. 

me that the Negroes ou the Gold '^ ' Military and Anthropolog. 

Coast, though admiring white men Statistics of American Soldiers,' by 

and mulattoes, have a maxim that B. A. Gould, 18G9, p. 319. 
mulattoes should not intermarrv, as 


The Descent of Man. 

Part T. 

fertile. The degrees of sterility do not coincide strictly with 
the degrees of difference between the parents in external structure 
or habits of life. Man in many respects may be compared with 
those animals which have long been domesticated, and a large 
body of evidence can be advanced in favour of the Pallasian 
doctrine/* that domestication tends to eliminate the sterility 
which is so general a result of the crossing of species in a state 
of nature. From these several considerations, it may be justly 
urged that the perfect fertility of the intercrossed races of man, 
if estabnshed, would not absolutely preclude us from ranking 
them as distinct species. 

Independently of fertility, the characters presented by the off- 
spring from a cross have been thought to indicate whether or not 
the parent-forms ought to be ranked as species or varieties ; but 
after carefully studying the evidence, I have come to the con- 
clusion that no general rules of this kind can be trusted. The 
ordinary result of a cross is the production of a blended or 

'* ' The 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 in- 
capacity of certain trees to be graft- 
ed together, is incidental on other 
acquired differences. The nature 
of these differences is unknown, but 
they relate more especially to the re- 
productive system, and much less so 
to external structure or to ordinary 
differences in constitution. One 
important element in the sterility 
of crossed species apparently lies in 
one or both having been long habi- 
tuated to fixed conditions ; for we 
know that changed conditions have 
a special influence on the repro- 
diictive system, and we have good 
reason to believe (as before re- 
marked) that the fluctuating con- 
ditions of domestication tend to 
eliminate that sterility which is so 
general with species, in a natural 
state, when crossed. It has else- 
where been shewn by me (ibid. vol. 
ii. p. 185, and 'Origin of Species' 
5th edit. p. 317), that the sterility 
of crossed species has not been ac- 
quired through natural selection : 
we can see that when two forms 
have already been rendered very 

sterile, it is scarcely possible that 
their sterility should be augmented 
by the preservation or survival of 
the more and more sterile indi- 
viduals ; for as the sterility in- 
creases, fewer and fewer offspring 
will be produced from which to 
breed, and at last only single in- 
dividuals will be produced, at the 
rarest intervals. But there is even 
a higher grade of sterility than 
this. Both Gartner and Kolreuter 
have proved that in genera of plants 
including many species, a series 
can be formed from species which 
when crossed yield fewer and fewer 
seeds, to species which never pro- 
duce a single seed, but yet are 
affected by the pollen of the other 
species, as shewn by the swelling 
of the germen. It is here mani- 
festly impossible to select the more 
sterile individuals, which have al- 
ready ceased to yield seeds ; so that 
the acme of sterility, when the 
germen alone is affected, cannot 
have been gained through selection. 
This acme, and no doubt the other 
grades of steriiity, are the incidental 
results of certain unknown differ- 
ences in the constitution of the re- 
productive system of the species 
which are crossed. 

Chap. Yll. The Races of Man. 173 

intermediate form ; but in certain cases some of the ofiFspring 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 mulattocs commonly present an intermediate 

We have now seen that a naturalist might feel himself fully 
justified in ranking the races of man as distinct species ; for he 
has found that they are distinguished by many differences in 
structure and constitution, some being of importance. These 
differences have, also, remained nearly constant for very long 
periods of time. Our naturalist will have been in some degree 
influenced by the enormous range of man, which is a great 
anomaly in the class of mammals, if mankind be viewed as a 
single species. He will have been struck w^ith the distribution of 
the several so-called races, which accords with that of other 
undoubtedly distinct species of mammals. Finally, he might 
urge that the mutual fertility of all the races has not as yet been 
fully proved, and even if proved would not be an absolute proof 
of their specific identity. 

On the other side of the question, if our supposed naturalist 
were to enquire whether the forms of man keep distinct like 
ordinary species, when mingled together in large numbers in the 
same country, he would immediately discover that this was by 
no means the case. In Brazil he w^ould behold an immense 
mongrel population of Negroes and Portuguese ; in Chiloe, and 
other parts of South America, he would behold the whole popu- 
lation consisting of Indians and Spaniards blended in various 
degrees.^" 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 w^ould find a 
small population of mingled Polynesian and English blood; and 
m the Fiji Archipelago a population of Polynesian and Negritos 

'* ' The Yariatiou of Animals,' success and energy of the Paulistas 

&c., vol. ii. p. 92. in Brazil, who are a much crossed 

'* M. de Quatrefages has given race of Portuguose and Indians, with 

(' Anthropolog. Keview,' Jan. 1869, a mixture of the blood of other 

p. 22) an interesting account of the races. 

1/4 T lie Descent of Man. Part I. 

crossed in all degrees. Many analogous cases could be be added ; 
for instance, in Africa. Hence the races of man are not suf- 
ficiently distinct to inhabit the same country without fusion ; 
and the absence of fusion affords the usual and best test of 
si^ecific 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 negTO slaves in Brazil, who have been imported from all 
parts of Africa. The same remark holds good with the 
Polynesians, and with many other races. It may be doubted 
whether any character can be named which is distinctive of a 
race and is constant. Savages, even within the limits of the 
same tribe, are not nearly so uniform in character, as has been 
often asserted. Hottentot women offer certain peculiarities, 
more strongly marked than those occurring in any other race, 
but these are known not to be of constant occurrence. In the 
several American tribes, colour and hairiness differ considerably; 
as does colour to a certain degree, and the shape of the features 
greatly, in the Negroes of Africa. The shape of the skull varies 
much in some races ;^^ and so it is with every other character. 
Now all naturalists have learnt by dearly-bought experience, how 
rash it is to attempt to define species by the aid of inconstant 

But the most weighty of all the arguments against treating 
the races of man as distinct si)ecies, is that they graduate into 
each other, independently in many cases, as far as we can judge, 
of their having intercrossed. Man has been studied more 
carefully than any other animal, and yet there is the greatest 
possible diversity amongst capable judges whether he should be 
classed as a single species or race, or as two (Virey), as three 
(Jacquinot), as four (Kant), five (Blumenbach), six (Buffon), 
seven (Hunter), eight (Agassiz), eleven (Pickering), fifteen 
(Bory St. Vincent), sixteen (Desmoulins), tw^enty-two (Morton), 
sixty (Crawfurd), or as sixty-three, according to Burke.^^ This 
diversity of judgment does not prove that the races ought not 
to be ranked as sj^ecies, but it shews that they graduate into each 

^^ For instance with the abori- ^* See a good discussion on this 

gines of America and Australia. subject in Waitz, ' Introduct. to 

Prof. Huxley says (' Transact. Inter- Anthropology,' Eng. translat. 1863, 

nat. Congress of Prehist. Arch.' pp. 198-208, 227. I have taken 

1868, p. 105) that the skulls of some of the above statements from 

many South Germans and Swiss are H. Tuttle's ' Origin and Antiquity 

" as short and as broad as those of of Physical Man,' Boston, 1866, p. 

"the Tartars," &c. 35. 

Cii^?. VII. The Races of Man. 175 

other, and tbat it is hardly possible to discover clear distinctive 
characters between tliem. 

Every naturalist who has had the misfortune to undertake the 
description of a group of highly varying organisms, has en- 
countered cases (I speak after experience) precisely like that of 
man ; and if of a cautious disposition, he will end by uniting all 
the forms which graduate into each other, under a single 
species ; for he will say to himself that he has no right to give 
names to objects which he cannot define. Cases of this kind 
occur in the Order which includes man, namely in certain genera 
of monkeys; whilst in other genera, as in Cercopithecus, most of 
the species can be determined with certainty. In the American 
genus Cebus, the various forms are ranked by some naturalists 
as species, by others as mere geographical races. Now if 
numerous sjiecimens of Cebus were collected from all parts of 
South America, and those forms which at present appear to be 
specifically distinct, were found to graduate into each other by 
close steps, they would usually be ranked as mere varieties or 
races ; and this course has been followed by most naturalists 
with respect to the races of man. Nevertheless, it must be 
confessed that there are forms, at least in the vegetable king- 
dom,'^ which we cannot avoid naming as species, but which are 
connected . together by numberless gradations, independently of 

Some naturalists have lately employed the term " sub-species" 
to designate forms which possess many of the characteristics of 
true species, but which hardly deserve so high a rank. Now if 
we reflect on the weighty arguments above given, for raising the 
races of man to the dignity of species, and the insuperable diffi- 
culties on the other side in defining them, it seems that the term 
" sub-species " might here be used with propriety. But from 
long habit the term *' race " will perhaps always be employed. 
The choice of terms is only so far imi3ortant in that it is desirable 
to use, as far as possible, the same terms for the same degrees of 
difiFerence. Unfortunately this can rarely be done : for the larger 
genera generally include closely-aUied forms, which can be 
distinguished only with much difficulty, whilst the smaller 
genera within the same family include forms that are perfectly 
distinct ; yet all must be ranked equally as species. So again, 
species within the same large genus by no means resemble 
each other to the same degree r on the contrary, some of them 

^^ Prof. Nagfli has carefully de- has made analogous remarks on 

Bcribed several striking cases in his some intermediate forms in the 

' Botanische Mittheilungen,' B. ii. Composita; of N. America 
18G6, s. 294-369. Prof. Asa Gray 

176. The Descent of Man. Part I. 

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 anthropologists, 
who are divided into the two schools of monogenists and 
polygenists. Those who do not admit the principle of evolution, 
must look at species as separate creations, or as in some manner 
as distinct entities ; and they must decide what forms of man they 
will consider as species by the analogy of the method commonly 
pursued in ranking other organic beings as species. But it is a 
hopeless endeavour to decide this point, until some definition of 
the term " species " is generally accepted ; and the definition 
must not include an indeterminate element such as an act of 
creation. We might as well attempt without any definition to 
decide whether a certain number of houses should be called a 
village, town, or city. "We have a practical illustration of the 
diflBcultyin the never-ending doubts whether many closely-allied 
mammals, birds, insects, and plants, which represent each 
other respectively in North America and Europe, 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 majority of rising 
men, will feel no doubt that all the races of man are descended 
from a single primitive stock ; whether or not they may think 
fit to designate the races as distinct species, for the sake of ex- 
pressing their amount of difference. ^^ 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 question can arise, for he cannot be said to have been 
domesticated at any particular period. 

During an early stage in the divergence of the races of man 

20 < Origin of Species,' 5th edit, in the ' Fortnightly Review,' 18G5 
p. 68. p. 275. 

*• See Prof. Huxley to this effect 

Chap. VII. The Races of Man. lyj 

from a coramon stock, tlie differences between the races and 
their number must have been small ; consequently as far as 
their distinguishing characters are concerned, they tht n had less 
claim to rank as distinct species than the existing so-called races. 
Nevertheless, so arbitrary is the term of species, that such early 
races would perhaps have been ranked by some naturalists as 
distinct species, if their differences, although extremely slight, 
had been more constant than they are at present, and had not 
graduated into each other. 

It is however possible, though far from probable, that the 
early progenitors of man might formerly have diverged much in 
character, until they became more unlike each other than any 
now existing races; but that subsequently, as suggested by 
Vogt," they converged in character. "When man selects the off- 
spring of two distinct species for the same object, he sometimes 
induces a considerable amount of convergence, as far as general 
appearance is concerned. This is the case, as shewn by Von 
Nathusius,-^ with the improved breeds of the pig, which are 
descended from two distinct species; and in a less marked 
manner with the improved breeds of cattle. A great anatomist, 
Gratiolet, maintains that the anthropomorphous apes do not 
form a natural sub-group ; but that the orang is a highly 
developed gibbon or semnopithecus, the chimpanzee a highly 
developed macacus, and the gorilla a highly developed mandrill. 
If this conclusion, which rests almost exclusively on brain - 
characters, be admitted, w^e should have a case of convergence 
at least in external characters, for the anthropomorphous apes 
are certainly more like each other in many points, than they are 
to other apes. All analogical resemblances, as of a whale to a 
fish, may indeed be said to be cases of convergence; but this 
term has never been applied to superficial and adaptive resem- 
blances. It would, however, be extremely rash to attril)ute to 
convergence close similarity of character in many points of 
structure amongst the modified descendants of widely distinct 
beings. The form of a crystal is determined solely by the mole- 
cular forces, and it is not surprising that dissimilar substances 
should sometimes assume the same form ; but with organic 
beings we should bear in mind that the form of each depends on 
an infinity of complex relations, namely on variations, due to 
causes far too intricate to be followed,— on the nature of the 
variations preserved, these depending on the physicial condi- 

^- ' Lectures oa ^lan,' Eng. trans- schichte, &c., Schweineschildel,' 

lat. 186+, p. 4fi8. 1864, s. 104. With respect to cattle, 

23 ' Die Racen des Schwcines,' see M. de Quatretages, ' Unit<5 de 

I860, s. 46. 'Voistudien fiir Ge- I'Espece Humaine,' 1861, p. 119. 

178 The Descent of Man, Part 1. 

tions, and still more on the surrounding organisms which com- 
pete with each,— and lastly, on inheritance (in itself a fluctuating 
element) from innumerable progenitors, all of which have had 
their forms determined through equally complex relations. It 
appears incredible that the modified descendants of two organ- 
isms, if these differed from each other in a marked manner, 
should ever afterwards converge so closely as to lead to a near 
approach to identity throughout their whole organisation. In 
the case of the convergent races of pigs above referred to, evi- 
dence of their descent from two primitive stocks is, according to 
Von Nathusius, still plainly retained, in certain bones of their 
skulls. If the races of man had descended, as is supposed by 
some naturalists, from two or more species, which differed from 
each other as much, or nearly as much, as does the orang from 
the gorilla, it can hardly be doubted that marked differences in 
the structure of certain bones would still be discoverable in man 
as he now exists. 

Although the existing races of man differ in many respects, as 
in colour, hair, shape of skull, proportions of the body, &c., yet 
if their whole structure be taken into consideration they are 
found to resemble each other closely in a multitude of points. 
Many of these are of so unimportant or of so singular a nature, 
that it is extremely improbable that they should have been inde- 
pendently acquired by aboriginally distinct species or races. 
The same remark holds good with equal or greater force with 
respect to the numerous points of mental similarity between the 
most distinct races of man. The American aborigines, Negroes 
and Europeans are as different from each other in mind as any 
three races that can be named; yet I was incessantly struck, 
whilst living with the Fuegians on board the " Beagle," with the 
many little traits of character, shewing how similar their minds 
were to ours ; and so it was with a full-blooded negro with whom 
I happened once to be intimate. 

He who will read Mr. Tylor's and Sir J. Lubbock's interesting 
works ^^ can hardly fail to be deeply impressed with the close 
similarity between the men of all races in tastes, dispositions and 
habits. This is shewn by the pleasure which they all take in 
dancing, rude music, acting, painting, tattooing, and otherwise 
decorating themselves ; in their mutual comprehension of gesture- 
language, by the same expression in their features, and by the 
same inarticulate cries, when excited by the same emotions. 
This similarity, or rather identity, is striking, when contrasted 

^* Tylor's ' Early History of Man- language, see p. 54. Lubbock's 
kind,' 1865 : with respect to gesture- ' Prehistoric T'mes,' 2nd edit. 1869. 

Chap. VI r. TJie Races of Man. 179 

with the different expressions and erics made by distinct species 
of monkeys. There is good evidence that tlie art of sliooting 
with bows and arrows has not been lianded down from any 
common progenitor of mankind, yet as Westroi)p 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 archaeologists ^^ 
with respect to certain widely-prevalent ornaments, such as zig- 
zags, &c. ; and with respect to various simple beliefs and cus- 
toms, such as the burying of the dead under megalithic struc- 
tures. I remember observing in South America,^^ that there, as 
in so many other parts of the world, men have generally chosen 
the summits of lofty hills, to throw uj) piles of stones, either as 
a record of some remarkable event, or for burying their dead. 

Now when naturalists observe a close agreement in numerous 
small details of habits, tastes, and dispositions between two or 
more domestic races, or between nearly-allied natural forms, 
they use this fact as an argument that they are descended from a 
common progenitor who was thus endowed ; and consequently 
that all should be classed under the same species. The same 
argument may be applied with much force to the races of man. 

As it is improbable that the numerous and unimportant points 
of resemblance between the several races of man in bodily struc- 
ture 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, pre- 
ceded any great amount of divergence of character in the several 
races ; for otherwise we should sometimes meet with the same 
race in distinct continents ; and this is never the case. Sir J. 
Lubbock, after comparing the arts now practised by savages in 
all parts of the world, sjDecifies those which man could not have 
known, when he first wandered from his original birth-place ; 
for if once learnt they would never have been forgotten.'-** He 

2^ 'On Analogous Forms of Im- 'Journal of Ethnological Soc' as 

plenients,' in 'Memoirs of Anthropo- given in * Scientific Opinion,' June 

log. Soc.,' by H. M. Westropp. 'The 2ud, 1869, p. 3. 

Primitive Inhabitants of Scandi- ^^ 'Journal of Researches: Voyage 

navia,' Eng. transFat. edited by Sir of the "Beagle,"' p. 46. 

J. Lubbock, 1868, p. 104-. "-* 'Prehistoric Times,' 1809, p. 

2« Westropp, ' On CDmlechs/ &c., 574. 

l8o The Descent of Man. Part I. 

tlms shews that " the spear, which is but a development of the 
" knife-point, and the club, which is but a long hammer, are the 
" only things left." He admits, however, that the art of making- 
lire 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 
remarks 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." Nevertheless, at 
this early p)eriod, the intellectual and social faculties of man 
could hardly have been inferior in any extreme degree to those 
possessed at present by the lowest savages ; otherwise primeval 
man could not have been so eminently successful in the struggle 
for life, as proved by his early and wide diffusion. 

From the fundamental differences between certain languages, 
some philologists have inferred that when man first became 
widely diffused, he was not a speaking animal ; but it may be 
suspected that languages, far less perfect than any now spoken, 
aided by gestures, might have been used, and yet have left no 
traces on subsequent and more highly-developed tongues. With- 
out the use of some language, however imperfect, it appears 
doubtful whether man's intellect could have risen to the 
standard implied by his dominant position at an early period. 

"Whether primeval man, when he possessed but few arts, and 
those of the rudest kind, and when his power of language was 
extremely imperfect, would have deserved to be called man, must 
depend on the definition wliich 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 apj^ears the 
more appropriate. Finally, we may conclude that when the 
principle of evolution is generally accepted, as it surely will be 
l3efore long, the dispute between the monogenists and the poly- 
genists will die a silent and unobserved death. 

One other question ought not to be passed over without notice, 
namely, whether, as is sometimes assumed, each sub-sj)ecies or 
race of man has sprung from a single pair of progenitors. With 

Chap. VII. TJie Extinction of Races. 1 8 1 

oui* domestic animals a new race can readily be formed by care- 
fully matching the varying ofiFspring from a single pair, or even 
from a single individual possessing some new character; but 
most of our races have been formed, not intentionally from a 
selected pair, but unconsciously by the preservation of many in- 
dividuals which have varied, however slightly, in some useful or 
desired manner. If in one country stronger and heavier horses, 
and in another country lighter and fleeter ones, were habitually 
preferred, we may feel sure that two distinct sub-breeds would 
be produced in the course of time, without any one pair having 
been separated and bred from, in either country. Many races 
have been thus formed, and their manner of formation is closely 
analogous to that of natural species. We know, also, that the 
horses taken to the Falkland Islands have, during successive 
generations, become smaller and weaker, whilst those which have 
run wild on the Pampas have acquired larger and coarser heads ; 
and such changes are manifestly due, not to any one pair, but to 
all the individuals having been subjected to the same conditions, 
aided, perhaps, by the principle of reversion. The new sub- 
breeds in such cases are not descended from any single pair, but 
from many individuals which have varied in different degrees, 
but in the same general manner ; and we may conclude that the 
races of man have been similarly produced, the modifications 
being either the direct result of exposure to different conditions, 
or the indirect result of some form of selection. But to this 
latter subject we shall presently return. 

On the Extinction of the Eacesof 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 
])reserved by the present inhabitants, indicate much extinction, 
Some small and broken tribes, remnants of former races, still 
survive in isolated and generally mountainous districts. In 
Europe the ancient races were all, according to Schaaffhausen,-" 
" 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 Professor Broca from Les Eyzies, 
though they unfortunately appear to have belonged to a single 
family, indicate a race with a most singular combination of low 
or simious, and of high characteristics. This race is " entirely' 

29 Translation in 'Anthropological Review,' Oct. 1868, p. 431 

1 82 The Descent of Man. Part I. 

" different from any other, ancient or modern, that we have ever 
"heard of."^° It differed, therefore, from the quaternary race of 
the caverns of Belgium. 

Man can long resist conditions which appear extremely un- 
favourable 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 with- 
out the protection of clothes, or of any building worthy to be 
called a hovel. In South Africa the aborigines wander over arid 
plains, where dangerous beasts abound. Man can withstand the 
deadly influence of the Terai at the foot of the Himalaya, and 
the pestilential shores of tropical Africa. 

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 savage tribe, — such 
as periodical famines, nomadic habits and the consequent deaths 
of infants, prolonged suckling, wars, accidents, sickness, licen- 
tiousness, the stealing of women, infanticide, and especially 
lessened fertility. If any one of these checks increases in power, 
even slightly, the tribe thus aft'ected tends to decrease ; and 
when of two adjoining tribes one becomes less numerous and less 
powerful than the other, the contest is soon settled by war, 
slaughter, cannibalism, slavery, and absorption. Even when a 
weaker tribe is not thus abruptly swept away, if it once begins 
to decrease, it generally goes on decreasing until it becomes 

When civilised nations come into contact with barbarians the 
struggle is short, except where a deadly climate gives its aid to 
the native race. Of the causes which lead to the victory of 
civilised nations, some are plain and simple, others complex and 
obscure. We can see that the cultivation of the land will 
be fatal in many ways to savages, for they cannot, or will not, 
change their habits. New diseases and vices have in some cases 
proved highly destructive; and it appears that a new disease 
often causes much death, until those who are most susceptible 
to its destructive influence are gradually weeded out f^ and so it 
may be with the evil effects from spirituous liquors, as well as 
with the unconquerably strong taste for them shewn by so many 

^^ 'Transact, Internat. Congress terben der NatuvA^olker,' 1868, s. 82. 

of Prehistoric Arch,' 1868, pp. 172- ^^ Gerland (ibid. s. 12) gives facts 

• 175. See also Broca (translation) in support of this statement. 

in ' Anthropological Review,' Oct. ^^ See remarks to this effect in 

1868, p. 410. Sir H. Holland's ' Medical Notes and 

31 Dr. Gerland ' Ueber das Auss- Reflections,' 1839, p. 390. 

Chap. VI [. The Extinction of Races. 1S3 

savages. It further appears, mysterious as is the fact, that 
the first meeting of distinct and separated people generates 
disease.^^ Mr. Sproat, wlio in Vancouver Island closely attended 
to the subject of extinction, believed that changed habits of life, 
consequent on the advent of Europeans, induces much ill health. 
He lays, also, great stress on the apparently trifling cause that 
the natives become '' bewildered and dull by the new life around 
" them ; they lose the motives for exertion, and get no new ones 
" in their place." ^^ 

The grade of their civilisation seems to be a most important 
element in the success of competing nations. A few centuries 
ago Europe feared the inroads of Eastern barbarians ; now any 
such fear would be ridiculous. It is a more curious fact, as 
Mr. Bagehot has remarked, that savages did not formerly waste 
away before the classical nations, as they now do before modern 
civilised nations; had they done so, the old moralists would 
have mused over the event ; but there is no lament in any writer 
of that period over the perishing barbarians.^^ The most po- 
tent of all the causes of extinction, appears in many cases to be 
lessened fertility and ill-health, especially amongst the children, 
arising from changed conditions of life, notwithstanding that the 
new conditions may not be injurious in themselves. I am much 
indebted to Mr. H. H. Howorth for having called my attention to 
this suliject, and for having given me information respecting it. 
I have collected the following cases. 

When Tasmania was first colonised the natives were roughly 
estimated by some at 7000 and by others at 20,000. Their 
number was soon greatly reduced, chiefly by fighting with the 
English and with each other. After the famous hunt by all the 
colonists, when the remaining natives delivered themselves up 
to the government, they consisted only of 120 individuals,^'^ 
who were in 18o2 transported to Flinders Island. This island, 
situated between Tasmania and Australia, is forty miles long, 
and from twelve to eighteen miles broad: it seems healthy, 
and the natives were well treated. Nevertheless, they suffered 
greatly in health. In 1834 they consisted (Bon wick, 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. 

" I have collected ('Journal of Savage Life,' 18G8, p. 284-. 
Researches, Voyage of the "Beagle,"' ^'^ Bagehot, ' I'hysics and Poli- 

p. 435) a good many cases bearing tics,' ' Fortnightly Review,' April 

on this subject: see also Geriand, 1, 18<J8, p. 455. 
ibid. s. 8. Poepidg speaks of the ^^ All the statements here given 

" breath of civilisation as poisonous are taken from 'The last of the 

"to savages." Tasmanians,' by J. Bonwick, 1870. 

'•^ Sproat, ' Scenes and Studies ot 

1 84 The Descent of Man. Part I. 

As tliey continued rapidly to decrease, and as they themselves 
thought that they should not perish so quickly elsewhere, they were 
removed in 1847 to Oyster Cove in the southern part of Tasmania. 
They then consisted (Dec. 20th, 1847) of fourteen men, twenty- 
two women and ten children.^^ But the change of site did no good. 
Disease and death still pursued them, and in 1864 one man (who 
died in 1869), and three elderly women alone survived. The 
infertility of the women is even a more remarkable fact than 
the liability of all to ill-health and death. At the time when 
only nine women were left at Oyster Cove, they told Mr. Bonwick 
(p. 386), that only two had ever borne children : and these two 
had together produced only three children ! 

With resj^ect to the cause of this extraordinary state of things. 
Dr. Story remarks that death followed the attemj)ts to civilise 
the natives. " If left to themselves to roam as they were wont 
" and undisturbed, they would have reared more children, and 
'' there would have been less mortality." Another careful 
observer of the natives, Mr. Davis, remarks, " The births have 
" been few and the deaths numerous. This may have been in a 
'' great measure owing to their change of living and food ; but 
" more so to their banishment from the mainland of Van Diemen's 
"Land, and consequent depression of spirits" (Bonwick, jDp. 
388, 390). 

Similar facts have been observed in two widely different 
parts of Australia. The celebrated explorer, Mr. Gregory, told 
Mr. Bonwick, that in Queensland "the want of reproduction 
"was being already felt with the blacks, even in the most 
" recently settled parts, and that decay would set in." Of 
thirteen aborigines from Shark's Bay who visited Murchison 
Eiver, twelve died of consumption within three months.^^ 

The decrease of the Maories of New Zealand has been carefully 
investigated by Mr. Teuton, in an admirable Eeport, 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 progress- 
ing. Although it has hitherto been found impossible to take an 
actual census of the natives, their numbers were carefully 
estimated by residents in many districts. The result seems 
trustworthy, and shows that during the fourteen years, previous 

38 This is the statement of the 1870, p. 90; and the 'Last of the 

Governor of Tasmania, Sir W. Deni- Tasmanians,' 1870, p. 386. 
.son, ' Varieties of Vice-Regal Life,' ^^ 'Observations on the Aboriginal 

1870, vol. i. p. 67. Inhabitants of New Zealand,' pub- 

3^ For these cases, see Bonwick 's lished by the Government, 1859. 
* Daily Life of the Tasmanians,' 

Chap. VII. The Extinction of Races. 185 

to 1858, the decrease was 19.42 per cent. Some of the tribes, 
thus carefully examined, lived above a Inmdrcd miles apart, 
some on the coast, some inland ; and their means of subsistence 
and habits differed to a certain extent (p. 28). The total 
number in 1858 was believed to be 53,700, and in 1872, after a 
second interval of fourteen years, another census was taken, 
and the number is given as only 36,359, shewing a decrease of 
32-29 per cent. ! *^ Mr. Fenton, after shewing in detail the in- 
sufficiency of the various causes, usually assigned in explana- 
tion of this extraordinary decrease, such as new diseases, the 
profligacy of the women, drunkenness, wars, &c., concludes on 
weighty grounds that it depends chiefly on the unproductiveness 
of the women, and on the extraordinary mortality of the young 
children (pp. 31, 34). In proof of this he shews (p. 33) that in 
1844 there was one non-adult for every 2*57 adults; whereas in 
1858 there was only one non-adult for every 3-27 adults. The 
mortality of the adults is also great. He adduces as a further 
cause of the decrease the inequality of the sexes ; for fewer females 
are born than males. To this latter point, depending perhaps 
on a widely distinct cause, I shall return in a future chapter. 
Mr. Fenton contrasts with astonishment the decrease in New 
Zealand with the increase in Ireland ; countries not very dis- 
similar in climate, and where the inhabitants now follow nearly 
similar habits. The Maories themselves (p. 35) " attribute their 
"decadence, in some measure, to the introduction of new food 
"■ and clothing, and the attendant change of habits;" and it will 
be seen, when we consider the influence of changed conditions 
on fertility, that they are probably right. The diminution began 
between the years 1880 and 1840 ; and Mr. Fenton shews (p. 40) 
that about 1830, the art of manufacturing putrid corn (maize), 
by long steeping in water, was discovered and largely practised ; 
and this proves that a change of habits was beginning amongst 
the natives, even when New Zealand was only thinly inhabited 
by Europeans. When I visited the Bay of Islands in 1835, 
the dress and food of the inhabitants had already been much 
modified : they raised potatoes, maize, and other agricultural 
produce, and exchanged them for English manufactured goods 
and tobacco. 

It is evident from many statements in the life of Bishop 
Patteson,^^ that the Melanesians of the New Hebrides and 
neighbouring archipelagoes, suffered to an extraordinary degree 
in health, and perished in large numbers, when they were 

*' 'New Zealand,' by Alex. Ken- C. M. Younge, 1874; see more 
nedy, 1873, p. 47. especially vol. i. p. 530. 

*2 « Life of J. C. Patteson,' by 


The Descent of Man. 

Part I. 

removed to New Zealand, Norfolk Island, and other salubrious 
places, in order to be educated as missionaries. 

The decrease of the native population of the Sandwich Islands 
is as notorious as that of New Zealand. It has been roughly 
estimated by those best capable of judging, that when Cook 
discovered the Islands in 1779, the population amounted to 
about 300,000. According to a loose census in 1828, the 
numbers then were 142,050. In 1832, and at several subsequent 
periods, an accurate census was officially taken, but I have 
been able to obtain only the following returns : 

Annual rate of decrease 

Native ropuLATiON. 

per cent., assuming it 

to have been uniform be- 


(Except during 1832 

tween the successive cen- 

and 1836, when the 

suses ; these censuses be- 

few foreigners in the 

ing taken at irregular 

islands were included). 

















We here see that in the interval of forty years, between 1832 and 
1872, the population has decreased no less than sixty-eight per 
cent. ! This has been attributed by most writers to the profligacy 
of the women, to former bloody wars, and to the severe labour 
imposed on conquered tribes and to newly introduced diseases, 
which have been on several occasions extremely destructive. No 
doubt these and other such causes have been highly efficient, 
and may account for the extraordinary rate of decrease between 
the years 1832 and 1836 ; but the most potent of all the causes 
seems to be lessened fertility. According to Dr. Euschenberger 
of the U.S. Navy, who visited these islands between 1835 and 
1837, in one district of Hawaii, only twenty-five men out of 1134, 
and in another district only ten out of 637, had a family with as 
many as three children. Of eighty married women, only thirty- 
nine had ever borne children ; and " the official report gives an 
" average of half a cliild to each married couple in the whole 

Chap. VII. The Extinction of Races. 187 

" island." This is almost exactly the same average as with the 
Tasmanians at Oyster Cove. Jarves, who published his History 
in 1843, says that " families who have three children are freed from 
" all taxes ; those having more, arc rewarded by gifts of land and 
*' other encouragements." This unparalleled enactment by the 
government well shews how infertile the race had become. The 
Eev. A. Bishop stated in the Hawaiian ' Spectator' in 1839, that a 
large proportion of the children die at early ages, and Bishop 
Staley informs me that this is still the case, just as in New 
Zealand. This has been attributed to the neglect of the children 
by the women, but it is probably in large part due to innate weak- 
ness of constitution in the children, in relation to the lessened 
fertility of their parents. There is, moreover, a further resem- 
blance to the case of New Zealand, in the fact that there is a 
large excess of male over female births : the census of 1872 
gives 31,650 males to 25,247 females of all ages, that is 125-36 
males for every 100 females; whereas in all civilised countries 
the females exceed the males. No doubt the profligacy of the 
women may in part account for their small fertility ; but their 
changed habits of life is a much more probable cause, and which 
will at the same time account for the increased mortality, 
especially of the children. The islands were visited by Cook in 
1779, by Vancouver in 1794, and often subsequently by w^halers. 
In 1819 missionaries arrived, and found that idolatry had been 
already abolished, and other changes effected by the king. After 
this period there was a rapid change in almost all the habits of 
life of the natives, and they soon became " the most civilised of 
" the Pacific Islanders." One of my informants, Mr. Coan, who 
was born on the islands, remarks that the natives have undergone 
a greater change in their habits of life in the course of fifty years 
than Englishman during a thousand years. From information 
received from Bishop Staley, it does not appear that the 
poorer classes have ever much changed their diet, although 
many new kinds of fruit have been introduced, and the sugar- 
cane is in universal use. Owing, however, to their passion for 
imitating Europeans, they altered their manner of dressing at 
an early period, and the use of alcoholic drinks became very 
general. Although these changes appear inconsiderable, I can 
well believe, from what is known with respect to animals, that 
tliey might suffice to lessen the fertility of the natives."*^ 

*' The foregoing statements are Islands,' 1851, p. 277. Ruschen- 

taken chiefly from the following berger is quoted by Bonwick, 'Last 

works: 'Jarves' Histoi-y of the of the Tasmanians,' 1870, p. 378. 

Hawaiian Islauds,' 1843, p. 400-407. Bishop is quoted by Sir E. Belcher, 

Cheever, ' Life in the Sandwich ' Voyage Round the World,' 1843, 

1 88 The Descent of Man. Part 1. 

Lastly, Mr. Macnamara states** tliat 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." Ee further states that the inhabit- 
ants of the Valley of Nepal, which is extremely hot in summer, 
and also the various hill-tribes of India, suffer from dysentery 
and fever when on the plains ; and they die if they attempt to 
pass the whole year there. 

We thus see that many of the wilder races of man are apt to 
suffer much in health when subjected to changed conditions 
or habits of life, and not exclusively from being transported to 
a new climate. Mere alterations in habits, which do not appear 
injurious in themselves, seem to have this same effect ; and in 
several cases the children are particularly liable to suffer. It 
has often been said, as Mr. Macnamara remarks, that man can 
resist with impunity the greatest diversities of climate and other 
changes; but this is true only of the civilised races. Man in 
his wild condition seems to be in this respect almost as sus- 
ceptible as his nearest allies, the anthropoid apes, which have 
never yet survived long, when removed from their native 

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 degree 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 j)rofligacy of the women (as until lately with 
the Tahitians), but Mr. Fenton has shewn 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 arc 
apt to be sterile; but this cannot apply in several of the abovo 
cases. Some writers have suggested that the aborigines of 
islands have suffered in fertility and health from long continued 

vol, i., p. 272. I owe the census of of the above-named works. I have 

the several years to the kindness of omitted the census for 1850, as I 

Mr. Coan, at the request of Dr. You- have seen two widely different num- 

mans of New York ; and in most bers given. 

cases I have compared the Youmans ■** ' The Indian Medical Gazette, 

iigures with those given in several Nov. 1, 1871, p. 240. 

Chap. VII. The Extinction of Races, 1 89 

inter-breeding ; but in the above cases infertility has coincided 
too closely with the arrival of Europeans for us to admit this 
explanation. Nor have we at present any reason to believe 
that man is highly sensitive to the evil effects of inter-breeding, 
especially in areas so large as New Zealand, and the Sandwich 
archipelago with its diversified stations. On the contrary, it is 
known that the present inhabitants of Norfolk Island are nearly 
all cousins or near relations, as are the Todas in India, and the 
inhabitants of some of the Western Islands of Scotland; and 
yet they seem not to have suffered in fertility.'*'' 

A much more probable view is suggested by the analogy of 
the lower animals. The reproductive system can be shewn to be 
susceptible to an extraordinary degree (though why we know 
not) to changed conditions of life ; and this susceptibility leads 
both to beneficial and to evil results. A large collection of facts 
on this subject is given in chap, xviii. of vol. ii. of my ' Variation 
of Animals and Plants under Domestication/ 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, vigour and fertility of most or all organic beings, 
whilst other changes are known to render a large number of 
animals sterile. One of the most familiar cases, is that of tamed 
elephants not breeding in India; though they often breed in 
Ava, where the females are allowed to roam about the forests to 
some extent, and are thus placed under more natural conditions. 
The case of various American monkeys, both sexes of which 
have been kept for many years together in their own countries, 
and yet have very rarely or never bred, is a more apposite in- 
stance, because of their relationship to man. It is remarkable 
how slight a change in the conditions often induces sterility in a 
wild animal when captured ; and this is the more strange as all 
our domesticated animals have become more fertile than they 
were in a state of nature; and some of them can resist the 
most unnatural conditions with undiminished fertility .^^ Certain 
groups of animals are much more liable than others to be 
affected by captivity ; and generally all the species of the same 
group are affected in the same manner. But sometimes a single 
species in a grouiD is rendered sterile, whilst the others are not 
so ; on the other hand, a single species may retain its fertility 

••^ On the close relationship of the Scotland, Dr. Mitchell, 'Edinburgh 

Norfolk Islanders, see Sir W. Deni- Medical Journal,' March to June, 

son, 'Varieties of Vice-Kegal Life,' 1865. 

vol. i. 1870, p. 410. For the Todas, ^° For the evidence on this head, 

see Col. Marshall's work, 1873, p. see 'Variation of Animals' &c., 

110. For the Western Ishinds of vol. ii. p. 111. 

1 90 The Descent of Man. Part 1. 

whilst most of the others fail to breed. The males and females 
of some species when confined, or when allowed to live almost, 
but not quite free, in their native country, never unite ; others 
thus circumstanced frequently unite but never produce offspring ; 
others again produce some offspring, but fewer than in a state 
of nature ; and as bearing on the above cases of man, it is 
important to remark that the young are apt to be weak and 
sickly, or malformed, and to jDerish 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 Quadrimaana, 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 hfe, they become more or less sterile, and their young 
offspring suffer in health, in the same manner and from the same 
cause, as do the elephant and hunting-leopard in India, many 
monkeys in America, and a host of animals of all kinds, on removal 
from their natural conditions. 

We can see why it is that aborigines, who have long inha- 
bited islands, and who must have been long exposed to nearly 
uniform conditions, should be specially affected by any change 
in their habits, as seems to be the case. Civilised races can 
certainly resist changes of all kinds far better than savages; 
and in this respect they resemble domesticated animals, for 
though the latter sometimes suffer in health (for instance 
European dogs in India), yet they are rarely rendered sterile, 
though a few such instances have been recorded.*^ The 
immunity of civilised races and domesticated animals is 
probably due to their having been subjected to a greater extent, 
and therefore having grown somewhat more accustomed, to 
diversified or varying conditions, than the majority of wild 
animals ; and to their having formerly immigrated or been 
carried from country to country, and to different families or 
sub-races having inter-crossed. It appears that a cross with 
civilised races at once gives to an aboriginal race an immunity 
from the evil consequences of changed conditions. Thus the 
crossed offspring from the Tahitians and English, when settled 
in Pitcairn Island, increased so rapidly that the island was soon 
overstocked ; and in June 1856 they were removed to Norfolk 
Island. They then consisted of 60 married persons and 134 
children, making a total of 194. Here they likewise in- 
creased so rapidly, that although sixteen of them returned to Pit- 
cairn Island in 1859, they numbered in January 1868, 300 souls ; 

*^ ' Variation of Animals,' &c., vol. ii., p 16, 

Chap. VII. The Extinction of Races. 191 

the males and females being in exactly equal numbers. What a 
contrast does tliis case present with that of the Tasmanians; 
the Norfolk Islanders increased in only twelve and a lialf years 
from 194 to 300; 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 18G6 and 1872 
the natives of full blood in the Sandwich Islands decreased by 
8081, whilst the half-castes, who are believed to be healthier, in- 
creased by 847 ; but I do not know whether the latter number 
includes tlie 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, 
wlio have been subjected to new conditions as the result of the 
immigration of civilised men. But sterility and ill-health would 
probably follow, if savages were compelled by any cause, such 
as the inroad of a conquering tribe, to desert their homes and 
to change their habits. It is an interesting circumstance that 
the chief check to wild animals becoming domesticated, which 
implies the power of their breeding freely when first cai)tured, 
and one chief check to wild men, when brought into contact 
with civilisation, surviving to form a civilised race, is the same, 
namely, sterility from changed conditions of life. 

Finally, although the gradual decrease and ultimate extinction 
of the races of man is a highly complex problem, depending on 
many causes which differ in different places and at different 
times ; it is the same problem as that presented by the extinc- 
tion of one of the higher animals — of the fossil horse, for in- 
stance, which disappeared from South America, soon afterwards 
to be replaced, within the same districts, by countless troops 
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 

«« These details are taken from Jlay 29th, 1863. The following 

'The Mutineers of the "Bounty,"' statements about the Sandwich Is- 

by Lady Belcher, 1870; and from landers are from the 'Honolulu 

♦Titcairn Island,' ordered to be Gazette,' and from Mr. Coan. 
printed by the House of Commons, 

192 The Descent of Man. Part I. 

later lead to extinction ; the end, in most cases, being promptly 
determined by the inroads of conquering tribes. 

On the Formation of the Races of Man. — In some cases the 
crossing of distinct races has led to the formation of a new race. 
The singular fact that Europeans and Hindoos, who belong to 
the same Aryan stock, and speak a language fundamentally the 
same, differ widely in appearance, whilst Europeans differ but 
little from Jews, who belong to the Semitic stock, and speak 
quite another language, has been accounted for by Broca,^^ 
through certain Aryan branches 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 SantaH or hill-tribes 
of India, says that hundreds of imperceptible gradations may be 
traced " from the black, squat tribes of the mountains to the tall 
" olive-coloured Brahman, with his intellectual brow, calm eyes, 
*'and high but narrow head;" so that it is necessary in courts 
of justice to ask the witnesses whether they are Santalis or 
Hindoos.^" Whether a heterogeneous people, such as the inhabi- 
tants of some of the Polynesian islands, formed by the crossing 
of two distinct races, with few or no pure members left, would 
ever become homogeneous, is not kno\vn 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 generations, we may infer that the free intercrossing of a 
heterogeneous mixture during a long descent would supply the 
place of selection, and overcome any tendency to reversion ; so 
that the crossed race would ultimately become homogeneous, 
though it might not partake in an equal degree of the characters 
of the two parent-races. 

Of all the differences between the races of man, the colour of 
the skin is the most conspicuous and one of the best marked. It 
was formerly thought that differences of this kind could be 
accounted for by long exposure to different climates; but 
Pallas first shewed that this is not tenable, and he has since been 
followed by almost all anthropologists.^^ This view has been 
rejected chiefly because the distribution of the variously 
coloured races, most of whom must have long inhabited their 

*9 *0n Anthropology,' transla- " Pallas, 'Act. Acad. St. Peters- 

tion ' Aathropolog. Keview,' Jan. burg,' 1780, part ii. p. 69. He was 

1868, p. 38. followed by Kudolphi, in his ' Bcy- 

^•^ 'The Annals of Rural Bengal,' trage zur Anthropologic,' 1812. 

1868, p. 134. An excellent summary of the evi- 

^' ' The Variation of Animals and dence is given by Godron, ' De 

Plants under Domestication,' vol. ii. I'Espece,' 1859, vol. ii. p. 246, &c. . 
p. 95. 

CiiAi'. YII. The Formation of Races. 193 

present homes, does not coincide with corresponding differences 
of climate. Some httle weight may be given to such cases as 
that of the Dutch fomihes, who, as we hear on excellent autho- 
rity," have not undergone the least change of colour after 
residing for three centuries in South Africa. An argument on 
the same side may likewise be drawn from the uniform appear- 
ance in various parts of the world of gipsies and Jews, though 
the uniformity of the latter has been somewhat exaggerated.^* 
A very damp or a very dry atmosphere has lx)on supposed to be 
more influential in modifying the colour of the skin than mere 
heat ; but as D'Orbigny in South America, and Livingstone in 
Africa, arrived at diametrically opposite conclusions with respect 
to dampness and dryness, any conclusion on this head must be 
considered as very doubtful. ^^ 

Various facts, which I have given elsewhere, prove that the 
colour of the skin and hair is sometimes correlated in a surpris- 
ing manner with a complete immunity from the action of certain 
vegetable poisons, and from the attacks of certain parasites. 
Hence it occurred to me, that negroes and other dark races 
might have acquired their dark tints by the darker individuals 
escaping from the deadly influence of the miasma of their 
native countries, during a long series of generations. 

I afterwards found that this same idea had long ago occurred 
to Dr. Wells.^^ It has long been known that negroes, 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 fevers, that prevail along at 
least 2600 miles of the shores of Africa, and which annually 
cause one-fifth of the white settlers to die, and another fifth to 
return home invalided.^* This immunity in the negro seems to 
be partly inherent, depending on some unknown peculiarity of 
constitution, and partly the result of acclimatisation. Pouchet** 

*' Sir Andrew Smith, as quoted the Historical Sketch (p. xvi.) to niy 

by Knox, ' Kaces of Man ' 1850, p. ' Origin of Species.' Various cases 

473. of colour correlated with constitu- 

^* See De Quatrefages on this tional peculiarities are given in my 

head, ' Revue des Cours Scienti- ' Variation of Animals under Do- 

fiques,' Oct. 17, 1868, p. 731. mestication,' vol. ii. pp. 227, 335. 

^* Livingstone's ' Travels and Re- ^^ See, for instance, Nott and 

searches in S. Africa,' 1857, pp. Gliddon, ' Types of Mankind,' p. 08. 

338, 329. D'Orbigny, as quoted by *' Major Tulloch, in a i)ai)er read 

Godron, ' De I'Espfece,' vol. ii. p. before the Statistical Sociotv, April 

206. 20th, 1840, and given in the' ' Athe- 

^® See a paper read before the uaium,' 1840, p. 353. 

Royal Soc. in 1813, and published *" 'The Plurality of the Human 

in his Essays in 1818. I have given Race ' (translat.), 1864, p. 60. 
an account of Dr. Wells' views in 

194 The Descent of Man. Part I. 

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 origin- 
ally brought from various parts of Africa and accustomed to the 
climate of the West Indies. That acclimatisation plays a part, 
is shewn by the many cases in which negroes have become some- 
what liable to tropical fevers, after having resided for some time 
in a colder climate.'^° The nature of the climate under which the 
white races have long resided, likewise has some influence on 
them; for during the fearful epidemic of yellow-fever in 
Demerara during 1837, Dr. Blair found that the death-rate of the 
immigrants was proportional to the latitude of the country 
whence they had come. With the negro the immunity, as far as 
it is the result of acclimatisation, implies exposure during a 
prodigious length of time ; for the aborigines of tropical America 
who have resided there from time immemorial, are not exemjDt 
from yellow fever; and the Eev. H. B. Tristram states, that 
there are districts in Northern Africa which the native inhabit- 
ants are compelled annually to leave, though the negroes can 
remain with safety. 

That the immunity of the negro is in any degree correlated 
with the colour 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 between complexion 
and a tendency to consumption, the conjecture seemed to me 
not improbable. Consequently I endeavoured, with but little 
success,^^ to ascertain how far it holds good. The late Dr. 

^^ Quatrefjiges, * Unite de I'Espece " is some limited degree of relation 

Humiiine,' 1861, p. 205. Waitz, " between the colour of the races of 

' Introduct. to Anthropology,' trans- " man and the climate inhabited bv 

lat. vol. i. 1863, p. 124. Living- " them ; the following invostiga- 

stone gives analogous cases in his "'tion seems worth consideration. 

