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Selection in Relation to Sex. 


Fellow of the Royal Society, Etc. 


New Edition, Revised and Augmented. Complete in One Volume. 



AUG 1 8 1993 

^/?S/TY OF ^0!S 





or THE 



Vol. I. 



27, note. 

32, note. 









90, note. 





124, note. 

125, note. 



,=P3UT^IIiWI> |?a»>r-^*t^i*^^»y.^. 


30, note. 

40, note. 



88, 89 








128, note. 


132, note. 

135, note. 



54, note. 

52-53, note. 

70, note. 

Discussion on the rudimentary points in the 
human ear revised. 

Cases of men born with hairy bodies. 

Mantegazza on the last molar tooth in man. 

The rudiments of a tail in man. 

Bianconi on homologous structures, as ex- 
plained by adaptation on mechanical 

Intelligence in a baboon. 

Sense of humor in dogs. 

Further facts on imitation in man and 

Reasoning power in the lower animals. 

Acquisition of experience by animals. 

Power of abstraction in animals. 

Power of forming concepts in relation to 

Pleasure from certain sounds, colors, and 

Fidelity in the elephant. 

Gallon on gregariousness of cattle. 

Parental affection. 

Persistence of enmity and hatred. 

Nature and strength of shame, regret, and 

Suicide among savages. 

The motives of conduct. 

Selection, as applied to primeval man. 

Resemblances between idiots and animals 

Division of the malar bone. 

Supernumerary mammae and digits. 

Further cases of muscles proper to animals 
appearing in man. 

Broca : average capacity of skull diminished 
by the preservation of the inferior mem- 
bers of society. 



First Edition. 
Vol. I. 






flo8, note. 













177, note. 






























307, note. 









j Belt on advantages to man from his hair* 
( lessness. 

j Disappearance of the tail in man and certain 
\ monkeys. 

j Injurious forms of selection in civilized 
\ nations. 

j Indolence of man, when free from a struggle 
\ for existence. 

j Gorilla protecting himself from rain with 
\ his hands. 
Hermaphroditism in fish. 
Rudimentary mammoe in male mammals, 
j Changed conditions lessen fertility and 
/ cause ill-health among savages. 
Darkness of skin a protection against the 

Note 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 caus- 
ing differences between the sexes. 
Period of development of protuberances on 
birds' heads determines their transrais* 
sion to one or both sexes. 
Causes of excess of male births. 
Proportion of the sexes in the bee family. 
Excess of males perhaps sometimes detef* 

mined by selection. 
Bright colors of lowly organized animals. 
Sexual selection among spiders. 
Cause of smallness of male senders. 
Use of phosphorescence of the glow-worm* 
The humming noises of flies. 
Use of bright colors to Hemiptera (bugs). 
Musical apparatus of Homoptera. 
Development of stridulating apparatus in 

Herman Mliller on sexual differences of 

Sounds produced by moths. 
Display of beauty by butterflies. 
Female butterflies, taking the more active 
part in courtship, brighter than their 
Further cases of mimicry in butterflies and 

Cause of bright and diversified colors ol 



./' Vol. II. 






































556 ^ 







9 et seq. 

dw et seq. 





Brusli-]ike scales of male Mallotus, 
\ Furthei facts on courtship of fishes, and 

tlie jpawning of Macropus. 
Dufosse on tht, sounds macJ^ by fishes. 
Belt on a frog protected by bright coloring. 
Further facts on mental powers of snakes. 
Sounds produced by snakes ; the rattle- 
Combats of Chameleons. 
Marshall on protuberances on birds* heads. 
Further facts on display by the Argus 

Attachment between paired birds. 
Female pigeon rejecting certain males. 
Ali^ino birds not finding partners, in a 

state of nature. 
Direct action of climate on birds* colors. 
Further facts on the ocelli in the Argu^ 

Display by humming-birds in courtship. 
Cases with pigeons of color transmitted to 

one sex alone. 
Taste for the beautiful permanent enough 

to allow of sexual selection with the lower 

Horns of sheep originally a masculine char- 
Castration affecting horns of animals. 
Prong-horned variety of Cervus virgin* 

Relative sizes of male and female whales 

and seals. 
Absence of tusks in male miocene pigs. 
Dobson on sexual differences of bats. 
Reeks on advantage from peculiar coloring. 
Difference of complexion in men and women 

of an African tribe. 
Speech subsequent to singing. 
Schopenhauer on importance of courtship 

to mankind. 
Revision of discussion on communal mar* 

riages and promiscuity. 
Power of choice of woman in marriage, 

among savages. 
Long-continued habit of plucking out hairs 

may produce an inherited effect. 


Ijmtonucnoir, • » • ^ ?^ •/ ^^ # i. % n 



The Evidence of the Descent of Man from some Lower 
Form, 21 

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, etc. — 
The bearing of these three great classes of facts on the origin of 


On the Manner of Development of Man from some Lower 
Form, 4a 

Variability of body and mind in man — Inheritance — Causes of varia* 
bility — 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. 


Comparison of the Mental Powers of Man and the Lower 
Animals, 8c 

The difference in mental power between the highest ape and the lowest 
savage, immense — Certain instincts in common — The emotions- 
Curiosity — Imitation — Attention — Memory — Im^ination"^ 


Reason — Progressive improvement — Tools and weapons used by 
animals — Abstraction, self-a)nsciousness— -Language — Sense oi 
beauty — Belief in God, spiritual agencies, sm>erstilions. 


Comparison of the Mental Powers of Man and the I>ower 

Animals — continued^ . .112 

The moral sense — Fundamental proposition — The qualities of social 
animals — Origm of si^ciahilily — Struggle between opposed in- 
stincts — Man a social animal — The more enduring social instincts 
conquer other less persistent instincts — The social virtues alone 
regarded by savages — The self-regarding virtues acquired at a 
later stage of development — The miportance of the judgment of 
the members of the same community on conduct — Transmission 
of moral tendencies — Summary. 


On the Development of the Intellectual and Moral Facul- 
ties DURING Primeval and Civilized Times, . , . 14J 

Advancement of the intellectual powers through natural selection- 
Importance of imitation — Social and moral faculties — Their de- 
velc "^nient within the limits of the same tribe — Natural selection 
as affecting civilized nations — Evidence that civilized nations were 
once barbarous. 


On the Affinities and Genealogy of Man, • . . . 169 

Fbsition of man in the animal series — The natural system genealogical 
— Adaptive characters of slight value — Various small points of re- 
semblance between man and the qiiadrumana — Rank of man in 
the natural system— Birthplace and a«tiqmty of man — Absence 
of fossil connecting-links — Lower stages in the genealogy of man, 
as inferred, firstly from his affinities and secondly from his 
structure — Early androgynous condition of the Vertebrata— 


On t^e Races op Man, , . • • » • • 18I 

Tiie nature and value of specific characters — Application to the races 
of man — Arguments in favor of, and opposed to, ranking the so- 
called races of man as distinct species— Sub-species — Monogenists 
and polygenists — Convergence of character — Numerous points of 
resemblance in body and mind between the most distinct races of 
m.^ — The state of man when he first spread over the earth— 
Each race not descended from a single pair — The extinction q£ 




Voes---T**'^ formation of races — The effects of crossir.g— Slight 
faflaence of the direct action of the conduions of life — Slight at 
no ibiluCJice of natural selection — Sexual selection. 



P!l/»CIPLES OP Sexual Selection, 228 

^londary 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 
ihfi male — Choice exerted by the female — Sexual compared with 
'ttatural selection — Inheritance at corresponding periods of life, at 
corresponding seasons of the year, and as limited by sex — Rela- 
tions between the several forms of inheritance — Causes why one 
«ex and the young are not modified through sexual selection- 
Supplement on the proportional numbers of the two sexes through- 
out the animal kingdom — The proportion of the sexes in relation 
to natural selectioiu 


Secondary Sexual Characters in the Lower Classes of the 
Animal Kingdom, 278 

These characters absent in the lowest classes — Brilliant colors — Mol» 
lusca — Annelids — Crustacea, secondary sexual characters strongly 
developed ; dimorphism ; color ; characters not acquired before 
maturity — Spiders, sexual colors of ; stridulation by the males— 


Secondare Sexual Characters of Insects, .... 293 

Diversified structures possessed by the males for seizing the females — 
Differences between the sexes, of which the meaning is not un- 
derstood — Difference in size between the sexes — Thysanura— 
Diptera — Hemiptera — Homoptera, musical powers possessed by 
the males alone — Orthoptera, musical l istruments of the males, 
much diversified in structure ; pugnacity ; colors — Neuroptera, 
sexual differences in color — Hymcnoptera, pugnacity and colors 
— Coleoptera, colors ; furnished with great horns, apparently as 
an ornament ; battles ; stridulating organs generally commoa to 
both sexes. 

14, CONTEm-TS, 




Moths), 325 

-Courtship of butterflies — Battles — Ticking noise — Colors common to 
both sexes, or more brilliant in the males — Examples — Not due 
to the direct action of the conditions of life — Colors adapted for 
protection — Colors of moths — Display — Perceptive powers of the 
Lepidoptera — Variability — Causes of the difference in color be- 
tween the males and females — Mimicry, female butterflies more 
brilliantly colored than the males — Bright colors of caterpillars- 
Summary and concluding remarks on the secondary sexual char" 
acters of insects — Birds and insects compared. 


Sbcondary Sexual Characters of Fishes, Amphibians, and 
Repi'iles, 399 

Fishes : Courtship and battles of the males — Larger size of the 
females — Males, bright colors and ornamental appendages ; other 
strange characters — Colors and appendages acquired by the males 
during the breeding-season alone — Fishes with both sexes brill- 
iantly colored — Protective colors — The less conspicuous colors of 
the female cannot be accounted for on the principle of protection 
—Male fishes building nests, and taking charge of the ova and 
young. Amphibians : Differences in structure and color between 
the sexes — Vocal organs. Reptiles : Chelonians — Crocodiles- 
Snakes, colors in some cases protective — Lizards, battles of— 
Ornamental appendages — Strange differences in structure between 
the sexes — Colors — Sexual differences almost as great as with 


Secondary Sexual Characters of Birds, - • • • 378 

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


Birds — contintud^ •••>•••••( 4S| 

Choice exerted by the female — Length of courtship — ^Unpaired birds 
—Mental qualities and taste tor the beautiful — Preference or an* 
t^thy shown by the female for particular males — Variability of 



birds— Variations sometimes abrupt — Laws of variation— Forma- 
tion of ocelli— Gradations of character — Case of Peacock, Argus 
pheasant, and Urosticte. 

Biros — continued^ ••• •• /^5 

Piscussion as to why the males alone of some species, and both sexes 
of others, are brightly colored — On sexually-limited inheritance, 
as applied to various structures and to brightly-colored plumage 
— Nidification in relation to color — Loss of nuptial plumage dur- 
ing the winter. 


Birds — concluded^ .•••• 485 

The immature plumage in relation to the character of the plumage in 
both sexes when adult — Six classes of cases — Sexual differences 
between the males of closely allied or representative species^ — The 
female assuming the characters of the male — Plumage of the 
young in relation to the summer and winter plumage of the adults 
—On the increase of beauty in the birds of the world — Protective 
coloring — Conspicuously-colored birds — Novelty appreciated — 
Summary of the four chapters on birds. 


Secondary Sexual Characters of Mammals, . • . . 523 

The law of battle — Special weapons, confined to the males — Cause of 
absence of weapons in the female — Weapons common to both 
sexes, yet primarily acquired by the male — Other uses of such 
weapons — Their high importance — Greater size of the male- 
Means of defence — On the preference shown by either sex in the 
pairing of quadrupeds. 


Secondary Sexual Characters of Mammals — continued^ . 54S 

Voice — Remarkable sexual peculiarities in seals — Odor — Development 
of the hair — Color of the hair and skin — Anomalous case of the 
female being more ornamented than the male — Color and orna- 
ments due to sexual selection — Color acquired for the sake of 
protection — Color, though common to both sexes, often due to 
sexual selection — On the disappearance of spots and stripes in 
adult quadrupeds — On the colors and ornaments of the Quadru- 
nsina — Summary. 

10 CONTEmS. 



Secondary Sexual Characters ok Man, , / ^ , =79 

Diflerences between man and woman — Causes of such differences, and 
of certain characters common to both sexes — Law of battle — Dif- 
ferences in mental powers, and voice — On the influence of beauty 
in determining the marriages of mankind — Attention paid by sav- 
ages to ornaments — Their ideas of beauty in woman — The ten- 
dency to exaggerate each natural peculiarity. 


Secondary Sexual Characters of Man — continued, . • • 608 

On the effects of the continued selection of women according to a 
different standard of beauty in each race — On the causes which 
interfere with sexual selection in civilized and savage nations — 
Conditions favorable to sexual selection during primeval times — 
On the manner of action of sexual selection with mankind — On 
the women in savage tribes having some power to choose their 
husbands — Absence of hair on the body, and development of the 
beard — Color of the skin — Summary. 


general Summary and Conclusion, 630 

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

1ND£X, •••<)••••••• •645 





The nature of the following work will be best understood by a 
brief account of how it came to be written. During many 
years I collected notes on the origin or descent of man, without 
any intention of pubhshing 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 " hght would be thrown on the 
origin of man and his history; " and this implies that man 
must be included with other organic beings in any general con- 
clusion respecting his manner of appearance on this earth. Now 
the case wears a wholly different aspect. When a naturalist 
like Carl Vogt ventures to say in his address as President of the 
National Institution of Geneva (1869), **personne, en Europe 
au moins, n'ose plus soutenir la creation independante et de 
toutes pieces, des especes," it is manifest that at least a large 
number of naturalists must admit that species are the modified 
descendants of other species ; and this especially holds good 
with the younger and rising naturalists. The greater number 
accept the agency of natural selection ; though some urge, 
whether with justice the future must decide, that I have greatly 
overrated its importance. Of the older and honoied chiefs in 
atural science, many unfortunately are still opposed to evoltt- 
tion in every foroi. 


In consequence of the views now adopted by tnost nntijralists, 
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 api)licable to man. This seemed 
all the more desirable, as I had never deliberately api)lied these 
views to a species taken singly. When we confine our attention 
to any one form, we are deprived of the weighty arguments 
derived from the nature of the affinities which connect to- 
gether whole groups of organisms — their geographical distribu- 
tion in past and present times, and their geological succession. 
The homological structure, embryological development, and 
rudimentary 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 favor of 
the principle of gradual evolution. The strong support derived 
from the other arguments should, however, always be kept be- 
fore the mind. 

The sole object of this work is to consider, firstly, whether 
man, like every other species, is descended from some pre- 
existing form ; secondly, the manner of his development ; and 
thirdly, the value of the differences between the so-called 
races of man. As I shall confine myself to these points, it will 
not be necessary to describe in detail the differences between 
the several races — an enormous subject which has been fully 
discussed in many valuable works. The high antiquity of man 
has recently been demonstrated by the labors of a host of emi- 
nent men, beginning with M. Boucher de Perthes ; and this 
is the indispensable basis for understanding his origin. I 
shall, therefore, take this conclusion for granted, and may refer 
my readers to the admirable treatises of Sir Charles Lyell, Sir 
John Lubbock, and others. Nor shall I have occasion to 
do more than to allude to the amount of difference between 
man and the anthropomorphous apes ; for Prof. Huxley, in the 
opinion of most competent judges, has conclusively shown 
that in ev^y visible character man differs less from the higher 
apes than these do from the lower members of the a*une ^rder 
of Primates. 

This work contains hardly any original facts in regard to 
man ; but as the conclusions at which I arrived, after drawing 
up a rough draught, appeared to me interesting, I thought that 
they might interest othersc It has often and confidently beea 

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 asser-t 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 con- 
clusion, which has lately been maintained by several eminent 
naturalists and philosophers ; for instance, by Wallace, Huxley, 
Lyell, Vogt, Lubbock, Biichner, Rolle, etc.,^ and especially by 
Hackel. This last naturahst, besides his great work, '' Generelle 
Morphologic " (1866), has recently (1868, with a second edit, 
in 1870), published 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 prob- 
ably never have completed it. Almost all the conclusions at 
which I have arrived I find confirmed by this naturalist, whose 
knowledge on many points is much fuller than mine. Where- 
ever I have added any fact or view from I'rof. Hackers writ- 
ings, I give his authority in the text; other statements I leave 
as they originally stood in my manuscript, occasionally giving 
in the foot-notes references to his works, as a confirmation of 
the more doubtful or interesting points. 

During many years it has seemed to me highly probable that 
sexual selection has played an important part in differentiating 
the races of man ; but in my " Origin of Species " (first edi- 
tion, 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. ^ Con- 
sequently the second part of the present work, treating of 
S4?xual selection, has extended to an inordinate length, compared 
with the first part ; but this could not be avoided. 

I had intended adding to the present volumes an essay on the 
expression of the various emotions by man and ll^e lower 

* As the works of the first-named authors 1867, p. 81) a rery curious paper on rudi- 

are so well Known, I need not give the titles ; mentary characters, as bearing on the origin 

but as those of the latter are less well known of man. Another work has (1869) been pub- 

in England, I will give them : " Sechs lished by Dr. Francesco Barra£;o, bearing in 

Vorlesungen iiber die Darwin' sche Theorie : " Italian the title of " Man, made in the image 

zweite Auflage, 1868, von Dr. L. Biichner ; of God, was also made in the image of the 

translated into French under the tide " Con- ape." 

f^rences sur la Theorie Darwinienne," 1869. ' Prof. Hackel was the only author who, 

*' Der Mensch, im Lichtc der Darwin'sche at the time when this work first appeared, 

Lehre," 1865, von Dr. F. Rolle. I will not had discussed the subject of sexual seleo 

att<;mpt to give references to all the authors tion, and had seen its full importance, since 

who have taken the same side of the ques- the publication of the " Origm ; " and this 

tion. Thus G. Canestrini h^s published he did in a very able manner in bia variodt 

I" Annuario della Soc d. Nat.." Modena. u.•'^rl:s. 


animals. My attention was called to this subject many years 
ago by Sir Charles Ik-ll's admirable work. This illustrious 
anatomist maintains that man is endowed with certain muscles 
solely for the sake of expressing his emotions. As tliis viev? 
is obviously opposed to the belief that man is descended from 
some other and lower form, it was necessary for me to consider 
it. I likewise wished to ascertain how far the emotions are ex- 
pressed in the same manner by the different races of man. 
But owing to the length of the present work, I have thou^t ll 
bctcer to reserve my essay for separate publicatioo. 





l^ature 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, etc. — The bearing of 
these three great classes of facts on the origin of man. 

He who wishes to decide whether man is the modified descend- 
ar.t of some pre-existing form would probably first inquire 
whether man varies,- however slightly, in bodily structure and 
in mental faculties ; and if so, whether the variations are trans- 
mitted to his offspring in accordance with the laws which 
prevail with the lower animals. Again, are the variations the 
result, as far as our ignorance permits us to judge, of the same 
general causes, and are they governed by the same general laws, 
as in the case of other organisms ; for instance, by correlation, 
the inherited effects of use and disuse, etc.? Is man subject to 
similar malconformations, the result of arrested development, 
cf reduplication of parts, etc., and does he display in any of 
his anomalies reversion to some former and ancient type of 
structure ? It might also naturally be inquired 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, whea 


crossed, do they react on each other in the first and succeeding 
generations ? And so with many other points. 

The incjuirer would next ccme to the important point 
"vhether man teixls to increase at so rapid a rate as to lead to 
occasional severe struggles for existence , and consequently to 
beneficial variations, whether in body or rnind, 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 comparisoa 
with those of the lower animals, will be considered. 

The Bodily Structure of Man. — -It is notorious that man is 
constructed on the same general type or model as other mam- 
mals. All the bones in his skeleton can be compared with 
corresponding bones in a monkey, bat, or seal. So it is with his 
muscles, nerves, blood-vessels, and internal viscera. The brain, 
the most important of all the organs, follows the same law, as 
shown 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 otherv/ise their 
mental powers would have been the same. Vulpian ' remarks ; 
*' Les differences reelles qui existent entre I'encephale de 
I'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 anato- 
miques de son cerveau que ceux-ci ne le sont non-seulement des 
autres mammi feres, 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 

' " Grosshirnwindun?en des Menschen," " «< Lg^ous sut la Physiologic" 1866, p. 

1868,5.96. The conclasions of this author, 890, as quoted by M. Dally, "L'Ordr^ 

as well as those of Graiiolet and Aeby, con- des Primates et le Transformisme," i8<8| 

earning the brain, will be discussed by Prof. p. 29. 
Huxley in the Appendix alluded to in thft 
Pre^ce to this edition. 


the higher mammals in the structure of the brain and all other 
parts of the body. 

It may, however, be worth while to specify a few points, not 
directly or obviously connected with structure, by which this 
correspondence or relationship is well shown. 

Man is liable to receive from the lower animals, and to com- 
municate to them, certain diseases, as hydrophobia, variola, the 
glanders, syphilis, cholera, herpes, etc.;^^ and this fact proves 
the close similarity * of their tissues and blood, both in minute 
structure and composition, far more plainly than does their 
comparison under the best microscope, or by the aid of the best 
chemical analysis. Monkeys are liable to many of the same non- 
contagious diseases as we are ; thus Rengger,^ who carefully 
observed for a long time the Cebiis Azarce in its native land, 
found it liable to catarrh, with the usual symptoms, and which, 
-when often recurrent, led to consumption. These monkeys 
suffered also from apoplexy, inflammation of the bowels, and 
cataract in the eye. The younger ones when shedding their 
milk-teeth often died from fever. Medicines produced the same 
effect on them as on us. Many kinds of monkeys have a strong 
taste for tea, coffee, and spirituous liquors; they will also, as I 
have myself seen, smoke tobacco with pleasure.® Brehm asserts 
that the natives of northeastern Africa catch the wild baboons 
by exposing vessels with strong beer, by which they are made 
drunk. He has seen some of these animals, which he kept in 
confinement, in this state ; and he gives a laughable account of 
their behavior and strange grimaces. On the following morn- 
ing 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 mon- 
key, 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 

'Dr. W. Lauder Lindsay has treated this ^ " Naturgeschichte der Saugethiere von 

subject at some length in the "Journal of Paraguay," 1830, s. 50. 

Mental Science," July, 1871 ; and in the * The same tastes are common to some 

" Edinburgh Veterinary Review," July, 1858. animals much lower in the sca'< . Mr. A. 

* A Reviewer has criticised (" British Nicols informs me that he kept \^\ Queens- 
Quarterly Review," Oct. i, 1871, p. 472) land, in Australia, three individuals of the 
what I have here said with much s('verity Phaseolarctus cinereus ; and that, without 
and contempt ; but, as I do not use the term having been taught in any way, they ac- 
identity, I cannot see that I am greatly in quired a strong taste for rum, and for smok- 
error. There appears to me a strong analogy ing tobacco. 

between the same infection or contagion pro- "^ Krehm, "Thierleben," B. i. 1864, s. 75, 

ciucing the same result, or one closely similar, 86. On the Ateles, s. 105. For other aflaio- 

in t\yo distinct animals, and the testing of twa gous statements, see s. 25, loy. 
distinct fluids by the same chemical reagent. 

24 THE DESCENT OF MANi [part t 

monkeys and man, and how similarly their whole nervous 
system is affected. 

Man is infested with internal parasites, sometimes causing 
fatal 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, etc., as well as in mind, in the same manner as do the 
two sexes of many mammals. So that the correspondence in 
general structure, in the minute structure of the tissues, in 

8 Dr. W. Lauder Lindsay, "Edinburgh curatores ejusdem loci et alii e ministris con- 
Vet Review," July, 1858, p. 13. firmaverunt. Sir Andrew Smith et Brehm 

" With respect to insects see Dr. Laycock, notabant idem in Cynocjphalo. Illustrissi- 

*'On a General Law of Vital Periodicity," mus Cuvier etiam narrat multa de hSc re, 

" British Association," 1842. Dr. Mac- qua ut opinor, nihil tui-pius potest indicari 

culloch, " Silliman's North American Journal inter omnia hominibus et Quadruma.iis com- 

of Science," vol. xvii. p. 305, has seen a dog munia. Narrat enim CynocephaLm quen- 

suffering from tertian ague. Hereafter I dam in furorem incidere aspectu leminarum 

shall return to this subject. aliquarum, .sed nequaqnam accendi tanto 

'*' 1 have given the evidence on this head furore ab omnibus. Semper eligebatjuniores, 

in my "Variation of Animals and Plants et dignoscebat in turba, et advocabat voce 

under Domestication," vol. ii. p. 15, and gestuque." 

more could be added. "" This remark is made with respect to 

" " Mares e diversis generibus Quadru- Cynocephalus and the anthropomorphous 

manorum sine dubio dignoscunt feminas apes by Geoffroy Saint-Hilaire and F. 

humanas a maribus. Primum, credo, odor- Cuvier, " Hist. Nat. des Mammiflres," torn, 

atu. postea aspectu. Mr. Youatt, qui diu in i. i8?4. 

Hortis Zoologicis (Bestiariis) medicus ani- '^ Huxley, "Man's Piace in Nature^** 

malium erat, vir in rebus obser\ andis cautus 1863, p. 34. 
et sagax, hoc mihi cercissime nrobavit. «t 


chemical composition and in constitution, between man and the 
higher animals, especially the anthropomorphous apes, is ex- 
tremely close. 

Embryonic Development. — Man is developed from an ovule, 
about the 125th of an inch in diameter, which differs in no 
respect from the ovules of other animals. The embryo itself at 
a very early period can hardly be distinguished from that of 
other members of the vertebrate kingdom. At this period 
the arteries run in arch-like branches, as if to carry the blood 
to branchiae which are not present in the higher vertebrata, 
though the slits on the sides of the neck still remain (/, ^, 
fig. i), marking their former position. At a somewhat later 
period, when the extremities are developed, *'the feet of liz- 
ards 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 develop- 
ment that the young human being presents marked differ- 
ences 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 authori- 
ties, it would be superfluous on my part to give a number of 
borrowed details, showing that the embryo of man closely 
resembles that of other mammals. It may, however, be added, 
that the human embryo likewise resembles certain low forms 
when adult in various points of structure. For instance, the 
heart at first exists as a simple pulsating vessel ; the excreta 
are voided through a cloacal passage ; and the os coccyx projects 
hke a true tail, ** extending considerably beyond the rudi- 
mentary legs. "^^ In the embryos of all air-breathing vertebrates, 

*< •• Man's Place in Nature," 1863, p. davs old. The internal viscera have been 

67. omitted, and the uterine appendages in both 

J6 The human embryo (upper fig.) is from drawings removed. I was directed to these 

Ecker, "Icones Phys.," 1851-1859, tab. xxx. figures by Prof. Huxley, from whose work, 

fig. 2. This embryo was ten lines in length, " Man's Place in Nature," the ideaof givmg 

so that the drawing is much magnified. The them was taken. Hackel has also givei 

embryo of the dog is from Bischoff, " Ent- analogous drawings in his '* Schopfungs- 

wicklungsgeschichie des Hiinde-Eies," 1845, geschichte." 

tab. xi. fig. 42 B. This drawing is five times '« Prof Wyman in " Proc. of American 

pagnifieo, the embryo being twcjitw-five Ac^d. of Sciences," vol. iv. i86o, p. 17. 

(BH- Vol«t 


(PA&T ft 


*\g. I. Upper figure human embryo, from Ecker. Lower figure that of a dog, &om 
Bischoff. a. Fore-brain, cerebral hemispheres, etc. b. Mid-brain, corpora qiiadrigemina, 
c. Hind-brain, cerebellum, medulh oblongata, d. Eye. e. Ear. f. First visceral arch. 
g. Second visceral arch. H. Vertebral columns and muscles in process of development. 
i. Anterior extremities. K. Posterior extremities. L. Tail or os coccyx. 

certain glands, called the corpora Wolffiana, correspond with 
and act like the kidneys of mature fishes. ^'^ Even at a later 

*^ Qwen, "Anatomy of Vertebrates," vol. i. p. 533. 

CHAP. I.j RUDlMEirrS. ^ 

embryonic period, some striking resemblances between man and 
the lower animals may be observed. Bischoff says that the 
convolutions of the brain in a human foetus at the end of the 
seventh month reach about the same stage of development as in 
a baboon when adult. ^^ The great toe, as Prof. Owen remarks/' 
*^ which forms the fulcrum when standing or walking, is per- 
haps the most characteristic peculiarity in the human struct- 
ure;" but in an embryo, about an inch in length, Prof. Wy- 
man ^ 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 

Rudiments. — ^-This subject, though not intrinsically more im- 
portant than the two last, will for several reasons be treated 
here more fully. ^'^ Not one of the higher animals can be named 
which does not bear some part in a rudimentary condition ; 
and man forms no exception to the rule. Rudimentary organs 
must be distinguished from those that are nascent ; though in 
some cases the distinction is not easy. The former are either 
absolutely useless, such as the mammas 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 possess- 
ors, that we can hardly suppose that they were devekjped un- 
der the conditions which now exist. Organs in this latter state 
are not strictly rudimentary, but they are tending in this 
direction. Nascent organs, on the other hand, though not fully 
developed, are of high service to their possessors, and jire ca- 
pable of further development. Rudimentary organs are emi- 

«8 " Die Grosshirnwindungen des Men- ratteri rudimentali in ordine all' origine dd 

schen," 1868, s. 95. ^ uomo" (" Annuario della Soc. d. Nat.," Mo- 

*• " Anatoiny of Vertebrates," vol. i. p. dena, 1867,9. 81), by G. Canestrini, to which 

S53' . paper I am consitierabiy indebted. Hackel 

a" " Proc. Soc. Nat. Hist." Boston, 1863, has given admirable discussions on this 

vol. ix. p. 185. whole subject, under the title of Dysteleol- 

5» "Man's Place in Nature," p. 65. ogy, in his " Generelle Morphologie," an<) 

'* I had written a rough copy of th's " Schbpfungsgeschichte." 
chapter before reading a valuable paper, " Ca- 


nently variable ; and this is partly intelligible, as they are use- 
less, or nearly useless, and consequently arc no longer subjected 
to natural selection. They often become wholly sui)i)ressed. 
When this occurs, they are nevertheless liable to occasional re- 
appearance through reversion — a circumstance well worthy of 

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 "■ dis- 
use ' ' 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 anyway less habitually active. Rudiments, how- 
ever, may occur in one sex of those parts which are normally 
present in the other sex ; and such rudiments, as we shall here- 
after 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 compen- 
sation and economy of growth ; but the later stages of reduc- 
tion, 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 difficult to understand. The 
final and complete suppression of a part, already useless and 
much reduced in size, in which case neither compensation nor 
economy can come into play, is perhaps intelligible by the aid 
of the hypothesis of pangenesis. But as the whole subject of 
rudimentary organs has been discussed and illustrated in my 
former works,^ I need here say no more on this head. 

Rudiments of various muscles have been observed in many 
parts of the human body,^ and not a few muscles which are 
regularly present in some of the lower animals can occasionally 
be detected in man in a greatly reduced condition. Every- 
one must have noticed the power which many animals, espe- 
cially horses, possess of moving or twitching their skin ; and this 

" Some good criticisms on this subject des Sciences Nat." 3d series. Zoolog. 1852, 

have been given by Messrs. Murie and torn, xviii. p. 13) describes and figures rudi- 

Mivart, in "Transact. Zoolog. Soc." 1869, ments of what he calls the " muscle p^dieux 

vol. vii. p. Q2. de la main," which he says is sometimes 

2* " Variarion of Animals and Plants un- " infiniment petit." Another muscle, called 

der Domestication," vol. ii. pp. 317 and 397. "le tibial post^rieur," is generally quite 

See also "Origin of Species," 5th edit. p. absent in the hand, but appears trom time 

r;35. to time in a more or less rudimentary coa* 

^' r^or instance M. Richard (" Annates dition. 


is effected by \hQ panm cuius carnosus. Remnants of this mus« 
cle in an efficient state are found in various parts of our bodies '> 
for instance, the muscle on the forehead, by which the eye- 
brows are raised. TYvQplatysma myoides, which is well devel- 
oped on the n(^ck, belongs to this system. Prof. Turner, of 
Edinburgh, has occasionally detected, as he informs me, mus- 
cular fasciculi in five different situations, namely in the axlilae, 
near the scapulae, etc., all of which must be referred to the 
system of the pa?iniculus. He has also shown ^^ that the mus- 
cuius sternalis or sternalis bruforufn, which is not an extension 
of the rectus abdominalis^ but is closely allied to the pannicu- 
lus, occurred in the proportion of about three per cent, in 
upward of 600 bodies: he adds, that this muscle affords ''an 
excellent illustration of the statement that occasional and 
rudimentary structures are especially liable to variation in ar- 
rangement. ' ' 

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 Can- 
dolle 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 be- 
came divided eight generations ago into two branches ; so that 
the head of the above-mentioned branch is cousin in the sev- 
enth degree to ths 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, prob- 
ably derived from our remote semi-human progenitors ; since 
many monkeys have, and frequently use, the power of largely 
moving their scalps up and down.^ 

The extrinsic muscles which serve to move the external ear, 
and the intrinsic muscles which move the different parts, are 
in a rudimentary condition in man, and they all belong to the 
system of the panni cuius ; they are also variable in develop- 

" Prof. W. Turner, " Proa Royal Soc. '"^ See my " Expression of the Emotions 
Edinburgh," 1866-67, p. 65. in Man and Animals/' 187a, p. 144. 


^ ent, or at least in function. I have seen one man who could 
dtaw the whole ear forward ; other men can draw it upward ; 
another who could draw it backward ; ^ and, from what one of 
these persons told me, it is i)rol)able that most of us, by often 
touching our ears, and thus directing our attention toward 
them, could recover some power of movement by rei)eated 
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 evi- 
dence, of a man who possessed this power, the one which 
might be of use to him. The whole external shell may be con- 
sidered a rudiment, together with the various folds an(* prom- 
inences (helix and anti-helix, tragus and anti -tragus, etc.) 
which in the lower animals strengthen and support ti^e ear 
when erect, without adding much to its weight. Some au- 
thors, however, suppose that the cartilage of the shell serves 
to transmit vibrations to the acoustic nerve ; but Mr. T^ayn- 
bee,29 after collecting all the known evidence on this head, con- 
cludes 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 wuth those of man, ay 
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 satis- 
fied 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 powder 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 powder 
of using their wings for flight. The inability to move the ears 
in man and several apes is, however, partly compensated by 
the freedom with which they can move the head in a horizon- 

38 Canestrini quotes Hyrtl. ("Annuario me that he had lately been experimenting on 

della Soc. dei NaUiralisti," Modena, 1867, p. the function of the shell of the ear, and has 

97) to the same effect. come to nearly the same conclusion as that 

19 "The Diseases of the Ear," by J. given here. 
Toynbee, F.R.S., i86n, p. 12. A distin- ■<" Prof A. Macallister, "Annals and 

flushed physiologist, Prof. Preyer in,forjn.<; Mag. o^Nat. History," vol. vii., 1871, p. 34^ 

CHAP. 1.3 



tal plane, so as to catch sounds from all directions. It has 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. Preyer, it is not rarely absent in the negro. 

The celebrated sculptor, Mr. Woolner, informs me of one 
little peculiarity in the external ear, which he has often ob- 
served both in men and women, and of v/hich he perceived the 
full significance. His attention was first called to the subject 
while at work on his figure of Puck, to which he had given 
pointed ears. He was thus led to examine the ears of various 
monkeys, and subsequently more carefully those of man. 
The peculiarity consists in a little blunt point, projecting from 
the inwardly folded margin, or hehx. When present, it is 
developed at birth, and, according to Prof. Ludwig Meyer, 
more frequently in man than in woman. Mr. Woolner made 
an exact model of one such case, and sent me the accompany- 
ing drawing. (Fig. 2.) These points 
not only project inward toward the 
centre of the ear, but often a little 
outward from its plane, so as to be 
visible when the head is viewed from 
directly in front or behind. They 
are variable in size, and somewhat in 
position, standing either a little high- 
er or lower ; and they sometimes oc- 
cur on one ear and not on the other. 
They are not confined to mankind, 
for I observed a case in one of the 
spider-monkeys {Ateles beehebutJi) in 
our Zoological Gardens; and Dr. E. Fig. 2. Human Ear, modelled 
Ray Lankester informs me of another ihe pr'Jecting point. °"""* "' 
case in a chimpanzee in the gardens 

at Hamburg. The helix obviously consists of the extreme 
margin of the ear folded inward ; and this folding appears to 
be in some manner connected with the whole external ear be- 
ing permanently pressed backward. In many monkeys, which 
do not stand high in the order, as baboons and some species of 
macacus,^ the upper portion of the ear is slightly pointed, and 
the margin is not at all folded inward ; but if the margin were 

•' Mr. St. George Mlvart, "Elementary Messrs. Murie and Mivart's excellent papef 

Anatomy," 1873, p. 396. in "Transact. Zoolog. Soc.,'* -vol. vii. 1869^ 

'" See also some remarks, and the draw- pp. 6 and 90. 
lag; of ttie ears of the Lemuroidea, in 

32 THE DESCENT OF MAN, (part l 

to be thus folded, a slight point would necessarily project in« 
ward toward the centre, and probably a little outward from 
the plane of the ear: and this 1 believe to be their ori^^ir* 
in many cases. On the other hand. Prof. L. Meyer, in an 
able paper recently published,'*"^ maintains that the whole case 
is one of mere variability ; and that the projections are not real 
ones, but are due to the 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. Nev- 
ertheless, 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, chat 
supposing, in accordance with Prof. Meyer's view, the ear to 
be made perfect by the equal development of the cartilage 
throughout the whole exten^ of the margin, it would have cov- 
ered fully one-third of the whole ear. Two cases have been 
communicated to me— one in North America, and the other in 
England — in which the upper margin is not at all folded in- 
ward, 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 niger, and says that their outlines are closely 
similar. If, in these two cases, the margin had been folded 
inward in the normal manner, an inward projection must have 
been formed. I may add that in two other cases the outline 
still remains somewhat pointed, although the margin of the 
upper part of the ear is normally folded inward — in one of 
them, 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 

" Ueber das Darwin'sche Spitzohr, S4 •' The Expression of the Emotions,*' pt 
Archiv fur Path. AnaU und Phys. 1871, p. 1361 

CHAP. I.) 



seen how diflerent the pointed outHne of the ear is at this pe- 
riod from its adult condition, when it bears a close general re- 
semblance to that of man. It is evident that the folding over 
of the tip of such an ear, unless it changed greatly during its 
further development, would give rise to a point projecting in- 
ward. On the whole, it still seems to 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 Orang. Exact copy of a photograph, showing the form of the 

ear at this early age. 