' Travels.' " Namely, whether there is any re- 

"1 In the spring of 1862 I ob- " lation in Europeans between the 

tained permission from the Director- " colour of their hair, and their 

General of the Medical department " liability to the diseases of tropical 

of the Army, to transmit to the "countries. If the surgeons of the 

surgeons of the various regiments " several regiments, when stationed 

on foreign service a blank tabL"!, " in unhealthy tropical districts, 

with the ibllowing appended re- " would be so good as first to count, 

marks, but I have received no re- " as a standard of comparison, how 

turns. " As several well-marked " many men, in the force whence 

" cases have been recorded with " the sick are drawn, have dark 

*' our domestic animals of a relation " and light-coloured hair, and hair 

" between the colour of the dermal " of intermediate or doubtful tints ; 

" appendages and the constitution ; " and if a similar account were 

" and it being notorious that there " kept by the same medical gentle- 

Chap. Vir. The Format ion vf Races. 195 

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. ^Vhen he first arrived as a boy on the coast, an old and 
experienced negro chief predicted from his appearance that this 
would prove the case. Dr. Nicholson, of Antigua, after having 
attended to this subject, writes to me that he does not think that 
dark-coloured Europeans escape the yellow-fever more than 
those that are light-coloured. Mr. J. ]\I. Harris altogether 
denies that Europeans with dark hair withstand a hot climate 
better than other men : on the contrary, experience lias taught 
him in making a selection of men for service on the coast of 
Africa, to choose those with red hair.*'- As far, therefore, as 
these slight indications go, there seems no foundation for the 
hypothesis, that blackness has resulted from the darker and 
darker individuals having survived better during long exposure 
to fever-generating miasma. 

Dr. Sharpe remarks,^^ that a tropical sun, which burns and 
blisters a white skin, does not injure a black one at all ; and, as 
he adds, this is not due to habit in the individual, for children 
only six or eight months old are often carried about naked, and 
are not affected. I have been assured by a medical man, that 
some years ago during each summer, but not during the winter, 
his hands became marked with light brown patches, like. 

" men. of all the men who suffered " of generations." 

" from malarious and yellow fevers, ^- 'Anthropological RcA'iew,' Jan. 

" or from dysentery, it would soon 1866, p. xxi. Dr. Sharpe- also says, 

*' he apparent, after some thousand with respect to India (' Man a Spe- 

*' cases had been tabulated, whether cial Creation,' 1873, p. 118), that 

" there exists any relation between " it has been noticed by some medi- 

" the colour of the hair and consti- " cal otHcers that Europeans with 

" tutional liability to tropical dis- " light hair and florid complexions 

"eases. Perhaps no such relation " sutler less fi'om diseases of tropical 

*' would be discovered, but the in- " countries than persons with dark 

*' vestigation is well worth making. " hair and sallow complexions; 

*' In case any positive result were " and, so far as 1 know, there ap- 

" obtained, it might be of some " pear to be good grounds for this 

" practical use in selecting men for " remark." On the other hand, 

" any particular service. Theoreti- ]\Ir. Heddle, of Sierra Leone " who 

" cally the result would be of high " has had more clerks killed under 

" interest, as indicating one means " him than any other man," by the 

" by which a race of men inhabiting climate of the West African Coast 

"from a remote period an un- (\V. Reade, 'African Sketch Book,' 

'■ healthy tropical climate, might vol. ii. p. 52'J), holds a directly 

" have become dark-coloured by opposite view, as does Capt. Burton, 

"the better preservation of dark- ^^ ' Man a Special Creation,' 1873, 

" haired or dark-complexioned in- p. 119. 
*' dividuals duriusr a long succession 

196 The Descent of Ma7t. Part I. 

although larger than freckles, and that these patches were never 
affected by sun-burning, -whilst the white parts of his skin 
have on several occasions been much inflamed and blistered. 
With the lower animals there is, also, a constitutional difference 
in liability to the action of the sun between those parts of the 
skin clothed with white hair and other parts.^* Whether the 
saving of the skin from being thus burnt is of sufficient impor- 
tance to account for a dark tint having been gradually acquired 
by man through natural selection, I am unable to judge. If it 
be so, we should have to assume that the natives of tropical 
America have lived there for a much shorter time than the 
negroes in Africa, or the PajDuans in the southern parts of the 
Malay archipelago, just as the lighter-coloured Hindoos have 
resided in India for a shorter time than the darker aborigines of 
the central and southern jDarts of the peninsula. 

Although with our present knowledge we cannot account for 
the differences of colour in the races of man, through any 
advantage thus gained, or from the direct action of climate ; yet 
we must not quite ignore the latter agency, for there is good 
reason to believe that some inherited effect is thus produced.*^^ 

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 Col. 
Bernys that during the late war in the United States, good 
evidence was afforded of this fact by the ridiculous appearance 
presented by the German regiments, when dressed in ready-made 
clothes manufactured for the American market, and which were 
much too loug for the men in every way. There is, also, a con- 
siderable body of evidence shewing that in the Southern States 
the house-slaves of the third generation present a markedly 
different appearance from the field-slaves.^^ 

^* ' Variation of Animals and settled in Georgia, have acquired in 

Plants under Domestication,' vol. ii. the course of two generations dark 

pp. 336, 337. hair and eyes. Mr. D. Forbes in- 

^^ See, for instance, Quatrefages forms me that the Quichuas in the 

(' Revue des Cours Scientifiques,' Andes vary greatly in colour, ac- 

Oct. 10, 1868, p. 724) on the effects cording to the position of the valleys 

of residence in Abyssinia and Arabia, inhabited by them, 
and other analogous cases. Dr. ^^ Harlan, ' Medical Piesearches,' 

liolle (' Dcr Mensch, seine Abstam- p. 532. Quatrefages (' Unite' de 

mung,' &c., 1865, s. 99) states, on I'Espece Humaine,' 1861, p. 128) 

the authority <ii Khanikof, that the has collected much evidence on this 

greater number of German families head. 

Chap. VII. The Formation of Races. 1 97 

If, however, we look to the races of man as distributed over 
the world, we iiuist infer that their characteristic differences can- 
not be accounted for by the direct action of different conditions 
of life, even after exposure to them for an enormous period of 
time. The Esquimaux live exclusively on animal food ; they are 
clothed in thick fur, and are exposed to intense cold and to 
prolonged darkness; yet they do not differ in any extreme 
degree from the inhabitants of Southern China, who live entirely 
on vegetable food, and are exposed almost naked to a hot, glaring 
climate. The unclothed Fuegians live on the marine produc- 
tions of their inhospitable shores ; the Botocudos of Brazil 
wander about the hot forests of the interior and live chiefly on 
vegetable productions ; yet these tribes resemble each other so 
closely that the Fuegians on board the " Beagle " were mistaken 
by some Brazilians for Botocudos. The Botocudos again, as 
well as the other inhabitants of tropical America, are wholly 
different from the Negroes who inhabit the opposite shores of 
the Atlantic, are exposed to a nearly similar climate, and follow 
nearly the same habits of life. 

Nor can the differences between the races of man be accounted 
for by the inherited effects of the increased or decreased use of 
parts, except to a quite insignificant degree. Men who habitu- 
ally live in canoes, may have their legs somewhat stunted ; 
those who inhabit lofty regions may have their chests enlarged ; 
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. AVith civilised 
nations, the reduced size of the jaws from lessened use — the 
habitual play of different muscles serving to express different 
emotions — and the increased size of the brain from greater 
intellectual activity, have together produced a considerable 
effect on their general appearance when compared with 
savages.*'' Increased bodily stature, without any corresponding 
increase in the size of the brain, may (judging from the pre- 
viously adduced case of rabbits), have given to some races an 
elongated skull of the dolichocephalic type. 

Lastly, the little-understood principle of correlated develop- 
ment has sometimes come into action, as in the case of great 
muscular development and strongly projecting supra-orbital 
ridges. The colour of the skin and hair are plainly correlated, as 
is the texture of the hair with its colour in the INlandans of 
North America.'^** The colour also of the skin, and the odour 

«' See Prof. SchaanTiaiison, trans- ^^ ^\^,^ Catlin states (' N. Ameri- 

lat. in 'Anthropological Keview,' can Indians,' 3rd edit. 1812, vol. I. 
Oct. 1868, p. 429. p. 49) that in the whole tribe of 

198 The Descent of Man. Part 1. 

emitted "by it^ are likewise in some maimer connected. With the 
breeds of sheep the number of hairs within a given space and the 
number of the excretory pores are related.*'^ If we may judge 
from the analogy of our domesticated animals, many modifica- 
tions of structure in man probably come under this principle of 
correlated development. 

We have now seen that the external characteristic differences 
between the races of man cannot be accounted for in a satisfac- 
tory manner by the direct action of the conditions of life, nor by 
the effects of the continued use of parts, nor through the 
principle of correlation. We are therefore led to inquire 
whether slight individual differences, to which man is emi- 
nently 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 this head, none 
of the differences between the races of man are of any direct or 
special service to him. The intellectual and moral or social 
faculties must of course be excepted from this remark. The great 
variability of all the external differences between the races of man, 
likewise indicates that they cannot be of much importance ; for 
■if important, they would long ago have been either fixed and 
preserved, or eliminated. In this resj^ect man resembles those 
forms, called by naturalists protean- or polymorphic, which have 
remained extremely variable, owing, as it seems, to such varia- 
tions being of an indifferent nature, and to their having thus 
escaped the action of natural selection. 

We have thus far been baffled in all our attempts to account 
for the differences between the races of man ; but there remains 
one important agency, namely Sexual Selection, which appears to 
have acted powerfully on man, as on many other animals. I do 
not intend to assert that sexual selection will account for all the 
differences between the races. An unexplained residuum is left, 
about which we can only say, in our ignorance, that as indivi- 
duals are continually born with, for instance, heads a little 
rounder or narrower, and with noses a little longer or shorter, 
such slight differences might become fixed and uniform, if the 

the Maodans, about one in ten or fine and soft. 

twelve of the members, of all ages ®^ On the odour of the skin, 

and both sexes, have bright silvery Godron, ' Sur I'Espece,' torn. ii. p. 

grey hair, wliich is hereditary. 217. On the pores in the skin, 

Now this hair is as coarse and Dr. Wilckens, ' Die Aufgaben der 

harsh as that of a horse's mane, Landwirth. Zootechnik,' 1869, s. 7. 
whilst the hair of other colours is 

Chap. YII. Structure of the Brain. 199 

unknown agencies which induced them were to a^ in a more 
constant manner, aided by long-continued intercrossing. Such 
variations come under the provisional class, alluded to in our 
second chai)ter, which for the want of a better term arc often 
called spontaneous. Nor do I pretend that the etfects of sexual 
selection can be indicated with scientific precision ; but it can bo 
shewn that it would be an inexplicable fact if man had not been 
modified by this agency, which appears to have acted powerfully 
on innumerable animals. It can further be shewn that the 
differences between the races of man, as in colour, hairiness, 
form of features, &c., are of a kind which might have been 
expected to come under the influence of sexual selection. But in 
order to treat this sul»ject i)roperly, I have found it necessary to 
pass the whole animal kingdom in review. I have therefore 
devoted to it the Second Part of this work. At the close I shall 
return to man, and, after attempting to shew how far he has 
been modified through sexual selection, will give a brief summary 
of the chapters in this First Part. 

Note ox the Resemblances and Differences in the Structure 
AND THE Development of the Brain in Man and Apes. By 
Professor Huxlev, F.R.S. 

The controversy respecting the nature and the extent of the differ- 
ences in the slructme of the brain in man and the apes, which arose 
some fifteen years ago, has not yet come to an end, though the subject 
matter of the dispute is, at present, totally different fronr what it was 
formerly. It was originally asserted and re-asserted, with singular 
pertinacity, that the biain of all the apes, even the highest, differs from 
that of man, in the absence of such conspicuous structures as the 
posterior lobes of the cerebral licmifepheres, with the posterior cornu of 
the lateral ventricle and the hi ppocampus minor, contained in those 
lobes, which are so obvious in man. 

But the truth that tlie three structm-es in question are as well deve- 
loped in apes' as in human brains, or even b. ttei ; and that it is character- 
istic of all the rrhnaits (if we exclude the Lennu's) to have these parts 
well developed, stands at present on as secure a basis as any profiosition 
in comparative anatomy. Moreover, it is admitted by every one of the 
long series of anatomihts who, of late years, have paid special attention to 
the arrangtment of the complicated sulci and gyri which sippcar up;in 
the surface of the cerebral hemispheres in man and the higher ape-', 
that ihey are di?posed after the very same pattern in him, a> in them. 
Every principal gyrus and sulcus of a chim])anzee's bram is ( h arly 
rcpiesentLd in that of a man, so that the terminology which ajjpHcs to 
the one answers lor the other. On this point there is no ditlVrenrc of 
opinion. Some years since, Professor Bischoff published a memoir '" on 
the C('rebral convolutions of man and apes; and as the ptupnse of 
my learned colleague was certainly not to diminish the value of the 

*" 'Die Gi'osshirn-Wmdungen des Menschen ;' ' AbhaQJluugea dev K, 
Bayerischeu Akademie.* Bd. x., 18G8. 

200 • The Descent of Man. Part 1. 

differences between apes and men in this respect, I am glad to make a 
citation from him. 

" That the apes, and especially the orang, chimpanzee and gorilla, 
" come very close to man in their organisation, much nearer than to any 
" otlier animal, is a well known fact, disputed by nobody. Looking at 
" the matter from the point of view of organisation alone, no one probably 
" would ever have disputed Ihe view of Linnaeus, that man should be 
" placed, merely as a peculiar species, at the hs ad of the mammalia and of 
*' those apes. Both shew, in all their organs, so close an affinity, that the 
" most exact anatomical investigation is needed in order to demonstrate 
" those differences which really exist. So it is with the brains. The 
" brains of man, the orang, the chimpanzee, the gorilla, in spite of all 
'' the important differences which they present, cume very close to one 
" another ' (1. c. p. 101). 

Tiiere remains, then, no dispute as to the resemblance in fundamental 
characters, between the ape's brain and man's ; nor any as to the won- 
derfully close similarity between the chimpanzee, orang and man, in 
even the details of the arrangement of the gyri and sulci of the cerebral 
hemispheres. Nor, turning to the differences between the brains of 
the highest apes and that of man, is there any serious question as to 
the nature and extent of these differences. It is admitted that the man's 
cerebral hemispheres are absolutely and relatively larger than those of 
the orang and chimpanzee ; that his frontal lobes are less excavated by 
the upward protrusion of the roof of the orbits ; that his gyri and sulci 
are. as a rule, less symmetrically disposed, and present a greater num^jer 
of secondary plications. And it is admitted that, as a rule, in man, the 
temporo-occipital or "external perpendicular" fissure, which is usually 
so strongly marked a feature of the ape's brain is but faintly marked. 
But it is also clear, that none of these differences constitutes a sharp 
demarcation between the man's and the ape's brain. In respect to the 
external perpendicular fissure of Gratiolet, in the human brain, for 
instance. Professor Turner remarks :'^ 

" In some brains it appears simply as an indentation of the margin of 
" the hemisphere, but, in others, it extends for some distance more or less 
" transversely outwards. I saw it in the right hemisphere of a female 
" brain pass more than two inches outwards ; and in another specimen, 
" also the right hemisphere, it proceeded for four-tenths of an inch out- 
" wards, and then extended downwards, as far as the lower margin of the 
" outer smface of the hemisphere. The imperfect definition of this fissure 
" in the majority of human brains, as compared with its remarkable dis- 
" tinctness in the brain of most Quadrumana, is owing to the presence, in 
" the former, of certain superficial, well marked, secondary convolutions 
" which bridge it over and connect the parietal with the occipital lobe. 
" The closer the first of these bridging gyri lies to the longitudinal 
" fissure, the shorter is the external parieto-occipital fissure." (1. c p. 12.) 

The obliteration of the external perpendicular fissure of Gratiolet, 
therefore, is not a constant character of the human brain. On the other 
hand, its full development is not a. constant character of the higher 
ape's brain. For, in the chimpanzee, the more or less extensive oblitera- 
tion of the exteraal perpt-mUeular sulcus by " bridging convolutions," on 
one side or the other, has been noted over and over again bv Prof 

'* 'Convolutions of the Human Cerebrum Topographically Considered, 
1866, p. 12. 

Chap. VII. Siriictiire of the Brain. 20 1 

Rolleston, Mr. Marshall, -M. Brora and Professor 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 generalisation which Gratiolet has attempted to draw of 
" the complete absence of the first ccmnecting convolution and the 
" concealment of the second, as essentially characteristic features in th(; 
" brain of this animal, is by no means universally applicable. In only one 
" specimen did the brain, in these particulars, follow the law which 
" Gratiolet has expressed. As regards the presence of the su])eriur britlg- 
" ing convolution, I am inclined to think that it has existed in one hemi- 
" sphere, at least, in a majority of the brains of this animal which have, up 
" to this time, been figured or described. The superficial position of the 
" second bridging convolution is evidently less frequent, and has as yet, 
•' I believe, only been seen in the brain (A) recorded in this communi- 
" cation. The asymmetrical arrangement in the convolutions of the 
" two hemispheres, which previous observers have referred to in their 
" descriptions is also well illustrated in these specimens." (pp. 8, 9.) 

Even were the presence of the temporo-occipital, or external per- 
pendicular, sulcus a mark of distinction between the higher apes an 1 
man, the value of such a distinctive character would be rendered very 
doubtful by the structure of the brain in the Piatyrhine apes. In fact 
wliile the temporo-occipital is one of the most con.-itant of sulci in 
the Catarhine, or Old World, apes, it is never very strongly developed 
in the New World apes ; it is absent in the smaller Platyrhini ; 
rudimentary in Tithecia ;" and more or less obliterated by bridging 
convolutions in Ateles. 

A character which is thus variable within the limits of a single group 
cfin have no great taxouomic value. 

It is further established, that the degree of asymmetry of the convolu- 
tion of the two sides in the human brain is subject to nnieh individual 
variation,; and that, in those individuals of the Bushman race who have 
been examined, the gyri and sulci of the two hemispheres are consider- 
ably less complicated and more symmetrical than in the European 
brain, while, in some individuals of the chimpanzee, their complexity 
and asymmetiy become notable. This is particularly tlie case in the 
brain of a young male chimpanzee figured by M. Broca. (' Lorch-e 
des Primates," p. 165, fig. 11.) 

Again, as respects the question of absolute size, it is established that 
the difterence between the largest and the smallest healtiiy human 
brain is greater than the ditference between the smallest healthy 
human brain and the largest chimpanzees or orang's brain. 

Moreover, there is one circumstance in which the orang's and chim- 
panzee's brains resemble man's, but in which they ditter from the lower 
apes, and that is the presence of two corpora candicantia — the 
t'ynomorpha having but one. 

In view of these facts I do not hesitate in this year 1874, to repeat 
and insist upon the proptjsition which I inundated in ISGS.^'' 

" So far as cerebral structure goes, therefore, it is clear that man 

" Notes more especially on the " Flower 'On the Anatomy of 

bridging convolutions in the Brain I'ithecia Monackns,'' ' I'roceedings of 

of the Chimpanzee, 'Proceedings of the 2lk)ol<)gical Society,' 18G2. 

the Royal Society of Edinburgh,' '* ' Man's Place in Nature,' p. 102. 


202 The Descent of Man. Part L 

" diffirs less from the chimpanzee or the orang, than these do even 
"from the monkeys, and that the diflference between the brain of the 
"•chimpanzee and of man is almost insignificant, when compared with 
"that between the chimpanzee brain and that of a Lemur." 

In the paper to which I have referred, Professor Bischofif does not 
deny tlie second part of this statement, but he first makes the irrelevant 
remark that it is not wonderful if the brains of an orang and a Lemur 
are very different ; and secondly, goes on to assert that, " If we succes- 
" sively compare the brain of a man with that of an orang ; the brain of 
" this with that of a chimpanzee ; of this with that of a "orilla, and so 
"on of a Hylobates, Semnopithecus, Cynocephalus, Cercopithecus, Macacus, 
" Cehus, Callithrix, Lemur, Stenops, Hapale, we shall not meet with a 
" greater, or even as great a, break in the degree of development of the 
"convolutions, as we find between the brain of a man and that of au 
" orang or chimpanzee." 

To which I reply, firstly, that whether this assertion be true 
or false, it has nothing whatever to do with the proposition enunciated 
in 'Man's Place in Nature,' which refers not to the development of the 
convolutions alone, but to the structure of the whole brain. It Professor 
Bischoff had taken the trouble to refer to p. 96 of the work he criticises, 
in fact, he would have found the following passage: "And it is a 
" remarkable circumstance that though, so far as our present know- ■ 
" ledge extends, there is one true structural break in the series of forms 
" of Simian brains, this hiatus does not lie between man and the 
" manlike apes, but between the lower and the lowest Simians, or in 
" other words, between the Old and New World apes and monkeys and 
" the Lemurs. Every Lemur which has yet been examined, in fact, 
" has its cerebellum partially visible from above; and its posterior lobe, 
" with the contained posterior cornu and hippocampus minor, moie or 
"less rudimentary. Every marmoset, American monkey, Old World 
" monkey, baboon, or manlike ape, on the contrary, 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 w^as known 
when it was made; and it does not appear to me to be more than 
apparently weakened by the subsequent discovery of the relatively 
small development of the posterior lobes in the Siamang and in the 
Howling monkey. Notwithstanding the exceptional brevity of the 
posterior lobes in these two species, no one will pretend that their 
brains, in the slightest degree, approach those of the Lemurs. And 
if, instead of putting Hapale out of its natural place, as Professor 
Bischoff most unaccountably does, we write the series of animals 
he has chosen to mention as follows : Homo, Pithecus, Troglodytes, 
Hylobates, Semnopithecus, Cynocephalus, CercopWieeus, Macacus, Cebus, 
Callithrix, Hapale, Lemur, Stenops, I venture to reaffirm that the 
great break in this series lies between Hapale and Lemur, and that 
tills break is considerably greater than that between any other two 
terms of that series. Professor Bischoff" ignores the fact that long 
before he wrote, Gratiolet had suggested the separation of the Lemurs 
from the other Primates on the very ground of the difference in their 
cerebral characters ; and that Professor Flower had made the following 
observations in the course of his description of the brain of the Javan 
Lor is J ^ 

'^ 'Transactions of the Zoological Society,' vol. v. 1862. 

(JHAP. VII. Structure of the Brain. 203 

"And it is especially remarkable that, in the development of the 
" posterior lobes, there is no approximation to the Leinurine, short 
"hemisphered, brain, in those monkeys which are commonly supposed 
'• to approach this family in other respects, viz., the lower members of 
" tlie Fiatyrhine gronp." 

So far as the structure of the adult brain is concerned, then, the very 
considerable additions to oar knowledge, which have been made by the 
researches of so many investigators, during tlie past ten years, fully 
justify the statement which I made in 1SG3. But it has been said 
that, admitting the similarity between the adult brains of man and 
apes, they are nevertheless, in reality, widely diiFerent, because th( y 
exhibit fundamental dilierences in the mode of their development. No 
one would be more ready tlian I to admit the force of this argument, if 
8uch fundamental diiierenccs of development really exist, liut I deny 
that they do exist. On the contrary, there is a fundamental agree- 
ment in the developmeut of the brain in men and apes. 

Gratiolet originated the statement that there is a fundamental 
difference in the development of the brains of apes and that of man — 
consisting in this; that, in the apes, the sulci which first make their 
appearance are situated on the posterior region of the cerebral hemi- 
spheres, while, in the liuman foatus, 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 be born, in which the posterior gyri were " well 
" developed," while those of the frontal lobes were'* hardly indicated "''" 
(1. c. p. 39), and the other of a human foetus at the 22nd or 23rd week 
of uterogestation, in which Gratiolet notes that the insula was un- 
covered, but that nevertheless " des incisures sement le lobe anterieur, 
" une scissure pen profonde indique la separation du lobe occipital, tres- 

'' " Chez tous les singes, les plis Rolando, and one of the frontal 

" posterieurs se developpent les pre- sulci, plainly enough. Nevertheless, 

*' miers ; les plis anterieurs se M. Alix, in his ' Xotice sur les 

" developpent plus tard, aussi la travaux anthropologiques de Gratio- 

*' vert^bre occipitale et la parietale let ' (Mem. de la Societe d'Anthro- 

**sont-ellesrelativemeuttres-grandes pologie de Paris,' 1868, p. xxxii.), 

" chez le foetus. L'Horame presente writes thus : " Gratiolet a eu outre 

*' une exception remarquable quant " les mains le cerveau d'un fa>tus de 

" i I'epoque de Tapparitioa des plis " Gibbon, singe emiuemment su- 

" frontaux, qui sont les premiers " perieur, et tellement rapproche de 

*' indiquus ; niais le developpement " I'orang, que des naturalistes tres- 

*• general du lobe frontal, envisage " competeuts I'ont range parmi les 

" seulement par rapport a son " anthropoides. M. Huxley, par ex- 

*' volume, suit les memeslois que dans " emple, u'hesite pas sur ce point. 

" les singes :" Gratiolet, ' Memoire " Eh bien, c'est sur le cerveau d'un 

sur les plis cerebraux de I'Homme *' foetus de Gibbon que Gratiolet a 

et des Primates,' p. 39, tab. iv. " vu les circonvolutiuns du lobe tem- 

fig. 3. " poro-Sfjhenoidal deja deceloppecs 

'''' Gratiolet's words are (1. c. p. '■'■ lorsqu'il n existent pas encore de plis 

39): "Dans le foetus don t 11 s'agit " s/^r le lobe frontal. II etait done 

" les plis cerebraux posterieurs sont " bien autorise a dire que, cliez 

" bien developpes, tandis que les " I'homme les circonvolutious aj)pa- 

" plis du lobe frontal sont i peine " raissent d'a eu w, tandis que chez 

" indiques." The figure, however " les singes elles se developpent 

(PI. iv. fig. 3), shews the fissure of " d'w en a." 

204 The Descent of Man. Part I. 

" rediiit, d'ailleurs des cctte epoque. Le reste de la siuface cerebrale 
" eit encore absolument lisse." 

Three views of this brain are given in Plate 11. figs, 1, 2, 3, of the 
work cited, shewing the upper, lateral and inferior views of the hemi- 
spheres, but not the inner view. It is worthy of note that the figure 
by no means bears out Gratiolet's description, inasmuch as tlie fissure 
(anterotempoi al) on the posterior half of the face of the hemisphere, is 
more marked than any of those vaguely indicated in the anterior half. 
If the figure is correct it in no way justifies Gratiolet's conclusion : 
" II y a done entre ces cerveaux [those of a Callithrix and of a Gibbon] et 
" celui du foetus humain une ditierence fondamental. Chez celui-ci, long- 
" temps 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, Bischoft', 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 resiilts of their inquiries may b© summed up as follows : — 

1. In the human foetus, the sylvian fissure is formed in the course of 
the third month of uterogestation. In this, and in the fourth month, 
the cerebral hemispheres are smooth and rounded (with the exception 
of the sylvian depression), and they project backwards far beyond the 

2. The sulci, properly so called, begin to appear in the interval 
between the end of the fourth and the beginning of the sixth month of 
foetal life, but Ecker is careful to point out that, not only the time, but 
the order, of their appearance is subject to considerable individual 
variation. In no case, however, are either the frontal or the temporal 
sulci the earliest. 

The fir;.t which appears, in fact, lies on the inner face of the hemi- 
sphere (whence doubtless Gratiolet, who does not seem to have examined 
that face in his foetus, overlooked it), and is either the internal perpen- 
dicular (occipito-parietal), or the calcarine sulcus, these two being close 
together and. eventually running into one another. As a rule the 
occipito-parietal is the earlier of the two. 

3. At the latter part of this period, another sulcus, the " posterio, 
parietal," or " Fissure of Rolando "' is developed, and it is followed, in 
the course of the sixth month, by the other principal sulci of the 
fiontal, parietal, tempoial and occipital lobes. There is, however, no 
clear evidence that one of these constantly appears before the otlier; 
and it is remarkable that, in the brain at the period described and 
figured by Ecker (I. c. p. 212-13, Taf. II. figs. 1, 2, 3, 4), the antero- 
temporal sulcus {scissure parallele) so characteristic of the ape's brain, 
IS as well, if not better developed than the fissure of llolando, and is 
much more marked than the proper frontal sulci. 

Taking the facts as they now stand, it appears to me that the order 
of the appearance of the sulci and gyri in the foetal human brain is iu 
perfect harmony with the general tloctrine of evolution, and with the 

'* ' Ueber die typische Anordnung ^^ ' Zur Entwickelungs Geschichte 

der Furchen und Windungea auf der Furchen und Windungen der 

den Grosshirn-Hemispharen des Grosshirn-Hemispharen im Foetus 

Menschen und der Aften.' 'Archiv des MeHschen.' ' Archiv fiir Anthro- 

fiir Anthropologie,' iii., 1868. pologie,' iii., 1868. 

Chap. Y 1 1. StructtLve of tJie Brain. 205 

view that man has been evolved from some ape- like form ; though there 
can be no doubt that that form was, in many respects, ditieient from 
any member of the Frimates now living. 

Von Buer 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 
ituimal is precisely similar to the adult condition of any lower animal, 
it is quite correct to say that a frog passes through the condition of a 
fish, inasmuch as at one period of its life the tadpole has all the cha- 
racters of a fish, and, if it went no further, would have to be grouped 
among fishes. But it is equally true that a tadpole is very different 
from any known fish. 

In like manner, the brain of a human foetus, at the fifth month, may 
correctly be said to be, not only the braiu of an ape, but that of a:i 
Arctopitheciue or marmoset-like ape ; for its hemispheres, with their 
great posterior lobster, and with no sulci but the sylvian and the 
calcarine, present the characteristics found only in the group of the 
Arctopilhecine Primates. But it is equally true, as Gratiolet remarks, 
that, in its widely open sylvian fissure, it differs from the biain 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 Cehus Apella, in addition to 
the sylvian fissure and the deep calcarine fissure, only a very shallow 
anterotemporal fissure (sc/ssare parallele of Gratiolet.) 

Now this fact, taken together with the circumstance that the antnro- 
temporal sulcus is present in such Platyrhini as the Saimiri, which 
present mere traces of sulci on the anterior half of the exterior of the 
cerebral hemispheres, or none at all, undoubtedly, so far as it goes, 
affords fair evidence in favour of Graliolet's hypothesis, that the 
])osterior sulci appear before the anterior, in the brains of the 
riatyrldui. But, it by no means follows, that the rule which may hold 
good for the PlatyrJuni extends to the Catarhini. We have no in- 
formation whatever respecting the development of the brain in the 
Cyiunnorpha; and, as regards the Anthropomorplta, nothing but the 
account of the brain of the Gibbon, near biitli, already referred to. 
At the present moment, there is not a shadow of evidence to shew 
that the sulci of a chiiupanzee's, or orang's, brain do not appear in the 
same order as a man's. 

Gratiolet opens his preface with the aphorism. " II est dangereux 
" dans les sciences de conclure trop vite." I fear he must have for- 
goiten 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 been 
made, would have been the first to admit the insufficiency of his data 
had he lived to profit by the advance of inquiry. The misfortune is 
tliat his conclusions have been employed by persons incompetent to 
appreciate their foundation, as arguments in favour of obscurantism." 

*" For example, !M. I'Abbe Lecomte winisme et I'origine de THomme. 
ia his terrible pamphlet ' Le Dar- 1873. 

2o6 T]ie Descent of Man. Part I. 

But it is important to remark that, whether Gratiolet was right or 
wrong in- his hypothesis respecting the relative order of appeaiance of 
the temporal and frontal sulci, the fact remains ; that, before either 
temj)oral 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 shouLl 
expect to be the case, if man has resulted from the gradual modifica- 
tion of the same form as that from which the other Primates have 

( 207 ) 

Part LL 


Principles of Sexual Selection. 

Secondary sexual characters — Sexual selection — Manner of action— Ex- 
cess of males — Polygamy — The male alone generally modified through 
sexual selection — Eagerness of the male — Variability of the male — 
Choice exerted by the female — Sexual compared with natural selection 
— Inheritance, at corresponding periods of life, at corresponding seasons 
of the year, and as limited by sex — Relations between the several forms 
of inheritance — Causes why one sex and the young are not modified 
through sexual selection — Supplement on the proportional numbers of 
the two sexes throughout the animal kingdom — The proportion of the 
sexes in i-elation 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 charac- 
ters, which are not directly connected with the act of reproduc- 
tion ; for instance, the male possesses certain organs of sense or 
locomotion, of which the female is quite destitute, or has them 
more highly-developed, in order that he may readily find or 
reach her ; or again the male has special organs of prehension for 
holding her securely. These latter organs, of infinitely diversified 
kinds, graduate into those which are commonly ranked as 
primary, and in some cases can hardly be distinguished from 
them ; we see instances of this in the complex appendages at the 
apex of the abdomen in male insects. Unless indeed we confine 
the term "primary" to the reproductive glands, it is scarcely 
possible to decide which ought to be called primary and which 

The female often differs from tlie male in having organs for the 
nourishment or protection of her young, such as the mammary 

2o8 The Descent of Man. Part II. 

glands of mammals, and tlie abdominal sacks of the marsupials. 
In some few cases also the male possesses similar organs, which 
are wanting in the female, snch as the receptacles for the 
ova in certain male fishes, and those temporarily deyeloped in 
certain male frogs. The females of most bees are provided with 
a special apparatus for collecting and carrying pollen, and their 
ovipositor is modified into a sting for the defence of the larvae 
and the community. Many similar cases could be given, but 
they do not here concern us. There are, however, other sexual 
differences quite unconnected with the primary reproductive 
organs, and it with is these that we are more especially concerned 
— such as the greater size, strength, and pugnacity of the male, 
his weapons of offence or means of defence against rivals, his 
gaudy colouring and various ornaments, his power of song, and 
other such characters. 

Besides the primary and secondary sexual differences, such as 
the foregoing, the males and females of some animals differ in 
structures related to different habits of life, and not at all, or 
only indirectly, to the reproductive functions. Thus the females 
of certain flies (Cuhcidse and Tabanidse) are blood-suckers, 
whilst the males, living on flowers, have mouths destitute of 
mandibles.^ The males of certain moths and of some crustaceans 
(e. (J. Tanais) have imperfect, closed mouths, and cannot feed. 
The complemeutal males of certain Cirripedes live like epiphytic 
plants either on the female or the hermaphrodite form, and are 
destitute of a mouth and of prehensile limbs. In these cases it is 
the male which has been modified, and has lost certain important 
organs, which the females possess. In other cases it is the female 
which has lost such parts; for instance, the female glow- worm is 
destitute of wings, as also are many female moths, some of which 
never leave theii- cocoons. Many female parasitic crustaceans 
have lost their natatory legs. In some weevil-beetles (Curcu- 
lionidse) 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 wonderfully great, and we hear from Dr. Duller ^ 

^ Westwood, 'Modern Class, of - Kirby and Spence, ' Introduc- 

Insects,' vol. ii. 1840, p. 541. For tion to Entomology,' vol. iii. 1826, 

the statement about Tanais, men- p. 309. 

tioned below, I am indebted to Fritz ^ ' Bii^jg ^f New Zealand,' 1872, 

Miiller. p. 66. 

Chap. VIII. Sexual Selection. 209 

that the male uses his strong beak in chiselling the larvre of 
insects out of decayed wood, whilst the female probes the softer 
parts with her far longer, much curved and pliant beak : and 
thus they mutually aid each other. In most cases, differences of 
structure between the sexes are more or less directly connected 
with the propagation of the species : thus a female, which has to 
nourish a multitude of ova, requires more food than the male, 
and consequently requires special means for procuring it. A male 
animal, which lives for a very short time, might lose its organs 
for procuring food through disuse, without detriment ; but he 
would retain his locomotive organs in a perfect state, so that 
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 

We are, however, here concerned only with sexual selection. 
This depends on the advantage which certain individuals have 
over others of the same sex and species solely in respect of 
reproduction. When, as in the cases above mentioned, the two 
sexes differ in structure in relation to different habits of life, 
they have no doubt been modified through natural selection, and 
by inheritance limited to one and the same sex. So again the 
primary sexual organs, and those for nourishing or protecting the 
young, come under the same influence ; for those individuals which 
generated or nourished their offspring best, would leave, cctteris 
paribus, the greatest number to inherit their superiority ; whilst 
those which generated or nourished their offspring badly, would 
leave but few to inherit their weaker powers. As the male has to 
find the female, he requires organs of sense and locomotion, 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 antennae modified in an extraordinary manner for the . 
prehension of the female ; hence we may suspect that it is be- 
cause these animals are washed about by the waves of the 
open sea, that they require these organs in order to propagate 
their kind, and if so, their development has been the result of 
ordinary or natural selection. Some animals extremely low in 
the scale have been modified for this same purpose ; thus the 
males of certain parasitic worms, when fully grown, have the 
lower surface of the terminal part of their bodies roughened 

2 lo The Descent of Alan. Pakt II, 

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 highly 
developed than those of the female, it may be that the perfection 
of these is indispensable to the male for finding the female ; but 
in the vast majority of cases, they serve only to give one male 
an advantage over another, for with sufficient time, the less well- 
endowed males would succeed in pairing with the females ; and 
judging from the structure of the female, they would be in all 
other respects equally well adapted for their ordinary habits of 
life. Since in such cases the males have acquired their present 
structure, not from being better fitted to survive in the struggle 
for existence, but from having gained an advantage over other 
males, and from having transmitted this advantage to their male 
offspring alone, sexual selection must here have come into action. 
It was the importance of this distinction which led me to 
designate this form of selection as Sexual Selection. So again, 
if the chief service rendered to the male by his prehensile organs 
is to prevent the escape of the female before the arrival of other 
males, or when assaulted by them, these organs '^ill have been 
perfected through sexual selection, that is by the advantage 
acquired by certain individuals over their rivals. But in most 
cases of this kind it is impossible to distinguish between the 
effects of natural and sexual selection. Whole chapters could 
be filled with details on the differences between the sexes in their 
sensory, locomotive, and prehensile organs. As, however, these 
structures are not more interesting than others adapted for the 
ordinary purposes of life I shall pass them over almost entirely, 
giving only a few instances under each class. 

There are many other structures and instincts which must 
have been developed through sexual selection— such as the 
weapons of offence and the means of defence of the males for 
fighting with and driving away their rivals— their courage and 
pugnacity — their various ornaments — their contrivances for pro- 

* M. Perrier advances this case claspers of certain male animals 
('Revue Scientifique,' Feb. 1, 1873, could not have been developed 
p. 865) as one fatal to the belief in through the choice of the female I 
sexual selection, inasmuch as he Had J not met with this remark, I 
supposes that I attribute all the should not have thought it possible 
differences between the sexes to for any one to have read this chapter 
sexual selection. This distinguished and to have imagined that I main- 
naturalist, therefore, like so many tain that the choice of the female 
other Frenchmen, has not taken the had anything to do with the develop- 
trouble to understand even the first meut of the prehensile organs in the 
principles of sexual selection. An male. 
English naturalist insists that the 

Chap. VII r. Sexual Selection. 211 

duciiig vocal or instrumental music — and their glands for 
emitting odours, most of these latter structures serving only to 
allure or excite the female. It is clear that these characters are 
the result of sexual and not of ordinary selection, since unarmed, 
unornamented, or unattractive males would succeed equally well 
in the battle for life and in leaving a numerous jDrogeny, but for 
the presence of better endowed males. We may infer that this 
would be the case, because the females, which arc 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 ot either sex. When we 
behold two males fighting for the possession of the female, or 
several male birds displaying their gorgeous plumage, and per- 
forming strange antics before an assembled body of females, we 
cannot doubt that, though led by instinct, they know what they 
are about, and consciously exert then' mental and bodily powers. 

Just as man can improve the breed of his game-cocks by the 
selection of those birds which are victorious in the cockpit, so it 
appears that the strongest and most vigorous males, or those 
provided with the best weapons, have prevailed under nature, 
and have led to the improvement of the natural breed or species. 
A slight degree of variability leading to some advantage, how- 
ever slight, in reiterated deadly contests would suffice for the 
work of sexual selection; and it is certain that secondary sexual 
characters are eminently variable. Just as man can give beauty, 
according to his standard of taste, to his male poultry, or more 
strictly can modify the beauty originally acquired by the parent 
species, can give to the Sebright bantam a new and elegant 
plumage, an erect and peculiar carriage— so it appears that 
female bii'ds in a state of nature, have by a long selection of the 
more attractive males, added to their beauty or other attractive 
quahties. No doubt this implies powers of discrimination and 
taste on the part of the female wliich will at first appear 
extremely improbable; but by the facts to be adduced here- 
after, I hope to be able to shew that the females actually 
have these powers. When, however, it is said that the lower 
animals have a sense of beauty, it must not be supposed that 
such sense is comparable with that of a cultivated man, with his 
multiform and complex associated ideas. A more just com- 
parison would be between the taste for the beautiful in animals, 
and that in the lowest savages, who admire and deck themselves 
with any brilliant, glittering, or curious object. 

From our ignorance on several points, the precise manner in 

212 The Descent of Man. Part IL 

which sexual selection acts is somewhat "uncertain. Neverthe- 
less if those naturalists who already believe in the mutability of 
species, will read the following chapters, they will, I think, agree 
with me, that sexual selection has played an important part in 
the history of the organic world. It is certain that amongst 
almost all animals there is a struggle between the males for the 
possession of the female. This fact is so notorious that it would 
be superfluous to give instances, Hence the females have the 
opportunity of selecting one out of several males, on the suppo- 
sition that their mental capacity suffices for the exertion of a 
choice. In many cases special circumstances tend to make the 
struggle between the males particularly severe. Thus the males 
of our migratory birds generally arrive at their places of breeding 
before the females, so that many males are ready to contend for 
each female. I am informed by Mr. Jenner Weir, that the bird- 
catchers assert that this is invariably the case with the nightin- 
gale and blackcap, and with respect to the latter he can himself 
confirm the statement. 

Mr. Swaysland of Brighton has been in the habit, during the 
last forty years, of catching our migratory birds on their first 
arrival, and he has never known the females of any species to 
arrive before their males. During one spring he shot thirty -nine 
males of Eay's wagtail {Budytes Rail) before he saw a single 
female. Mr. Gould has ascertained by the dissection of those 
snipes which arrive the first in this country, that the males come 
before the females. And the like holds good with most of the 
migratory birds of the United States.^ The majority of the male 
salmon in our rivers, on coming up from the sea, are ready to 
breed before the females. So it appears to be with frogs and 
toads. Throughout the great class of insects the males almost 
always are the first to emerge from the pupal state, so that they 
generally abound for a time before any females can be seen.*^ 
The cause of tliis 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 
T\^hich in the spring were first ready to breed, or were the most 
eager, would leave the largest number of ofl"spring ; and these 

' J. A. Allen, on the 'Mammals rodite plants are dichogamous ; that 

and Winter Birds of Florida,' Bull. is, their male and female organs are 

Comp. Zoology, Harvard College, p. not ready at the same time, so that 

268. they cannot be self-fertilised. Now 

^ Even with those plants in which in such flowers, the pollen is in 

the sexes are separate, the male general matured before the stigma, 

flowers are generally mature be- though there are exceptional cases 

fore the fernale. As first shewn in Avhich the female organs are 

by C. K. Sprengel, many hermaph- beforehaad. 

Chap. VIII. Sexual Selection. 213 

would tend to inherit similar instincts and constitutions. It 
must be borne in mind that it would have been impossible to 
change very materially the time of sexual maturity in the 
females, without at the same time interfering with the period of 
the production of the young— a period which must bo determined 
by the seasons of the year. On the whole there can be no doubt 
that with almost all animals, in which the sexes are separate, 
there is a constantly recurrent struggle between the males for 
the possession of the females. 

Our difficulty in regard to sexual selection lies in understand- 
ing how it is that the males which conquer other males, or those 
which prove the most attractive to the females, leave a greater 
number of offspring to inherit their superiority than their 
beaten and less attractive rivals. Unless this result does follow, 
the charactei-s 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 
vrorst-endowed males will (except where polygamy prevails), 
ultimately find females, and leave as many offspring, as well 
fitted for theu' 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 
beheve 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 ]\Ir. Jenncr Weir, 
who hasT^arefully attended to the habits of birds during many 
years. There can also be no doubt that the most vigorous, 
best-nourished and earhest 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 

* Here is excellent evidence on an experienced ornithologist. Mr. 
the character of the ofispring from J. A. Allen, in speaking ('Mammals 

214 The Descent of Man. Part I L 

females ; the strongest, and with some species the best armed of 
the males, drive away the weaker ; and the former would then 
unite with the more vigorous and better-nourished females, be- 
cause they are the first to breed.^ Such vigorous pairs would 
surely rear a larger number of offspring than the retarded 
females, which would be compelled to unite with the conquered 
and less powerful males, supposing the sexes to be numerically 
equal ; and this is all that is wanted to add, in the course of 
successive generations, to the size, strength and courage of the 
males, or to improve their weajDons. 

But in very many cases the males which conquer their rivals, 
do not obtain possession of the females, independently of the 
choice of the latter. The courtship of animals is by no means 
so simple and short an affair as might be thought. The 
females are most excited by, or prefer pairing with, the more 
ornamented males, or those which are the best songsters, or play 
the best antics; but it is obviously probable that they would 
at the same time prefer the more vigorous and lively males, and 
this has in. some cases been confirmed by actual observation.^ 
Thus the more vigorous females, which are the first to breed, will 
have the choice of many males ; and though they may not always 
select the strongest or best armed, they will select those which 
are vigorous and well armed, and in other respects the most at- 
tractive. Both sexes, therefore, of such early pairs would as above 
explained, have an advantage over others in rearing offspring ; and 
this apparently has suflficed during a long course of generations 
to add not only to the strength and fighting powers of the males, 
but Hkewise to their various ornaments or other attractions. 

In the converse and much rarer case of the males selecting 
particular females, it is plain that those which were the most 
vigorous and had conquered others, would have the freest 
choice ; and it is almost certain that they would select vigorous 
as well as attractive females. Such pairs would have an advan- 

and Winter Birds of E. Florida,' to those female bees which are the 

p. 229) of the later broods, after the first to emerge from the puj^a each 

accidental destruction of the first, year. See his remarkable essaj-, 

bays, that these " are found to be 'Anwendung den Darwin'schen Lehra 

" smaller and paler-coloured than auf Bienen,' ' Verh. d. ^ . Jahrg.' 

" those hatched earlier in the sea- xxix. p. 45. 

*' son. In cases where several broods ^ With respect to poultry, I have 

" are reared each year, as a general received information, hereafter to 

" rule the birds of the earlier broods be given, to this effect. Even with 

" seem iji all respects the most per- birds, such as pigeons, which pair 

*' feet and vigorous." for life, the female, as I hear from 

^ Hermann Miiller has come to Mr. Jenner Weir, will desert her 

this same conclusion with respect mate if he is injured or grows weak. 

Uh.\ 1'. VIII. Scxnal Selection. 2 1 5 

tage in rearing offspring, more especially if the male had the 
power to defend the female during the pairing-season as occurs 
with some of the higher animals, or aided her in providing for 
the young. The same principles would apply if each sex pre- 
ferred 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 con- 
siderably more numerous than the females. Hence I was led to 
investigate, as far as I could, the proportions between the two 
sexes of as many animals as possible; but the materials are 
scanty. I will here give only a brief abstract of the results, 
retaining the details for a sujiplementary discussion, so as not 
to interfere with the course of my argument. Domesticated 
animals alone afford the means of ascertaining the propor- 
tional numbers at birth; but no records have been specially 
kept for this purpose. By indirect means, however, I have 
collected a considerable body of statistics, from which it appears 
that with most of our domestic animals the sexes are nearly 
equal at birth. Thus 25,560 births of race-horses have been 
recorded during twenty-one years, and the male births were 
to the female births as 99"7 to 100. In greyhounds the in- 
equality is greater than with any other animal, for out of 6878 
births dui-ing twelve* years, the male births were to the female 
as 110-1 to 100. It is, however, in some degree doubtful 
whether it is safe to infer that the proportion would be the same 
under natural conditions as under domestication ; for slight and 
unknown differences in the conditions affect the proi^ortion of 
the sexes. Thus with mankind, the male births in England 
are as 101'5, 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 Euroj^ean 
extraction have been born during several years in the proportion 
of between 90 and 99 to 100 female children. 

For our present purpose we are concerned with the proportion 
of the sexes, not only at birth, but also at maturity, and this 
adds another element of doubt ; for it is a well-ascertained fact 
that with man the number of males dying before or during birth, 
and during the first few years of infancy, is considerably larger 
than that of females. So it almost certainly is with male lambs, 
and probably with some other animals. The males of some species 
kill one another by fighting ; or they drive one another about 

2 1 6 The Descent of Man. Tart II. 

until they become greatly emaciated. Tliey must also be often 
exposed to yarious dangers, whilst wandering about in eager 
search for the females. In many kinds of fish the males are- 
much smaller than the females, and they are beheved often to be 
devoured by the latter, or by other fishes. The females of 
some birds appear to die earlier than the males; they are 
also liable to be destroyed on their nests, or whilst in cliarge 
of their young. With insects the female laryse are often larger 
than those of the males, and w^ould consequently be more likely 
to be. devoured. In some cases the mature females are less 
active and less rapid in their movements than the males, and 
could not escape so well from danger. Hence, with animals in a 
state of nature, wo must rely on mere estimation, in order to 
judge of the proportions of the sexes at maturity ; and this is 
but little trustworthy, except when the inequality is strongly 
marked. Nevertheless, as far as a judgment can be formed, we 
may conclude from the facts given in the supplement, that the 
males of some few mammals, of many birds, of some fish and 
insects, are considerably more numerous than the females. 