The nictitating membrane, or third eyelid, with its accessory 
muscles and other structures, is especially well developed in 
birds, and is of much functional importance to them, as it can 
be rapidly drawn across the whole eye- ball. It is found in 
3ome reptiles and amphibians, and in certain fishes, as in 
sharks. It is fairly well developed in the two lower divisions 
of the mammalian series, namely, in the monotremata and m,ar- 
supials, and in some few of the higher mammals, as in the wal- 
rus. But in man, the quadrumana, and most other mammals, 
it exists, as is admitted by all anatomists, as a mere rudiment, 
called the semilunar fold.""^ 

•* Miiller's "Elements of Physiology," *' Great Artists and Anatomists," p. 106. 

Eng. translat., 1842. vol. ii. p. 11 17. Owen, This rudiment apparently is somewhat 

"Anatomy of Vertebrates," vol. iii. p. 260 ; larger in Negroes and Australians than in 

ibid, on the Walrus, " Proc. Zoolog. Soc. " Europeans, see Carl Vogt. ** Lectures 09 

November 8, 1654. See also R. Knox. Man,'' Eng. translat. p. 139, 

54 THE DESCEl^T OF AfAI^, ^ari ^ 

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 carnivova, in finding their 
prey ; to others, again, as the wild boar, for both ])urposcs 
combined. But the sense of smell is of extremely slight ser- 
vice, if any, even to the dark-colored races of men, in whom it 
s much more highly developed than in the white and civilized 
races.'^ Nevertheless it does not warn them of danger, nor 
guide them to their food : nor does it prevent the 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 attended to the subject. Those who believe in the princi- 
ple 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 continu- 
ally used. In those animals which have this sense highly de- 
veloped, such as dogs and horses, the recollection of persons 
and of places is strongly associated with their odor ; and we 
can thus perhaps understand how it is, as Dr. Maudsley has 
truly remarked,^ that the sense of smell in man '* is singularly 
effective in recalHng vividly the ideas and images of forgotten 
scenes and places." 

Man differs conspicuously from all the other Primates in be- 
ing almost naked. But a few short straggling hairs are found 
over the greater part of the body in the man, and fine down on 
that of the woman. The different races differ much in hairi- 
ness ; and in the individuals of the same race the hairs are 
highly variable, not only in abundance, but likewise in posi- 
tion ; thus in some Europeans the shoulders are quite naked, 
while in others they bear thick tufts of hair.^s There can be 

>6 The account given by Humboldt of the body. T have, therefore, spoken in the text 

power of smell possessed by the natives of of the dark-colored races having a finer sense 

South America is well known, and has been of smell than the white races. See his paper, 

confirmed by others. M. Houzeau ("iltudes " Medico-Chirurgical Transactions," Lon- 

sur ies Facultes Mentales," etc., torn, i., don, vol. hii.. 1870, p. 276. 

V872, p. 91) asserts that he repeatedly made ^^ "The Physiolosjy and Pathology of 

experiments, and proved that Negroes and Mind," 2d edit., 1868, p. 134. 

Indians could recognize persons m the dark '* E.schricht, Ueber die Richtung der 

by their odor. Dr. W. Ogle has made some Haare am menschlichen Korper, " Miiller'g 

curious observations on the connection be- Archiv fiir Anat. und I'hys." 1837, s. 47. 1 

tween the power of smell and the coloring shall often have to refer to this very curious 

matter of the mucous membrane of the paper. 
•Ifactory region, as well as of the skin of the 


little doubt that the hairs thus scattered over the body are the 
rudiments of the uniform hairy coat of the lower anima s. This 
view is rendered all the more probable, as it is known that fine, 
short, and pale-colored hairs on the limbs and other parts of 
the body occasionally become developed into *' thick-set, long, 
and rather coarse, dark hairs," when abnormally nourished 
near old-standing inflamed surfaces.^ 

I am informed by Sir James Paget that often several mem- 
bers of a family have a iQ\f hairs in their eyebrows much 
longer than the others; so that even this shght peculiarity 
seems to be inherited. These hairs, too, seem to have their 
representatives ; for in the chimpanzee, and in certain species 
of Macacus, there are scattered hairs of considerable length 
rising from the naked skin above the eyes, and corresponding 
to our eyebrows ; similar long hairs project from the hairy cov- 
ering of the superciliary ridges in some baboons. 

The fine wool-like hair, or so-called lanugo, with which the 
human foetus during the sixth month is thickly covered, offers 
a more curious ca3e. It is first developed, during the fifth 
month, on the eyebrows and face, and especially round the 
mouth, where it is much longer than that on the head. A mus- 
tache of this kind was observed by Eschricht^^ on a female 
foetus ; but this is not so surprising a circumstance as it may at 
first appear, for the two '^exes generally resemble each other in 
all external characters daring 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 va- 
riability The whole surface, including even the forehead and 
ears, is thus thickly clothed ; but it is a significant fact that the 
palms of the hands and the soles of the feet are quite naked, like 
the inferior surfaces of all four extremities in most of the lower 
animals. As this can hardly be an accidental coincidence, the 
woolly covering of the foetus probably represents the first per- 
manent coat of hair in those mammals which are born hairy. 
Three or four cases have been recorded of persons born with 
their whole bodies and faces thickly covered with fine, long 
hairs ; and this strange condition is strongly inherited, and is 
correlated with an abnormal condition of the teeth. ^ Prof. 
Alex. Brandt informs me that he has compared the hair from the 

*• Paget, **• Lectures on Surgical Paihol- Prof. Alex. Brandt has recently sent me an 

Igy," 1853, vol. i. p. 7c. additional case of a father and son, bom U| 

•* Eschricht. ibid., s. 40, 47. Russia, with these pco^iliarities. I have I©" 

*' See my "Variation of Animals and ceived drawings of both from Pari$< 
rbn^s under Domestication," vpl, ii. p. 327- 

^G 711 h DESCENT OF AfAAT. |pakt I. 

face of a man thus characterized, aged thirty-five, with the 
lanugo of a foetus, and finds it quite similar in texture; there- 
fore, as he remarks, the case may be attril)uted to an arrest o! 
development in the hair, together with its continued growth. 
Many delicate children, as I have been assured by a surgeon to 
a hospital for children, have their backs covered by rather long 
silky hairs ; and such cases probably come under the same head. 

It appears as if the posterior molar or wisdom-teeth were 
tending to become rudimentary in the more civilized races of 
man. These teeth are rather smaller than the other molars, as 
is Hkewise 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 de- 
nied by some eminent dentists. They are also much more liable 
to vary, both in structure and in the period of their develop- 
ment, than the other teeth. '^^ In the Melanian races, on the 
other hand, the wisdom-teeth are usually furnished with three 
separate fangs, and are generally sound ; they also differ from 
the other molars in size, less than in the Caucasian races. ^ 
Prof. Schaaffhausen accounts for this difference between the 
races by ** the posterior dental portion of the jaw being always 
shortened '* in those that are civilized,''^ and this shortening 
may, I presume, be attributed to civilized men habitually feed- 
ing 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 ap- 
pendage of the caecum. The caecum is a branch or diverticu* 
ium 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 

*' Dr. Webb, "Teeth in Man and the *' Pro£ Mantegazza writes to me from 

Anthropoid Apes," as quoted by Dr. C. Florence, that he has lately been studying 

Carter Blake in "Anthropological Review," the last molar teeth in the different races of 

July, 1867, p. 299. man, and has come to the same conclusion 

** Owen, " Anatomy of Vertebrates," vol. as that given in my text, viz., that in the 

ill. pp. 320, 321, and 325. higher or civilized races they are on the road 

♦♦ " On the Primitive Form of the Skull," toward atrophy or elimination. 

Eng. translat. in " A jithropological Review," ** Owen, " Anatomy of Vertebrates," vg|» 

Oct« 1868, ^ 436. iii. pp. 416, 434, 441. 


tapering point, and is sometimes constricted in pares. It apr 
pears as if, in consequence of changed diet or habits, the cae» 
cum had become much shortened in various animals, the ver- 
miform 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 some- 
times 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. Not only is it useless, but it is sometimes the 
cause of death, of which fact I have lately heard two instances. 
This is due to small hard bodies, such as seeds, entering the 
passage and causing inflammation.'^ 

In some of the lower Quadrumana, in the Lemuridae and 
Carnivora, as well as in many marsupials, there is a passage 
near the lower end of the humerus, called the supra condyloid 
foramen, 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. Struth- 
ers,'*'-' who has closely attended to the subject, has now shown 
that this pecuharity is sometimes inherited, as it has occurred 
in a father, and in no less than four out of his seven children. 
When present, the great nerve invariably passes through it; 
and this clearly indicates that it is the homologue and rudiment 
of the supra-condyloid foramen of the lower animals. Prof. 
Turner estimates, as he informs me, that it occurs in about one 
per cent, of recent skeletons. But if the occasional develop- 
ment of this structure in man is, as seems probable, due to re- 
version, it is a return to a very ancient state of things, because 
in the higher Quadrumana it is absent. 

*' "Annuario dclla Soc. d. Nat.," Mo- and another important paper, ibid., Jan. 24, 

«, 1867, p 94. 1863, p. 83. Dr. Knox, as I am informed, 

♦° M. C. Martins (*'De I'Unit^ Orga- was the first anatomist who drew attention,'' in "Revue des Deux Moniies," to this peculiar structure in man; see his 

June 15, 1862, p. 16), and Hacl<d (" Gen- "Great Artists and Anatomists," p. 6^ 

erelle Morphologic," B. ii s. 278), have both See also an important memoir on this 

remarked on the singular tact f'f this rudi- process by Dr. Gruher, in the " Bulletin do 

ment sometimes causing death. I'Acad. Imp. de St. Fetersb«urg, torn, xii^ 

4" With respect to inheritance, see Dr. 1867, p. 448. 
Stnithers in the " Lancet," Feb. 15, 1873, 

38 THE DESCENT OF MAM. [part i 

There is another foramen or i)erforation in the humerus, 
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 ani- 
mals. It is remarkable that this perforation seems to have been 
])resent 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 ' Cime- 
tit^re du Sud,' at Paris; and in the Grotto of Orrony, the con- 
tents of which are referred to the Bronze period, as many as 
eight humeri out of thirty-two were perforated ; but this ex- 
traordinary proportion, he thinks, might be due to the cavern 
having been a sort of * family vault.' Again, M. Dupont 
found thirty per cent, of perforated bones in the caves of the 
Valley of the Lesse, belonging to the Reindeer period; whilst 
M. Leguay, in a sort of dolmen at Argenteuil, observed twenty- 
ftve per cent, to be perforated ; and M. Pruner-Bey found twenty- 
six per cent, in the same condition in bones from Vaureal. Nor 
should it be left unnoticed that M. Pruner-Bey states that this 
condition is common in Guanche skeletons." It is an inter- 
esting 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 ex- 
tremities, as may be seen in the drawing (Fig. i) 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 ver- 
tebrae, all anchylosed together : and these are in a rudlmen- 

*o Mr. St. George Mivart, "Transact "' Quatrefages has lately collected the 

Phil. Soc," 1867, p. 310. evidence on this subject. "Revue des 

*' " On the Caves of Gibraltar," "Trans- Cours Scientifiques," 1867-68, p. 625. in 

act. Internat. Congress of Prehist. Arch." 1840 Fleischmann exhibited a human fcetus 

Third Session, 1869, p. 159. I'rof. Wynian bearing a free tail, which, as is not always 

has lately shown (Fourth Annual Report, the case, included vertebral bodies ; and 

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

perforation is present in thirty-one per cent, many anatomists present at the meeting of 

of some human remains from ancient mounds naturalists at Erlangen (see Marshall ip 

m the Western United States, and in Florida. Niederlandischen Archiv fiir 2oologie, Yi<sf 

It frequently occurs in the negro. cember, 1871). 


tary condition, for they consist, with the exception of the basal 
one, of the centrum alone. ^ They are furnished with some 
small muscles, one of which, as I am informed by Prof Turner, 
has been expressly described by Theile as a rudimentary repe- 
tion of the extensor of the tail, a muscle which is so largely de- 
veloped in many mammals. 

The spinal cord in man extends only as far downward as the 
last dorsal or first lumbar vertebra ; but a thread-like structure 
(the filum tc7-7mnale) 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, 
^ut the lower part apparently consists merely of the//^ mater, 
or vascular investing membrane. Even in this case the os 
coccyx may be said to possess a vestige of so important a struct- 
ure as the spinal cord, though no longer enclosed within a bony 
canal. The following fact, for which I am also indebted to 
Prof. Turner, shows how closely the os coccyx corresponds with 
the true tail in the lower animals : Luschka has recently dis- 
covered 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 

The reproductive system offers various rudimentary struct- 
ures ; but these differ in one important respect from the fore- 
going 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 show 
that their presence generally depends merely on inheritance, 
that is, on parts acquired by one sex having been partially 
transmitted to the other. I will in this place only give some 
instances of such rudiments. 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 

••Owen, "On the Natiure of Limbs," 1849, p. 114* 

40 77//? DESCENT OF MAN", tPArp » 

in the two sexes is likewise shown by their occasional sympa- 
thetic enlargement in both during an attack of the measles. 
The vesicula prostatica^ which has been observed in many 
male mammals, is now universally acknowledged to be the 
homologue of the female uterus, together with the connected 
passage. It is impossible to read Leuckart's able description 
of this organ, and his reasoning, without admitting the justness 
of his conclusion. This is especially clear in the case of those 
mammals in which the true female uterus bifurcates, for in the 
males of these the vesicula likewise bifurcates.^* Some other 
rudimentary structures belonging to the reproductive system 
might have been here adduced.^ 

The bearing of the three great classes of facts now given is 
unmistakable. But it would be superfluous fully to recapitulate 
the line of argument given in detail in my " Origin of Species." 
The homological construction of the whole frame in the mem- 
bers of the same class is intelligible, if we admit their descent 
from a common progenitor, together with their subsequent 
adaptation to diversified conditions. On any other view, 
the similarity of pattern between the hand of a man or monkey, 
the foot of a horse, the flipper of a seal, the wing of a bat, etc., 
is utterly inexplicable.^ It is no scientific explanation to assert 
that they have all been formed on the same ideal plan. With 
respect to development, we can clearly understand, on the 
principle of variations supervening at a rather late embryonic 
period, and being inherited at a corresponding period, how it 
is 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 

" Leuckart, in Todd's "Cyclop.of Anat.," me (to use Auguste Comte's words) a mere 

1849-52, vol. iv. p. 1415. In man this organ metaphysical principle, namely, the preser- 

is only from three to six lines in length, but, vation "in its integrity of the mammalian 

like so many other rudimentary parts, it is nature of the animal." In only a few cases 

variable in development as well as in other does he discuss rudiments, and then only 

characters. those parts which are partially rudimentary, 

5* See, on this subject, Owen, "Anatomy such as the little hoofs of the pig and ox, 

of Vertebrates," vol. iii. pp. 675, 676, 706. which do not touch the ground ; these he 

68 Prof Bianconi, in a recently published shows clearly to be of service to the animal, 

work, illustrated by admirable engravinc^s It is unfortunate that he did not consider 

("La Theorie Darwinienne et la Creation such cases as the minute teeth, which never 

dite independante," 1874). endeavors to show cut through the jaw in the ox, or the mammas 

that homological structures, in the above and of male quadrupeds, or the wings of certain 

other cases, can be fully explained oti me- beetles, existing under the soldered wing- 

clianical principles, in accordance with their covers, or the vestiges of the pistil ar.d 

uses. No one has shown so well how ad- stamens in various flowers, and many oil'.er 

mirably such structures arc adapted for such cases. Although I gready admire Pi ofl 

their final purpose ; and this adaptation can, Bianconi' s work, yet the belief now held by 

as I believe, be explained through natural most naturalists seems to me left unshaken, 

selection. In considering the wing of a bat, that homological structures are inexplicable 

he brings forward (p. 218) whai appears to on the principle of mere adaptatKOi. 


marvellous fact that the embryos of a man, dog, seal, bat, rep- 
tile, etc., can at first hardly be distinguished from each other. 
In order to understand the existence of rudimentary organs, we 
have only to suppose that a former progenitor possessed the 
parts in question in a perfect state, and that under changed 
habits of life they became greatly reduced, either from simple 
disuse or through the natural selection of those individuals 
which were least encumbered with a superfluous part, aided by 
the other means previously indicated. 

Thus we can understand how it has come to pass that man 
and all other vertebrate animals have been constructed on the 
same general model, why they pass through the same early 
stages of development, and why they retain certain rudiments 
in common. Consequently we ought frankly to admit their 
community of descent ; to take any other view, is to admit 
that our own structure, and that of all the 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 
geological succession. It is only our natural prejudice, and 
that arrogance which made our forefathers declare that they 
were descended from demi-gods, which leads us to demur to 
this conclusion. But the time will before long come, when it 
will be thought wonderful that naturalists, who were well ac- 
quainted with the comparative structure and development of 
man and other mammals, should have believed that each was 
the work of ^ separate act of creation. 

42 THE DESCENT OF MAN: Ipart f. 




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 varia- 
tion — 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 — Conse- 
quent 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 variabihty. 
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 con- 
fined 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 ab- 
normal courses that it has been found useful for surgical pur- 
poses to calculate from 1,040 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 

' "Investigations in Military and An- 1863, p. 87. On the Sandwich Islanders, 

thropolog. Statistics of American Soldiers," Prof. J. Wyman, "'Observations on Crania, 

by B. A. Gould, 1869, p. 256. Boston, 1868, p. 18. 

' With respect to the " Cranial Forms of ^ "Anatomy of the Arteries," by R. 

the American Aborigines," see Dr. Aitken Quain. Preface, vol. i., 1844. 
Meigs in " Proc. Acad. Nat. Sci.," Philadel- * "Transact. Royal Soc. Edinburgh,* 

phia. May, 1868. On the Australians, see vol, xxiv. pp. 175, 189. 
Huxley, in Lycll's " Antiquity of Man," 


considerable. He adds, that the power of performing the ap- 
propriate movements must have been modified in accordance 
with the several deviations. Mr. J. Wood has recorded 5 the 
occurrence of 295 muscular variations in thirty-six subjects, and 
in another set of the same number no less than 558 variations, 
those occurring on both sides of the body being only reckoned 
as one. In the last set, not one body out of the thirty-six was 
"found totally wanting in departure from the standard descrip- 
tions of the muscular system given in anatomical text-books." 
A single body presented the extraordinary number of twenty-five 
distinct abnormalities. The same muscle sometimes varies in 
many ways: thus Prof. Macalister describes 6 no less than 
twenty distinct variations in the pahneris accessorius. 

The famous old anatomist, Wolff,7 insists that the internal 
viscera are more variable than the external parts: Nulla parti- 
cula est quce 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, etc., as of the human face divine, sounds 
strange in our ears. 

The variability or diversity of the mental faculties in men 
of the same race, not to mention the greater differences between 
the men of distinct races, is so notorious that not a word need 
here be said. So it is with the lower animals. All who have 
had charge of menageries admit this fact, and we see it plainly 
in our dogs and other domestic animals. Brehm especially 
insists that each individual monkey of those which he kept 
tame in Africa had his own peculiar disposition and temper; 
he mentions one baboon remarkable for its high intelligence, 
and the keepers in the Zoological Gardens pointed out to me a 
monkey, belonging to the New World division, equally remark- 
able for intelligence. Rengger, also, insists on the diversity in 
the various mental characters ot 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. 8 

I have elsewhere 9 so fully discussed the subject of Inheritance, 
that I need here add hardly anything. A greater number of 

6 "Proc. Royal Soc," 1867, p. 544 ; also ii., p. 217. 

1868, pp. 483, 524. There is a previous ^ Brehm, "Thierleben," B. i, 9, 58, 87. 

paper, 1866, p. 229. Rengger, "Saugethiere von Paraguay," s. 

8 "Proc. R. Irish Academy," vol. x., 57. 

j868, p. 141. 9 "Variation of Animals and Plants un- 

7 •• Act. Acad. St. Petersburg," 1778, part der Domestication," vol. it. chap. xii. 

44 THE DESCENT OF MAAr, i^part t 

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, 
etc. , are certainly transmitted. With man we see similar facts in 
almost every family; and we now know, through the admirable 
labors of Mr. Galton,^^ that genius, which implies a wonderfully 
complex combination of high faculties, tends to be inherited; 
and, on the other hand, it is too certain that insanity and 
deteriorated mental powers likewise run in families. 

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. Do- 
mesticated animals vary more than those in a state of nature ; 
and this is apparently due to the diversified and changing nat- 
ure 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 in- 
habiting a very wide area, like that of America. We see the 
influence of diversified conditions in the more civilized nations ; 
for the members, belonging to different grades of rank, and 
following different occupations, present a greater range of char- 
acter than do the members of barbarous nations. But the uni- 
formity 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 domes- 
ticated animal ; for his breeding has never long been controlled, 
either by methodical or unconscious selection. No race or 

'0 "Hereditary Genius: an Inquiry into had an oval visage with fine features, and 

its Laws and Consequences," 1869. another was quite Mongolian in breadth and 

1' Mr. Bates remarks f"The Naturahst prominence of cheek, spread of nostrils, and 

on the Amazons," 1863, vol. ii. p. 159), with obliquity of eyes." 

respect to the Indians of the same South " Blumenbach, "Treatises on Anthn^ 

American tribe, " no two of them were at all polog.," Eng. translat., 1865, p. 205. 
similar in the shape of the head ; one man 


body of men has been so completely subjugated by other men, 
as that certain individuals should be preserved, and thus un- 
consciously selected, from somehow 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 grenadiers ; and in this case man obeyed, 
as might have been expected, the law of methodical selection ; 
for it is asserted that many tall men were reared in the villages 
inhabited by the grenadiers and their tall wives. In Sparta, 
also, a form of selection was followed, for it was enacted that 
all children should be 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 spe- 
cies, 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 man- 
ner. This has been proved in such full detail by Godron and 
Quatr^fages that I need here only refer to their works. ^^ Mm- 
strosities, which graduate into slight variations, are likewise so 

•8 Mitford's " History of Greece," vol. i. health and vigor of their children, Th« 

p. 282. It appears also from a passage in Grecian poet, Theognis, who lived 550 B.C., 

Xenophon's "Memorabilia," B. ii. 4 (to clearly saw how important selection, if care- 

which my attention has been called by the fully applied, would be for the improvement 

Rev. J. N. Hoare), that it was a well recog- of mankind. He saw, likewise, that wealth 

nized principle with the Greeks, that men often checks the proper action of B'tual 

ought to select their wives with a view to the selection. He thus writes : 

** With kine and horses, Kumus ! we proceed 
By reasonable rules, and choose a breed 
For profit and increase, at any price ; 
Of a sound stock, without defect or vice. 
But, in the daily matches that we make. 
The piice is everything : for money's sake 
Men marry : women are in marriage given ; 
The churl or ruffian, that in wealth has thriven. 
May match his offspring with the proudest race : 
Thus everything is mix'd, noble and base ! 
If then in outward manner, form, and mind, 
You find us a degraded, motley kind. 
Wonder no more, my friend ! the cause is plain, 
And to lament the consequence is vain." 

— ^The Works of J. Hookham Frere, vol. ii., 1872, p. 334, 

M Godron, " De I'Espice," 1859, torn. ii. pology, given in the *' Revue des Couit 
Hvre 3. Quatrefages, " Unite de I'Esp^ce Scientifiques," 1866-68. 
Humaine," 1861. Also Lectures on Anthro- 

4ft THE DE<iCEMT OP MA^. [PAftT t 

similar in man and the lower animals, that the same classifica- 
tion and the same terms can Ixj used for both, as has been 
shown by Isidore Geoffroy St.-Hilaire.'^' In my work on the 
variation of domestic animals, I have attempted to arrange in a 
rude fashion the laws of variation under the following heads: 
The direct and definite action of changed conditions, as ex- 
hibited by all or nearly all the individuals of the same species, 
varying in the same manner under the same circumstances. 
The effects of the long-continued use or disuse of parts. The 
cohesion of homologous parts. The variability of multiple 
parts. Compensation of growth ; but of this law I have found 
no good instance in the case of man. The effects of the me- 
chanical pressure of one part on another ; as of the pelvis on 
the cranium of the infant in the womb. Arrests of develop- 
ment, 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 
conditions 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 re- 
sult. But I have failed to obtain clear evidence in favor of 
this conclusion ; and valid reasons may be urged on the other 
side, at least as far as the innumerable structures are concerned, 
which are adapted for special ends. There can, however, be 
no doubt that changed conditions induce an almost indefinite 
amount of fluctuating variability, by which the whole organi- 
zation is rendered in some degree plastic. 

In the United States, above one million soldiers, who served 
in the late war, were measured, and the States in which they 
were born and reared were recorded.^' From this astonishing 

'• "Hist. G^ Part, des Anomalies de published a valuable essay "De I'lnflue^icc 

i'Organisation," in three volumes, torn, i., des Milieux," etc. He lays much stress, in 

1832. the case of plants, on the nature of the soiL 

'• I have fully discussed these laws in '^ "Investigations in Military and An- 

my " Variation of Animals and Plants un- throp. Statistics," etc., 1869, by B. A. Gould* 

der Domestication," vol. ii. chaps, xxii. and pp. 93, 107, 126, 131, 134, 
Xjriii. M. J. P. Durand has lately (1868) 


number of observations it is proved that local influences of 
some kind act directly on stature ; and we further learn that 
** the State where the physical growth has in great measure 
taken place, and the State of birth, which indicates the an- 
cestry, 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 shown '* by the great difference be- 
tween the statures of soldiers and sailors at the ages of seven= 
teen and eighteen years." Mr. B. A. Gould endeavored to 
ascertain the nature of the influences which thus act on stature ; 
but he arrived only at negative results, namely, that they did 
not relate to climate, the elevation of the land, soil, nor even 
** 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 com- 
pare the differences in stature between the Polynesian chiefs and 
the lower orders within the same islands, or between the in- 
habitants 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 sub- 
sistence are very different, it ?s scarcely possible to avoid the 
conclusion that better food and greater comfort do influence 
stature. But the preceding statements show hov/ 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 occupations have a deteriorating influence on height ; 
and he infers that the result is to a certain extent inherited, as 
is likewise the case in the United States. Dr. Beddoe further 
believes that wherever a *' race attains its maximum of physical 
development, it rises highest in energy and moral vigor." ^^ 

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

*8 For the Polynesians, see Prichard's allied Hindoos inhabiting the Upper Ganges 

"Physical Hist, of Mankind," vol. v., 1847, and Bengal ; see Elphinstone's "History ol 

pp. 145,283. AlsoGodron, "Del'Espfece," India," vol. i. p. 324. 

torn. ii. p. 289. There is also a remarkable " " Memoirs, Anthropolog. Soc.,"voL UIm 

4ifference in appeairance between the closely 1867-69, pp. 561, 565, 567. 

49 THE DESCENT OP MAN, (part l 

-one.® It was formerly thought that the color of the skin and thft 
character of the hair were determined by light or heat; and 
although it can hardly be denied that some effect is thus [)ro- 
duced, almost all observers no\v 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 mankind. With our domestic animals there 
are grounds for believing that cold and damp directly affect the 
growth of the hair ; but I have not met with any evidence on 
this head in the case of man. 

Effects of the increased Use and Disuse of Parts. — It is well 
known that use strengthens the muscles in the individual, and 
complete disuse, or the destruction of the proper nerve, weakens 
them. When the eye is destroyed, the optic nerve often be- 
comes 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 in- 
crease 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 ; while their arms were shorter 
by 1.09 of an inch, and therefore, out of proportion, shorter 
in relation to their lesser height. This shortness of the arms 
is apparently due to their greater use, and is an unexpected 
result : but sailors chiefly use their arms in pulling, and not 
in supporting weights. With sailors, the girth of the neck and 
the depth of the instep are greater, while 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. Rengger '^ attrib- 
utes the thin legs and thick anns of the Payaguas Indians to 
successive generations having passed nearly their whole lives in 

9" Dr. Brakenridge, "Theory of Diathe- 300. Dr. Jaeger, "Ueber das Langen- 

eis," " Medical Times," June 19 and July wachsthum der Knochen," " Jenaischen 

J7, i860. Zeitschrift," B. v. Heft i. 

** I nave given authorities for these sev- " " Investigations," etc By B. A. Gould, 

eral statements in my "Variation of Ani- 1869, p. 288, 

nals under Domestjcationt" YOL u. pp. 297- '' "Saugcthicw \<m ?ayafuay," 1830, s.* 


canoes, with their lower extremities motionless. Other writ- 
ers have come to a similar conclusion in analogous cases. Ac- 
cording to Cranz,^ who lived for a long time with the Esqui- 
maux, ** the natives believe that ingenuity and dexterity in 
seal-catching (their highest art and virtue) is hereditary ; there 
is really something in it, for the son of a celebrated seal- 
catcher will distinguish himself, though he lost his father in 
childhood." But in this case it is mental aptitude, quite as 
much as bodily structure, which appears to be inherited. It 
is asserted that the hands of English laborers are at birth larger 
than those of the gentry.^ From the correlation whir-^ exists, 
at least in some cases,'-* between the development of the ex- 
tremities and of the jaws, it is possible that in those classes 
which do not labor much with their hands and feet, the jaws 
would be reduced in size from this cause. That they are gen- 
erally smaller in refined and civihzed men than in hard-work- 
ing men or savages, is certain. But with savages, as Mr. Her- 
bert Spencer '^ has remarked, the greater use of the jaws in 
ciiewing coarse, uncooked food, would act in a direct manner 
on the masticatory muscles, and on the bones to which they 
ai2 attached. In infants, long before birth, the skin on the 
soles of the feet is thicker than on any other part of the 
body ; ^ and it can hardly be doubted that this is due to the 
inherited effects of pressure during a long series of generations. 
It is familiar to everyone that watchmakers and engravers 
are liable to be short-sighted, while men living much out of 
doors, and especially savages, are generally long-sighted.^ 
Short-sight and long-sight certainly tend to be inherited.^ The 
inferiority of Europeans, in comparison with savages, in eye- 
sight and in the other senses, is no doubt the accumulated and 
transmitted effect of lessened use during many generations ; for 
Rengger ^^ states that he has repeatedly observed Europeans, 

'* " History of Greenland," Eng. trans- being ''restricted to the length of the vessei 

lat., 1767, vol. i. p. 230. and the height of the masts." 

as "Intermarriage." By Alex. Walker, 3" "The Variation of Animals under 

1838, p. 377. Domestication," vol. i. p. 8. 

28 "The Variation of Animals under '' " Saugethiere von Paraguay," s. 8, 10. 

Domestication," vol. i. p. 173. I have had good opportunities for observing 

37 «' Principles of Biology," vol. i. p. 455. the extraordinary power of eyesight in the 

'^ Paget, " Lectures on Surgical Pathol- Fuegians. See also Lawrence (" Lectures 

ogy," vol. ii., 1853, p. 209. on Physiology," etc., 1822, p. 404) on this 

59 It is a singular and unexpected fact same subject. M. Giraud-Teulon has re- 

that sailors are inferior to landsmen in their cently collected (" Revue des Cours Scienti- 

mean distance of distinct vision. Dr. B. A. fiques," 1870, p. 625) a large and valuable 

(Gould " Sanitary Memoirs of the War of body of evidence proving that the cause of 

the Rebellion," 1869, p. 530) has proved short-sight '*<^«/ le travail assidu, tU 

this to be the case ; and he accounts for it prks." 

\n the ordinary ranee of vision in sailors _ 


50 77//'; Di:SCEA'7' OF MA!^. [part l 

who had l^ecn brought up and spent their whole lives with the 
wild Indians, wlio nevertheless did notecpial them in theshar[)- 
ness of their senses. The same naturalist ol)serves that the 
cavities in the skull for the recci)tion of the several sense- 
organs are larger in tlie American aborigines than in Europeans ; 
and this probably indicates a corresponding difference in the 
dimensions of the organs themselves. Blumenbach has also re- 
marked on the large size of the nasal cavities in the skulls of 
the American aborigines, and connects this fact wirh their re- 
markably acute power of smell. The Mongolians of the plains 
of Northern Asia, according to Pallas, have wonderfully perfect 
senses; and Prichard believes that the great breadth of their 
skulls across the zygomas follows from their highly developed 

The Quechua Indians inhabit the lofty plateaux of Peru ; 
and Alcide d'Orbigny states^ that, from continually breathing 
a highly larefied atmosphere, they have acquired chests and 
lungs of extraordinary dimensions. The cells, also, of the 
lungs are larger and more numerous than in Europeans. These 
observations have been doubted ; but Mr. D. Forbes carefully 
measured many Aymaras, an allied race, living at the height ol 
between ten thousand and fifteen thousand feet ; and he in- 
forms me ^ 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 one thousand, and the other measurements are 
reduced to this standard. It is here seen that the extended 
arms of the Aymaras are shorter than those of Europeans, and 
much shorter than those of Negroes. The legs are likewise 
shorter ; and they present this remarkable peculiarity, that in 
every Aymara measured, the femur is actually shorter than the 
tibia. On an average, the length of the femur to that of the 
tibia is as2ii to 252; while in two Europeans, measured at the 
same time, the femora to the tibiae were as 244 to 230 ; and in 
three Negroes as 258 to 241. The humerus is likewise shorter 
relatively to the forearm. This shortening of that part of the 
limb which is nearest to the body appears to be, as suggested 
to me by Mr. Forbes, a case of compensation in relation with 
the greatly increased length of the trunk. The Aymaras pn;- 

^2 Prichard, "Phys. Hist, of Mankind," the Phys. History of Mankind," vot- v. p. 

en the authority of Bhimenbach, vol. i., 1851, 463. 

p. 311; for the statement by Pallas, vol. iv., ** Mr. Forbes's valuable paper is now pub- 

1844, p. 407. lished in the ''Journal of the Ethnolog Soc 

^ Quoted by Prichard, " Researches into of Londooj" new series, vd. ii., 1870, «>. «j^ 


sent some other singular points of structure, for instance, the 
very small projection of the heel. 

These men are so thoroughly acclimatized to their cold and 
lofty abode, that when formerly carried down by the Spaniards 
to the low eastern plains, and when now tempted down by high 
wages to the gold-washings, they suffer a frightful rate of 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 pecuhari- 
ties had all decreased ; and on measurement, their bodies were 
found not to be so much elongated as those of the men on the 
high plateau ; while their femora had become somewhat length- 
ened, as had their tibiae, although in a less degree. The actual 
measurements may be seen by consulting Mr. Forbes's memoir. 
From these observations, there can, I think, be no doubt that 
residence during many generations at a great elevation tends, 
both directly and indirectly, to induce inherited modifications 
in the proportions of the body.^ 

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

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

" Dr. Wilckens (" Landwirthschaft. tainous regions have their frames modr 

Wochenblatt," No. lo, 1869) has lately fied. 

published an interesting essay showing '« " M^moire sur les Microcepkales,'* 

bow domestic animals whKh live in moun- 1867, pp. 50, 125, 169, 171, 184-198. 

$2 THE DESCENT OF MAN". Cpart r 

sinus, or the projection over the eyebrows, is largely developed, 
and the jaws are prognathous to an '* effrayant'' degree; so 
that these idiots somewhat resemble the lower types of man- 
kind. Their intelligence 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 gambolling and jumping about, and making gri- 
maces. They often ascend stairs on all-fours, and are curiously 
fond of climbing up furniture or trees. We are thus reminded 
of the delight shown by almost all boys in climbing trees; and 
this again reminds us how lambs and kids, originally alpine 
animals, delight to frisk on any hillock, however small. Idiots 
also resemble the lower animals in some other respects ; thus 
several cases are recorded of their carefully smelling every 
mouthful of food before eating it. One idiot is described as 
often using his mouth in aid of his hands, while hunting for 
lice. They are often filthy in their habits, and have no sense 
of decency ; and several cases have been published of their 
bodies being remarkably hairy. ^ 

Reversion. — Many of the cases to be here given might havt 
been introduced under the last heading. When a structure is 
arrested in its development, but still continues growing, until 
it closely resembles a corresponding structure in some lower 
and adult member of the same group, it may in one sense be 
considered as a case of reversion. The lower members in a 
group give us some idea how the common progenitor was 
probably constructed ; and it is hardly credible that a complex 
part, arrested at an early phase of embryonic development, 
should go on growing so as ultimately to perform its proper 
function, unless it had acquired such power during some earlier 
state of existence, when the present exceptional or arrested 
structure was normal. The simple brain of a microcephalous 
idiot, in as far as it resembles that of an ape, may in this sense 
be said to offer a case of reversion.^ There are other cases which 

'^ Prof. Laycock sums up the character of ^^ In my " Variation of Animals under 

brute-like idiots by calling them thcroui ; Domestication" (vol. ii. p. 57) I attributed 

" Journal of Mental Science," July. 1863. the not very rare cases of supernumerary 

Dr. Scott ("The Deaf and Dumb," 2d mammae in women to reversion. I was led 

edit., 1870, p. 10) has often ol served the to this as a probable conclusion, by the 

imbecile smelHng their food. See, on this additional mammae being generally placed 

same subject, and on the hairiness of idiots, symmetrically on the breast ; and more espe- 

Dr. Maudsley, " Kody and Mind," 1870, cially from one case, in which a single effi< 

pp. 46-51. Pinel has also given a striking cient mamma occurred in the inguinal region 

case of hairiness in an idiot. cA a woman, the daughter of another womaa 

CHAP, nj 



come more strictly under our present head of reversion. Certain 
structures, regularly occurring in the lower members of the group 
to which man belongs, occasionally make their appearance in 
him, though not found in the normal human embryo ; or, if 
normally present in the human embryo, they become abnormally 
developed, although in a manner which is normal, in the lower 
members of the group. These remarks will be rendered clearer 
by the following illustrations. 

In various mammals the uterus graduates from a double 
organ, with two distinct orifices and two passages, as in the 
marsupials, into a single organ, which is in no way double, 
except from having a slight internal fold, as in the higher apes 
and man. The rodents exhibit a perfect series of gradations 
between these two extreme states. In all mammals the uterus 
is developed from two simple primitive tubes, the inferior 
portions of which form the cornua ; and it is, in the words of 
Dr. Farre, ^' by the coalescence of the two cornua at their lower 
extremities that the body of the uterus is formed in man ; 

with supernumerary mammse. But I now 
find (see, for instance. Prof. Preyer ('* Der 
Kampf um das Dasein," 1859, s. 45) that 
mamma erraticcB occur in other situations, 
as on the back, in the armpit, and on the 
thigh ; the mammae in this latter instance 
having given so much milk that the child 
was thus nourished. The probability that 
the additional mammae 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 informa- 
tion in several cases. It is well known that 
some Lemurs normally have two pairs of 
mammae on the breast. Five cases have 
been recorded of the presence of more than 
a pair of niammss (of course rudimentary) in 
the male sex of mankind ; see "Journal of 
Anat. and Physiology," 1872, p. 56, for a 
case e;iven by Dr. Handyside, in which two 
brothers exhibited this peculiarity ; see also 
a paper by Dr. Bartels in " Reicheri's and 
du Bois-Reymond's Archiv." 1872, p. 304. 
In one of the cases alluded toby Dr. Hartels, 
a man bore five mammae, one being medial 
and placed above the navel ; Meckel von 
Hemsbach thinks that this latter case is 
illustrated by a medial mamma occurring in 
certain Cheiroptera. On the whole we may 
well doubt if additional mammae would ever 
have been developed in both sexes of man- 
kind, had not his early progenitors been 
provided with more than a single pair. 

In the above work (vol. ii. p. 12), I also 
attributed, though with much hesitation, the 
frequent cases of polydactylism in men and 
various animals to reversion. I was partly 
Ned to this through Prof. Owea's statement. 

that some of the Ichthyopterygia possess 
more than five digits, and therefore, as I 
supposed, had retained a primordial con- 
dition ; but Prof. Gegenbaur (*' JeHaischen 
Zeitschrift," B. v. Heft 3, s. 341), disputes 
Owen's conclusion. On the other hand* 
according to the opinion lately advanced by 
Dr. Giinther, on the paddle of Ceratodus, 
which is provided with articulated bony rays 
on both sides of a central chain of bones, 
there seems no great difficulty in admitting 
that six or more digits on one side, or on 
both sides, might reappear through reversion. 
I am informed by Dr. Zouteveen that there 
is a case on record of a man having twenty- 
four fingers and twenty-four toes ! I was 
chiefly led to the conclusion that the presence 
of supernumerary digits might be due to 
reversion from the fact that such digits not 
only are strongly inherited, but, as I then 
believed, had the power of regrowth after 
amputation, like the normal digits of the 
lower vertei>rata. But I have explained in 
the Second Edition of my "Variation under 
Domestication"why I now place litde reliance 
on the recorded cases of such regrowth. 
Nevertheless it deserves notice, inasmuch 
as arrested development and reversion are 
intimately related processes ; thai various 
structures m an embryonic or arrested con- 
dition, such as a cleft palate, bifid uterus, 
etc., are frequently accompanied by poly- 
dactylism. This has been strongly insisted 
on by Meckel and Isidore Geoffroy St- 
Hilaire. But at present it is the safest 
course to give up altogether the idea that 
there is any relation between the develop- 
ment of supernumerary digits and reversion 
to some lowly organized progenitor of 

54 ^-^^^^ DESCENT OF MAN [part l 

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, 
'intil at length they are lost, or, as it were, absorbed into the 
body of the uterus." The angles of the uterus are still pro- 
duced into cornua, even in animals as high up in the scale as the 
lower apes and lemurs. 

Now in women, anomalous cases are not very infrequent, in 
which the mature uterus is furnished with cornua, or is partially 
divided into two organs ; and such cases, according to Owen, 
repeat " the grade of concentrative development," attained by 
certain rodents. Here perhaps we have an instance of a simple 
arrest of embryonic development, with subsequent growth and 
perfect functional development ; for either side of the partially 
double uterus is capable of performing the proper office of 
gestation. In other and rarer cases, two distinct uterine cavities 
are formed, each having its proper orifice and passage.-*^ No 
such stage is passed through during the ordinary development 
of the embryo, and it is difficult to believe, though perhaps not 
impossible, that the two simple, minute, primitive tubes should 
know how (if such an expression may be used) to grow into two 
distinct uteri, each with a well-constructed orifice and passage, 
and each furnished with numerous muscles, nerves, glands, and 
vessels, if they had not formerly passed through a similar course 
cf 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. 

Prof. 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, 

*' See Dr. A. Farre's well-known article bones in several human subjects and in cer- 
in the "Cyclopaedia of Anatomy and Physi- tain apes, he cannot consider this disposition 
ology," vol. v., 1859, P- 642. Owen, " Anat- ot the parts as simply accidental. Another 
omy of Vertebrates," vol. iii., 1868, p. 687. paper on this same anomaly has been pub- 
Professor Turner in "Edinburgh Medical lished by Dr. Saviotti in the " Gazzetta delle 
Journal,"' February, 1S65. Cliniche," Turin, 1871, where he saj^s that 

*" "Annuario della Soc. dei Naturalist! traces of the division may be detected in 

fn Modena," 1867, p. 83. Prof. Canestrini about two per cent, of adult skulls ; he also 

gives extracts on this subject from various remarks that it more frequently occurs in 

authorities. Laurillard remarks that as he prognathous skulls, not of the Aryan race, 

has found a complete similarity in the form, than in others. See also G. Delorenzi oa 

froportions, and connection oi the two malar the same subject, "Tre nuovi casi d' ano* 


normally consists of two portions. This is its condition in tlie 
human foetus when two months old ; and, through arrested 
development, it sometimes remains thus in man when adult, more 
especially in the lower prognathous races. Hence Canestrini 
concludes that some ancient progenitor of man must have liad 
this bone normally divided into two portions, which afterward 
became fused together. In man the frontal bone consists of a 
single piece, but in the embryo, and in children, and in almost 
all the lower 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 brachy- 
cephalic type. Here again he comes to the same conclusion as 
in the analogous case of the malar bones. In this, and other 
instances presently to be given, the cause of ancient races 
approaching the lower animals in certain characters more fre- 
quently than do the modern races, appears to be, that the latter 
stand at a somewhat greater distance in the long line of descent 
from their early semi -human progenitors. 

Various other anomalies in man, more or less analogous to the 
foregoing, have been advanced by different authors, as cases of 
reversion ; but these seem not a little doubtful, for we have to 
descend extremely low in the mammalian series before we find 
such structures normally present.''^ 

In man, the canine teeth are perfectly efficient instruments 
for mastication. But their true canine character, as Owen'^ 
remarks, '' is indicated by the conical form of the crown, which 
terminates in an obtuse point, is convex 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 

malia dell' osso, malare," Torino, 1872. Also, ing its development, is not only a me»ns to 
E. Morselli, " Sopra una rara anomalia dell' an end, but once was an end in itself." This 
osso malare," Modena, 1872. Still more does not seem to me necessarily to hold 
recently Gruber has written a pamphlet on good. Why should not variations occur 
the division of this bone. I ^ive these during an early period of development, hav- 
references because a reviewer, without any ing no relation to reversion ; yet .uch vari- 
grounds or scruples, has thrown doubts on ations might be preserved and accumulated, 
my statem'-nts. if in any way serviceable, for instance, in 
<' A whole series of cases is given by Isid. shortenins and simplifying the course of 
Geoffrey St.-Hilaire, "Hist, des Anoma- development? And again, why should not 
lies," torn. iii. p. 437. A reviewer (" Journal injurious abnormalities, such as atrophied 
of Anat. and Physiology," 1871, p. 366) or hypertrophied parts, which have no re- 
blames me much for not having discussed lation to a former state of existence, oc^Mr at 
the numerous cases, which have been record- an early period, as well as during matunty? 
ed, of various parts arrested in their develop- *2"^\„3(omy of Vertebrates," \mk iit, 
■lent. He says that, according to my theory, i868, p. 323. 
*' every transient condition of an organ, dur- 


Melanian races, especially the Australian. The canine is more 
deeply implanted, and by a stronger fang than the incisors." 
Nevertheless, this tooth no longer serves man as a special weapon 
for tearing his enemies or prey ; it may, therefore, as far as its 
proper function is concerned, be considered as rudimentary. In 
every large collection of human skulls some may be found, as 
Hiickel •'^ observes, with the canine teeth projecting considerably 
beyond the others in the same manner as in the anthropomor- 
phous 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.'" Con- 
sidering how few are the ancient skulls which have been 
examined, compared to recent skulls, it is an interesting fact 
that in at least three cases the canines project largely \ and in 
the Naulette jaw they are spoken of as enormous.'*^ 

Of the anthropomorphous apes the males alone have their 
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 occa- 
sional great development in man is a case of reversion to an 
ape-like progenitor. He who rejects with scorn the belief that 
the shape of his own canines, and their occasional great de- 
velopment in other men, are due to our early forefathers having 
been provided with these formidable weapons, will probably 
reveal, by sneering, the line of his descent. For though he no 
longer intends, nor has the power, to use these teeth as weapons, 
he will unconsciously retract his "snarHng muscles" (thxis 
named by Sir C. Bell),'^^ so as to expose them ready for action, 
like a dog prepared to fight. 

Many muscles are occasionally developed in man, which are 
proper to the Quadrumana or other mammals. Prof. Vlaco- 
vich ^'^ examined forty male subjects, and found a muscle, called 
by him the ischio-pubic, in nineteen of them ; in three others 
there was a ligament which represented this muscle ; and in 
the remaining eighteen no trace of it. In only two out of 

*3 " Generelle Morphologic," 1866, B. ii. p. 295. SchaafFhausen, ibid., 1868, pw 

s. civ. 426. 

<* Carl Vogt's " Lectures on Man." Eng. <• "The Anatomy of Expression," 1844, 

translat., 1864, p. 151. , pp. 110, 131. 

<* C. Carter Blake, on a jaw from La *' Quoted by Prof. Canestrini in dM 

Naulette, " Anthropolog. Review," 1867, "Annuario," ete., 1867, p. 90, 


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 intelhgible ; 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 avast number of muscular variations in man, which 
resemble normal structures in the lower animals. The muscles 
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 claviculcsj* 
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 shown tri 
exist uniformly in the higher and lower apes." I will givt 
only two additional cases ; the acromio-basilar muscle is found 
in all mammals below man, and seems to be correlated with a 
quadrupedal gait,^ and it occurs in about one out of sixty 
human subjects. In the lower extremities Mr. 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 charac- 
teristic of man — are extremely liable to vary, so as to resemble 
the corresponding muscles in the lower animals. ^^ Such resem- 

<*• These papers deserve careful study by in the muscles leading to structures found in 

anyone who desires to learn how frequently animals still lower in the scale, arc numerous 

our muscles vary, and in varying come to re- in the Lemuroidea. 

sombie those of the Quadrumana. The fol- ■" See also Prof. Macalister in " Proc. R. 

iowmg references relate to the few points Irish Academy," vol. x., 1868, p. 124. 

touched on in my text : "Proc. Royal Soc, '" Mr. Champneys in "Journal of Anat. 

vol. xiv., 1865, pp. 379-384; vol. XV., 1866, and Phys.," Nov., 1871, p. 178. 

pp. 241, 242 ; vol. XV., 1867, p. 544; vol. xvi., s' "Journal of Anat. and Phys.," May, 

1868^ p. 524. I may here add that Dr. 1872, p. 421. 

Mune and Mr. St. George Mivart have ^' Prof. Macalister (ibid., p. 121) has tabu- 
shown in their Memoir on the Lemuroidea lated his observations, and finds that muscu- 
(" Transact. Zoolog. Soc," vol. vii.. 1869, p. lar abnormalities are most fraqucnt in the 
96) how extraordinarily variable some of the fore-arms, secondly, in the face, thirdly, IB 
muscles are in these animals, the lowest the foot, etc. 
^embers.of the Primates. Gradations, also, 



blances are either perfect or imperfect ; yet in the latter case 
they are manifestly of a transitional nature. Certain variations 
are more conuiion in man, and others in women, without 
our being able to assign any reason. Mr. Wood, after describ- 
ing numerous variations, makes the following j)regn?nt 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." ^ 

That this unknown factor is reversion to a former state of ex- 
istence may be admitted as in the highest degree probable.^ 
It is quite incredible that a man should through mere accident 
abnormally resemble certain aj)es 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-colored stripes suddenly reappear on the legs and 
shoulders, after an interval of hundreds, or more probably of 
thousands, of generations. 

These various cases of reversion are so closely related to those 
of rudimentary organs given in the first chapter, that 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 mammae 
in the male sex, are always present ; while others, such as the 
supra-condyloid foramen, only occasionally appear, and there- 

*' The Rev. Dr. Haughton, after giving their relations to the same muscle in th« 

i"Proc. R. Irish Academy," June 27, 1864, Quadrumana. 

p. 715) a remarkable case of variation in the °^ Since the first edition of this book ap- 
\i\xma.x\Jiexor poinds long-US, didds: "This peared, Mr. Wood has published another 
remarkable example shows that man may memoir in the "Phil. Transactions," 1870, 
sometimes possess the arrangement of ten- p. 83, on the varieties of the muscles of the 
dons of thumb and fingers characteristic of human neck, shoulder, and chest. He here 
the macaque ; but whether such a case shows how extremely variable these muscles 
should be regarded as a macaque passing are, and how often and how closely the van- 
upward into a man, or a man passing down- ations resemble the normal muscles of the 
ward into a macaque, or as a congenital lower animals. He sums up by remarking . 
freak of nature, I cannot undertake to say." " It will be enough for my purpose if I hav« 
It is satisfactory to hear so capable an anato- succeeded in showing the more iniportant 
mist, and .so embittered an opponent of evolu- forms which, when occurring as varieties in 
tionism, admitting even the possibility of the human subject, tend to exhibit in a suffi- 
either of his first propositions. Prof Mac- ciently marked manner what may be consid- 
alister has also described ("Proc. R. Irish ered as proofs and examples of the Darwinian 
Acad.," vol. X., 1864, p. 138) variations in the principle of reversion, or law of inheritance, 
fitxor />ollicis longus, remarkable from m this department of anatomical science." 


fore might hav^ 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 v/hether the one part 
governs the other, or whether both are governed by some earlier 
developed part. Various monstrosities, as I. Geoffroy repeat- 
edly insists, are thus intimately connected. Homologous 
structures are particularly liable to change together, as we see 
on the opposite sides of the body, and in the upper and lower 
extremities. Meckel long ago 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 color of the skin and of the hair, color and constitu- 
tion, are more or less correlated. ^^ Prof Schaaffhausen first 
drew attention to the relation apparently existing between 
a muscular frame and the strongly pronounced supra-orbita/ 
rMges, 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 shown 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.^ 

Rate of Increase. — Civilized populations have been known 
under favorable conditions, as in the United States, to double 
their numbers in twenty-five years ; and, according to a calcula- 
tion by Euler, this might occur in a little over twelve years. ^^ 
At the former rate the present population of the United States 

»6 The authorities for these several state- in chap, xxiii. vol. ii. of my "Variation of 

ments are given in my " Variation of Ani- Animals and Plants under Domestication." 
mals under Domestication," vol. ii. pp. 320- ^7 See the cvcr-memorable " Essay on the 

335- . . Principle of Population," by the Rev. T. 

•• This whole subject has been discussed Malthus, vol. i. 1826, pp. 6, 517. 


(thirty millions) would in 657 years cover the whole ter- 
raqueous 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 gain- 
ing subsistence, and of living in comfort. We may infer that 
this is the case from what we see, for instance, in the United 
States, where subsistence is easy, and there is plenty of room. 
If such means were suddenly doubled in Great Britain, our 
number would be quickly doubled. With civilized nations 
this primary check acts chiefly by restraining marriages. The 
greater death-rate of infants in the poorest classes is also very 
important ; as well as the greater mortality, from various dis- 
eases, 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 favorable conditions. Emigration also comes in 
aid as a temporary check, but, with the extremely poor classes, 
not to any great extent. 

There is reason to suspect, as Mai thus has remarked, that the 
reproductive power is actually less in barbarous than in civil- 
ized races. We know nothing positively on this head, for with 
savages no census has been taken ; but from the concurrent tes- 
timony 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 suckhng 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 nutri- 
tious food as civilized men, would be actually less prolific. I 
have shown in a former work,^ that all our domesticated quad- 
rupeds 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 sup- 
plied 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 civilized men, who in one sense are highly domes- 
ticated, would be more prolific than wild men. It is also 
probable that the increased fertility of civilized nations would 
become, as with our domestic animals, an inherited char- 

•• ** Variation of Animals and Plants under Domestication,'* vo2. iL pp. iii-ilj, 


acter : it is at least known that with mankind a tendency to 
produce twins runs in families.^ 

Notwithstanding that savages appear to be less prolific than 
civihzed people, they would no doubt rapidly increase if their 
numbers were not by some means rigidly kept down. The 
Santali, or hill-tribes of India, have recently afforded a good 
illustration of this fact ; for, as shown by Mr. Hunter,^ they 
have increased at an extraordinary rate since vaccination has 
been introduced, other pestilences mitigated, and war sternly 
repressed. This increase, however, would not have been possi- 
ble 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 earliest possible age. The young men are often required to 
show that they can support a wife ; and they generally have first 
to earn the price with which to purchase her from her parents. 
With savages the difficulty of obtaining subsistence occasionally 
limits their number in a much more direct manner than with 
civihzed 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 perio- 
dical, depending chiefly on extreme seasons, all tribes must 
fluctuate in number. They cannot steadily and regularly in- 
crease, as there is no artificial increase in the supply of ^ood. 
Savages, when hard pressed, encroach on each other's ter- 
ritories, and war is the result ; but they are indeed almost 
always at war with their neighbors. They are liable to many 
accidents on land and water in their search for food ; and in 
some countries they suffer much from the larger beasts of prey. 
Even in India, districts have been depopulated by the ravages 
of tigers. 

Malthus has discussed these several checks, but he does not 
Jay 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 

•9 Mr. Sedgwick, "British and Foreign «o "The Annals of Rural Bengal," by W. 
MedicQ-Chirurg. Review," July, 1863, p. 170. W. Hunter, 1868, p. 259. 


have prevailed, as Mr. M'T.cnnan ^"^ has shown, on a still more 
extensive scale. These i)ractices appear to have originated in 
savages recognizing 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 fol- 
low from failing means of subsistence ; though there is reason 
to believe that in some cases (as in Japan) it has been inten- 
tionally encouraged as a means of keeping down the popula- 

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 progeni- 
tors would not have practised infanticide or polyandry ; for 
the instincts of the lower animals are never so perverted ^^ as to 
lead them regularly to destroy their own offspring, or to be quite 
devoid of jealousy. There would have been no prudential re- 
straint 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 pre- 
cise nature of these checks were, we cannot say, any more than 
with most other animals. We know that horses and cattle, 
which are not extremely prolific animals, when first turned 
loose in South America, increased at an enormous rate. The 
elephant, the slowest breeder of all known animals, would in a 
few thousand years stock the whole world. The increase of 
every species of monkey must be checked by some means ; but 
not, as Brehm remarks, by the attacks of beasts of prey. No one 
will assume that the actual power of reproduction in the wild 
horses and cattle of 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 

•■ "Primitive Marriage," 1865. and to introduce as a scientific hypothesis 
•^ A writer in the "Spectator" (March the doctrine that man's gain oi knoivledge 
12, 1871, p. 320) comments as follows on this was the cause of a temporary but long- 
passage : "Mr. Darwin finds himself com- enduring moral deterioration, as indicated 
pelled to reintroduce a new doctrine of the by the many foul customs, especially as to 
tall of man. He shows that the instincts of marriage, of savage tribes. What does the 
the higher animals are far nobler than the Jewish tradition of the moral degeneration 
habits of savage races of men, and he finds of man througlj his snatching at a know!- 
himself, therefore, compelled to re-introduce edge forbidden him by his highest instinct 
—in a form of the substantial orthodoxy of assert beyond this ? " 
which he appears to be quite unconscioiis— 


different circumstances ; periodical dearths, depending on un- 
fevorable seasons, being probably the most important of all. 
So it will have been with the early progenitors of man. 

Natural Selection. — We have now seen that man is 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 lower 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 cli- 
mates, 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, occa- 
sionally have been exposed to a struggle for existence, and con- 
sequently to the rigid law of natural selection. Beneficial varia- 
tions 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 differ- 
ences. We know, for instance, that the muscles of our hands 
and feet, which determine our powers of movement, are liable, 
like those of the lower animals,^^ to incessant variability. If 
then the progenitors of man inhabiting any district, especially 
one undergoing some change in its conditions, were divided 
into two equal bodies, the one-half which included all the indi- 
viduals 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 than any other highly organized form, and 
all others have yielded before him. He manifestly owes this 

•' See some good remarks to this efTect Zoolog. Soc.,"vol. vii.,i86g, pp. ^6-98) say : 

by W. Stanley Jcvons, "A Deduction from " Some muscles are so irregular m their dis- 

Darwin's Theory," " Nature," 1869, p. 231. tribution that they cannot be well classed in 

'• Latham, " Man and his Migrations," any of the above groups." These muscles 

1851, p. 135, differ even on the opposite sides of the same 

•* Messrs Murie and Mivart in their individual, 
•* Anatomy of the Lemuroidea" ("Transact. 

64 THB Descent of man, ipart t 

immense superiority to his intellectual faculties, to his social 
habits, which lead him to aid and defend his fellows, and to 
his corporeal structure. The supreme importance of these char- 
acters has been i)roved 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 
miainly depended. As Mr. Chauncey Wright remarks,^^ " a 
psychological analysis of the faculty of language shows 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, etc., 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 neighboring fertile islands. 
He has discovered the art of making fire, by which hard and 
stringy roots can be rendered digestible, and poisonous roots 
or herbs innocuous. This discovery of fire, probably the 
greatest ever made by man, excepting language, dates from be- 
fore the dawn of history. These several inventions, by which 
man in the rudest state has b'^come so pre-eminent, are the di- 
rect results of the development of his powers of observation, 
memory, curiosity, imagination, and reason. I cannot, there- 
fore, understand how it is that Mr. Wallace ^^ maintains that 
** natural selection could only have endowed the savage with a 
brain a Httle 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 

•* Limits of Natural Selection, "North "The Origin of Human Races deduced 

American Review," Oct., 1870, p. 295. from the Theory of Natural Selection," orig- 

'^ "Quarterly Review," April, 1869, p. inally published in the "Anthropologic^ 

392. This subject is more fully discussed in Review," May, 1864, p. clviiL I cannot 

Mr. Wallace's " Contributions to the Theory here resist quoting a most just remark by 

of Natural Selection," 1870, in which all the Sir J. Lubbock {" Prehistoric Times," 1865, 

essays referred to in this work are repub- p. 479) in reference to this paper, namely, 

lished. The "Essay on Man" has been that Mr. Wallace, "with characteristic un- 

ably criticised by Prof. Ciaparide, one of selfishness, ascribes it {i.e., the idea of nat- 

the most distinguished zoologists in Europe, ural selection) unreservedly to Mr. Darwm, 

in an article published in the " Kiblioth^que although, as is well known, he struck out th* 

Universellc," June, 1870. The remark idea independently, and publishec* it^ O^ougb 

quoted in my text will surprise everyone who not with the same elaboration, a» ^e sam^ 

has read Mr. Wallace's celebrated paper on time." 


Stone with as true an aim as a Fuegian in defending himself, or 
in kilHng 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. School- 
craft, ^ remarks, the shaping fragments of stone into knives, 
lances, or arrow-heads shows '^extraordinary ability and long 
practice." This is to a great extent proved by the fact that 
primeval men practised a division of labor ; 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. Ar- 
chaeologists are convinced that an enormous interval of time 
elapsed before our ancestors thought of grinding chipped flints 
into smooth tools. One can hardly doubt that a man-like 
animal who possessed a hand and arm sufficiently perfect to 
throw a stone with precision, or to form a flint into a rude tool, 
could, with sufficient practice, as far as mechanical skill alone 
is concerned, make almost anything which a civilized man can 
make. The structure of the hand in this respect may be com- 
pared 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 be- 
come adapted through the inherited effects of use for the utter- 
ance of articulate language. 

Turning now to the nearest allies of men, and therefore to 
the best representatives of our early progenitors, we find that 
the hands of the Quadrumana are constructed on the same gen- 
eral pattern as our own, but are far less perfectly adapted for 
diversified uses. Their hands do not serve for locomotion so 
well as the feet of a dog ; as may be seen in such monkeys as 
the chimpanzee and orang, which walk on the outer margins of 
the palms, or on the knuckles.''^ Their hands, however, are 
admirably adapted for climbing trees. Monkeys seize thin 
branches or ropes, with the thumb on one side and the fingers 
and palm on the other, in the same manner as we do. They 

*8 Quot*d by Mr. Lawson Tail in his 1869. Dr. Keller is likewise quoted to th« 
"Law of Natural Selection," "Dublin sani- eiTect. 
Quarterly Journal of Medical Science," Feb. 6-» (J-ven," Anat. of Vertebrates," iiL p> 9% 

€6 THE DESCENT OF MAN", [part i. 

can thus also lift rather large objects, such as the neck of a bot- 
tle, to their mouths. J)al)oons 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 doul)t they thus extract eggs and the young from the nests 
of birds. American monkeys beat the wild oranges on the 
branches until the rind is cracked, and then tear it off with the 
iingers of the two hands. In a wild state they break open hard 
fruits with stones. Other monkeys o[jen 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 iu 
these various actions, and, as I have myself seen, are quite un- 
able to throw a stone with precision. 

It seems to me far from true that because *' objects are 
grasped clumsily " by monkeys, '' a much less specialized or- 
gan 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 disad- 
vantageous for climbing, for the most arboreal monkeys in 
the world, namely, Ateles hi America, Colobus in Africa, 
and Hylobates in Asia, are either thumbless, or their toes pai- 
tially cohere, so that their limbs are converted into mere grasp- 
ing hooks. ^^ 

As soon as some ancient member in the great series of the 
Primates came to be less arboreal, owing to a change in its 
manner of procuring subsistence, or to some change in the sur- 
rounding 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 

'0 "Quarterly Review," April, 1869, p. (Brehm, "Thierleben," B. i. s. 50), but 

392. whether a better cHmber than the species of 

"^ In Hylobates syndactylus, as the the allied genera, I do not know. It de- 
name expresses, two of the toes regularly serves notice that the feet of the sloths, the 
cohere ; and this, as Mr. Blyth informs me, most arboreal animals in the world, arS 
is occasionally the case with the toes of H, wonderfully hook-like. 
ugilis, lar, and leuciscus. Colobus is ^^ Brehm, -'Thierleben," B. i. s. 8a 
Strictly arboreal and extraordinarily active 


most conspicuous characters. Man could not have attained 
his present dominant position in the world without the use of 
his hands, which are so admirably adapted to act in obedience 
to his will. Sir C. Bell'^ insists that ''the hand supplies all 
instruments, and by its correspondence with the intellect gives 
him universal dominion." But the hands and arms could 
hardly have become perfect enough to have manufactured 
weapons, or to have hurled stones and spears with a true aim, 
as long as they were habitually used for locomotion and for 
supporting the whole weight of the body, or, as before re- 
marked, so long as they wer^ especially fitted for climbing 
trees. Such rough treatment would also have blunted the sense 
of touch, on wnich their delicate use largely depends. From 
these causes alone it would have been an advantage to man to 
become a biped ; but for many actions it is indispensable that 
the arms and whole upper part of the body should be free ; and 
he must for this end stand firmly on his feet. To gain this 
great advantage, the feet have been rendered flat ; and the great 
toe has been peculiarly modified, though this has entailed the 
almost complete loss of its power of prehension. It accords 
with the principle of the division of physiological labor pre- 
vailing throughout the animal kingdom, that as the hands be- 
came perfected for prehension, the feet should have become 
perfected for support and locomotion. With some savages, 
however, the foot has not altogether lost its prehensile power, 
as shown by their manner of 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-emi- 
nent success in the battle of life, there can be no doubt, then 
I can see no reason why it should not have been advan- 
tageous 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 otherwise to obtain food. The best built individuals 
would in the long run have succeeded best, and have survived 
in larger numbers. If the gorilla and a few allied forms had 

_ 7S "The Hand," etc., '* BridgewaterTrea- given good rases of the use of tfie foot as a 

tise," 1833, p. 38. prshensile organ by man ; and has also 

'* Hackelhas an excellent discussion on written on the manner of progression of the 

the steps by which man became a biped; higher apes, to which I allude in the follow 

.» M 

Natiirliche Schopfungsgescliichte," 1868, ins; paragraph ; see also Owen (*' Anatomy 
s. 507. Dr. Kiichner ("Conferences sur la of Vertebrates," vol. iii. p. 71) on this latW 
Xt)i<^ne Darwiwienne, 1869, p. 135) has subject. 

18 THE DESCENT OF MAN, {part x. 

become extinct, it might have been argued, with great force 
and apparent truth, that an animal could not have l)een 
gradually converted from a quadruped into a biped, as all the 
individuals in an intermediate condition would have been mis- 
erably ill-fitted for progression. But we know (and this is well 
worthy of reflection) that the anthropomorphous apes arc nov/ 
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 Hylo- 
bates, 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 quad- 
ruped and a biped; but, as an unprejudiced judge '^^ insists, 
the anthropomorphous 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 carved, and 
the head fixed in an altered position, all which changes have 
been attained by man. Prof. Schaaffhauseii ''^ maintains that 
** the powerful mastoid processes of the human skull are the 
result of his erect position ; ' ' and these processes are ateent 
in the orang, chimpanzee, etc , and are smaller in the gorilla 
than in man. Various other structures, which appear connected 
with man's erect position, might here nave 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 shows that certain actions are habitually per- 

'* Prof. Broca, La Constitution des Ver- translated in " Anthropological Review," 

t&bres caudales : "La Revue d'Anthropo- Oct., 1868, p. 428. Owea ("Anatomy of 

ioeie," 1872, p. 26 (separate copy). Vertebrates," vol. ii., 1666, p. 551) on dl^ 

^» ** On the Primitiva Form of the Skull," mastoid processes in the higher ape». 


formed and must be serviceable. Hence the individuals which 
performed them best would tend to survive in greater numbers. 
The free use of the arms and hands, partly the cause and 
partly the result of man's erect position, appears to have led in 
an indirect manner to other modifications of structure. The 
early male forefathers of were, as previously stated, prob- 
ably furnished with great canine teeth ; but as they gradually 
acquired the habit of using stones, clubs, or other weapons, for 
fighting with their enemies or rivals, they would use their jaws 
and teeth less and less. In this case, the jaws, together with 
the teeth, would become reduced in size, as we may feel almost 
sure from innumerable analogous cases. In a future chapter 
we shall meet with a closely parallel case, in the reduction or 
complete disappearance of the canine teeth in male rumi- 
nants, apparently in relation with the development of their 
horns ; and in horses, in relation to their habit of fighting with 
their incisor teeth and hoofs. 

In the adult male anthropomorphous apes, as Rutimeyer "" 
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 ani- 
mals *' 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 cer- 
tainly affect the teeth of the females through inheritance. 

As the various mental faculties gradually developed them- 
selves the brain would almost certainly become larger. No one, 
I presume, doubts that the large proportion which the size of 
man's brain bears to his body, compared to the same proportion 
in the gorilla or orang, is closely connected with his higher 
mental powers. We meet with closely analogous facts with 
insects, for in ants the cerebral ganglia are of extraordinary 
dimensions, and in all the Hymenoptera these ganglia are many 
times larger than in the less inteUigent 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 

" " Die Grenzen der Thierwelt, eine Be- also Mr. Lowne, " Anatomy and Phys. ot 

trachtung zu Darwin's Lehre," 1868, s. 51. the Muscmfomitoria" 1870, p. 14. My son, 

'* Dujardin, " Annales des Sc. Nat.," 3d Mr. F. Darwin, dissected for me the cerebral 

aeries, Zoolo£., torn, xiv., 1850, p. 203. Sec ganglia of the Formica rufa. 

70 THE DESCENT OF MAN, [part i. 

extraordinary mental activity with an extremely jfmall al)so- 
liite mass of nervous matter: thus the wonderfully diversified 
instincts, mental powers, and affections of ants are notorious, 
yet their cerebral ganglia are not so large as the quarter of a 
small i)in's head. Under this point of view, the brain of an 
ant is one of the most marvellous atoms of matter in the world, 
perhai^s more so than the brain of a man. 

The belief that there exists in man some close relation between 
the size of the brain and the development of the intellectual 
faculties is supported by the comparison of the skulls of savage 
and civilized races, of ancient and modern people, and by the 
analogy of the whole vertebrate series. Dr. J. Barnard Davis 
has proved, "^^ by many careful measurements, that the mean in- 
ternal capacity of the skull in Europeans is 92.3 cubic inches j in 
Americans 87.5 ; in Asiatics 87.1 ; and in Australians only 81.9 
cubic inches. Prof. Broca^ found that the nineteenth cen- 
tury skulls from graves in Paris were larger than those from 
vaults of the twelfth century, in the proportion of 1484 to 1426 ; 
and that the increased size, as ascertained by measurements, was 
exclusively in the frontal part of the skull — the seat of the intel- 
lectual faculties. Pri chard is persuaded that the present inhab- 
itants 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 gen- 
erally larger and the convolutions are more complex in the 
more recent forms. On the other hand, I have shown ^ 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 con- 

'» *' Philosophical Transactions," 1869, p. been promptly eliminated in the savage state, 

513. On the other hand, with savages, the aver- 

^""Les Selections," M. P. Broca, "Re- age includes only the more capable indi- 

vue d' Anthropologic," 1873 ; see also, as viduals, who have been able to survive under 

quoted m C. Vogt's " Lectures on Man," extremely hard conditiuns of life. Jiroca 

Eng. translat. , 1864, pp. 88, 90. Prichard, thus explains the otherwise inexplicable 

*' Phys. Hist, of Mankind," vol. i., 1838, p. fact, that the mean capacity of the skull ot 

305. the ancient Troglodytes of Lozere is greater 

^^ In the interesting article just referred than that of modern Frenchmen, 

to. Prof. Broca has well remarked, that in *' " Comptes-rendus des Sciences," etc., 

civilized nations the average capacity of June i, 1868. 

the skull must be lowered by the preserva- *•' "The Variation of Animal5= and Plantt 

tion of a considerable number of individuals, under Domestication," vol. i. pp. 124-12^ 
weak in mind and Wody, who would have 


fined during many generations, so that they have exerted 
their intellect, instincts, senses, and voluntary movements but 

The gradually increasing weight of the brain and skull in 
man must have influenced the development of the supporting 
spinal column, more especially while he was becoming erect. 
As this change of position was being brought about, the internal 
pressure of the brain will also have influenced the form of the 
skull ; for many facts show how easily the skull is thus affected. 
Ethnologists believe that it is modified by the kind of cradle in 
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 backward, owing to disease, one of the two 
eyes has changed its position, and the shape of the skull has 
been altered apparently by the pressure of the brain in a new 
direction.^ I have shown that with long-eared rabbits even so 
trifling a cause as the lopping forward of one ear drags forward 
almost every bone of the skull on that side ; so that the bones 
on the opposite side no longer strictly correspond. Lastly, if 
any animal were to increase or diminish much in general size, 
without any change in its mental powers, or if the mental 
powers were to be much increased or diminished, without any 
great change in the size of the body, the shape of the skull 
would almost certainly be altered. I infer this from my obser- 
vations on domestic rabbits, some kinds of which have become 
very much larger than the wild animal, while others have 
retained nearly the same size, but in both cases the brain has 
been much reduced relatively to the size of the body. Now I 
was at first much surprised on finding that in all these rabbits 
the skull had become elongated or dolichocephalic ; for instance, 
of two skulls of nearly equal breadth, the one from a wild rab- 
bit and the other from a large domestic kind, the former was 
3.15 and the latter 4.3 inches in length.^ One of the most 
marked distinctions in different races of men is that the skull 
in some is elongated, and in others rounded ; and here the ex- 
planation suggested by the case of the rabbits may hold good ; 

8* Schaaffhausen gives from Blumenbach that in certain trades, such as that of a shi.e • 

and Busch the cases of the spasms and maker, where the head is habitually held 

cicatrix, in " Anthropolog. Review," Oct. forward, the forehead becomes more rounded 

1868. p. 420. Dr. Jarrold ('' Anthropologia," and prominent. 

l8o8, pp. 115, n6) adduces from Camper '^' " Variation of Animals," etc., vol. i. p. 

and from his own observations, cases of the IT7, on the elongation of the skull ; p. il^ 

modification of the skull from the head being on the effect of the lopping of one ear* 
fixed in an unnatural position. He believes 


for Welcker finds that short *'men indinc more to brachy- 
cephaly, and tall men to dolichocephaly ; " *^and tall men may 
be compared with the larger and longer- bodied rabbits, all of 
which have elongated skulls, or are dolichocephalic. 

From these several facts we can understand, to a certain 
extent, the means by which the great size and more or less 
rounded form of the skull have been acquired by man ; and 
these are characters eminently distinctive ol 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 
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 rhinoc- 
eroses 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 ^ 
-han 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, favors 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, gen- 
erally thickest on the upper surface,^ is opposed to the suppo- 

•• Quoted by Schaaffhausen, in "An- monkeys and of other mammals being more 

thropolog. Review," Oct., 1868, p. 419. thickly clothed than the lower surfaces. 

*' Owen, " Anatomy of Vertebrates," vol. This has likewise been observed by varioss 

lii. p. 61^ authors. Prof. P. Gervais ("Hist. Nat. des 

®8 Isidore Geoffroy St.-Hilaire remarks Mammif^res," torn, i., 1854. p. 28), however, 

(" Hist. Nat. Gendrale," torn, ii., 1859, pp. states that in the Gorilla the hair is thinnci 

ai5-2i7) on the bead of man being covered on the back, where it is partly rubbed ofl^ 

with long hair ; also on ^e upper surfaces of than o]i the lower surface. 


sition that man became naked through the action of the sun. 
Mr. Belt believes^ that within the tropics it is an advantage to 
man to be destitute of hair, as he is thus enabled to free himself 
of the multitude of ticks (acari) and other parasites, with which 
he is often infested, and which sometnnes 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 specialized means 
of relief. The view which seems to me the most probable is 
that man, or rather primarily woman, became divested of hair 
for ornamental purposes, as we shall see under Sexual Selection ; 
and, according to this belief, it is not surprising that maa 
should differ so greatly in hairiness from ail other Primates, for 
characters, gained through sexual selection, often differ to an 
extraordinary degree in closely related forms. 