The proportion between the sexes fluctuates slightly during 
successive years : thus with race-horses, for every 100 mares born 
the stallions varied from 107'1 in one year to 92-6 in another year, 
and with greyhounds from 116"3 to 95*3. But had larger num- 
bers been tabulated throughout an area more extensive than 
England, these fluctuations would probably have disappeared ; 
and such as they are, would hardly suffice to lead to efi'ective 
sexual selection in a state of nature. Nevertheless, in the cases 
of some few wild animals, as shewn in the supi3lement, the 
proportions seem to fluctuate either during different seasons 
or in different localities in a sufficient degree to lead to such 
selection. For it should be observed that any advantage, 
gained during certain years or in certain localities by those males 
which were able to conquer their rivals, or were the most 
attractive to the females, would probably be transmitted to the 
offspring, and would not subsequently be eliminated. During 
the succeeding seasons, when, from the equality of the sexes, 
every male was able to procure a female, the stronger or more at- 
tractive males previously produced would si ill 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 

Chap. VI II. Sexual Selection. 217 

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 sufificicnt to lead them to 
collect and guard a harem "of females. That some relation exists 
between polygamy and the development of secondary sexual 
characters, appears nearly certain ; and this supports the view 
that a numerical preponderance of males would be eminently 
favourable to the action of sexual selection. Nevertheless many 
animals, which are strictly monogamous, especially birds, display 
strongly-marked secondary sexual characters ; whilst some few 
animals, which are polygamous, do not have such characters. 

\Ye will jfirst briefly run through the mammals, and then turn 
to birds. The gorilla seems to be polygamous, and the 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 Mycetts caraya presents well- 
marked sexual differences, in colour, beard, and vocal organs ; 
and the male generally lives with two or three wives : the male 
of the Cehus 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 sexual differences more frequently than almost any 
other group of mammals; this holds good, especially in their 
weapons, but also in other characters. Most deer, cattle, and 
sheep are polygamous ; as are most antelopes, though some are 
monogamous. Sir Andrew Smith, in speaking of the antelopes 
of South Africa, says that in herds of about a dozen there was 
rarely more than one mature male. The Asiatic Amilope saiga 
appears to be the most inordinate polygamist in the world ; for 
Pallas ^^ states that the male drives away all rivals, and collects a 
herd of about a hundred females and kids together ; the female 
is hornless and has softer hair, but does not otherwise differ 
much from the male. The wild horse of the Falkland Islands and 
of the Western States of N. America is polygamous, but, except 
in his greater size and in the proportions of his body, differs but 
little from the mare. The wild boar presents well-marked sexual 

" On the Gorilla, Savage and Fasc. xii. 1777, p. 29, Sir Andrew 

Wyman. ' Boston Journal of Nat. Smith, ' Illustrations of the Zoology 

Hist.* vol. V. 1845-47, p. 423. On of S. Africa,' 1849, pi. 29, on the 

Cynocephalus, Brehm, 'lUust.Thier- Kobus. Owen, in his ' Anatomy of 

leben,' B. i. 1864, s. 77. On My- Vertebrates' (vol. iii. 1868, p. 6":33) 

cetes, Rengger, 'Xaturgesch.: Siiuge- gives a table shewing incidentally 

thiere von Paraguay,' 1830, s. 14, which species of antelopes are gre- 

20. Cebus, Brehm, 'ibid. s. 108, garious. 

" Pallas, 'S])icilegia Zoolog.,' 

2 1 8 The Descent of Man. Pakt II. 

characters, in his gi'eat tusks and some other points. In Europe 
and in India he leads a solitary hfe, except during the breeding- 
season ; but as is beUeved by Sir W. Elliot, who has had many 
opportunities in India of observing this animal, he consorts at 
this season "with several females. "Whether this holds good 
in Europe is doubtful, but it is supported by some evidence. 
The adult male Indian elephant, like the boar, passes much of 
Ms 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 
Piodents being polygamous, excepting that amongst the Eodents, 
the common rat, according to some rat-catchers, lives with several 
females. Nevertheless the two sexes of some sloths (Edentata) 
differ in the character and colour of certain patches of hair on 
their shoulders.^^ And many kinds of bats (Chehoptera) present 
well-marked sexual differences, chiefly in the males possessing 
odoriferous glands and pouches, and by their being of a lighter 
colour.^^ In the great order of Eodents, as far as I can learn, 
the sexes rarely differ, and when they do so, it is but shghtly in 
the tint of the fur. 

As I hear from Sir Andrew Smith, the lion in South Africa 
sometimes lives with a single female, but generally with more, 
and, in one case, was found with as many as five females ; so 
that he is polygamous. As far as I can discover, he is the only 
polygamist amongst all the terrestrial Carnivora, and he alone 
presents well-marked sexual characters. If, however, we turn 
to the marine Carnivora, as we shall hereafter see, the case is 
widely different ; for many species of seals offer extraordinary 
sexual differences, and they are eminently polygamous. Thus, 
according to Peron, the male sea-elephant of the Southern Ocean 
always possesses sever-ai 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 

^2 Dr. Campbell, in ' Proc. Zoo- ' '^ Dr. Gray, in * Annals and 

log. Soc' 1869, p. 138. See also an Mag. of Nat. Hist.' 1871, p. 302. 

interesting paper, by Lieut. John- ^'^ See Dr. Dobson's excellent 

stone, in ' Proc. Asiatic Soc. of paper, in ' Proc. Zoolog. Soc' 1873, 

Bengal,' May, 1868. p. ii41. 

CiiAP. VIII. Sexual Selection. 219 

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 tlie social species, or rather 
" those of which the males have harems, the males are vastly 
" larger than the females." 

Amongst birds, many species, the sexes of which differ greatly 
from each other, are certainly monogamous. In Great Britain 
we see well-marked sexual differences, for instance, in the wild- 
duck which pairs with a single female, the common blackbird, 
and the bullfinch which is said to pair for life. I am informed 
by Mr. Wallace that the like is true of the Chatterers or 
Cotingidcie of South America, and of many other birds. In several 
groups I have not been able to discover whether the species are 
polygamous or monogamous. Lesson says that birds of paradise, 
so remarkable for their sexual differences, are polygamous, but Mr. 
Wallace doubts wdiether he had sufficient evidence. IMr. Salviu 
tells me he has been led to believe that humming-bii'ds 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 

The Gaihnacese exhibit almost as strongly marked sexual 
differences as birds of paradise or humming-birds, and many of 
the species are, as is well known, polygamous ; others being 
strictly monogamous. What a contrast is presented between the 
sexes of the polygamous peacock or pheasant, and the mono- 
gamous guinea-fowl or partridge ! Many similar cases could be 
given, as in the grouse tribe, in which the males of the poly- 
gamous capercailzie and black-cock differ greatly from the 
females; whilst the sexes of the monogamous red grouse and 
ptarmigan differ very little. In the Cursores, except amongst 
the bustards, few species offer strongly-marked sexual dif- 
ferences, and the great bustard {0th tarda) is said to be poly- 
gamous. With the Grallatores, extrem.ely few species differ 
sexually, but the ruff {Machetes jniunax) affords a marked 

" The Eared Seals, ' American Great Bustard, see L. Lloyd, ' Game 

Naturalist,' vol. iv., Jan. 1871. Birds of Sweden,' 18G7, p. 19, and 

'^ 'The Ibis,' vol. iii. 1861, p. 182. Montagu and Selby speak of 

133, on the Progne Widow-bird. the Black Grouse as polygamous 

See also on the Vidua axillaris^ and of the Red Grouse as mono- 

ibid. vol. ii. 1860, p. 211. On the gamous. 
polygamy of the Capercailzie and 

220 The Descejit of Man. Part II. 

exception, and this species is belieyed by Montagu to be a 
polygamist. Hence it appears that amongst bii'ds there often 
exists a close relation between polygamy and the development of 
strongly-marked sexual differences. I asked Mr. Bartlett, of the 
Zoological Gardens, who has had yery large experience with 
birds, whether the male tragopan (one of the Gallinacese) was 
polygamous, and I was struck by his answering, " I do not 
" know, but should think so from his splendid colours." 

It deserves notice that the instinct of pairing with a single 
female is easily lost under domestication. The wild-duck is 
strictly monogamous, the domestic-duck highly polygamous. 
The Eev. W. D. Fox informs me that out of some half-tamed 
wild-ducks, on a large pond in his neighbourhood, so many 
mallards were shot by the gamekeeper that only one was left for 
every seven or eight females ; yet unusually large broods were 
reared. The guinea-fowl is strictly monogamous ; but Mr. Fox 
finds that his birds succeed best when he keeps one cock to two 
or three hens. Canary-birds pair in a state of nature, but the 
breeders in England successfully put one male to four or five 
females. I have noticed these cases, as rendering it probable 
that wild monogamous species might readily become either 
temporarily or permanently polygamous. 

Too little is known of the habits of reptiles and fishes to enable 
us to speak of their marriage arrangements. The stickle -back 
(Gasterosteus), however, is said to be a polygamist ;" and the 
male during the breeding season differs conspicuously from the 

To sum up on the means through which, as far as we can 
judge, sexual selection has led to the development of secondary 
sexual characters. It has been shewn that the largest number 
of vigorous offspring will be reared from the pairing of the 
strongest and best-armed males, victorious in contests over 
other males, with the most vigorous and best-nourished females, 
which are the first to breed in the spring. If such females select 
the more attractive, and at the same time vigorous males, they 
will roar a larger number of offspring than the retarded females, 
which must pair with the less vigorous and less attractive 
males. So it will be if the more vigorous males select the more 
attractive and at the same time healthy and vigorous females ; 
and this will especially hold good if the male defends the 
female, and aids in providing food for the young. The ad- 
vantage thus gained by the more vigorous pairs in rearing a 
larger number of offspring has apparently sufficed to render 
sexual selection efficient. But a large numerical preponderance 

1^ Noel Humphreys, ' River Gardens/ 1857. 

Chap. VIII. Sexual Selection. 221 

of males over females will bo still more efiBcient; whether the 
preponderance is only occasional and local, or permanent; 
whether it occurs at birth, or afterwards from the greater de- 
struction of the females ; or whether it indirectly follows from 
the practice of polygamy. 

The Male generally more raodified 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 
moditied ; for, generally, the female 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 animals having stronger passions than the females. 
Hence it is the males that tight together and sedulously display 
their charms before the females ; and the victors transmit their 
superiority to their male offspring. Why both sexes do not thus 
acquire the characters of their fathers, will be considered here- 
after. That the males of all mammals eagerly pursue the 
females is notorious to every one. So it is with birds ; but many 
cock birds do not so much pursue the hen, as display their 
plumage, perform strange antics, and pour forth their song in 
her presence. The male in the few fish observed seems much 
more eager than the female; and the same is true of aUigators, 
and apparently of Batrachians. Throughout the enormous class of 
insects, as Kirby remarks, ^^ " the law is, that the male shall seek 
" the female." Two good authorities, Mr. Blackwall and Mr. C. 
Spence Bate, tell me that the males of spiders and crustaceans 
are more active and more erratic in their habits than the females. 
When the organs of sense or locomotion are present in the one 
sex of insects and crustaceans and absent in the other, or when, 
as is frequently the case, they are more highly developed in the 
one than in the other, it is, as far as I can discover, almost 
invariably the male which retains such organs, or has them most 
developed; and this shews that the male is the more active 
member in the courtship of the sexes.^^ 

'^ Kirby and Spence, * Introduc- females of this species are impreg- 

tion to Entomology,' vol. iii. 1826, nated by the males which are born 

p. 342. in the same cells with them ; but 

^^ One parasitic Hymenopterous it is much more probable that the 

insect (Westwood, ' Modern Class, of females visit other cells, so that 

Insects,' vol. ii. p. 160) forms an close interbreeding is thus avoided, 

exception to the rule, as the male We shall hereafter meet in various 

has rudimentary wings, and never classes, with a few exceptional cases, 

quits the cell in which it is born, in which the female, instead of the 

whilst the female has well-develcped male, is the seeker and wooer, 
wings. Audouin believes that the 

222 The Descent of Man. Part XL 

The female, on the other hand, with the rarest exceptions, 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 endeavouring for a long time to escape from 
the male. Every observer of the habits of animals will be able 
to call to mind instances of this kind. It is shown by various 
facts, given hereafter, and by the results fairly attributable to 
sexual selection, that the female, though comparatively passive, 
generally exerts some choice and accepts one male in preference 
to others. Or she may accept, as appearances would sometimes 
lead us to beheve, not the male which is the most attractive to 
her, but the one which is the least distasteful. The exertion of 
some choice on the part of the female seems a law almost as 
general as the eagerness of the male. 

We are naturally led to enquire why the male, in so many and 
such distinct classes, has become more eager than the female, so 
that he searches for her, and plays the more active part in court- 
ship. It would be no advantage and some loss of power if each 
sex searched for the other; but why should the male almost 
always be the seeker? The ovules of plants after fertili- 
sation have to be noiuished for a time; hence the pollen is 
necessarily brought to the female organs — being placed on the 
stigma, by means of insects or the wind, or by the spontaneous 
movements of the stamens ; and in the Algas, &c., by the loco- 
motive power of the antherozooids. With lowly-organised 
aquatic animals, permanently affixed to the same spot and having 
their sexes separate, the male element is invariably brought to 
the female ; and of this we can see the reason, for even if the 
ova were detached before fertilisation, and did not require 
subsequent nourishment or protection, there would yet be greater 
difficulty in transporting them than the male element, because, 
being larger than the latter, they are produced in far smaller 
numbers. So that many of the lower animals are, in this re- 
spect, analogous with plants.^^ The males of affixed and aquatic 
animals having been led to emit their fertilising element in 
this way, it is natui'al that any of their descendants, which 
rose in the scale and became locomotive, should retain the same 
habit ; and they would approach the female as closely as jdos- 
sible, in order not to risk the loss of the fertilising element in a 
long passage of it thi'ough the water. With some few of the lower 

'" 'Essays and Observations.' of the male and female reproductive 

edited .by Owen, vol. i. 1861, p. cells, remarks, " verhalt sich die 

194. " eine bei der Vereinigung activ, 

2^ Prof. Sachs (' Lehrbuch der "... die andere erscheint bei der 

Botanik,' 1870, s. 633) in speaking " Vereinigung passiv." 

Chap. VIII. Seximl Selection. 223 

animals, the females alone are fixed, and the males of these must 
be the seekers. But it is difficult to understand why the males of 
species, of which the progenitors wxre 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 efiSciently, it would be necessary that 
they should be endowed with strong passions ; and the acquire- 
ment of such passions would naturally follow from the more 
eager leaving a larger number of offspring than the less eager. 
' The great eagerness of the males has thus indirectly led to their 
much more frequently developing secondary sexual characters 
than the females. But the development of such characters 
would be much aided, if the males were more liable to vary than 
the females — as I concluded they were — after a long study of 
domesticated animals. Yon Nathusius, who has had very wide 
experience, is strongly of the same opinion.^^ Good evidence also 
in favour of this conclusion can be produced by a comparison 
of the two sexes in mankind. 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 " the greatest number of 
'' abnormalities in each subject is found in the males," He had 
previously remarked that "altogether in 102 subjects, the varieties 
" of redundancy were found to be half as many again as in 
" females, contrasting widely with the greater frequency of 
" deficiency in females before described." Professor Macalister 
likewise remarks ^^ that variations in the m.uscles " are probably 
" more common in males than females." Certain muscles which 
are not normally present in mankind are also more frequently 
developed in the male than in the female sex, although excei^tions 
to this rule are said to occur. Dr. Burt Wilder ^"^ has tabulated 
the cases of 152 individuals with supernumerary digits, of which 
86 were males, and 39, or less than half, females, the remaining 
27 being of unknown sex. It should not, however, be overlooked 

22 * Vortrage liber Viehzucht,' my ' Variation of Animals and 

1872, p. 63. Plants under Domestication,' vol, ii. 

-^ ' Reise der Kovara : Anthro- 1868, p. 75. 

polog. Theil,' 1867, s. 216-269. ^4 'Proceedings Royal Soc' vol. 

The results were calculated by Dr. xvi. July 1868, pp. 519 and 524. 

Weisbach from measurements made -^ ' Troc. Royal h-ish Academy,' 

by Drs. K. Scherzer and Schwarz. vol. x. 1868, p. 123. 

On the greater variability of the 2" 'Massachusetts Me<lical Soc' 

males of domesticated animals, see vol. ii. No. 3, 1868, p. 9. 

224 The Descent of Man. Part 1 J. 

that women would more freqnently endeaTour 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 temperature 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 in- 
dependently of selection the two sexes, from differing constitu- 
tionally, tend to vary in a somewhat different manner. The 
female has to expend much organic matter in the formation of 
her ova, whereas the male expends much force in fierce contests 
with his rivals, in wandering about in search of the female, in 
exerting his voice, pouring out odoriferous secretions, &c, : and 
this expenditure is generally concentrated within a short period. 
The great vigour of the male during the season of love seems 
often to intensify his colours, independently of any marked dif- 
ference /rom 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 in very different ways and at different rates. 

From the causes just specified the two sexes can hardly fail to 
differ somewhat in constitution, at least during the breeding 
season; and, although they may be subjected to exactly the 
same conditions, they will tend to vary in a different manner. 
If such variations are of no service to either sex, they will not be 
accumulated and increased by sexual or natural selection. Never- 
theless, they may become ^Dermanent if the exciting cause acts 

^'^ 'Archiv fiir Path. Anat. und and retention by them of the sperm- 

Phys.' 1871, p. 488. atic fluid; but this can hardly be 

^'^ The conclusions recently ar- the case; for many male birds, for 

rived at by Dr. J. Stockton Hough, instance young pheasants, become 

on the temperature of man, are brightly coloured in the autumn of 

given in the ' Pop. Science Review,' their first year. 
Jan. 1st, 1874, p. 97. ^** For mankind, see Dr. J. Stock- 

-^ Prof. Mantegazza is inclined ton Hough, whose conclusions are 

to believe (' Lettei-a a Carlo Darwin,' given in the 'Pop. Science Review,' 

•Archivio per 1' Anthr opologia,' 1874, p. 97. See Girard's observa- 

1871, p. 306) that the bright tions on the Lepidoptera, as given 

colours, common in so many male in the ' Zoological Record,' 1869, p. 

animals, are due to the presence 347. 

Chap. VIll. Sexual Selection. 225 

permanently ; and in accordance witli a frequent form of inheri- 
tance they may be transmitted to that sex alone in which they 
first appeared. In this case the two sexes will come to present 
permanent, yet unimportant, differences of character. For 
instance, Mr, Allen shews that with a large number of birds 
inhabiting the northern and southern United States, the s])cci- 
mens from the south are darker-coloured than those from the 
north ; and this seems to be the direct result of the difference in 
temperature, light, &c., between the two regions. Now, in some 
few cases, the two sexes of the same species appear to have been 
differently affected ; in the Agdcms 2'>hoeniceus the males have had 
their colours gi-eatly intensified in the south; w^hereas with Cur- 
diualis Virginia nus it is the females which have been thus affected ; 
with Quiscahis major the females have been rendered extremely 
variable in tint, whilst the reales 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 colours, 
greater size, strength, or pugnacity. With birds there has some- 
times been a complete transposition of the ordinary characters 
proper to each sex ; the females having become the more eager 
in courtship, the males remaining comparatively passive, but 
apparently selecting the more attractive females, as we may infer 
from the results. Certain hen birds have thus been rendered 
more highly coloured or otherwise ornamented, as well as more 
powerful and jDugnacious than the cocks ; these characters being 
transmitted to the female offspring alone. 

It may be suggested that in some cases a double process of 
selection has been carried on; that the males have selected 
the more attractive females, and the latter the more attractive 
males. This process, however, though it might lead to the 
modification of both sexes, would not make the one sex 
different from the other, unless indeed their tastes for the beauti- 
ful differed ; but this is a supposition too improbable to be worth 
considering in the case of any animal, excepting man. There 
are, however, many animals in which the sexQs resemble each 
other, both being furnished with the same ornaments, which 
analogy would lead us to attribute to the agency of sexual 
selection. In such cases it may be suggested with more plausi- 
bility, that there has teen a double or mutual process of sexual 
solection ; the more vigorous and precocious females selecting 
the more attractive and vigorous males, the latter rejecting all 
except tho more attractive females. But from what we know 

*' ' Mamtuals and Birds of E. Florida,' pp. 234, 280, 295. 

226 The Descent of Man. Paet II. 

of the habits of animals, this view is hardly probable, for the 
male is generally eager to pair Tvith any female. It is more 
probable that the ornaments common to both sexes were acquired 
by one sex, generally the male, and then transmitted to the off- 
spring of both sexes. If, indeed, during a lengthened period the 
males of any species were gi'eatly 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 

We shall hereafter see that many animals exist, of which 
neither sex is brilliantly coloured or provided with special orna- 
ments, and yet the members of both sexes or of one alone have 
probably acquired simple colour's, such as white or black, through 
sexual selection. The absence of bright tints or other ornaments 
may be the result of yariations of the right kind never having 
occurred, or of the animals themselves having preferred iDlain 
black or white. Obscure tints have often been developed 
through natural selection for the sake of protection, and the 
acquii-ement through sexual selection of conspicuous colours, 
appears to have been sometimes checked from the danger thus 
incurred. But in other cases the males during long ages may 
have struggled together for the possession of the females, and 
yet no effect will have been produced, unless a larger number of 
offspring were left by the more successful males to inherit their 
superiority, than by the less successful : and this, as previously 
shewn, depends on many complex contingencies. 

Sexual selection acts in a less rigorous manner than natural 
selection. The latter produces its effects by the life or death at 
all ages of the more or less successful individuals. Death, indeed, 
not rarely ensues from the conflicts of rival males. But generally 
the less successful male merely fails to obtain a female, or obtains a 
retarded and less vigorous female later in the season, or, if poly- 
gamous, obtains fewer females ; so that they leave fewer, less vigor- 
ous, or no offspring. In regard to structures acquired through 
ordinary or natural selection, there is in most cases, as long as the 
conditions of hfe remain the same, a limit to the amount of 
advantageous modification in relation to certain special purposes ; 
but in regai'd to structures adapted to make one male victorious 
over another, either in fighting or in charming the female, there 
is no definite limit to the amount of advantageous modification ; 
so that as long as the proper variations arise the work of sexual 
selection will go on. This circumstance may partly account for 
tlie frequent and extraordinary amount of variability presented 

CfiAP. VIII. Sexual Selection. 227 

by secondary sexual characters. Nevertheless, natural selection 
-will determine that such characters shall not be acquired by the 
Tictorious males, if they would be highly injurious, either by 
expending too much of their vital powers, or by exposing them 
to any great danger. The development, however, of certain 
structures— of the horns, for instance, in certain stags — has been 
carried to a wonderful extreme ; and in some cases to an extreme 
which, as far as the general conditions of life are concerned, 
must be slightly injurious to the male. From this fact we learn 
that the advantages which favoured males derive from conquer- 
ing other males in battle or courtship, and thus leaving a 
numerous progeny, are in the long run greater than those derived 
from rather more perfect adaptation to their conditions of life. 
We shall further see, and it could never have been anticipated, 
that the power to charm the female has sometimes been more 
important than the power to conquer other males in battle. 


In order to understand how sexual selection has acted on many 
animals of many classes, and in the course of ages has produced 
a conspicuous result, it is necessary to bear in mind the laws of 
inheritance, as far as they are known. Two distinct elements 
are included under the term " inheritance " — the transmission, 
and the development of characters ; but as these generally go 
together, the distinction is often overlooked. We see this dis- 
tinction in those characters which are transmitted through 
the early years of life, but are developed only at maturity 
or during old age. We see the same distinction more clearly 
with secondary sexual characters, for these are transmitted 
through both sexes, though developed in one alone. That they 
are present in both sexes, is manifest when two species, having 
strongly-marked sexual characters, are crossed, for each trans- 
mits the characters proper to its own male and female sex to the 
liybrid offspring of either sex. The same fact is likewise mani- 
fest, when characters proper to the male are occasionally deve- 
loped in the female when she grows old or becomes diseased, 
as, for instance, when the common hen assumes the flowing tail- 
feathers, hackles, comb, spurs, voice, and even i^ugnacity of the 
cock. Conversely, the same thing is evident, more or less plainly, 
with castrated mal es. Again, independently of old age or disease, 
characters are occasionally transferred from the male to the 
female, as when, in certain breeds of the fowl, spurs regularly 
appear in the young and healthy females. But in truth they are 
simply developed in the female ; for in every breed each detail 

228 The Descent of Man. Part II. 

in the structure of tlie spur is transmitted through the female 
to her male offspring. Many cases will hereafter be given, where 
the female exhibits, more or less perfectly, characters proper to 
the male, in whom they must have been first developed, and then 
transferred to the female. The converse case of the first de- 
velopment of characters in the female and of transference to the 
male, is less frequent ; it will therefore be well to give one strik- 
ing instance. With bees the pollen-collecting apparatus is used 
by the female alone for gathering pollen for the larvae, yet in 
most of the species it is partially developed -in the males 
to whom it is quite useless, and it is perfectly developed 
in the males of Bombus or the humble-bee.^^ As not a 
single other Hymenopterous insect, not even the wasp, which is 
closely allied to the bee, is provided with a pollen-collecting 
apparatus, we have no grounds for supposing that male bees 
primordially collected pollen as .well as the females ; although 
we have some reason to suspect that male mammals primordially 
suckled their young as well as the females. Lastly, in all cases of 
reversion, characters are transmitted through two, three, or many 
more generations, and are then developed under certain unknown 
favourable conditions. This important distinction between 
transmission and development will be best kept in mind by the 
aid of the hypothesis of pangenesis. According to this hypothesis, 
every unit or cell of the body throws off gemmules or undeveloped 
atoms, which are transmitted to the offspring of both sexes, and 
are multiphed by self-division. They may remain undeveloped 
during the early years of life or during successive generations; 
and their development into units or cells, like those from which 
they were derived, depends on their affinity for, and union 
with other units or cells previously developed in the due order 
of growth. 

Inheritance at corresponding Periods of Life. — This tendency 
is well established. A new character, appearing in a young 
animal, whether it lasts throughout life or is only transient, will,' 
in general, reappear in the offspring at the same age and last 
for the same time. If, on the other hand, a new character 
appears at maturity, or even during old age, it tends to re- 
appear in the offspring at the same advanced age. When devia- 
tions from this rule occur, the transmitted characters much 
oftenor appear before, than after the corj-esponding age. As I 
have dwelt on this subject sufficiently in another work,^^ I will 

^- H. Miiller, ' Anweudung der ^^ 'The Variation of Animals 

Darwin'schen Lehre,' &c. Verb. and Plants under Domestication,' 
d. n. V. Jahrg. xxix. p. 42. vol. ii. 1868, p. 75. In the last 

Chap. Vlll. Sexual Selection. 229 

here merely give two or three instances, for the sake of recalling 
the subject to the reader's mind. In several breeds of the Fowl, 
the down-covered chickens, the young birds in their first true 
X)limiage, and the adults differ greatly from one another, as well 
as from their common parent-form, the Gallus hankiva ; and 
these characters are faithfully transmitted by each breed to their 
offspring at the corresponding periods of life. For instance, the 
chickens of spangled Hamburg's, whilst covered with down, have 
a few dark spots on the head and rump, but are not striped 
longitudinally, as in many other breeds ; in their first true plu- 
mage, " they are beautifully pencilled," that is each feather is 
transversely marked by numerous dark bars ; but in their second 
plumage the feathers all become spangled or tipped with a dark 
round spot.^^ Hence in this breed variations have occurred at, 
and been transmitted to, three distinct periods of life. The 
Pigeon offers a more remarkable case, because the aboriginal 
parent species does not undergo any change of plumage with 
advancing age, excepting that at maturity the breast becomes 
more iridescent ; yet there are breeds which do not acquire their 
characteristic colours until they have moulted two, three, or 
four times ; and these modifications of plumage are regularly 

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 
colours and other decorations during the breeding-season alone. 
Pallas states,^^ that in Siberia domestic cattle and horses become 
lighter-coloured during the winter ; and I have myself observed, 
and heard of similar strongly marked changes of colour, that is, 
from brownish cream-colour or reddish-brown to a perfect white, 
in several ponies in England. Although I do not know that this 
tendency to change the colour of the coat during different seasons 

chapter but one, the provisional mals,' &c., vol. i. pp. 160, 249 ; 

hypothesis of pangenesis, above vol. ii. p. 77. 

alluded to, is fully explained. " ' Novte species Quadrupeduui e 
^* These Aicts are given on the Glirium ordine,' 177<S, p. 7. On 
high authority of a great breeder, the transmission of colour by the 
Mr. Teebay ; see Tegetmeier's ' Poul- horse, see ' Variation of Animals, 
try Book,' 1868, p. 158. On the &c., under Domestication,' vol. i. p. 
characters of chickens of different 51. Also vol. ii. p. 71, for a gene- 
breeds, and on the bi-eeds of the ral discussion on ' Inheritance as 
pigeon, alluded to in the following limited by Sex.' 
paragraph, see ' Variation of Ani- 

230 The Descent of Man. Part II. 

is transmitted, yet it probably is so, as all shades of colour 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 :ly Sex. — The equal transmission of 
characters to both sexes is the commonest form of inheritance, 
at least with those animals which do not present strongly-marked 
sexual differences, and indeed with many of these. But characters 
are somewhat commonly transferred exclusively to that sex, in 
which they first appear. Ample evidence on tMs head has been 
advanced in my work on * Variation under Domestication/ but a 
few instances may here be given. There are breeds of the sheep 
and goat, in which the horns of the male differ greatly in shape 
from those of the female ; and these differences, acquired under 
domestication, are regularly transmitted to the same sex. As a 
rule, it is the females alone in cats which are tortoise-shell, 
the corresponding colour in the males being rusty-red. With 
most breeds of the fowl, the characters proper to each sex 
are transmitted to the same sex alone. So general is this form 
of transmission that it is an anomaly when variations in certain 
breeds are transmitted equally to both sexes. There are also 
certain sub-breeds of the fowl in which the males can hardly be 
distinguished from one another, whilst the females differ con- 
siderably in colour. The sexes of the pigeon in the parent-species 
do not differ in any external character; nevertheless, in certain 
domesticated breeds the male is coloured differently from the 
female.^^ The wattle in the English Carrier pigeon, and the crop 
in the Pouter, are more highly developed in the male than in the 
female ; and although these characters have been gained through 
long-continued selection by man, the slight differences between 
the sexes are wholly due to the form of inheritance which has 
prevailed ; for they have arisen, not from, but rather in opposi- 
tion to, the wish of the breeder. 

Most of our domestic races have been formed by the accumula- 
tion of many slight variations; and as some of the successive 
steps have been transmitted to one sex alone, and some to both 
sexes, we find in the different breeds of the same species all 
gradations between great sexual dissimilarity and complete 
similarity. Instances have already been given with the breeds 
of the fowl and pigeon, and under nature analogous cases are 

^^ Dr. Chapnis, ' Le Pigeon Voya- similar differences in certain breeds 

geur Beige,' 1865, p. 87. Boitard at Modena, ' Le variazioni dei 

et Corbie, ' Les Pigeons de Voliere,' Colombi domestici,' del Paolo Bo- 

&c., 1824, p. 173. See, also, on. nizzi, 1873. 

Chap, y HI. Sexual Selection 231 

comraon. With auimals under domestication, but whether in 
nature I will not venture to say, one sex may lose characters 
jjropcr 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 
e^^•es have lost their horns. Again, characters proper to one 
sex may suddenly aj^pear in the other sex; as in those sub- 
breeds of the fowl in which the hens acquire spurs whilst young ; 
or, as in certain Polish sub-breeds, in which the females, as 
there is reason to believe, originally acquired a crest, and sub- 
sequently transferred it to the males. All these cases are in- 
telligible on the hypothesis of pangenesis ; for they depend on 
the gemmules of certain parts, although present in both sexes, 
becoming, through the influence of domestication, either dormant 
or developed in either sex. 

There is one difficult question which it will be convenient to 
defer to a future chapter ; namely, whether a character at first 
developed in both sexes, could through selection be limited in 
its development to one sex alone. If, for instance, a breeder 
observed that some of his pigeons (of which the characters are 
usually transferred in an equal degree to both sexes) varied into 
pale blue, could he by long-continued selection make a breed, 
in which the males alone should be of this tint, whilst the females 
remained unchanged ? I will here oftly say, that this, though 
jDcrhaps 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 fijst limited in their development to the male sex, there would 
not be the least difficulty in making a breed with the two sexes 
of a different colour, as indeed has been effected with a Belgian 
breed, in which the males alone are streaked with black. In a 
similar manner, if any variation appeared in a female pigeon, 
which was from the first sexually limited in its development to 
the females, it would be easy to make a breed with the females 
alone thus characterised ; but if the variation was not thus 
originally limited, the process would be extremely difficult, per- 
haps impossible.^^ 

^' Since the publication of the perieaced a breeder as Mr, Teget- 
first edition of this work, it has meier. After describing some cu- 
been highly satisfactory to me to rious cases in pigeons, of the trans- 
find the following remarks (the mission of colour by one sex alone, 
' Field,' Sept. 1872) from so ex- and the formation of a sub-breed 

232 The Descent of Man. Part II. 

On the Relation between the Period of Development of a Character 
and its Transmission to one Sex or to both Sexes. — "Why certain 
characters should be inherited by both sexes, and other charac- 
ters by one sex alone, namely by that sex in which the character 
first appeared, is in most cases qiiite unknown. We cannot even 
conjectui'e why with certain sub-breeds of the pigeon, black 
striae, though transmitted through the female, should be deve- 
loped in the male alone, whilst every other character is equally 
transferred to both sexes. Why, again, witli cats, the tortoise- 
shell colour should, with rare exceptions, be develoj^ed in the 
female alone. The very same character, such as deficient or su- 
pernumerary digits, colour-blindness, &c., 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 following rules seem often to hold good — 
that variations which first appear in either sex at a late period of 
life, tend to be developed in the same sex alone ; whilst variations 
which first appear early in life in either sex tend to be developed in 
both sexes. I am, however, far from supposing that this is the 
sole determining cause. As I have not elsewhere discussed this 
subject, and as it has an important bearing on sexual selection, 
I must here enter into lengthy and somewhat intricate details. 

It is in itself probable that any character aj^pearing at an 
early age would tend to be inherited equally by both sexes, for 
the sexes do not differ much in constitution before the jDower 
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 ojDposite sex. 

I was first led to infer that a relation of this kind exists, from 
the fact that whenever and in whatever manner the adult male 
differs from the adult female, he differs in the same manner from 
the young of both sexes. The generality of this fact is quite 
remari?:able : it holds good with almost all mammals, birds, 

with this character, he says : " It is *' facts that I have rehited ; but it 

" a singular circumstance that Mr. " is remarkable how very closely 

" Darwin should have suggested the " he suggested the right method of 

" possibility of modifying the sexual " procedure." 

" colours of birds by a course of ^* References are given in my 

" artificial selection. When he did Variation of Animals under Domes- 

'• so, he was in ignorance of these tication,' vol. ii. p. 72. 

Chap. Vlll. Scxnal Selection. 233 

amphibians, and fislies ; also with many crustaceans, spiders, and 
some few insects, such as certain orthoptera and libellul?e. In 
all these cases the variations, through the accumulation of which 
the male acquired his proper masculine characters, must have 
occurred at a somewhat late period of life ; otherwise the young 
males would have been similarly characterised ; and conformably 
with our rule, the variations are transmitted to and developed in 
the adult males alone. When, on the other hand, the adult male 
closely resembles the young of both sexes (these, with rare 
exceptions, being alike), he generally, resembles the adult female; 
and in most of these cases the variations through which the young 
and old acquired their present characters, probably occurred, 
according to our rule, during youth. But there is here room for 
doubt, for characters are sometimes transferred to the offspring 
at an earlier age than that at which they first appeared in the 
parents, so that the parents may have varied when adult, and 
have transferred their characters to their offspring whilst young. 
There are, moreover, many animals, in which the two sexes closely 
resemble each other, and yet both differ from their young ; and 
here the characters of the adults must have been acquired late in 
life ; nevertheless, these characters, in apparent contradiction to 
our rule, are transferred to both sexes. We must not, however, 
overlook the possibility or even probability of successive varia- 
tions of the same nature occurring, under exposure to similar 
conditions, simultaneously in both sexes at a rather late i)eriod 
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 vai'iations 
which occur in either sex early in hfe tend to be transferred to 
both sexes. As it was obviously impossible even to estimate in 
how large a number of cases throughout the animal kingdom 
these two propositions held good, it occurred to me to investigate 
some striking or crucial instances, and to rely on the result. 

An excellent case for investigation is afforded by the Deer 
family. In all the species, but one, the horns are developed 
only in the males, though certainly transmitted through the 
females, and capable of abnormal develoiDment 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 api^ear 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 

234 The Descent of Man. Part II. 

would lead to their development in that sex alone, in which 
they first appeared in the progenitor of the whole Family. Now 
in seven species, belonging to distinct sections of the family and 
inhabiting different regions, in which the stags alone bear horns, 
I find that the horns first appear at periods, varying from nine 
months after birth in the roebnck, 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 
Prof. Nilsson, who kindly made special enquiries for me in 
I^apland, 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 iu one species of the family, and likewise common to 
both sexes in this one species alone. 

In several kinds of antelopes, only the males are provided with 
horns, whilst in the greater number both sexes bear horns. 
With respect to the period of development, Mr. Blyth informs 
me that there was at one time in the Zoological Gardens a young 
koodoo (^4;^^. strepsiceros), of which the males alone are horned, 
and also the young of a closelj^-allied species, the eland (Ant. 
oreas), in which both sexes are horned. Now it is in strict 
conformity with our rule, that in the young male koodoo, 
although ten months old, the horns were remarkably small, con- 
sidering the size ultimately attained by then] ; whilst in the 
young male eland, although only three months old, the horns 
were already very much larger than in the koodoo. It is 
also a noticeable fact that in the prong-horned antelope,'*° 
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 ai^pear 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 

2^ I am much obliged to Mr. tinent, see J. D. Caton, in 'Ottawa 

Cupples for having made enquiries Acad, of Kat. Sc. 1868, p. 13. For 

for me in regard to the Roebuck Cervus EkH of Pegu, see Lieut, 

and Red Deer of Scotland from Mr. Beavan, ' Proc. Zoolog. Soc' 1867, 

Robertson, the experienced head- p. 762. 

forester to the Marquis of Breadal- ^° Antilocapra Americana. I have 

bane. In regard to Fallow-deer, I to thank Dr. Canfield for informa- 

hare to thank Mr. Eyton and tion Avith respect to the horns of the 

others for information. For the female : see also his paper in ' Proc. 

Cervus alces of N. America, see Zoolog. Soc' 1866, p. 109. Also 

•Land and Water,* 1868, pp. 221 Owen, 'Anatomy of Vertebrates,' 

and 254; and for the C. Yirgbuanus vol. iii. p. 627. 
and stronjyLceros of the same con- 

Chap. VJII. Sexual Selection. 235 

ve do know with respect to the horns of deer, cattle, &c., 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, thongh 
not quite equal in size, can be felt, or even seen, at birth or soon 
afterwards.'*^ Our rule, however, seems to fail in some breeds 
of sheep, for instance merinos, in which the rams alone are 
horned; for I cannot find on enquiry,"*^ that the horns are 
developed later in life in this breed than in ordinary sheep in 
■which both sexes are horned. But with domesticated sheep the 
presence or absence of horns is not a firmly fixed character ; for 
a certain proportion of the merino ewes bear small horns, and 
some of the rams are hornless; and in most breeds hornless 
ewes are occasionally produced. 

Dr. W. Marshall has lately made a special study of the pro- 
tuberances so common on the heads of birds,^^ 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 difi'er 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 appear very early in life in accordance 
with rule. The adult male can, however, be distinguished from 
the adult female by the presence of spui's; and conformably 

<i I have been assured that the however, a breed of sheej:) in which, 

horns of the sheep in North Wales as with merinos, the rams alone 

can always be felt, and are some- bear horns ; and Mr. Winwood 

times even an inch in length, at Reade informs me that in one case 

birth. Youatt says ('Cattle,' 1834, observed by him, a young ram. 

p. 277), that the prominence of born on Feb. 10th, iirst shewed 

the frontal bone in cattle penetrates horns on March 6th, so that in this 

the cutis at birth, and that the instance, in conformity with rule, 

horny matter is soon formed over the development of the horns oc- 

it. curred at a later period oi life than 

*2 I am greatly indebted to Prof. in Welsh sheep, in which both sexes 

Victor Carus for having made en- are horned. 

quiries for me, from the highest *^ * Ueber die knocheruen Schadel- 

authorities, with respect to the hocker der Vogel' in the ' Kieder- 

merino sheep of Saxony. On the landischen Archiv fur Zoologie,' 

Guinea coast of Africa there is, Baud I. Heft 2, 1872. 

236 The Descent of Man. Part II. 

with our rule, tliese 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 diifer conspicuously from each other in almost 
every part of their plumage, except in the elegant head-crest, 
which is common to both sexes ; and this is developed very early 
in life, long before the other ornaments, which are confined to the 
male. The wild-duck offers an analogous case, for the beautiful 
green speculum on the wings is common to both sexes, though 
duller and somewhat smaller in the female, and it is developed 
early in life, whilst the curled tail-feathers and other ornaments- 
of the male are developed later.'*^ Between such extreme cases 
of close sexual resemblance and wide dissimilarity, as those of 
the Crossoptilon and peacock, many intermediate ones could be 
given, in which the characters follow our two rules in their order 
of development. 

As most insects emerge from the pupal state in a mature 
condition, it is doubtful whether the period of development can 
determine the transference of their characters to one or to both 
sexes. But we do not know that the coloured scales, for instance, 
in two species of butterflies, in one of which the sexes differ in 
colour, whilst in the other they are ahke, are developed at the 
same relative age in the cocoon. Nor do we know whether all 
the scales are simultaneously developed on the wings of the same 
species of butterfly, in which certain coloured marks are confined 

•** In the common peacock {Paxio sexes; but I have not been able to 

cristatus) the male alone possesses discover whether its full develop- 

spurs, whilst both sexes of the Java ment occurs later in life in the 

Peacock (P. muticus) offer the un- males of such species, than in the 

usual case of being furnished with male of the common duck, as ought 

spurs. Hence I fully expected that to be the case according to our 

in the latter species they would rule. With the allied Mergus ctt- 

have been developed earlier in life cullatus we have, however, a case of 

than in the common peacock; but this kind: the two sexes differ con- 

M. Hegt of Amsterdam informs me, spicuously in general plumage, and 

that with young birds of the pre- to a considerable degree in the 

vious year, of both species, com- speculum, which is pure white in 

pared on April 23rd, 1869, there the male and greyisli-white in the 

was no difference in the develop- female. Now the young males at 

ment of the spurs. The spurs, first entirely resemble the females, 

however, were as yet represented and have a greyish-white speculum, 

merely by slight knobs or eleva- which becomes pure white at an 

tions. 1 presume that I should earlier age than that at which the 

have been informed if any difference adult male acquires his other and 

in the rate of development had more strongly-marked sexual dif- 

been observed subsequently. ferences : see Audubon, ' Ornitho- 

*^ In some other species of the logical Biography,' vol. iii. 1835, 

Duck family the speculum differs pp. 249-250. 
in a greater degree in the two 

Chap. VIII. Sexual Selection. 


to one sex, whilst others are common to both sexes. A difference 
of this kind in the period of development is not so improbable as 
it may at first appear ; for with the Orthoptera, which assume 
their adult state, not by a single metamorphosis, but by a suc- 
cession of moults, the young males of some species at first 
resemble the females, and acquire their distinctive masculine 
characters only at a later moult. Strictly analogous cases occur 
at the successive moults of certain male crustaceans. 

We have as yet considered the transference of characters, re- 
latively to their period of development, only in species in a 
natural state; we will now turn to domesticated animals, and 
first touch on monstrosities and diseases. The presence of super- 
numerary digits, and the absence of certain phalanges, must be 
determined at an early embryonic period— the tendency to profuse 
bleeding is at least congenital, as is probably colour-blindness — 
yet these peculiarities, and other similar ones, are often limited 
in their transmission to one sex; so that the rule that 
characters, developed at an early period, tend to be trans- 
mitted to both sexes, here wholly fails. But this rule as 
before remarked, does not appear to be nearly so general as the 
converse one, namely, that characters which appear late in life 
in one sex are transmitted exclusively to the same sex. From 
the fact of the above abnormal peculiarities becoming attached 
to one sex, long before the sexual functions are active, we may 
infer that there must be some difference between the sexes at an 
extremely early age. With respect to sexually-limited diseases, 
we know too little of the period at which they originate, to draw 
any safe conclusion. Gout, however, seems to fall under our 
rule, for it is generally caused by intemperance during manhood, 
and is transmitted from the father to his sons in a much inore 
marked manner than to his daughters. 

In the various domestic breeds of sheep, goats, and cattle, the 
males differ from theh respective females in the shape or develop- 
ment of their horns, forehead, mane, dewlap, tail, and humjD on 
the shoulders ; and these peculiarities, in accordance with our 
rule, are not fully developed until a rather late period of life. 
The sexes of dogs do not differ, except that in certain breeds, 
especially in the Scotch deer-hound, the male is much larger 
and heavier than the female ; and, as we shall see in a future 
chapter, the male goes on increasing in size to an unusually late 
period of life, which, according to rule, will account for liis in- 
creased size being transmitted to his male offspring alone. On 
the other hand, the tortoise-shell colour, which is confined to 
female cats, is ({uite distinct at bhth, and this case violates the 
rule. There is a breed of pigeons in which the males alone are 

238 The Descent of Man. Part II. 

streaked with black, and the streaks can be detected even in the 
nestlings ; but they become more conspicuous at each successive 
moult, so that this case partly opposes and partly supports the 
rule. With the English Carrier and Pouter pigeons, the full 
development of the wattle and the croj) occurs rather late in life, 
and conformably with the rule, these characters are transmitted 
in full perfection to the males alone. The following cases perhaps 
come within the class previously alluded to, in which both sexes 
have varied in the same manner at a rather late period of life, 
and have consequently transferred their new characters to both 
sexes at a corresponding late period ; and if so, these cases are 
not opposed to our rule : — there exist sub-breeds of the pigeon, 
described by Neumeister,^'' in which both sexes change their 
colour during two or three moults (as is likewise the case with 
the Almond Tumbler), nevertheless, these changes, though 
occurring rather late in life, are common to both sexes. One 
variety of the Canary-bud, namely the London Prize, offers a 
nearly analogous case. 

With the breeds of the Fowl the inheritance of various charac- 
ters by one or both sexes, seems generally determined by the 
period at which such characters are developed. Thus in all the 
many breeds in which the adult male differs greatly in colour 
from the female, as well as from the wild parent-species, he 
differs also from the young male, so that the newly-acquired 
characters must have appeared at a rather late period of Hfe. 
On the other hand, in most of the breeds in which the two sexes 
resemble each other, the young are coloured in nearly the same 
manner as their parents, and this renders it probable that their 
colours first aj^peared early in life. We have instances of this 
fact in all black and white breeds, in which the young and old 
of both sexes are alike ; nor can it be maintained that there is 
something pecuhar 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 coloured. With the so-called Cuckoo sub-breeds of 
the fowl, in which the feathers are transversely pencilled with 
dark stripes, both sexes and the chickens are coloured in nearly 
the same manner. The laced plumage of the Sebright bantam 
is the same in both sexes, and in the young chickens the wing- 
feathers are distinctly, though imperfectly laced. Spangled 
Hamburgs, however, offer a partial exception ; for the two sexes, 
though not quite alike, resemble each other more closely than 

^^ 'DasGanze der Taubonzucht,' puis, * Le pigeon voyageui' Beige,' 
1837, s. 21, 24. For the case of 1865, p. 87. 
the streaked pigeons, see Dr. Cha- 

Chap. VIII. Sexual Selection. 239 

do the sexes of the aborlgiDal parent-species ; yet they acquu-e 
their characteristic phimage late in life, for the chickens are 
distinctly pencilled. With respect to other characters besides 
colour, in the wild-parent species and in most of the domestic 
breeds, the males alone possess a well-developed comb ; but in 
the young of the Spanish fowl it is largely developed at a very 
early age, and, in accordance with this early development in the 
male, it is of unusual size in the adult female. In the Game 
breeds pugnacity is developed at a wonderfully early age, of 
which curious proofs could be given ; and this character is trans- 
mitted to both sexes, so that the hens, from their extreme 
pugnacity, are now generally exhibited in separate pens. With 
the Polish breeds the bony protuberance of the skull which 
supports the crest is partially developed even before the chickens 
are hatched, and the crest itself soon begins to grow, though at 
iirst feebly ;*'^ and in this breed the adults of both sexes are 
characterised by a great bony protuberance and an immense crest. 