According to a popular impression, the absence of a tail is 
eminently distinctive of man ; but as those apes which come 
nearest to him are destitute of this organ, its disappearance does 
not relate exclusively to man. The tail often differs remark- 
ably 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 vertebrae ; in others it consists of a scarcely visible 
stump, containing only three or four vertebrae. In some kinds 
of baboons there are twenty-five, while 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 toward the end ; and this, I pre- 
sume, results from the atrophy of the terminal muscles, together 
with their arteries and nerves, through disuse, leading to the 
atrophy of the tenninal bones. But no explanation can at 
present be given of the great diversity which often occurs in 
Its length. Here, however, we are more specially concerned 
with the complete external disappearance of the tail. Prof. 
Broca has recently shown ^^ that the tail in all quadrupeds 
consists of two portions, generally separated abruptly from each 
other ; the basal portion consists of vertebrae, more or less per- 

•'The "Naturalist in Nicaragua," 1874, '<> Mr. St. George Mivart, " Proc. Zoolog. 

p. 209. As some confirmation of Mr. Belt's Soc," 1865, pp. 562, 583. Dr. J. E. Gray, 

view, I may quote the following passage "Cat. Brit. Mus. : Skeletons." Owen, 

from Sir W. Uenison {"Varieties of Vice- "Anatomy of Vertebrates," vol. ii. p. 517. Isi- 

Regal Life," vol. i., 1870, p. 440) : " It is dore Geofiroy, " Hist. Nat. Gen.," torn. iL 

said to be a practice with the Australians, p. 244. 

when the vermin get troublesome, to singe *' " Revue d' Anthropologic," 1872: "La 

tiMmselves." Constitution des Vertebres cau dales." 

(D}-VoL % 

74 THE D ESC Em OF MAI\r. |pa»t lb 

fectly channelled and furnislK'd with apoMhyses like ordinary 
vertebiaj ; whereas those of the terminal portion are not chan- 
nelled, are almost smooth, and scarcely resemble true vertebrrc. 
A tail, though not externally visible, is really present in man 
and the anthropomorphous apes, and is constructec on exactly 
the same pattern in both. In the terminal portion the ver- 
tebrre, constituting the os coccyx^ are quite rudimentary, being 
much reduced in size and number. In the basal i)ortion 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 acces- 
sory sacral vertebrae. These are of functional importaiice by 
supporting certain internal parts and in other ways ; and their 
modification is directly connected with the erect or semi -erect 
attitude of man and the anthropomorphous apes. This con- 
clusion is the more trustworthy, as Broco formerly held a dif- 
ferent view, which he has now abandoned. The modification, 
therefore, of the basal caudal vertebrae in man and the higher 
apes may have been effected, directly or indirectly, through 
natural selection. 

But what are we to say about the rudimentary and variable 
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 brunneus is formed of 
eleven vertebrae, including the embedded basal ones. The ex- 
tremity 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 onto itself to the left ; 
and this terminal part, which includes the hook-like portion, 
serves ** to fill up the interspace between the upper divergent 
portion of the callosities; " so that the animal sits on it, and 
thus renders it rough and callous. Dr. Anderson thus sums up 
his observations: ** These facts seem to me to have only one 

•a «'Proc. Zoolog. Soc.," 1872, p. 2Z0» 


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 circum- 
stance 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 be- 
tween the callosities, to escape being pressed between them and 
the ground, and that in time the curvature became permanent, 
fitting in of itself when the organ happens to be sat upon." 
Under these circumstances it is not surprising that the surface 
of the tail should have been roughened and rendered callous ; 
and Dr. Murie,^^ who carefully observed this species in the 
Zoological Gardens, as well as three other closely allied forms 
with slightly longer tails, says that when the animal sits down, 
the tail '* 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 have evidence that mutila- 
tions 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 genera- 
tions have become rudimentary and distorted, from being con- 
tinually rubbed and chafed. We see the projecting part in this 
condition in the Macacus brunneus, and absolutely aborted in 
the M. ecaudatus and in several of the higher apes. Finally, 
then, as far as we can judge, the tail has disappeared in man 
and the anthropomorphous apes, owing to the terminal por- 
tion having been injured by friction during a long lapse of 
':ime ; the basal and embedded portion having been reduced 
and modified, so as to become suitable to the erect or semi -erect 

1 have now endeavored to show that some of the most dis- 
t-ucti ve characters of man have in all probabiHty been acquired, 
either directly, or, more commonly, indirectly, through natural 
selection. We should bear in mind that modifications in struct- 
ure or constitution which do not serve to adapt an organism 
to its habits of life, to the food which it consumes, or passively 

«" " Proc. Zoolog. Soc," 1872, p. 786. fer to Mr. Salvin's intereiting case of the 

•* I allude to Dr. Brown-Seqiiard's ob- apparently inherited effects of mot-mots bit- 

servations on the transmitted effect of an ing off the barbs of their own tail-feathers, 

operation causing epilepsy in guinea-pigs, See also, on the general subject, "Variation 

and likewise more recently on the analogous of Animals and Plants under Domestica* 

effects of cutting the sympntheticnt^rve in the tion," vol. ii. pp. 22-34. 
Kisck. I shall hereafter have occasion to re- 


to the surrounding conditions, cannot have been thus acquired. 
We must not, however, be too confident in deriding what modi- 
fications are of service to each being : we should remember 
how httle we know about the use of many parts, or what 
changes in the blood or tissues may serve to fit an organism 
for a new climate or new kinds of food. Nor must we forget 
the principle of correlation, by which, as Isidore Geoffroy 
has shown in the case of man, many strange deviations of 
structure are tied together. Independently of correlation, a 
change in one part often leads, through the increased or de- 
creased use of other parts, to other changes of a quite unex- 
pected 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 color 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 specialpurpose, might induce other 
changes. We should especially bear in mind that modifications 
acquired and continually used during past ages for some useful 
purpose would probably become firmly fixed, and might be 
long inherited. 

Thus a large yet undefined extension may safely be given to 
the direct and indirect results of natural selection ; but I now 
admit, after reading the essay of Nageli on plants, and the 
remarks by various authors with respect to animals, more 
especially those recently made by Prof. Broca, that in the ear- 
lier 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 natural selection. Nevertheless, I did not 
formerly consider sufficiently the existence of structures which, 
as far as we can at present judge, are neither beneficial nor 
injurious ; and this I believe to be one of the greatest oversights 
as yet detected in my work. I may be permitted to say, as 
some excuse, that I had two distinct objects in view : firstly, 
to show that species had not been separately created, and, 
secondly, that natural selection had been the chief agent of 

M *'Tbe Variation of Animals and Plants under Domestication,'* vol. ii. pp. 280^ sSs* 


change, though lurgely aided by the inherited effects of habit, 
and slightly by the direct action of the surrounding conditions. 
I was not, however, able to annul the influence of my former 
belief, then almost universal, that each species had been pur- 
posely created ; and this led to my tacit assumption that every 
detail of structure, excepting rudiments, was of some special, 
though unrecognized, service. Anyone with this assumption 
in his mind would naturally extend too far the action of natural 
selection, either during past or present times. Some of those 
who admit the principle of evolution, but reject natural selec- 
tion, seem to forget, when criticising my book, that I had 
the above two objects in view ; hence if I have erred in 
giving to natural selection great power, which I am very 
far from admitting, or in having exaggerated its power, 
which is in itself probable, I have at least, as I hope, done 
good service in aiding to overthrow the dogma of separate 

It is, as I can now see, probable that all organic beings, 
Including man, possess peculiarities of structure which neither 
are now nor were formerly of any service to them, and which, 
therefore, are of no physiological importance. We know not 
what produces the numberless slight differences between the 
individuals of each species, for reversion only carries the 
problem a few steps backward ; but each peculiarity must 
have had its efficient cause. If these causes, whatever they 
may be, were to act more uniformly and energetically during a 
lengthened period (and against this no reason can be assigned), 
the result would probably be not a mere sHght individual dif- 
ference, but a well-marked and constant modification, though 
one of no physiological importance. Changed structures, which 
are in no way beneficial, cannot be kept uniform through natural 
selection, though the injurious will be thus eliminated. Uni- 
formity of character would, however, naturally follow from the 
•assumed uniformity of the exciting causes, and likewise from 
the free intercrossing of many individuals. During successive 
periods the same organism m.-'ght, in this manner, acquire 
successive modifications, vv^hich would be transmitted in a nearly 
uniform state as long as the exciting causes remained the same 
and there was free intercrossing. With respect to the exciting 
causes we can only say, as when sj^eaking of so-called spon- 
taneous variations, that they relate much more closely to ihs 
constitution of the varying organism than to the nature of tho 
conditions to v/hich it has been subjected. 

jr5 THE DESCENT OF ATAX :.'\ftTfc 

Conclusion. — In this chapter we /la' e seen that as man at the 
piesent ilay is liable, like every other, 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-like 
progenitors, probably lived in society. With strictly social 
animals, natural selection sometimes acts on the individual, 
through the preservation of variations which are beneficial to 
the community. A community which includes a large number 
of well-endowed individuals increases in number, and is victo- 
rious over other less favored ones, even although each separate 
member gains no advantage over the others of the same com- 
munity. Associated insects have thus acquired m.any remark- 
able structures, which are of little or no service to the individual, 
such as the pollen-collecting apparatus, or the sting of the 
worker-bee, or the great jaws of soldier-ants. With the highei 
social animals I am not aware that any structure has been modi- 
fied solely for the good of the commu' :y, th -igh som.e are of 
secondary service to it. For instance, the horns oi' ruminants and 
the great canine teeth of baboons appear to have been acquired 
by the males as weapons for sexual strife, but they are used in de- 
fence of the herd or troop. In regard to certain niental powers 
the case, as we shall see in the fifth chapter, is wholly different ; 
for these faculties have been chiefly, or even exclusively, gained 
for the benefit of the community, and the individuals thereof 
have at the same time gained an advantage indirectly. 

It has often been objected to such views as the foregoing th?a 
man is one of the most helpless and defenceless creatures in tha 


world ; and that during his early and less well-developed 
condition he would have been still more helpless. The Duke 
of Argyll, for instance, insists'-*^ that ''the human frame has 
diverged from the structure of brutes, in the 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 \ijd 
slight power of discovering food or of avoiding danger by smell. 
To these deficiencies there might be added one still more 
serious, namely, that he cannot climb quickly, and so escape 
from enemies. The loss of hair would not have been a great 
injury to the inhabitants of a warm country, for we know that 
the unclothed Fuegians can exist under a wretched climate. 
When we compare the defenceless state of man with that ol 
apes, we must remember that the great canine teeth with which 
the latter are provided are possessed in their full development 
by the males alone, and are chiefly used by them for fighting 
with their rivals ; yet the females, which are not thus provided, 
manage to survive. 

In regard to bodily size or strength, we do not know whether 
man is descended from some small species, like the chimpanzee, 
or from one as powerful as the gorilla ; and, therefore, we cannot 
Bay whether man has become larger and stronger, or smaller 
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 perhaps 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 
sprung from some comparatively weak creature. 

The small strength and speed of man, his want of natural 
weapons, etc., are more than counterbalanced, firstly, by his 
intellectual powers, through which he has formed for him.self 
weapons, tools, etc., though still remaining in a barbarous 
state, and, secondly, by his social qualities, which lead him to 
give and receive aid from his fellow-men. No country in the 
world abounds in a greater degree with dangerous beasts than 
Southern Africa ; no country presents more fearful physical 
hardships than the Arctic regions ; yet one of the puniest ot 

Jio "Primeval Maji," i866b ^ 6^ . 


races, that of the Bushmen, maintains itself in Suutliern Africa, 
as do the dwarfed l'ls(|uimaux in the Arctic rcgioris. The an- 
cestors 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, while 
gradually losing their brute-like powers, such as that of climb- 
ing trees, etc. But these ancestors would net 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 Austral*.!, 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 inher- 
ited effects of habit, would, under favoral)le conditions, have 
sufficed to raise man to his present high position in the organic 



The difference in mental power between the highest ape and the lowest 
>«a.vage, immense — Certain instincts in common — The emotions — 
( uriosity — Imitation — Attention — Memory — Imagination — Reason— 
I'^ogressive 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 lov/est 
savages, who has no words to express any number higher than 
four, and who uses hardly any abstract terms for common objects 
or for the affections,^ with that of the most highly organized 
ape. The difference would, no doubt, still remain immense, 
even if one of the higher apes had been improved cr civilized 

1 See the eviclencf on those points, as given by Lubbock, " FrcUstoric i'imes,'* }ft 


as much as a dog has been in comparison wUh its parent-form, 
the wolf or jackal. The Fuegians rank among the lowest bar- 
barians ; 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 thas& 
<of the lower animals, then we should never have been able to 
convince ourselves that our high faculties had been gradually 
developed. But it can be shown that there is no fundamental 
difference of this kind. We must also admit that there is a 
much wider interval in mental power between one of the lowest 
fishes, as a lamprey or lancelet, and one of the higher apes, than 
between an ape and man \ yet this interval is filled up by num- 
berless gradations. 

Nor is the difference slight in moral disposition between a 
barbarian, such as the man described by the old navigator 
Byron, who dashed his child on the rocks for dropping a basket 
of sea-urchins, and a Howard or Clarkson ; and in intellect, be- 
tween a savage who uses hardly any abstract terms and a New- 
ton 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 show that there is no funda- 
mental difference between man and the higher mammals in their 
mental faculties. Each division of the subject might have been 
extended into a separate essay, but must here be treated briefly. 
As no classification of the mental powers has been universally 
accepted, I shall arrange my remarks in the order most con- 
venient for my purpose ; and will select those facts which have 
struck me most, with the hope that they may produce some 
effect on the reader. 

With respect to animals very low in the scale, I shall give 
some additional facts under Sexual Selection, showing that theit 
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 inquiry, 
that it is the unanimous opinion of all those who have long at- 
t^4^d to animals of many kinds, including birds, that the io- 

82 THE DESCENT OF MAN, [vkvci / 

dividuals difTer greatly in every mental characteristic. In what 
manner the mental powers were first develoi)ed in the lowest 
organisms is as hojieless an inciuiry as how life itself firsf 
originated. These are problems for the distant future, if tliey 
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, per- 
haps, 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 ihat this was due to instinct, but 
we cannot feel sure that it is not the result of both animals hav- 
ing similar wants, and possessing similar powers of reasoning. 
These apes, as we may assume, avoid the many poisonous fruits 
of the tropics, and man has no such knowledge ; but as our 
domestic animals, when taken to foreign lands, and when first 
turned out in the spring, often eat poisonous herbs, which they 
afterward avoid, we cannot feel sure that the apes do not learn 
from their own experience or from that of their parents what 
fruits to select. It is, however, 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. Cuvier maintained that instinct and intelli- 
gence stand in an inverse ratio to each other ; and some have 
thought that the intellectual faculties of the higher animals have 
been gradually developed from their instincts. But Pouchet, 
in an interesting essay,'' has shown that no such inverse ratio 
really exists. Those insects which possess the most wonderful 
instincts are certainly the most i/iteliigent. In the vertebrate 
series, the least intelligent members, namely fishes and amphi- 
bians, do not possess complex instincts ; and among mammals 
the animal most remarkable for its instincts, namely, the beaver, 
is highly intelligent, as will be admitted by everyone who has 
read Mr. Morgan's excellent work.^ 

Although the first dawnings of intelligence, according to Mr. 

2 " L'Instinct chez les Insectes." '■ Revue ^ " ']['he American Reaver and his Works,* 
4es De»x Mondes," Feb., sSjOj p. 690, ib68. 


rlerbert Spencer,^ have l)een developed through the multiphca- 
«:ion and co-ordination of reflex actions, and although many of 
die simpler instincts graduate into reflex actions, and can hardly 
oe distinguished from them, as in the case 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 
antaught character, and be replaced by others performed by the 
aid of the free will. On the other hand, some intelligent actions, 
after being performed during several generations, become con- 
verted into instincts and are inherited, as when birds on oceanic 
islands learn to avoid man. These actions may then be said 
to be degraded in character, for they are no longer performed 
through reason or from experience. But the greater number of 
the more complex instincts appear to have been gained in a 
wholly different manner, through the natural selection of varia- 
tions of simpler instinctive actions. Such variations appear to 
arise from the same unknown causes acting on the cerebral or- 
ganization which induce slight variations or individual differ- 
ences in other parts of the body ; and these variations, owing 
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 learned 
voluntarily, can soon through habit be performed with the 
quickness and certainty of a reflex action, yet it is not improb- 
able that there is a certain amount of interference betv%-cen the 
development of free intelligence and of instinct — which latter 
im7)lies 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 defi- 
nite and inherited — that is instinctive — manner. There seems 
even to exist some relation between a low degree of intelligence 
aiid a strong tendency to the formation of fixed, though not ic- 

* **The Principles of Psychology," zd edit. 1870, pp. 41&-44* 


herited, habits; for, as a sagacious physician remarked to me, 
persons whu are siighcly imbecile tend to act in everything by 
routine or habit, and they are rendered much hapi)ier if this is 

I have thought this digression worth giving, because we may 
easily underrate the mental powers of the higher anmials, and 
especially of man, when we compare their actions founded on 
the memory of past events, on foresight, reason, and imagina- 
tion, 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 varia- 
bility of the mental organs and natural selection, without any 
conscious intelligence on the part of the animal during each 
successive generation. No doubt, as Mr. Wallace has argued,' 
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 
OS well, and a spider its wonderful web quite as well,^ the first 
time it tries, as when old and experienced. 

To return to our immediate subject : the lower animals, like 
man, manifestly feel pleasure and pain, happiness and misery. 
Happiness is never better exhibited than by young animals, 
such as puppies, kittens, lambs, etc., when playing together, 
like our own children. Even insects play together, as has 
been described by that excellent observer, P. Huber,^ who saw 
ants chasing and pretending to bite each other, like so many 

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 
behavior of the female elephants, used as decoys, without ad- 

• "Contributions to the Theory of Nat- work, "Harvesting Ants and Trap-doof 
oral Selection," 1870, p. 212. Spiders," 1873, pp. 126, 128. 

• For the evidence on this head, see Mr. '' " Recherches sur les Mceuts des Fou^ 
Ji Traiieme Moggridge's most interesting mis;" 1810, p« 173. 


mitting 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-tem- 
pered, and easily turn sulky ; others are good-tempered ; and 
these qualities are certainly inherited. Everyone 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 Rengger, 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 v/as himself an eye-witness : At the Cape 
of Good Hope an officer had often plagued a certain baboon, 
and the animal, seeing him approaching one Sunday for parade, 
poured water into a hole and hastily made some thick mud, 
which he skilfully dashed over the officer as he passed by, to 
the amusement of many bystanders. For long afterward the 
baboon rejoiced and triumphed whenever he saw his victim. 

The love of a dog for his master is notorious ; as an old 
writer quaintly says,^ *' A dog is the only thing on this earth 
'hat luvs you more than he luvs himself." 

In the agony of death a dog has been known to caress his 
master, and everyone has heard of the dog suffering under vivi- 
section, who licked the hand of the operator ; this man, unless 
the operation was fully justified by an increase of our knowl- 
edge, or unless he had a heart of stone, must have felt remorse 
to the last hour of his life. 

As Whev/elP^ 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 maternal affection exhibited in the most trifling details; 
thus Rengger observed an American monkey (a Cebus) care- 
fully 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 cer- 

® All the following statements, given on the * Quoted by Dr. Lauder Lindsay, in hi* 

authority of these two naturalists, are taken "Physiology of Mind in the Lower Ani* 

from Rengger*s "Naturgesch. der Sauge- mals ;"" Journal of Mental Science," Apri^ 

thiere von Paraguay," 1830, s. 41-57, and 1871, p. 38. 

from Brebm's " Thierleben," B. i. s. 10-87 "» " Bridgewater Treatise," p. 263. 

•?*0 THE DE^CiljNT of man. IPART t 

tain kinds kept under confinement by Brchm 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 off- 
spring, at which Brehm was surprised, as his monkeys always 
divided everything quite fairly with their own young ones. 
An adopted kitten scratched this affectionate baboon, who cer- 
tainly had a fine intellect, for she was much astonished at be- 
ing scratched, and immediately examined the kitten's feet, and 
without more ado bit off the claws. ^^ In the Zoological Gar- 
dens, I heard from the keeper that an old baboon (C chacma) 
had adopted a Rhesus monkey; but when a young drill and 
mandrill were placed in the cage, she seemed to perceive that 
these monkeys, though distinct species, were her nearer rela- 
tives, for she at once rejected the Rhesus and adopted both of 
them. The young Rhesus, as I saw, was greatly discontented 
at being thus rejected, and it would, hke a naughty child, an- 
noy and attack the young drill and mandrill whenever it could 
do so with safety ; this '^ondiict exciting great indignation in 
the old baboon. Monkeys will also, according to Brehm, de- 
fend 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 
v/hich I shall recur. Some of Brehm's monkeys took much 
delight in teasing a certain old dog whom they disliked, as well 
as other animals, in various ingenious ways. 

Most of the more complex emotions are common to the 
higher animals and ourselves. Everyone has seen how jealous 
a dog is of his master's affection, if lavished on any other creat- 
ure ; and I have observed the same fact with monkeys. This 
3hows that animals not only love, but have desire to be loved. 
Animals manifestly feel emulation. They love approbation or 
praise 3 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 tiiat a dog feels shame, as distinct from fear, and 
something very like modesty when begging too often for food. A 
great dog scorns the snarling of a little dog, and this may be 

*' A critic, without any grounds ("Quar- Therefore I tried, and found that I could 

terly Review," July, 1871, p. 72), disputes readily seize -.vth my own teeth the sharp 

the possibility of this act as described by little cla.vs ot a kitten nearly five weeks old* 
Prebm, for the sake of discrediting my work 


called magnanimity. Several observers have stated that mon- 
keys certainly dislike being laughed at ; and they sometimes 
invent imaginary offences. In the Zoological Gardens I saw 
a baboon who always got into a furious rage when his keeper 
took out a letter or book and read it aloud to him ; and his 
rage was so violent that, as I witnessed on one occasion, he bit 
his own leg till the blood flowed. Dogs show what may be 
fairly called a sense of humor, as distinct from mere play ; if 
a bit of stick or other such object be thrown to one, he will 
often carry it away for a short distance ; and then, squatting 
down with it on the ground close before him, will wait until 
his master comes quite close to take it away. The dog will 
then seize it and rush away in triumph, repeating the same 
manoeuvre, and evidently enjoying the practical joke. 

We will now turn to the more intellectual emotions and facul- 
ties, which are very important, as forming the basis for the de- 
velopment of the higher mental powers. Animals manifestly 
enjoy excitement, and suffer from ennui, as may be seen with 
dogs, and, according to Rengger, with monkeys. All animals 
feel Wonder, and many exhibit Curiosity. They sometimes 
suffer from this latter quality, as when the hunter plays antics 
and thus attracts them ; I have witnessed this with deer, and 
so it is with the wary chamois, and with some kinds of wild- 
ducks. Brehm gives a. curious account of the instinctive 
dread which his monkeys exhibited for snakes; but their- 
curiosity was so great that they could not desist from occasion- 
ally satiating their horror in a most human fashion, by lifting 
tip 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 n:ionkey-house at the Zoological Gardens, and 
the excitement thus caused was one of the most curious specta- 
cles 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 compart- 
ments. After a time all the monkeys collected round it in a large 
circle, and, staring intently, presented a most ludicrous appear- 
ance. They became extremely nervous ; so that when a wooden 
ball, with which they were familiar as a plaything, was acci- 
dentally moved in the straw, under which it was partly hidden, 
^hey all iastantly started away. I'hese monkeys behaved ver| 

88 THE DESCENT OF MAM. [part t 

differently when a dead fish, a mouse, ^'^ a living turtle, and 
other new objects were placed in their cages ; for, though at 
first fi-ightened, 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 ]3rehm exhibited a strange, though mistaken, instinc- 
tive dread of innocent lizards and frogs. An orang, also, ha^ 
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 extraor- 
dinary degree; some hemiplegic patients and others, at the 
commencement of inflammatory softening of the bra'ii, un- 
consciously imitate every word which is uttered, whether in 
their own or in a foreign language, and every gesture or action 
which is performed near them.^^ Desor^^ has remarked that 
no animal voluntarily imitates an action performect by man, 
until in the ascending scale we come to monkeys , which are 
well known to be ridiculous mockers. Animals, hov/ever, some- 
times imitate each other's actions ; thus two species of wolves, 
which had been reared by dogs, learned to bark, as does some- 
times the jackal,^^ but whether this can be called voluntary 
imitation is another question. Birds imitate the songs of their 
parents, and sometimes of other birds ; and parrots are notori- 
ous imitators of any sound which they often hear. Bureau de 
ia Malle gives an account ^" of a dog reared by a cat, who 
learned to imitate the well-known action of a cat licking her 
paws, and thus washing her ears and face ; this was also wit- 
nessed by the celebrated naturalist, Audouin. I have received 
several confirmatory accounts ; in one of these, a dog had not 
been suckled by a cat, but had been brought up with one, to- 

J' I have given a short account of their |* Quoted by Vogt, " Mdmoire sur las 

behavior on this occasion in my " Expres- Microc^phales," 1867, p. 168. 

eion of the Emotions," p. 43 ^^ " The Variation of Animals and Plants 

'3 W. C. L. Martin, "Nat. Hist, of Mam- under Domesr-': ition," vol. i. p. 27. 

malia," 1841, p. 405. *^ " AnnaW '. des Sc. Nat." (istSeri«s}« 

»* Dr. Bateman "On Aphasia," 1870, p. torn. xxii. p. • *• 


gather with kittens, and had thus acquired the above habit, 
which he ever afterward practised during his hfe of thirteen 
years. Bureau de la Malle's dog Hkewise learned from the 
kittens to play with a ball by rolling it about with his fore- 
paws, and springing on it. A correspondent assures me that 
a cat in his house used to put her paws into jugs of milk hav- 
ing too narrow a mouth for her head. A kitten of this cat 
soon learned the same trick, and practised it ever afterward, 
whenever there was an opportunity. 

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

Hardly any faculty is more important for the intellectual 
progress of man than Attention. Animals clearly manifest this 
power, as when a cat watches by a hole and prepares to spring 
on its prey. Wild animals sometimes become so absorbed when 
thus engaged, that they may be easily approached. Mr. Bartlett 
has given me a curious proof how variable this faculty is in 
monkeys. A man who trains monkeys to act in plays us^d to 
purchase common kinds from the Zoological Society at the price 
of five pounds for each ; but he offered to give double the price, 
if he might keep three or four of them for a few days, in order 
to select one. When asked how he could possibly learn so ?oon 
whether a particular monkey would turn out a good actor, he 
answered that it all depended on their power of attention. If, 
when he was talking and explaining anything to a monkey, its 
attention was easily distracted, as by a fly on the wall or other 
trifling object, the case was hopeless. If he tried by punishment 
to make an inattentive monkey act, it turned sulky. On the 
other hand, a monkey which carefully attended to him could 
always be trained. 

It is almost superfluous to state that animals have excellent 
Memories for persons and places. A baboon at the Cape of Good 
Hope, as I have been informed by Sir Andrew Smith, recognized 
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 al)scnrc of five years and two days. I went 
near the stable where he hved, and shouted to him in my old 
manner ; he showed 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 shown, recognized 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 Richter remarks, ^^ '' who must reflect whether he 
shall make a character say yes or no — to the devil with him ; 
he is only a stupid corpse." Dreaming gives us the best notion 
of this power; as Jean Paul again says, *' The dream is an 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 pow^erof voluntarily combining them. As 
dogs, cats, horses, and probably all the higher animals, even 
birds,^ have vivid dreams, and this is shown by their. movements 
and the sounds uttered, we must admit that they possess some 
power of imagination. There must be something special which 
causes dogs to howl in the night, and especially during moon- 
light, in that remarkable and melancholy manner called baying. 
All dogs do not do so ; and, according to Houzeau,^^ they do 
not then look at the moon, but at some fixed point near the 
horizon. Houzeau thinks that their imaginations are disturbed 
by the vague outlines of the surrounding objects, and conjure 
up before them fantastic images : if this be so, their feelings 
may almost be called superstitious. 

Of all the faculties of the human mind, it will, I presume, be 
admitted that Reason stands at the summit. Only a few per- 
sons now dispute that animals possess some power of reasoning. 
Animals may constantly be seen to pause, deliberate, and re- 
solve. It is a significant fact, that the more the habits of any 

18 " Les McEurs des Fourmis," 1810, p. 1862, p. xxi. Houzeau says that his paro- 

150. kr'ets and canary-birds dreamt : *' Facult^s 

'9 Quoted in Dr. Maudsley's "Physiology Mentfilps." torn. ii. p. i;:;6. 
and Pathology of Mind," 1868, pp. 19, 230 '^ *■ l''^niiic-s M.-ntals? dfet fVuimcU*," 

^^ Dr. Jerdon, " Birds of India," vol. i,, 1872, torn. li. p. ia$. 

CHAP, iii.j utent'al powers, ^i 

particular animal are studied by a naturalist, the more he at- 
tributes to reason and the less to unlearnt instincts. ^'^ In future 
chapters we shall see that some anniials extremely low in the 
scale apparently 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, in- 
stead of continuing to draw the sledges in a compact body, 
diverged and separated when they came to thin ice, so that 
their weight might be more evenly distributed. This was 
often the first warning which the travellers received that the ice 
was becoming thin and dangerous. Now, did the dogs act thus 
from the 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 Esquimau dog, may have acquired an instinct impell- 
ing them not to attack their prey in a close pack, when on thin 

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, how- 
ever, is intimately connected with reason. A curious case has 
been given by Prof. Mobius,^ of a pike, separated by a plate 
of glass from an adjoining aquarium stocked with fish, and 
who often dashed himself with such violence against the glass 
in trying to catch the other fishes, that he was sometimes com- 
pletely stunned. The pike went on thus for three months, but 
at last learned caution, and ceased to do so. The plate of glas? 
was then removed, but the pike would not attack these particu- 
lar fishes, though he would devour others which were afterward 
introduced ; so strongly was the idea of a violent shock associ- 
ated in his feeble mind with the attempt on his former neighbors. 
If a savage, who had never seen a large plate-glass window, 
were to dash himself even once against it, he would for a long 
time afterward associate a shock with a window-frame ; but, 
very differently from the pike, he would probably reflect on the 
nature of the impediment, and be cautious under analogous 
circumstances. Ncvv with monkeys, as we shall presently see, 

*' Mr. L, H. Morgan's excellent work he goes too far in underrating the power o| 

on " The American Heaver," published in Instinct. 

1868. offers a good illustration of this re- ^^ " Die Bewegungen 'Icr ihiere," etC« 

I&ark I cannot help thinking, however, that 1873, P* *^ 

p7 THE DESCENT OV Mj4M Ipart \ 

a painful or merely a clisagrccal)lc imj^ression, from an action 
once performed, is sometimes sufficient to prevent tlie 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 
m [id? 

Houzeau relates^ that, while crossing a wide a«d arid plain 
in Texas, his two dogs suffered greatly from thirst, and that 
between thirty and forty times they rushed down the hollows 
to search for water. These hollows were not valleys, and there 
were no trees in them, or any other difference in the vegetation, 
and as they were absolutely dry there could have been no 
smell of damp earth. The dogs behaved as if they knew that 
a dip in the ground ofjered them the best chance of finding 
water, and Houzeau has often witnessed the same behavior 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 
we'il-known ethnologist, Mr. Westropp, informs me that he ob- 
served 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 in- 
stinct or inherited habit, as they would be of little use to an 
animal in a state of nature. Now, what is the difference be- 
tween such actions, when performed by an uncultivated man, 
and by one of the higher animals ? 

Tne 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 we 
know of savages it is extremely doubtful whether they would do 
so, and a dog certainly would not. But a savage, as well as a 
dog, would search in the same way, though frequently dis- 
appointed ; and in both it seems to be equally an act of rea- 
son, whether or not any general proposition on the subject is 

S4 " Facult^s Men/tales des Animaux," 1872, torn. iL p. 26s« 


consciously placed before the mind.^ The same would apply to 
the elephant and the bear making currents in the air or water. 
The savage would 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 wel/ 
shown by the following actions of American monkeys, whiclv 
stand low in their order. Rengger, a most careful observer, 
states that when he first gave eggs to his monkeys in Paraguay, 
they smashed them, and thus lost much of their contents ; after- 
ward they gently hit one end against some hard body, and 
picked off the bits of shell with their fingers. After cutting 
themselves only once with any sharp tool they would not touch 
it again, or would handle it with the greatest caution. Lumps 
of sugar were often given them wrapped up in paper ; and 
Rengger sometimes put a live wasp in the paper, so that in 
hastily unfolding it they got stung ; after this had once happened, 
they always first held the packet to their ears to detect any 
movement within.^ 

The following cases relate to dogs. Mr. Colquhoun^ winged 
two wild-ducks, which fell on the further side of a stream ; his 
retriever tried to bring over both at once, but could not suc- 
ceed ; she then, though never before known to ruffle a feather, 

'* Prof. Huxley has analyzed with admi- "The Naturalist in Nicaragua," 1874 (p. 

rable clearness the mental steps by which a 119), likewise describes various actions of a 

man, as well as a dog, arrives at a conclu- tamed Cebus, which, I think, clearly show 

sion in a case analogous to that given in my that this animal possessed some reasoning 

text. See his article, " Mr. Darwin's power. 

Critics," in the "Contemporary Review," '■'^ "The Moor and the Loch," p. 45. CoL 

Nov., 1871, p. 462, and in his " Critiques Hutchinson on " Dog Breaking," 1850, (». 

and Essays," 1873, p. 279. 46. 

•• Mr. Belt, in nis most interesting worI% 

94 THE DESCENT OE MAN. (pait i 

deliberately killed one, brought over the other, and returned 
for the dead bird. Col. Hutchinson relates that two partridges 
were shot at once, one being killed, the other wounded ; ths 
latter ran away, and was caught by the retriever, who on her 
return came across the dead bird; **she stopped, evidently 
greatly puzzled, and after one or two trials, finding she could 
not take it up without permitting the escajje of the winged 
bird, she considered a moment, then deliberately murdered it 
by giving it a severe crunch, and afterward brought away both 
together. This was the only known instance of her ever hav • 
ing wilfully injured any game." Here we have reason, though 
not quite perfect, for the retriever might have brought the 
wounded bird first and then returned for the dead one, as in the 
case of the two wild-ducks. I give the above cases, as resting 
on the evidence of two independent witnesses, and because in 
both instances the retrievers, after deliberation, broke through 
a habit which is inherited by them (that of not killing the 
game retrieved), and because they show how strong their 
reasoning faculty must have been to overcome a fixed habit. 

I will conclude by quoting a remark by the illustrious Hum- 
boldt.^ ** The muleteers in South 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 ex- 
pression, dictated by long experience, combats the system of 
animated machines better perhaps than all the arguments of 
speculative philosophy." Nevertheless some writers even yet 
deny that the higher animals possess a trace of reason ; and 
they endeavor to explain away, by what appears to be mere 
verbiage,^^ all such facts as those above given. 

It has, I think, now been shown that man and the higher 
animals, especially the Primates, have some few instincts in 
common. All have the same senses, intuitions, and sensations 
— similar passions, affections, and emotions, even the more 
complex ones, such as jealousy, suspicion, emulation, gratitude, 
and magnanimity ; they practise deceit and are revengeful ; 
they are sometimes susceptible to ridicule, and even have a 

28 " Personal Narrative," Eng. translat., foundation thrjn a great many other meta- 

vol. ill. p. io6. physical distinctions ; that is, the assump- 

"9 I am glad to find that so acute a tion that because you can give two things 

reasoner as Mr. Leslie Stephen (" Darwin- different names, they must therefore have 

ism and Divinity, Essays on Free-think- different natures. It is difficult to under- 

ing," 1873, p. 80), in speaking of the Kup- stand how anybody who has ever kept a 

posed impassable barrier between the minds dog or seen an elephant can have any 

of man and the lower animals, says, "The doubts as to an animal's power of perform* 

distinctions, indeed, which have been in^i the essential processes of reasoning." 
^rawn, seem to us to rest upon no better 


sense of humor; they feel wonder and curiosity ; they possess 
Ihe same faculties of imitation, att:5ntion, 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 impossibility, of the attempt. 
It has been asserted that man alone is capable of progressive 
improvement ; that he alone makes use of tools or fire, domes- 
ticates 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, etc.; believes in 
God, or is endowed with a conscience. I will hazard a few 
remarks on the more important and interesting of these points. 
Archbishop Sumner formerly maintained ^^ that man alone is 
capable of progressive improvement. That he is capable of 
incomparably greater and more rapid improvement than is any 
other animal, admits of no dispute ; and this is mainly due to 
his power of speaking and handing down his acquired knowledge. 
With animals, looking first to the individual, everyone who 
has had any experience in setting traps knows that young ani- 
mals 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, accord- 
ing to the unanimous testimony of all observers, an almost 
incredible amount of sagacity, caution, and cunning ; but trap- 
ping has been there so long carried on, that inheritance may 

•0 See ** Madness in Animals," by Dr. " Quoted by Sir CLycll, '* Antiquity ol 
W. Lauder Lindsay, in " Journal of Mental Man«" p. 497* 
ScicQce^" |uly, 187JU 

96 THE DESCENT OF MAN", Ipart l 

possibly have come into play. 1 have received several accounts 
that when telegraphs are first set up in any district, many birds 
kill themselves by flying against the wires, but that in the 
course of a very few years they learn to avoid this danger, by 
seeing, as it would appear, their comrades killed.*^ 

If we look to successive generations, or to the race, there is 
no doubt that birds and other animals gradually both 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 disturbed. 

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 quahties, such as in aft'ection, 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 quaHty may probably be 
attributed to the habitual exercise of all its faculties in avoid- 
ing extirpation by man, as well as to nearly all the less cunning 
or weak-minded rats having been continuously destroyed by 
him. It is, however, possible that the success of the common 
rat may be due to its having possessed greater cunning than 
its fellow -species, before it became associated with man. To 
maintain, independently of any direct evidence, that no animal 
during the course of ages has progressed in intellect or other 
mental faculties, is to beg the question of the evolution of 
species. We have seen that, according to Lartet, existing 
mammals belonging to several orders have larger brains than 
their ancient tertiary prototypes. 