Finally, from what we have now seen of the relation which 
exists in many natural species and domesticated races, between 
the period of the develox)ment of their characters and the 
manner of their transmission — for example, the striking fact of 
the early growth of the horns in the reindeer, in which both 
sexes bear horns, in comparison with their much later growth 
in the other species in which the male alone bears horns — we 
may conclude that one, though not the sole cause of characters 
being exclusively inherited by one sex, is their development at 
a late age. And secondly, that one, though apparently a less 
efficient cause of characters being inherited by both sexes, is 
their development at an early age, whilst the sexes differ 
but little in constitution. It appears, however, that some 
difference must exist between the sexes even during a very 
early embryonic period, for characters developed at this age not 
rarely become attached to one sex. 

Summary and concluding remarls. — From the foregoing dis- 
cussion on the various laws of inheritance, we learn that the 
characters of the parents often, or even generally, tend to become 
developed in the offspring of the same sex, at the same age, aud 
periodically at the same season of the year, in which they Iirst 

*' For full particulars and re- 250, 256. In regard to the higher 

ferences on all these points respect- animals, the sexual differences which 

ing the several breeds of the Fowl, have arisen under domestication are 

see 'Variation of Animals and Plants described in the same work under 

under Domestication,' vol. i. pp. the head of each species. 

240 TJie Descent of Man. Part II. 

appeared in the parents. But these rules, owing to unknown 
causes, are far from being fixed. Hence during the modification 
of a species, the successive changes may readily be transmitted 
in different ways ; some to one sex, and some to both ; some to 
the offspring at one age, and some to the offspring at all ages. 
Not only are the laws of inheritance extremely complex, but so 
are the causes which induce and goyem variability. The 
variations thus induced are preserved and accumulated by 
sexual selection, which is in itself an extremely complex affair, 
depending, as it does, on the ardour in love, the courage, and 
the rivab-y 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 towards 
the general welfare of the species. Hence the manner in which 
the individuals of either or both sexes have been affected 
through sexual selection cannot fail to be complex in the highest 

When variations occur late in life in one sex, and are trans- 
mitted to the same sex at the same age, the other sex and the 
young are left 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 hfe in one sex or in both, and be transmitted to both 
sexes at all ages, and then all the individuals of the species 
are similarly modified. In the following chapters it will be seen 
that all these cases frequently occur in nature. 

Sexual selection can never act on any animal before the age 
for reproduction arrives. From the great eagerness of the male 
it has generally acted on this sex and not on the females. The 
males have thus become provided with weapons for fighting 
with their rivals, with organs for discovering and securely 
holding the female, and for exciting or charming her. When 
the sexes differ in these respects, it is also, as we have seen, an 
extremely general law that the adult male differs more or less 
from the young male ; and we may conclude from this fact that 
the successive variations, by which the adult male became modi- 
fied, did not generally occur much before the age for reproduction. 
Whenever some or many of the variations occurred early in 
life, the young males would partake more or less of the charac- 
ters of the adult males ; and differences of this kind between 
the old and young males may be observed in many species of 

It is probable that young male animals have often tended to 
vary in a manner which would not only have been of no use to 
them at an early age, but would have been actually injui'ious— 

Chap. YIII. ScxicjI Selcct^n. 24 1 

as by acquiring bright colours, which would render them con- 
spicuous to their enemies, or by acquiring structures, such as 
great horns, which would exj^end much vital force in their 
development. Variations of this kind occurring in the young 
males would almost certainly be eliminated through natural 
selection. With the adult and experienced males, on the other 
hand, the advantages derived from the acquisition of such 
characters, would more than counterbalance some exposure to 
danger, and some loss of vital force. 

As ■ variations which give to the male a better chance of 
conquering other males, or of finding, securing, or charming the 
opposite sex, would, if they happened to arise in the female, be 
of no service to her, they would not be preserved in her through 
sexual selection. We have also good evidence with domesticated 
animals, that variations of all kinds are, if not carefully selected, 
soon lost through intercrossing and accidental deaths. Conse- 
quently in a state of nature, if variations of the above kind chanced 
to arise in the female line, and to be transmitted exclusively in 
this line, they would be extremely liable to be lost. If, however, 
the females varied and transmitted their newly acquired 
characters to their offspring of both sexes, the characters which 
were advantageous to the males would be preserved by them 
through sexual selection, and the two sexes would in consequence 
be modified in the same manner, although such characters were of 
no use to the females ; but I shall hereafter have to recur to these 
more intricate contingencies. Lastly, the females may acquire, and 
apparently have often acquired by transference, characters from 
the male sex. 

As variations occurring late in life, and transmitted to one 
sex alone, have incessantly been taken advantage of and accumu- 
lated through sexual selection in relation to the reproduction of 
the species ; therefore it appears, at first sight, an unaccountable 
fact that similar variations have not frequently been accumu- 
lated through natural selection, in relation to the ordinary 
habits of life. If this had occurred, the two sexes would often 
have been differently modified, for the sake, for instance, of 
capturing prey or of escaping from danger. Differences of this 
kind between the two sexes do occasionally occur, especially in 
the lower classes. But this implies that the two sexes follow 
different habits in their struggles for existence, which is a rare 
circumstance with the higher animals. The case, however, is 
widely different with the reproductive functions, in which respect 
the sexes necessarily differ. For variations in structure which 
are related to these functions, have often proved of value to one 
sex, and from having arisen at a late period of hfe, have been 

242 Thi^esccnt of Man. Tart II. 

transmitted to one sex alone ; and such variations, thus preserved 
and transmitted, have given rise to secondary sexual characters. 
In the following chapters, I shall treat of the secondary 
sexual characters in animals of all classes, and shall endeavour in 
each case to apply the principles explained in the present 
chapter. The lowest classes will detain us for a very short time, 
but the higher animals, especially birds, must be treated at 
considerable length. It should be borne in mind that for 
reasons already assigned, I intend to give only a few illustrative 
instances of the innumerable structures by the aid of which the 
male finds the female, or, when found, holds her. On the other 
hand, all structures and instincts by the aid of which the male 
conquers other males, and by w^hich he allures or excites the 
female, will be fully discussed, as these are in many ways the 
most interesting. 

Supplemtnt on the proportional numbers of the two sexes in animals 
belonging to various classes. 

As no one, as far as I can discover, has paid attention to the 
relative numbers of the two sexes throughout the animal 
kingdom, I will here give such materials as I have been able to 
collect, although they are extremely imperfect. They consist in 
only a few instances of actual enumeration, and the numbers are 
not very large. As the proportions are known with certainty only 
in mankind, I will first give them as a standard of comparison. 

Man.— In England during ten years (from 1857 to 1866) the 
average number of children born alive yearly was 707,120, in 
the proportion of 104-5 males to 100 females. But in 1857 the 
male births throughout England were as 105-2, and in 1865 as 
104-0 to 100. Looking to separate districts, in Buckingham- 
shire (where about 5000 children are annually born) the mean 
proportion of male to female births, during the whole period of 
the above ten years, was as 102-8 to 100; w^hilst in N. Wales 
(where the average annual births are 12,873) it w^as as high 
as 106-2 to 100. Taking a still smaller district, viz., Eut- 
landshire (where the annual births average only 739), in 1864 
the male births were as 114*6, and in 1862 as only 97-0^ to 
100 ; but even in this small district the average of the 7385 
births during the whole ten years, was as 104-5 to 100 ; that is in 
the same ratio as throughout England.'*^ The proportions are 
sometimes shghtly disturbed by unlmown causes; thus Prof. 

*^ 'Twenty-ninth Annual Report In this report (p. xii.) a special de- 
of the Ilegistnir-Geueral for 1866.* ceunial table is given. 

Chap. Till. Proportion of the Sexes. 243 

Faye states " that in some districts of Norway there has been 
" during a decennial jDeriod a steady deficiency of boys, whilst 
'* in others the opposite condition has existed." In France 
during forty-four years the male to the female births have been 
as I06'2 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 Kussia the average 
proportion is as high as lOS'U, and in Philadelphia in the United 
States as llO'S to lOO."*^ The average for Europe, deduced by 
Bickes from about seventy million births, is 106 males to 100 
females. On the other hand, with w^hite children born at the 
Cape of Good Hope, the proportion of males is so low as to fluctuate 
during successive years bctw^een 90 and 99 males for every 100 
females. It is a singular fact that with Jews the proportion of 
male births is decidedly larger than with Christians : thus in 
Prussia the proportion is as 113, in Breslau as 114, and in 
Livonia as 120 to 100 ; the Christian births in these countries 
being the same as usual, for instance, in Livonia as 104 to lOO."*' 
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 134-6 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 
" unfavourable."^^ 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 

^^ For Norway and Russia, see 343. Dr. Stark also remarks 

abstract of Prof. Faye's researches, ('Tenth Annual Report of Births, 

in 'British and Foreign Medico- Deaths, &c., in Scotland,' 1867, p. 

Chirurg. Review,' April, 1867, pp. xxviii.) that "These examples may 

343, 345. For France, the ' An- " suffice to shew that, at almost 

nuaire pour I'An 1867,' p. 213. " every stage of life, the males in 

For Phihidelphia, Dr. Stockton- " Scotland have a greater liability 

Hough, 'Social Science Assoc' 1874. " to death and a higher death-rate 

For the Cape of Good Hope, Quetelet " than the females. The foct, how- 

as quoted by Dr. H. H. Zouteveen, " ever, of this peculiarity being 

in the Dutch Translation of this " most strongly developed at that 

work (vol. i. p. 417), where much " infantile period of life when the 

information is given on the propor- " dress, food, and genei-al treatment 

tion of the sexes. " of both sexes are alike, seems to 

^*> In regard to the Jews, see M. " prove that the higher male death- 

Thury, 'La Loi de Production des " rate is an impressed, natural, and 

Sexes,' 1863, p. 25. " constitutional peculiarity due to 

*^ ' British and Foreign Medico- " sex alone." 
Chirurg. Review,' April, 1867, p. 

244 The Descent of Man. Part II. 

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. Consequently the still- 
born males are more numerous ; and, as a higlily 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 at birth and for some time sub- 
sequently, and owing to the exposure of grown men to various 
dangers, and to their tendency to emigrate, the females in all 
old-settled countries, where statistical records have been kept,^^ 
are found to preponderate considerably over the males. 

It seems at first sight a mysterious fact that in different 
nations, under different conditions and cHmates, in Naples, 
Prussia, Westphalia, Holland, France, England and the United 
States, the excess of male over female births is less when they 
are illegitimate than when legitimate.^* This has been explained by 
different writers in many different ways, as from the mothers 
being generally young, from the large proportion of first preg- 
nancies, &c. But we have seen that male infants, from the large 
size of their heads, suffer more than fehiale infants diu'ing 
parturition ; and as the mothers of illegitimate children must be 
more liable than other women to undergo bad labours, from 
various causes, such as attempts at concealment by tight lacing, 
hard work, distress of mind, &c., their male infants would 
proportionably suffer. And this probably is the most eflaeient 
of all the causes of the proportion of males to females born 
alive being less amongst illegitimate children than amongst the 
legitimate. With most animals the greater size of the adult 
male than of the female, is due to the stronger males having 
conquered the weaker in their struggles for the possession of 
the females, and no doubt it is owing to this fact that the two 
sexes of at least some animals differ in size at birth. Thus 

*2 < West Riding Lunatic Asylum Paraguay, according to the accurate 

Reports,' vol. i. 1871, p. 8. Sir J. Azara ('Voyages dans I'Amerique 

Simpson has proved that the head merid.' tom. ii. 1809, p. 60, 179), 

of the male infant exceeds that of the women are to the men in the' 

the female by 3-8ths of an inch in proportion of 14 to 13. 
circumference, and by l-8th in ^^ Babbage, ' Edinburgh Journal 

transverse diameter. Quetelet has of Science,' 1829, vol. i. p. 88; also 

shewn that woman is born smaller p. 90, on still-born children. On 

than man; see Dr. Duncan, ' Fe- illegitimate children in England, 

cundity, Fertility, Sterility,' 1871, see 'Report of Registrar-General 

P- 382. for 1866,' p. xv. 

*^ With the savage Guaranys of 

Chap. VJII. Proportion of the Sexes. 245 

M^e have the ctirions fact that we may attribute the more 
frequent deaths of male than female infants, especially amongst 
the illegitimate, at least in part to sexual selection. 

It has often been supposed that the relative age of the two 
parents determines the sex of the offspring ; and Prof. Leuckart^'^ 
has advanced what he considers sufficient evidence, with respect 
to man and certain domesticated animals, that this is one impor- 
tant though not the sole factor in the result. So again the period 
of impregnation relatively to the state of the female has been 
thought by some to be the efficient cause ; but recent observa- 
tions discountenance this belief. According to Dr. Stockton- 
nough,^6 the season of the year, the poverty or wealth of the 
parents, residence in the country or in cities, the crossing of 
foreign immigrants, &c., all influence the proportion of the 
sexes. With mankind, polygamy has also been supposed to lead 
to the birth of a greater proportion of female infants ; but Dr. J. 
Campbell ^^ 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 ^ny animal 
has been rendered so highly polygamous as the English 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 

Horses. — Mr. Tegetraeier Las been so kind as to tabulate for me from 
the ' Kacing Calendar ' the births of race-horses during a period of 
twenty-one years, viz., from 184G to 1867; 1849 being omitted, as no 
returns were that year published. The total births were 25,560,^* con- 
sisting of 12,763 males aiid 12,797 females, or iti tlie proportion of 997 
males to 100 females. As these numbers are tolerably large, and as 
they are drawn from all parts of England, during several years,'we may 
with much confidence conclude that with the domestic horse, or at 
least with the race-horse, the two sexes are produced in almost equal 
numbers. The fluctuations in the proportions during successive years 

" Leuckart (in Wagner 'Hand- notice, as shewing how infertile 

wortorbuch der Phys.' B. iv. 1853, these highly-nurtured and rather 

s. 774. closely-inteibred animals have be- 

5" Social Science Assoc, of Phila- come, that not far from one-third of 

delphia, 1874. the mares failed to produce living 

" ' Anthropological Review,' foals. Thus during 186G, 809 male 

April, 1870, p. cviii. colts and 816 female colts were born, 

^8 During eleven years a record and 743 mares failed to produce 

was kept of the number of mares offspring. During 1867, 836 males 

which proved barren or prematurely and 902 females were born, and 794 

slipped their foals ; and it deserves mares failed. 

246 The Descent of Man. Part 11. 

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 18o7 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 
accidental ; at least I can detect nothing of the kind with man in the 
decennial table in the Eegistrar's Report for 1866. 

DoQs. — During a period of twelve years, from 1857 to 1868, the births 
of a large number of greyhounds, throughout England, were sent to 
the ' Field' newspaper ; and I am again indebted to Mr. Tegetmeier for 
carefully tabulating the results. The recorded births were 6878, 
consisting of 3605 males and 3273 females, that is, in the proportion of 
llO'l 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 llO'l to 100 ia 
probably nearly correct in the case of the greyhound, but whether it 
would hold with other domesticated breeds is iu some degree doubtful. 
Mr. Cupples has enquired, from several great breeders of dogs, and iinds 
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. 

QUee-p. — The sexes of sheep are not ascertained by agriculturists until 
several months after birth, at the period when the males are castrated ; 
so that the following returns do not give the proportions at birth. 
Moreover, I find that several great breeders in Scotland, who annually 
raise some thousand sheep, are firmly convinced that a larger proportion 
of males than of females die during the first year or two. Therefore the 
proportion of males would be somewhat larger at birth than at the age of 
castration. This is a remarkable coincidence with what, as we ijave 
seen, occurs with mankind, and both cases probably depend on the 
same cause. I have received returns from four gentlemen in England 
who have bred Lowdand sheep, chiefly Leicesters, during the last ten to 
sixteen years; they amount altogether to 8965 births, consisting of 
4407 males and 4558 females; that is in the proportion of 96 7 males to 
100 females. With respect to Cheviot and black-faced sheep bred in 
Scotland, I have received returns from six breeders, two of them on a 
large scale, chiefly for the years 1867-1869, but some of the returns 
extend back to 1862. The total number recorded amounts to 50,685, 
consisting of 25,071 males and 25,614 females, or in the proportion of 
97.9 males to 100 females. If we take the English and Scotch returns 
together, the total number amounts to 59,650, consisting of 29,478 
males and 30,172 females, or as 97*7 to 100. So that with sheep at the 
age of castration the females are certainly in excess of the males, but 
probably this would not hold good at birth.^^ 

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- 

^3 I am much indebted to Mr. tion to the premature deaths of the 

Cupples for having procured for me males, — a statement subsequently 

the above returns from Scotland, as confirmed by Mr. Aitcliison and 

well as some of the following re- others. To this latter gentleman, 

turns on cattle. Mr. R. Elliot, of and to Mr. Payan, I owe my thanks 

Laio-hwood, first called my atten- for large returns as to sheep. 

Chap. VIII. Proportion of the Sexes. l.X'j 

calves ; i.e., in the proportion of 91-4 males to 100 females. The Rev. 
W. D. Fox informs me that in 18G7 out of 84 calves born on a farm in 
Derbyshire only one was a bull. Mr. Harrison Weir has enquired from 
several breeders of P/(/.*, and most of them estimate the male to the 
female births as about 7 to 6. This same gentleman has bred liahhits 
for many years, and has noticed that a far greater number of bucks aie 
produced than does. But estimations are of little value. 

Of mammalia in a state of nature I have been able to learn very 
little. In regard to the common rat, I have received conflicting 
statements. Mr, R. Elliot, of Laighwood, informs me that a rat-catchei 
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 
Jiimself subsequently examined some hundred old ones, and found the 
statement true. Mr. F. Buckland has bred a large number of while 
rats, and he also believes that the males greatly exceed the females. 
Tn 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 
describing an antelope of S. 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 arc expelled 
from the herds, and Sir A. Smith says, that though he has himself 
never seen herds consisting of young males alone, others affirm tiiat 
this does occur. It appears probable that the young when expelled 
from the herd, would often fall a prey to the many beasts of prey of the 


With respect to the Fowl, I have received only one account, namely, 
that out of 1001 chickens of a highly-bred fctock of Cochins, reared 
during eight years by Mr. Stretch, 487 proved males and 514 females; 
i.e., as 94-7 to 100. In regard to domestic pigeons tliere is good 
evidence either that the males are produced in excess, or that they live 
longer ; for these birds invariably pair, and single males, as Mr. Teget- 
raeier informs me, can always be purchased cheaper than females. 
Usually the two birds reared from the two eggs laid in the san\e nest 
are a male and a female ; but Mr. Harrison Weir, who has been so lar-^e 
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." 

so Bell, * History of Quad- iv. s. 990) comes to the same oon- 

rupeds,' p. lUO. clu.sioa. 

61 ' Illustrations of the Zoology e^ Qq j-j^g authority of L. Lloyd, 
of S. Africa,' 1849, pi. 29. 'Game Bird.s of Sweden,' 18G7, pp. 

62 Brehm (' Illust. Thierleben,' B. 12, 133 

248 T]ie Descent of Man. Paet II. 

that in Scandinavia the broods of the capercailzie and black-cock 
contain more males than females ; and that with the Dal-ripa (a kind 
of ptarmigan) more males than females attend the lelis or places of 
courtship ; but this latter circumstance is accounted for by some 
observers by a greater number of hen birds being killed by vermin. 
From various facts given by White of Selborne,"* it seems clear that 
the males of the partridge must be in considerable excess in the south 
of England ; and 1 have been assured that this is the case in Scotland. 
Mr. Weir on enquiring from the dealers, who receive at certain seasons 
large numbers of rufl's {Machetes pugnax), was told that the males are 
much the more numerous. This same naturalist has also enquired for 
me from the birdcatchers, who annually catch an astonishing number 
of various small species alive for the London market, and he was un- 
hesitatingly answered by an old and trustworthy man, that with the 
chaffinch the males are in large excess; he thought as high as 2 males to 
1 female, or at least as high as 5 to 3.^^ The males of the blackbird, 
he likewise maintained, were by far the more numerous, whether • 
caught by traps or by netting at night. These statements may 
apparently be trusted, because this same man said that the sexes are 
about equal with the lark, the twite (^Linaria montana)^ and goldfinch. 
On the other hand, he is certain that with the common linnet, the 
females preponderate greatly, but unequally during different years ; 
during some years he has foimd the females to the males as four to one. 
It should, however, be borne in mind, that the chief season for catching 
birds does net 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 1G6 
males and of only 38 females. With two other species the females were 
in excess : but the proportions apparently vary either during ditferent 
seasons or in difterent 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;" whilst 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," whilst in 
Honduras the proportion was the other way, the species there having 
the character of a poiygamiot. 

" 'Nat. Hist, of Selborne,' letter ever caught by one man in a single 

xxix. edit, of 1825, vol. i. p. 139. day was 70. 

®5 Mr. Jenner Weir received ^^ ' Ibis,' a'oI. ii. p. 260, as quoted 

similar information, on making en- in Gould's ' Trcchilidae,' 1861, p. 

quiries during the following year. 5'2. For the foregoing proportions, 

To shew the number of living chaf- I am indebted to Mr. Salvin for a 

finches caught, I may mention that table of his results. 
in 1869 the^re was a match between "^ 'Ibis,' 1860, p. 137; and 1867, 

two experts, and one man caught p. 369. 
in a day 62, and another 40, male "*' ' Ibis,' 1862, p. 137. 

chaffinches. The greatest number 

Chap. VIII. Proportion of the Sexes, 249 


With Fish the proportional numbers of the sexes can be asfertnined 
only by catching them in the adult or neaily adult state ; and there 
are many difficulties in arriving at any just conclusion.'^^ Infertile 
fojuales might readily be mistaken for males, as Dr. Giinther has 
remarked to me in regard to trout. With some species the males are 
believed to die soon after fertilising the ova. Witli many species the 
mules 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. Carbounier/" who has especially attended to the 
natural history of the pike {E^x^x lucins), states that many males, owing 
to tiieir small size, are devoured by the larger females ; and he believes 
that the males of almost all fish are exposed from ihis same cause to 
greaier danger than the females. Nevertheless, in the few cases in 
which the proportional numbers have been actually observed, the 
males appear tj be largely in excess. Thus Mr. R. Uuist, the sujierin- 
tendent of the Stormontfield experiments, says that in 1865, out of 70 
salmon first landed for the purpose of oblaining the ova, upwards of 60 
were males. In 1867 he again " calls attention to the vast disproportion 
•' of the males to the females. We had at the outset at least ten males 
" to one female." Afterwards females sufficient for obtaining ova were 
procured. He adds, " from the great proportion of the males, they are 
"constantly fighting and tearing each other on the spawning-beds."^' 
This disproportion, 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 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 ei^ht males to one 
"female found captive. I cannot quite account for this; either the 
*' males nre more numerous than the females, or the latter seek safety 
" by concealment rather than flight." He then adds, that by carefully 
searching the banks, sufficient females for obtaining ova can be found.'^ 
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 Cyprinidae likewise seem to be in excess ; but 
several members of this Family, viz., the carp, tench, brtam and 
minnow, appear regularly to follow the practice, rare in the animal 
kingdom, of polyandry ; for the female whilst spawning is always 
attended by two males, one on each side, and in the case of the bream 
by three or four males. This fact is so well known, that it is always 
recommended to stock a pond with two male tenches to one female, or 
at least with three males to two females. With the minnow, an 
excellent observer states, that on the spawning-beds the males are ten 
times as numerous as the females; when a female comes amongst the 

«3 Leuckart quotes Bloch (Wag- 18, 1869, p. 3G9. 

ner, ' Handworterbuch der Phys.' " ' The Stormontfield Piscicul- 

B. iv. 1853, s. 775), that with fish tural Experiments,' 186G, p. 23. 

there are twice as many males as The ' Field ' newspaper, June 29th, 

females. 1867. 

^0 Quoted in the 'Farmer,' March " ' Land and Water,' 1868, p. 41. 

250 The Descent of Man. Part 11. 

males, *' she is imraediatelj' pressed closely by a male oa each side ; 
"and when they have been in that situation for a time, are superseded 
" by other two males." "^ 


In this great Class, the Lepidoptera almost alone afford means for 
judging of the proportional numbers of the sexes ; for they have been 
collected with special care by many good observers,' and have been 
largely bred from the egg or caterpillar state. I had hoped that some 
breeders of silk-moths might have kept an exact record, but after 
writing to France and Italy, and consulting various treatises, I cannot 
hud that this has ever been done. Tiie general opinion appears to be 
that the sexes are nearly equal, but in Italy, as I hear from Professor 
Canestrini, many breeders are convinced that the females are produced 
in excess. This same naturalist, however, informs me, that in the two 
yearly broods of the Ailanthus silk-moth (Bomhijx cynthia), the males 
greatly preponderate in the first, whilst in the second the two sexes are 
nearly equal, or the females rather in excess. 

In regard to Butterflies in a state of nature, several obseivers have 
been much struck by the apparently enormous proponderance of the 
males.'^ Thus Mr. JBates,'^ in speaking of several species, about a 
hundred in number, which inhabit the Upper Amazons, says that the 
males are much more numerous than the females, even in the propor- 
tion of a hundred to one. In North America, Edwards, who had great 
experience, estimates in the genus Papilio the males to the females as 
four to one ; and Mr. Walsh, who informed me of this statement, says 
that with P. turims this is certainly the case. In South Africa, Mr. K. 
Trimen found the males in excess in 19 species ;"" and in one of these, 
which swarms in optn places, he estimated the number of males as 
fifty to one female. With another speoes, in which the males are 
numerous in certain localities, lie collected only five feuiales during 
seven years. In the island of Bourbon, M. IVLdllard states that the 
males of one species of Papilio are twenty times as numerous as the 
females.^^ Mr. Trimen informs me that as far as he has himself seen, 
or heard from others, it is rare for the females of any butterfly to 
exceed the males in number ; but three South African species per- 
haps oifer an exception. Mr. Wallace '* states that the females of 
Orintlwjjtera croesus, in the Malay archipelago, are more common and 
more easily caught than the males ; but this is a rare butterfly. I may 

' " Yarrell, ' Hist. British Fishes,' or four times as numerous as the 

vol. i. 1826, p. 307 ; on the Cyprhvis females. 

ca/'jDiO, p. 331; on the Tmcavu/gram, " 'The Naturalist on the Ama- 

p. 331 ; on the Ahmmis braina, p. zons,' vol. ii. 18B3, p. 228, 347. 
336. See, for the minnow (Leu- "« Four of cases are given 

ciscus phoxin'is), ' Loudon's Mag. of by Mr. Trimen in his ' Rhopalocera 

Nat. Hist.' vol. v. 1832, p. 682. Africae Australis.' 

7* Leuckart quotes Meinecke " Quoted by Trimen, ' Transact. 

(Wagner, ' Handworterbuch der Ent. Soc' vol. v. part iv. 1866, p. 330. 
Phys.' B. iv. 1853, s. 775) that '* ' Transact. Liun. Soc' vol. xxv. 

the males of Butterflies are three p. 37. 

Chap. VIII. Proportion of the Sexes. 251 

here add, that in Hyperytlira, a genus of moths, Guenee says, that 
from four to five females are sent in collections from India for one 

When this subject of the proportional numbi^rs of the sexes of insects 
was brought before the Entomological Society,'" it was generally 
admitted that the males of most Leiiidoptera, in the adult or ima^io 
state, are caugijt in greater numbers than the females : but this fact 
was attributed by various observers to the more retiring habits of the 
females, and to the males emerging earlier from the cocoon. This 
latter circumstance is well known to occur with most Lepidoptcra. ns 
well as with other insects. So that, as M. Pcr.-^onnat remarks, the 
males of the domesticated Bombyx Yamamai, aie useless at the begin- 
ning of the Season, and the females at the end, from the want of 
mates.*" I cannot, however, persuade myself that these causes suffice to 
explain tl.e great excess of males, in the above cases of ccrtnin butter- 
flies 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 ho has reared them on a huge scale from the 
caterpillar state, he is convinced that the females are the liiore 
numerous. Several entomologists concur in this view. Mr. Double- 
day, however, and some others, take an opposite view, and are con- 
vinced that they have reared from tlie eggs and caterpillars a larger 
proportion of males than of females. 

Besides the more active habits of the males, their earlier emergence 
from the cucoon, and in some cases their frequenting more open 
stations, other causes may be assigned for an apparent or real difference 
in the propnrtional numbers of the sexes of Lepidoptera, when cap- 
tured in the imago state, and when reared from the egg or caterpillar 
state. I hear from Professor Canestrini, that it is believed by many 
breeders in Italy, that tiie 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 caterpilliir is la'ger 
than the male, and. a collector would naturally choose the finest 
specimens, and thus unintentionally collect a larger number of females. 
Three collectors have told me that this was their practice ; but Dr. 
Wallace is sure that most collectors take all the specimens which they 
can find of the rarer kinds, which alone are worth the trouble of 
rearing. Birds when surrounded by caterpillars would probably 
devour the largest ; and Professor Canestrini inlbrms me that in Italy 
some breeders believe, though on insufficient evidence, that in the first 
broods of the Ailanthus siik-moth, the wasps destroy a larger number of 
the female than of the male caterpillars. Dr. Wallace further remarks 
that female caterpillars, from being larger than the males, require 
more time for their development, and consume more food and mois- 
ture ; and thus they would be exposed during a longer time to 
danger from ichneumons, birds, &c., and in times of scarcity would 
perish in greater numbers. Hence it appears quite possible that 

^^ * Proc. Eutomolog. Soc' Feb. ' Proc. Eat. Soc' 3rd series, vol. v. 
I7th, 1868. 1867, p. 487. 

8f Quoted by Dr. Wallace in 

252 T J le Descent of Man, Pakt II. 

in a fctate of nature, fewer female LepidoptDra may reach maturity 
tiian males ; and for our special object we are concerned with their 
relative numbers at maturity, when the sexes are leady to propagate 
their land. 

The manner in which Iho males of certain moths congregjate in 
extraordinary numbers round a single female, apparently indicates a 
great excess of males, though this fact may perhaps bo accounted for 
by ihe earlier emergence of the males from their cocoons. Mr. 
Stainton informs me that from twelve to twenty males, may often be 
seen congregattd round a female Elachida rufocinerea. It is well 
known that if a virgin Lasiocampa quercus or Saiurnia carpiiti 
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 htr. Mr. 
Doubleday believes that he has seen from iifty to a hundred males of 
both these species attracted in the course of a single day by a ft male 
in confinement. In the Isle of Wight Mr. Trimen exposed a box 
in which a female of the Lasiocampa hid. been confined on the 
previous day, and five males soon endeavoured to gain admittance. 
In Australia, M. Yerreuux, 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. Staudinger's ®- litt 
of Lepidoptera, which gives the prices of the males and females of 
300 species or well-marked varieties of butterflies (Ehopalocera). The 
prices for both sexes of the very common species are of course the same ; 
but in 114 of the rarer species they ditier; 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 2000 species or varieties of moths 
(Heterocem) are catalogued, those with wingless females being here 
excluded on account of the difference in habits between the two sexes : 
of these 2000 species, 141 differ in price according t) i-ex, the males 
of 130 being cheaper, and those of oirly 11 being dearer than the 
females. The average price of the males of the 130 species, to that of 
the females, is as lOu to 143. With respect to the buttertiies in this 
priced litt, Mr. Doubleday thinks (and no man in England has had 
more experience), that there is nothing in the habit:, of the species 
which tan account for the difference in the prices of the two sexes, 
and that it Ciin be accounted for only by an excess in the number of 
the malts. But I am bound to add that Dr. Staudinger informs me, 
that he is h'mself of a different opinion. He thinks that the less active 
habits of the females and the earlier emergence of the males will 
account for his collectors securing a larger number of males than 
of females, and consequently for the lower prit-es of the former. With 
respect to specimens rtared from the caterpillar-state. Dr. Staudinger 
believes, as previously stated, that a greater number of females than of 
males die whilst confined in the cocoons. He adds that with certain 
species one sex seems to preponderate over the oth( r during certain 

Of direct observations on the sexes of Lepidoptera, reared either 

'^ Blanchard, ' Me'taraorphoses, ^^ ' Lepidopteren - Doubletten 

Moeurs des lasectes,' 1868, pp. 225- Liste,' Berlin, Ko. x. 1866. 

Chap. VII I. 

Propo7'tion of the Sexes. 


from eggs or caterpillars, I have received only the few following 

Males. ! Females. 

The Rev. J. Hellins*^ of Exeter reared, during 1868,|i 

imagos of 73 species, which consisted of. . ./j 
Mr. Albert Jones of Eltham reared, during 1868,^ 

imagos of 9 species, which consisted of . . . )\ 
During 18G9 he reared imagos from 4 species, con-i! 

sitting of /I 

Mr. Buckler of Emsworth, Hants, during 1869,11 

reared imagos from 74: species, consisting of. . J 1 
Dr. Wallace of Colchester reared from one brood of ll 

Bombyx cynthia j i 

Dr. Wallace raised, from cocoons of Bombyx Pernyin 

sent from China, during 1869 jj 

Dr. Wallace raised, during 1868 and 1869, from twolj 

lots of cocoons of Bombyx yama-mai . . .Jl 


153 I 

159 I 

114 j 

ISO ; 



934 I 





So that in these eight lots of cocoons and eggs, males were produced 
in excess. Taken together the proportion of males is as \1tl 
to 100 females. Bat the numbers are hardly large enough to be 

On the whole, from these various sources of evidence, all pointing 
in the same direction, I infer that with most species of Lepidopteia, 
the mature males generally exceed the females in number, whatever 
the proportions may be at their first emergence from tlie o.^^^. 

\s\\\\ reference to the other Orders of insects, I have been able 
to collect very little reliable information. With the stag-l^ee le 
{Lucaiuis cervus) "tlie males appear to be much more numerous 
"than the females;" but when, as Cornelius remarked during 18(37, 
sin unusual number of these beetles appeared in one i)art of C'erinany, 
the females appeared to exceed the males as six to one. With one of 
the Elateridae, the males are said to be much more numerous than the 
females, and "two or thiee are often found united with one female ;^^ 
" so that here polyandry seems to prevail." With Siagonium (!St iphy- 
linidoe), in which the males are furnished with horns, " t .e females are 
" far more numerous than the opposite sex." Mr. Janson stated at the 
Entumological Society that the females of the btrk- feeding Tomicns 
villosus are so common as to be a plague, whilst the males are so rare 
jis to be hardly known. 

'^ 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. 

** Giinther's ' Record of Zoo- 
logical Literature,' 1867, p. 260. 
On the excess of female Liicanus, 
ibid. p. 250. On the males of Luca- 
nus in England, Westwood, 'Modern 
Class, of Insects,' vol. i. p. 187. On 
the Siagouium, ibid. p. 172. 

254 1^^^ Desce7it of Man. Part II. 

It is liardly worth while saymg anything about the proportion of 
the sexes in certain spe 'ies and even groups of insects, for the males 
are unknown or very rare, and the females are parthenogenetic, that 
is, fertile without sexual rmion ; examples of this are afforded by 
several of the Cynipida^.*^ In all the gall-making Cynipidfe known 
to INIr. Walth, the females are four or live times as numerous as the 
males ; and so it i.s, as he informs me, with the gall-making Cecidomyiire 
(Diptera). With some common i-pecies of Saw-flies (Tenthredinai) 
Mr. F. Smith has reared hundreds of specimens from larvae of ail 
sizes, but has never reared a single male : c^n the other hand, Curtis 
say:<,*^ that with certain species (Athalia), bred by him, the males were 
t(» the females as six to one; whilst exactly the reverse occurred with 
the matiue insects of the same species caught in the fields. In the 
family of Bees, Hermann iMiiller.*^ collected a large number of 
specimens of mfiny s| ecies, and reared others from tl.e cocouns, and 
counted the texes. He found thut the males of some species gieatly 
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 
comme.'icement ,ot" the breeding seaton practically in excess. Miiller 
also observed that the relative number of the two sexes in s ^me 
species diftered much in different localities. But as H. Miiller has 
himself remarked to me, these remarks must be received with 
some caution, as one sex might more easily escape observation than 
the other. Thus his brother Fritz INIiiller has noticed in Brazil that 
the two sexes of the same species of bee sometimes frequent different 
kinds of lluwers. "With respect to the Orthoptera, I know hardly 
anything about the relative number cf the sexe^ : Korte,®^ however, 
says that out of 500 locusts which he examine 1, the males were to 
the females as five to six. With the Neuroptera, Mr. Walth states 
that in many, but by no means in all the species of the Odonatous 
group, there is a great overplus of males : in thg genus Heta^rina, also, 
the males are generally at least four times as numerous as the females. 
In certaiii species in the genus Gomphus the males are equally in 
excess, whilbt in two other spe 'ies, the females are twice or thrice 
as numerous as the males. In some European species of Psocus 
thousands of females may be collected without a single male, whilst 
with oilier species of the same genus both sexes are common,^^ In 
England, Mr. ]\IacLachlan has captured hundreds of the female 
Apatania muliebris, but has never seen t!,e male; and of Boreus 
hyfrtKilis on\j four or five males have been seen here."** With m<;8t 
of tin se species (excepting the Tenthredinre) 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 ti.e other Classes of the Articulata I have been able to collect still 

8^ Walsh, in 'The American En- derhenschrecke,' 1828, p. 20. 

tomologist,' vol. i. 1869, p. 103. *® ' Observations on X. American 

F. Smith, 'Record of Zoological Neuroptera,' by H. Hagen and B. D. 

Literature,' 1867, p. 328. Walsh, ' Proc. Ent. Soc. Phila- 

'"' ' Farm Insects,' pp. 45-46. delphia,' Oct. 1863, pp. 168, 223, 

*' * Anwendung der Darwinschen 239. 

Lehre Verb. d. n. V. Jahrg. x.xiv.' ^° ' Proc. Ent. Soc. London,' Feb. 

«8 'Die Strich, Zuir oder Wan- 17,1868. 

Chap. VIII. Proportion of the Sexes. 255 

loss information. With Spiilers, Mr. Blackwall, who has carefully 
attended to this class during many years, writes to me that the male's 
from their more erratic habits are more commonly seen, and therefore 
appeur more numerous. This is actually the case with a few species ; 
but he mentions several species in six genera, in wiiich the females 
ap[)ear to be much more numerous than the males.**' 'I'he small size of 
the males in comparison with the females (a peculiarity which is some- 
times carried to an extreme degree), and their widely ditierent appear- 
ance, may account in some instances for their rarity in collections.''^ 

Some of the lower Crustaceans ai-e able to propigate their kind 
nsexually, and this v/ill account for the extreme larity of the males : 
thus Von SiebokP^ carefully examined no less than 1:3,000 specimens of 
Apus from twenty-one localities, and amongst these he found only 
319 males. AV^itii some other forms (as Tanais and Cypris), as Fritz 
Miillt-r 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 
Diastylidc-e and of Cypridina on the shores of Brazil; thus witli a 
species in the latter genus, (33 specimens caught the same day included 
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, n;tmely a Celasimus, Fritz Miiller 
found the males to be more numerous than the females. According 
to the Inrge 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 jwwers. 
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 Yelderslcy 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 producing twins ; and concerning the above 
tendency a good authority, Mr. J. Downing, has communicated 
to me facts which seem to prove that this does occur in certain 
families of short-horn cattle. Col. Marshall ^^ has recently found 
on careful examination that the Todas, a hill-tribe of India, 

^* Another great authority with 0. P. Cambridge, as quoted in 
respect to this class, Prof. Thorell of 'Quarterly Journal of Science,' 
Upsala (' On European Spiders,' 18G8, p. 429. 

1869-70, part i. p. 205) speaks as if ^^ i Beitrage zur Parthenogenesis,' 

female spiders wei'e generally com- p. 174. 
moner than the males. 9* * The Todas,' 1873, pp. 100, 

»2 See, on this subject, Mr, 111, 194, 196, 

256 The Descent of Man. Part II. 

consist of 112 males and 84 females of all ages— that is in a ratio 
of 133-3 males to 100 females. The Todas, who are polyandrous 
in their marriages, during former times invariably practised 
female infanticide ; bnt this practice has now been discontinued 
for a considerable period. Of the children born within late years, 
the males are more numerous than the females, in the proportion 
of 121: to 100. Colonel Marshall accounts for this fact in the 
following ingenious manner. " Let us for the purpose of illustra- 
" tion take tln'ee families as I'epresenting an average of the 
" entire tribe ; say that one mother gives birth to six daughters 
'* and no sons ; a second mother has six sons only, whilst the 
" third mother has three sons and three daughters. The first 
" mother, following the tribal custom, destroys four daughters 
" and preserves two. The second retains her six sons. The third 
" kills two daughters and keeps one, as also her three sons. We 
" have then from the three families, nine sons and three daughters, 
" with which to continue the breed. But whilst the males 
" belong to families in which the tendency to produce sons is 
" great, the females are of those of a converse inclination. Thus 
" the bias strengthens with each generation, until, as we find, 
" families grow to have habitually more sons than daughters." 

That this result would follow from the above form of infanticide 
seems almost certain ; that is if we assume that a sex-producing 
tendency is inherited. But as the above numbers are so ex- 
tremely scanty, I have searched for additional evidence, but 
cannot decide whether wliat I have found is trustworthy ; 
nevertheless the facts are, i)erhaps, worth giving. The Maories of 
New Zealand have long practised infanticide ; and Mr. Fenton^^ 
states that he " has met with instances of women who have de- 
" stroyed four, six, and even seven children, mostly females. 
" However, the universal testimony of those best qualified to 
" judge, is conclusive that this custom has for many years been 
" almost extinct. Probably the year 1885 may be named as the 
" period of its ceasing to exist.'^ Now amongst the New Zea- 
landers, as with the Todas, male births are considerably in excess. 
Mr. Fenton remarks (p. 30), " One fact is certain, although the 
" exact period of the commencement of this singular condition of 
" the disproportion of the sexes cannot be demonstratively fixed, 
" it is quite clear that this course of decrease was in full opera- 
" tion during the years 1S30 to 1844, when the non-adult 
'' population of 1844 was being produced, and has continued 
" with great energy up to the present time." The following 
statements are taken from Mr. Fenton (jd, 26), but as the numbers 

^^ 'Aboriginal Inhabitants of New Zealand ; Government Report,' 1859, 
p. 36. 

Chap. VIII. Proportion of the Sexes. 257 

are not large, and as the census was not accurate, uniform 
results cannot be expected. It should be borne in mind in this 
and the following cases, that the normal state of every population 
is an excess of women, at least in all civilised countries, chiefly 
owing to the greater mortality of the male sex during youth, and 
partly to accidents of all kinds later in life. In 1858, the 
native population of New Zealand was estimated as consisting 
of 31,607 males and 21,303 females of all ages, that is in the 
ratio of 1303 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 uon-adidt females 142, that is in 
the ratio of 125*3 to 100. It may be added that in 1844, at 
which pariod female infanticide had only lately ceased, the 
nou-adult males in one district were 281, and the non-adult 
females only 191, that is in the ratio of 144-8 males to 100 females. 

In the Sandwich Islands, the males exceed the females in 
number. Infanticide was formerly practised there to a frightful 
extent, but was by no means confined to female infants, as 
is shewn by Mr. EUis,^'' and as I have been informed by Eishop 
Staley and the Eev. Mr. Coan. Nevertheless, another apparently 
trustworthy writer, Mr. Jarves,^^ whose observations apply to 
the whole archiiDelago, 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 
kno^vn to occur in other parts of the world, this statement is 
probable ; but must be received with much caution. The 
practice of infanticide ceased about the year 1819, when idolatry 
was abolished and missionaries settled in the Islands. A careful 
census in 1839 of the adult and taxable men and women in the 
island of Kauai and in one district of Oahu (Jarves, p. 404), 
gives 4723 males and 3776 females; that is in the ratio of 
125'08 to 100. At the same time the number of males under 
fourteen years in Kauai and under eighteen in Oahu was 1797, 
and of females of the same ages 1429 ; and here we have the 
ratio of 12575 males to 100 females. 

In a census of all the islands in 1850,^*^ the males of all ages 

^^ 'Narrative of a Tour through ^* This is given in the Rev. H. T. 

Hawaii,' 1826, p. 298. Cheever's ' Life in the Sandwich Is- 

»^ ' History of the Sandwich lands,' 1851, p. 277. 
Islands,' 1843, p. 93. 


The Descent of Man. 

Paet II. 

amount to 36,272, and the females to 33,128, or as 109-49 to 
100. The males under seventeen years amounted to 10,773, and 
the females under the same age to 9593, or as 112*3 to 100. 
From the census of lfe72, the proportion of males of all ages 
(including half-castes) to females, is as 125*36 to 100. It must 
be borne in mind that all these returns for the Sandwich 
Islands give the proportion of living males to living females, 
and not of the births ; and judging from all civilised countries 
the proportion of males would have been considerably higher it 
the numbers had referred to births.^^ 

From the several foregoing cases we have some reason to 
believe that infanticide practised in the manner above explained, 
tends to make a male-producing race ; but I am far from sup- 
posing that this practice in the case of man, or some analogous 
process with other species, has been the sole determining cause 
of an excess of males. There may be some unknown law leading 
to this result in decreasing races, which have already become 
somewhat infertile. Besides the several causes previously 

^^ Dr. Coulter, in describing 
(' Journal R. Geograph. Soc.,' vol. 
V. 1835, p. 67) the state of Cali- 
fornia about the year 1830, says 
that the natives, reclaimed by the 
Spanish missionaries, have nearly 
all perished, or are perishing, al- 
though well treated, not driven 
from their native land, and kept 
from the use of spirits. He at- 
tributes this, in great part, to the 
undoubted fact that the men greatly 
exceed the women in number ; but 
he does not know whether this is 
due to a failure of female offspring, 
or to more females dying during 
early youth. The latter alternative, 
according to all analogy, is very 
improbable. He adds tiiat " in- 
" fanticide, properly so called, is 
" not common, though very fre- 
" quent recourse is had to abor- 
" tion." If Dr. Coulter is correct 
about infjinticide, this case cannot 
be advanced in support of Col. 
Marshall's view. From the rapid 
decrease of the reclaimed natives, 
we may suspect that, as in the 
cases lately given, their fertility 
has been diminished from changed 
habits of life. 

I had hoped to gain some light 

on this subject from the breeding 
of dogs; inasmuch as in most breeds, 
with the exception, perhaps, of 
greyhounds, many more female 
puppies are destroyed than males, 
just as with the Toda infants. Mr. 
Cupples assures me that this is 
usual with Scotch deer-hounds. 
Unfortunately, I know nothing 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 from 
enquiries made from many breeders, 
it seems that the females are 
in some respects more esteemed, 
though otherwise troublesome ; and 
it does not appear that the female 
puppies of the best-bred dogs are 
systematically destroyed more than 
the males, though this does sometimes 
take place to a limited extent. There- 
fore 1 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 (;here is any 
difference, the females are slightly 
in excess. 

Chap. VIII. Proportion of tJie Sexes. 259 

alluded to, the greater facility of parturition amongst savages, 
and the less consequent injury to their male infants, would 
tend to increase the proportion of live-born males to females. 
There does not, however, seem to be' any necessary connection 
between savage life and a marked excess of males ; that is if we 
may judge by the character of the scanty offspring of the lately 
existing Tasmanians and of the crossed offspring of the Tahitians 
now inhabiting Norfolk Island. 

As the males and females of many animals differ somewhat in 
habits and are exposed in different degrees to danger, it is 
probable that in many cases, more of one sex than of the other 
are habitually destroyed. But as far as I can trace out the com- 
plication of causes, an indiscriminate though large destruction 
of either sex would not tend to modify the sex-producing power 
of the species. With strictly social animals, such as bees or ants, 
which produce a vast number of sterile and fertile females in 
comparison with the males, and to whom this preponderance is 
of paramount importance, we can see that those communities 
would flourish best which contained females having a strong 
inherited tendency to produce more and more females ; and in 
such cases an unequal sex-producing tendency would be ulti- 
mately gained through natural selection. With animals living 
in herds or troops, in which the males come to the front and 
defend the herd, as with the bisons of North America and certain 
baboons, it is conceivable that a male-producing tendency might 
be gained by natural selection ; for the individuals of the better 
defended herds would leave more numerous descendants. In 
the case of mankind the advantage arising from having a pre- 
ponderance of men in the tribe is supposed to be one chief cause 
of the practice of female infanticide. 

In no case, as far as we can see, would an inherited tendency 
to produce both sexes in equal numbers or to produce one sex 
in excess, be a direct advantage or disadvantage to certain 
individuals more than to others ; for instance, an individual 
with a tendency to produce more males than females would not 
succeed better in the battle for life than an individual with an 
opposite tendenc}'" ; and therefore a tendency of this kind could 
not be gained through natural selection. Nevertheless, there are 
certain animals (for instance, fishes and cirripedes) in which two 
or more males appear to be necessary for the fertilisation of the 
female ; and the males accordingly largely preponderate, but it 
is by no means obvious how this male-producing tendency could 
have been acquired. I formerly thought that when a tendency 
to produce the two sexes in equal numbers was advantageous to 
the species, it would follow from natural selection, but I now 

26o The Descent of Man. Part II. 

see that the whole problem is so intricate that it is safer to leave 
its solution for the future. 


Secondary Sexual Characters in the Lower Classes of 
THE Animal Kingdom. 

These characters absent in the lowest classes — Brilliant colours — MoUusca 
— Annelids — Crustacea, secondary sexual characters strongly developed ; 
dimorphism; colour; characters not acquired before maturity — Spiders, 
sexual colours of; stridulation by the males — Myriapoda. 

With animals belonging to the lower classes, the two sexes 
are not rarely united in the same individual, and therefore 
secondary sexual characters cannot be developed. In many 
cases where the sexes are separate, both are permanently at- 
tached to some support, and the one cannot search or struggle 
for the other. Moreover it is almost certain that these animals 
have too imperfect senses and much too low mental powers, to 
appreciate each other's beauty or other attractions, or to feel 

Hence in these classes or sub-kingdoms, such as the Protozoa, 
Coelenterata, Echinodermata, Scolecida, secondary sexual cha- 
racters, of the kind which we have to consider, do not occur ; and 
this fact agrees with the belief that such characters in the 
higher classes have been acquired through sexual selection, 
which depends on the will, desire, and choice of either sex. 
Nevertheless some few apparent exceptions occur ; thus, as I 
hear from Dr. Eaird, the males of certain Entozoa, or internal 
parasitic worms, differ slightly in colour from the females ; but 
we have no reason to suppose that such differences have been 
augmented through sexual selection. Contrivances by which the 
male holds the female, and which are indispensable for the 
propagation of the species, are independent of sexual selection, 
and have been acquired through ordinary selection. 

Many of the lower animals, whether hermaphrodites or with 
separate sexes, are ornamented with the most brilliant tints, or 
are shaded and striped in an elegant manner ; for instance, many 
corals and sea-anemones (Actiniae), some jelly-fish (Medusae, 
Porpita, &c.), some Planarise, many star-fishes. Echini, Ascidians, 
&c. ; but we may conclude from the reasons already indicated, 
namely the union of the two sexes in some of these animals, the 
permanently affixed condition of others, and the low mental 
powers of all, that such colours do not serve as a sexual 
attraction, and have not been acquired through sexual selection. 

Chap. IX. Sexual Selection. 26 1 

It should be borne in mind that in no case have we suffi- 
cient evidence that colours have been thus acquired, ex- 
cept where one sex is much more brilliantly or conspicuously 
coloured than the other, and where there is no difference 
in habits between the sexes sufficient to account for their 
different colours. But the evidence is rendered as complete 
as it can ever be, only when the more ornamented indivi- 
duals, almost always the males, voluntarily display their 
attractions before the other sex ; for we cannot believe that such 
display is useless, and if it be advantageous, sexual selection 
will almost inevitably follow. AVe may, however, extend this 
conclusion to both sexes, when coloured alike, if their colours are 
plainly analogous to those of one sex alone in certain other 
species of the same group. 

How, then, are we to account for the beautiful or even 
gorgeous colours of many animals in the lowest classes? It 
appears doubtful whether such colours often serve as a protec- 
tion ; but that we may easily err on this head, will be admitted 
by every one who reads Mr. Wallace's excellent essay on this 
subject. It would not, for instance, at first occur to auy one 
that the transparency of the Medusae, or jelly-fishes, is of the 
highest service to them as a protection; but when we are 
reminded by Hackel that not only the medusae, but many 
floating mollusca, crustaceans, and even small oceanic fishes 
partake of this same glass-like appearance, often accompanied 
by prismatic colours, we can hardly doubt that they thus 
escape the notice of pelagic birds and other enemies. M. 
Girard is also convinced ^ that the bright tints of certain 
sponges and ascidians serve as a protection. Conspicuous 
colours are likewise beneficial to many animals as a warning to 
their would-be devourers that they are distasteful, or that they 
possess some special means of defence ; but this subject will be 
discussed more conveniently hereafter. 

We can, in our ignorance of most of the lowest 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 colour is finer than that 
of arterial blood; but there is no reason to suppose that the 
colour of the blood is in itself any advantage; and though it 
adds to the beauty of the maiden's cheek, no one will pretend 
that it has been acquired for this purpose. So again with many 
animals, especially the lower ones, the bile is richly coloured ; 
thus, as I am informed by Mr. Hancock, the extreme beauty of 
the Eolidae (naked sea-slugs) is chiefly due to the biliary glands 
' 'Archives dc Zoolog. Exper.,' Oct. 1872, p. 563. 

262 The Descejit of Man, Part U. 

being seen through the translucent integuments — this beauty 
being probably of no service to these animals. The tints of the 
decaying leaves in an American forest are described by every 
one as gorgeous; yet no one supposes that these tints are 
of the least advantage to the trees. Bearing in mind how many 
substances closely analogous to natural organic compounds have 
been recently formed by chemists, and which exhibit the most 
splendid colours, it would have been a strange fact if substances 
similarly coloured had not often originated, independently of 
any useful end thus gained, in the complex laboratory of living 

The sub-kingdom of the Mollusca. — Throughout this great 
division of the animal kingdom, as far as I can discover, 
secondary sexual characters, such as we are here considering, 
never occur. Nor could they be expected in the three lowest 
classes, namely in the Ascidians, Polyzoa, and Brachiopods 
(constituting the Molluscoida of some authors), for most of 
these animals are permanently affixed to a support or have their 
sexes united in the same individual. In the Lamellibranchiata, 
or bivalve shells, hermaphroditism is not rare. In the next 
higher class of the Gasteropoda, or univalve shells, the sexes are 
either united or separate. But in the latter case the males 
never possess special organs for finding, securing, or charming 
the females, or for fighting with other males. As I am informed 
by Mr. Gwyn Jeffreys, the sole external difference between the 
sexes consists in the shell sometimes differing a little in form ; 
for instance, the shell of the male periwinkle {LUtorina littorea) 
is narrower and has a more elongated spire than that of the 
female. But differences of this nature, it may be presumed, are 
directly connected with the act of reproduction, or with the 
development of the ova. 

The Gasteropoda, though capable of locomotion and furnished 
with imperfect eyes, do not appear to be endowed with sufficient 
mental powers for the members of the same sex to struggle 
together in rivalry, and thus to acquire secondary sexual 
characters. Nevertheless with the pulmoniferous gasteropods, or 
land-snails, the pairing is preceded by courtship; for these 
animals, though hermaphrodites, are compelled by their structure 
to pair together. Agassiz remarks,^ " Quiconque a eu I'occasion 
" d'observer les amours des lima9ons, ne saurait mettre en doute 
" la seduction deployee dans les mouvements et les allures qui 
" preparent et accomplissent le double embrassement de ces 
" hermaphrodites." These animals appear also susceptible of 
some degree of permanent attachment : an accurate observer, 
* ' De I'Espece et de la Class.' &c., 1869, p. 106. 

Chap. IX. 

Molluscs. 263 

Mr. Lonsdale, informs me that he placed a pair of land-snails, 
{Hdix j>omatia), one of which was weakly, into a small and ill- 
provided garden. After a short time the strong and healthy 
individual disappeared, and was traced by its track of slime 
over a wall into an adjoining well-stocked garden. Mr. 
Lonsdale concluded that it had deserted its sickly mate; but 
after an absence of twenty-four hours it returned, and apparently 
communicated the result of its successful exploration, for both 
then started along the some track and disappeared over the 


Even in the highest class of the Mollusca, the Cephalopoda or 
cuttlefishes, in which the sexes are separate, secondary sexual 
characters of the present kind do not, as far as I can discover, 
occur. This is a surprising circumstance, as these animals 
possess highly-developed sense-organs and have considerable 
mental powers, as will be admitted by every one who has watched 
their artful endeavours to escape from an enemy.^ Certain 
Cephalopoda, however, are characterised by one extraordinary 
sexual character, namely, that the male clement collects within 
one of the arms or tentacles, which is then cast off, and clinging 
by its sucking-discs to the female, lives for a time an independent 
life. So completely does the cast-off arm resemble a separate 
animal, that it was described by Cuvier as a parasitic worm 
under the name of Plectocolyle. But this marvellous structure 
may be classed as a primary rather than as a secondary sexual 

Although with the Mollusca sexual selection does not seem to 
have come into play; yet many univalve and bivalve shells, 
such as volutes, cones, scallops, &c., are beciutifully coloured 
and shaped. The colours do not appear in most cases to be of 
any use as a protection ; they are probably the direct result, as 
in the lowest classes, of the nature of the tissues ; the patterns 
and the sculpture of the shell depending on its manner of 
growth. The amount of light seems to be influential to a certain 
extent; for although, as repeatedly stated by Mr. Gwyn Jeffreys, 
the shells of some species living at a profound depth are brightly 
coloured, yet we generally see the lower surfaces, as well as the 
parts covered by the mantle, less highly-coloured than the 
upper and exposed surfaces.-* In some cases, as with shells 

3 See, for instance, the account influence of light on the colours of 

which I have given in my 'Journal a I'rondescent incrustation, de- 

of Researches,' 1845, p. 7. posited by the surf on the coast- 

* I have given (' Geolog. Obser- rocks of Ascension, and formed by 

vations on Volcanic Islands,' 18+4, the solution of triturated sea-shells, 
p. 53) a curious instance of the 

264 The DesccJit of Man. Fart II. 

living amongst corals or briglitly-tinted sea-weeds^ the bright 
colours may serve as a protection.^ But that many of the nudi- 
brancli mollusca, or sea-slugs, are as beautifully coloured as any 
shells, may be seen in Messrs. Alder and Hancock's magnificent 
work ; and from information kindly given me by Mr. Hancock, 
it seems extremely doubtful whether these colours usually serve 
as a protection. With some species this may be the case, as with 
one kind which lives on the green leaves of algse, and is itself 
bright-green. But many brightly-coloured, white or otherwise 
conspicuous species, do not seek concealment ; whilst again some 
equally conspicuous species, as well as other dull-coloured kinds, 
live under stones and in dark recesses. So that with these nudi- 
branch molluscs, colour apparently does not stand in any close 
relation to the nature of the places which they inhabit. 

These naked sea-slugs are hermaphrodites, yet they pair 
together, as do land-snails, many of which have extremely 
pretty shells. It is conceivable that two hermaphrodites, 
attracted by each other's greater beauty, might unite and leave 
offspring which would inherit their parents' greater beauty. 
But with such lowly-organised creatures this is extremely 
improbable. Nor is it at all obvious how the offspring from the 
more beautiful pairs of hermaphrodites would have any ad- 
vantage over the offspring of the less beautiful, so as to increase 
in number, unless indeed vigour and beauty generally coincided. 
We have not here the case of a number of males becoming 
mature before the females, with the more beautiful males 
selected by the more vigorous females. If, indeed, brilliant 
colours were beneficial to a hermaphrodite animal in relation 
to its general habits of life, the more brightly-tinted individuals 
would succeed best and would increase in number ; but this 
would be a case of natural and not of sexual selection. 

Sub-kingdom of the Vermes: Class, Annelida (or Sea-ivorms). — 
In this class, although the sexes, when separate, sometimes 
differ from each other in characters of such importance that they 
have been placed under distinct genera or even families, yet the 
differences do not seem of the kind which can be safely at- 
tributed to sexual selection. These animals are often beauti- 
fully coloured, but as the sexes do not differ in this respect, we 
are but little concerned with them. Even the Nemertians, 
though so lowly organised, " vie in beauty and variety of 
" colouring with any other group in the invertebrate series;" yet 

^ Dr. Morse has lately discussed ' Proc. Boston Soc. of Nat. Hist.' 
this subject in his paper on the vol. xiv., April, 1871. 
Adaptive Coloration of Mollusca, 

Chap. IX. Crustaceaiis, 265 

Dr. Mcintosh" cannot discoTcr that these colours are of any 
service. The sedentary annelids become dnller-colonred, ac- 
cording to M. Quatrefages/ after the period of reproduction ; and 
this I presume may be attributed to their less vigorous condition 
at that time. All these-worm-like animals apparently stand too 
low in the scale for the individuals of either sex to exert any 
choice in selecting a partner, or for the individuals of the same 
sex to struggle together in rivalry. 

Suh-hingdom of the Arthropoda : Class, Crustacea, — In this great 
class we first meet with undoubted secondary sexual characters, 
often developed in a remarkable manner. Unfortunately the 
habits of crustaceans are very imx^erfectly known, and we cannot 
explain the uses of many structures i3eculiar to one sex. With the 
lower i^arasitic species the males are of small size, and they 
alone are furnished with perfect swimming-legs, antennse and 
sense-organs ; the females being destitute of these organs, with 
their bodies often consisting of a mere distorted mass. But 
these extraordinary differences between the two sexes are no 
doubt related to their widely different habits of life, and con- 
sequently do not concern us. In various crustaceans, belonging to 
distinct families, the anterior antennae are furnished with Xjeculiar 
thread-like bodies, which are believed to act as smelling-organs, 
and these are much more numerous in the males than in the 
females. As the males, without any unusual development of 
their olfactory organs, would almost certainly be able sooner or 
later to find the females, the increased number of the smelling- 
threads has probably been acquired through sexual selection, by 
the better provided males having been the more successful in 
finding partners and in producing offspring. Fritz Miiller lias 
described a romarkable dimorphic species of Tanais, in which the 
male is represented by two distinct forms, which never graduate 
into each other. In the one form the male is furnished with 
more numerous smelling-threads, and in the other form with 
more powerful and more elongated chelse or pincers, which serve 
to hold tlie female. Fritz Miiller suggests that these differences 
between the two male forms of the same species may have 
originated in certain individuals having varied in the number of 
the smelling-threads, whilst other individuals varied in the 
fthape and size of their chelae ; so that of the former, those which 
were best able to find the female, and of the latter, those v/hich 

• See his beautiful monograph on ^ See M. Perrier, ' I'Origine de 

* British Annelids,' part i. 1873, I'Homme d'apres Darwin,' ' Kevue 
p. 3. Scientifique,' Feb. 1873, p. 8G6. 


The Descent of Man. 

Part II. 

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 antennsB 
of the female. In the male the 
modified antenna is either swollen in 
the middle or angularly bent, or 
converted (fig. 4) into an elegant, 
and sometimes wonderfully complex, 
prehensile organ.^ It serves, as I hear 
from Sir J. Lubbock, to hold the 
female, and for this same purpose one 
of the two posterior legs (6) on the 
same side of the body is converted 
into a forceps. In another family the 
inferior or . posterior antennsB are 
'' curiously zigzagged " in the males 

In the higher crustaceans the an- 
terior legs are developed into chelae 
or pincers; and tlicse are generally 
larger in the male than in the female, 
— so much so that the market value of 
the male edible crab (^Caiicer jpagurus), 
according to IMr. C. Spence Bate, is 
five times as great as that of the fe- 
male. In many species the chelse are 
of unequal size on the opposite side of 
the body, the right-hand one being, as 
I am informed by Mr. Bate, generally, 
though not invariably, the largest. This inequality is also often 
much greater in the male than in the female. The two chelae 
of the male often differ in structure (figs. 5, 6, and 7), the 
smaller one resembling that of the female. What advantage is 
gained by their inequality in size on the opposite sides of the 

4. LabWocera Darwinii 
(from Lubbock). 

a. Part of right anterior an- 

tenna of male, forming a 
prehensile organ. 

b. Posterior pair of thoracic legs 

of male. 

c. Ditto of temale. 

* * Facts and Arguments for 
Darwin,' English translat. 1869, p. 
20. See the pi-evious discussion on 
the olfactory threads. Sars has 
described a somewhat analogous 
case (as quoted in * Nature,' 1870, 
p. 455) in a Norwegian crustacean, 
the Poiitoporeia affinis. 

^ See Sir J. Lubbock in ' Annals 

and Mag. of Nat. Hist.' vx)l. xi. 
1853, pi. i. and x. ; and vol. xii. 
(1853) pi. vii. See also Lubbock in 
'Transact. Ent. Soc' vol. iv. new 
series, 1856-1858, p. 8. With re- 
spect to the zig-zagged antennjE 
mentioned below, see Fritz Miiller, 
' Facts and Arguments for Darwin,' 
1869, p. 40, foot-note. 

Chap. IX. 



body, and by the inequality being much greater in the male than 
in the female ; and why, when they are of equal size, both aro 

Fig. 5. Anterior part of body of Callianassa (from Milne-Edwards), showing the un- 
equal and dififerently-coustructed right and left-hand chela? of the male. 

N.B— The artist by mistake has reversed the drawing, and made the left-hand chela 
the largest. 

Fig. 6. 
Fig. 7. 

Fig. 6. Fig. Y. 

Second leg of male Orchestia Tucuratinga (from Fritz MUller). 
Ditto of female. 

often much larger in the male than in the female, is not known. 
As 1 hear from Mr. Bate, the chelae are sometimes of such length 
and size that they cannot possibly be used for carrying food to the 
mouth. In the males of certain fresh-water prawns (Palsemon) 
the right leg is actually longer than the whole body.^° The 
gr3at size of the one leg with its chela3 may aid the male in 
fighting with his rivals; but this will not account for their 

*" See a paper by ^Ir. C. Spence 
Bate, with figures, in ' Proc. Zoolosj. 
See' 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 chelae 
of the higher crustaceans. 

268 T]ie Descent of Man. Part II. 

inequality in the female on the opposite sides of of the body. In 
Gelasimus, according to a statement quoted by Milne-Edwards," 
the male and the female live in the same bnrrow, and this 
shews that they pair ; the male closes the month of the burrow 
with one of its chelre, which is enormously developed ; so that 
here it indirectly serves as a means of defence. Their main use, 
however, is probably to seize and to secure the female, and this 
in some instances, as with Gammarus, is known to be the case. 
The male of the hermit or soldier crab {Fafiurus) for weeks 
together, carries about the shell inhabited by the female. ^^ The 
sexes, however, of the common shore-crab (Carcinus manas), 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 pincers of the male ; but as she is caught 
and carried about by the male before moulting, she could then be 
seized with impunity. 

Fritz Muller states that certain species of Melita are distin- 
guished from all other amphipods by the females having " the 
" coxal lamellae 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 develojDment of these hook-like 
processes has probably followed from those females which were 
the most securely held during the act of reproduction, having 
left the largest number of offspring. Another Brazilian amphi- 
pod (Oichestia 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 chelse.^^ As either chela would certainly 
suffice to hold the female, — for both are now used for this purpose, 
— the two male forms probably originated by some having varied 
in one manner and some in another ; both forms having derived 
certain special, but nearly equal advantages, from their differently 
shaped organs. 

It is not known that male crustaceans fight together for the 
possession of the females, but it is probably the case ; for with 
most animals when the male is larger than the female, he seems 
to owe his greater size to his ancestors having fought 
with other males during many generations. In most of the 
orders, especially in the highest or the Brachyura, the male is 
larger than the female ; the parasitic genera, however, in which 
the sexes follow different habits of life, and most of the Ento- 
mostraca must be excei)ted. The cheljB of many crustaceans are 

" *Hist. Nat. des Crust.' torn. ii. of S. Devon.' 
1837, p. 50. ^^ Fritz Miiller, ' Facts and Argu- 

>2 Mr. C. Spence Bate, * Brit. ments for Darwin,' 1869, pp. 25-28 
Assoc, Fourth Report on the Fauna 

Chap. IX. 



■weapons well adapted for fighting. Tluis when a Devil-crab 
{Portunus pubcr) was seen by a son of Mr. Bate fighting with a 
Carcinus mcenas, the latter was soon thrown on its back, and had 
every limb torn from its body. When several males of a Brazilian 
Gelasimns, 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 Carcmus 

Fig. 8. Orchestia Darwinii (from Fritz Miiller), showing the differently-constructed 
cheltB uf the two male forms. 

mcenas into *a pan of water, inhabited by a female which was 
paired with a smaller male ; but the latter was soon dispossessed. 

2/0 The Descent of Man. Part II. 

Mr. Bate adds, '' if they fought, the victory was a bloodless one, 
" for I saw 110 wounds." This same naturalist separated a male 
sand-skipper (so common on our sea-shores), Gammarus marmus, 
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 Avas put again into the same vessel ; and he then, after 
swimming about for a time, dashed into the crowd, and without 
any fighting at once took away his wife. This fact shews that 
in the Amphipoda, an order low in the scale, the males and 
females recognise each other, and are mutually attached. 

The mental powers of the Crustacea are i^robably 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 {Binjus 
latro), found on coral islands, which makes a thick bed of the 
picked fibres of the cocoa-nut, at the bottom of a deep burrow. 
It feeds on the fallen fruit of this tree by tearing off the husk, 
fibre by fibre ; and it always begins at that end where the three 
eye-like depressions are situated. It then breaks through one of 
these eyes by hammering with its heavy front pincers, and 
turning round, extracts the albuminous core with its narrow 
posterior pincers. But these actions are probably instinctive, so 
that they would be performed as well by a young animal as by 
an old one. The following case, however, can hardly be so con- 
sidered : a trustworthy naturalist, Mr. Gardner,^^ whilst watching 
a shore-crab (Gelasimus) making its burrow, threw some shells 
towards the hole. One rolled in, and three other shells remained 
within a few inches of the mouth. In about five minutes the 
crab brought out the shell which had fallen in, and carried it 
away to the distance of a foot ; it then saw the three other shells 
lying near, and evidently thinking that they might likewise roll 
in, carried them to the spot where it had laid the first. It 
would, I think, be difi&cnlt to distinguish this act from one 
performed by man by the aid of reason. 

Mr. Bate does not know of any well-marked case of difference 
of colour in the two sexes of our British crustaceans, in which 
respect the sexes of the higher animals so often differ. In some 
cases, however, the males and females differ slightly in tint, but 
Mr. Bate thinks not more than may be accounted for by their 
different habits of life, such as by the male wandering more 
about, and being thus more exposed to the light. Dr. Power 

** ' Travels in the Interior of 463, un account of the hiibits of the 
Brazil,' 1846, p. 111. I have given, Birgus. 
in my ' Joui-nal of Researches,' p. 

Chap. IX. Crustaceans. 2/1 

tried to distinguish by colour the sexes of the several species 
which inhabit the Mauritius, but failed, except with one species 
of Squilla, probably .S'. stylifera, the male of which is described as 
being" of a beautiful bluish-green," with some of the appendages 
cherry-red, whilst the female is clouded with brown and grey, 
" 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 colours. With Saphirina (an 
oceanic genus of Entomostraca), the males are furnished with 
minute shields or cell-hke bodies, which exhibit beautiful 
changing colours ; 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 by Fritz Miiller, that in the female of a 
Brazilian species of Gelasimus, the whole body is of a nearly 
uniform greyish-brown. In the male the posterior part of the 
cephalo-thorax is pure white, with the anterior part of a rich 
green, shading into dark brown ; and it is remarkable that these 
colours are liable to change in the course of a few minutes — the 
white becoming dirty grey or even black, the green " losing much 
" of its brilliancy." It deserves especial notice that the males do 
not acquire their bright colours until they become mature. They 
appear to be much more numerous than the females; they 
differ also in the larger size of their chelae. In some species of 
the genus, probably in all, the sexes pair and inhabit the same 
burrow. They are also, as we have seen, highly intelligent 
animals. From these various considerations it seems probable 
that the male in this species has become gaily ornamented in 
order to attract or excite the female. 

It has just been stated that the male Gelasimus does not 
acquire his conspicuous colours until mature and nearly ready 
to breed. This seems a general rule in the whole class in respect 
to the many remarkable structural differences between the sexes. 
We shall hereafter find the same law prevailing throughout the 
great sub-kingdom of the Vertebrata ; and in all cases it is 
eminently distinctive of characters which have been acquired 
through sexual selection. Fritz Miiller ^^ gives some striking 
instances of this law ; thus the male sand-hopper (Orchestia) 
does not, until nearly full grown, acquire his large claspers, 

*^ Mr. Ch. Fraser, in * Proc. Zoo- '* Claus, ' Die freilebenden Cope- 
log. Soc' 1869, p. 3. I am indebted poden,' 1863, s. 35. 
to Mr. Bate for Dr. Power's state- '^ ' Facts and Arguments,' &c., 
ment. p. 79. 

2/2 TJie Descent of Man. Part II. 

which are yery differently constructed from those of the female ; 
whilst young, his claspers resemble those of the female. 

Class, Arachnida (Spiders). — The sexes do not generally differ 
much in colour, but the males are often darker than the females, 
as may be seen in Mr. Blackwall's magnificent work.^** In some 
species, however, the difference is conspicuous : thus the female 
of Sjmrassus smaragdidus is dullish green, whilst the adult male 
has the abdomen of a fine yellow, with three longitudinal stripes 
of rich red. In certain species of Thomisus the sexes closely 
resemble each other, in others they differ much ; and analogous 
cases occur in many other genera. It is often difficult to say 
which of the two sexes departs most from the ordinary coloration 
of the genus to which the species belong ; but Mr. Blackwall 
thinks that, as a general rule, it is the male ; and Canestrini ^^ 
remarks that in certain genera the males can be specifically dis- 
tinguished with ease, but the females with great difficulty. I am 
informed by Mr. Blackwall that the sexes whilst young usually 
resemble each other ; and both often undergo gi-eat changes in 
colour during their successive moults, before arriving at maturity. 
In other cases the male alone appears to change colour. Thus 
the male of the above bright-coloured Sparassus at first re- 
sembles the female, and acquires his peculiar tints only when 
nearly adult. SjDiders are j)ossessed of acute senses, and exliibit 
much intelligence ; as is well known, the females often shew 
the strongest affection for their eggs, wliich they carry about 
enveloped in a silken web. The males search eagerly for the 
females, and have been seen by Canestrini and others to fight for 
possession of them. This same author says that the union of the 
two sexes has been observed in about twenty species ; and he 
asserts positively that the female rejects some of the males who 
court her, threatens them with open mandibles, and at last after 
long hesitation accepts the chosen one. From these several 
considerations, we may admit with some confidence that the 
well-marked differences in colour between the sexes of certain 
species are the results of sexual selection ; though we have not 
here the best kind of evidence, — the display by the male of his 
ornaments. From the extreme variability of colour in the male 
of some sjDecies, for instance of Theridion llneatum, it would 
appear that these sexual characters of the males have not as yet 
become well fixed. Canestrini draws the same conclusion from 

'* • A. History of the Spiders of ' Caratteri sessuali secondarii degli 

Great Britain,' 1861-G4-. For the Arachnidi,' in the 'Atti della See. 

fcllowiug facts, see pp. 77, 88, 102. Veneto-Trentiua di Sc. Nat. Padova, 

'^ This author has recentfy pub- vol. i. Fasc. 3, 1873. 
lishod a valuable essay on the 

Chap. IX. Spiders. 273 

the fact that the males of certain species present two forms, 
differing from each other in the size and length of their jaws ; and 
this reminds us of the above cases of dimorphic crustaceans. 

The male is generally much smaller than the female, sometimes 
to an extraordinary degree,-" and he is forced to be extremely 
cautious in making his advances, as the female often carries her 
coyness to a dangerous pitch. De Geer saw a male that " in the 
" midst of his preparatory caresses was seized by the object of 
" his attentions, enveloped by her in a web and then devoured, a 
" sight which, as he adds, filled him with horror and indignation." ^^ 
The Eev. 0. P. Cambridge ^^ accounts in the following manner 
for the extreme smalhiess of the male in the genus Nephila. 
" M. Vinson gives a gTaphic account of the agile way in which 
" the diminutive male escapes from the ferocity of the female, by 
" gliding about and playing hide and seek over her body and 
" along her gigantic limbs : in such a pursuit it is evident that 
" the chances of escape would be in favour of the smallest males, 
" while the larger ones would fall early victims ; thus gradually 
" a diminutive race of males would be selected, until at last they 
" would dwindle to the smallest possible size compatible with the 
" exercise of their generative functions, — in fact probably to the 
" size we now see them, i.e., so small as to be a sort of parasite 
" upon the female, and either beneath her notice, or too agile and 
" too small for her to catch without great difficulty." 

Westring has made the interesting discovery that the males 
of several species of Theridion^ have the power of making 
a stridulating sound, whilst the females are mute. The ap- 
paratus consists of a serrated ridge at the base of the abdomen, 
against wliich 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, 

-" Aug. Vinson (' Araneides des tion to Entomology,' vol. i. 1818, 

lies de la Reunion/ pi. vi. figs. 1 p. 280. 

and 2) gives a good instance of the ^^ 'Proc.Zoolog. Soc' 1871, p. 621. 

small size of the male, in Epeira ^s Jheridion (Asagena, Sund.) 

nigra. In this species, as I may serratipes, A-punctatum ct gutta- 

add, the male is testaceous and the turn ; see Westring, in Kroyer, 

female black with legs banded with ' Naturhist. Tidslcrift,' vol. iv. 1842- 

red. Other even more striking 1843, p. 349; and vol. ii. 1846-- 

cases of inequality in size between 1849, p. 342. See, also, for other 

the sexes have been recorded species, 'Aranege Suecica?,' p. 184. 

(' Quarterly Journal of Science,' ^^ Dr. H. H. van Zouteveen, in 

1868, July, p. 429) ; but I have his Dutch translation of this work 

not seen the original accounts. (vol. i. p. 444), has collected several 

2^ Kirby and Speuce, ' Introduc- cases 


2/4 The Descent of Man. Part II. 

to be described in the next chapter, we may feel almost sure that 
the stridulation serves, as Westring also believes, to call or to 
excite the female ; and this is the first case known to me in the 
ascending scale of the animal kingdom of sounds emitted for 
this purpose.^" 

Class, Myriaj;oda. — In neither of the two orders in this class, 
the millipedes and centipedes, can I find any well-marked 
instances of such sexual differences as more particularly concern 
us. In Glomeris li.mhata, however, and perhaps in some few 
other species, the males differ slightly in colour from the females ; 
but this Glomeris is a highly variable species. In the males of 
the Diplopoda, the legs belonging either to one of the anterior or 
of the posterior segments of the body are modified into pre- 
hensile hooks which serve to secure the female. In some species 
of lulus the tarsi of the male are furnished with membranous 
suckers for the same purpose. As we shall see when we treat 
of Insects, it is a much more unusual circumstance, that it is 
the female in Lithobius, which is furnished with prehensile 
appendages at the extremity of her body for holding the male.^^ 

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 understood — 
Difference in size between the sexes — Thysanura — Diptera — Hemiptera 
— Homoptera, musical powers possessed by the males alone — Orthoptera, 
musical instruments of the males, much diversified in structure ; 
pugnacity ; colours — Neuroptera, sexual differences in colour — Hyme- 
noptera, pugnacity and colours — Coleoptera, colours ; furnished with 
great horns, apparently as an ornament ; battles ; stridulating organs 
generally common to both sexes. 

In the immense class of insects the sexes sometimes differ in 
their locomotive-organs, and often in their sense-organs, as in 
the pectinated and beautifully plumose antennae of the males of 
many species. In Chloeon, one of the EjDhemerse, the male has 
great pillared eyes, of which the female is entirely destitute.* 
The ocelli are absent in the females of certain insects, as in the 

2^ Hilgendorf, however, has lately ' Hist. Nat. des Insectes : Apteres,' 

called attention to an analogous torn. iv. 1847, pp. 17, 19, (58. 
structure in some of the higher * Sir J. Lubbock, ' Transact, 

crustaceans, which seems adapted Linnean Soc' vol. xxv. 1866, p. 

to produce sound ; see ' Zoological 484. With respect to the Mu- 

Record,' 1869, p. 603. tillidae see West wood, ' Modern 

^^ Walckenaer et P. Gervais, Class, of Insects,' vol. ii. p. 213. 

Chap. X. Insects. 275 

Mutillidie ; and here the females are hkewise 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 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 some- 
times used for this purpose; thus the male Corydalis cornutus (a 
neuropierous insect in some degree allied to the Dragon-flies, &c.) 
lias immense curved jaws, many times longer than those of the 
female ; and they are smooth instead of being toothed, so that 
he is thus enabled to seize her without injury.'^ One of the 
stag-beetles of North America {Lucanus ela/Juis) uses his jaws, 
which are much larger than those of the female, for the same 
purpose, but probably likewise for fighting. In one of the 
sand-wasps {Ammophild) the jaws in the two sexes are closely 
alike, but are used for widely different purposes : the males, as 
Professor Westwood observes, " are exceedingly ardent, seizing 
" their partners round the neck with their sickle-shaped jaws;"^ 
whilst the females use these organs for burrowing in sand-banks 
and making their nests. 

The tarsi of the front-legs are dilated in many male beetles, or 
are furnished with broad cushions of hairs ; and in many genera 
of water-beetles they are armed with a round flat sucker, so that 
the male may adhere to the slippery body of the female. It is a 

"^ These organs in the male often species having been observed in 

differ in closely-allied species, and union. Mr. MacLachlan informs 

afford excellent specific characters. me (vide ' Stett. Eut. Zeitung,' 

But their importance, from a func- 1867, s, 155) that when several 

tional point of view, as Mr. R. species of Phryganidje, which ])re- 

MacLachlan has remarked to me, sent strongly-pronounced differences 

has probably been overrated. It of this kind, were confined together 

has been suggested, that slight dif- by Dr. Aug. Meyer, theji coupled, 

ferences in these organs would and one pair produced fertile ova. 

suffice to prevent the intercrossing ^ t -pj^g Practical Entomologist,' 

_ of well-marked varieties or incipient Philadelphia, vol. ii. May, 1807, 

species, and would thus aid in their p. 88. 

development. That this can hardly '' Mr. Walsh, ibid. p. 107. 
be the case, we may infer from the ^ ' Modern classification of In- 
many recorded cases (see, for in- sects,' vol. ii. 1840, pp. 205, 206. 
instance, Bronn, ' Geschichte der Mr. Walsh, who called my attention 
Natur,' B. ii. 18-13, s. 164; and to the double use of the jaws, says 
Westwood, ' Transact. Ent. Soc' that he has repeatedly observed 
vol. iii. 1842, p. 195) of distinct this fact. 


The Descent of Man. 

Part II. 

much more unusual circumstance that the female of some water- 
beetles (Dytiscus) have their elytra deeply grooved, and in 
Acilius sulcatus thickly set with hairs, as an aid to the male. 

The females of some other water- 
beetles (Hydroporus) have their 
elytra punctured for the same 
purpose." In the male of Crahro 
cribrurius (fig. 9), it is the tibia 
which is dilated into a broad 
horny plate, with minute mem- 
braneous dots, giving to it a sin- 
gular appearance like that of a 
riddle.'' In the male of Penthe 
(a genus of beetles) a few of the 
middle joints of the antennae are 
dilated and furnished on the in- 
ferior surface with cushions of hair, 
exactly like those on the tarsi of 
the Carabidse, " and obviously for 
" the same end." In male dragon- 
flies, " the appendages at the tip 
" of the tail are modified in an 
" almost infinite variety of curious 
" patterns to enable them to em- 
^''- 'm^ai:!TowS^Sgure,fYEL"'"^ " brace the neck of the female." 

Lastly, in the males of many in- 
sects, the legs are furnished with peculiar spines, knobs or 
spurs ; or the whole leg is bowed or thickened, but this is by no 
means invariably a sexual character ; or one pair, or all three 
IDairs are elongated, sometimes to an extravagant length.^ 

The sexes of many species in all the orders present differences, 
of which the meaning is not understood. One curious case is 
that of a beetle (fig. 10), the male of which has the left mandible 
much enlarged; so that the mouth is greatly distorted. In 
another Carabidous beetle, Eurygnathus,^ we have the case. 

^ We have here a curious and 
inexplicable case of dimorphism, for 
some of the females of four Euro- 
pean species of Dytiscus, and of 
cei'tain species of Hydroporus, have 
their elytra smooth ; and no inter- 
mediate gradations between the 
sulcated or punctured, and the quite 
smooth elytra have been observed. 
See Dr. 11. Schaum, as quoted in 
the 'Zoologist,' vol. A-.-vi. 1847-48, 
p. 1896. Also Kirby and Spence, 

' Introduction to Entomology,' vol. 
iii. 1826, p. 305. 

^ Westwood, ' Modern Class.' vol. 
ii. p. 193. The following state- 
ment about Penthe, and others in 
inverted commas, are taken from 
Mr. Walsh, ' Practical Entomolo- 
gist,' Philadelphia, vol. ii. p. 88. 

^ Kirby and Spence, 'Introduct.' 
&c., vol. iii. pp. 332-336. 

^ ' Insecta Madcrensia,' 1854, p. 

Chap. X. 



unique as ftir as known to Mr. Wollaston, of the head of the 
female being much broader and larger, though in a variable 
degree, than that of the male. Any number 
of such cases could be given. They abound 
in the Lepidoptera: one of the most extra- 
ordinary is that certain male butterflies 
have their fore-legs more or less atrojiliied, 
with the tibise and tarsi reduced to mere ru- 
dimentary knobs. The wings, also, in the two 
sexes often differ in neuration,^*' and some- 
times considerably in outline, as in the Ari- 
coris epitiis, wiiicli was shewn to me in the 
British Museum by Mr. A. Butler. The males 
of certain South American butterflies have 
tufts of hair on the margins of the wings, 
and horny excrescences on the discs of the 
posterior pair.^^ In several British butter- 
flies, as shewn by Mr. Wonfor, the males alone 
are in parts clothed with peculiar scales. 

The use of the bright light 'of the female 
glow-worm has been subject to much discus- 
sion. The male is feebly luminous, as are the 
larva3 and even the eggs. It has been sup- 
posed by some authors that the light serves to 
frighten away enemies,- and by others to 
guide the male to the female. At last, Mr. 
Belt ^2 appears to have solved the difficulty : 
he finds that all the Lampyridse which he has 
tried are highly distasteful to insectivorous 
mammals and birds. Hence it is in accordance 
with Mr. Bates'" view, hereafter to be explained, 
that many insects mimic the Lampyridae 
closely, in order to be mistaken for them, and 
thus to escape destruction. He further be- 
lieves that the luminous species profit by 
being at once recognised as unpalatable. 
It is i^robable that the same explanation may be extended to the 

'^^ E. Doubleday, ' Annals and 74. Mr. Wonfor's observations are 
Mag. of Xat. Hist.' vol. i. 1848, p. quoted in ' Popular Science Review,* 
379. I may add that the wings in 1868, p. 343. 

^- 'The Naturalist in Nicaragua,' 
1874, pp. 316-320. On the phos- 
phorescence of the eggs, see 'Annals 
and Mag. of Nat. Hist.' 1871,' Nov., 
p. 372. 

Fig. 10. Taphroderes 
distortus (much en- 
larged). Upper fig- 
ure, male ; lower 
figure, female. 

certain Hymenoptera (see Shuclvard, 
' Fossorial Hynienop.' 1837, pp. 39- 
43) differ in neuration according to 

" H. W. Bates, in 'Journal of 
Proc. Linn. Soc' vol. vi. 1862, p. 

2/8 The Descent of Man, Part 11. 

Elaters, both sexes of which are highly luminous. It is not 
known why the wings of the female glow-worm have not been 
developed ; but in her present state she closely resembles a 
larva, and as larvae are so largely preyed on by many animals, 
we can understand why she has been rendered so much more 
luminous and conspicuous than the male ; and why the larvae 
themselves are likewise luminous. 

Difference in Size hetween the Sexes. — "With insects of all kinds 
the males are commonly smaller than the females; and this 
difference can often be detected even in the larval state. So 
considerable is the difference between the male and female 
cocoons of the silk-moth (Bomhyx mori), that in France they are 
separated by a particular mode of weighing.^^ In the lower 
classes of the animal kingdom, the greater size of the females 
seems generally to depend on their developing an enormous 
number of ova ; and this may to a certain extent hold good with 
insects. But Dr. Wallace has suggested a much more probable 
explanation. He finds, after carefully attending to the develop- 
ment of the caterpillars of Bombyx cynthia and yamamai, and 
especially to that of some dwarfed caterjDillars reared from a 
second brood on unnatural food, " that in proportion as the in- 
" dividual moth is finer, so is the time required for its metamor- 
" pilosis longer ; and for this reason the female, which is the 
" larger and heavier insect, from having to carry her numerous 
" eggs, will be preceded by the male, which is smaller and has 
" less to mature," ^^ Now as most insects are short-lived, and as 
they are exposed to many dangers, it would manifestly be ad- 
vantageous to the female to be impregnated as soon as possible. 
This end would be gained by the males being first matured in 
large numbers ready for the advent of the females ; and this 
again would naturally follow, as Mr A. E. "Wallace has re- 
marked,^^ through natural selection; for the smaller males 
would be first matured, and thus would procreate a large 
number of offspring which would inherit the reduced size of 
then* male parents, whilst 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 jDossession of the females ; and in 
those cases, as with the stag-beetle (Lucanus), the males are 
larger than the females. There are, however, other beetles 

" Robinet, 'Vers a Soie,' 1848, vol. y. p. 486. 
p. 207. '5 i Journal of Proc. Ent. Soc. 

^^ 'Transact. Ent. Soc' 3rd series, Feb. 4th, 1867, p. Ixxi. 

Chap. X. TJiysanura. 279 

which are not known to fight together, of which the males 
exceed the females in size ; and the meaning of this fact is not 
known ; but in some of these cases, as with the huge Dynastes 
and Megasoma, we can at least see that there would be no 
necessity for the males to be smaller than the females, in order 
to be matured before them, for these beetles are not short-lived, 
and there would be ample time for the pairing of the sexes. So 
again, male dragon-flies (Libellulidse) are sometimes sensibly 
larger, and never smaller, than the females;^*' and as Mr. 
MacLachlan believes, they do not generally pair with the females 
until a week or fortnight has elapsed, and until they have 
assumed their proper masculine colours. But the most curious 
case, shewing on what comj^lex and easily-overlooked relatioDS, 
so trifling a character as difference in size between the sexes 
may depend, is that of the aculeate Hymenoptera ; for Mr. F. 
Smith informs me that throughout nearly the whole of this 
large group, the males, in accordance with the general rule, are 
smaller than the females, and emerge about a week before them ; 
but amongst the Bees, the males oi Aipis melUfica, Anthidium 
manicatum, and Anthopliora ac&rvorum, and amongst the Fossores, 
the males of the Methoca ichneumonides, are larger than the 
females. The explanation of this anomaly is that a marriage 
flight is absolutely necessary with these species, and the male 
requires great strength and size in order to carry the female 
through the air. Increased size has here been acquired in op- 
position to the usual relation between size and the period of 
development, for the males, though larger, emerge before the 
smaller females. 

We will now review the several Orders, selecting such facts 
as more particularly concern us. The Lepidoptera (Butterflies 
and Moths) will be retained for a separate chapter. 

Order, Thysanura. — The members of this lowly organized 
order are wingless, dull-coloured, minute insects, with ugly, 
almost misshapen heads and bodies. Their sexes do not difi"er ; 
but they are interesting as shewing us that the males pay 
sedulous court to the females even low down in the animal 
scale. Sir J. Lubbock ^^ says : " it is very amusing to see these 
" little creatures (SmyntJmrus 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 

'® For this and other statements see p. 344, 
on the size of the sexes, see Kirby ^' ' Transact. Linnean Soc' vol. 

and Spence, ibid. vol. iii. p. 300 ; xxvi, 1868, p. 296. 
on the dui'ation of life in insects, 

28o The Descent of Man. Part II. 

" backward and forward like tw'o 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 antennae ; then for a bit they stand face to face, 
" play with their antennae, and seem to be all in all to one 
" another." 

Order, Dlptera (Flies). — The sexes differ little in colour. The 
greatest difference, known to Mr. F. Walker, is in the genus 
Bibio, in which the males are blackish or quite black, and the 
females obscure brownish-orange. The genus Elaphomyia, dis- 
covered by Mr. Wallace ^^ in New Guinea, is highly remarkable, 
as the males are furnished with horns, of which the females are 
quite destitute. The horns spring from beneath the eyes, and 
curiously resemble those of a stag, being either branched or pal- 
mated. In one of the species, they equal the whole body in 
length. They might be thought to be adapted for fighting, but 
as in one species they are of a beautiful pink colour, edged with 
black, with a pale central stripe, and as these insects have 
altogether a very elegant appearance, it is perhaps more probable 
that they serve as ornaments. That the males of some Diptera 
fight together is certain ; for Prof. Westw^ood ^^ has several times 
seen this with the Tipulse. The males of other Diptera ap- 
parently try to win the females by their music : H. Miiller ^ 
watched for some time two males of an Eristalis courting a 
female; they hovered above her, and flew from side to side, 
making a high humming noise at the same time. Gnats and 
mosquitoes (Culicidse; also seem to attract each other by hum- 
ming ; and Prof. Mayer has recently ascertained that the hairs 
on the antennae of the male vibrate in unison with the notes of a 
tuning-fork, within the range of the sounds emitted by the female. 
The longer hairs vibrate sympathetically with the graver notes, 
and the shorter hairs with the higher ones. Landois also asserts 
that he has repeatedly drawn down a whole swarm of gnats by 
uttering a particular note. It may be added that the mental 
faculties of the Diptera are probably higher than in most other in- 
sects, in accordance with their highly developed nervous system.^^ 

^* * The Malay Archipelago,' vol. ^i ggg ^ly^ -^ f. Lowne's interest- 

ii. 1869, p. 313. ing work, ' On the Anatomy of the 

'^ 'Modern Classification of In- Blow-fly, Musca vomitoria,' 1870, p. 

sects,' A'ol. ii. 1840, p. 526. 14. He remarks (p. 33) that, " the 

2" Anwendung, &c., ' Verh. d. n. " captured flies utter a peculiar 

V. Jahrg.' xxix. p. 80. Mayer, in " plaintive note, and that this sound 

'American Naturalist,' 1874, p. 236. " causes other flies to disappear." 

Chap. X. Hemiptera and Homoptera, 281 

Order, Hemiptera (Field-Bugs).— Mr. J. W. Douglas, who has 
particularly attended to the British species, has kindly given me 
an account of their sexual differences. The males of some species 
are furnished with wings, whilst the females are wingless ; the 
sexes differ in the form of their bodies, elytra, antenn£e and tarsi ; 
but as the signification of these differences are unknown, they 
may be here passed over. The females are generally larger and 
more robust than the males. With British, and, as far as 
Mr. Douglas knows, with exotic species, the sexes do not 
commonly differ much in colour; but in about six British 
species the male is considerably darker than the female, and 
in about four other species the female is darker than the male. 
Both sexes of some species are beautifully coloured; and as 
these insects emit an extremely nauseous odour, their con- 
spicuous colours may serve as a signal that they are unpalat- 
able to insectivorous animals. In some few cases their colours 
appear to be directly protective : thus Prof. Hoffmann informs 
me that he could hardly distinguish a small pink and green 
species from the buds on the trunks of lime-trees, which this 
insect frequents. 

Some species of Eeduvidae 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. Accord- 
ing to Westring, Beduvius jiersonatus also stridulates. But I 
have no reason to suppose that this is a sexual character, ex- 
cepting that with non-social insects there seems to be no use 
for sound-producing organs, unless it be as a sexual call. 

Order, Homoptera. — Every one who has wandered in a tropi- 
cal forest must have been astonished at the din made by the 
male Cicadae. The females are mute; as the Grecian poet 
Xenarchus says, " Happy the Cicadas live, since they all have 
*' voiceless waives." The noise thus made could be plainly heard 
on board the " Beagle," when anchored at a quarter of a mile 
from the shore of Brazil ;• and Captain Hancock says it can be 
heard at the distance of a mile. The Greeks formerly kept, and 
the Chinese now keep these insects in cages for the sake of 
their song, so that it must be pleasing to the ears of some men.^^ 
The Cicadidse usually sing during the day, whilst the FulgoridsB 
appear to be night-songsters. The sound, according to Landois,^* 

" Westwood, 'Modern Class, of also, on the Fulgorida?, Kirby and 

Insects,' vol. ii. p. 473. Spence, ' Introduct.' vol. ii. p. 401. 

"^ These particulars are taken ^4 < Zeitschrift fiir wissenschaft. 

from Westwood's ' Modern Class, of Zoolog.' B. xvii. 1867, s. 152-158. 
Insects,' vol. ii. 1840, p. 422. See, 

282 The Descent of Man. Part II. 

is produced by the vibration ot the lips of the spiracles, which 
are set into motion by a current of air emitted from the trachese ; 
but tills view has lately been disputed. Dr. Powell appears to 
have proved 2^ that it is produced by the vibration of a mem- 
brane, set into action by a speci-al muscle. In the living insect, 
whilst stridulating, this membrane can be seen to vibrate ; and 
in the dead insect the proper sound is heard, if the muscle, 
when a little dried and hardened, is pulled with the point of a 
pin. In the fem.ale 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, ^s 
" the drums are now (June 6th and 7th, 1851) heard in all 
" directions. This I believe to be the marital summons from 
" the males. Standing in thick chestnut sprouts about as high 
" as my head, where hundreds were around me, I observed the 
" females coming around the drumming males," Ho adds, " this 
" season (Aug. 1868) a dwarf pear-tree in my garden produced 
" about fifty larvsB of Cic. prm7iosa ; and I several times noticed 
" the females to alight near a male while he was uttering his 
" clanging notes." Fritz Miiller writes to me from S. Brazil 
that he has often listened to a musical contest between two or 
three males of a species with a particularly loud voice, seated 
at a considerable distance from each other : as soon as one had 
finished his song, another immediately began, and then another. 
As there is so much rivalry between the males, it is probable 
that the females not only find them by their sounds, but that, 
like female birds, they are excited or allured by the male with 
the most attractive voice. 