I^ has often been said that no animal uses any tool ; but the 

•' For additional evidence, with details, '♦ " Lettres Phil, sur I'intelligcnce dea 

see M. Houzeau, "Les Facult^s Mentales," Animaux," nouvelle fedit., 1802, p. 86. 

torn, ii., 1872. p. 147. ^^ Seethe evidence on this head in chap. 

" See, with respect to birds on oceanic i. vol. i., "On the Variation of Animals and 

Islands, my " Journal of Researches during Plants under Domestication." 

tnc Voyage of the Beagle," 1845, p, 398. '• "Proc. Zoolog. Soc,/* 1864, p. x86. 
*' Origin of Species," 5th edit., p. 260. 

th/tf. iil| mental powfrs, 97 

chimpanzee in a state of nature cracks a native fruit, some- 
what like a walnut, with a stone.^ Rengger ^ easily taught an 
American monkey thus to break open hard palm-nuts ; and 
afterward, of its own accord, it used stones to oj)en other kinds 
of nuts, as well as boxes. It thusJso removed the soft rind of 
fruit that had a disagreeable flavor. Another monkey was 
taught to open the lid of a large box with a stick, and after- 
ward it used the stick as a lever to move heavy bodies ; and I 
have myself seen a young orang put a stick into a crevice, slip 
his hand to the other end, and use it in the proper manner as a 
lever. The 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 elephant in a state of 
nature.® I have seen a young orang, when she thought she 
was going to be whipped, cover and protect herself with a blanket 
or straw. In these several cases stones and sticks were em- 
ployed as implements ; but they are likewise used as weapons. 
Brehm ^ states, on the authority of the well-known traveller, 
Schimper, that in Abyssinia when the baboons belonging to one 
species (jC. geladd) 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. Brehm, when accompanying the Duke of Coburg- 
Gotha, aided in an attack with fire-arms on a troop of baboons, in 
the pass of Mensa in Abyssinia. The baboons in return rolled so 
many stones down the mountain, some as large as a man's head, 
that the attackers had to beat a h.^ty retreat, and the pass was 
actually closed for a time against the caravan. It deserves 
notice that these baboons thus acted in concert. Mr. Wallace" 
on three occasions saw female orangs, 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 oflends 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, 

" Sava-^ and Wyman in " Boston Jour- '» The " Indian Field," March 4, i87X, 
ml of Nat. Hist.," vol. iv., 184^-44, p. 383. <o "Thierleben," B. i. s. 79, 82. 

*" Saage^icre von Paraguay," 1830,3. ♦' "The Malay Archipelago," vol it 

9S-56. 1S69, p. 87. 

98 THE DESCENT OF Jlfj4M (part «. 

used to break open nuts witli a stone , and I was assured by thr 
keepers that after using the stone, he hid it in the straw, and 
vould not let any other monkey touch it. Here, then, we 
Jiave 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"*^ rcmarLs, that the fashioning of an 
implement for a special purpose is absolutely peculiar to man ; 
and he considers that this forms an immeasurable gulf between 
him and the brutes. This is no doubt a very important dis- 
tinction ; but there appears to me much truth in Sir J. Lub- 
bock's suggestion,'*^ that v/hen primeval man first used flint- 
stones for any purpose, he would have accidentally splintered 
them, and would then, have used the sharp fragments. From 
this step it would be a small one to break the flints on purpose, 
and not a very wide step to frshion them rudely. This la'ter 
advance, however, may have taken long ages, if we may judge 
by the immense interval of tmie which elapsed before the men 
of the neoHthic 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 oc- 
casionally flows through forests. The anthroi)oinorphous apes, 
guided probably by instinct, build for themselves temporary 
platforms; but as many instincts are largely controlled by 
reason, the simpler ones, such as this of building a platform, 
might readily pass into a voluntary and conscious act. The 
orang is known to cover itself at night with, the leaves of the 
Pandanus ; and Brehm states that one. of his baboons used to 
protect itself from the heat of the sun by throwing a straw* 
mat over its head. In these several habits we probably see 
the first steps toward some of the simpler arts, such as rude 
irchitecture and dress, as they arose among the early progeni- 
tors of man 

Abstraction^ General Conceptions, Self -consciousness Mental 
Individuality. — It would be very difficult for anyone with even 
much mo'*e knowledge than I possess, to determine how far 
animals exhibit any traces of these high mxcntal powers. This 
difficulty arises from the impossibility of judging what passes 
through the mind of an animal ; and again, the fact that writers 

43 "Primeval Man," 1869, pp. 145, 147, <» V Prehistoric Times," 1865, p. 473, etCi 

CHAP, lu.j MEm'AL powers: 99 

differ to a great extent in the meaning which they attribute to 
the above terms, causes a further difficulty. Lf one may judge 
from various articles which have been published lately, the 
greatest stress seems to be laid on the supposed entire absence 
in animals of the power of abstraction, or of forming general 
concepts. But when a dog sees another dog at a distance, it is 
often clear that he perceives that it is a dog i i the abstract > 
for when he gets nearer his whole manner suddenly changes, 
if the other dog be a friend. A recent writer lemarks, 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 neighbor- 
ing tree for a squirrel. Now do not these actions clearly show 
that she had in her mind a general idea or concept that some 
animal is to be discovered and hunted ? 

It may be freely admitted that no animal is self-conscious, 
if by this term it is implied that he reflects on such points a^ 
whence he comes or whither he v/ill go, or what is life and 
death, and so forth. But how can we feel sure that an old dog 
with an excellent memory and some power of imagination, as 
shown by his dreams, never reflects on his past pleasures or 
pains in the chase? And this would be a form of self-con- 
sciousness. On the 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 ov/n existence. It is generally admitted that the higher 
ariimals possess memory, attention, association, and even some 
imagination and reason. If these powers, which differ much 
in different animals, are capable of improvement, there seems 
no great improbability in more complex faculties, such as the 
higher forms of abstraction, and self-consciousness, etc., having 
been evolved through the development and combination of the 
simpler ones. It has been urged against the views here main- 

••* Mr. Hookham, in a letter to Prof. Max «• " Conferences sur la Thfeorie Damii 
Miiller, m the " Birmingham News," May, nienne," French translat., 1869, p. iji. 


tained, that it is impossible to say at what point in the ascend' 
ing scale animals become capable of abstraction, etc. ; 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 im- 
perceptible 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 for- 
ward 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 impres- 
sions as legacies to other atoms falling into the places they 
have vacated is contradictory of the utterance of conscious- 
ness, and is therefore false; but it is the teaching necessi- 
tated by evolutionism, consequently the hypothesis is a false 

Language. — ^This faculty has justly been considered as one of 
the chief distinctions between man and che lower animals. But 
man, as a highly competent judge, Archbishop Wakely remarks, 
is not the only animal that can make use of language to ex- 
press what is passing in his mind, and can understand, more or 
less, what is so expressed by another."^'' In Paraguay the 
Cebus azarce when excited utters at least six distinct sounds, 
which excite in other monkeys similar emotions.^ The move- 
ments of the features and gestures of monkeys are understood 
by us, and they partly understrmd ours, as Rengger and others 
declare. It is a more remarkable fact that the dog, since being 
domesticated, has learned to bark ^^ in at least four or five dis- 
tinct tones. Although barking is a new art, no doubt the wild 
parent-species of the dog expressed their feelings by cries of 
various kinds. With the domesticated dog we have the bark of 
eagerness, as in the chase \ that of anger, as well as growling ; 
the yelp or howl of despair, as when shut up ; the baying at 
night ; the bark of joy, as when starting on a walk with his 
master ; and the very distinct one of demand or supplication, 
as when wishing for a door or window to be opened. Ac- 
cording to Houzeau, who paid particular attention to the 

<• The Rev. Dr. J. M'Cann, " Anti-Dar- «■ Rengger, ibid , s. 45. 

winism," 1869, p. 13. *8 See my "Variation of Animals and 

*' Quoted in "Anthropological Review," Plants under Domestication," vol. i. p. a|b 
I864, p. 158. 


subject, the domestic fowl utters at least a dozen significant 

The habitual use of articulate language is, however, peculiar 
to man ; but he uses, in common with the lower animals, inar- 
ticulate 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 crier- of 
pain, fear, surprise, anger, together with their appropriate ac- 
tions, 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 articu- 
late sounds, for, as everyone 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 sounds 
and ideas ; and this obviously depends on the high develop- 
ment 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 learned. 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 

6j «* Facultes Mentales des Animaux," the " Good morning " a short sentence, 

torn, ii., 1873, pp. 346-349. which was never once repeated after his 

^* See a discussion on this subject in Mr. father's death. He scolded violently a 

E. B. Tylor's very interesting work, "Re- strange dog which came into the room 

searches into the Early History yf Man- through the open window ; and he scolded 

hind," 1865, chaps, ii. to iv. '' another parrot (saying "Von naughty 

'■- [ have received several detailed ac- polly") which had got out of its cage, and 

jounts to thtp eff:^ct. Admiral Sir J. SuUi- was eating apples on the kitchen table. See 

van, whom [ know to be a careful observer, also, to the .same effect, Mouzeau on parrots, 

assures me that .m African parrot, loiia; kept *' Facultes Mentales,'" torn. ii. p. 300. Dr, 

in his father's house, invaria'.ily cAlled cer- A. Moschkau informs nie that he knew a 

tain p<:r.=5ons of tlie household, as well as vis- stTrling which never made a mistake in say- 

itoi"»;, by their names. Ke said *' Good morn- ing in Oerinan " Good morning; " to persons 

mg " to everyone at and " (jood arriving, and " Ciood-by, old fellow," t* 

night " to each as they left th'i room at night, those departing. 1 could add several otiMC 

and never reversed these salutations. To such cases. 
Sir J. S)ilii\an's fatlier, he used to add to 


young children ; while no child has an instinctive tendency to 
brew, bake, or write. Moreover, no philologist now supi)oses 
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 learned from 
their parents or foster-parents. These sounds, as Daines Bar- 
rington^ has proved, "are no more innate than language 
is in man." The first attempts to sing *'may be compared 
to the imperfect endeavor in a child to babble." The young 
males continue practising, or as the bird-catchers say, *' record- 
ing," for ten or eleven months. Their first essays show 
hardly a rudiment of the future song ; but as they grow older 
we can perceive v/hat they are aiming at ; and at last they 
are said ** to sing their song round." Nesthngs which have 
learned the song of a distinct species, as with the canary- 
birds educated in the Tyrol, teach and transmit their new song 
to their offspring. The slight natural differences of song in the 
same species inhabiting different districts may be appositely 
compared, as Barrington remarks, '' to provincial dialects," 
and the songs of allied though distinct species may be com- 
pared with the languages of distinct races of man. I have 
given the foregoing details to show that an instinctive tendency 
to acquire an art is not peculiar to man. 

With respect to the origin of articulate language, after having 
read on the one side the highly interesting works of Mr. Hens- 
leigh Wedgwood, the Rev. F. Farrar, and Prof. Schleicher,^ 
and the celebrated lectures of Prof. Max Miiller, on the 
other side, I cannot doubt that language owes its origin to 
the imitation and modification of various natural sounds, the 
voices of other animals, and man's own instinctive cries, aided 
by signs and gestures. When we treat of sexual selection we 

^3 See some good remarks on this head Bureau de la Malle, in "Ann. des. Sc. Nat.,** 

by Prof. Whitney, in his " Oriental and Lin- 3d series, Zoolog., torn. x. p. 119. 

guistic Studies," 1873, p. 354. He observes ** "On the Origin of Language," by H, 

that the desire of communication between Wedgwood, 1866. '' Chapters on Lan- 

man is the living force, which, in the devel- guage," by the Rev. F. W. Farrar, 1865. 

opment of language, *' works both con- These works are most interesting. See also 

Eciously and unconsciously ; consciously as " De la Phys. et de Parole," par Albert T^e- 

regards the immediate end to be attained; moine, 1865, p. 190. The work on th)s sub- 

unconsciously as regards the further conse- ject, by the late Prof. Aug. Schleicher, has 

quences of the act." been tran.siated by Dr. Bikkers into Eng- 

** Hon. Daines Barrington, in " Philo- lish. under the title of " Darwinism testea bj 

tQpb. TransactJQQs," 1773, p. 263. See also the Science of Language." 1869. 


shall see that primeval man, or rather some early progenitor of 
man, probably first used his voice in producing true musical 
cadences, that is in singing, as do some of the gibbon-apes at 
the present day ; and we may conclude from a widely spread 
analogy, that this power would have been especially exerted 
during the courtship of the sexes — would have expressed variou? 
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 
^iven rise to words expressive 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- 
€ries of danger to their fellows,'"'^ and since fowls give distinct 
warnings for danger on the ground, or in the sky, from hawks 
(both, as well as a third cry, intelligible to dogs),^^ may not 
5ome 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 progenitor of man must have been more highly developed 
than in any existing ape, before even the most imperfect form 
of speech could have come into use ; but we may confidently 
believe that the continued use and advancement of this power 
would have reacted on the mind itself, by enabling and encourag- 
ing 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 
•ise of figures or algebra. It appears, also, that even an ordi- 
nary train of thought almost requires, or is greatly facilitated by, 

*• Vogt, *' Memoire sur les Microc^- two works so often quoted, by Brehm and 

phalcs," 1867, p. 169. With respect to Rengger. 

ravages, 1 have given some facts in my '" Houzeau gives a very curious account 

"Journal of Researches," etc., 1845, p. of his observations on this subject in hif 

ccy^- "Facultes Mentales des Animaux/' toik 

*' See dear evidence on this head in the il. p. 348. 


Bome form of language, for the dumb, deaf, and !)lind girl, 
Laura Bridgman, was observed to use her fuigers while dream- 
ing.^ Nevertheless, a long succession of vivid and connected 
ideas may pass through the mind without the aid of any (oim 
of language, as we may infer from the movements of dogs dur- 
ing their dreams. We have, also, seen that animals are j,ble to 
reason to a certain extent, manifestly without the aid of lan- 
guage. The intimate connection between the brain, as it is now 
developed in us, and the faculty of speech, is well shown by 
those curious cases of brain disease in which speech is specially 
affected, as when the power to remember substantives is lost* 
while other words can be correctly used, or where substantives! 
of a certain class, or all except the initial letters of substantives 
and proper names, are forgotten.^ There is no more 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 handwriting 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 
endeavored to show that they have this power, at least in a 
Hide and incipient degree. As far as concerns infants of from 
ten to eleven months old, and deaf-mutes, it seems to me in- 
credible that they should be able to connect certain sounds 
with certain general ideas as quickly as they do, unless such 

6' See remarks on this head by Dr. tinctness and variety and complexity of 

Maudsley, "The Physiology and Pathol- cognitions, to the full mastery of conscious- 

ogy of Mind," 2d edit., i868, p. 199. ness ; therefore he would fain make thoueht 

^^ Many curious cases have been record- absolutely impossible without speech, identi- 

ed. See, for instance, Dr. "On fying the faculty with its instrument He 

Aphasia." 1870, pp. 27, 31, 53, 100, etc. mightjust as reasonably assert that the hu- 

Also, ■• Inquiries Concerning the Intellectual man hand cannot act without a tool. With 

Powers," by Dr. Abercrombie, 1838, p. 150. such a doctrine to start from, he cannot stop 

'' " The Variation of Animals and Plants short of Miiller's worst paradoxes, that an 

under Domestication," vol. ii. p. 6. infant (z'« fans, not speaking) is not a hu- 

"2 Lectures on "Mr. Darwin's Philosophy man being, and that deaf-mutes do not be- 

of Language," 1873. , come possessed of reason until they learn to 

^^ The judgment of a distinguished phi- twist their fingers into imitation of spoken 

lologist, such as Prof. Whitney, will have words." Max Miiller gives in italics ('" Lect- 

far more weight on this point than anything ures on Mr. Darwin's Philosophy of Lan* 

that I cap say. He remarks ("Oriental and guasre," 1873, third lectur*?) the following 

Linguistic Studies," 1873, P- 297), in speak- aphorism : "There is no thought without 

ing of Bleek's views : " Because on the words, as little as there are words without 

grand scale language is the necessary aux- thought." What a strange definition must 

lliary of thought, indispensable to the devel- here be given to the wo-.d th-^ughtl 
gpmeQt of the power of thinking, to the dis- 


^rlr»as were already formed in their minds. The same remark 
.:y I'c extended to the more intelligent animals ; as Mr. T.eslie 
Stephen observes/^ '* A dog frames a general concept of cits or 
sheep, and knows the corresponding words as well as a philoso- 
pher. And the capacity to understand is as good a proof of 
vocal intelligence, though in an inferior deg^-ee, as the capacity 
to speak. ' ' 

Why the organs now used for speech ?' lould have bee« 
originally perfected for this purpose, rather ihan any other or- 
gans, it is not difficult to s«e. Ants have copsiderable powers 
of intercommunication by means of their antennae, as shown by 
Huber, who devotes a whole chapter to their language. We 
might have, used our fing4srs 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, while thus employed, would have been a serious 
inconvenience. As all the higher mammals possess vocal or- 
gans, constructed on the same general plan as ours, and used as 
a means of communication, it was obviously probable that these 
same organs would be still further developed if the power of 
communication had to be improved ; and this has been effected 
by the aid of adjoining and well adapted parts, namely, the 
^tongue and lips.^ The fact of the higher apes not using their 
vocal organs for speech, no doubt depends on their intelligence 
not having been sufficiently advanced. The possession by them 
of organs, which with long-continued practice might have been 
used for speech, although not thus used, is 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 ansv/er, and it is unreasonable to expect anything 
more definite, considering our ignorance with respect to the 
successive stages of development through which each creatuie 
has passed. 

•* "Essays on Free-thinking," etc., 1873, learns to pronounce single words, and even 

p. 82. ^ short sentences, more readily than almost 

•^ See some good remarks to this effect any other l?ritish bird ; yet. as he adds, 

by Dr. Maudsley. "The Physiology and after long and closely invcsiigating its habits, 

Pathology of Mind," 1868, p. 199. _ he has never known it. in a state of naturct 

" Macgillivray, " Hist, of British Birds," display any unusual capacity for imitatio*. 

vol. ii., 1839, p. 29. An excellent observer, " Researches in Zoology," 1834, p. 158. 
Mr. Blackwall, remarks tliat the magpie 


The formation of different languages and of distinct species, 
and the proofs that both have been developed through a gradual 
orocess, are curiously parallel. ^^ But we can trace the formation 
of many words further back than that of species,- for we ca*^ 
perceive how they actually arose from the imitation of various 
loundb. We find in distinct languages striking homologies du^ 
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 redupHcation of parts, the effectsx)f long- 
continued use, and so forth. The frequent presence of rudi- 
ments, both in languages and in species, is still more remark- 
able. The letter m in the word am, means /; so that in the 
expression I am, a superfluous and useless rudiment has been re- 
taintrd. In the spelling also of words, letters often remain as the 
rudiments 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 birthplaces. Distinct languages may be crossed or 
blended together.® We see variability in every tongue, and new 
words are continually cropping up ; but as there is a limit to 
the powers of the memory, single words, like whole languages, 
gradually become extinct. As Max Muller ^^ has well remarked : 
** A struggle for life is constantly going on among the words 
and grammatical forms in each language. The better, the 
shorter, the easier forms are constantly gaining the upper hand, 
and they owe their success to their own inherent virtue ' ' To 
these more important causes of the survival of certain words, 
mere novelty and fashion may be added ; for there is in the 
mind of man a strong love for slight changes in all things. 
The survival or preservation of certain favored 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 ad- 
vanced as a proof, either of the divine origin of these languages 

" See the very interesting parallelism be- *• See remarks to this effect by the Rev. 

tween the development of species and Ian- F. W. Farrar, in an interesting article ew 

fuages, given by Sir C Lyell in " The titled " Philology and Darwinism," in " Nat 

Geolog. Evidences oftheAnliquity of Man," ore." March 34, 1870, p. 528. 

«6^ chafk JKui. „ ^ "Nature." Jan. 6. i8?o,p. «» 


or of the high art and former civilization of their founders. 
Thus F. von Schlegel writes : "In those languages which ap- 
pear to be at the lowest grade of intellectual culture, we fre- 
quently observe a very high and elaborate degree of art in their 
grammatical structure. This is especially the case with the 
Basque and the Lapponian, and many of the American lan- 
guages. ' * ^ But it is assuredly an error to speak of any language 
a^ an art, in the sense of its having been elaborately and me- 
thodically formed. Philologists now admit that conjugations, 
declensions, etc., originally existed as distinct words, since 
joined together ; and as such words express the most obvious 
relations between objects and persons, it is not surprising that 
they should have been used by the men of most races dur- 
ing the earliest ages. With respect to perfection, the fol- 
lowing illustration will best show how easily we may err : A 
Crinoid sometimes consists of no less than 150,000 pieces of 
shell, '^ all arranged with perfect symmetry in radiating lines ; 
but a naturalist does not consider an animal of this kind as 
more perfect than a bilateral one with comparatively few parts, 
and with none of these parts alike, excepting on the opposite 
sides of the body. He justly considers the differentiation and 
specialization of organs as the test of perfection. So with lan- 
guages ; the most symmetrical and complex ought not to be 
ranked above irregular, abbreviated, and bastardized languages 
which have borrowed expressive words and useful forms of 
construction from various conquering, conquered, or immi' 
grant races. 

From these few and imperfect remarks I conclude that the 
extremely complex and regular construction of many barbar- 
ous languages is no proof that they owe their origin to a spe- 
cial act of creation. "^^ Nor, as we have seen, does the faculty 
of articulate speech in itself offer any insuperable objection 
to the beUef that man has been developed from some lower 

Sense of Beauty. — ^This sense has been declared to be peculiai 
to man. I refer here only to the pleasure given by certain 
colors, forms, and sounds, and which may fairly be called a 
sense of the beautiful ; with cultivated men such sensations are, 
however, intimately associated with complex ideas and trains of 
thought. When we behold a male bird elaborately displaying 

'0 Quoted by C. S. Wake, ** Chapters on ':» See some good remarks on the simpUfi* 
Man," 1868, p. loi. cation of languages, by Sir J. Lubbod^ 

»* BuckUnO, •* Bridgcwater TVeadse,'' p. ** Origin of Civilization,'*^ 1870, p. 278. 

I08 THE DESCENT OF MANi (part l 

his graceful plumes or si)lendid colors before the female, 
while other birds, not thus decorated, make no such display, 
it is impossible to doubt that she admires the beauty of hei 
male i)artner. As women everywhere deck themselves with 
these plumes, the beauty of such ornaments cannot be disputed. 
As we shall see later, the nests of h nming-birds and the 
playing passages of bower- birds are tastefully ornamented 
with gayly colored objects ; and this shows that they must 
receive some kind of pleasure from the sight of such things. 
With the great 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 m.any 
male birds during the season of love are certainly admired by 
the females, of which fact evidence will hereafter be given. It 
female birds had been incapable of appreciating the beautiful 
colors, the ornaments, and voices of their male partners, all the 
labor and anxiety exhibited by the latter in displaying their 
charnis before the females would have been thrown away ; and 
this it is impossible to admit. Why certain bright colors 
should excite pleasure cannot, I presume, be explained, any 
more than why certain flavors and scents are agreeable ; but 
habit has something to do with the result, for that which is at 
first unpleasant to our senses ultimately becomes pleasant, and 
habits are inherited. With respect to sounds, Helmholtz has 
explained, to a certain extent, on physiological principles, v-'hy 
harmonies and certaii? cadences are agreeable. But besides 
this, sounds frequently recurring at irregular intervals are 
highly disagreeable, as everyone will admit who has listened at 
night to the irregular flapping of a rope on board ship. The 
same principle seems to come into play with vision, as the 
eye prefers symmetry or figures with some regular recurrence. 
Patterns of this kind are employed by even the lowest savages 
as ornaments ; and they have been developed through sexual 
selection for the adornment of some male animals. Whether we 
can or not give any reason for the pleasure thus derived from 
vision and hearing, yet man and many of the lower animals are 
alike pleased by the same colors, graceful shading and forn>s, 
and the same sounds. 

The taste for the beautiful, at least as far ?s female beaaty i*i 
concerned, is not of a special nature in the human mii.d ; tor it 
differs widely in the different races of man, and is not quite tht« 
same even in the different nations of the same race. Judging 
firom the hideous ornaments and the equally hideous music 


admired by most savages, it might be urged that their aesthetic 
faculty was not so highly developed as in certain animals, for 
instance, as in birds. Obviously no animal would be capable of 
admiring such scenes as the heavens at night, a beautiful land- 
scape, or refined music; but such high tastes are acquired 
through culture, and depend on complex associations ; they are 
not enjoyed by barbarians or by uneducated persons. 

Many of the faculties, which have been of inestimable service 
to man for his progressive advancement, such as the powers of 
the imagination, wonder, curiosity, an undefined sense of 
beauty, a tendency to imitation, and the love of excitement or 
novelty, could hardly fail to lead to capricious changes of 
customs and fashions. I have alluded to this point, because a 
recent writer^-^ 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, bs we shall hereafter see, likewise 
capricious in their affections, aversions, and sense of beauty. 
There is also reason to suspect that they love novelty for its 
own sake. 

Belief in God — Religion, — ^There is no evidence that man was 
aboriginally endowed with the ennobling beUef in the existence 
of an Omnipotent God. On the contrary, there is ample evi- 
dence, derived not from hasty travellers, but from men who 
have long resided with savages, that numerous races have 
existed,* and still exist, who have no idea of one or more gods, 
and who have no words in their languages to express such an 
idea.*^^ The question is of course wholly distinct from that 
higher one, whether there exists a Creator and Ruler of the 
uiii verse ; and this has been answered in the affirmative by 
s*3me of the highest intellects that have ever existed. 

If, however, we include under the teriti • • religion ' ' the belief 
in unseen or spiritual agencies, the case is wholly different ; for 
dds belief seems to be universal with the less civilized races. 
"^ox 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 

*' "The Spectator," Dec. 4, 1S69, p. 143a, For further facts see Sir J. Lubbock, " Pre- 

** See an excellent article on this subiect hi5;toric Times," 2d edit. 1869, p. 564 ; and 

6y the Rev. F. W. Farrar, in the "Anthiroj>- especially the chapters on ReiigtOD in Uf 

ts^gknl Htfvitfes^^ Aug., tS.x ^ ccxvii **Onsiuof Civilizatki^" iStpik 

no TME DE<;CE1^T OP MA]^, \PkVt l, 

own existence. As Mr. M'Lennan^ has remarked, '* Some 
explanation of the phenomena of Hfe, 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 ani- 
mals, plants, and things, and in the forces of nature, of such 
spirits prompting to action as men are conscious they them- 
selves possess.** It is also probable, as Mr. Tylor has shown, 
that dreams may have first given rise to the notion of spirits; 
for savages do not readily distinguish between subjective and 
objective impressions. When a savage dreams, the figures which 
appear before him aie 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 the faculties of imagination, curiosity, 
reason, etc., had been fairly well developed in the mind of man, 
his dreams would not have led him to believe in spirits, any 
more than in the case of a dog. 

The tendency in savages to imagine that natural objects and 
agencies are animated by spiritual or living essences, is perhaps 
illustrated by a little fact which I once noticed : my dog, a 
full-grown and very sensible animal, was lying on the lawn 
during a hot and still day; but at a little distance a slight 
breeze occasionally moved an open parasol, which would have 
been wholly disregarded by the dog, had any one stood near it. 
As it was, every time that the parasol slightly moved, the dog 
growled fiercely and barked. He must, I think, have reasoned 
to himself in a rapid and unconscious manner, that movement 
without any apparent cause indicated the presence of some 
strange living agent, and that no stranger had a right to be on 
his territory. 

The belief in spiritual agencies would easily pass into the 
belief in the existence of one or more gods. For savages would 

7a •'•The Worship of Animals and Plants," erful, it is propitiated by various gifts and 

Q the " Fortnightly Review," Oct. i, 1869, ceremonies, and its aid invoked. He then 

p. 422. further shows that names or nicknames 

'• Tylor, ** Early History of Mankind,*' given from some animal or other object to 

1865, p. 6. See ailso the three striking chap- Sie early progenitors or founders of a. tribe, 

ters on tfie Development of Religion, m are supposed after a long interval to repre« 

Lubbock's '' Origin of Civilization," 1870. sent the real progenitor of the tribe ; and 

In a like manner, Mr. Herbert Spencer, in such animal or object is then naturally be* 

his ingenious essay in the " Fortnightly Re- lieved still to exist as a spirit, is held sacred, 

view "(May i, 1870, p. 535) accounts for and worshipped as a god. Nevertheless I 

the earliest forms of religious belief through- cannot but suspect that there is a still earlier 

out the world, by man being led through and ruder stage, when anything which man* 

dreams, shadows, and other causes, to look ifests power or movement is thought to bo 

at himself as a double essence, corporeal endowed with some form of life, and with 

•nd spiritual. As the spiritual bein? is mental faculties analogous to OUT flWOt 
tup{)OMd to udst afJter death and to be pow* 


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 remark- 
able, as with savages the belief in bad spirits is far more common 
than that in good ones. 

The feeling of religious devotion is a highly complex one, 
consisting of love, complete submission to an exalted and 
mysterious superior, a strong sense of dependence,'" fear, 
reverence, gratitude, hope for the future, and perhaps other 
elements. No being could experience so complex an emotion 
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 behavior of a dog when returning 
to his master after an absence, and, as I may add, of a monkey 
to his beloved keeper, is widely different from that toward their 
fellows. In the latter case the transports of joy appear to be 
somewhat less, and the sense of equality is shown in every 
action. Prof. 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 unseen spiritual agencies, then in fetishism, polytheism, and 
ultimately in monotheism, would infalliby 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; thetrialofinnocentpersonsby the ordeal of poison 

" See an able article on the " Physical 'schen Art-Lehre," 1869, s. 53. It is said 
Elements of Religion," by Mr. L. Owen (Dr. W. Lauder Lindsay, " Journal of Men- 
Pike, in ** Antliropolog. Review," April, tal Science," 1871, p. 43) that Bacon lonf 
z870, p. Ixiii. ago, and the poet Burns, held the saaf 

'• " ReligioQ, Moral, ctc.» der Darwin- notioQ. 

112 THE D use EX/ OF MAN. fPAKT I. 

or fire; witchcraft, etc. -yet it is well occasionally to rcncct. on 
these superstitions, for they show us what an infinite debt of 
gratitude we owe to the improvement of our reason, to science, 
and to our 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 imbitters every pleasure." These m'serable and indi- 
rect consequences of our highest faculties may be compared 
with the incidental and occasional mistakes of the instincts of 
the lower animals. 



ANIMALS — continued. 

The moral sense — Fundamental proposition — The qualities of social an- 
imals—Origin of sociability — Struggle l^etween opposed instincts — 
Man a social animal — The mere enduring social instincts conquer 
other less persistent instincts — The social virtues alone regarded by 
savages — The self-regarding virtues acquired at a later stage of de- 
velopment — The importance of the judgment of the members of the 
same community od conduct — Transmission of moral tendencies- 

I FULLY subscribe to the judgment of those writers ^ who main- 
tain that of all the differences between man and the lower an- 
imals, the moral sense or conscience is by far the most impor- 
tant. 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 ought, so full of 
high significance. It is the most noble of all the attributes of 
man, leading him without a moment's hesitation to risk his 
life for that of a fellow-creature ; or after due deliberation, ipi- 
pelled simply by the deep feeling of right or duty, to sacrifice 
it in some great cause. Immanuel Kant exclaims, "Duty! 
Wondrous thought, that worktst neither by fond insinuation, 
flattery, nor by any threat, but merely by holding up thy naked 

'9 " Prehistoric Times," 2d edit., p. 571. trefages, ''Unit^ de I'Espece Humaine," 

In this work (p. 571) there will be found an 1861, p. 21 etc 

excellent account of the many strange and " " PUssertation on Ethical Philosophy," 

capricious customs of savages. iSj'' ^p. 231, etc. 

* See, for instance, on this subject, (jua- 


law in the soivl, and so extorting for thyself always reverence, 
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- 
dependent interest, as an attempt to see how far tlie study of 
the lower animals throws light on one of the highest psychical 
faculties of man. 

The following proposition seems to me in a high degree 
probable — namely, that any animal whatever, endowed with 
well-marked social instincts,^ the parental and filial 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 in- 
dividuals of tjie same species, only to those of the same associa- 
tion. 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 ; 

* " Metaphysics of Ethics," translated the other acquired capacities above referred 

lily J. W. Semple, Edinbiirgh, 1836, p. 136. to, the moral faculty, if not a part of our 

■i Mr. Kain gives a list (" Menial and nature, is a natural outgrowth from it; ca- 
]\i;jral Science," 1868, pp. 543-725) of twenty- pable, like them, in a certain small degree, of 
six IJritish authors who have written on this sprintjing up spontaneously." But in op- 
subject, and whose names are famihar to position to all this, he also remarks, "if, as 
every reader ; to these, Mr. Bain's own is my own belief, the moral feelings are not 
name, and those of Mr. Lecky, Mr. Shad- innate, but acquired, they are not for that 
wortli Hodgson, Sir J. Lubbock, and others, reason less natural." It is with liesitation 
mi ;!. the added. that I venture to differ at all from so pro- 

^ Sir B. Brodie, after observing that man found a thinker, but it can hardly be dis- 

js a social animal ("Psychological Enquir- puted that the social feelings are instinctive 

ies," 1854, p. 192), asks the pregnant ques- or innate in the lower animals; and why 

tion, '' Ought not this to settle the disputed should they not be .so in mnn? Mr. Bain 

question as to the existence of a moral (see, for instance, "The l-lmotions and t!? 

sense?-' Similar ideas have probably oc- Will," 1865, p. 481) and others believe tli-.t 

curred to many persons, as they did long the moral sense is acquired by each intii- 

ago to Marcus Aurelius. Mr. J. S. Mill vidual durinjr his lifetime. On tlie general 

speaks, in his celebrated work, " Utilitari- theory ot evolution this is at least extremely 

anism" (1864, pp. 45, 46\ of the social feel- improbable. The ignoring of all transmitted 

ings as a "powerful natural sentiment," mental qualities will, as it seems to me. be 

and as " the natural basis of sentiment for hereafter judged as a most serious blemisll 

Utilitarian morality." Again he says, " Like in the works of Mr. Mill, 

114 "Tf^^^ DESCENT OF MAN. [PART t 

and that feeling of dissatisfaction, or even misery, which in- 
varial)ly results, as vvc shall hereafter see, Irom any unsatisfied 
instinct, would arise, as often as it was perceived that the en- 
during and always present social instinct had yielded to some 
other instinct, at the time stronger, but neither enduring in its 
nature nor leaving behind it a very vivid impression. It is 
clear that many instinctive desires, such as that of hunger, are 
in their nature of short duration ; and after being satisfied, are 
not readily or vividly recalled. Thirdly, after the power of 
language had been acquired, and the wishes of the community 
could be expressed, 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, however great weight we may attribute to publir 
opinion, our regard for the approbation and disapprobation of 
our fellows depends on sympathy, which, as we shall see, forms 
an essential part of the social instinct, and is indeed its founda- 
tion-stone. Lastly, habit in the individual would ultimately 
play a very important part in guiding the conduct of each 
member ; for the social instinct, together with sympathy, is, 
like any other instinct, greatly strengthened by habit, and so 
consequently would be obedience to the wishes and judgment 
of the community. These several subordinate propositions 
must now be discussed, and some of them at considerable 

It may be well first to premise that I do not wish to main- 
tain 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 con- 
ditions as hive-bees, there can hardly be a doubt that our un- 
married 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.^ 

• Mr. H. Sidgwick remarks, in an able male infanticide, polyandry, and promis- 

discussion on this subject fthe "Academy," cuous intercourse ; therefore it may well be 

June 15, 1872, p. 231). a superior bee. doubted whether it would be by a milder 

we may feel sure, would aspire to a milder method. Miss Cobbe, in commenting 

solution of the population question." Jndg- f" Dnrwini'^m in Morals," " Theoloo:icaJ 

ing, however, from the habits of many or Revirw." April. \?i-2. pp. iSf-igi) on the 

jRpst savages, roan solves the PToWem by fe- ^iwe UlustratiQ".. %ay&» V^^e prvKipUi •! 

ettAP. iv.l MORAL SENSE, I15 

Nevertheless, the bee, or any other social animal, would gain 
in our supposed case, as it appears to me, some feeling of righf 
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 fol- 
lowed ; and satisfaction, dissatisfaction, or even misery would 
he felt, as past impressions were compared during their incessant 
passage through the mind. In this case an inward monitor 
would tell the animal that it would have been better to have 
followed the one impulse rather than the other. The one 
course ought to have been followed, and the other ought not ; 
the one would have been right, and the other wrong ; but to 
these terms I shall recur. 

Sociability. — Animals of many kinds are social ; we find 
even distinct species living together ; for example, some 
American monkeys ; and united flocks of rooks, jackdaws, and 
starlings. Man shows the same feehng in his strong love for 
the dog, which the dog returns with interest. Everyone 
must have noticed how miserable horses, dogs, sheep, etc., are 
when separated from their companions, and what strong mutual 
affection the two former kinds, at least, show on their reunion. 
It is curious to speculate on the feelings of a dog, who will rest 
peacefully for hours in a room with his master or any of the 
family, without the least notice being taken of him ; but if left 
for a short time by himself, barks or howls dismally. We will 
confine our attention to the higher social animals ; and pass 
over insects, although some of these are social, and aid one an- 
other in many important ways. The most common mutual 
service in the higher animals is to warn one another of danger 
by means of the united senses of all. Every sportsman knows, 
as Dr. Jaeger remarks,"* how difficult it is to approach animals 
in a iierd 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. Rabbits stamp 
loudly on the ground with their hind feet as a signal ; sheep 
and chamois do the same with their forefeet, uttering likewise 

^ciai duty would be thus reversed ; and by advocated in this chapter were ever generally 

this, I presume, she means that the fulfil- accepted, "' I cannot but believe that in the 

tnent of a social duty would tend to the in- hour of their triumph would be sounded the 

jury of individuals ; but she overlooks the knell of the virtue of mankind ! " It is to 

fact, which she would doubtless admit, that be hoped that the belief in the permanence 

the instincts of the bee have been acq'iired of virtue on this earth is not held by niany 

for the good of the community. She goes persons on so weak a tenure. 

io fiu as to say that if the theory of <^ics "* ^' i>ie Darwin' sche Tbeorie,'* fc xtt. 

|I6 THE DESCENT OF MAN". Ipakt i. 

a whistle. Many birds, und some mammals, |X)St f^eiitincls, 
which in the Ccuse of seals are sauP generally U) he- the females. 
The leader of a troop of monkeys acts as the sentinel, and ut- 
ters cries expressive both of danger and of safety.'^ Social ani- 
mals perform many little services for each other ; horses nibl)le. 
and cows lick each other, on any spot which itches ; monkeys 
search each other for external parasites ; and Brehm states that 
after a troojj of the Cercopithecus griseo-viridis has rushed 
through a thorny brake, each monkey stretches itself on a 
branch, and another monkey sitting by, *' conscientiously " 
examines its fur, and extracts every thorn or bur. 

Animals also render more important services to one another ; 
thus wolves and some other beasts of prey hunt in packs, and 
aid one another in attacking their victims. Pelicans fish in 
concert. The Hamadryas baboons turn over stones to find in- 
sects, etc. ; and when they come to a large one, as many as can 
stand round turn it over together and share the booty. Social 
animals mutually defend each other. Bull bisons in North 
America, when there is danger, drive the cows and calves into 
the middle of the herd, while they defend the outside. I shall 
also in a future chapter give an account of two young wild bulls 
at Chillingham attacking an old one in concert, and of two 
stallions together trying to drive away a third staUion from a 
troop of mares. In Abyssinia, Brehm encountered a great troop 
of baboons, who were crossing a valley : some had already as- 
cended the opposite mountain, and some were still in the valley : 
the latter were attacked by the dogs, but the old males imme- 
diately 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 al! 
the baboons had reascended the heights, excepting a young one, 
about six months old, who, loudly caUing for aid, chmbed 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 triumphantly led him 
away — the dogs being too much astonished to make an attack. 
I cannot resist giving another scene which was-Avitnessed by this 
same naturalist : An eagle seized a young Cercopithecus, which, 
by clinging to a branch, was not at once carried off; it cried 

fi Mr. R. Brown in " Proc. Zoolog. Soc.," the fact is given (s. 76) on the evidence cl 

1868. p 409. Alvarez, whose observations Brehm thinks 

^ Brehm, "Thierleben," B. i., 1864, s. 52, quite trustworthy. For the cases of the old 

79. For the case of the monkeys extracting male baboons attacking the dogs, see s. 79 

thorns from each other, see s. 54. With re- and with respect to the eagle, s. 56 
spect to Uie Hamadryas turning over stones. 


loudly for assistance, upon whicli the other members of the 
troop, with much uproar, rushed to the rescue, surrounded the 
eagle, and pulled out so many feathers that he no longer thought 
of his prey, but only how to escape. This eagle, as Brehm 
remarks, assuredly would never again attack a single monkey 
of a troop. ^^ 

It is certain that associated animals have a feeling of love for 
each other which is not felt by non-social adult animals. How 
far in most cases they actually sympathize in the pains and 
pleasures of others, is more doubtful, especially with respect to 
pleasures. Mr. Buxton, however, who had excellent means of 
observation,^^ states that his macaws, which lived free in Norfolk, 
took *'an extravagant interest" in a pair with a nest; and 
whenever the female left it, she was surrounded by a troop 
** screaming horrible acclamations in her honor." It is often 
difficult to judge whether animals have any feeling for the suffer- 
ings of others of their kind. Who can say what cows feel, when 
they surround and stare intently on a dying or dead companion ; 
apparently, however, as Houzeau remarks, they feel no pity. 
That animals sometimes are far from feeling any sympathy is too 
certain ; for they will expel a wounded animal from the herd, 
or gore or worry it to death. This is almost the blackest fact 
in natural history, unless, indeed, the explanation which has 
been suggested is true, that their instinct or reason leads them 
to expel an injured companion, lest beasts of prey, including 
man, should be tempted to follow the troop. In this case their 
conduct is not much worse than that of the North American 
Indians, who leave their feeble comrades to perish on the plains : 
cr the Fijians, who, when their parents get old, or fall ill, bury 
them alive. ^^ 

Many animals, however, certainly sympathize with each 
other's distress or danger. This is the case even with birds. 
Captain Stansbury ^"^ found on a salt lake in Utah an old and 
completely blind pelican, which was very fat, and must have 
been well fed for a long time by his companions. Mr. Blyth, 

'" Mr. Belt gives the case of a spider- " "Annals and Mag. of Nat. Hist.,"No- 

monke.y (Ateles) in Nicaragua, which was vember, 1868, p. 382. 

heard .screaming for nearly two hours in the ^^ Sir J. Lubbock, " Prehistoric Times,** 

forest, and was found with an eagle perched 2d edit., p. 446. 

close by it. The bird apparently feared to " As quoted by ^Ir. L. H. Morgan, "The 

arrark as long as it remained face to face ; American Beaver," 1868, p. 272. Captain 

and Mr. Belt believes, from what he has Stnnsbury gives an interesting account 

seen of the habits of these monkeys, that of the manner in which a ver>' young pelican, 

tlicy protect thetnselves from eagles by keep- carried away by a strong stream, was 

ing two or three together. "The Naturalist guided and encouraged in its attempts to 

fe Nicaragua," 1874, p. 118. reach the shore by half a dozen old birds. 


as he informs me, saw Indian crows feeding two or three ol 
their companions which were Wind ; and I have heard of v^ 
analogous case with the domestic cock. We may, if we choose, 
call these actions instinctive ; but such cases are much too rare 
for the development of any special instinct.^* I have myself 
seen a dog who never passed a cat who lay sick in a basket, 
md was a great friend of his, without giving her a few hcks 
with his tongue, the surest sign of kind feeling in a dog. 

It must be called sympathy that leads a courageous dog to 
fly at any one who strikes his master, as he certainly will. I 
saw a person pretending to beat a lady, who had a very timid 
little dog on her lap, and the trial had never been made before ; 
the little creature instantly jumped away, but after the pretended 
beating was over, it was really pathetic to see how persever- 
ingly he tried to lick his mistress's face, and comfort her. 
Brehm^^ states that when a baboon in confinement was pur- 
sued 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 Zoo- 
logical Gardens showed me some deep and scarcely healed 
wounds on the nape of his own neck, inflicted on him, while 
kneeling on the floor, by 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 frien-d in peril, he 
rushed to the rescue, and by screams and bites so distracted the 
baboon that the man was able to escape, after, as the surgeon 
thought, running great risk of his life. 

Besides love and sympathy, animals exhibit other qualities 
connected with the social instincts, which in us would be 
called moral; and I agree with Agassiz^^ that dogs possess 
something very like a conscience. 

Dogs possess some power of self-command, and this does not 
appear to be wholly the result of fear. As Braubach ^^ remarks, 
they will refrain from stealing food in the absence of their 
master. They have long been accepted as the very type of 
fidelity and obedience. But the elephant is likewise very faith- 

1* As Mr. Bain states, " effective aid to a '• " De PEsp&ce et de la Classe," 1869^ 

sufferer springs from sympathy proper : " p. 97. 

** Mental and Moral Science," 1868, p. 245. " " Die Darwin'sche Art-Lehrc»* xM^ 

i» "Tkierleben." B. i, s. 85. 8. 54- 


ful to Vj dri/er or keeper, and probably considers him as the 
LQ.2J^lx of the herd. Dr. Hooker informs me that an elephant 
rhich he was riding in India became so deeply bogged that he 
remained stuck fast until the next day, when he was extricated 
by men with ropes. Under such circumstances elephants will 
seize with their trunks any object, dead or alive, to place under 
their knees, to prevent their sinking deeper in the mud ; and the 
driver was dreadfully afraid lest the animal should have- seized 
Dr. Hooker and crushed him to death. But the driver himself, 
as Dr. Hooker was assured, ran no risk. This forbearance, 
under an emergency so dreadful for a heavy animal, is a wonder- 
ful proof of noble fidelity. ^^ 

All animals living in a body, which defend themselves or at- 
tack 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. Mr. Galton, 
who has had excellent opportunities for observing the half- 
wild cattle in South Africa, says,^ that they cannot endure even 
a momentary separation from the herd. They are essentially 
slavish, and accept the common determination, seeking no 
better lot than to be led by any one ox who has enough self- 
reliance to accept the position. The men who break in these 
animals for harness watch assiduously for those who, by graz- 
ing apart, show a self-reliant disposition, and these th3y train 
as fore-oxen. Mr. Galton adds that such animals are rare and 
valuable ; and if many were born they would soon be elimi- 
nated, as lions are always on the lookout for the 'ndividuaJs 
which wander from the herd. 

With respect to the impulse which leads certain animals to 
associate together, and to aid one another in many ways, we 
may infer that in most cases they are impelled by the same 
sense of satisfaction or pleasure which they experience in per- 
forming other instinctive actions ; or by the same sense of 
dissatisfaction as when other instinctive actions are checked. 
We see this in innumerable instances, and it is illustrated in a 
striking manner by the acquired instincts of our domesticated 
animals ; thus a young shepherd- dog delights in driving and 

** See also Hooker's " Himalayan Jour- '" See his extremely interesting paper oo 
Dais," vol. ii., 185-^, p. 333. *• Gregariousness in Cattle, and in Man,* 

** Brehm. "Thierleben," Br L s. 76. *' Mactnillan's Mag.," Feb., 1871, p. 353. 


running round a flock of sheep, but not in worrying them ; a 
young fox-hound delights in hiniting a fox, while some other 
kinds of dogs, as I have witnessed, utterly disregard foxes. 
What a strong feeling of inward satisfaction must impel a bird, 
so fidl of activity, to brood day after day over her eggs. 
Migratory birds are quite miseral)le if stopped from migrating; 
perhaps they enjoy staiting on their long flight ; but it is hard 
to beliete that the poor pinioned goose, described by Audubon, 
which started on foot at the proper time for its journey of prob- 
ably more than a thousand miles, could have felt any joy in 
doing so. Some instincts are determined solely by painful 
feelings, as by fear, which leads to self-preservation, and is in 
some cases directed toward special enemies. No one, I pre- 
sarr.e, can analyze the sensations of pleasure or pain. In many 
instances, however, it is probable that instincts are persistently 
followed from the mere force of inheritance, without the 
stimulus of either pleasure or pain. A young pointer, when 
it first scents game, apparently cannot help pointing. A 
squirrel in a cage who pats the nuts which it cannot eat, as i! 
to bury them in the ground, can hardly be thought to act 
thus either from pleasure or pain. Hence the common as- 
sumption that men must be impelled to every action by ex- 
periencing some pleasure or pain may be erroneous. Although 
a habit may be blindly and implicitly followed, independently 
of any pleasure or pain felt at the moment, yet if it be forcibly 
and abruptly checked, a vague sense of dissatisfaction is gener- 
ally experienced. 

It has often been assumed that animals were in the first place 
rendered social, and that they feel as a consequence uncom- 
fortable when separated from each other, and comfortable 
while together ; but it is a more probable view that these sen- 
sations 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 sease of hunger and the 
pleasure of eating were, no doubt, first acquired in order 
to induce animak to eat. The feeling of pleasure from society 
is probably an extension of the parental or filial affections, since 
the social instinct seems to be developed by the young remain- 
ing for a long time with their parents ; and this extension may 
be attributed in part to habit, but chiefly to natural selection. 
With those animals which were benefited by living in close 
association, the individuals which took the greatest pleasure 
in society would best escape various dangers ; while those that 


Cflied least for their comrades, aiid lived solitary, v^ould perish 
in greater numbers. With respect to the origin of the parental 
and filial affections, which apparently lie at the base of the 
social instincts, we know not the stejjs by which they have 
been gained ; but we may infer that it has been to a large 
extent tlirough natural selection. So it has almost certainly 
been with the unusual and opposite feeling of hatred between 
the nearest relations, as with the worker-bees which kill theii 
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 feehng which replaces it, has been developed 
in certain animals extremely low in the scale, for example, in 
star-fishes and spiders. It is also occasionally present in a 
few members alone in a whole group of animals, as in the genus 
Forficula, or earwigs. 

The all-important emotion of sympathy is distinct from that 
of love. A mother may passionately love her sleeping and 
passive infant, but she can hardly at such times be said to feel 
sympathy for it. The love of a man for his dog is distinct 
from sympathy, and so is that of a dog for his master. Adam 
Smith formerly argued, as has Mr. Bain recently, that the basis 
of sympathy lies in our strong retentiveness of former states of 
pain or pleasure. Hence, ** the sight of another person endur- 
ing hunger, cold, fatigue, revives in us some recollection ol 
these states, which are painful even in idea." We are thus 
impelled to relieve the sufferings of another, in order that our 
own painful feelings may be at the same time relieved. In like 
manner we are led to participate in the pleasures of others. '^^ 
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 suf^ce to call up in us vivid recol- 
lections and associations. The explanation may lie in the 
fact that, with all animals, sympathy is directed solely toward 
the members of the same community, and therefore toward 
known and more or less beloved members, but not to all the 

•i Sec the first and striking chapter in benefited, or others In his stead, may make 

Adam Smith's "Theory of Moral Senti- up, by sympathy and good offices retumeo, 

ments." ^ Also Mr. Bain's *' Mental and for all the sacrifice." But if, as appears to 

Moral Science," 1868, pp. 244 and 275-282. be the case, sympathy is strictly an instinct, 

Mr. Ba"^ JtXL^Ei \hat " sympathy is, indi- its exercise wonld give direct pleasure, io 

rect'7, a source oi ^,^-( *o the sympa- the same manner as the exercise, as before 

U)izer;" and he accounts for Ais through remarked, of almost every otlier instinct. 
dW%rocity. He remarks that "the person 

(Fj— V0U8; 

122 THE DESCENT OF MAN. [part I, 

individuals of the same species. This fact is not more sur- 
prising than that the fears of many animals should l)e directed 
against special enemies. Species which are not social, such as 
hons and tigers, no doubt feel sympathy for the suffering of 
their own young, but not for that of any other animal. With 
mankind, selfishness, experience, and imitation probably add, 
as Mr. Bain has shown, to the power of sympathy ; for we 
are led by the hope of receiving good in return to perform 
acts of sympathetic kindness to others ; and sympathy is much 
strengthened by habit. In however complex a manner this 
feeling may have originated, as it is one of high importance to 
all those animals which aid and defend one another, it will 
have been increased through natural selection ; for those com- 
munities which included the greatest number of the most 
sympathetic members would flourish best, and rear the greatest 
number of offspring. 

It is, however, impossible to decide in many cases whether 
certain social instincts have been acquired through natural 
selection, or are the indirect result of other instincts and 
faculties, such as sympathy, reason, experience, and a ten- 
dency to imitation ; or again, whether they are simply the 
result of long-continued habit. So remarkable an instinct as 
the placing sentinels to warn the community of danger can 
hardly have been the indirect result of any of these faculties ; 
it must, therefore, have been directly acquired. On the other 
hand, the habit followed by the males of some social animals 
of defending the community, and of attacking their enemies 
or their prey in concert, may perhaps have originated from 
mutual sympathy ; but courage, and in most cases strength, 
must have been previously acquired, probably through natural 

Of *:h2 various instincts and habits, some are much stronger 
than others ; that is, some either give more pleasure in their 
performance, and more distress in their prevention, than others ; 
or, which is probably quite as important, they are, through 
inheritance, more persistently followed, without exciting any 
special feeling of pleasure or pain. We are ourselves conscious 
that some habits are much more difficult to cure or change than 
others. Hence a struggle may often be observed ' in animals 
between different instincts, or between an instinct and some 
habitual disposition ; as when a dog rushes after a hare, is 
rebuked, pauses, hesitates, pursues again, or returns ashamed to 
his master; or as between the love of a female dog for her 


young puppies and for her master — for she may be seen to 
sHnk away to them, as if half-ashamed of not accompanying 
her master. But the most curious instance known to me of 
one instinct getting the better of another, is the migratory 
instinct conquering the maternal instinct. The former is won- 
derfully strong ; a confined bird will at the proper season beat 
her breast against the wires of her cage, until it is bare and 
bloody. It causes young salmon to leap out of the fresh water, 
in which they could continue to exist, and thus unintentionally 
to commit suicide. Everyone 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-preser- 
vation. Nevertheless, 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 opposed 
instinct, would be rendered the more potent of the two through 
natural selection ; for the individuals which had it most strongly 
developed would survive in larger numbers. Whether this is 
the case with the migratory in comparison with the maternal 
instinct, may be doubted. The great persistence or steady 
action of the former at certain seasons of the year, during the 
whole day, may give it for a time paramount force. 

Man a Social Animal. — Everyone 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 in- 
flicted. 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 oom- 

" This fact, the Rev. L. Jenyns states birds, not yet old enough for a prolonged 

(see his edition of " White's Nat. Hist, of flight, are likewise deserted and left behind. 

Selbome," 1853, P- 204) was first recorded See Ulackwall, " Researches in Zoology," 

by the illuRtrious Jenncr, in "'Phil. 'IVans- 18^4, pp. 108, 118 For some additional 

act.," 1824, and has since been confirmed evidence, although this i"? not wanted, see 

by several observers, especially by Mr. Leroy, " Lettres Phil.," 1802. p. 217. Koi 

Blackwall. This latter careful observer ex- swifts. Gould's *' Introduction to the Kirds 

amined, late in the autumn, during two of Great Britain," 1^23. d. 5. Similar cases 

years, thirty-six nests ; he found that hrtve been observed in Canada by Mr. 

twelve contamed young dead birds, iive con- Adams ; " Pop. Science Review," July, 

tained eggs on the pomt of being hatched, 1873, p. 283. 
Mid three, eggs not nearly hatched. Many 

124 THh DliSCENT Oh MAh^ D'AitT t. 

mon defence. It is no argument df^ainst savage rnan being a 
social animal that the tribes inhabiting adjacent districts are 
ahnost always at war with each other; for the social instincts 
never extend to all the individuals of the same species. Judg- 
ing from the analogy of the majority of the Quadrumana, it is 
probable that the early ape-like progenitors of man were like- 
wise social ; but this is not of much importance for as. Although 
man, as he now exists, has few special instincts, having lost any 
which his early progenitors may have possessed, this is no rea- 
son why he should not have retained from an extremely remote 
period some degree of instinctive love and sympathy for his 
fellows. We are indeed all conscious that we do possess such 
sympathetic feelings ; ^ but our consciousness does not tell us 
whether they are instinctive, having originated long ago in the 
same manner as with the lower animals, or whether they have 
been acquired by each of us during our early years. As man is a 
social animal, it is almost certain that he would inherit a ten- 
dency to be faithful to his comrades, and obedient to the leader 
of his tribe, for these qualities are common to most social 
animals. He would consequently possess some capacity for 
self-command. He would from an inherited tendency be will- 
ing 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 de- 

The social animals which stand at the bottom of the scale are 
guided almost exclusively, and those which stand higher in the 
scale are largely guided, by special instincts in the aid which 
they give to the members of the same community ; but they 
are likewise in part impelled by mutual love and sympathy, as- 
sisted 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 im- 
proved intellectual faculties would naturally be much guided in 
this^ respect by reason and experience. Instinctive sympathy 
would also cause him to value highly the approbation of his 
fellows; for, as Mr. Bain has clearly shown, ^^ the love of praise 
and the strong feeling of glory, and the still stronger horror of 
scorn and infamy, *'are due to the workings of sympathy.'* 

'^ Hume remarks ("An Enquiry Con- . . . communicates a secret joy ; the ap* 

cerning the Principles ol Morals," edit, of pearance of the latter . . . throws a 

175^1 P- ^32), "There seems a necessity for melancholy damp over the imagination." 
confessing that the happiness and misery of 24 «« Mental and Morai Science," 1868, pb 

Others are not spectacles altogether indiffer- 2=4. 
eat to us» but that the view of the former 


Consequently man would be influenced in the highest degree 
by the wishes, ai)probation, 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 of his fellow-men, and, unfortunately, very often by 
his own strong, selfish desires. But as love, sympathy, and s^elt- 
command become strengthened by habit, and as the pov/ei of 
reasoning becomes clearer, so that man can value jubtly the 
judgments of his fellows, he will feel himself impelled, apart 
from any transitory pleasure or pain, to certain lines, of con- 
duct. He might then declare — not that any barbaiian or un- 
cultivated man could thus think — I am the suprcrme judge of 
my own conduct, and, in the words of Kant, I will not in my 
own person violate the dignity of humanity. 

The more enduring Social Instincts conquer t^te less persistent 
Instincts. — We have not, however, as yet couaiaered the main 
point on which, from our present point oi view, the whole 
question of the moral sense turns. Why should a man feel that 
he ought to obey one instinctive desire rather than another ? 
Why is he bitterly regretful, if he has yielded to a strong sense 
of self-preservation, and has not risked ols life to save that of a 
fellow-creature? or why does he regre^ having stolen food from 
hunger ? 

It is evident, in the first place, thu'. with mankind the instinc- 
tive impulses have different degrees of strength ; a savage will 
risk his own life to save that of a member of the same com- 
munity, but will be wholly indifferent about a stranger ; a 
young and timid mother, urged by the maternal instinct, will, 
without a moment's hesitatior^, run the greatest danger for her 
own infant, but not for a mste fellow-creature. Nevertheless 
many a civilized man, or e^en boy, who never before risked 
his life for another, but, full of courage and sympathy, has dis- 
regarded the instinct of self-preservation, and plunged at once 
into a torrent to save a drowning man, though a stranger. In 
this case man is impelled by the same instinctive motive which 
made the heroic little American monkey, formerly described, 
save his keeper, by attacking the great and dreaded baboon. 
Such actions as the above appear to be the simple result of the 
greater strength of the social or maternal instincts than that of 
any other instinct or motive \ for they are performed too in," 

126 THE DESCENT OF MAI^. (part t 

stantaneously for reflection, or for pleasure or pain to be felt 
at the time; though, if prevented by any cause, distress or even 
misery might ])e 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 
dominion of the moral sense, and cannot be called moral. They 
confine this term to actions done deliberately, after a victory 
over opposing desires, or when prompted by some exalted 
motive. But it appears scarcely possible to draw any clear line 
of distinction of this kind.^ As far as exalted motives are con- 
cerned, many instances have been recorded of savages, destitute 
of any feeling of general benevolence toward mankind, and not 
guided by any religious motive, who have deliberately sacrificed 
their lives as prisoners,^ 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, we all feel that an act cannot be considered ac 
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 per- 
formed by a moral being. A moral being is one who is capa- 
ble of comparing his past and future actions or motives, and of 

'• I refer here to the distinction between between material and formal morality is as 

what has been called material zxiA fortnal irrelevant as other such distinctions." 

morality. I am glad to find that Prof. Hux- "* I have given one such case, namely, of 

ley (" Critiques and Addresses," 1873, p. three Patasjonian Indians who preferred be- 

»87) takes the same view on this subject as ing shot, one after the other, to betraying 

I do. Mr. Leslie Stephen remarks (" Es- the plans of their companions in wat 

says on Freethinking and Plain Speaking," (" Journal of Researches," 1845, p. lojjr 
1S731 P' 83}, " the metaphysical distinction 

CHAP, rv.l MORAL SENSE. 12/ 

approving or disapproving of them. We have no reason to 
suppose that any of the lower animals have this capacity ; 
therefore, when a Newfoundland dog drags a child out of the 
water, or a monkey faces danger to rescue its comrade, or takes 
charge of an orphan monkey, we do not call its conduct moral. 
But in the case of man, who alone can with certainty be ranked 
as a moral being, actions of a certain class are called moral, 
whether performed deliberately, after a struggle with opposing 
motives, or impulsively through instinct, or from the effects of 
slowly gained habit. 

But to return to our more immediate subject. Although 
some instincts are more powerful than others, and thus lead to 
corresponding actions, yet it is untenable that in man the so- 
cial 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, etc. Why then does man regret, even though 
trying to banish such regret, that he has followed the one natu- 
ral impulse rather than the other; and why does he further 
feel that he ought to regret his conduct ? Man in this respect 
differs profoundly from the lower animals. Nevertheless we 
can, I think, see with some degree of clearness the reason of 
this difference. 

Man, from the activity of his mental faculties, cannot avoid 
reflection ; past impressions and images are incessantly and 
clearly passing through his mind. Now with those animals 
which live permanently in a body, the social instincts are ever 
present and persistent. Such animals are always ready to utter 
the danger-signal, to defend the community, and to give aid to 
their fellows in accordance with their habits ; they feel at all 
times, without the stimulus of any special passion or desire, 
some degree of love and sympathy for them ; they are unhappy 
if long separated from them, and always happy to be again in 
their company. So it is with ourselves. Even when we are 
quite alone, how often do we think with pleasure or pain of 
what others think of us — of their imagined approbation or dis- 
approbation ; and this all follows from sympathy, a fundamen- 
tal 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 bo 
fully satisfied. Nor is it easy, perhaps hardly possible, to call 
up with complete vividness the feeling, for instance, of hunger ^ 


nor indeed, as has often been remarked, oi any suffering. The 
inslinct of self-preservation is not felt excej t u\ the presence of 
danger; and many a coward has thouglit himself brave until 
he has met his enemy face to face. The wish for another 
man's property is perhaps as persistent a desire as any that can 
be named ; but even in this case the satisfaction of actual pos- 
session is generally a weaker feeling than the desire : many a 
thief, if not an habitual one, after success has wondered why he 
stole some article.'^ 

A man cannot prevent past impressions often repassing 
Jhrough his mind ; he will thus be driven to make a compari- 
son between the impressions of past hunger, vengeance satisfied, 
or danger shunned at other men's cost, with the almost ever- 
present instinct of sympathy, and with his early knowledge of 
what others consider as praiseworthy or blamable. This 
knowledge cannot be banished from his mind, and from in- 
stinctive sympathy is esteemed of great moment. He will 
then feel as if he had been balked in following a present in- 
stinct or habit, and this with all animals causes dissatisfaction, 
or even misery. 

The above case of the swallow affords an illustration, though 
of a reversed nature, of a temporary, though for the time 
strongly persistent, instinct conquering another instinct which 
is usually dominant over all others. At the proper season 
these birds seem all day long to be impressed with the desire 
to migrate; their habits change; they become restless, are 
noisy, and congregate in flocks. While the mother-bird is 
feeding, or brooding over her nesthngs, the maternal instinct 
is probably stronger than the migratory ; but the instinct 
which is the more persistent gains the victory, and at last, at a 
moment when her young ones are not in sight, she takes flight 
and deserts them. When arrived at the end of her long jour 

'^ Enmity or hatred seems also to be a small step in anyone to transfer such feel* 

highly persistent feehng, perhaps more so ings to any member of the same tribe if he 

ihan any other that can be named. Envy is had done him an injury and had become his 

defined as hatred of another for some excel- enem.y. Nor is it probable that the primi- 

lenceor success ; and Bacon insists (Essay live conscience would reproach a man forin- 

ix.), " Of all other affections envy is the juring his enemy : rather it would reproach 

most importune and contmiial." Dogs are him if he had not revenged himself. To do 

very apt to hate both strange men and good in return for evil, to love your enemy, 

strange dogs, especially if they live near at is a height of morality to which it may be 

hand, but do not belong to the same family, doubted whether the social instincts would, 

tribe, or clan ; this feeling would thus seem by themselves, have ever led us. It is nec- 

to be innate, and is certainly a most persist- essary that these instincts, together with 

ent one. It seems to be the complement and sympathy, should have been highly cu'ti- 

converse of the true social mstmct. From vatcd and extended by the aid of reason, 

what we hear of savages, it would appear instruction, and the love or fear of God, be- 

ihat something of the same kind holds good fore any such golden rule would erer b« 

nrith tbem. If this be so, it would be a thought of and obeyed. 

CHAP, iv.l MORAL SENSE. - 129 

ney, and the migratory instinct has ceased to act, what an 
agony of remorse the bird would feel, if, from bein^ endowed 
with great mental activity, she could not prevent the image 
constantly passing through her mind, of her young ones perish- 
ing in the bleak north from cold and hunger. 

At the moment of action man will no doubt be apt to fol- 
low 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, re- 
gret, or shame ; this latter feeling, however, relates almost ex- 
clusively to the judgment of others. He will consequently re- 
solve more or less firmly to act differently for the future ; and 
this is consci ince ; for conscience looks backward, and serves 
as a guide for the future. 

The nature and strength of the feelings which we call regret, 
shame, repentahce, 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 cur 
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 re- 
mote consequences of his acts. Another element is most im- 
portant, although not necessary — the reverence or fear of th6 
Gods or Spirits believed in by each man ; and this applies 
.especially in cases of remorse. Several critics have objected 
that, though some slight regret or repentance may be explained 
by the view advocated in this chapter, it is impossible thus to ac- 
count for the soul-shaking feeling of remorse. But I can see lit- 
tle 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. Remorse seems to 
.bear the eame relation to repentance as rage does to anger, or 
agony to pain. It is far from strange that an instinct so strong 
and so generally admired as maternal love should, if dis- 
obeyed, lead to the deepest misery, as soon as the impression 
of the past cause of disobedience is weakened. Even when an 
action is opposed to no special instinct, merely to know that 
our friends and equals despise us for it is enough to cause great 
misery. Who can doubt that the refusal to flight a duel 


through fear has caused many men an agony of shame ? Many 
a Hindoo, it is said, has been stirred to the bottom of his soui 
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 losmg one of his wives from disease, came and 
said that *' he was going to a distant tribe to spear a woman, 
to satisfy his sense of duty to his wife. I told h.'m that if he 
did so, I would send him to prison for Hfe. He remained 
about the farm for some montlis, but got exceedingly thin, 
and complained that he could not rest or eat, that his wife's 
spirit was haunting him, because he had not taken a life for 
hers. I was inexorable, and assured him that nothing should 
•ave 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 im- 
possible 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 supersti- 
tions have arisen throughout the world we know not ; nor can 
we tell how some real and great crimes, such as incest, have 
come to be held in an abhorrence (which is not however quite 
universal) by the lowest savages. It is even doubtful whether 
in some tribes incest would be looked on with greater horror 
than would the marriage of a man with a woman bearing the 
same name, though not a relation. ** To violate this law is a 
crime which the Australians hold in the greatest abhorrence, in 
this agreeing exactly with certain tribes of North America. 
When the question is put in either district, is it worse to kill a 
girl of a foreign tribe or to marry a girl of one's own, an an- 
swer just opposite to ours 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 
I special God-implanted conscience. On the whole it is in- 
telligible that a man urged by so powerful a sentiment as re- 
morse, though arising as above explained, should be led to act 
in a manner which he has been taught to believe serves as an 
expiation, such as delivering himself up to justice. 

«•" Insanity in Relaiion to Law ; " On- ''^ F. B. Tylor in " Contemporary *•» 
luk), United States, 1871, p. 14. view," April, 1873, p. jvj. 


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 
synipathies 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 comes to feel, through acquired and perhaps 
inherited habit, that it is best for him to obey his more per- 
sistent impulses. The imperious word ought seems merely to 
imply the consciousness of the existence of a rule of conduct, 
however it may have originated. Formerly it must have been 
often vehemently urged that an insulted gentleman ought to 
fight a duel. We even say that a pointer ought to point, and 
a retriever to retrieve game. If they fail to do so, they fail 
in their duty, and act wrongly. 

If any desire or instinct leading to an action opposed to the 
good of others still appears, when recalled to mind, as strong 
as, or stronger than, the social instinct, a man will feel no 
keen regret at having followed it ; but he will be conscious that 
if his conduct were known to his fellows, it would meet with 
their disapprobation ; and few are so destitute of sympathy as 
not to feel discomfort when this is realized. If he has no such 
sympathy, and if his desires leading to bad actions are at the 
time strong, and when recalled are not overmastered by the 
persistent social instincts and the judgment of others, then he 
is essentially a bad man ; ^ and the sole restraining motive left 
is the fear of punishment, and the conviction that in the long 
run it would be best for his own selfish interests to regard the 
good of others rather than his own. 

It is obvious that everyone may with an easy conscience 
gratify his own desires, if they do not interfere with his social 
instincts, that is with the good of others ; but in order to be 
quite free from self-reproach, or at least of anxiety, it is almost 
necessary for him to avoid the disapprobation, whether reason- 
able 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 

•" Dr. Prosper Despiiie, in his " Psychol- worst criminals, who apparently have ^kcq 
Ogie Naturelle," i8j8 (torn. i. p. 243 ; torn, eiuirely destitute of conscience, 
f\. p. 169} gives many curious ca^es of (he 

132 T/rii DESCENT OF MAN', (part L 

in whom, according to his knowledge or superstition, he may 
believe; but in this case the additional fear of divine punish- 
ment often supervenes. 

The strictly Social Virtues at first alone regarded. — The 
above view of the origin and nature of the moral sense, which 
tells us what we ought to do, and of the conscience which re- 
proves us if we disobey it, accords well with what we see of 
the early and undeveloped condition of this faculty in man- 
kind. The virtues which must be practised, at least generally, 
by rude men, so that they may associate in a body, are those 
which are still recognized as the most important. But they are 
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 othcx tribes. No tribe could hold together if 
murder, robbery, treachery, etc., were common; consequently 
such crimes within the limits of the same tribe ''are branded 
with everlasting infamy ; " ^^ but excite no such sentiment be- 
yond these limits. A North American Indian is well pleased 
with himself, and is honored by others, when he scalps a man 
of another tribe ; and a Dyak cuts off the head of an unoffend- 
ing person, and dries it as a trophy. The murder of infants 
has prevailed on the largest scale throughout the world,^ and 
has met with no reproach ; but infanticide, especially of fe- 
males, has been thought to be good for the tribe, or at least not 
injurious. Suicide during former times was not generally con- 
sidered as a crime,^ but rather, trom the courage displayed, as 
an honorable act ; and it is still practised by some semi-civil- 
ized and savage nations without reproach, for it does not ob- 
viously concern others of the tribe. It has been recorded that 
an Indian Thug conscientiously regretted that he had not 
robbed and strangled as many travellers as did his father before 
him. In a rude state of civilization the robbery of strangers 
is, indeed, generally considered as honorable. 

Slavery, although in some ways beneficial during ancient 

•' See an able article in the " North British Suicide in Lecky's " History of European 

Review," 1867, p. 395. See also Mr. W. Morals," vol. i., 1869, p. 223. With respect 

Bagehot's articles on the Importance of to savages, Mr. Winwood Reade inrorms 

Obedience and Coherence to Primitive me that the negroes of West Africa of.en 

Man, in the " Fortnighdy Review," 1S67, p. commit suicide. It is well known how com- 

529, and 1868, p. 457, etc. mon it was among the miserable aborigines 

'" The fullest account which I have met of South America, after the Spanish con- 

Wfith is by Dr. Gerland, in his " Ueber das quest. For New Zealand, see the voyage 

Aussterben der Naturvolker," 1868 ; but I of the Novara, and for the Aleutian 

shall have to recur to the subject of infanti- Islands, Miiller, as quoted by Houzeau, 

«ide in a future chapter. " Les Facultds Mentales,'* etc., torn. ii. pb 

*3 See the very interesting discussion on 136^, 


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 indifferent to the suffer- 
ings of strangers, or even delight in witnessing them. It is well 
known that the women and children of the North American 
Indians aided in torturing their enemies. Some savages take a 
horrid pleasure in cruelty to animals,^ and humanity is an 
unknown virtue. Nevertheless, besides the family affections, 
kindness is common, especially during sickness, between the 
members of the same tribe, and is sometimes extended beyond 
these Hmits. Mungo Park's touching account of the kindness 
of the negro women of the interior to him is well known. 
Many instances could be given of the noble fidelity of savages 
toward each other, but not to strangers ; common experience 
justifies the maxim of the Spaniard, " Never, never trust an 
Indian." There cannot be fidehty without truth ; and this 
fundamental virtue is not rare between the members of the 
same tribe : thus Mungo Park heard the negro women teacning 
their young children to love the truth. This, again, is one oi 
the virtues which becomes so deeply rooted in the mind that 
it is sometimes practised by savages, even at a high cost 
toward strangers ; but to lie to your enemy has rarely been 
thought a sin, as the history of modern diplomacy too piainly 
shows. As soon as a tribe has a recognized leader, disobedi- 
ence becomes a crime, and even abject submission is looked at 
as a sacred virtue. 

As during rude times no man can be useful or faithful to his 
tribe without courage, this quality has universally been placed 
in the highest rank ; and although in civilized countries a good 
yet timid man may be far more useful to the community than 
a brave one, we cannot help instinctively honoring 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 

w See Mr. Bagehot, " Physics and PoU- count of the Kaffirs, *' Amhrof^>Iogical 
tics." 1872, p. 72. Review," 1870, p. xv. 

*" See, for instance, Mr. Hamilton's ac* 

134 THE DESCENT OF MA^T, lifhrx-r •, 


most justly valued. The American savage voluntarily submits 
to the most horrid tortures 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 h) 

The other so-called self-regarding virtues, which do not ob« 
viously, though they may really, affect the welfare of the tril)e, 
have never been esteemed by savages, though now highly 
appreciated by civilized nations. The greatest intemperance 
is no reproach 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 honored, will tend to spread to the un- 
married females. How slowly it spreads to the male sex, we 
see at the present day. Chastity eminently requires self-com- 
mand ; therefore it has been honored from a very early period 
in the moral history of civilized man. As a consequence of 
this, the senseless practice of celibacy has been ranked from a 
remote period as a virtue.^^ The hatred of indecency, which 
appears to us so natural as to be thought innate, and which is 
so valuable an aid to chastity, is a modern virtue, appertaining 
exclusively, as Sir G. Staunton remarks,^ to civilized life. This 
is shown by the ancient religious rites of various nations, by the 
drawings on the walls of Pompeii, and by the practices of many 

We have now seen that actions are regarded by savages, and 
were probably so regarded by primeval man, as good or bad, 
3olely as they obviously affect the welfare of the tribe — not that 
of the species, nor that of an individual member of the tribe. 
This conclusion agrees well with the belief that the so-called 
moral sense is aboriginally derived from the social instincts, for 
both relate at first exclusively to the community. The chief 
causes of the low morality of savages, as judged by oui stand- 
ard, are, firstly, the confinement of sympathy to the same 
tribe. Secondly, powers of reasoning insufficient to recognize 
the bearing of many virtues, especially of the self-regarding 
virtues, on the general welfare of the tribe. Savages, for in- 
stance, fail to trace the multiplied evils consequent on a want 

'•Mr. M'Lennan has given ("Primitive '"^ Lecky, "History of European Morals,^ 
Marriage,'' 1865, p. 176) a good collection of vol. i., 1869, p. log. 
facts on this head= °s »• Kmb^ssv to China," vol. U. p. 34Sk 


of temperance, chastity, etc. And, thirdly, weak power of 
self command ; for this power has not been strengthened 
through long-continued, perhaps inherited, habit, instruction, 
and religion. 