I have not heard of any well-marked cases of ornamental 
differences between the sexes of the Homoptera. Mr. Douglas 
informs me that there are three British species, in which the 
male is black or marked with black bands, whilst the females are 
pale-coloured or obscure. 

Order, Orthoptera (Crickets and Grasshoppers).— The males in 
the three saltatorial families in this Order are remarkable for 
their musical powers, namely the Achetidse or crickets, the 
Locustidse for which there is no equivalent English name, and the 
Acridiidae or grasshoppers. The stridulation produced by some 

" 'Transact. New Zealand In- from a 'Journal of the Doings of 

stitute,' vol. V. 1873, p. 286. Cicada septemdecim ' by Dr. Hart- 

2^ I am indebted to Mr. Walsh man. 
for havmg sent me this extract 

Chap. X. 



of the Locustidse is so loud that it can be heard during tlie 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 tliat 
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 a male. The males 
of this species {Pachytylus miyratorius) whilst coupled with the 
female stridulate from anger or jealousy, if approached by other 
males. The house-cricket when surprised at night uses its voice 
to warn its fellows.-^ In North America the Katy-did {Phity- 
2>hyllum coneavum,onQoii\\Q Locustidse) is described^" as mount- 
ing on the upper branches of a tree, and in the evening beginning 
" his noisy babble, while rival notes issue from the neighbouring 
" trees, and the groves resound with the call of Kafydid-she-did 
" the hve-long night." Mr. 
Bates, in speaking of the Euro- 
pean field-cricket (one of the 
Achetidse), says, " the male has 
" been observed to jDlace him- 
" self in the evening at the 
" entrance of his burrow, and 
" stridulate until a female ap- 
" preaches, when the louder 
" notes are succeeded by a 
" more subdued tone, whilst 
" the successful musician ca- 
" resses with his antennae the 
" mate he has won."^^ 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 re- 
markable auditory apparatus 
has been discovered by Von Siebold, situated in the front legs 

Fig. 11, Gryllus carapestris (from Landois). 
Right-hand figure, under side of part of a 

wing-nervure, much magnified, showing 

the teeth, st. 
Left-hand figure, upper surface of wing- 

cover, with the projecting, smooth nervure, 

r, across which the teeth {st) are scraped. 

2^ L. Guilding, 'Transact Linn. 
See' vol. XV. p. 154. 

28 I state this on the authority 
of Koppen, ' Ueber die Heuschrecken 
in Siidrussland,' 1866, p. 32, for I 
have in vain endeavoured to procure 
Korte's work. 

29 Gilbert White, 'Nat. Hist, of 
Selborne,' vol. ii. 1825, p. 262. 

^" Harris, ' Insects of New Eng- 
land/ 1842, p. 128. 

31 'The Naturalist on the Ama- 

zons,' vol. i. 1863, p. 252. Mr. 
Bates gives a very interesting dis- 
cussion on the gfadations in the 
musical apparatus of the three 
families. See also Westwood, 
* Modern Class.' vol. ii. pp. 445 
and 453. 

32 'Proc. Boston Soc. of Nat. 
Hist.' vol. xi. April, 1868. 

33 ' Nouveau Manuel d'Anat. 
Comp.' (French translat.), torn. i. 
1850, p. 567. 

284 The Descent of Man. Part II. 

In the three ramilies the sounds are differently produced. In 
the males of the Achetidse both wing-covers have the same 
apparatus ; and this in the field-cricket {Gryllus campestris, 
fig. 11) consists, as described by Landois,^* of from 131 to 138 
sharp, transverse ridges or teeth (.s^) on the under side of one of 
the nervures of the wing-cover. This toothed nervure is rapidly 
scraped across a projecting, smooth, hard ner- 
vure (r) on the upper surface of the opposite 
wing. First one wing is rubbed over the 
other, and then the movement is reversed. 
Both wings are raised a little at the same 
time, so as to increase the resonance. In 
some species the wing-covers of the males are 
furnished at the base with a talc-like plate.^^ 
I here give a drawing (fig. Vl) of the teeth on 
the under side of the nervure of another 
Fig. 12. Teeth of Ner- spccics of Grvllus, viz., (J. domesticus. With 
SrcS^SoS)!' 'respect to the formation of these teeth. Dr. 
Gruber has shewn ^*^ that they have been de- 
veloped by the aid of selection, from the minute scales and hairs 
with which the wings and body are covered, and I came to the 
same conclusion with respect to those of the Coleoptera. But 
Dr. Gruber further shews that their development is in part 
directly due to the stimulus from the friction of one wing over 
the other. 

In the Locustidse the opposite wing-covers differ from each 
other in structure (fig. 13), and the action caonot, as in the 
last family, be reversed. The left wing, which acts as the 
bow, lies over the right wing which serves as the fiddle. One 
of the nervures (a) on the under surface of the former is 
finely serrated, and is scraped across the prominent nervures 
on tlie upper surface of the opposite or right wing. In our 
British fhasgonura viridissima it appeared to me that the 
serrated nervure is rubbed against the rounded hind-corner 
of the opposite wing, the edge of which is thickened, coloured 
brown, and very sharp. In the right wing, but not in the left, 
there is a little plate, as transparent as talc, surrounded by 
nervures, and called the speculum. In Epliiiiinger 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 

^* ' Zeitschi-ift fiir wissenschaft. ^^ ' Ueber der Tonapparat der 

Zoolocf.' B. xvii. 1867, s. 117. Locustiden, ein Beitrag zum Dar- 

^^ Westwood, ' Modern Class, of wiaismus,' ' Zeitsch. fiir wissensch. 

Insects,' vol. i. p. 440. Zoolog.' B. xxii. 1872, p. 100. 

Chap. X. 



"of dome over tlie wing-covers, and which hxis probably the 
" effect of increasing the sound." '^'^ 

Fig. 13. ChloroccElus Tanana (from Bates), a, b. Lobes ux" opposite wing-covers. 

We thus see that the musical apparatus is more differentiated 
or specialised in the Locustidse (which include, I believe, the 
most powerful performers in the Order), than in the Achetidre, 
in which both wing-covers have the same structure and the 
same function.'^ Landois, however, detected in one of the 
Locustidae, 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 tlje bow. 
I observed the same rudimentary structure on the under side of 
the right wing-cover in Phasyonura viridissima. Hence we may 
infer with confidence that the Ijocustidsa are descended from a 
form, in which, as in the existing Achetidse, both wing-covers 
had serrated nervures on the under surface, and could be 
indifferently used as the bow ; but tliat in the Locustidse the 
two wing-covers gradually became differentiated and perfected. 

2' Westwood, 'Modern Class, of Insects,' vol. i. p. 453. 

^^ Landois, 'Zeitsch. f. wiss. Zoolog.' B. xvii. 1867, s. 121, 122. 


The Descent of Man, 

Part II. 

on the principle of the division of labour, the one to act ex- 
clusively as the bow, and the other as the fiddle. Dr. Gruber 
takes the same view, and has shewn that rudimentary teeth are 
commonly found on the inferior surface of the right wing. By 
what steps the more simple apparatus in the Achetidse originated, 
we do not know, but it is probable that the basal portions of 
the wing-covers originally overlapped each other as they do at 
present; and that the friction of the nervures produced a 
gTating sound, as is now the case with the wing-covers of tlie 
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 Acridiidse or 
grasshoppers, the stridulation is produced in a very different 
manner, and according to Dr. Scudder, is not so shrill as in the 
prec.eding Families. The inner surface of the femur (fig. 14, r) 
is furnished with a longitudinal row of minute, elegant, lancet- 
shaped, elastic teeth, from 85 to 93 in number ;^*' and these are 
scraped across the sharp, projecting nervures on the wing-covers, 
which are thus made to vibrate and resound. Karris'*^ 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 alternately, first upon 
" one and then on the other." 
In many species, the base 
of the abdomen is hollowed 
out into a great cavity which 
is believed to act as a re- 
sounding board. In Pneu- 
mora (fig. 15), a S. African 
same family, we meet with a new 

Fig. 14. Hind-leg of Stenobothrus pratorum : 
r, the stridulating ridge ; lower figure, the 
teeth forming the ridge, much magnified 
(from Landois). 

genus belonging to the 

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." 

*" Landois, ibid. s. 113. 

*i ' Insects of New England, 
1842, p. 133. 

Chap. X. 



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 re- 
markable that the thighs are not rubbed in tlie usual manner 
against the "wing-covers ; but this may perhaps be accounted for 
by the unusually small size of the hind-legs. I have not been 
able to examine the inner surface of the thighs, which, judging 

Fig. 15. Pneumora (from specimens in the British Museum). Upper figure, male; 
lower figure, female. 

from analogy, would be finely serrated. The species of Pneumora 
have been more profoundly modified for the sake of stridulation 
than any other orthopterous insect ; for in the male the whole 
body has been converted into a musical instrument, being 

*• Westwood, ' Mode] u Classification,' vol. i. p. 462. 

288 The Descent of Man. Part II. 

distended witli air, like a great pellucid bladder, so as to 
increase the resonance. Mr. Trimen informs me that at the 
Cape of Good Hope these insects make a wonderful noise 
during the night. 

In the three foregoing families, the females are almost always 
destitute of an efficient musical apparatus. But there are a few 
exceptions to this rule, for Dr. Gruber has shewn that both 
sexes of Eplujypiger vitium are thus provided; though the organs 
differ in the male and female to a certain extent. Hence we 
cannot suppose that they have been transferred from the male 
to the female, as appears to have been the case with the secondary 
sexual characters of many other animals. They must have been 
independently developed in the two sexes, which no doubt 
mutually call to each other during the season of love. In most 
other Locustidse (but not according to Landois in Decticus) the 
females have rudiments of the stridulatory organs proper to the 
male; from whom it is probable that these have been transferred. 
Landois also found such rudiments on the under surface of the 
wing-covers of the female Achetidse, and on the femora of the 
female Acridiidte. In the Homoptera, also, the females have the 
proper musical apparatus in a functionless state ; and we shall 
hereafter meet in other divisions of the animal kingdom with 
many instances of structures proper to the male being present 
in a rudimentary condition in the female. 

Landois has observed another important fact, namely, that in 
the females of the Acridiidte, the stridulating teeth on the 
femora remain throughout life in the same condition in which 
they first appear during the larval state in both sexes. In the 
males, on the other hand, they become further developed, and 
acquire their perfect structure at the last moult, when the insect 
is mature and ready to breed. 

From the facts now given, we see that the means by which 
the males of the Orthoptera produce their sounds are extremely 
diversified, and are altogether different from those employed by 
the Homoptera.^^ But throughout the animal kingdom we 
often find the same object gained by the most diversified means ; 
this seems due to the whole organisation having undergone mul- 
tifarious changes in the course of ages, and as part after part 
varied different variations were taken advantage of for the 
same general purpose. The diversity of means for producing 
sound in the three families of the Orthoj^tera and in the 

*^ Landois has recently found in moptera ; and this is a surprising 

certain Orthoptera rudimentary fact. See ' Zeitschr. fiir wissensch. 

structures closely similar to the Zoolog.' B. xxii. Heft 3, 1871, p. 

sound-producing organs in the Ho- 348. 

Chap. X.- Or t hop t era. 289 

Bomoptera, 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 stridu- 
" lating apparatus of the male Locustidse." The insect, though 
in most respects related to the Neuroptera, appears, as is so often 
the case with very ancient forms, to connect the two related 
Orders of the Neuroptera and Orthoptera. 

I have but little more to say on the Orthoptera. Some of the 
species are very pugnacious: when two male field-crickets 
(GryUus camjoestris) are confined together, they fight till one 
kills the other; and the species of Mantis are described as 
mancBuvriug 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 
colour, some exotic locusts are beautifully ornamented ; the 
posterior wings being marked with red, blue, and black ; but as 
throughout the Order the sexes rarely differ much in colour, it 
is not probable that they owe their bright tints to sexual 
selection. Conspicuous colours may be of nse to these insects, 
by giving notice that they are unpalatable. Thus it has been 
observed ^° that a bright-coloured Indian locust was invariably 
rejected when offered to birds and lizards. Some cases, however, 
are known of sexual differences in colour in this Order. The 
male of an American cricket-*^ is described as being as white as 
ivory, whilst the female varies from almost white to greenish- 
yellow or dusky. Mr. Walsh informs me that the adult male of 
Spectrum femoratum (one of the Phasmidse) " is of a shining 
" brownish-yellow colour ; the adult female being of a dull, 
" opaque, cinereous brown ; the young of both sexes being green." 
Lastly, I may mention that the male of one curious kind of 
cricket*^ is furnished with "a long membranous appendage, 
" which falls over the face like a veil ;" but what its use may be, 
is not known. 

** ' Transact. Ent. Soc' 3r J series, *^ The CEcantlms nivalis. Harris, 

vol. ii. ('Journal of Proceedings,' 'Insects of New England,' 1842, p.. 

p. 117.) " 124. The two sexes of (E. pcllucichts ' 

*^ Westwood, ' Modern Class, of of Europe differ, as I hear from 

Insects,' vol. i. p. 427 ; for crickets, Victor Carus, in nearly the same 

p. 445. manner. 

*^ Mr. Ch. Home, in ' Proc. Ent. ** Platyblemnus : Westwood, 

Soc ' May 3, 1869, p. xii. ' Modern Class.' vol. i. p. 447. 

2QO The Descent of Man. Part II. 

Order, Neuroj)tera. — Little need here be said, except as to 
colour. In the Ephemeridse 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 Ijibellulidae, or 
dragon-flies, are ornamented with sjDlendid green, blue, yellow, 
and vermilion metallic tints ; and the sexes often differ. Thus. 
as Prof. Westwood remarks,^" the males of some of the 
Agrionidae, " are of a rich blue with black wings, whilst the 
'* females are fine green with colourless wings." But in Agrion 
Bamhurii these colours are exactly reversed in the two sexes.^^ 
In the extensive N. American genus of Hetserina, the males alone 
have a beautiful carmine spot at the base of each wing. In 
Anax Junius the basal part of the abdomen in the male is a vivid 
ultramarine blue, and in the female grass-green. In the allied 
genus Gomphus, on the other hand, and in some other genera, 
the sexes differ but little in colour. In closely-allied forms 
throughout the animal kingdom, similar cases of the sexes 
differing greatly, or very little, or not at all, are of frequent 
occurrence. Although there is so wide a difference in colour 
between the sexes of many Libellulidse, it is often difficult to say 
which is the more brilliant ; and the ordinary coloration of the 
two sexes is reversed, as we have just seen, in one species of 
Agrion. It is not probable that their colours in any case have 
been gained as a protection. Mr. MacLachlan, who has closely 
attended to this family, writes to me that dragon-flies— the 
•tyi-ants of the insect-world — are the least liable of any insect to 
be attacked by birds or other enemies, and he believes that their 
bright colours serve as a sexual attraction. Certain dragon-flies 
apparently are attracted by particular colours : Mr. Patterson 
observed ^^ that the Agrionidrs, of which the males are blue, 
settled in numbers on the blue float of a fishing line ; whilst two 
other species were attracted by shining white colours. 

It is an interesting fact, first noticed by Schelver, that, in 
several genem belonging to two sub-families, the males on first 
emergence from the pupal state, are coloured exactly like the 
females; but that their bodies in a short time assume a con- 
spicuous milky-blue tint, owing to the exudation of a kind of oil, 
soluble in ether and alcohol. Mr. MacLachlan believes that in 
the male of Lihelkda depressa this change of colour does not occur 
until nearly a fortnight after the metamorphosis, when the sexes 
are ready to pair. 

*^ B. D. Walsh, the ' Pseudo-neu- indebted to this naturalist for the 

roptera of Illinois,' in ' Proc. Ent. following facts on Hetarina, Anax, 

Soc. of Philadelphia,' 1862, p, 361. and Gomphus. 

5* 'Modern Class.' vol. ii. p. 37. ^- 'Transact. Ent. Soc' vol. i. 

" Walsh, ibid. p. 381. I am 1836, p. Ixxxi. 

CiiAP. X. HynieiiGptera. 291 

Certain si3ecies of Neurotliemis present, according to Brauer, °^ 
a curious case of dimorphism, some of the females having ordinary 
wings, whilst others have them " very richly netted, as in the 
" males of the same species." Brauer " exjilains the phenomenon 
" on Darwinian principles by the suj^position that the close 
" netting of the veins is a secondary sexual character in the 
" males, which has been abruptly transferred to some of the 
" females, instead of, as generally occurs, to all of them." Mr. 
MacLachlan informs me of another instance of dimorphism 
in several species of Agrion, in which some individuals are of 
an orange colour, and these are invariably females. This is 
probably a case of reversion ; for in the true Libellulse, when 
the sexes differ in colour, the females are orange or yellow; 
so that supposing Agrion to be descended from some primordial 
form which resembled the typical Libellulse in its sexual cha- 
racters, it would not be surprising that a tendency to vary in 
this manner should occur in the females alone. 

Although many dragon-flies are large, powerful, and fierce 
insects, the males have not been observed by Mr. MacLachlan to 
fight together, excepting, as he believes, in some of the smaller 
sj^ecies of Agrion. In another group in this Order, namely, the 
Termites or white ants, both sexes at the time of swarming may 
be seen running about, " the male after the female, sometimes 
" two chasing one female, and contending with great eagerness 
" who shall win the prize."^^ The Atropos pulsatorius is said 
to make a noise with its jaws, which is answered by other 

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 ^' says that the males of one of the saw-flies (Tenthre- 
dinse) " have been found fighting together, with their mandibles 
" locked." As M. Fabre speaks of the males of Cerceris striving 
to obtain a particular female, it may be well to bear in mind 
that insects belonging to this Order have the power of recognising 

^' See abstract in the ' Zoological ^^ See an interesting article. 

Record' for 1867, p. 450. 'The Writings of Fabre,' in 'Nat. 

^■* Kirby and Spence, 'Introduct. Hist. Review,' April 1862, p. 122. 
to Entomology,' vol. ii. 1818, p. 35. ^' 'Journal of Proc. of Entoraolog. 

" Houzeau, ' Les Facultes Men- Soc' Sept, 7th, 1863, p. 169. 
tales,' &c. Tom. 1. p. 104. 

292 The Descent of Man. Fart II. 

each other after long intervals of time, and are deeply attached. 
For instance, Pierre Hnber, whose accuracy no one doubts, 
separated some ants, and when, after an interval of four months, 
they met others which had formerly belonged to the same- 
community, they recognised and caressed one another with their 
antennae. Had they been strangers they would have fought 
together. Again, when two communities engage in a battle, the 
ants on the same side sometimes attack each other in tlie general 
confusion, but they soon perceive their mistake, and the one ant 
soothes tbe other.^^ 

In this Order slight differences in colour, 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 
coloured— for instance in Chrysis, in which vermilion and 
metallic greens prevail — that we are tempted to attribute the 
result to sexual selection. In the Ichneumonids^, according to 
Mr. Walsli,^^ the males are almost universally lighter-coloured 
than the females. On the other hand, in the Tenthredinidse the 
males are generally darker than the females. In the Siricidse 
the sexes frequently differ ; thus the male of Sirex juvencus is 
banded with orange, whilst the female is dark purple ; but it is 
difficult to say which sex is the more ornamented. In Tremex 
cohnnhop. the female is much brighter-coloured than the male. 
I am informed by Mr. F. Smith, that the male ants of several 
species are black, the females being testaceous. 

In the family of Bees, especially in the solitary species, as I 
hear from the same entomologist, the sexes often differ in colour. 
The males are generally the brighter, and in Bombus as well as in 
Apathus, much more variable in colour than the females. In 
Anthophora return the male is of a rich fulvous-brown, whilst 
the female is quite black : so are the females of several species 
of Xylocopa, the males being bright yellow. On the other hand 
the females of some species, as of Andrcena fiilva, are much 
brighter-coloured than the males. Such differences in colour' 
can hardly be accounted for by the males being defenceless and 
thus requiring protection, whilst the females are well defended 
by their stings. H. Miiller, *^° who has particularly attended to 
the habits of bees, attributes these differences in colour in chief 
part to sexual selection. That bees have a keen perception of 
colour is certain. He says that the males search eagerly and 
fight for the possession of the females ; and he accounts thi'ough 

58 p. Huber, ' Recherches sur les Philadelphia,' 1866, pp. 238-239. 

Moeurs des Fourmis,' 1810, pp. 150, ^^ ' Anwendung der Darwinschen 

165. Lehi-e auf Bienen.' Verh. d. li. 

^^ ' Proc. Entomolog. Soc. of Jahrg. xxix. 

Chap. X. Hyniienoptera. 293 

such contests for the mandibles of the males being in certain 
species larger than tliose of the females. In some cases tlie 
males are far more numerous than the females, either early 
in the season, or at all times and places, or locally ; whereas the 
females in other cases are apparently in excess. In some species 
the more beautiful males appear to have been selected by the 
females ; and in others the more beautiful females by the males. 
Consequently in certain genera (Miiller, p. 42), the males of the 
several species differ much in appearance, vs^hilst the females are 
almost indistinguishable; in other genera the reverse occurs. 
H. Miiller believes (p. 82) that the colours gained by one sex 
through sexual selection have often. been transferred in a variable 
degree to the other sex, just as the pollen-collecting apparatus 
of the female has often been transferred to the male, to whom 
it is absolutely useless.''^ 

Mutilla Earopxa makes a stridulating noise ; and according to 
Goureau ^'^ both sexes have this power. He attributes the sound 
to the friction of the third and preceding abdominal segments, 
and I find that these surfaces are marked with very fine con- 
centric ridges ; but so is the projecting thoracic collar, into which 
the head articulates, and this collar, when scratched with the 
point of a needle, emits the proper sound. It is rather surprising 
that both sexes should have the power of stridulating, as the 
male is winged and the female wingless. It is notorious that 
Bees express certain emotions, as of anger, by the tone of their 
humming; and according to H. Miiller (p. 80), the males of 
some species make a peculiar singing noise whilst pursuing the 

®^ M. Perrier in his article 'la Se- male grandfathers? To take a case 

lection sexuelled'aprfes Darwin '('Re- with ordinary animals as nearly 

vue Scientitiqiae,' Feb. 1873, p. 868), parallel as possible: if a female of 

without apparently having reflected any white quadruped or bird were 

much on the subject, objects that as crossed by a male of a black breed, 

the males of social bees are known and the male and female offspring 

to be produced from unfertilised were paired together, will it be 

ova, they could not transmit new pretended that the grandchildren 

characters to their male offspring. would not inherit a tendency to 

This is an extraordinary objection, blackness from their male grand- 

A female bee fertilised by a male, father? The acquirement of new 

which presented some character fa- characters by the sterile worker-bees 

cilitating the union of the sexes, or is a much more difficult case, but I 

rendering him more attractive to have endeavoured to show in my 

the female, would lay eggs which ' Origin of Species,' how these sterile 

would produce only females ; but beings are subjected to the power of 

these young females would next natural selection, 

year produce males ; and will it be ^^ Quoted by Westwood, ' Modern 

pretended that such males would- Class, of Insects,' vol. ii. p. 214-. 
not inherit the characters of their 

294 The Descent of Man. Part II. 

Order, Coleoj)tera (Beetles). — Many beetles are coloured so as 
to resemble the surfaces which they habitually frequent, and 
they thus escape detection by their enemies. Other species, for 
instance diamond-beetles, are ornamented with siDlendid colours, 
which are often arranged in stripes, spots, crosses, and other 
elegant patterns. Such colours can hardly serve directly as a 
protection, except in the case of certain flower-feeding species ; 
but they may serve as a warning or means of recognition, on the 
same principle as the phosphorescence of the glow-worm. As 
with beetles the colours of the two sexes are generally alike, we 
have no evidence that they have been gained through sexual 
selection; but this is at 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 
possess other well-marked secondary sexual characters. Blind 
beetles, which cannot of course behold each other's beauty, 
never, as I hear from Mr. Waterhouse, jun., exhibit bright 
colours, though they often have polished coats ; but the expla- 
nation of their obscurity may be that they generally inhabit 
caves and other obscure stations. 

Some Longicorns, especially certain Prionidse, offer an excep- 
tion to the rule that the sexes of beetles do not differ in colour. 
Most of these insects are large and splendidly coloured. The 
males in the genus Pyrodes,*^^ which I saw in Mr. Bates's col- 
lection, are generally redder but rather duller than the females, 
the latter being coloured of a more or less splendid golden-green. 
On the other hand, in one species the male is golden-green, the 
female being richly tinted with red and purple. In the genus 
Esmeralda the sexes differ so greatly in colour that they have 
been ranked as distinct species ; in one species both are of a 
beautiful shining green, but the male has a red thorax. On the 
whole, as far as I could judge, the females of those Prionidse, in 

"^ Pyrodes pulcherrimus, in the family of Longicorns. Messrs. 

which the sexes differ conspicuously, R. Trimen and Waterhouse, jun., 

has been described by Mr. Bates in inform me of two Lamellicorns, 

'Transact. Ent. Soc' 1869, p. 50. viz., a Peritrichia and Trichius, the 

I will specify the few other cases in male of the latter being more 

which 1 have heard of a difference obscurely coloured than the female. 

m colour between the sexes of In Tillus elongatus the male is black, 

beetles. Kirby and Spence (' In- and the female always, as it is 

troduct. to Entomology,' vol. iii. p. believed, of a dark blue colour, with 

301) mention a Cantharis, Meloc, a red thorax. The male, also, of 

Rhagium, and the Leptura testacca ; Orsodacna atra, as I hear from Mr. 

the male of the latter being tes- Walsh, is black, the female (the 

taceous, with a black thorax, and so-called 0. ruficollis) having .a 

the female of a dull red all over, rufous thorax. two latter beetles belong to 

Chap. X. 



which the sexes differ, are coloured more richly than the males, 
and 'this does not accord with the common rule in regard to 
colour, when acquired through sexual selection. 

A most remarkable distinction between the sexes of many 
beetles is presented by the great horns which rise from the head, 
thorax, and clypeus of the males ; and in some few cases from 
the under surface of the body. These horns, in the great family 
of the Lamellicorns, resemble those of various quadrupeds, such 
as stags, rhinoceroses, &c., an-d are wonderful both from their 
size and diversified shapes. Instead of describing them, I have 
given figures of the males and females of some of the more re- 
markable forms. (Figs. 16 to 20.) The females generally ex- 
liibit rudiments of the horns in the form of small knobs or 
ridges ; but some are destitute of even the slightest rudiment. 
On the other hand, the horns are nearly as well developed in the 
female as in the male of Phanceus lancifer ; and only a little less 
well developed in the females of some other species of this genus 
and of Copris. I am informed by Mr. Bates that the horns do 
not differ in any manner corresponding with the more important 
characteristic differences between the several subdivisions of the 
family : thus within the same section of the genus Onthophagus, 
there are species which have a single horn, and others which 
have two. 

Fig. 16. Chalcosoma atlas. Upper figure, male (roduced) ; lower figure, female 
(nat. size). 


'The Descent of Man. Part II. 

Copris isidis. (Left-hand figures, males.) 

Plianaeus faunus. 

Fisr. 19 

ripelicus cantoii. 

Fig. 20. Onthophagiis rangifer, enlarged 

Chap. X. ' Coleoptera. ' 297 

In almost all cases, the horns are remarkable from their ex- 
cessive variability; so that a graduated series can be formed, 
from the most highly developed males to others so degenerate 
that they can barely bo distinguished from the females. Mr. 
Walsh ^^ found that in Phcuueus caniifex the horns were thrice as 
long in some males as in others. Mr. Bates, after examining 
above a hundred males of Ontliophagus runcjifer (fig. 20), thought 
that he had at last discovered a species in which the horns did 
not vary ; but further research proved the contrary. 

The extraordinary size of the horns, and their widely different 
structure in closely-allied forms, indicate that they have been 
formed for some purpose ; but their excessive variability in the 
males of the same species leads to the inference that this purpose 
cannot be of a definite nature. The horns do not show marks of 
friction, as if used for any ordinary work. Some authors sup- 
pose "^^ that as the males wander about much more than the 
females, they require horns as a defence against tJieir enemies ; 
but as the horns are often blunt, they do not seem well adapted 
for defence. The most obvious conjecture is that they are used 
by the males for fighting together ; but the males have never 
been observed to fight; nor could Mr. Bates, after a careful 
examination of numerous species, find any sufficient evidence, in 
their mutilated or broken condition, of their having been thus 
used. If the males had been habitual fighters, the size of their 
bodies would probably have been increased through sexual 
selection, so as to have exceeded that of the females; but 
Mr. Bates, after comparing the two sexes in above a hundred 
species of the Copridse, did not find any marked difference in 
this respect amongst well-developed individuals. In Lethrus, 
moreover, a beetle belonging to the same great division of the 
Lamellicorns, the males are known to fi^'ht, but are not provided 
with horns, though their mandibles are much larger than those 
of the female. 

The conclusion that the horns have been acquired as ornaments 
is that which best agrees with the fact of their having been so 
immensely, yet not fixedly, developed, — as shewn by their extreme 
variability in the same species, and by their extreme diversity in 
closely- allied species. This view will at first appear extremely 
improbable; but we shall hereafter find with many animals 
standing much higher in the scale, namely fishes, amphibians, 
reptiles and birds, that various kinds of crests, knobs, horns and 
combs have been developed apparently for this sole purpose. 

The males of Onitls furciftr (fig. 21), and of some other 

^■* ' Pi-oc. Entomolog. Soc. of ^^ Kirby and Spence, ' latroduct. 

rhiladelphia,' 1864, p. 228. Entomolog.' vol. iii. p. 300. 



^he Descent of Man. 

Part II. 

species of tlie genus, are furnished with singular projections on 
their anterior femora, and with a great fork or pair of horns on 
the lower surface of the thorax. Judging 
from other insects, these may aid the male 
in clinging to the female. Although the 
males have not even a trace of a horn on 
the upper surface of the body, yet the fe- 
males plainly exhibit a rudiment of a single 
horn on the head (fig. 22, a), and of a crest 
(&) on the thorax. That the slight thoracic 
crest in the female is a rudiment of a pro- 
jection proper to the male, though entirely 
absent in the male of this jDarticular species, 
is clear : for the female of Buhas bison (a 
genus which comes next to Onitis) has a 
similar slight crest on the thorax, and the male bears a great 
projection in the same situation. So, again, there can hardly be 
a doubt that the little point (a) on the head of the female Onitis 

Fig 21. Onitis furcifer, 
male viewed from be- 

Fig. 22. Left-hand fignre, male of Onitis furcifer, viewed laterally. Right-hand 
figure, female, a. Rudiment of cephalic horn. b. Truce of thoracic horn or crest. 

furcifer, as well as on the head of the females of two or three 
allied species, is a rudimentary representative of the cephalic 
horn, which is common to the males of so many Lameilicorn 
beetles, as in Phanseus (fig. 18). 

The old belief that rudiments have been created to complete 
the scheme of nature is here so far from holding good, that we 
have a complete inversion of the ordinary state of things in the 
family. We may reasonably suspect that the males originally 
bore horns and transferred them to the females in a rudimentary 
condition, as in so many othej* Lamellicorns. Why the males 
subsequently lost their horns, we know not ; but this may have 
been caused through the principle of compensation, owing to 
the development of the large horns and projections on the lower 
surface ; and as these are confined to the males, the rudiments 
of the upper horns on the females would not have been thus 

Chap. X. Coleoptera, 299 

The cases hitherto given refer to the Lamellicorns, but the 
males of some few other beetles, belonging to two widely distinct 
groups, namely, the Cui'culionidre and Staphylinidce, are fur- 
nished with homs — in the former on the lower surface of the 
body,*"^ in the latter on the upi^er surface of the head and thorax. 
In the Staphylinid?e, 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 tiie size of their bodies and in the development of their 
horns, without intermediate gradations. In a species of Bledius 
(fig. 23), also belonging to the Staphylinidse, Professor Westwood 

Fig. 23. Bledius taurus, magnified. Left-hand figure, male ; right-hand figure female. 

states that, "male specimens can be found in the same locality 
" in which the central horn of the thorax is very large, but the 
" horns of the head quite rudimental ; and others, in which the 
"thoracic horn is much shorter, whilst the protuberances on 
" the head are long." *^^ Here we apparently have a case of 
compensation, which throws light on that just given of the 
supposed loss of the upper horns by the males of Onitis. 

Law of Battle. — Some male beetles, which seem ill-fitted .for 
fighting, nevertheless engage in conflicts for the possession of 
the females. Mr. Wallace *^^ saw two males of Leptorhynchus 
angustatus, a linear beetle with a much elongated rostrum, 
" fighting for a female, who stood close by busy at her boring. 
" They pushed at each other with their rostra, and clawed and 
" thumped, apparently in the greatest rage." The smaller male, 
however, " soon ran away, acknowledging himself vanquished." 
In some few cases male beetles are well adapted for fighting, by 
possessing great toothed mandibles, much larger than those of 
the females. This is the case with the common stag-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 

®® Kirby and Spence, ' Introduct. gonium in an intermediate condi- 

Entomolog.' vol. iii. p. 329. tion, .so that the dimorphism is not 

®^ ' Modern Classification of In- strict, 
sects,' vol. i. p. 172: Siagonium, ^^ 'The Malay Archijjelago,' vol. 

p. 172. In the British Museum I ii. 1869, p. 276. Riley, Sixth "* Report 

noticed one male specimen of Sia- on insects of Missouri/ 1874, p. 115. 

300 The Descent of Mmi. Part II. 

engage in fierce conflicts. When Mr. A. H. Davis *^^ enclosed 
two males with one female in a box, the larger male severely 
I.)inched the smaller one, until he resigned his pretensions. A 
friend informs me that when a boy he often iDut the males 
together to see them fight, and he noticed that they were much 
bolder and fiercer than the females, as with the higher animals. 
The males would seize hold of his finger, if held in front of 
them, but not so the females, although they have stronger 
jaws. The males of many of the Lucanidse, as well as of the 
above-mentioned Leptorhynchus, are larger and more powerful 
insects than the females. The two sexes of Lethnis cepJialotes 
(one of the Lamellicorns) inhabit the same burrow; and the 
male has larger mandibles than the female. If, during the 
breeding-season, a strange male attempts to enter the burrow, 
he is attacked ; the female does not remain passive, but closes 
the mouth of the burrow, and encourages her mate by con- 
tinually pushing him on from behind ; and the battle lasts until 
the aggressor is killed or runs away. '** The two sexes of another 
Lamellicorn beetle, the Ateuchus cicafricosus, 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 Lucanidse are extremely 
variable both in size and structure, and in this respect resemble 
the horns on the head and thorax of many male Lamellicorns 
and Staphylinidse. A perfect series can be formed from the 
best-provided to the worst-provided or degenerate males. Al- 
though the mandibles of the common stag-beetle, and probably 
of many other species, are used as 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 N. America for seizing the female. As they are so con- 
spicuous and so elegantly branched, and as owing to their great 
length they are not well adapted for pinching, the suspicion 
has crossed my mind that they may in addition serve as an 
ornament, like the horns on the head and thorax of the various 
species above described. The male Chiaf^ognathus Grant ii of 
S. Chile — a splendid beetle belonging to the same family — has 

^^ 'Entomological Magazine,' vol. ""^ Quoted from Fischer, in '•Diet, 

i. 1833, p. 82. See also on the Class. d'Hist. Nat.' torn. x. p. 324. 
conflicts of this species, Kirby and ^> ' Ann. Soc. Entomolog. France,' 

Spence, ibid. vol. iii. p. 314 ; and 1866, as quoted in ' Journal of 

Westwood, ibid. vol. i. p. 187. Travel,' by A. Murray, 1868, p. 135. 

Chap. :^. 



enormously developed mandibles (fig. '24) ; he is bold and pug- 
nacious ; when threatened he faces round, opens his great jaws, 
and at the same time stridulates loudly. 
But the mandibles were not strong 
enough to pinch my finger so as to 
cause actual pain. 

Sexual selection, which implies the 
possession of considerable perceptive 
powers and of strong passions, seems 
to have been more effective with the 
Lamellicorns than with any other 
family of beetles. With some species 
the males are provided with weapons 
for fighting; some live in pairs and 
show mutual affection ; many have 
the power of stridulating when excited ; 
many are furnished with the most ex- 
traordinary horns, apparently for the 
sake of ornament; and some, which 
are diurnal in their habits, are gor- 
geously coloured. Lastly, several of 
the largest beetles in the world belong 
to this family, which was placed by 
Linnseus and Fabricius at the head of 
the Order.^^ 

Stridulating organs. — Beetles belong- 
ing to many and widely distinct 
families possess these organs. The 
sound thus produced can sometimes 
be heard at the distance of several feet 
or even yards,'^^ but it is not comparable 
with that made by the Orthoptera. 
The rasp generally consists of a narrow, 
slightly-raised surface, crossed by very 
fine, parallel ribs, sometimes so fine as 
to cause iridescent colours, and having 
a very elegant appearance under the 
microscope. In some cases, as Avith 
Typhosus, minute, bristly or scale-like 
prominences, with which the whole 
surrounding surface is covered in approximately parallel 
lines, could be traced passing into the ribs of the rasp. The 

Fi°r. 24. Chiasognathus grantii, 
reduced. U ppcr figure, male ; 
lower figure, female. 

^^ Westwood, 
vol. i. p. 184. 

Modern Class.' 

" Wollaston, ' On certain Musical 

Curculionidaj,' 'Annals and Mag. of 
Nat. Hist.' vol. vi. 18G0, p. 14. 


The Descent of Man. 

Part II. 

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. 

Fig. 25. Necrophorus (from Landois). r. The two rasps, 
the rasp highly magnified. 

Left-hand figure, part of 

These organs are situated in widely different positions. In 
the carrion-beetles (Necrophorus) two parallel rasps (r, fig. 25) 
stand on the dorsal surface of the fifth abdominal segment, each 
rasp^* 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 Crioceridas, 
and in Clylhra ^-punctata (one of the Chrysomehdse), and in some 
Tenebrionidse, &c.,'^^ the rasp is seated on the dorsal apex of the 
abdomen, on the pygidium or pro-pygidium, and is scraped in 
the same manner by the elytra. In Heterocerus, which belongs 
to another family, the rasps are placed on the sides of the 
first abdominal segment, and are scraped by ridges on the 
femora.'^^ In certain Curculionidse and Carabidae,''^ the parts 

^^ Landois, ' Zeitschrift fiir wiss. 
Zoolog.' B. xvii. 1867, s. 127. 

^^ I am greatly indebted to Mr. 
G. R. Crotch for having sent me 
man}^ prepared specimens of various 
beetles belonging to these three 
families and to others, as well as for 
valuable information. He believes 
that the power of stridulation in 
the Clythra has not been previously- 
observed. I am also much indebted 
to Mr. E. W. Janson, for informa- 
tion and specimens. I may add 
that my son, Mr. F. Darwin, finds 
that Dermestes murinus stridulates, 
but he searched in vain for the 
apparatus. Scolytus has lately 

been described by Dr. Chapman as 
a stridulator, in the 'Entomolo- 
gist's Monthly Magazine,' vol. vi. p. 

'^ Schiodte, translated in * Annals 
and Mag. of Nat. Hist.' vol. xx. 
1867, p. 37. 

^^ Westringhas described (Krover, 
' Naturhist. Tidskrift,' B. ii. 1848- 
49, p. 334) the stridulating organs 
in these two, as well as in other 
families. In the Carabidae I have 
examined Elaphrus uliginosus and 
Blethisa multipiinctata, sent to me 
by Mr. Crotch. In Blethisa the 
transverse ridges on the furrowed 
border of the abdominal segment do 

Chap. X. 



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 Pelohius Ileriminni (one of Dytiscidje 
or water-beetles) a strong ridge runs parallel and near to the 
sutural margin of the elytra, and is crossed by ribs, coarse in 
the middle part, but becoming gradually finer at both ends, 
especially at the upper end; when this insect is held under 
water or in the air, a stridulating noise is produced by the 
extreme horny margin of the abdomen being scraped against 
the rasps. In a great number of long-horned beetles (Longi- 
cornia) the organs are situated quite otherwise, the rasp being 
on the meso-thorax, which is rubbed against the pro-thorax; 
Landois counted 238 very fine ribs on the rasp of Ceramhyx 

Many Lamellicorns have the power of stridulating, and the 
organs differ greatly in position. Some species stridulate very 
loudly, so that when Mr. F. Smith caught a Trox sahidosus, 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 Typhoeus a 
narrow ridge runs obliquely across (r, fig. 2G) 
the coxa of each hind-leg (having in G. ster- 
corarius 84 ribs), which is scraped by a 
specially projecting part of one of the ab- 
dominal segments. In the nearly allied Copris 
lunaris, an excessively narrow fine rasp runs 
along the sutural margin of the elytra, with 
another short rasp near the basal outer mar- 
gin; but in some other Coprini the rasp is 
seated, according to Leconte,'^^ on the dorsal 
surface of the abdomen. In Oryctes it is 
seated on the pro-pygidium ; and, according to 
the same entomologist, in some other Dynastini, 
on the under surface of the elytra. Lastly, 
Westring states that in Omaloplia hrunnea the 
rasp is placed on the pro-sternum, and the 
scraper on the meta-sternum, the parts thus 
occupying the under surface of the body, instead of the upper 
surface as in the Longicorns. 

We thus see that in the different coleopterous families the 

not, as far as I could judge, come of Illinois, for having sent me ex- 

into play in scraping the rasps on tracts from Leconte's ' Introduction 

the elytra. to Entomology,' pp. 101, 143. 
" 1 am indebted to Mr. Walsh, 

ip. 26. Hind-leg of 
Gp(jtrnpcs storcora- 
rius (from Landois). 

, Rasp. c. Coxa. /. 
Femur, t. Tibia 
tr. Tarsi. 

304 The Descent of Man. Paet II. 

stridulating organs are wonderfully diversified in position, but 
not much in structure. Within the same family some species 
are provided with these organs, and others are destitute of them. 
This diversity is intelligible, if we suppose that originally various 
beetles made a shuffiing or hissing noise by the rubbing together 
of any hard and rough parts of their bodies, which happened to 
be in contact ; and that from the noise thus produced being in 
some way useful, the rough surfaces were gradually developed 
into regular stridulating organs. Some beetles as they move, 
now produce, either intentionally or unintentionally, a shuffling 
noise, without possessing any proper organs for the purpose. 
Mr. Wallace infoims me that the Euchirus longimanus (a 
Lamellicorn, with the anterior legs wonderfully elongated in the 
male) " makes, whilst moving, a low hissing sound by the pro- 
'* trusion and contraction of the abdomen ; and when seized it 
" produces a grating sound by rubbing its hind-legs against the 
" edges of the elytra." The hissing sound is clearly due to a 
narrow rasp running along the sutural margin of each elytron ; 
and I could likewise make the grating sound by rubbing the 
shagreened surface of the femur against the granulated margin 
of the corresponding elytron ; but I could not here detect any 
proper rasp ; nor is it hkely that I could have overlooked it in 
so large an insect. After examining Cychrus, and reading what 
Westring has written about this beetle, it seems very doubtful 
whether it possesses any true rasp, though it has the power of 
emitting a sound. 

From the analogy of the Orthoptera and Homoptera, I 
expected to find the stridulating organs in the Coleoptera 
differing according to sex; but Landois, who has carefully 
examined several sjDecies, observed no such difference ; nor did 
Westring; nor did Mr. G. E. Crotch in preparing the many 
specimens which he had the kindness to send me. Any difference 
in these organs, if slight, would, however, be difficult to detect, 
on account of their great variability. Thus, in the first pair of 
specimens of Necrophorus humafor and of Pelohius which I ex- 
amined, the rasp was considerably larger in the male than in 
the female; but not so with succeeding specimens. In Geo- 
triipes stercorarius the rasp appeared to me thicker, opaquer, 
and more prominent in three males than in the same number of 
females; in order, therefore, to discover whether the sexes 
differed in their power of stridulating, my soa, Mr. F. Darwin, 
collected fifty-seven living specimens, which he separated into two 
lots, according as they made a greater or lesser noise, when held 
in the same manner. He then examined all these specimens, 
and found that the males were very nearly in the same proportion 

Chap. X. Coleoptera. 305 

to the females in both the lots. Mr. F. Smith has kept alive 
inimerous specimens of Monoijnclms pseudacoH (Cnrculiomda}), 
and is convinced that both sexes stridulate, and apparently in 

an equal degree. . , . ^ ^ 

Nevertheless, the power of stridulating is certainly a sexual 
character in some few Coleoptera. Mr. Crotch discovered that 
the males alone of two species of Heliopathes (TenebrionidsB) 
possess stridulating organs. I examined live males of 11. (jlhhiis, 
and in all these there was a well-developed rasp, partially 
divided into two, on the dorsal suriace of the terminal abdominal 
•sef'-ment ; whilst in the same number of females there was not 
even a rudiment of the rasp, the membrane of this segment 
being transparent, and much thinner than in the male. In 
H cribratostriatus the male has a similar rasp, excepting that it 
is not partially divided into two portions, and the female is 
completely destitute of this organ; the male in addition has on 
the apical margins of the elytra, on each side of the suture, 
three or four short longitudinal ridges, which are crossed by 
extremely fine ribs, parallel to and resembling those on the 
abdominal rasp; whether these ridges serve as an independent 
rasp, or as a scraper for the abdominal rasp, I could not decide: 
the female exhibits no trace of this latter structure. 

Ao-ain, in three species of the Lamellicorn genus Oryctes, we 
have a nearly parallel case. In the females of 0. gryphus and 
nasicornis the ribs on the rasp of the pro-pygidmm are less 
continuous and less distinct than in the males; but the chief 
difference is that the whole upper surface of this segment, when 
held in the proper light, is seen to be clothed with hairs, which 
are absent or are represented by excessively fine down m the 
males. It should be noticed that in all Coleoptera the effective 
part of the rasp is destitute of hairs. In 0. senegalensts the 
difference between the sexes is more strongly marked, and this 
is best seen when the proper abdominal segment is cleaned and 
viewed as a transparent object. In the female the whole surface 
is covered with little separate crests, bearing spines ; whilst m 
the male these crests in proceeding towards the apex, become 
more and more confluent, regular, and naked; so that three- 
fourths of the segment is covered with extremely fine parallel 
ribs which are quite absent in the female. In the females, 
however, of all three species of Oryctes, a slight grating or 
Gtridulating sound is produced, when the abdomen of a softened 
.specimen is pushed backwards and forwards. 

In the case of the Heliopathes and Oryctes there can hardly 
be a doubt that the males stridulate in order to call or to 
excite the females; but with most beetles the stridulation 

306 The Desceftt of Man. Pakt II. 

apparently serves both sexes as a mntual call. Beetles striclu- 
late under various emotions, in the same manner as birds use 
their voices for many purposes besides singing 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. Wollaston and Crotch were able to 
discover the presence of beetles belonging to the genus Acalles 
by their stridulation. Lastly, the male Ateuchus stridulates to 
encourage the female in her work, and from distress when she 
is removed.'^^ Some naturalists believe that beetles make this 
noise to frighten away their enemies ; but I cannot think that 
a quadruped or bird, able to devour a large beetle, would 
be frightened by so slight a sound. The belief that the stridu- 
lation serves as a sexual call is supported by the fact that death- 
ticks {Anohium tessellatuni) are well known to answer each 
other's ticking, and, as I have myself observed, a tapping noise 
artificially made. Mr. Doubleday also informs me that he 
has sometimes observed a female ticking,^" and in an hour or 
two afterwards has found her united with a male, and on one 
occasion surrounded by several males. Finally, it is probable 
that the two sexes of many kinds of beetles were at first 
enabled to find each other by the slight shuffling noise produced 
by the rubbing together of the adjoining hard parts of their 
bodies; and that as those males or females which made the 
greatest noise succeeded best in finding partners, rugosities on 
various parts of their bodies were gradually developed by means 
of sexual selection into true stridulating organs. 

^® M. P. de la Brulerie, as quoted Landois, ' Zeitschrift fiir wissen. 

in 'Journal of Travel,' A. Murray, Zoolog.' B. xvii. s. 131. Oliver 

vol. i. 1868, p. 135. says (as quoted by Kirby and 

'" According to Mr. Doubleday, Spence, ' Introduct.' vol. ii. p. 395) 

" the noise is produced by ihe in- that the female of Pimelia striata 

" sect raising itself on its legs as produces a rather loud sound by 

" high as it can, and then striking striking her abdomen against any 

" its thorax five or six times, in hard substance, " and that the male, 

*' rapid succession, against the sub- " obedient to this call, soon attends 

" stance upon which it is sitting." " her, and they pair." 
For references on this subject see 

Chap. XI. Biitterjiies and Moths. 307 

Insects, continued. — Order Lepidoptera. 

(butterflies and moths.) 

Courtship of butterflies— Battles — Ticking noise— Colours conimon to 
both feexes, or more brilliant in the males — Examples — Not due to the 
direct action of the conditions of life — Colours adapted for protection — 
Colours of moths— Display — Perceptive powers of the Lepidoptera — 
Variability — Causes of the difference in colour between the males and 
females— Mimicry, female butterflies more brilliantly coloured than 
the males — Bright colours of caterpillars — Summary and concluding 
remarks on the secondary sexual characters of insects — Birds and insects 

In this great Order the most interesting points for us are the 
differences in colour between the sexes of the same species, and 
between the distinct species of the same genus. Nearly the 
whole of the following chapter will be devoted to this subject ; 
but I will first make a few remarks on one or two other points. 
Several males may often be seen pursuing and crowding round 
the same female. Their courtship appears to be a prolonged 
affair, for I have frequently watched one or more males pirouet- 
ting round a female until I was tired, without seeing the 
end of the courtship. Mr. A. G. Butler also informs me that 
he has several times watched a male courting a female for a full 
quarter of an hour ; but she pertinaciously refused bim, and at 
last settled on the ground and closed her wings, so as to escape 
from his addresses. 

Although butterflies are weak and fragile creatures, they are 
pugnacious, and an Emperor butterfly ^ has been captured with 
the tips of its wings broken from a conflict with another male. 
Mr. Collingwood, in speaking of the frequent battles between the 
butterflies of Borneo, says, " They whirl round each other with 
" the greatest rapidity, and appear to be incited by the greatest 
" ferocity." 

The Ageronia feronia makes a noise like that produced by a 
toothed wheel passing under a spring catch, and which can be 
heard at the distance of several yards : I noticed this sound at 
Eio de Janeiro, only when two of these butterflies were chasing 
each other in an irregular course, so that it is probably made 
during the courtship of the sexes.^ 

1 Apatura Iris: 'The Entomolo- Natura-list,' 18G8, p. IS.'), 
gist's Weekly Intelligence,' 1859, p. ^ gee my 'Journal of Researches,' 

139. For the Bornean Butterflies, 1845, p. 33. Mr. Doubleday has 
6e« C. Collingwood, ' Rambles of a detected (' Proc. Ent. See' March 

3o8 The Descent of Man. Part II. 

Some moths also produce sounds ; for instance, the males of 
Thecophora fovea. On two occasions Mr. F. Buchanan White ^ 
heard a sharp quick noise made by the male of Hylophila 
jjrasinana, and which he believes to be produced, as in Cicada, 
by an elastic membrane, furnished with a muscle. He quotes, 
also, Guenee, that Setina produces a sound like the ticking 
of a watch, apparently by the aid of " two large tympaniform 
" vesicles, situated in the pectoral region ; " and these " are much 
" more developed in the male than in the female." Hence the 
sound-producing organs in the Lepidoptera appear to stand in 
some relation with the sexual functions. I have not alluded 
to the well-known noise made by the Death's Head Sphinx, for 
it is generally heard soon after the moth has emerged from 
its cocoon. 

Girard has always observed that the musky odour, which is 
emitted by two species of Sphinx moths, is peculiar to the males ;^ 
and in the higher classes we shall meet with many instances of 
the males alone being odoriferous. 

Every one must have admired the extreme beauty of many 
butterflies and of some moths ; and it may be asked, are their 
colours and diversified patterns the result of the direct action of 
the i)hysical conditions to which these insects have been exposed, 
without any benefit being thus derived ? Or have successive 
variations been accumulated and determined as a protection, 
or for some unknown purpose, or that one sex may be at- 
tractive to the other ? And, again, what is the meaning of the 
colours being widely different in the males and females of 
certain siDccies, and alike in the two sexes of other species of the 
same genus ? Before attempting to answer these questions a 
body of facts must be given. 

With our beautiful English butterflies, the admiral, peacock, 
and painted lady (Vanessse), as well as many others, the sexes 
are alike. This is also the case with the magniflcent Heliconidae, 
and most of the Danaidse in the tropics. But in certain other 
tropical groups, and in some of our English butterflies, as the 
purple emperor, orange-tip, &c. {Apatura Iris and Anthocharis 
cardamines), the sexes differ either greatly or slightly in colour. 
No language suffices to describe the splendour of the males of 

3rd, 1845, p. 123) a peculiar mem- observations, * The Scottish Natural- 

branous sac at the base of the ist,* July 1872, p. 214. 

front wings, which is probably con- ^ ' The Scottish Naturalist,' July 

nected with the production of the 1872, p. 213. 

sound. For the case of Thecophora, * ' Zoological Record,' 1869, p. 

see 'Zoological Record,' 1869, p. 347. 

401. For Mr. Buchanan White's 

Chap. XL Butterflies and Moths. 309 

some tropical species. Even within the same genus Ave often 
find species presenting extraordinary differences between the 
sexes, whilst others have their sexes closely alike. Thns in the 
South American genus Epicalia, Mr. Bates, to whom I am 
indebted for most of the following facts, and for looking over 
this whole discussion, informs me that he knows twelve species, 
the two sexes of which haunt the same stations (and this is not 
always the case with butterflies), and which, therefore, cannot 
have been differently affected by external conditions.^ In nine of 
these twelve species the males rank amongst tlie most brilliant of 
all butterflies, and differ so greatly from the comparatively plain 
females that they were formerly placed in distinct genera. The 
females of these nine species resemble each other in their general 
type of coloration; and they likewise resemble both sexes of 
the species in several alhed genera, found in various parts of 
the world. Hence we may infer that these nine species, and 
probably all the others of the genus, are descended from an 
ancestral form which was coloured in nearly the same manner. 
In the tenth species the female still retains the same general 
colouring, but the male resembles her, so that he is coloured in 
a much less gaudy and contrasted manner than the males of the 
previous species. In the eleventh and twelfth species, the 
females depart from the usual type, for they are gaily decorated 
almost like the males, but in a somewhat less degree. Hence in 
these two latter species the bright colours of the males seem to 
have been transferred to the females ; whilst in the tenth 
species the male has either retained or recovered the plain 
colours of the female, as well as of the parent-form of the genus. 
The sexes in these three cases have thus been rendered nearly 
alike, though in an opposite manner. In the allied genus Eubagis, 
both sexes of some of the species are plain-coloured and nearly 
alike ; whilst with the greater number the males are decorated 
with beautiful metallic tints in a diversified manner, and differ 
much from their females. The females throughout the genus 
retain the same general style of colouring, so that they resemble 
one another much more closely than they resemble their own 

In the genus Papilio, all the species of the ^neas group 
are remarkable for their conspicuous and strongly contrasted 
colours, and they illustrate the frequent tendency to gradation 
in the amount of difference between the sexes. In a few species, 
for instance in P. ascauius, the males and females are alike ; in 

* See also Mr. Bates's paper in the same subject, in regard to 
♦ Proc. Ent. Soc. of Philadelphia,' Diadema, in ' transact. Entomolog. 
1865, p. 206. Also Mr. Wallace on Soc. of London,' 1869, p. 278. 

3IO The Descent of Mail. Part II. 

others the males are either a little brighter, or very much more 
superb than the females. The genus Juuouia, allied to our 
Vaness?e, offers a nearly parallel case, for although the sexes of 
most of the species resemble each other, and are destitute of 
rich colours, yet in certain species, as in J. cenone, the male is 
rather more bright- coloured than the female, and in a few (for 
instance J. andremiaja) the male is so different from the female 
that he might be mistaken for an entirely distinct species. 

Another striking case was pointed out to me in the British 
Museum by Mr. A. Butler, namely, one of the tropical American 
Theclse, in which both sexes are nearly alike and wonderfully 
splendid ; in another species the male is coloured in a similarly 
gorgeous manner, whilst the whole upper surface of the 
female is of a dull uniform brown. Our common little English 
blue butterflies of the genus Lyc^na, illustrate the various dif- 
ferences in colour between the sexes, almost as well, though not 
in so striking a manner, as the above exotic genera. In Lycxna 
agestis both sexes have wings of a brown colour, bordered with 
small ocellated orange spots, and are thus alike. In L. csgon 
the wings of the male are of a fine blue, bordered with black ; 
whilst those of the female are brown, with a similar border, 
closely resembling the wings of X. agestis. Lastly, in L. arion both 
sexes are of a blue colour and are very like, though in the female 
the edges of the wings are rather duskier, with the black spots 
plainer ; and in a bright blue Indian sj^ecies both sexes are still 
more alike. 

I have given the foregoing details in order to show, in the first 
place, that when the sexes of butterflies differ, the male as a 
general rule is the more beautiful, and departs more from the 
usual type of colouring of the group to which the species 
belongs. Hence in most groups the females of the several 
species resemble each other much more closely than do the 
males. In some cases, however, to which I shall hereafter 
allude, the females are coloured more splendidly than the 
males. In the second place, these details have been given to 
bring clearly before the mind that within the same genus, the 
two sexes frequently present every gradation from no difference 
in colour, to so great a difference that it was long before the two 
were placed by entomologists in the same genus. In the third 
l^lace, we have seen that when the sexes nearly resemble each 
other, this appears due either to the male having transferred 
his colours to the female, or to the male having retained, or 
perhaps recovered, the jr-rimordial colours 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 

Chap. XI. Btittei'Jlies and Aloths. 311 

the males cire beautiful to an extraordinary degree, the females 
almost invariably exhibit some degree of beauty. From the 
many cases of gradation in the amount of difference between 
the sexes, and from the prevalence of the same general type of 
coloration throughout the whole of the same group, we may con- 
clude that the causes have generally been the same which have 
determined the brilliant colouring of the males alone of some 
species, and of both sexes of other species. 

As so many gorgeous butterflies inhabit the tropics, it has 
often been supposed that they owe their colours to the great 
heat and moisture of these zones ; but Mr. Bates ° has shewn by 
the comparison of various closely-allied groups of insects from 
the temperate and tropical regions, that this view cannot be 
maintained ; and the evidence becomes conclusive wlien bril- 
liantly-coloured males and plain-coloured females of the same 
species inhabit the same district, feed on the same food, and 
follow exactly the same habits of life. Even when the sexes 
resemble each other, we can hardly believe that their brilliant 
and beautifully-arranged colours are the purposeless result of 
the nature of the tissues and of the action of the surrounding 

With animals of all kinds, whenever colour has been modified 
for some special purpose, this has been, as far as we can judge, 
either for direct or indirect protection, or as an attraction between 
the sexes. With many species of butterflies the upper surfaces 
of the wings are obscure; and this in all probability leads 
to their escaping observation and danger. But butterflies 
would be particularly liable to be attacked by their enemies 
when at rest ; and most kinds whilst resting raise their wings 
vertically over their backs, so that the lower surface alone is 
exposed to view. Hence it is this side which is often coloured 
so as to imitate the objects on which these insects commonly 
rest. Dr. Bossier, I believe, first noticed the similarity of the 
closed wings of certain Vanesste 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 antennae between its closed wings, which, 
in form, colour and veining, cannot be distinguished from a 
withered leaf with its footstalk. In some other cases the lower 

« 'The Naturalist on the Ama- 18G7, p. 10. A woodcut of the 

zons,' vol. i. 1863, p. 19. Kallima is given by Mr. Wallace in 

^ See the interesting article in ' Hardwicke's Science Gossip,' Sept. 

the ' Westminster Review,* July 18G7, p. 19G. 

312 The Descent of Man. Part 11. 

surfaces of the wings are brilliantly coloured, and yet are 
protective ; thus in Theda ruhi the Avings when closed are of an 
emerald green, and resemble the young leaves of the bramble, 
on which in spring this butterfly may often be seen seated. It is 
also remarkable that in very many species in which the sexes 
differ greatly in colour on their upper surface, the lower surface 
is closely similar or identical in both sexes, and serves as a 

Although the obscure tints both of the up])er and under 
sides of many butterflies no doubt serve to conceal them, yet we 
cannot extend this view to the brilliant and conspicuous colours 
on the upper surface of such species as our admiral and peacock 
Yanessge, our white cabbage-butterflies (Pieris), or the great 
swallow-tail Papilio which haunts the open fens — for these 
butterflies are thus rendered visible to every living creature. 
In these species both sexes are alike ; but in the common brim- 
stone butterfly (Gonepteryx rhamni), the male is of an intense 
yellow, whilst the female is much paler; and in the orange- 
tip (Anthocharis cardamines) the males alone have their wings 
tipped with bright orange. Both the males and females in 
these cases are conspicuous, and it is not credible that their 
difference in colour should stand in any relation to ordinary 
protection. Prof. Weismann remarks,^ that the female of one of 
the Lycsense expands her brown wings when she settles on 
the ground, and is then almost invisible ; the male, on the other 
hand, as if aware of the danger incurred from the bright blue of 
the upper surface of his wings, rests with them closed ; and this 
shews that the blue colour cannot be in any way protective. 
Nevertheless, it is probable that conspicuous colours are in- 
directly beneficial to many species, as a warning that they are 
unpalatable. For in certain other cases, beauty has been gained 
through the imitation of other beautiful species, which inhabit 
the same district and enjoy an immunity from attack by being 
in some way offensive to their enemies ; but then we have to 
account for the beauty of the imitated species. 

As Mr. Walsh has remarked to me, the females of our orange- 
tip butterfly, above referred to, and of an American species 
{Anth. genutia) probably shew us the primordial colours of the 
parent-species of the genus; for both sexes of four or five 
widely-distributed species are coloured in nearly the same 
manner. As in several previous cases, we may here infer that 
it is the males of Anth. cai'damines and genutia which have 
departed from the usual type of the genus. In the Anth. sara 

8 Mr. G. Fraser, in ' Nature,' » ' Einfluss der Isolirung auf die 

April 1871, p. 489. Artbildung,' 1872, p. 58. 

Chap. XI. BiUterflies and Moths. 313 

from California, the orange-tips to the wings have been partially 
developed in the female ; but they are paler than in the male, and 
slightly different in some other respects. In an allied Indian 
form, the Iphias glaucippe, the orange-tips are fully developed in 
both sexes. In this Iphias, as pointed out to me by Mr. A. Butler, 
the under surface of the wings marvellously resembles a pale- 
coloured leaf; and in our English orange-tip, the under surface 
resembles the flower-head of the wild parsley, on which the 
butterfly often rests at night.^*^ The same reason which compels 
us to believe that the lower surfaces have here been coloured for 
the sake of protection, leads us to deny that the wings have 
been tipped with bright orange for the same purpose, especially 
when this character is confined to the males. 

Most Moths rest motionless during the whole or gi-eater pai-t 
of the day with their wiDgs depressed ; and the whole upper 
surface is often shaded and coloured in an admirable manner, as 
Mr. Wallace has remarked, for escaping detection. The front- 
wings of the Bombycidae and Noctuidse,^^ when at rest, generally 
overlap and conceal the hind- wings ; so that the latter might be 
brightly coloured without much risk; and they are in fact 
often thus coloured. During flight, moths would often be able 
to escape from their enemies ; nevertheless, as the hind-wings 
are then fully exposed to view, their bright colours must 
generally have been acquired at some little risk. But the 
following fact shews how cautious we ought to be in drawing 
conclusions on this head. The common Yellow Under- wings 
(Triphsena) often fly about during the day or early evening, and 
are then conspicuous from the colour of their hind-wings. It 
would naturally be thought that this would be a source of 
danger ; but Mr. J. Jenner Weir believes that it actually serves 
them as a means of escape, for birds strike at these brightly 
coloured and fragile surfaces, instead of at the body. For in- 
stance, Mr. Weir turned into his aviary a vigorous specimen of 
Triphcena pronuba, which was instantly pursued by a robin; 
but the bird's attention being caught by the coloured wings, the 
moth was not captured until after about fifty attempts, and 
small portions of the wings were repeatedly broken off. He tried 
the same experiment, in the open air, with a swallow and T. 
fimbria', but the large size of this moth probably interfered 
with its capture.^^ We are thus reminded of a statement made 

'0 See the interesting observatious Science Gossip,' Sept. 18G7, p. 193. 
hy Mr. T. W. Wood, ' The Student,' i^ g^g j^jgo, on this subject, Mr. 

Sept. 1868, p. 81. Weir's paper in 'Transact. Eut. Soc' 

•1 Mr. Walhice in ' Hardwicke's 1869, p. 23. 

314 The Descent of Man. Part II. 

by Mr. Wallace,^^ namely, that in the Brazihan 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 in- 
" directly beneficial." 

Display. — The bright colours of many butterflies and of some 
moths are specially arranged for display, so that they may be 
readily seen. During the night colours are not visible, and 
there can be no doubt that the nocturnal moths, taken as a 
body, are much less gaily decorated than butterflies, all of 
which are diurnal in their habits. But the moths of certain 
families, such as the Zygsenidas, several Sphingidse, Uraniidai 
some Arctiidse and Saturniidse, fly about during the day or 
early evening, and many of these are extremely beautiful, being 
far brighter coloured than the strictly nocturnal kinds. A 
few exceptional cases, however, of bright-coloured 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 whilst basking in the sunshine often alternately raise 
and depress them, thus exposing both surfaces to full view ; and 
although the lower surface is often coloured in an obscure 
manner as a protection, yet in many species it is as highly 
decorated as the upper surface, and sometimes in a very 
different manner. In some tropical species the lower surface is 
even more brilliantly coloured than the upper. ^^ In the Eng- 
lish fritillaries (Argynnis) the lower surface alone is orna- 
mented with shining silver. Nevertheless, as a general rule, 
the upjxir surface, which is probably more fully exposed, is 
coloured more brightly and diversely than the lower. Hence 
the lower surface generally affords to entomologists the more 

13 < Westminster Review,' July Insects of New England,' 184-2, p. 315. 
1867, p. 16. ^^ Such differences between the 

^* For instance, Lithosia ; but upper and lower surfoces of the 

Prof. Westwood (' Modern Class, of wings of several species of Papilio, 

Insects,' vol. ii. p. 390) seems sur- may be seen in the beautiful plates 

prised at this case. On the relative to Mr. Wallace's ' Memoir on the 

colours of diurnal and nocturnal Papilionidae of the Malayan Region," 

Lepidoptera, see ibid. pp. 333 and in 'Transact. Linn. Soc' vol. xxv. 

392; also Harris, 'Treatise on the part i. 1865. 

Chap. XL Butterflies and Moths. 3 1 5 

useful character for detecting the affinities of the various 
species, Fritz Mliller informs me that three species of Castnia 
are found near his house in S. Brazil : of two of them the hind- 
wings are obscure, and are always covered by the front- 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 
coloured with a brightness greater than, or even equal to, that 
of the upper side. Some exceptions to the rule, either real or 
apparent, must be noticed, as the case of Hypopyra.^^ Mr. 
Trimen informs me that in Guenee's great work, three moths 
are figured, in which the under surface is much the more 
brilliant. For instance, in the Australian Gastrophora the 
upper surface of the fore-wing is pale greyish-ochreous, while 
the lower surface is magnificently ornamented by an ocellus of 
cobalt-blue, placed in the midst of a black mark, surrounded 
by orange-yellow, and this by bluish-wliite. But the habits of 
these three moths are unknown ; so that no explanation can be 
given of their unusual style of colouring. Mr. Trimen also 
informs me that the lower surface of the wings in certain other 
Geometrse" and quadrifid Noctuse are either more variegated 
or more brightly-coloured than the upper surface ; but some of 
these species have the habit of " holding their wings quite erect 
" over their backs, retaining them in this position for a con- 
" siderable time," and thus exposing the under surface to view. 
Other species, when settled on the ground or herbage, now and 
then suddenly and slightly lift up their wings. Hence the lower 
surface of the wings being brighter than the upper surface 
in certain moths is not so anomalous as it at first appears. 
The Saturniidae include some of the most beautiful of all 
moths, their wings being decorated, as in our British Emperor 
moth, with fine ocelli ; and Mr. T. W. "VVood^* 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 tlian of 
** nocturnal Lepidoptera." 

" See Mr. Wormald on this the Geometra}) in 'Transact. Eut. 

moth : ' Proc. Ent. Soc' March 2nd, Soc' new series, vol. v. pi. xv. and 

1868. xvi. 

1' See also an account of the S. ^^ ' Proc. Ent. Soc. of London,' 

American genus Erateina (one of July 6, 18(38, p. xxvii. 

3i6 T lie Descent of Man. Part II. 

It is a singular fact that no British moths which are bril- 
liantly coloured, and, as far as I can discover, hardly any foreign 
species, differ much in colour according to sex ; though this is 
the case with many brilliant butterflies. The male, however, of 
one American moth, the Saturnia lo, is described as having its 
fore-wings deep yellow, curiously marked with purplish-red 
spots ; whilst the wings of the female are purple-brown, marked 
with grey lines.^^ The British moths which differ sexually in 
colour 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 grouj^s which generally fly about 
during the afternoon. On the other hand, in many genera, as 
Mr. Stainton informs me, the males have the hind- wings whiter 
than those of the female — of which fact Agrotis exdamationis 
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 whilst flying about in 
the dusk. 

From the several foregoing facts it is impossible to admit 
that the brilliant colours of butterflies, and of some few moths, 
have commonly been acquired for the sake of protection. We 
have seen that their colours and elegant patterns are arranged 
and exhibited as if for display. Hence I am led to believe that 
the females prefer or are most excited by the more brilliant 

^^ Harris, ' Treatise,' <S:c., edited which were fond of eating other 

by Flint, 1862, p. 395. moths ; so that if the Cycnia was 

2° For instance, I observe in my commonly mistaken by British birds 

son's cabinet that the males are for the Spilosoma, it would escape 

darker than the females in the being devoured, and its white de- 

Lasiocampa quercus, Odonestis pota- ceptive colour would thus be highly 

toria, Hypogymnt dispar, Dasychira beneficial. 

pudibunda, and Cycnia mendica. In ^^ It is remarkable, that in the 
this latter species the difference in Shetland Islands the male of this 
colour between the two sexes is moth, instead of differing widely 
strongly marked ; and Mr. Wallace from the female, frequently re- 
informs me that we here have, as sembles her closely in colour (see 
he believes, an instance of protective Mr. MacLachlan, ' Transact. Ent. 
mimicry confined to one sex, as Soc' vol. ii. 1866, p. 459). Mr. 
will hereafter be more fully ex- G. Fraser suggests ('Nature,' April 
plained. The white female of the 1871, p. 489) that at the season of 
Cycnia resembles the very common the year when the ghost-moth ap- 
Spilosoma menthrasti, both sexes of pears in these northern islands, the 
which are white ; and Mr. Stainton whiteness of the males would not 
observed that this latter moth was be needed to render them visible tc 
rejected with utter disgust by a the females in the twilight night, 
whole brood of young turkeys, 

Chap. XL Biittcrjiies and MotJis. 317 

males ; for on any other supposition the males would, as far as 
sve can see, be ornamented to no purpose. We know that ants 
and certain Lamellicorn beetles are capable of feeling an attach- 
ment for each other, and that ants recognise their tellows after 
an interval of several months. Hence there is no abstract 
improbability in the Lepidoptcra, which probably stand nearly 
or quite as high in the scale as these insects, having sufficient 
mental capacity to admire bright colours. They certainly 
discover flowers by colour. The Humming-bird Sphinx may 
often be seen to swoop down from a distance on a bunch of 
flowers in the midst of green foliage ; and I have been assured 
by two persons, that these moths repeatedly visit flowers 
painted on the walls of a room, and vainly endeavour to insert 
their proboscis into them. Fritz Miiller informs me that several 
kinds of butterflies in S. Brazil shew an unmistakable prefer- 
ence for certain colours over others : he observed that they 
very often visited the brilliant red flowers of five or six genera of 
plants, but never the white or yellow flowering species of the 
same and other genera, growing in the same garden ; and I 
have received other accounts to the same efl"ect. 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 " a dead specimen pinned upon a 
" conspicuous twig will often arrest an insect of the same species 
" in its headlong flight, and bring it down within easy reach of 
*' the net, especially if it be of the opposite sex." 

The courtship of butterflies is, as before remarked, a prolonged 
affair. The males sometimes fight together in rivalry; and 
many may be seen pursuing or crowding round the same 
female. Unless, then, the females prefer one male to another, 
the pairing must be left to mere chance, and this does not 
appear probable. If, on the other hand, the females habitually, 
or even occasionally, prefer the more beautiful males, the colours 
of the latter will have been rendered brighter by degrees, and 
will have been transmitted to both sexes or to one sex, according 
to the law of inheritance which has prevailed. The process of 
sexual selection will have been much facilitated, if the conclusion 
can be trusted, arrived at from various kinds of evidence in the 
supplement to the ninth chapter; namely, that the males of 
many Lepidoptera, at least in the imago state, greatly exceed 
the females in number. 

Some facts, however, are opposed to the belief that female 

" 'Rambles of a Naturalist in the Chinese Seas,' 1868, p. 182. 

3 1 8 The Descent of Man. Part II. 

butterflies prefer tlio more beautiful males ; thus, as 1 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 Bombycidae, the sexes pair 
immediately after assuming the imago state; for they cannot 
feed, owing to the rudimentary condition of their mouths. The 
females, as several entomologists have remarked to me, lie in an 
almost torpid state, and appear not to evince the least choice in 
regard to their partners. This is the case with the common 
silk-moth (^B. morl), as I have been told by some continental 
and English breeders. Dr. Wallace, who has had great 
experience in breeding Bomhyx cynthia, is convinced that the 
females evince no choice or preference. He has kept above 
300 of these moths together, and has often found the 
most vigorous females mated with stunted males. The reverse 
appears to occur seldom ; for, as he believes, the more vigorous 
males pass over the weakly females, and are attracted by those 
endowed with most vitality. Nevertheless, the Bombycidse, 
though obscurely-coloured, are often beautiful to our eyes from 
their elegant and mottled shades. 

I have as yet only referred to the species in which the males 
are brighter coloured than the females, and I have attributed 
their beauty to the females for many generations having chosen 
and paired with the more attractive males. But converse 
cases occur, though rarely, in which the females are more 
brilliant than the males ; and here, as I believe, the males have 
selected the more beautiful females, and have thus slowly added 
to their beauty. We do not know why in various classes of 
animals the males of some few sjDecies 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. 
Butler shewed me several species of Callidryas in the British 
Museum, in some of which the females equalled, and in others 
gi-eatly surpassed the males in beauty; for the females alone 
have the borders of their wings suffused with crimson and 
orange, and spotted with black. The plainer males of these 
species closely resemble each other, showing that here the 
females have been modified ; whereas in those cases, where the 
males are the more ornate, it is these which have been modified, 
the females remaining closely alike. 

Chap. XL Butterflies a7id Moths, 319 

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 Hip- 
parchia the sexes do not differ much ; but it is the female of 
H. janira which has a conspicuous light-brown patch on her 
wings ; and the females of some of the other species are brighter 
coloured than their males. Again, the females of CoJias ednsa 
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 
commonly take the more active share in wooing, and their 
beauty seems to have been increased by the females having 
accepted the more attractive individuals ; but with these but- 
terflies, the females take the more active part in the final mar- 
riage ceremony, so that we may suppose that they likewise do 
so in the wooing ; and in this case we can understand how it is 
that they have been rendered the more beautiful. Mr. Meldola, 
from whom the foregoing statements have been taken, sajs in 
conclusion ; " Though I am not convinced of the action of 
" sexual selection in producing the colours of insects, it cannot 
" be denied that these facts are strikingly corroborative of 
" Mr. Darwin's views." ^^ 

As sexual selection primarily depends on variability, a few 
words must be added on this subject. In respect to colour 
there is no difficulty, for any number of highly variable Lepi- 
doptera could be named. One good instance will suffice. Mr. 
Bates shewed me a whole series of specimens of Papilio sesostris 
and F. childrence : in the latter the males varied much in the 
extent of the beautifully enamelled green patch on the fore- 
wings, and in the size of the white mark, and of the splendid 
crimson stripe on the hind- wings ; so that there was a great 
contrast amongst the males between the most and the least 
gaudy. The male of Papilio sesostris is much less beautiful 
than of P. childrence: and it likewise varies a little in the size of 

23 'Nature,' April 27th, 1871, p. whilst pairing. See also Mr. G. 

508, Mr. Meldola quotes Donzel, Fraser, in ' Nature,' April 20th, 

in 'Soc. Ent. de France,' 1837, p. 1871, p. 489, on the sexual differ- 

77, on the flight of butterflies ences of several British butterflies. 

320 The Descent of Man. Pakt II. 

the green patcli on the fore-wings, and in the occasional ap- 
pearance of the small crimson stripe on the hind-wings, 
borrowed, as it would seem, from its own female ; for the females 
of this and of many other species in the ^neas group possess 
this crimson stripe. Hence between the brightest specimens 
of P. sesostris and the dullest of P. chiklrence, there was but a 
small interval ; and it was evident that as far as mere varia- 
bility is concerned, there would be no difficulty in permanently 
increasing the beauty of either species by means of selection. 
The variability is here almost confined to the male sex; but 
Mr. Wallace and ]\Ir. Bates have shewn ^^ that the females of 
some species are extremely variable, the males being nearly 
constant. In a future chapter I shall have occasion to shew 
that the beautiful eye-like spots, or ocelli, found on the wings of 
many Lepidoptera, are eminently variable. I may here add 
that these ocelli offer a difficulty on the theory of sexual 
selection ; for though appearing to us so ornamental, they are 
never present in one sex and absent in the other, nor do they 
ever differ much in the two sexes.^^ This fact is at present 
inexphcable ; but if it should hereafter be found that the for- 
mation of an ocellus is due to some change in the tissues 
of the wings, for instance, occui'ring 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 coloured 
species of Lepidoptera owe their colours to sexual selection, 
excepting in certain cases, presently to be mentioned, in which 
conspicuous colours have been gained through mimicry as 
a protection. From the ardour of the male throughout the 
animal kingdom, he is generally willing to accept any female ; 
and it is the female which usually exerts a choice. Hence, if 
sexual selection has been efficient with the Lepidoptera, the 
male, when the sexes differ, ought to be the more brilliantly 
coloured, and this undoubtedly is the case. When both sexes 
are brilliantly coloured and resemble each other, the characters 
acquired by the males appear to have been transmitted to both. 

2* Wallace on the Papilionida; of tomolog. Soc' Nov. 19th, 1866, p. 

the Malayan Region, in ' Transact, xl. 

Linn. Soc' vol. xxv. 1865, pp. 8, "^ ]\Ir. Bates was so kind as to 

36. A striking case of a rare lay this subject before the Entomo- 

variety, strictly intermediate be- logical Society, and I hare received 

tween two other well-marked female answers to this eftect from several 

varieties, is given by Mr. Wallace, entomologists. 
See also Mr. Bates, in ' Proc. En- 

Chap. XI. Butterflies and Moths. 321 

We are led to this conclusion by cases, even within the same 
genus, of gradation from an extraordinary amount of difference 
to identity in colour between the two sexes. 

But it may be asked whether the differences in colour between 
the sexes may not be accounted for by other means besides 
sexual selection. Thus the males and females of the same 
species of butterfly are in several cases known ^"^ to inhabit 
dilferent 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 tlicy are 
exposed to different conditions during a very short period ; and 
the larvae of both are exposed 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 colours for the 
sake of protection. It seems to me, on the contrary, far more 
probable that it is the males which have been chiefly modified 
through sexual selection, the females having been comparatively 
little changed. We can thus understand how it is that the 
females of allied species generally resemble one another so much 
more closely than do the males. They thus shew us ap- 
proximately the primordial colouring of the parent-species of 
the group to which they belong. They have, however, almost 
always been somewhat modified by the transfer to them of some 
of the successive variations, through the accumulation of which 
the males were rendered beautiful. But I do not wish to deny 
that the females alone of some species may have been specially 
modified for protection. In most cases the males and females of 
distinct species will have been exposed during their prolonged 
larval state to different conditions, and may have been thus 
affected; though with the males any slight change of colour 
thus caused will generally have been masked by the brilliant 
tints gained through sexual selection. When we treat of Birds, 
I shall have to discuss the whole question, as to how far the 
differences in colour between the sexes are due to the males 
having been modified through sexual selection for ornamental 
purposes, or to the females having been modified through 
natural selection for the sake of protection, so that I will here 
say but little on the subject. 

In all the cases in which the more common form of equal 

2« H. W. Bates, 'The Naturalist " Qu this whole subject see 'The 

on the Amazons,' vol. ii. 1863, p. Variation of Animals and Plants 

228. A. R. Wallace, in 'Transact, under Domestication,' 18(J8, vol. ii. 

Linn. Soc' vol. xxv. 1865, p. 10. chap, xxiii. 


322 The Descent of Mmi. Part II. 

inheritance by both sexes has prevailed, the selection of bright- 
coloured males would tend to make the females bright-coloured; 
and the selection of dull-coloured females would tend to make 
the males dull. If both processes were carried on simultaneously, 
they would tend to counteract each other ; and the final result 
would depend on whether a greater number of females from 
being well protected by obscure colours, or a greater number of 
males by l>eing brightly-coloured and thus finding partners, 
succeeded in leaving more numerous oflfspring. 

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 chan.2:ed 
through natural selection into inheritance by one sex alone, but 
in favour of this view I can discover no evidence. We know 
from what occurs under domestication that new characters often 
appear, which from the first are transmitted to one sex alone ; 
and by the selection of such variations there would not be the 
slightest difficulty in giving bright colours to the males alone, 
and at the same time or subsequently, dull colours to the females 
alone. In this manner the females of some butterflies and moths 
have, it is probable, been rendered inconspicuous for the sake of 
protection, and widely different from their males. 

I am, however, unwilling without distinct evidence to admit 
that two complex processes of selection, each requiring the 
transference of new characters to one sex alone, have been 
carried on with a multitude of species, — that the males have 
been rendered more brilliant by beating their rivals, and the 
females more dull-coloured by having escaped from their 
enemies. The male, for instance, of the common brimstone 
butterfly (Gonepteryx), is of a far more intense yellow than the 
female, though she is equally conspicuous ; and it does not seetn 
probable that she specially acquired her pale tints as a protec- 
tion, though it is probable that the male acquired his bright 
colours as a sexual attraction. The female of Anthocharis car- 
damines does not possess the beautiful orange wing-tips of the 
male; consequently she closely resembles the white butterflies 
(Pieris) so common in our gardens ; but we have no evidence 
that this resemblance is beneficial to her. As, on the other hand, 
she resembles both sexes of several other species of the genus 
inhabiting various quarters of the world, it is probable that she 
has simply retained to a large extent her primordial colours. 

Finally, as we have seen, various considerations lead to the 
conclusion that with the greater number of brilliantly-coloured 
Lepidoptera it is the male which has been chiefly modified 
through sexual selection; the amount of difference between 

Chap. XT. Btitterjiies and Moths. 323 

the sexes mostly depending on tlie form of inheritance which 
has prevailed. Inheritance is governed by so many unknown 
laws or conditions, that it seems to us to act in a capricious 
manner ; ^* and we can thus, to a certain extent, understand how 
it is that with closely allied species the sexes either differ to an 
astonishing degree, or are identical in colour. As all the suc- 
cessive steps in the process of variation are necessarily trans- 
mitted through the female, a greater or less number of such 
steps might readily become developed in her; and thus we can 
understand the frequent gradations from an extreme difference 
to none at all between the sexes of allied species. These cases of 
gradation, it may be added, are much too common to favour the 
supposition that we here see females actually undergoing the 
]3rocess of transition and losing their brightness for the sake of 
protection ; for w^e have every reason to conclude that at any 
one time the greater number of speci(;s 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 S, America belonging to quite distinct families, 
resembled the Heliconidse so closely in every stripe and shade of 
colour, that they could not be distinguished save by an ex- 
perienced entomologist. As the Heliconidse are coloured in 
their usual manner, whilst the others depart from the usual 
colouring of the groups to which they belong, it is clear that 
the latter are the imitators, and the Heliconidee the imitated. 
Mr. Bates further observed that the imitating species are com- 
paratively rare, whilst the imitated abound, and that the two 
sets live mingled together. From the fact of the HeliconidsB 
being conspicuous and beautiful insects, yet so numerous in 
individuals and species, he concluded that they must be pro- 
tected from the attacks of enemies by some secretion or odour ; 
and this conclusion has now been amply confirmed,-*' especially 
by Mr. Belt. Hence Mr. Bates inferred that the butterflies 
which imitate the protected species have acquired their present 
marvellously deceptive appearance through variation and natural 
selection, in order to be mistaken for the protected kinds, and 
thus to escape being devoured No explanation is here attempted 
of the brilliant colours of the imitated, but only of the imitating 
butterflies. We must account for the colours of the former in 
the same general manner, as in the cases previously discussed 

"* ' The Variation of Animals and xxiii. 1802, p. 495. 
Plants under Domestication,' vol. ii. ^o < Pyoc. Ent. Soc' Dec. 3rd, 

chap. xii. p. 17. 1866, p. xlv. 

29 ' Transact. Linn. Soc' vol. 

324 The Descent of Man. Part II. 

in this chapter. Since the publication of Mr. Bates' paper, 
similar and equally striking facts have been observed by 
]^[r. Wallace in the Malayan region, by Mr, Trimen in South 
Africa, and by Mr. Eiley in the United States.^^ 

As some writers have felt much difficulty in understanding 
how the first steps in the process of mimicry could have been 
effected through natural selection, it may be well to remark that 
the process probably commenced long ago between forms not 
widely dissimilar in colour. In this case even a slight variation 
would be beneficial, if it rendered the one species more Like 
the other ; and afterwards the imitated species might be modi- 
fied to an extreme degree through sexual selection or other 
means, and if the changes were gradual, the imitators might 
easily be led along the same track, until they differed to an 
equally extreme degree from their original condition ; and they 
would thus ultimately assume an appearance or colouring wholly 
unlike that of the other members of the group to which they 
belonged. It should also be remembered that many species of 
Lepidoptera are liable to considerable and abrupt variations in 
colour. A few instances have been given in this chapter ; and 
many more may be found in the papers of Mr. Bates and 
BIr. Wallace. 

With several species the sexes are alike, and imitate the two 
sexes of another species. But Mr. Trimen gives, in the paper 
already referred to, three cases in which the sexes of the imitated 
form differ from each other in colour, and the sexes of the 
imitating form differ in a like manner. Several cases have also 
been recorded where the females alone imitate brilliantly- 
coloured and protected species, the males retaining "the 
" normal aspect of their immediate congeners." It is here obvious 
that the successive variations by which the female has been 
modified have been transmitted to her alone. It is, however, 
probable that some of the many successive variations would 
have been transmitted to, and developed in, the males had 
not such males been eliminated by being thus rendered less 
attractive to the females; so that only those variations were 
preserved which were from the fii'st strictly limited in their 
transmission to the female sex. We have a partial illus- 
tration of these remarks in a statement by Mr. Belt;='- that 

'^ Wallace, 'Transact. Linn. Soc' 163-168. This latter essay is valu- 

vol. XXV. 1865, p. 1 ; also ' Transact, able, as Mr. Riley here discusses all 

Ent. Soc' vol. iv. (3rd series), 1867, the objections which have been 

p. 301. Trimen, ' Linn. Transact.' raised against Mr. Bates' theory, 

vol. xxvi. 1869, p. 497. Riley, , ^- ' The Naturalist in Nicaragua, 

'Third Annual Report on the Noxi- 1874, p. 385. 
ous Insects of Missouri,' 1871, pp 

OiiAP. Xr. Butterjiies and Moths. 325 

the males of some of the Leptalides, which imitate protected 
species, still retain in a concealed manner some of their original 
characters. Thus in the males ''the npper half of the lower 
" wing is of a pure white, whilst all the rest of the wings is 
" barred and sjDottcd 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 ^^pper wing, 
" so that I cannot imagine its being of any other use to them 
" than as an attraction in courtship, when they exhibit it to the 
" females, and thus gratify their deep-seated preference for the 
" normal colour of the Order to which the Leptalides belong." 

Briijlit Colours of Caterpillars. — Whilst reflecting on the 
beauty of many butterflies, it occurred to me that some cater- 
pillars were splendidly coloured ; and as sexual selection could 
not possibly have here acted, it appeared rash to attribute the 
beauty of the mature insect to this agency, unless the bright 
colours of their larvas could be somehow explained. In the 
first place, it may be observed that the colours of caterpillars do 
not stand in any close correlation with those of the mature 
insect. Secondly, their bright colours do not serve in any 
ordinary manner as a protection. Mr. Bates informs me, as an 
instance of this, that the most conspicuous caterpillar which he 
ever beheld (that of a Sphinx) lived on the large green leaves of 
a tree on the open llanos of South America ; ]t 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 coloured green like the leaves on which they 
" feed, or being curiously like the twigs of the trees on which they 
" live." Another instance of protection, furnished me by Mr, J. 
Mansel Weale, may be added, namely, that there is a caterpillar 
of a moth which lives on the mimosas in South Africa, and 
fabricates for itself a case quite indistinguishable from the 
surrounding thorns. From such considerations Mr. Wallace 
thought it probable that conspicuously-coloured oateri^illars 
were protected by having a nauseous taste ; but as their skin 
is extremely tender, and as their intestines readily protrude 
from a wound, a slight peck from the beak of a bird would 
be as fatal to them as if they had been devoured. Hence, as 

326 The Descent of Man. Paet II 

Mr. Wallace remarks, " distastefulness alone would be insufficient 
" to protect a caterpillar unless some outward sign indicated to 
" its would-be destroyer that its prey was a disgusting morsel." 
Under these circumstances it would be highly advantageous to 
a caterpillar to be instantaneously and certainly recognised as 
unpalatable by all birds and other animals. Thus the most 
gaudy colours would be serviceable, and might have been 
gained by variation and the sui'vival of the most easily-re- 
cognised individuals. 

This hypothesis appears at first sight very bold, but when it 
was brought before the Entomological Society ^^ it was supported 
by various statements ; and Mr. J. Jenner Weir, who keeps a 
large number of birds in an aviary, informs me that he has 
made many trials, and finds no exception to the rule, that all 
caterpillars of nocturnal and retiring habits with smooth skins, 
all of a green colour, and all which imitate twigs, are greedily 
devoured by his birds. The hairy and spinose kinds are 
in variably rejected, as were four conspicuously-coloured species. 
When the birds rejected a caterpillar, they plainly shewed, by 
shaking their heads, and cleansing their beaks, that they were 
disgusted by the taste.^ Three conspicuous kinds of cater- 
pillars and moths were also given to some lizards and frogs, by 
Mr. A. Butler, and were rejected, though other kinds were 
eagerly eaten. Thus the probability of Mr. Wallace's view is 
confirmed, namely, that certain caterpillars have been made 
conspicuous for their own good, so as to be easily recognised by 
their enemies, on nearly the same principle that poisons are sold 
in coloured bottles by druggists for the good of man. We 
cannot, however, at present thus explain the elegant diversity 
in the colours of many caterpillars ; but any species which had 
at some former period acquired a dull, mottled, or strijDed appear- 
ance, either in imitation of surrounding objects, or from the 
direct action of climate, &c., almost certainly would not become 
uniform in colour, when its tints were rendered intense and 
bright ; for in order to make a caterpillar merely conspicuous, 
there would be no selection in any definite direction. 

Summary and Concluding Bemarhs on Insects. — Looking back 

23 * Proc. Entomolog. Soc* Dec. analogous facts in the ' Third An- 

3rd, 1866, p. xlv., and March 4th, nual Report on the Noxious Insects 

1867, p. Ixxx. of Missouri,' 1871, p. 148. Some 

^'^ See Mr. J. Jenner Weir's opposed cases are, however, given hy 

paper on Insects and Insectivorous Dr. Wallace and M, H. d'Orville ; 

Birds, in ' Transact. Ent. Soc' 1869, see 'Zoological Record,' 1869, p. 

p. 21 ; also Mr. Butler's paper, 349. 
ibid. p. 27. Mr. Riley has given 

Chap. XI. Stivimary on Insects. 327 

to the several Orders, we see that the sexes often differ in 
various characters, the meaning of which is not in the least 
understood. The sexes, also, often differ in their organs of 
sense and means of locomotion, so that the males may quickly 
discover and reach the females. They differ still oftener in 
the males possessing diversified contrivances for retaining the 
females when found. We are, however, here concerned only in 
a secondary degree with sexual differences of these kinds. 

In almost all the Orders, the males of some species, even of 
weak and delicate kinds, are known to be highly pugnacious ; 
and some few are furnished with special weapons for fighting 
with their rivals. But the law of battle does not prevail nearly 
so widely with insects as with the higher animals. Hence it 
probably arises, that it is in only a few cases that the males have 
been rendered larger and stronger than the females. On the 
contrary, they are usually smaller, so that they may be developed 
within a shorter time, to be ready in large numbers for the 
emergence of the females. 

In two families of the Homoptera and in three of the Orthop- 
tera, the males alone possess sound-producing organs in an 
efficient state. These are used incessantly during the breeding- 
season, not only for calling the females, but apparently for 
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 these musical instru- 
ments have been acquired through sexual selection. In four 
other Orders the members of one sex, or more commonly of 
both sexes, are provided with organs for producing various 
sounds, which apparently serve merely as call-notes. When 
both sexes are thus provided, the individuals which were able 
to make the loudest or most continuous noise would gain 
partners before those which were less noisy, so that their organs 
have probably been gained through sexual selection. It is 
instructive to reflect on the wonderful diversity of the means 
for producing sound, possessed by the males alone, or by both 
sexes, in no less than six Orders. We thus learn how effectual 
sexual selection has been in leading to modifications which 
sometimes, as with the Homoptera, relate to important parts of 
the organisation. 

From the reasons assigned in the last chapter, it is probable 
that the great horns possessed by the males of many Lamel- 
licorn, and some other beetles, have been acquired as ornaments. 
From the small size of insects, we are apt to undervalue their 
appearance. If we could imagine a male Chalcosoma (fig. 16), 
with its polished bronzed coat of mail, and its vast complex 

328 The Descent of Man. Paet II. 

horns, magnified to the size of a horse, or even of a dog, it would 
be one of the most imposing animals in the world. 

The colouring of insects is a complex and obscure subject. 
When the male differs slightly from the female, and neither are 
briUiantly-coloured, it is probable that the sexes have varied 
in a slightly different manner, and that the variations have been 
transmitted by each sex to the same, without any benefit or 
evil thus accruing. When the male is brilliantly-coloured and 
difi"ers conspicuously from the female, as with some dragon-flies 
and many butterflies, it is probable that he owes his colours to 
sexual selection ; whilst the female has retained a primordial or 
very ancient type of colouring, slightly modified by the agencies 
before explained. But in some cases the female has a^Dparently 
been made obscure by variations transmitted to her alone, 
as a means of direct protection ; and it is almost certain that 
she has sometimes been made brilliant, so as to imitate other 
protected species inhabiting the same district. When the sexes 
resemble each other and both are obscurely coloured, there is 
no doubt that they have been in a multitude of cases so coloured 
for the sake of protection. So it is in some instances when both 
are brightly-coloured, for they thus imitate protected species, or 
resemble surrounding objects such as flowers; or they give 
notice to their enemies that they are unpalatable. In other 
cases in which the sexes resemble each other and are both 
brilliant, especially when the colours are arranged for display, 
we may conclude that they have been gained by the male sex as 
an attraction, and have been transferred to the female. We are 
more especially led to this conclusion whenever the same typo 
of coloration* prevails throughout a whole group, and we find 
that the males of some species difier widely in colour from 
the females, whilst others differ slightly or not at all, with 
intermediate gradations connecting these extreme states. 

In the same manner as bright colours have often been 
partially transferred from the males to the females, so it has 
been with the extraordinary horns of many Lamellicorn and 
some other beetles. So again, the sound-producing organs 
proper to the males of the Homoptera and Orthoptera have 
generally been transferred in a rudimentary, or even in a nearly 
perfect condition, to the females; yet not sufficiently perfect to 
be of any use. It is also an interesting fact, as bearing on 
sexual selection, that the stridulating organs of certain male 
Orthoptera are not fully developed until the last moult; and that 
the colours of certain male dragon-flies are not fully develoi^ed 
until some little time after their emergence from the pupal 
state, and when they are ready to breed. 

Chap. XI. Summary on Insects. 329 

Sexual selection implies that the more attractive individuals 
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 the type to 
which the species belongs ; — and as it is the male which searches 
eagerly for the female, we must suppose that the females 
habitually or occasionally prefer the more beautiful males, and 
that these have thus acquired their beauty. That the females 
in most or all the orders would have the power of rejecting 
any particular male, is probable from the many singular con- 
trivances possessed by the males, such as great jaws, adhesive 
cushions, spines, elongated legs, &c., for seizing the female ; for 
these contrivances shew that there is some difficulty in the act, 
so that her concurrence would seem necessary. Judging from 
what we know of the perceptive powers and affections of 
various insects, there is no antecedent improbability in sexual 
selection having come largely into play ; but we have as yet no 
direct evidence on this head, and some facts are opposed to the 
belief. Nevertheless, when we see many males pursuing the 
same female, we can hardly believe that the pairing is left to 
blind chance — that the female exerts no choice, and is not 
influenced by the gorgeous colours or other ornaments with 
which the male is decorated. 