I have entered into the above details on the immorality of 
savages,^ because some authors have recently taken a high 
view of their moral nature, or have attributed most of their 
crimes to mistaken benevolence.'^ These authors appear to 
rest their conclusion on savages possessing those virtues which 
are serviceable, or even necessary, for the existence of the 
family and of the tribe — qualities which they undoubtedly do 
possess, and often in a high degree. 

Concluding Remarks. — It was assumed formerly by philos- 
ophers 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 exceptions, '^^ write as if there must be a distinct 
motive for every action, and that this must be associated with 
some pleasure or displeasure. But man seems often to act im- 
pulsively, that is from instinct or long habit, without any con- 
sciousness of pleasure, in the same manner as does probably a 
bee or ant, when it blindly follows its instincts. Under cir- 
cumstances of extreme peril, as during a fire, when a man en- 
deavors 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 afterward reflect 
over his own conduct, he would feel that there lies within him 

39 See on this subject copious evidence in tions in ourselves, I would maintain that we 

Chap. vii. of Sir J. Lubbock, *' Origin of find everywhere in consciousness extra-re- 

Civiiization," 1870. garding impulse, directed toward something 

^"^ Vox instance, Lecky, " History of Euro- that is not pleasure ; that in many cases the 

pean Morals," vol. i. p. 124. impulse is so far incompatible with the self- 

*' This teim is used in an able article in regarding that the two do not easilj" co exist 

the " Westminster Review," Oct , 1869, p. in the same moment of consciousness." A 

498. For the " Greatest happiness principle," dim feeling that our impulses do not by any 

see J. S. Mill, "," p. 17. moans always arise from any contempora- 

•** Mill recognizes (" Systi-m of Logic," neons or anticipated ple.Tsure, has, I cannot 

vol. ii. p. 422) in the clearest manner, that but think, been one chief cause of the ac- 

actions may be performed through habit ceptance of the intuitive theory of morality, 

without the anticipation of pleasure. Mr. and of the rejection of the utilitarian or 

H. Siilgwick also, in his Essay on Pleasure '* Greatest happiness " theory. With respect 

and Desire ("The Contemporary Review," to the latter theory, the standard and the 

April, 1872, p. 671), remarks : " To sum up, motive of conduct have no doubt often been 

in contravention of the doctrine that our con- confused, but they are really in some degree 

scious active impulses are always directed blended, 
toward the production of agreeable sensa* 

135 THE DESCENT OF MAN, /part t 

an impulsive power widely different from a search after pleas- 
ure or haj)piness ; 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 de- 
veloped for the general good rather than for the general hap- 
piness of the species. The term, general good, may be defined 
as the rearing of the greatest number of individuals in full vigor 
and health, with all their facidties 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 practi- 
cable, to use the same definition in both cases, and to take as 
the standard of morality the general good or welfare of the 
commxunity, rather than the general happiness ; but this defini- 
tion would perhaps require some limitation on account of polit- 
ical 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, how- 
ever, 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 re- 
moved 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 

The wishes and opinions of the members of the same com- 
munity, expressed at first orally, but later by writing also, 
either form the sole guides of our conduct or greatly reinforce 
the social instincts ; such opinions, however, have sometimes 
a tendency directly opposed to these instincts. This latter 
fact is well exemplified by the Law of Honor, that is, the law 
•f the opinion of our equals, and not of all our countrymen* 

4;hap. IV.] MORAL ShJ^E. 137 

The breach of tliis law, even when the breach is known to be 
strictly accordant with true morality, has caused many a man 
more agony than a real crime. We recognize the same influ- 
ence 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 
3ome rude experience of what is best in the long run for all the 
members ; but this judgment will not rarely err from ignorance 
and weak powers of reasoning. Hence the strangest customs 
and superstitions, in complete opposition to the true welfare 
and happiness of mankind, have become all-powerful through- 
out 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 proD- 
ably be the more severe. 

How so many absurd rules of conduct, as well as so many 
absurd religious beliefs, have originated, we do not know ; nor 
how it is that they have become, in all quarters of the world, 
so deeply impressed on the mind of men ; but it is worthy of 
remark that a belief constantly inculcated during the early 
years of life, while the brain is impressible, appears to acquire 
almost the nature of an instinct ; and the very essence of an 
instinct is that it is followed independently of reason. Neither 
can we say why certain admirable virtues, such as the love of 
truth, are much more highly appreciated by some savage tribes 
than by others ; ^^ nor, again, why similar differences prevail 
even among highly civilized nations. Knowing how firmly 
fixed many strange customs and superstitions have become, we 
need feel no surprise that the self-regarding virtues, supported 
as they are by reason, should now appear to us so natural as to 
be thought innate, although they were not valued by man in 
his early condition. 

Notwithstanding many sources of doubt, man can generally 
and readily distinguish between the higher and lower moral 
rules. The higher are founded on the social instincts, and re- 
late to the welfare of others. They are supported by the ap- 
probation of our fellow-men and by reason. The lower rules, 
though some of them when implying self-sacrifice hardly de- 

*' Good instances are given by Mr. Wal- and more fully in his " Contributions to th6 
lace in " Scientific Opinion," Sept. 15, 1869 ; Theory of Natural Selection," 1870, p. 353. 

135 TFIE DESCENT OF MAN. [past t 

serve to be called lower, relate chiefly to self, and arise froir 
public opinion, matured by experience and cultivation ; for 
they are not practised by rude tribes. 

As man advances in civilization, and small tribes are united 
into larger communities, the simplest reason would tell each 
individual that he ought to extend his social instincts and 
sympathies to all the members of the same nation, though per- 
sonally unknown to him. This point being once reached, 
there is only an artificial barrier to prevent his sympathies ex- 
tending to the men of all nations and races. If, indeed, such 
men are separated from him by great differences in appearance 
or habits, experience unfortunately shows us how long 'A is 
before we look at them as our fellow-creatures. Sympathy 
beyond the confmes of man, that is, humanity to the lowei 
animals, seems to be one of the latest moral acquisitions. It is 
apparently unfelt by savages, except toward their pets. How 
little the old Romans knew of it is shown by their abhorrent 
gladiatorial exhibitions. The very idea of humanity, as far as 
I could observe, was new to most of the Gauchos of the Pam- 
pas. This virtue, one of the noblest with which man is en- 
dowed, seems to arise incidentally from our sympathies becom- 
ing more tender and more widely diffused, until they are 
extended to all sentient beings. As soon as this virtue is 
honored 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 rec- 
ognize that we ought to control our thoughts, and " not even 
in inmost thought to think again the sins that made the past so 
pleasant to us." ^ Whatever makes any bad 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 ex- 
plained his views on^the moral sense. He says,^ '* I believe 
that the experiences of utihty, organized and consolidated 
through all past generations of the human race, have been pro- 
ducing corresponding modifications, which, by continued 
transmission and accumulation, have become in us certain far 

** Tennyson, " Idylls of the King," p. edit., 1869, p. 112. Marcus Aurelius wi, 

244. born A.D. 121. 

*^ "The Thoughts of the Emperor M. ** Letter to Mr. Mill in Bain's " Meat} 

Aurelius Antoninus," Eng. transiat« sd and Moral Science," z868, p. 722. 

CHAP, tv.i MORAr, 3E.VSS. 1 33 

ulties of moral intuition — certain emotions responding to right 
and wrong conduct, which have no apparent basis in the in- 
dividual 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 vari- 
ous dispositions and habits transmitted by many of our domes- 
tic 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 ranl'CS ; and as stealing is a rare 
crime in the wealthy classes, we can hardly account by acci- 
dental coincidence for the tendency occurring in two or three 
members of the same family. If bad tendencies are transmitted, 
it is probable that good ones are likewise transmitted. That the 
state of the body, by affecting the brain, has great influence on 
the moral tendencies, is known to most of those who have suf 
fered from chronic derangements of the digestion or liver. 
The same fact is likewise shown by the ** perversion or destruc- 
tion of the moral sense being often one of the earliest symp^ 
toms of mental derangement ; " 4? and insanity is notoriousl> 
often inherited. Except through the principle of the trans- 
mission of moral tendencies, we cannot understand the differ- 
ences 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 di- 
rectly 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, human- 
ity to animals, etc., that they become first impressed on the 
mental organization through habit, instruction, and example, 
continued during several generations in the same family, and 
in a quite subordinate degree, or not at all, by the individuals 
possessing such virtues having succeeded best in the struggle 
for life. My chief source of doubt with respect to any such 
inheritance is that senseless customs, superstitions, and tastes, 
such as the horror of a 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 prob- 
able than that animals should acquire inherited tastes for cer- 
tain kinds of food or fear of certain foes. 

«' Maudslcy, " Body and Mind," 18^, p. 6a 

i40 THE DESCENT OF MAI9 [part l 

Finally the social instincts, which no doubt were acquired 
by man as by the lower animals for the good of the commu- 
nity, will from the first have given to hiin some wish to aid liis 
fellows, some feeling of sympathy, and have compelled him to 
regard their ai)probation 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 intellect- 
ual power, and was enabled to trace the more remote conse- 
quences 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 fel- 
low-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, and other useless members of society, and 
finally to the lower animals — so would the standard of his 
morality rise higher and higher. And it is admitted by moral- 
ists 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 re- 
marked, 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 dissatis- 
faction, shame, repentance, or remorse analogous to the feelings 
caused by other powerful instincts or desires, when left unsatis- 
fied or balked. We compare the weakened impression of a 
past temptation with the ever-present social instincts, or with 
habits gained in early youth and strengthened during our 
whole lives, until they have become almost as strong as instincts. 
If with the temptation still before us we do not yield, it is 
because either the social instinct or some custom is at the 
moment predominant, or because we have learned that it will 
appear to us hereafter the stronger, when compared with the 

4« A writer in the " North British Review " *' See his remarkable work on " Heredi- 

(July, 1869, p. 531), well capable of forming tary Genius," 1869, p. 349. The Duke of 

a sound judgment, expresses himself strong- Argyll (" Primeval Man," 1869, p. 1E8) ha5 

h' in favor of this conclusion. Mr. Lecky some good remarks on the contest in man's 

C" Hist, of Morals," vol. i. p. 143) seems to nature between right and wrong. 
S certain e^ tent to coir\cide »^etein. 


weakened impression of the temptation, and we realise that its 
violation would cause us suffering. Looking to future genera- 
tions, there is no cause to fear that the social instincts will 
grow weaker, and we may expect that virtuous habits will 
grow stronger, becoming perhaps fixed by inheritance. In this 
case the struggle between our higher and lower impulses will 
be less severe, and virtue will be triumphant. 

Summary of the last Two Chapters. — There can be no doubt 
that the difference between the mind of the lowest man and 
that of the highest animal is immense. An anthropomorphous 
ape, if he could take a dispassionate view of his own case, would 
admit that, though he could form an artful plan to plunder a 
garden — though he could use stones for fighting or for break- 
ing open nuts — yet that the thought of fashioning a stone into 
a tool was quite beyond his scope. Still less, as he would ad- 
mit, could he follow out a train of metaphysical reasoning, or 
solve a mathematical problem, or reflect on God, or admire a 
grand natural scene. Some a[)es, however, would probably 
declare that they could and did admire the beauty of the col- 
ored skin and fur of their partners in marriage. They would 
admit that, though they could make other apes understand by 
cries some of their perceptions and simpler wants, the notion 
of expressing definite ideas by definite sounds had never crossed 
their minds. They might insist that they were ready to aid 
their fellow-apes of the same troop in many ways, to risk their 
lives for them, and to take charge of their orphans ; but they 
would be forced to acknowledge that disinterested love for all 
living 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, etc., of which man boasts, may be 
found in an incipient, or even sometimes in a well-developed 
condition, in the lower animals. They are also capable of 
some inherited improvement, as we see in the domestic dog 
compared with the wolf or jackal. If it could be proved that 
certain high mental powers, such as the formation of general 
concepts, self-consciousness, etc., 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 intellectual faculties ; and these a^ain mainly 

?42 THE DR^CkMT OF MAI^. \vKvci i 

the result of the continued use of a perfect language. At what 
age does the new-born infant [jossees 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 ascend- 
ing organic scale. The half-art, half-instinct of language still 
bears the stamp of its gradual evolution. The ennobling belief 
in God is not universal with man ; and the belief in spiritual 
agencies naturally follows from other mental powers. The moral 
sense perhaps affords the best and highest distinction between 
man and the lower animals ; but I need say nothing on this head, 
as I have so lately endeavored to show that the social instincts 
—the prime principle of man's moral constitution ^ — with the 
aid of active intellectual powers and the effects of habit, natu- 
rally lead to the golden rule, ** As ye would that men should do 
to you, do ye to them likewise ; " and this lies at the founda- 
tion of morality. 

In the next chapter I shall make some few remarks on the 
probable steps and means by which the several mental and 
moral faculties of man have been gradually evolved. That 
such evolution is at least possible, ought not to be denied, for 
we daily see these faculties developing in every infant ; and we 
may trace a perfect gradation from the mind of an utter idiot, 
lower than that of an animal low in the scale, to the mind of 
a. Newton. 



Advancement of the intellectual powers through natural selection — Im- 
portance of imitation — Social and moral faculties — Their development 
within tlie limits of the same tribe — Natural selection as affecting civil- 
ized nations — Evidence that civilized 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 fragmen- 
tary manner. Mr. Wallace, in an admirable paper before re- 
ferred to,^ argues that man, after he had partially acquired 
those intellectual and moral faculties which distinguish him 
^om the lower animals, would have been but little liable to 

60 '• The Thoughts of Marcus Aurelius,'"' » " Anthropoiogical Review," May, 18641 
ttc, p. 139. pk dviii. 


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 Hfe. He invents weapons, tools, and various 
stratagems to procure food and to defend himself. When he 
migrates into a colder climate he uses clothes, builds sheds, 
and makes fires ; and by the aid of fire cooks food otherwise 
indigestible. He aids his fellow-men in many ways, and an- 
ticipates future events. Even at a remote period he practised 
£ome division of labor. 

The lower animals, on the other hand, must have their bod- 
ily 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 m.oJified, they will cease to 

The case, however, is widely different, as Mr. Wallace has 
with justice insisted, in relation to the intellectual and moral 
faculties of man. These faculties are variable ; and we have 
every reason to believe that the variations tend to be inherited. 
Therefore, if they were formerly of high importance to prime- 
val 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 de- 
fend themselves, would rear the greatest number of offspring. 
The tribes which included the largest number of men thus en- 
dowed 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 absorption of other tribes.^ The stature and 

' After a time the members or tribes which 1861, p. 131), that they are the CO*d€SCfllul^ 
are absorbed into another tribe assume, as ants of the samc ancestors. 
6ir Hcn»3r Maine remarks (*• Ancient L<aw," 

144 THE DESCENT OF MAN. Jpart i; 

Strength of the men of a tribe are Hkewise of some importance 
for its success, and these depend in i)art on the nature and 
amount of the food which can be obtained. In Europe the 
men of the Bronze period were sui)i)lanted by a race more 
powerful, and, judging from their sword-handles, with larger 
hands ; ^ but their success was probably still more due to their 
superiority in the arts. 

All fcvaX. we know about savages, or may infer from their 
traditions and from old monuments, the history of which is 
quite forgotten by the present inhabitants, show that from the 
remotest times successful tribes have supplanted other tribes. 
Relics of extinct or forgotten tribes have been discovered 
throughout the civilized regions of the earth, on the wild 
plains of America, and on the isolated islands in the Pacific 
Ocean. At the present day civilized nations are everywhere 
supplanting barbarous nations, excepting where the climate 
opposes a deadly barrier ; and they succeed mainly, though 
not exclusively, through their arts, which are the products of 
the intellect. It is, therefore, highly probable that with man- 
kind the intellectual faculties have been mainly and gradually 
perfected through natural selection ; and this conclusion is 
sufficient for our purpose. Undoubtedly it would be interest- 
ing to trace the development of each separate faculty from the 
state in which it exists in the lower animals to that in which it 
exists in man ; but neither my ability nor knowledge permits 
the attempt. 

It deserves notice that, as soon as the progenitors of man be- 
came 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 
v/ay 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 ani- 
mal can be caught in the same place by the same sort of trap, 
shows that animals learn by experience, and imitate the cau- 
tion of others. Now, if some one man in a tribe, more saga- 
cious than the others, invented a new snare or weapon, or 
other means of attack or defence, the plainest self-interest, 
v>^ithout 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 
• MqHq^ " §QC» Y^ua. Sq. Nat.," i§$Q, p, 304, 


were an important one, the tribe would increase in number, 
spread, and supplant other tribes. In a tribe thus rendered 
more numerous there would always be a rather greater chance 
of the birth of other superior and inventive members. If such 
men left children to inherit their mental superiority, the chance 
of the birth of still more ingenious members would be some- 
what 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 progenitors 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 
Ivould have felt uneasy when separated from their comrades, 
for whom they would have felt some degree of love ; they 
»vould 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 dis- 
puted by no one, were no doubt acquired by the progenitors 
of man in a similar manner, namely, through natural selection, 
aided by inherited habit. When two tribes of primeval man, 
living in the same country, came into competition, if (other 
circumstances being equal) the one tribe included a great num- 
ber of courageous, sympathetic, and faithful members, who 
were always ready to warn each other of danger, to aid and 
defend each other, this tribe would succeed better and conquer 
the other. Let it be borne in mind how all-important, in the 
never-ceasing wars of savages, fidelity and courage must be. 
The advantage which disciplined soldiers have over undis- 
ciplined hordes follows chiefly from the confidence which each 
man feels in his comrades. Obedience, as Mr. Bagehot has 
well shown, ^ is of the highest value, for any form of govern- 
ment is better than none. Selfish and contentious people will 
not cohere, and without coherence nothing can be effected. A 

* T have given instances in my " Variation " Physics and Politics," in the " Fortnightly 
of Animals under Domestication," vol. ii. p. Review," Nov., 1867 ; April i, 1868 ; July I« 
196. 1869, since separately published. 

• Sec a rea)axk4blc 9?ric§ of articles on 

14^ THE DESCENT OF MAN, (part I.' 

tribe 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 through- 
out 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 
excellence raised ? It is extremely doubtful whether the off- 
spring 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 in- 
herit 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 nat- 
ural selection, that is, by the survival of the fittest \ for we 
are not here speaking of one tribe being victorious over an- 

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 
foresight of the members became improved, each man would 
soon learn that if he aided his fellow-men, he would commonly 
receive aid in return. From this low motive he might acquire 
the habit of aiding his fellows ; and the habit of performing 
benevolent actions certainly strengthens the feeling of sympathy 
which gives the first impulse to benevolent actions. Habits, 
moreover, followed during many generations, probably tend to 
be inherited. 

But another and much more powerful stimulus to the devel- 
opment 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 be- 
stow both praise and blame on others, while we love the for- 
iner and dread the latter when applied to QUfseives \ 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 develop- 
ment, became capable of feeling and being impelled by the praise 
or blame of their fellow-creatures, we cannot, of course, say. 
But it appears that even dogs appreciate encouragement, praise, 
and blame. The rudest savages feel the sentiment of glory, as 
they clearly show by preserving the trophies of their prowess, 
by their habit of excessive boasting, and even by the extreme 
care which they take of their personal appearance and decora- 
tions ; for unless they regarded the opinion of their comrades, 
such habits would be senseless. 

They certainly feel shame at the breach of some of their 
lesser rules, and apparently remorse, as shown by the case of the 
Australian who grew thin and could not rest from having de- 
layed 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 him- 
self 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, of the love of praise and the dread of blame. 
A man who was not impelled by any deep, instinctive feeling 
to sacrifice his life for the good of others, yet was roused to 
such actions by a sense of glory, would by his example excite 
the same wish for glory in other men, and would strengthen by 
exercise the noble feeling of admiration. He might thus do 
far more good to his tribe than by begetting offspring with a 
tendency to inherit his own high character. 

With increased experience and reason, man perceives the 
more remote consequences of his actions, and the self-regard ing 
virtues, such as temperance, chastity, etc., which during early 

« Mr. Wallace gives cases in his "Contributions to the Theory of Natural Selcctioo,' 
«87o, p. 354. 

148 THE DESCEJ^T OF MAN. [pAsfi 4, 

times are, as we have before seen, utterly disregarded, come to 
be highly esteemed or even held sacred. I need not, however, 
repeat what 1 have said on this head in the fourth chai>ter. 
Ultimately our moral sense or conscience becomes a highly 
complex sentiment — originating in the social instincts, largely 
guided by the approbation of our fellow-men, ruled by reason, 
self-interest, and in later times by deep religious feelings, and 
confirmed by instruction and habit. 

It must not be forgotten that although a high standard of 
morality gives but a slight or no advantage to each individual 
man and his children over the other men of the same tribe, yet 
that an increase in the number of well-endowed men and an 
advancement in the standard of morality will certainly give an 
immense advantage to one tribe over another. A tribe includ- 
ing many members who, from possessing in a high degree the 
spirit of patriotism, fidelity, obedience, courage, and sympathy, 
were always ready to aid one another, and to sacrifice them- 
selves for the common good, would be victorious over most 
other tribes ; and this would be natural selection. At all 
times throughout the world tribes have supplanted other tribes ; 
and as morality is one important element in their success, the 
standard of morality and the number of well-endowed men will 
thus everywhere tend to rise and increase. 

It is, however, very difficult to form any judgment why one 
particular tribe and not another has been successful and has 
risen in the scale of civilization. Many savages are in the same 
condition as when first discovered several centuries ago. As 
Mr. Bagehot has remarked, we are apt to look at progress as 
normal in human society ; but history refutes this. The an- 
cients did not even entertain the idea, nor do the Oriental 
nations at the present day. According to another high author- 
ity, Sir Henry Maine,^ '' the greatest part of mankind has 
never shown a particle of desire that its civil institutions 
should be improved." Progress seems to depend on many 
concurrent favorable conditions, far 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 favorable 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 

"> "Ancient Law," 1861, p. 22. For Mr. Bagehot's remarks, " Fortnightly Review," 
April X, 1868, p. 452. 


dense forests of the tropics, or along the shores of the sea, have 
in every case been highly detrimental. While 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 requi- 
sites for civilization. Such habits almost necessitate the culti- 
vation of the ground ; and the first steps in cultivation would 
probably result, as I have elsewhere shown,^ from some such 
accident as the seeds of a fruit-tree falling on a heap of refuse, 
and producing an unusually fine variety. The problem, how- 
ever, of the first advance of savages toward civilization is at 
present much too difficult to be solved. 

Natural Selection as Affecting Civilized Nations. — I have 
hitherto only considered the advancement of man from a semi- 
human condition to that of the modern savage. But some 
remarks on the action of natural selection on civilized nations 
may be worth adding. This subject has been ably discussed 
by Mr. W. R. Greg,^ and previously by Mr. 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 vigor- 
ous state of health. We civilized 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 insti- 
tute poor-laws ; and our medical men exert their utmost skill 
to save the life of everyone to the last moment. There is 
reason to believe that vaccination has preserved thousands who 
from a weak constitution would formerly have succumbed to 
small-pox. Thus the weak members of civilized societies 
propagate their kind. No one who has attended to the breed- 
ing 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 

■ " The Variation of Animals and Plants Lankester in his " Comparative Longevity," 

under Domestication," vol. i. p. 309. 1870, p. 128. Similar views appeared pre* 

' " Fraser's Magazine," Sept., 1868, p. viously in the "Australasian," July 13, 1867. 

353. This article seems to have struck I have borrowed ideas from several of these 

many persons, and has given rise to two writers. 

remarkable essays and a rejoinder in the i** Kor Mr. Wallace, see *' Anthropolo^:. 

" Spectator," Oct. 3d and 17th, 1868. It Review," as before cited. Mr. Gallon in 

has also been discussed in the "Q. Journal " Macmilian's Magazine," Aug., 1865, p. 

of Science," 1869, p. 152, and by Mr. Law- 318 ; also his great work, "Hereditary 

son Tait in the " Dublin Q. Journal of Medi- Genius," i8jo. 
cal Science," Feb., 1869, and by Mr. £. Ray 

: i, : THE descent of man. ipa£t ^ 

The aid which we feel impelled to give to the helpless is 
mainly an incidental result of the instinct of sympathy, which 
was originally acquired as part of the social instincts, but sub- 
sequently rendered, in the manner previously indicated, more 
tender and more widely diffused. Nor could we check our 
sympathy, even at the urging of hard reason, without deterio- 
ration in the noblest part of our nature. Thie surgeon may 
harden himself while performing an operation, for he knows that 
he is acting for the good of his patient ; but if we were inten- 
tionally to neglect the weak and helpless, it could only be for 
a contingent benefit, with an overwhelming present evil. We 
must therefore bear the undoubtedly bad effects of the weak 
surviving and propagating their kind ; but there appears to be 
at least one check in steady action, namely, that the weaker and 
inferior members of society do not marry so freely as the sound ; 
and this check might be indefinitely increased by the weak in 
body or mind refraining from marriage, though this is more to 
be hoped for than expected. 

In every country in which a large standing army is kept up, 
the finest young men are taken by the conscription or are 
enlisted. They are thus exposed to early death during war, are 
often tempted into vice, and are prevented from marrying dur- 
ing the prime of life. On the other hand, the shorter and 
feebler men, with poor constitutions, are left at home, and 
consequently have a much better chance of marrying and 
propagating their kind.^^ 

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 vigor, come into their property sooner than other children, 
and will be likely to marry earlier, and leave a larger number of 
offspring to inherit their inferior constitutions. But the inheri- 
tance of property by itself is very far from an evil ; for without 
the accumulation of capital the arts could not progress ; and it 
is chiefly through their power that the civilized races have 
extended, and are now everywhere extending their range, so as 
to take the place of the lower races. Nor does the moderate 
accumulation of wealth interfere with the process of selection. 
When a poor man becomes moderately rich, his children enter 

*1 Prof. H. Fick ("Einfluss der Natur- has some good remarks on this head, and oa 
wissenschaft auf das Rccht," June, iS-jz) other such points. 


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 labor for their 
daily bread, is important to a degree which cannot be over- 
estimated ; as all high intellectual work is carried on by them, 
and on such work material progress of all kinds mainly de- 
pends, not to mention other and higher advantages. No doubt 
v/ealth when very great tends to convert men into useless 
drones, but their number is never large ; and some degree of 
elimination here occurs, for we daily see rich men, who hap- 
pen 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, while the younger sons, however superior in 
these respects, do not so generally marry. Nor can worthless 
eldest sons with entailed estates squander their wealth. But 
here, as elsewhere, the relations of civilized hfe are so complex 
that some compensatory checks intervene. The men who are 
rich through primogeniture are able to select generation after 
generation the more beautiful and charming women ; and these 
must generally be healthy in body and active in mind. The 
evil consequences, such as they may be, of the continued 
preservation of the same line of descent, without any selection, 
are checked by men of rank always wishing to increase their 
wealth and power ; and this they effect by marrying heiresses. 
But the daughters of parents who have produced single children 
are themselves, as Mr. Galton ^^ has shown, apt to be sterile ; 
and thus noble families are continually cut off in the direct 
line, and their wealth flows into some side channel ; but, 
imfortunately, this channel is not determined by superiority 
of any kind. 

Although civilization thus checks in many ways the action of 
natural selection, it apparently favors the better development 
of the body, by means of good food and the freedom from 
occasional hardships. This may be inferred from civilized 
men having been found, wherever compared, to be physically 
stronger than savages. ^^ They appear also to have equal powers 
of endurance, as has been proved in many adventurous expedi- 
tions. Even the great luxury of the rich can be but little det- 

» •* Hereditary Genius.-" 1870, pp. 132- '"' Quatrefages, "Revue des Cours Sci«Bf. 
'40- rifiques," 1867-68, p. 659. 

152 THE DESCENT OF MA^T, [part L 

rimental, 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.^' 

Wc will now look to the intellectual faculties. If in each 
grade of society them embers were divided into two equal bod- 
ies, 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 labor, a very small one. Hence 
in civilized nations the^e 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 multi- 
plication 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, shown that men of eminence are by no means 
so." Great lawgivers, the founders of beneficent religions, 
great philosophers and discoverers in science, aid the progress 
of mankind in a far higher degree by their works than by leav- 
ing a numerous progeny. In the case of corporeal structures 
it is the selection of the slightly better-endowed and the 
elimination of the slightly less well-endowed individuals, and 
not the preservation of strongly marked and rare anomalies, 
that leads to the advancement of a species. ^^ So it will be with 
the intellectual faculties, since the somewhat abler men in each 
grade of society 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 intellectual men have increased, we may expect, from the law 
of the deviation from an average, that prodigies of genius will, 
as shown by Mr. Galton, appear somewhat more frequently than 

In regard to the moral qualities, some elimination of the 

'* See the fifth and sixth columns, com- '* " Hereditary Genius." 1S70, p. 330. 

piled from good authorities, in the table iR " Origin of Species" fifth edirion,i869i 

given in Mr. E. R. I.ankester's " Compara- p. 104. 
tive Longevity," 1870, p. 115, 


worst dispositions is always in progress,even in the most civilized 
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 civilization ^"^ — emigrate 
to newly settled countries, where they prove useful pioneers. 
Intemperance is so highly destructive, that the expectation of 
life of the intemperate, at the age of thirty for instance, is only 
13.8 years; while for the rural laborers of England at the 
same age it is 40.59 years. ^^ Profligate women bear few 
children, and profligate men rarely marry ; both suffer from 
disease. In the 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 ele- 
ment toward 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 dis- 
positions, which occasionally without any assignable cause 
make their appearance in families, may perhaps be reversions to 
a savage state, from which we are not removed by very many 
generations. This view seems indeed recognized in the com- 
mon expression that such men are the black sheep of the 

With civiHzed nations, as far as an advanced standard of 
morality and an increased number of fairly good men are con- 
cerned, natural selection apparently effects but little ; though 
the fundamental social instincts were originally thus gained. 
But I have already said enough, while treating of the lower 
races, on the causes which lead to the advance of morality, 
namely, the approbation of our fellow-men — the strengthening 
of our sympathies by habit — example and imitation — reason — • 
experience, and even self-interest — instruction during youth, 
and religious feelings. 

A most important obstacle in civilized countries to an 
Increase in the number of men of a superior class has been 
strongly insisted on by Mr. Greg and Mr. Galton,^^ namely, 

^ " Hereditary Genius," 1870, p. 347. " Nat. Assoc, for the Promotion of Social 

'8 E. Ray Lankester, "Comparative Science," 1858. 

Longevity," 1870, p. 115. The table of the '"'• Fraser's Magazine." Sept. 1868, p. 353. 

intemperate is from Neison's "Vital Statis- " Macmillan's Magazine," Aug. 1865, p. 318. 

tics." In regard to profligacy, see Dr. Farr, The Rev. F. VV. Farrar ("Fraser's Mag.," 

••Influence of Marriage on Mortality," Aug., 1870, p. 264) takes a diflferent view. 

154 ^^^^ DESCENT OF MAN. [part u 

the fact that the very poor and reckless, who are often degraded 
by vice, almost invariably marry early, while the careful and 
frugal, who are generally otherwise virtuous, marry late in life, 
so that they may be able to support themselves and their 
children in comfort. Those who marry early produce within 
a given period not only a greater number of generations, but, 
as shown by Dr. Duncan,'-"^ they produce many more children. 
The children, moreover, that are born by mothers during the 
prime of life are heavier and larger, and therefore probably 
more vigorous, than those born at other periods. Thus the 
reckless, degraded, and often vicious members of society tend 
to increase at a quicker rate than the provident and generally 
virtuous members. Or as Mr. Greg puts the case : *' The care- 
less, squalid, unaspiring Irishman multiplies like rabbits : the 
frugal, foreseeing, self-respecting, ambitious Scot, stern in his 
morality, spiritual in his faith, sagacious and disciplined in hi? 
intelligence, passes his best years in struggle and in celibacy, 
marries late, and leaves few behind him. Given a land origi- 
nally 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 in- 
tellect, would belong to the one-sixth of Saxons that remained. 
In the eternal 'struggle for existence,' it would be the inferior 
and less favored race that had prevailed — and prevailed by 
virtue not of its good quahties, but of its faults." 

There are, however, some checks to this downward tendency. 
We have seen that the intemperate suffer frorn a high rate of 
mortality, and the extremely profligate leave few offspring. 
The poorest classes crowd into towns, and it has been proved 
by Dr. Stark, from the statistics of ten years in Scotland, ^^ that 
at all ages the death-rate is higher in towns than in rural dis- 
tricts, " and during the first five years of life the town death- 
rate is almost exactly double that of the rural districts. ' ' As 
these returns include both the rich and the poor, no doubt 
more than twice the number of births would be requisite to 
keep up the number of the very poor inhabitants in the towns, 
relatively to those in the country. With women, marriage at 
too early an age is highly injurious ; for it has been found in 
France that, *' twice as many wives under twenty die in the 

'0 " On the Laws of the Fertility of Mr. Gahon, " Hereditary Genius," pp. 352- 

Women," in "Transact. Royal Soc." Edin- 357, for observations to the above effect, 

burgii, vol. xxiv. p. 287; now ptiblisbed ^i "Tenth Annual Report of Birlh& 

separately under the title of "Fecundity, Deaths, etc., in Scotland." vS'^?, p. ?cxLx. 
Fertility, and Steriiity," 18^1. See, ^Isb, 

CHAP, v.] Civilized RATIONS. 155 

year, as died out of the same number of the unmarried.'* The 
ir.ortahty, 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 famihes in comfort were to select, as they often 
do, women in the prime of life, the rate of increase in the 
better class would be only slightly lessened. 

It was established from an enormous body of statistics, taken 
during 1853, that the unmarried men throughout France, be- 
tween the ages of twenty and eighty, die in a much larger 
proportion than the married ; for instance, out of every 1,000 
unmarried men, between the ages of twenty and thirty, 11.3 
annually died, while of the married only 6.5 died.^ Asimilar 
law was proved to hold good, during the years 1863 and 1864, 
with the entire population above the age of twenty in Scotland ; 
for instance, out of every 1,000 unmarried men, between the ages 
of twenty and thirty, 14.97 annually died, while of the married 
only 7.24 died, that is less than half ^^ Dr. Stark remarks on 
this, " Bachelorhood is more destructive to life than the most 
unwholesome trades, or than residence in an unwholesome 
house or district where there has never been the most 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 consti- 
tution, ill-health, or any great infirmity in body or mind, will 
often not wish to marry, or will be rejected. Dr. Stark seems 
to have come to the conclusion that marriage in itself is a main 
cause of prolonged life, from finding that aged married men 
still have a considerable advantage in this respect over the 
unmarried of the same advanced age ; but everyone must have 
known instances of men who, with weak health during youth, 
did not marry, and yet have survived to old age, though re- 
maining weak, and therefore always with a lessened chance 
of life or of marrying. There is another remarkable circum- 
stance which seems tr support Dr. Stark's conclusion, namely, 

" These quotations nre taken from our '^* I have taken the mean of the quinquen- 

highest authority on such questions, name- nial means, given in "The Tenth Annual 

ly, Dr. Farr, in his paper "On the Influ- Report of Births, Deaths, etc.. in Scotland," 

ence of Marriage on the Mortality of the 1867. The quotation from Dr. Stark is 

French People," read before the Nat. Assoc, copied from an article m the " Daily News," 

for the Promotion of Social Science 1858. October 17. 1868, which Dr. Fanr considers 

'^ Dr. Farr, ih. The quotations given helow ve'" ''"•^fuUy writtca* 
&re extracted from the same striking paper. 

156 THE DESCENT OF MAN. Ipaht t 

that widows and widowers in France suffer in comi)arison with 
the married a very heavy rate of mortality ; but Dr. l*'arr 
attributes this to the poverty and evil habits consequent on the 
disruption of the family, and to grief. On the whole, we may 
conclude with Dr. Farr that the lesser mortality of married 
than of unmarried men, which seems to be a general law, " is 
mainly due to the constant elimination of imperfect types, and 
to the skilful selection of the finest individuals out of each suc- 
cessive generation ; " the selection relating only to the mar- 
riage 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 suf- 
fer 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 
increasing at a quicker rate than the better class of men, the 
nation will retrograde, as has too often occurred in the history 
of the world. We must remsmber that progress is no invariable 
rule. It is very difficult to say why one civilized nation rises, 
becomes more powerful, and spreads more widely, than another ; 
or why the same nation progresses more quickly at one time 
than at another. We can only say that it depends on an in- 
crease 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 vigor of body 
leads to vigor of mind. 

It has been urged by several writers that as high intellectual 
powers are advantageous to a nation, the old Greeks, who stood 
some grades higher in intellect than any race that has ever 
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 toward continued development in 
mind and body. But development of all kinds depends on 
many concurrent favorable circumstances. Natural selection 
acts only tentatively. Individuals and races may have acquired 

'* Dr. Duncan remarks ("Fecundity, leaving the unmarried columns crowded with 

Fertility," etc., 1871, page 334) on this sub- the sickly and unfortunate." 

ject : ^® See the ingenious and original argu- 

•'Atevery age the healthy and beautiful go ment on this subject by Mr. Galtoa, "He* 

•ver from die unmarried side to the married, reditary Genius," pp. 340-34* 


certain indisputable advantages, and yet have perished from 
failing in other characters. The Greeks may have retrograded 
from a want of coherence between the many small states, from 
the small size of their whole country, from the practice of 
slavery, or from extreme sensuality ; for they did not succumb 
until *' they were enervated and corrupt to the very core. "^ 
The western nations of Europe, who now so immeasurably 
surpass their former savage progenitors, and stand at the sum- 
mit of civilization, 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 se- 
lected 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. 