If we admit that the females of the Homoptera and Orthoptera 
appreciate the musical tones of their male partners, and that the 
various instruments have been perfected through sexual se- 
lection, there is little improbability in the females of other 
insects appreciating beauty in form or colour, and consequently 
in such characters having been thus gained by the males. But 
from the circumstance of colour being so variable, and from its 
having been so often modified for the sake of protection, it is 
difficult to decide in how large a jn-oportion of cases sexual 
selection has played a part. This is more especially difficult in 
those Orders, such as Orthoptera, HymenoiDtera, and Coleop- 
tera, in which the two sexes rarely differ much in colour ; for 
we are then left to mere analogy. With the Coleoptera, however, 
as before remarked, it is in the great Lamellicorn group, placed 
by some authors at the head of the Order, and in which we 
sometimes see a mutual attachment between the sexes, that 
we find the males of some species possessing weapons for sexual 
strife, others furnished with wonderful horns, many with stridu- 
lating organs, and others ornamented with splendid metallic 
tints. Hence it seems probable that all these characters have 
been gained through the same means, namely sexual selection. 
With butterflies we have the best evidence, as the males 

330 The Descent of Man. Paet II. 

sometimes take pains to display their beautiful colours; and we 
cannot believe that they would act thus, unless the display was 
of use to them in their courtship. 

When we treat of Birds, we shall see that they present in 
their secondary sexual characters the closest analogy with 
insects. Thus, many male birds are highly pugnacious, and 
some are furnished with special weapons for fighting with their 
rivals. They possess organs which are used dui'ing the breeding- 
season for producing vocal and instrumental music. They are 
frequently ornamented with combs, horns, wattles and plumes 
of the most diversified kinds, and are decorated with beautiful 
colours, all evidently for the sake of display. "We shall find 
that, as with insects, both sexes in certain groups are equally 
beautiful, and are equally provided with ornaments which are 
usually confined to the male sex. In other groups both sexes 
are equally plain-coloured and unornamented. Lastly, in some 
few anomalous cases, the females are more beautiful than the 
males. We shall often find, in the same group of birds, every 
gradation from no diff"erence 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. W^hatever explanation applies to the 
one class probably applies to the other ; and this explanation, 
as we shall hereafter attempt to shew in fui'ther detail, is sexual 


Secondary Sexual Characters of Fishes, Amphibians, 
AND Reptiles. 

Fishes: Courtship and battles of the males — Larger size of the females 
— Males, bright colours and ornamental appendages; other strange 
characters — Colours and appendages acquired by the males during the 
breeding-season alone — Fishes with both sexes brilliantly coloured 
— Protective colours — The less conspicuous colours of the female cannot 
be accounted for on the principle of protection — Male tishes building 
nests, and taking charge of the ova and young. Ajniphibians : Dif- 
ferences in structure and colour between the sexes — Vocal organs. 
Reptiles : Chelonians — Crocodiles — Snakes, colours in some cases pro- 
tective — Lizards, battles of — Ornamental appendages — Strange dif- 
ferences in structure between the sexes — Colours — Sexual differences 
almost as great as with birds. 

We have now arrived at the great sub-kingdom of the Vertebrata, 
and will commence with the lowest class, that of Fishes. The 

Chap. XII. Fishes. 33 1 

males of Plagiostomous fishes (sharks, rays) and of Chimaeroid 
fislies are provided with claspers which serve to retain the 
female, like the various structures possessed by many of the 
lower animals. Besides the claspers, the males of many rays 
have clusters of strong sharp spines on their heads, and several 
rows along " the upper outer surface of their pectoral fins." 
These are present in the males of some species, which have 
other parts of their bodies smooth. They are only temporarily 
developed during the breeding-season ; and Dr. GUnther suspects 
that they are brought into action as prehensile organs by the 
doubling inwards and downwards of the two sides of the body. 
It is a remarkable fact that the females and not the males of 
some species, as of Ilaia davata, have their backs studded with 
large hook-formed spines.^ 

The males alone of the capehn {Mallotus villosus, one of 
Salmonidse), are provided with a ridge of closely-set, brush-like 
scales, by the aid of which two males, one on each side, hold the 
female, whilst she runs with great swiftness on the sandy beach, 
and there deposits her si3awn.^ The widely distinct Monaccmthus 
scopas presents a somewhat analogous structure. The male, as 
Dr. GiJnther informs me, has a cluster of stiff, straight spines, 
like those of a comb, on the sides of the tail ; and these in a 
specimen six inches long were nearly one and a half inches in 
length ; the female has in the same place a cluster of bristles, 
which may be compared with those of a tooth-brush. In 
another species, M. peronii, the male has a brush like that 
possessed by the female of the last species, whilst the sides of 
the tail in the female are smooth. In some other species of the 
same genus the tail can be perceived to be a little roughened in 
the male and perfectly smooth in the female; and lastly in 
others, both sexes have smooth sides. 

The males of many fish fight for the possession of the females. 
Thus the male stickleback (Gasterosfeus leiurus) has been de- 
scribed as " mad with delight," when the female comes out of her 
hiding-place and surveys the nest which he has made for her. 
*' He darts round her in every direction, then to his accumulated 
*' materials for the nest, then back again in an instant ; and as 
" she does not advance he endeavours to push her with his snout, 
" and then tries to pull her by the tail and side- spine to the nest."^ 

» Yarrell's 'Hist, of British 1871, p. 119. 

Fishes,' vol. ii. 1836, pp. 417, 425, 3 See Mr. R. Waringtoii's in- 

436. Dr. Giinther informs me that terestiug articles in ' Annals and 

the spines in R. clacata are peculiar Mag. of Nat. Hist.' Oct. 1852 and 

to the female. Nov. 1855. 

- * The American Naturalist,' April 

332 The Descent of Man. Part II. 

The males are said to be polygamists ;^ they are extraordinarily 
bold and pugnacious, whilst " the females are quite pacific." 
Their battles are at times desperate ; ''for these puny com- 
" batants fasten tight on each other for several seconds, tumbling 
" over and over again, until their strength appears completely 
" exhausted." With the rough-tailed stickleback (G^. trachurus) 
the males whilst fighting swim round and round each other, 
biting and endeavouring to pierce each other with their raised 
lateral spines. The same writer adds,^ " the bite of these little 
" furies is very severe. They also use their lateral spines with 
" such fatal efiect, that I have seen one during a battle absolutely 
" rip his opponent quite open, so that he sank to the bottom and 
" died." When a fish is conquered, " his gallant bearing forsakes 
" him ; his gay colours fade away ; and he hides his disgrace 
"among his peaceable companions, but is for some time the 
" constant object of his conqueror's persecution." 

The male salmon is as pugnacious as the little stickleback ; 
and so is the male trout, as I hear from Dr. Giinther. Mr. Shaw 
saw a violent contest between two male salmon which lasted 
the whole day ; and Mr. R. Buist, Sui3erintendent of Fisheries, 
informs me that he has often watched from the bridge at Perth 
the males driving away their rivals, whilst the females were 
spawning. The males " are constantly fighting and tearing each 
" other on the spawning-beds, and many so injure each other as 
" to cause the death of numbers, many being seen swimming near 
" the banks of the river in a state of exhaustion, and apparently 
" in a dying state."^ Mr. Buist informs me, that in June 1868, 
the keeper of the Stormontfield breeding-ponds visited the 
northern Tyne and found about 300 dead salmon, all of which 
with one exception wei-e males ; and he was convinced that they 
had lost their lives by fighting. 

The most curious point about the male salmon is that during 
the breeding-season, besides a slight change in colour, " the 
" lower jaw elongates, and a cartilaginous projection turns 
" upwards from the point, which, when the jaws are closed, 
" occupies a deep cavity between the intermaxillary bones of the 
upper jaw." '^ (Figs. 27 and 28.) In our salmon this change of 
structure lasts only during the breeding-season; but in the 

■* Xoel Humphreys, 'River Gar- experienced observer (Scrope's * Days 

dens,' 1857. of Salmon Fishing/ p. 60) remarks 

^ Loudon's ' Mag. of Nat. History,' that lilie the stag, the male would, 

vol. iii. 1830, p. 331. if he could, keep all other males 

« 'The Field,' June 29th, 18G7. away. 
For Mr. Shaw's statement, see ^ Yarrell, ' History of British 

'Edinburgh Review,' 1843. Another Fishes,' vol. ii. 1836, p. 10. 

Ceap. XIL 



Salmo hjcabdon of N.-W. America the change, as Mr. J. K. Lord^ 
believes, is permanent, and best marked in the older males which 
have previously ascended the rivers. In these old males the 
jaw becomes developed into an immense hook-like projection, and 

Fig. 27. Head of male common salmon (Salmo salar) during the breeding-season. 

TThis drawing, as well as all the others in the present chaptnr, have been executed 
by the well-known artist, Mr. G. Ford, from specimens in the British Museum, under 
the kind superintendence of Dr. Gtinther.J 

the teeth grow into regular fangs, often more than half an inch 
in length. With the European salmon, according to Uv. Lloyd,^ 
the temporary hook-like structure serves to strengthen and 

* 'The Naturalist in Vancouver's ^ 'Scandinavian Adventures,' vol 

Island,' vol. i. 1866, p. 54. i. 1854, pp. 100, 104. 


The Descent of Man, 


protect the jaws, when one male charges another with wonderful 
violence ; but the greatly developed teeth of the male American 
salmon may be compared with the tusks of many male mammals, 
and they indicate an oifensive rather than a jDrotectivc purpose. 

Fig 28 

Head of female salmon. 

The salmon is not the only fish in which the teeth differ in 
the two sexes ; as this is the case with many rays. In the 
thornback (^Eam davatci) the adult male has sharp, pointed 
teeth, directed backwards, whilst those of the female are broad 
and flat, and form a pavement ; so that tbese teeth differ in the 
two sexes of the same species more than is usual in distinct 
genera of the same family. The teeth of the male become sharp 
only when he is adult : whilst young they are broad and fiat 

Cu AP. X 1 1. Fishes. 335 

like those of the female. As so frequently occurs with secondary 
sexual characters, both sexes of some species of rays (for instance 
R. hatis), when adult, possess sharjD pointed teeth ; and here a 
character, proper to and primarily gained by the male, appears 
to have been transmitted to the offspring of both sexes. The 
teeth are likewise pointed in both sexes of 11. maculata, but only 
when quite adult ; the males acquiring them at an earlier age 
than the females. We shall hereafter meet with analogous 
cases in certain birds, in which the male acquires the plumage 
common to both sexes when adult, at a somewhat earlier age than 
does the female. With other species of rays the males even when 
old never possess sharp teeth, and consequently the adults of both 
sexes are provided with broad, flat teeth like those of the young, 
and like those of the mature females of the above-mentioned 
species.^^ As the rays are bold, strong and voracious fish, wo 
may suspect that the males require their sharp teeth for fighting 
with their rivals ; but as they possess many parts modified and 
adapted for the prehension of the female, it is possible that their 
teeth may be used for this purpose. 

In regard to size, M. Carbonnier " maintains that the female of 
almost all fishes is larger than the male ; and Dr. Giinther does 
not know of a single instance in which the male is actually 
larger than the female. With some Cyprinodonts the male is 
not even half as large. As in many kinds of fishes the males 
habitually fight together, it is surprising that they have not 
generally become larger and stronger than the females through 
the effects of sexual selection. The males suffer from their 
small size, for according to M. Carbonnier, they are liable to be 
devoured by the females of their own species when carnivorous, 
and no doubt by other species. Increased size must be in some 
manner of more importance to the females, than strength and 
size are to the males for fighting with other males; and this 
perhaps is to allow of the production of a vast number of ova. 

In many species the male alone is ornamented with bright 
colours; or these are much brighter in the male than the 
female. The male, also, is sometimes provided with appendages 
which appear to be of no more use to him for the ordinary 
purposes of life, than are the tail feathers to the peacock. I am 
indebted for most of the following facts to the kindness of Dr. 
Giinther. There is reason to suspect that many tropical fishes 
differ sexually in colour and structure ; and there are some 
striking cases with our British fishes. The male Calliojiymns lyra 

^•^ See Yarrell's account of the cellent figure, and p. 422, 432. 
rays in his ' Hist, of British Fishes,' ^^ As quoted in 'The Fanner, 

vol. ii. 1836, p. 410, with an ex- 1868, p. 369. 


The Descent of Man. 

Part II. 

has been called the gemmeoiis dragonet " from its brilliant gem- 
" like colours/' When fresh caught from the sea the body is 
yellow of various shades, striped and spotted with vivid blue on 
the head ; the dorsal fins are pale brown with dark longitudinal 
bands; the ventral, caudal, and anal fins being bluish-black. 
The female, or sordid dragonet, was considered by Linnseus, and 
by many subsequent naturalists, as a distinct species ; it is of a 
dingy reddish-brown, with the dorsal fin brown and the other 

Fig. 29. Callionymus lyra. Upper figure, male ; lower figure, female. 
N.B. The lower figure is more reduced than the upper. 

fins white. The sexes differ also in the proportional size of the 
head and mouth, and in the position of the eyes ;^^ but the 
most striking difference is the extraordinary elongation in the 
male (fig. 29) of the dorsal fin. I\Ir. W. SaviUe Kent remarks 
that this " singular appendage appears from my observations 
" of the species in confinement, to be subservient to the same 
" end as the wattles, crests, and other abnormal adjuncts of 
" the male in gallinaceous birds, for the jDurpose of fascinating 

'- I have drawn up this description from Yarrell's ' British Fishes,'voI. 1. 
1836, pp. 261 and 2(36. 

Chap. XII. 



** their mates." ^^ The young males resemble the adult females 
in structure and colour. Throughout the genus Callionymus/* 
the male is generally much more brightly spotted than the 
female, and in several species, not only the dorsal, but the anal 
fin is much elongated in the males. 

The male of the Coitm scorpius, or sea-scorpion, is slenderer 
and smaller than the female. There is also a great difference 
in colour between them. It is difficult, as Mr. Lloyd ^^ remarks, 
" for any one, who has not seen this fish during the spawning- 
" season, when its hues are brightest, to conceive the admixture 
" of brilliaut colours with which it, in other respects so ill- 
*' favoured, is at that time adorned." Both sexes of the Lahrus 
mixtiis, although very diiferent in colour, are beautiful; the 
male being oraoge with bright blue stripes, and the female 
bright red with some black spots on the back. 

Fig. 30. Xiphophorus Hellerii. Upper figure, male ; lower figure, female. 

In the very distinci; family of the Cyprinodoutidse— inhabitants 
of the fresh waters of foreign lands— the sexes sometimes differ 
much in various characters. In the male of the MolUeuesia 
petenensis,'^^ the dorsal fin is greatly developed and is marked 

'6 With respect to this and the 
following; species I am indebted to 
Dr. Giinther for information: see 

'3 'Nature,' July 1873, p. 264. 

** ' Catalogue of Acanth. Fishes 
in the British Museum,' by Dr. 
Giinther, 1861, pp. 138-151. 

^^ * Game Birds of Sweden,' &c.. 
1867, p. 466. 

also his paper on the 'Fishes of 
Central America,' in 'Transact. 
Zoolog. Soc' vol. y\. 1868, p. 485. 

338 The Descent of Man. - Part IT. 

with a row of large, round, ocellated, bright-coloured spots; 
whilst the same fin in the female is smaller, of a different shape, 
and marked only with irregularly curved brown spots. In the 
male the basal margin of the anal fin is also a little produced 
and dark coloured. In the male of an allied form, the Xipho- 
phorns Helhrli (fig. 30), the inferior margin of the caudal fin is 
developed into a long filament, which, as I hear from Dr. Giinther, 
is striped with bright colours. This filament does not contain 
any muscles, and apparently cannot be of any direct use to the 
fish. As in the case of the Callionymus, the males whilst young 
resemble the adult females in colour and structure. Sexual 
differences such as these may be strictly compared with those 
which are so frequent with gallinaceous birds.^''' 

In a siluroid fish, inhabiting the fresh waters of South America, 
the Plecostomus harbatus^^ (fig. 31), the male has its mouth and 
inter-operculum fringed with a beard of stiff hairs, of which the 
female shows hardly a trace. These hairs are of the nature of 
scales. In another species of the same genus, soft flexible ten- 
tacles project from the front part of the head of the male, which 
are absent in the female. These tentacles are prolongations of 
the true skin, and therefore are not homologous with the stiff 
hairs of the former species ; but it can hardly be doubted that 
both serve the same purpose. What this purpose may be, it is 
difficult to conjecture ; ornament does not here seem probable, 
but we can hardly suppose that stiff hairs and flexible filaments 
can be useful in any ordinary way to the males alone. In that 
strange monster, the Chimcera monsfrom, the male has a hook- 
shaped bone on the top of the head, directed forwards, with its 
end rounded and covered with sharp spines ; in the female " this 
" crown is altogether absent," but what its use may be to the 
male is utterly unknown.^'' 

The structures as yet referred to are permanent in the male 
after he has arrived at maturity ; but with some Blennies, and in 
another aUied genus,^° a crest is developed on the head of the 
male only during the breeding-season, and the body at the same 
time becomes more brightly-coloured. There can be little doubt 
that this crest serves as a temporary sexunl ornament, for the 
female does not exhibit a trace of it. In other species of the 
same genus both sexes possess a crest, and in at least one s^Decies 

'^ Dr. Giinther makes this re- Water,' July 1368, p. 377, with a 

mark; * Catalogue of Fishes in the figure. Many other cases could be 

British Museum,' vol. iii. 1861, p. added of structures peculiar to the 

141. male, of which the uses are not 

^* See Dr. Giinther on this genus, known, 

m 'Proc. Zoolog. Soc' 1868, p. 232. =» Dr. Giinther, ' Catalogue of 

l^ F. Buckland, in * Land and Fishes,' vol. iii. pp. 221 and 240. 

Chap. XII. 



Fig. 31. Plecostomus barbatus. L i-p-n i.b"' 

..3 ; lower figure, female. 

340 The Descent of Man. Part II. 

neither sex is thus provided. In many of the Chromidse, for 
instance in Geophagus and especially in Cichla, the males, as I 
hear from Professor Agassiz/^ have a conspicuous protuberance 
on the forehead, which is wholly wanting in the females and in 
the young males. Professor Agassiz adds, " I have often 
" observed these fishes at the time of spawning when the ;pro- 
" tuberance is largest, and at other seasons when it is totally 
*' wanting, and the two sexes shew no difference whatever in the 
" outline of the profile of the head.- I never could ascertain that 
" it subserves any special function, and the Indians on the 
" Amazon know nothing about its use." These protuberances 
resemble, in their periodical appearance, the fleshy caruncles on 
the heads of certain birds ; but whether they serve as ornaments 
must remain at present doubtful. 

I hear from Professor Agassiz and Dr. Giinther, that the males 
of those fishes, which differ permanently in colour from the 
females, often become more brilliant during the breeding-season. 
This is likewise the case with a multitude of fishes, the sexes of 
which are identical in colour at all other seasons of the year, 
The tench, roach, and perch may be given as instances. The 
male salmon at this season is "marked on the cheeks with 
*'■ orange-coloured stripes, which give it the ajDpearance of a 
** Labrus, and the body partakes of a golden orange tinge. The 
" females are dark in colour, and are commonly called black- 
'*'fish."2^ An analogous and even greater change takes place 
with the Salmo eriox or bull trout ; the males of the char 
(iS. umhla) are likewise at this season rather brighter in colour 
than the females.^^ The colours of the pike (Esox reticulatus) of 
the United States, especially of the male, become, during the 
breeding-season, exceedingly intense, brilliant, and iridescent.'^* 
Another striking instance out of many is afforded by the male 
stickleback (Gasferosteus leiurus), which is described by Mr. 
Warington,^^ as being then "beautiful beyond description." 
The back and eyes of the female are simply brown, and the belly 
white. The eyes of the male, on the other hand, are " of the 
" most splendid green, having a metallic lustre like the green 
" feathers of some humming-birds. The throat and belly are 
" of a bright crimson, the back of an ashy-green, and the whole 
" fish appears as though it were somewhat translucent and 

2' See also * A Journey in Brazil,' Mag. of Nat. History,' vol. vi. 1841, 

by Prof, and Mrs. Agassiz, 1868, p. p. 440. 
220. 24 'The American Agriculturalist,' 

" Yarrell, * British Fishes,' vol. 1868, p. 100. 
ii. 1836, pp. 10, 12, 35. 25 . Annals and Mag. of Nat. Hist.' 

2^ W. Thompson, in 'Annals and Oct. 1852. 

Chap. XII. Fishes. 341 

" glowed with an internal incandescence." After the breeding- 
season these colours all change, the throat and belly become of a 
paler red, the back more green, and the glowing tints subside. 

With respect to the courtship of fishes, other cases have been 
observed since the first edition of this book appeared, besides that 
already given of the stickleback. Mr. W. S. Kent says that the 
male of the Lalwus mixtns, which, as we have seen, differs in 
colour from the female, makes " a deep hollow in the sand of the 
" tank, and then endeavours in the most persuasive manner to in- 
" duce a female of the same species to share it with him, swim- 
" ming backwards and forwards between her and the completed 
'' nest, and x^lainly exhibiting the greatest anxiety for her to follow." 
The males of Cantharus lineatus become, during the breeding- 
season, of deep leaden-black ; they then retire from the shoal, and 
excavate a hollow as a nest. "Each male now mounts vigilant 
" guard over his respective hollow, and vigorously attacks and 
*• drives away any other fish of the same sex. Towards his com- 
" panions of the opposite sex his conduct is far different ; many of 
" the latter are now distended with spawn, and these he endeavours 
" by all the meaus in his power to lure singly to his prepared 
" hollow, and there to deposit the myriad ova with which they are 
" laden, which he then protects and guards with the greatest care.^" 

A more striking case of courtship, as well as of display, by the 
males of a Chinese Macropus has been given by M. Carbonnier, 
who carefully observed these fishes under confinement.-^ The 
males are most beautifully coloured, more so than the females. 
During the breeding-season they contend for the possession of 
the females; and, in the act of courtship, expand their fins, 
which are spotted and ornamented with brightly coloured rays, 
in the same manner, according to M. Carbonnier, as the peacock. 
They then also bound about the females with much vivacity, and 
appear by " I'etalage de leurs vives couleurs chercher a attirer 
" I'attention des femelles, lesquelles ne paraissaient indifferentes 
" a ce manege, elles nageaient avec une molle lenteur vers les 
" males et semblaient se comjDlaire dans leur voisinage." After 
the male has won his bride, he makes a little disc of froth by 
blowing air and mucus out of his mouth. He then collects the 
fertilised ova, drojDped by the female, in his mouth ; and this 
caused M. Carbonnier much alarm, as he thought that they were 
going to be devoured. But the male soon deposits them in the 
disc of froth, afterwards guarding them, repairing the froth, and 
taking care of the young when hatched. I mention these par- 
ticulars because, as we shall presently see, there are fishes, the 

26 < Nature,' May, 1873, p. 25. 27 .Bull, de la Soc. d'Acclimat.' 

Paris, July 1869, and Jan. 1870. 

342 The Descent of Man. Part II. 

males of whicli hatch their eggs in their mouths ; and those who 
do not believe in the principle of gradual evolution might ask how 
could such a habit have originated ; but the diflficulty is much 
diminished when we know that there are fishes which thus 
collect and carry the eggs; for if delayed by any cause in 
depositing them, the habit of hatching them in their mouths 
might have been acquired. 

To return to our more immediate subject. The case stands 
thus : female fishes, as far as I can learn, never willingly spawn 
except in the presence of the males ; and the males never fertilise 
the ova except in the presence of the females. The males fight 
for the possession of the females. In many species, the males 
whilst young resemble the females in colour ; but when adult 
become much more brilliant, and retain their colours throughout 
life. In other species the males become brighter than the females 
and otherwise more highly ornamented, only during the season 
of love. The males sedulously court the females, and in one 
case, as we have seen, take pains in displaying their beauty 
before them. Can it be believed that thej would thus act to no 
purpose during their courtship ? And this would be the case, 
unless the females exert some choice and select those males 
which please or excite them most. If the female exerts such 
choice, all the above facts on the ornamentation of the males 
become at once intelligible by the aid of sexual selection. 

We have next to enquire whether this view of the bright 
colours of certain male fishes having been acquired through 
sexual selection can, through the law of the equal transmission of 
characters to both sexes, be extended to those groups in which the 
males and females are brilliant in the same, or nearly the same 
degree and manner. In such a genus as Labrus, which includes 
some of the most splendid fishes in the world — for instance, the 
Peacock Labrus {L. -pavo), described,-^ with pardonable exaggera- 
tion, as formed of polished scales of gold, encrusting lajDis-lazuli, 
rubies, sapphires, emeralds, and amethysts — we may, with much 
probability, accept this belief; for we have seen that the sexes in 
at least one species of the genus differ greatly in colour. With 
some fishes, as with many of the lowest animals, splendid colours 
may be the direct result of the nature of their tissues and of the 
surrounding conditions, without the aid of selection of any kind. 
The gold-fish {Cyprinus auratus), judging from the analogy of 
the golden variety of the common carp, is perhaps a case in point, 
as it may owe its splendid colours to a single abrupt variation, 
due to the conditions to which this fish has been subjected under 

28 Bory de Saint Vincent, in 'Diet. Class. d'Hist. Nat.' torn. ix. 1826 
p. 151. 

Chap. XII. Fishes. 343 

confinement. It is, however, more probable that these colours 
have been intensified through artificial selection, as this species 
has been carefully bred in China from a remote period.^^ Under 
natural conditions it does not seem probable that beings so 
highly organised as fishes, and which live under such complex 
relations, should become brilliantly coloured without suffering 
some evil or receiving some benefit from so great a change, and 
consequently without the intervention of natural selection. 

What, then, are we to conclude in regard to the many fishes, 
both sexes of which are splendidly coloured? Mr. Wallace ^'^ 
believes that the species which frequent reefs, where corals and 
other brightly-coloured organisms abound, are brightly coloured 
in order to escape detection by their enemies ; but according to 
my recollection they were thus rendered highly conspicuous. 
In the fresh-waters of the tropics there are no brilliantly- 
coloured corals or other organisms for the fishes to resemble ; 
yet many species in the Amazons are beautifully coloured, and 
many of the carnivorous Cyprinidse in India are ornamented 
with "bright longitudinal lines of various tints." ^^ Mr. M'Clel- 
land, in describing these fishes, goes so far as to suppose that 
" the peculiar brilliancy of their colours " serves as " a better 
" mark for king-fishers, terns, and other birds which are 
" destined to keep the number of these fishes in check ; " but at 
the present day few naturalists will admit that any animal has 
been made conspicuous as an aid to its own destruction. It is 
possible that certain fishes may have been rendered conspicuous 
in order to warn birds and beasts of prey that they were 
unpalatable, as explained when treating of caterpillars; but it 
is not, I believe, known that any fish, at least any fresh-water 
fish, is rejected from being distasteful to fish-devouring animals. 
On the whole, the most probable view in regard to the fishes, of 
which both sexes are brilliantly coloured, is that their colours 
were acquired by the males as a sexual ornament, and were 
transferred equally, or nearly so, to the other sex. 

"^ Owing to some remai*ks on this has been " produced at Hangchow a 

subject, made in my work ' On the " variety called the fire-fish, from its 

Variation of Animals under Domesti- "intensely red colour. It is uni- 

cation,' Mr. W. F. Mayers (' Chinese " versally admired, and there is not 

Notes and Queries,' Aug. 1868, p. " a household where it is not cul- 

123) has searched the ancient " tivated, w rivalry as to its colour, 

(.•hinese encyclopedias. He finds " and as a source of profit." 

that gold-fish were first reared iu ^^ * Westminster Review,' July 

confinement during the Sung Dy- 1867, p. 7. 

nasty, which commenced A.D. 960. ^i < Judian Cyprinidaj,' by Mr. J, 

In the year 1129 these fishes M'Clelland, 'Asiatic Researches, 

abounded. In another place it is vol. xix. part ii. 1839, p. 230. 
said that since the year 1548 there 

344 The Descent of Ma7L Part II. 

We have now to consider wliether, when the male differs in a 
marked manner from the female in colour or in other orna- 
ments, he alone has been modified, the variations being inherited 
by his male offspring alone; or whether the female has been 
specially modified and rendered inconspicuous for the sake of 
jn-otection, such modifications being inherited only by the 
females. It is impossible to doubt that colour has been gained 
by many fishes as a protection : no one can examine the speckled 
upper surface of a flounder, and overlook its resemblance to the 
sandy bed of the sea on which it lives. Certain fishes, moreover, 
can through the action of the nervous system, change their 
colours in adaptation to surrounding objects, and that within a 
short time.^^ One of the most striking instances ever recorded 
of an animal being protected by its colour (as far as it can be 
judged of in preserved specimens), as well as by its form, is that 
given by Dr. Giinther^^ of a pipe-fish, which, with its reddish 
streaming filaments, is hardly distinguishable from the sea-weed 
to which it clings with its prehensile tail. But the question now 
imder consideration is whether the females alone have been 
modified for this object. We can see that one sex will not be 
modified through natural selection for the sake of protection 
more than the other, supposing both to vary, unless one sex is 
exposed for a longer period to danger, or has less power of 
escaping from such danger than the other; and it does not 
appear that with fishes the sexes differ in these respects. As 
far as there is any difference, the males, from being generally 
smaller and from wandering more about, are exposed to greater 
danger than the females; and yet, when the sexes differ, the 
males are almost always the more conspicuously coloured. 
The ova are fertilised immediately after being deposited ; and 
when this process lasts for several days, as in the case of 
the salmon,^* the female, during the whole time, is attended by 
the male. After the ova are fertilised they are, in most cases, 
left unprotected by both parents, so that the males and females, 
as far as oviposition is concerned, are equally exposed to danger, 
and both are equally important for the production of fertile ova ; 
consequently the more or less brightly-coloured individuals of 
either sex would be equally liable to be destroyed or preserved, 
and both would have an equal influence on the colours of their 

Certain fishes, belonging to several families, make nests, and 
some of them take care of their young when hatched. Both 

32 G. Pouchet, L'Institut. Nov. 1, 327, pi. xiv. anci xv. 

1871, p. 134. ='•' Yarrell, ' British Fishes,' rcl. 

33 'Proc. Zoolog. Soc' 1865, p. ii. p. 11. 

Chap. XII. Fishes. 345 

sexes of the bright coloured Crenilabrus massa and mdopa work 
together in building their nests with sea-weed, shells, &c.^^ 
But the males of certain fishes do all the work, and afterwards 
take exclusive charge of the young. This is the case with the dull- 
coloured gobies,^'' in which the sexes are not known to differ in 
colour, and likewise with the sticklebacks (Gasterosteus), in which 
the males become brilliantly coloured during the spawning season. 
The male of the smooth- tailed stickleback ((?. leinrus) j^erforms 
the duties of a nurse with exemplary care and vigilance during 
a long time, and is continually employed in gently leading back 
the young to the nest, when they stray too far. He courageously 
drives away all enemies, including the females of his own species. 
It would indeed be no small relief to the male, if the female, after 
depositing her eggs, were immediately devoured by some enemy, 
for he is forced incessantly to drive her from the nest.^^ 

The males of certain other fishes inhabiting South America 
and Ceylon, belonging to two distinct Orders, have the extra- 
ordinary habit of hatching within their mouths or branchial 
cavities, the eggs laid by the females.^® I am informed by 
Professor Agassiz that the males of the Amazoniaa species 
which follow this habit, " not only are generally brighter than 
" the females, but the difference is greater at the spawning-season 
" than at any other time." The species of Geophagus act in the 
same manner ; and in this genus, a conspicuous protuberance 
becomes developed on the forehead of the males during the 
breeding-season. With the various species of Chromids, as 
Professor Agassiz likewise informs me, sexual differences in 
colour may be observed, " whether they lay their eggs in the 
" water among aquatic plants, or deposit them in holes, leaving 
" them to come out witiiout further care, or build shallow nests 
" in the river mud, over which they sit, as our Promotis does. 
" It ought also to be observed that these sitters are among the 
" brightest species in their respective families ; for instance, 
" Hygrogonus is bright green, with large black ocelli, encircled 
" with the most brilliant red." Whether with all the species of 
Chromids it is the male alone which sits on the eggs is not 
known. It is, however, manifest that the fact of the eggs being 

^^ According to the observatioas nals and Mag. of Nat. Hist.' Novem- 

of M. Gerbe ; see Giinther's ' Record ber 1855. 

of Zoolog. Literature,' 1^65, p. '* Prof. Wyman, in ' Proc*. Boston 

194-. Soc. of Nat. Hist.' Sept. 15, 1857. 

2^ Cuvier, ' Rfegne Animal,' vol. Also Prof. Turner, in ' Journal of 

ii. 1829, p. 242. Anatomy and Phys.' Nov. 1, 186(3, 

" See Mr. Waringtou's most p. 78. Dr. Giinther has likewise 

interesting description of the habits described other cases, 
of the Gasterosteus Iciurus, in 'An- 


34^ The Descent of Man. Part II. 

protected or unprotected by the parents, has had little or no 
influence on the differences in colour between the sexes. It is 
further manifest, in all the cases in which the males take 
exclusive charge of the nests and young, that the destruction 
of the blighter-coloured males would be far more influential on 
the character of the race, than the destruction of the brighter- 
coloured females ; for the death of the male during the period of 
incubation or nursing would entail the death of the young, so 
that they could not inherit his peculiarities ; yet, in many of 
these very cases the males are more conspicuously coloured than 
the females. 

In most of the Lophobranchii (Pipe-fish, Hippocampi, &c.) 
the males have either marsupial sacks or hemispherical de- 
pressions on the abdomen, in which the ova laid by the female 
are hatched. The males also shew great attachment to their 
young.^^ The sexes do not commonly differ much in colour; 
but Dr. Gunther believes that the male Hippocampi are rather 
brighter than the females. The genus Solenostoma, however, 
offers a curious exceptional case,'*'' for the female is much more 
vividly-coloured and spotted than the male, and she alone has a 
marsupial sack and hatches the eggs; so that the female of 
Solenostoma differs from all the other Lophobranchii in this 
latter respect, and from almost all other fishes, in being more 
brightly-coloured than the male. It is improbable that this 
remarkable double inversion of character in the female should 
be an accidental coincidence. As the males of several fishes, 
which take exclusive charge of the eggs and young, are more 
brightly coloured than the females, and as here the female Sole- 
nostoma takes the same charge and is brighter than the male, it 
might be argued that the conspicuous colours of that sex which 
is the more important of the two for the welfare of the offspring, 
must be in some manner protective. But from the large number 
of fishes, of which the males are^ either permanently or period- 
ically brighter than the females, but whose life is not at all 
more important for the welfare of the species than that of the 
female, this view can hardly be maintained. When we treat 
of birds we shall meet with analogous cases, where there has 
been a complete inversion of the usual attributes of the two 
sexes, and we shall then give what appears to be the probable 
explanation, namely, that the males have selected the more 
attractive females, instead of the latter having selected, in 

39 Yarrell, ' Hist, of British Fishes of Zanzibar,' by Col. Playfair, 

Fishes,' vol. ii. 183G, pp. 329, 338. 1866, p. 137, has re-examined the 

*" Dr. Gunther, since publishing specimens, and has given me the 

an account of this species in ' The above information. 

Chap. XII. Fishes. 347 

accordance with the usual rule throughout the animal kingdom, 
the more attractive males. 

On the whole we may conclude, that with most fishes, in 
which the sexes differ in colour or in other ornamental charac- 
ters, the males originally varied, with their variations trans- 
mitted to the same sex, and accumulated through sexual 
selection by attracting or exciting the females. In many cases, 
however, such characters have been transferred, either partially 
or completely, to the females. In other cases, again, both sexes 
have been coloured alike for the sake of protection; but in 
no instance does it appear that the female alone has had her 
colours or other characters specially modified for this latter 

The last point which need be noticed is that fishes are known 
to make various noises, some of which are described as being 
musical. Dr. Dnfosse, who has especially attended to this 
subject, says that the sounds are voluntarily produced in several 
ways by different fishes : by the friction of the pharyngeal bones 
— by the vibration of certain muscles attached to the swim- 
bladder, which serves as a resounding board — and by the vibra- 
tion of the intrinsic muscles of the swim-bladder. By this latter 
means the Trigla produces pure and long-drawn sounds which 
range over nearly an octave. But the most interesting case for 
us is that of two species of Ophidium, in which the males alone 
are provided with a sound-producing apparatus, consisting of 
small movable bones, with proper muscles, in connection with 
the swim-bladder,*^ The drumming of the Umbrinas in the 
European seas is said to be audible from a depth of twenty 
fathoms ; and the fishermen of Rochelle assert " that the males 
" alone make the noise during the spawning-time ; and that it 
" is possible by imitating it, to take them without bait."*^ From 
this statement, and more especially from the case of Ophidium, 
it is almost certain that in this, the lowest class of the Verte- 
brata, as with so many insects and spiders, sound-producing 
instruments have, at least in some cases, been developed through 
sexual selection, as a means for bringing the sexes together. 

*' ' Comptes Rendus.' Tom. xlvi. the Dutch translation of this w ork 

1858, p. 353. Tom. xlvii. 1858, p. (vol. ii., p. 36), gives some further 

916. Tom. liv. 1862, p. 393. The particulars on the sounds made by 

noise made by the Umbrinas {Sciccna lishes. 

ciqvMa), is said by some authors to *^ The Rev. C. Kingslcy, in 

be more like that of a flute or organ, < Nature,' May 1870, p. 40. 
than drumming : Dr. Zouteveen, in 


The Descent of Man. 

Part II. 


Urodela. — I will begin with the tailed amphibians. The sexes 
of salamanders or newts often diifer much both in colour and 
structure. In some species prehensile claws are develoiDed on 
the fore-legs of the males during the breeding-season : and at 
this season in the male Triton palmipes the hind-feet are pro- 
vided with a swimming-web, which is almost completely 
absorbed during the winter; so that their feet then resemble 

Fig. 32. Triton cristatus (half natural size, from Bell's ' British Reptiles '). 
Upper figure, male during the breeding-season ; lower figure, female. 

those of the female.^^ This structure no doubt aids the male 
in his eager search and pursuit of the female. Whilst courting 
her he rapidly vibrates the end of his tail. With our common 
newts (Trito7i pur/ctntus and cristntus) a deep, much indented 
crest is developed along the back and tail of the male during the 
breeding-season, which disappears during the winter. Mr. St. 
George Mivart informs me that it is not furnished with muscles, 
and therefore cannot be used for locomotion. As during the 
season of courtship it becomes edged with bright colours, there 
can hardly be a doubt that it is a masculine ornament. In 
many species the body presents strongly contrasted, though 
lurid tints, and these become more vivid during the breeding- 
season. The male, for instance, of our common little newt 
{Triton punctatus) is "brownish-grey above, passing into yellow 

" Bell, 'History of British Reptiles,' 2nd edit. 1849, pp. 156-159. 

Chap. XII. Amphibians. 349 

" beneath, wliicli in the spring becomes a rich bright orange, 
" marked everywhere with round dark si3ots." The edge of the 
crest also is then tipped with bright red or violet. The female 
is usually of a yellowish-brown colour with scattered brown 
dots, and the lower surface is often quite plain.*^ The young 
are obscurely tinted. The ova are fertilised during the act of 
deposition, and are not subsequently tended by either parent. 
We may therefore conclude that the males have acquired their 
strongly-marked colours and ornamental apjiendages through 
sexual selection ; these being transmitted either to the male 
offspring alone, or to both sexes. 

Anura or But rack la. — With many frogs and toads the colours 
evidently serve as a protection, such as the bright green tints 
of tree-frogs and the obscure mottled shades of many terrestrial 
species. The most conspicuously-coloured toad which I ever 
saw, the rhri/niscus nigricans,*^ had the whole ui^per surface of 
the body as black as ink, with the soles of the feet and j^arts of . 
the abdomen spotted with the brightest vermilion. It crawled 
about the bare sandy or open grassy plains of La Plata under a 
scorching sun, and could not fail to catch the eye of every pass- 
ing creature. These colours are probably beneficial by making 
this animal known to all birds of prey as a nauseous mouthful. 

In Nicaragua there is a little frog " dressed in a bright livery 
" of red and blue " which does not conceal itself like most other 
species, but hops about during the daytime, and Mr. Belt says""* 
that as soon as he saw its happy sense of security, he felt sure 
that it was uneatable. " After several trials he succeeded in 
tempting a young duck to snatch up a young one, but it was 
instantly rejected ; and the duck " went about jerking its head, 
" as if trying to throw off some unpleasant taste." 

With respect to sexual differences of colour. Dr. Giinther 
does not know of any striking instance either with frogs or 
toads ; yet he can often distinguish the male from the female, by 
the tints of the former being a little more intense. Nor does 
he know of any striking difference in external structure between 
the sexes, excepting the prominences which become developed 
during the breeding-season on the front-legs of the male, by 
which he is enabled to hold the female.'*^ It is surprising that 

*^ Bell, * History of British Rep- sikrmmensis (Dr. Anderson, * Proc. 

tiles,' 2nd edit. 1849, pp. 146, 151. Zoolog. Soc.,' 1871, p. 204) has two 

*^ 'Zoology of the Voyage of the plate-like callosities on the thorax 

" Beagle," ' 1843. Bell, ibid. p. 49. and certain rugosities on the fingers, 

*** ' The Naturalist in Nicaragua,' which perhaps subserve the same end 

1874, p. 321. as the above-mentioned prominences. 

*'' The male alone of the Bufo 

350 The Descent of Man. Part II. 

these animals have not acquired more strongly-marked sexual 
characters ; for though cold-blooded their passions are strong. 
Dr. GUnther informs me that he has several times found an 
unfortunate female toad dead and smothered from having been 
so closely embraced by three or four males. Frogs have been 
observed by Professor Hoffman in Giessen fighting all day long 
during the breeding-season, and with so much violence, that one 
had its body ripped open. 

Frogs and toads offer one interesting sexual difference, namely, 
in the musical powers possessed by the males; but to speak 
of music, when applied to the discordant and overwhelming 
sounds emitted by male bull-frogs and some other species, seems, 
according to our taste, a singularly inappropriate expression. 
Nevertheless, certain frogs sing in a decidedly pleasing manner. 
Near Eio Janeiro I used often to sit in the evening to listen to a 
number of little Hylse, perched on blades of grass close to the 
water, which sent forth sweet chirping notes in harmony. The 
various sounds are emitted chiefly by the males during the 
breeding-season, as in the case of the croaking of our common 
frog.*^ In accordance with this fact the vocal organs of the 
males are more highly-develojDed than those of the females. In 
some genera the males alone are provided with sacs which open 
into the larynx.^^ For instance, in the edible frog {liana escultnta) 
" the sacs are peculiar to the males, and become, when filled 
" with air in the act of croaking, large globular bladders, stand- 
" ing out one on each side of the head, near the corners of the 
" mouth." The croak of the male is thus rendered exceedingly 
powerful ; whilst that of the female is only a slight groaning 
noise.^" In the several genera of the family the vocal organs 
differ considerably in structure, and their development in all 
cases may be attributed to sexual selection. 


Chelonia. — Tortoises and turtles do not offer well-marked 
sexual differences. In some species, the tail of the male is 
longer than that of the female. In some, the plastron or lower 
surface of the shell of the male is slightly concave in relation to 
the back of - the female. The male of the mud-turtle of the 
United States (Chrysemys picta) has claws on its front-feet 
twice as long as those of the female ; and these are used when 

*8 Bell, 'History of British " J. Bishop, in 'Todd's Cyclop. 

Reptiles,' 1849, p. 93. of Anat. and Phvs.' vol. iv. p.'l503 

*o Bell, ibid. p. 112-114. 

Chap. XII. Reptiles. 351 

the sexes unite.^^ With the huge tortoise of the Galapagos 
Islands {Tedudo nigra) the males are said to grow to a larger 
size than the females: during the pairing-season, and at no 
other time, the male utters a hoarse bellowing noise, which can 
be heard at the distance of more than a hundred yards ; the 
female, on the other hand, never uses her voice.^^ 

With the Testudo degans of India, it is said " that the combats 
" of the males may be heard at some distance, from the noise 
" they produce in butting against each other." ^^ 

Crocodilia. — The sexes apparently do not differ in colour ; nor 
do I know that the males fight together, though this is pro- 
bable, for some kinds make a prodigious display before the 
females. Bartram^* describes the male alligator as striving 
to win the female by splashing and roaring in the midst 
of a lagoon, *' swollen to an extent ready to burst, with its 
" head and tail lifted up, he spins or twirls round on the 
" surface of the water, like an Indian chief rehearsing his feats 
of war." During the season of love, a musky odour is emitted 
by the submaxillary glands of the crocodile, and pervades their 

Ophidia.—'Dr. Giinther informs me that the males are always 
smaller than the females, and generally have longer and slenderer 
tails ; but he knows of no other difference in external structure. 
In regard to colour, he can almost always distinguish the male 
from the female by his more strongly-pronounced tints ; thus 
the black zigzag band on the back of the male English viper is 
more distinctly defined than in the female. The difference is 
much plainer in the rattle-snakes of N. America, the male of 
which, as the keeper in the Zoological Gardens shewed me, can at 
once be distinguished from the female by having more lurid 
yellow about its whole body. In S. Africa the Bucephalus 
mpensis presents an analogous difference, for the female "is 
" never so fully variegated with yellow on the sides as the 
" male." ^^ The male of the Indian Dipsas ajnodon, on the 
other hand, is blackish-brown, with the belly partly black, 
whilst the female is reddish or yellowish-olive, with the belly 
either uniform yellowish or marbled with black. In the Tragops 
dispar of the same country, the male is bright green, and the 

51 Mr. C. J. Maynard, 'The British India,' 1864, p. 7. 
American Naturalist,' Dec. 1869, p. ^* ' Travels through Carolina, 

555. &c., 1791, p. 128. 

*2 See my < Journal of Researches ^^ Owen, * Anatomy of Verte- 

during the Voyage of the " Beagle," ' bratcs,' vol. i. 1866, p. 615. 
1845, p. 384. 5« Sir Andrew Smith, ' Zoolo?. of 

53 Dr. Giinther, 'Reptiles of S. Africa: Reptilia,' 1849, pi. xt 

352 The Descent of Man. Part II. 

female bronze-coloured.^'' No doubt the colours of some snakes 
are protective, as shewn by the green tints of tree-snakes, and 
the various mottled shades of the species which live in sandy 
places ; but it is doubtful w^iether the colours of many kinds, 
for instance of the common English snake and viper, serve to 
conceal them; and this is still more doubtful with the many 
foreign species which are coloured with extreme elegance. The 
colours of certain species are very different in the adult and 
young states.^^ 

During the breeding-season the anal scent-glands of snakes are 
in active function f^ and so it is with the same glands in lizards, 
and as we have seen with the submaxillary glands of crocodiles. 
As the males of most animals search for the females, these 
odoriferous glands probably serve to excite or charm the female, 
rather than to guide her to the spot where the male may be 
found. Male snakes, though appearing so sluggish, are amorous ; 
for many have been observed crowding round the same female, 
and even round her dead body. They are not known to 
fight together from rivalry. Their intellectual powers are 
higher than might have been anticipated. In the Zoological 
Gardens they soon learn not to strike at the iron bar with which 
their cages are cleaned ; and Dr. Keen of Philadelphia informs 
me that some snakes which he kept, learned after four or five 
times to avoid a noose, with which they were at first easily 
caught. An excellent observer in Ceylon, Mr. E. Layard, saw '^^ 
a cobra thrust its head through a narrow hole and sw^allow a 
toad. " With this encumbrance he could not withdraw him- 
" self; finding this, he reluctantly disgorged the precious mor- 
" sel, which began to move off; this was too much for snake 
" philosophy to bear, and the toad was again seized, and again 
" was the snake, after violent efforts to escape, compelled to part 
" with its prey. This time, however, a lesson had been learnt, 
" and the toad w^as seized by one leg, withdrawn, and then 
" swallowed in triumph." 

The keeper in the Zoological Gardens is positive that certain 
snakes, for instance Crotalus and Python, distinguish him from 
all other persons. Cobras kej)t together in the same cage 
apparently feel some attachment towards each other.*^^ 

" Dr. A. Giinther, 'Reptiles of brates,' vol. i. 1866, p. 615. 

British India/ Ray Soc. 1864, pp. «<> ' Rambles in Cevlon.' in 'Anuals 

304, 308. and Mag. of Nat. Hist.' 2nd series, 

58 Dr. Stoliczka, ' Journal of vol. ix. 1852, p. 333. 

Asiatic Soc. of Bengal,' vol. xxxix. **! Dr. Giinther, * Reptiles of 

1870, pp. 205, 211. British India,' 1864, p. 340. 

^^ Owen, ' Anatomy of Verte- 

Chap. XII. Reptiles. 353 

It does not, however, follow because snakes have some 
reasoning: power, strong passions and mutual affection, that they 
should likewise be endowed with sulhcient taste to admire 
brilliant colours in their partners, so as to lead to the adorn- 
ment of the species through sexual selection. Nevertheless, it is 
difficult to account in any other manner for the ext