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 well illustrated by 
comparing the progress of the Canadians of English and French 
extraction ; but who can say how the English gained their en- 
ergy? There is apparently much truth in the belief that the 
wonderful progress of the United States, as well as the character 
of the people, are the results of natural selection ; for the more 
energetic, restless, and courageous men from all parts of Europe 
have emigrated during the last ten or twelve generations to that 

'' Mr. Greg, " Fraser's Magazine," Sep- already ("Principles of Geology,'^ vol. ii., 

tember, 1868, p. 357. 1868, p. 489) in a striking passage called 

58 "Hereditary Genius," 1870, pp. 357- attention to the evil influence of the Holy 

359. The Rev. F. W. Farrar, ("Fraser's Inquisition in having, through selection, 

Mag.," Aug., 1870, p. 257) Jidvances argu- lowered the general standard of intelligence 

menu on the other side. Sir C. Lyell had in Europe. 

1 58 THE DESCRMT OF MAIST. ^part i. 

great country, and have there succeeded best.^ Looking to the 
distant future, I do not think that the Rev. Mr. Zincke takes 
an exaggerated view when he says : =** ''All other series of 
events — as that which resulted in the culture of mind in Greece, 
and that which resulted in the empire of Rome — only apjjear 
to have purpose and value when viewed in connection with, or 
rather as subsidiary to . . . the great stream of Anglo- 
Saxon emigration to the west." Obscure as is the problem of 
the advance of civilization, we can at least see that a nation 
which produced during a lengthened period the greatest num- 
ber of highly intellectual, energetic, brave, patriotic, and benev- 
olent men, would generally prevail over less favored nations. 

Natural selection follows from the struggle for existence ; and 
this from a rapid rate of increase. It is impossible not to regret 
bitterly, but whether wisely is another question, the rate at 
which man tends to increase ; for this leads in barbarous tribes 
to infanticide and many other evils, and in civilized nations to 
iibject poverty, celibacy, and to the late marriages of the prudent. 
But as man suffers from the same physical evils as the lower 
animals, he has no right to expect an immunity from the evils 
consequent on the struggle for existence. Had he not been sub- 
jected during primeval times to natural selection, assuredly he 
would never have attained to his present rank. Since we see in 
many parts of the world enormous areas of the most fertile land 
capable of supporting numerous happy homes, but peopled only 
by a few wandering savages, it might be argued that the struggle 
for existence had not been sufficiently severe to force man up- 
ward 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 
demands many favorable concurrent circumstances ; but it may 
well be doubted whether the most favorable would have sufficed, 
had not the rate of increase been rapid, and the consequent 
struggle for existence extremely severe. It even appears from 
what we see, for instance, in parts of South America, that a 
people which may be called civilized, such as the Spanish set- 
tlers, is liable to become indolent and to retrograde, when the 
conditions of life are very easy. With highly civilized nations 
continued progress depends in a subordinate degree on natural 

2* Mr. GaIton,"Macmtllan'sMas:.,"Aug., *° "Last Winter in the United States," 
1865,9.325. See, also, "Nature," "OnDar- 1R68, p. 29. 
winism and National Life,'' Dec. 1869,9. 18*. 


selection ; for such nations do not supplant and exterminate one 
another as do savage tribes. Nevertheless, the more intelligent 
members within the same community will succeed better in the 
long run than the inferior, and leave a more numerous progeny, 
and this is a form of natural selection. The more efficient 
causes of progress seem to consist of a good education during 
youth while the brain is impressible, and of a high standard of 
excellence, inculcated by the ablest and best men, embodied in 
the laws, customs, and traditions of the nation, and 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 
appreciation 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 Civilized Nations were once Bar- 
barous. — ^The present subject has been treated in so full and 
admirable a manner by Sir J. Lubbock,^^ Mr. Tylor, Mr. 
M'Lennan, and others that I need here give only the briefest 
summary of their results. The arguments recently advanced 
by the Duke of Argyll,^ and formerly by Archbishop Whately, 
in favor of the belief that man came into the world as a civil- 
ized being, and that all savages have since undergone degra- 
dation, seein to me weak in comparison with those advanced 
on the other side. Many nations, no doubt, have fallen away 
in civilization, and some may have lapsed into utter bar- 
barism, 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 that they have fallen much below 
the Botocudos, who inhabit the finest parts of Brazil. 

The evidence that all civilized nations are the descendants 
of barbarians, consists, on the one side, of clear traces of their 
former low condition in still-existing customs, beliefs, lan- 
guage, etc.; and on the other side, of proofs that savages are 
independently able to raise themselves a few steps in the scale 
of civilization, and have actually thus risen. The evidence on 
the first head is extremely curious, but cannot be here given : 
I refer to such cases as that of the art of enumeration, which, 

'» I am much indebted to Mr. John Mor- " " On the Origin of Civilization," "Proc, 

ley for some good criticisms on this subject : of the Ethnological Society," November 26^ 

see, also, Broca, " Les Selections," '* Revue 1867. 

d'Anthropologie," 1872. '* "Primeval Man," 1869. 

l6o THE DESCENT OF MAM. [part l 

as Mr. Tylor clearly shows by reference to the words still used 
in some places, originated in counting the fingers, first of one 
hand and then of the other, and lastly of the toes. We have 
traces of this in our own decimal system, and in the Roman 
numerals, where, after the V., which is supposed to be an ab- 
breviated picture of a human hand, we pass on to VI., etc., 
when the other hand no doubt was used. So again, '' when 
we speak of threescore and ten, we are counting by the vigesi- 
mal system, each score thus ideally made standing for 20 — for 
*one man ' as a Mexican or C'arib would put it." ^' 

According to a large and increasing school of philologists, 
every language bears the marks of its slow and gradual evolu- 
tion. So it is with the art of writing, for letters are rudiments 
of pictorial representations. It is hardly possible to read Mr. 
M'Lennan's work ^' and not admit that almost all civilized 
nations still retain traces of such rude habits as the forcible 
capture of wives. What ancient nation, as the same author 
asks, can be named that was originally monogamous? The 
primitive idea of justice, as shown by the law of battle and 
other customs of which vestiges still remain, was likewise most 
rude. Many existing superstitions are the remnants of former 
false religious beliefs. The highest form of religion- -the grand 
idea of God hating sin and loving righteousness — ^wfs unknown 
during primeval times. 

Turning to the other kind of evidence : Sir J. Lubbock has 
shown that some savages have recently improved a little in 
some of their simpler arts. From the extremely curious ac- 
count which he gives of the weapons, tools, and arts in use 
among savages in various parts of the world, it cannot be 
doubted that these have nearly all been independent discover- 
ies, excepting perhaps the art of making fire.^ The Australian 
boomerang is a good instance of one such independent discov- 
ery. The Tahitians when first visited had advanced in many 
respects beyond the inhabitants of most of the other Polyne- 
sian islands. There are no just grounds for the belief that the 
high culture of the native Peruvians and Mexicans was de- 

3* "Royal Institution of Great Britain," vii.. February, 1868. Prof. Schaaffhausen 

March 15, 1867. Also, " Researches into (•• Anthropolog. Review," October, 1869, p. 

the Early History of Mankind," 1865, 373) remarks on "the vestiges of human 

3* " Primitive Marriage," 1865. See, sacrifices found both in Homer and the Old 

likewise, an excellent article, evidently by Testament." 

the same author, in the " North British Re- ^« Sir J. Lubbock, "Prehistoric Times." 

view," July, 1869. Also. Mr. L. H. Morgan, 2d edit. 1869, chap. xv. and xvi. et passim. 

"A Conjectural Solution of the Origin of See, also, the excellent ninth chapter in Ty* 

the Class System of Relationship," in lor's " Early History of Mankind," 2d edit., 

"Proc American Acad, of Sciences," vol. 1870. 

CHAP, vi.l AFfimriES AND GENEALOGY, l6l 

rived 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 mission- 
aries, a wandering crew from some semi-civilized land, if 
washed to the shores of America, would not have produced 
any marked effect on the natives, unless they had already be- 
come 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 Europe, as far east as Greece, 
in Palestine, India, Japan, New Zealand, and Africa, including 
Egypt, flint tools have been discovered in abundance ; and of 
their use the existing inhabitants retain no tradition. There 
is also indirect evidence of their former use by the Chinese 
and ancient Jews. Hence there can hardly be a doubt that 
the inhabitants of these countries, which include nearly the 
whole civilized world, were once in a barbarous condition. 
To believe that man was aboriginally civilized and then suf- 
fered utter degradation in so many regions, is to take a pitia- 
bly 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 stand- 
ard as yet attained by him in knowledge, morals, and religion. 



Position of man in the animal series — The natural system genealogical- 
Adaptive characters of slight value — Various small points of resem- 
blance between man and the Quadrumana — Rank of man in the natu- 
ral system — Birthplace and antiquity of man — Absence of fossil con- 
necting-links — Lower stages in the genealogy of man, as inferred, 
firstly from his affinities, and secondly from his structure — Early an- 
drogynous condition of the Vertcbrala — Conclusion. 

Even if it be granted that the difference between man and his 
nearest allies is as great in corporeal structure as some natural- 
ists maintain, and although we must grant that the difference 

^"^ Dr. F. MUlIcr has made some good Novara : Anthropolog. Theii," Abthcil. iii. 
remarks to this effect in the " Reise der i868, s. 127. 


between them is immense in mental power, yet the facts given 
in the earlier chapters appear to declare, in the plainest man- 
ner, that man is descended from some lower form, notwith- 
standing that connecting-links have not hitherto been discov- 

Man is liable to numerous slight and diversified variations, 
which are induced by the same general causes, are governed 
and transmitted in accordance with the same general laws, as 
in the lower animals. Man has multiplied so rapidly that he 
has ncv^^ssarily been exposed to struggle for existence, and con- 
sequently to natural selection. He has given rise to many 
races, some of which differ so much from each other that they 
have often been ranked by naturalists as distinct species. His 
body is constructed on the same homological plan as that of 
other mammals. He passes through the same phases of embry- 
ological development. He retains many rudimentary and use- 
less structures, which no doubt were once serviceable. Char- 
acters 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 ap- 
pearances, on the other hand, are intelligible, at least to a large 
extent, if man is the co-descendant with other mamn»als of 
some unknown and lower form. 

Some naturalists, from being deeply impressed with the men- 
tal and spiritual powers of man, have divided the whole organic 
world into three kingdoms — the Human, the Animal, and the 
Vegetable — thus giving to man a separate kingdom.' Spiritual 
powers cannot be compared or classed by the naturalist ; but 
he may endeavor to show, as I have done, that the mental fac- 
ulties of man and the lower animals do not differ in kind, 
although immensely in degree. A difference in degree, how- 
ever great, does not justify us in placing man in a distinct 
kingdom., as will perhaps be best illustrated by comparing the 
mental powers of two insects, namely, a coccus or scale-insect 
and an ant, which undoubtedly belong to the same class. The 
difference is here greater than, though of a somewhat different 
kind from, that between man and the highest mammal. The 
female coccus, while young, attaches itself by its proboscis to 

J Isidore Geoffroy St.-Hilaire gives a de- cations: "Hist. Nat Gen.," JQm. ii., 1859. 
tailed account of the position assigned to pp. 170-189. 
man by various naturalists in their classiE- 


a plant ; sucks the sap, but never moves again ; is fertilized 
and lays eggs ; and this is its whole history. On the other 
hand, to describe the habits and mental powers of worker- 
ants, would require, as Pierre Huber has shown, a large vol- 
ume ; 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 recog- 
nize their fellow -ants after months of absence, and feel sym- 
pathy for each other. They build great edifices, keep them 
clean, close the doors in the evening, and post sentries. They 
make roads as well as tunnels under rivers, and temporary 
bridges over them, by clinging together. They collect food 
for the community, and w^hen an object too large for entrance 
is brought to the nest, they enlarge the door, and afterward 
build it up again. They store up seeds, of which they pre- 
vent 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 emi- 
grate according 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 betv/een 
an ant and a coccus is immense ; yet no one has ever dreamed 
of placing these insects in distinct classes, much less in distinct 
kingdoms. No doubt the difference is bridged over by other 
insects ; and this is not the case with man and the higher apes. 
But we have every reason to believe that the breaks in the 
series are simply the results of many forms having become ex- 

Prof. Ov/en, 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 

l64 THE DESCENT OF MAN, [part «, 

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, color, 
or the element inhabited ; but naturalists have long felt a pro- 
found conviction that there is a natural system. This system, 
it is now generally admitted, must be, as far as possible, genea- 
logical 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 re- 
lated, so will be their descendants, and the two groups together 
will form a larger group. The amount of difference between 
the several groups — that is the amount of modification which 
each has undergone — is expressed by such terms as genera, 
families, orders, and classes. As we have no record of the 
lines of descent, the pedigree can be discovered only by ob- 
serving the degrees of resemblance between the beings which 
are to be classed. For this object numerous points of resem- 
blance are of much more importance than the amount of simi- 
larity 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 recognized 
as having sprung from a common source, notwithstanding that 
they differed greatly in some few v/ords or points of construc- 
tion. But with organic beings the points of resemblance must 
Hot consist of adaptations to similar habits of life : two animals 
may, for instance, have had their whole frames modified for 
living in the water, and yet they will not be brought any 
nearer to each 'xther in the natural system. Hence we can see 
how it is tha!i: 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 classification ; 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 great amount of modification in 
some one character ought not to lead us to separate widely any 
two organisms. A part which already differs much from the 
game part in other allied forms has already, according to the 

» Westwood, "Modem Class of Insects," vol. ii., 1840, p. 87. 


theory of evolution, varied much ; consequently it would (as 
long 0* the organism remained exposed to the same exciting 
conditions) be liable to further variations of the same kind; 
and these, if beneficial, would be preserved, and thus be con- 
tinually augmented. In many cases the continued develop- 
ment of a part, for instance, of the beak of a bird, or of the 
teeth of a mammal, would not aid the species in gaining its 
food, or for any other object ; but with man we can see no 
definite Hmit to the continued development of the brain and 
mental faculties, as far as advantage is concerned. Therefore 
in determining the position of man in the natural or genealogi- 
eal system, the extreme development of his brain ought not to 
outweigh a multitude of resemblances in other less important 
or quite unimportant points. 

The greater number of naturalists who have taken into con- 
wideration 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 Quad- 
rumana, Carnivora, etc. Recently many of our best natural- 
ists have recurred to the view first propounded by Linnceus, so 
remarkable for his sagacity, and have placed man in the same 
Order with the Quadrumana, under the title of tlie Primates. 
The justice of this conclusion will be admitted : for, in the first 
place, we must bear in mind the comparative insignificance 
for classification of the great development of the brain in man, 
and that the strongly marked differences between the skulls of 
man and the Quadrumana (lately insisted upon by Bischoff, 
Aeby, and others) apparently follow from their differently de- 
veloped brains. In the second place, we must remember that 
nearly all the other and more important differences between 
man and the Quadrumana are manifestly adaptive in their 
nature, and relate chiefly to the erect position of man ; such as 
the structure of his hand, foot, 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 char- 
acters for classification. These animals differ from all other 
Carnivora, in the form of their bodies and in the structure of 
their limbs, far more than does man from the higher apes; yet 
in most systems, from that of Cuvier to the most recent one 
by Mr. Flower,* seals are ranked as a mere family in the Order 
of the Carnivora. If man had not been his own classifier, he 

♦ " Proc. Zoolog. Soc," 1863, p, 4. 


would never have thought of founding a separate order for his 
own reception. 

It would be beyond my limits, and quite beyond my knowl- 
edge, even to name the innumerable points of structure in 
which man agrees with the other Primates. Our great anat- 
omist and philosopher. Prof. Huxley, has fully discussed this 
subject,^' and concludes that man in all parts of his organization 
differs less from the higher apes than these do from the lower 
members of the same group. Consequently there " is no justi- 
fication for placing man in a distinct order.** 

In an early part of this work I brought forward various facts, 
showing how closely man agrees in constitution with the higher 
mammals ; and this agreement must depend on our close simi- 
larity 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 relation- 
ship, 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 weep- 
ing of certain kinds of monkeys and in the laughing noise made 
by others, during which the corners of the mouth are drawn 
backward, and the lower eyelids wrinkled. The external ears 
are curiously alike. In man the nose is much more prominent 
than in most monkeys ; but we may trace the commencement 
of an aquihne curvature in the nose of the Hoolock Gibbon ; 
and this in the Semnopithecus nasica is carried to a ridiculous 

The faces of many monkeys are ornamented with beards, 
whiskers, or mustaches. The hair on the head grows to a 
great length in some species of Semnopithecus ; ^ and in the 
Bonnet monkey {Macacus radiafus) it radiates from a point 
on the crown, with a parting down the middle. It is com- 
monly said that the forehead gives to man his noble and intel- 
lectual appearance ;. but the thick hair on the head of the Bon- 

* "Evidence as to Man's Place in Nalure," * Isid. Geoffroy, " Hist. Nat. G6n.» "toflfc 
x9^3i P« 70 etptusim. ia<% i859« P* 217* 


net monkey terminates downward abruptly, and is succeeded 
by hair so short and fine that at a httle distance the forehead, 
with the exception of the eyebrows, a])pears quite naked. It 
has been erroneously asserted that eyebrows are not present in 
any monkey. In the species just named the degree of naked- 
ness of the fo~?head differs in different individuals; and Esch- 
richt 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 pro- 
genitor in whom the forehead had not as yet become quite 

It is well known that the hair on our arms tends to converge 
from above and below to a point at the elbow. This curious 
arrangement, so unlike that in most of the lower mammals, i? 
common to the gorilla, chimpanzee, orang, some species of 
Hylobates, and even to some few American monkeys. But in 
Hyiobates agilis the hair on the forearm is directly downward 
or toward the wrist in the ordinary manner ; and in II. /ar 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 
tke convergence of the hair toward the elbow on the arms of 
the orang may be explained as serving to throw off the rain, 
for this animal during rainy weather sits with its arms bent, and 
with the hands clasped round a branch or over its head. Ac- 
cording 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 direction of the hair on our own 
arms offers a curious record of our former state ; for no one 
supposes that it is now of any use in throwing off the rain ; 
nor, in our present erect condition, is it properly directed for 
this purpose. 

It would, however, be rash to trust too much to the principle 
of adaptation in regard to the direction of the hair in man or 
his early progenitors ; for it is impossible to study the figures 
given by Eschricht of the arrangement of the hair on the hu- 

' " Ueber die Richtung der Haare," etc. ' Quoted by Reade, "The African Sketch 
Miiller's " Archiv fiir Anat. undPhys.," 1837, Book," vol. i., 1873, p. 153. 


man 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 during development. There appears also to exist 
some relation between the arrangement of the hair on the 
liml)s 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, etc. — are 
all necessarily the result of unbroken inheritance from a com- 
mon progenitor, or of subsequent reversion. Many of these 
resemblances are more probably due to analogous variation, 
which follows, as I have elsewhere attempted to show,^*^ from 
co-descended organisms having a similar constitution, and hav- 
ing been acted on by like causes inducing similar modifications. 
With respect to the similar direction of the hair on the forearms 
of man and certain monkeys, as this character is common to 
almost all the anthropomorphous apes, it may probably be 
attributed to inheritance ; but this is not certain, as some very 
distinct American monkeys are thus characterized. 

Although, as we have now seen, man has no just right to 
form a separate Order for his own reception, he may perhaps 
claim a distinct Sub-order or Family. Prof. Huxley, in his 
last work," divides the Primates into three Sub-orders ; namely, 
the Anthropidae 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 v/e 
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 pro- 
ceeding from a common stock, it is quite conceivable that two 
of them might after the lapse of ages be so slightly changed as 
still to remain as species of the same genus, while the third 
line might become so greatly modified as to deserve to rank as 

' On the hair in Hylobates, see "Nat. "Contributions to the Theory of Natural 

History of Mammals," by C L. Martin, Selection," 1870, p. 344. 

1841, p. 415. Also, Isid. Geoffroy on the 1° " Origin of Species," 5th edit, 1869, p. 

American monkeys and other kinds, "Hist. 194. "The Variation of Animals and Plants 

Nat. Gen.," vol. li , 1859, pp. 216, 243. Esch- under Domestication," vol. ii.. 186S, p. 348. 

richt, ibid., s, 46, 55, 61. Owen, " Anat. of -' "An Introduction to the Classification 

Vertebrates," vol. iii. p. 619. Wallace, of Animals," 1869, p. 9f . 


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 
cla-ssifications to strongly marked differences in some few points 
— that is, to the amount of modification undergone ; and liow 
much to close resemblance in numerous unimportant point^i, 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 Simiadoe. This 
family is divided by almost all naturalists into the Catarrhine 
group, or Old World monkeys, all of which are characterized 
(as their name expresses) by the pecuhar structure of their 
nostrils, and by having four premolars in each jaw ; and into 
the Platyrhine group or New World monkeys (including two 
very distinct sub-groups), all of which are characterized by 
differently constructed nostrils, and by having six premolars in 
each jaw. Some other small differences might be mentioned. 
Now man unquestionably belongs in his dentition, in the 
structure of his nostrils, and some other respects, to the Catar- 
rhine or Old World division ; nor does he resemble the Platy- 
rhines more closely than the Catarrhines in any characters, ex- 
cepting 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 pro- 
duced 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 Catarrhine division. ^2 

The anthropomorphous apes, namely, the gorilla, chimpanzee, 
orang, and hylobates, are by most naturalists separated from 
the other Old World monkeys, as a distinct sub-group. I am 

^' This is nearly the same classification which answer to the Catarrhines, the Cebidse, 

as that provisionally adopted by Mr. St. and the Hapalida; — these two latter group* 

George Mivart ("Transact. Philosoph. answering to the Platyrhines. Mr. Mivart 

Soc," 1867, p. 300), who, after separating still abides by the same view ; see " Nat- 

the I^emundae, divides the remainder of the ure," 1871, p. 481. 
Primates into the Hominids, the Simiadae 

. (H)— VoL 3 

I70 TTTE DESCEI^r OF MAPT. (part r. 

aware that Gratiolet, relying on the structure of the brain, does 
not admit the existence of this sub-group, and no doubt it is a 
broken one. Thus the orang, as Mr. St. G. Mivart remarks,'^ 
*' is one of the most pecuhar 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 peculiar sacculated stomach, being the type of one such sub- 
group. But it appears, from M. Gaudry's wonderful discover- 
ies in Attica, that during the Miocene period a form existed 
there which connected Semnopithecus and Macacus ; and this 
probably illustrates the manner in which the other and higher 
groups were once blended together. 

If the anthropomorphous apes be admitted to form a natural 
sub-group, then as man agrees with them, not only in all those 
characters which he possesses in common with the whole Cat- 
arrhine group, but in other peculiar characters, such as the ab- 
sence 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 lav/ of analogous variation, a member of one of the other 
lower sub-groups should have given rise to a man-like creature, 
resembling the higher anthropomorphous apes in so many re- 
spects. 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 Simiadae, namely, 
the Catarrhine 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 di- 
verged to any considerable extent from each other, would still 
have formed a single natural group ; but some of the species or 
incipient genera would have already begun to indicate by their 
diverging characters the future distinctive marks of the Cat- 
arrhine and Platyrhine divisions. Hence the members of this 
supposed ancient group would not have been so uniform in 
their dentition, or in the structure of their nostrils, as are the 
existing Catarrhine monkeys in one way and the Platyrhines in 

»' "Transact. Zoolog. Soc.," vol. vi., i< Mr. St G. Mivart, "Transact Phil 
kS67, p. 214. Soc" 1867, p. 410. 


another way, but would have resembled in this respect the 
allied Lemuridse, which differ greatly from each other in the 
form of their muzzles/^ and to an extraordinary degree in their 

The Catarrhine and Platyrhine monkeys agree in a multitude 
of characters, as is shown by their unquestionably belonging 
to one and the same Order. The many characters which they 
possess in common can hardly have been independently ac- 
quired by so many distinct species ; so that these characters 
must have been inherited. But a naturalist would undoubt- 
edly have ranked as an ape or a monkey, an ancient form which 
possessed many characters common to the Catarrhine and Platy- 
rhine monkeys, other characters in an intermediate condition, 
and some few, perhaps, distinct from those now found in either 
group. And as man from a genealogical point of view belongs 
to the Catarrhine or Old World stock, we must conclude, how- 
ever 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 pro- 
genitor of the whole Simian stock, including man, was identi- 
cal with, or even closely resembled, any existing ape or mon- 

On the Birthplace and Aiitiquity of Man. — We are naturally 
led to inquire, where was the birthplace of man at that stage 
of descent when our progenitors diverged from the Catarrhine 
stock ? The fact that they belonged to this stock clearly shows 
that they inhabited the Old World ; but not Australia nor any 
oceanic island, as we may infer from the laws of geographical 
distribution. In each great region of the world the living 
mammals are closely related to the extinct species of the same 
region. It is therefore probable that Africa was formerly in- 
habited by extinct apes closely allied to the gorilla and chim- 
panzee ; and as these two species are now man's nearest allies, 
it is somewhat more probable that our early progenitors lived 
on the African continent than elsewhere. But it is useless to 
speculate on this subject ; for two or three anthropomorphous 
apes, one the Dryopithecus ^^ of Lartet, nearly as large as a 
man, and closely allied to Hylobates, existed in Europe during 

" Messrs. Murie and Mivart on the Lem- 1868, s. 61. Also his " Natiirliche Schop- 

uroidea, "Transact. Zoolog. Soc," vol. vii., fungsgeschichte," 1868, in which he gives m 

1869, p. 5. detail his views on the genealogy of man. 

'• Hackel has come to this same con- '^ Dr. C. Forsyth Major, " Sur les Sin- 
elusion. See " Ueber die Entstehung ges Fossiles trouvfes en Italie ; " ** Soc luL 
des Menschengeschlechts," in Virchow's des Sc. Nat.," torn. Jcv., 1872. 
** Sammlung. gemein* wissea. YortragCt" 

173 THE DESCENT OF MAN, [part i 

the Miocene age ; and since so remote a period the earth liaa 
certainly undergone many great revohitions, and there has 
been ample time for migration on the largest scale. 

At the period and place, whenever and wherever it was, 
when man first lost his hairy covering, he probably inha])ited 
a hot country — a circumstance favorable for the frugiferous 
diet on which, judging from analogy, he subsisted. We are 
far from knowing how long ago it was when man first diverged 
from the Catarrhine stock ; but it may have 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 Mio- 
cene period is shown by the existence of the Dryopithecus. 
We are also quite ignorant at how rapid a rate organisms, 
whether high or low in the scale, may be modified under favor- 
able circumstances ; we know, however, that some have re- 
tained 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 com- 
parison with the higher apes. 

The great break in the organic chain between man and his 
nearest allies, which cannot be bridged over by any extinct or 
living species, has often been advanced as a grave objection to 
the belief that man is descended from some lower form ; but 
this objection will not appear of much weight to those who, 
from general reasons, believe in the general principle of evolu- 
tion. Breaks often occur in all parts of the series, some being 
wide, sharp, and defined, others less so in various degrees ; as 
between the orang and its nearest allies — between the Tarsius 
and the other Lemuridse — between the elephant, and in a more 
striking manner between the Ornithorhynchus or Echidna, and 
all other mammals. But these breaks depend merely on the 
number of related forms which have become extinct. At some 
future period, not very distant as measured by centuries, the 
civilized races of man will almost certainly exterminate, and 
replace, the savage races throughout the world. At the same 
time the anthropomorphous apes, as Prof. Scha'affhausen has 
remarked, ^^ will no doubt be exterminated. The break between 
man and his nearest allies will then be wider, for it will inter- 
vene between man in a more civilized state, as we may hope, 

•• "AndiTopological Review," April, 1867, p. 236. 


even than the Caucasian, and some ape as low as a baboon, 
instead of, as now, between the negro or Austrahan and the 

With respect to the absence of fossil remains, serving to 
connect man with his ape-like progenitors, no one will lay 
much stress on this fact who reads Sir C. Lyell's discussion, ^^ 
where he shows that in all the vertebrate classes the discovery 
of fossil remains has been a very slow and fortuitous process. 
Nor should it be forgotten that those regions which are the 
most likely to afford remains connecting man with some ex- 
tinct ape-Hke creature have not as yet been searched by geol- 

Lower Stages in the Genealogy of Man. — We have seen that 
man appears to have diverged from the Catarrhine or Old World 
division of the Simiadae, after these had diverged from the New 
World division. We will now endeavor to follow the remote 
traces of his genealogy, trusting principally to the mutual affin- 
ities between the various classes and orders, with some slight 
reference to the periods, as far as ascertained, of their succes- 
sive appearance on the earth. The Lemuridae stand below and 
near to the Simiadce, 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 extraor- 
dinary degree, and includes many aberrant forms. It has, 
therefore, probably suffered much extinction. Most of the 
remnants survive on islands, such as Madagascar and the Ma- 
layan 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 vari- 
ous considerations it is probable that the Simiadae were origi- 
nally developed from the progenitors of the existing Lemuridae ; 
and these in their turn from forms standing very low in the 
mammalian series. 

The Marsupials stand in many important characters below 
the placental mammals. They appeared at an earlier geologi- 
cal period, and their range was formerly much more extensive 
than at present. Hence the Placentata are generally supposed 

*• *' Elements of Geology," 1865, pp. 583« *" " Man's Place in Nature." p. io> 
485. " Antiquity of Man,'^ 1863, p. 145. 

174 THE DESCENT OF MAN. {part t 

to have been derived from the Implacentata or Marsupials ; 
not, however, from forms closely resembling the existing Mar- 
supials, but from their early progenitors. The Monotremata 
are plainly allied to the Marsupials, forming a third and still 
lower division in the great mammalian series. They are repre- 
sented at the present day solely by the Ornithorhynchus and 
Echidna; and these two forms may be safely considered as 
relics of a much larger group representatives of which have 
been preserved in Australia through some favorable concur- 
rence of circumstances. The Monotremata are eminently in- 
teresting, as leading in several important points of structure 
toward the class of reptiles. 

In attempting to trace the genealogy of the Mammalia, and 
therefore of man, lower down in the series, we become involved 
in greater and greater obscurity ; but, as a most capable judge, 
Mr. Parker, has remarked, we have good reason to believe 
that no true bird or reptile intervenes in the direct line of de- 
scent. He who wishes to see what ingenuity and knowledge 
can effect, may consult Prof Hackel's works. ^^ 1 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, espe- 
cially during their embryonic state. As the class of fishes is 
the most lowly organized, and appeared before the others, we 
may conclude that all the members of the vertebrate kingdom 
are derived from some fish-like animal. The belief that an- 
imals so distinct as a monkey, an elephant, a humming-bird, 
a snake, a frog, and a fish, etc., could all have sprung from 
the same parents, will appear monstrous to those who have not 
attended to the recent progress of natural history. For this 
belief implies the former existence of links binding closely to- 
gether all these forms, now so utterly unlike. 

Nevertheless, it is certain that groups of animals have ex- 
isted, or do now exist, which serve to connect several of the 
great vertebrate classes more or less closely. We have seen 
that the Ornithorhynchus graduates toward reptiles ; and Prof, 
tluxley has discovered, and is confirmed by Mr. Cope and 

9* Elaborate tables are giien in his 42), says, that he considers the phylum or 

*' Generelle Morphologie " (B. ii s. cliii. and lines of descent of the Vertebrata to be ad- 

s. 425) ; and with more especial r'nferenre to mirably discussed by Hackel, although he 

man in liis " Natiirliche Schoj^fungsge- dififers on some points. He expresses, also, 

schichte," 1868. Prof. Huxley, in reviewing his high estimate of the general tenor an4 

ttiis latter work (" The Academy," 1869, p. spirit of the whole work. 


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 langer group) and the Archeop- 
teryx, that strange Secondary bird, with a long lizard-like tail. 
Again, according to Prof. Owen,''^'^ the Ichthyosaurians — great 
sea-lizards furnished with paddles — present many affinities with 
fishes, or rather, according to Huxley, with amphibians: a 
class which, including in its highest division frogs and toads, 
is plainly allied to the Ganoid fishes. These latter fishes 
swarmed during the earlier geological periods, and were con- 
structed on what is called a generalized type, that is, they 
presented diversified affinities with other groups of organisms. 
The Lepidosiren is also so closely allied to amphibians and 
fishes, that naturalists long disputed in which of these two 
classes to rank it ; it, and also some few Ganoid fishes, have 
been preserved from utter extinction by inhabiting rivers, 
which are harbors of refuge, and are related to the great waters 
of the ocean in the same way that islands are to continents. 

Lastly, one single member of the immense and diversified 
class of fishes, namely, the lancelet or amphioxus, is so 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, etc. ; so that it 
was classed by the older naturalists among the worms. Many 
years ago Prof. Goodsir perceived that the lancelet presented 
some affinities with the Ascidians, which are invertebrate, 
hermaphrodite, marine creatures 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 MoUuscoida of Huxley — a lower division 
of the great kingdom of the Mollusca ; but they have recently 
been placed by some naturalists among the Vermes or worms. 
Their larvae somewhat resemble tadpoles in shape,^ and have 
the power of swimming freely about. M. Kovalevsky^ has 
lately observed that the larvae of Ascidians are related to the 

'' " Palaeontology," i860, p. 199. filament. It was, as sketched by me, under 

"At the Falkland Islands I had the a simple microscope, plainly divided by 

satisfaction of seeing, in April, 1833, and transverse opaque partitions, which I pie- 

therefore some years before any other nat- sume represent the great cells figured by 

uralist, the locomotive larvae of a compound Kovalevsky. At an early stage of develop 

Ascidian, closely allied to Synoicum, but menl the tail was closely coiled round the 

apparently generically distinct from it. The head of the larva. 

tail was about five times as long as the ob- '♦ " Memoires de I'Acad. des Sciences 

|pa| head, and terminated in a very fine dc St. P^tersbourg," torn, x., No. 15, 1866, 

176 rilE DESCENT OF MAM. [part l 

Vcrtebrata 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 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 great- 
est value. Thus, if we may rely on embryology, ever the safest 
guide in classification, it seems that we have at last gained a 
clew to the source whence the Vertebrata were derived.^ We 
should then be justified in believing that at an extremely re- 
mote 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 Vertebrata. 

We have thus far endeavored rudely to trace the genealogy 
of the Vertebrata by the aid of their mutual affinities. We will 
now look to man as he exists ; and we shall, I think, be able 
partially to restore the structure of our early progenitors, during 
successive periods, but not in due order of time. This can be 
effected by means of the rudiments which man still retains, by 
the characters which occasionally make their appearance in 
him through reversion, and by the aid of the principles of 
morphology and embryology. The various facts to which I 
shall here allude have been given in the previous chapters. 

The early progenitors of man must have been once covered 
with hair, both sexes having beards ; their ears were probably 
pointed, and capable of movement; and their bodies were 
provided 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 
Quadrumana. At this or some earlier period, the great artery 
and nerve of the humerus ran through a supra-condyloid fora- 
men. The intestine gave forth a much larger diverticulum or 
caecum than that now existing. The foot was then prehensile, 

2* But I am bound to add that some com- nature peut produire la disposition fonda- 

petent judges dispute this conclusion ; for mentale du type vertebre (rexistence d'une 

instance, M. Giard, in a series of papers in corde dorsale) chez un invertebre par la 

the " Archives de Zoologie Experimentale," seule condition vitale de I'adaptation, et 

for 1872. Nevertheless, this naturalist re- cette simple possibilite du passage supprime 

marks, p. 281, " L' organisation de la larve I'abime entre les deux sous-r^gnes, encore 

ascidienne en dehors de toute hypothese et bien qu' on ignore par QU k passage s'esttsi^ 

4etoute throne, nous niontr^ comment la en r^alit^." 


judging from the condition of the great toe in the foetus ; and 
our progenitors, no doubt, were arboreal in their habits, and 
frecjuented some warm, forest-clad land. The males had great 
canine teeth, which served them as formidable weapons. At 
a much earlier period the uterus was double ; the excreta were 
voided through a cloaca ; and the eye was protected by a third 
eyehd or nictitating membrane. At a still earlier period the 
progenitors of man must have been aquatic in their habits \ 
for morphology plainly tells us that our lungs consist of a 
modified swim-bladder, which once served as a float. The 
clefts on the neck in the embryo of man show where the 
branchiae once existed. In the lunar or weekly recurrent 
periods of some of our functions we apparently still retain 
traces of our primordial birthplace, a shore washed by the 
tides. At about this same early period the true kidneys were 
replaced by the corpora wolffiana. The heart existed as a 
simple pulsating vessel \ and the chorda dorsalis took the place 
of a vertebral column. These early ancestors of man, thus seen 
in the dim recesses of time, must have been as simply, or even 
still more simply organized than the lancelet or amphioxus. 

There is one other point deserving a fuller notice. It ha^ 
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 ap- 
pears 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 pas- 
sage, in their vesiculse prostaticae ; they bear also rudiments of 
mammae, and some male Marsupials have traces of a marsupial 
sac.^' Other analogous facts could be added. Are we, then, 
to suppose that some extremely ancient mammal continued 
androgynous, after it had acquired the chief distinctions of its 
class, and therefore after it had diverged from the lower classes 
of the vertebrate kingdom ? This seems very improbable, for 

*• This is the conclusion of Prof. Gegen- the sexual organs of even "the higher verte- 

baur, one of the highest authorities in com- brata are, in their early condition, hermaph- 

paratiye anatomy ; see " Grundziige der rodite." Similar views have long been 

vergleich. Anat.," 1870. s. 876 The result held by some authors, though until recently 

has been arrived at chiefly from the study of without a firm basis. 

the Amphibia ; but it appears from the re- '•*' The male I'hylacinMs offers the best 

searches of Waldeyer (as quoted in " Jour- instance. Owen, "Anatomy of VcrtC- 

Qaiof Anat. and Phys.," 1869, p. 161), that brates," vol iii. p. 771. 

178 THE DESCENT OF MAM, [part t 

we have to look to fislies, the lowest of all the classes, to find 
any still existent androgynous forms.*' That various accessory 
parts, proper to each sex, are found in a rudimentary con- 
dition in the opposite sex, may be explained by such organs 
having been gradually ac(piired by tlic one sex, and then trans- 
mitted in a more or less imperfect state to the other. When 
we treat of sexual selection we shall meet with innumeral^le 
instances of this form of transmission — as in the case of the 
spurs, plumes, and brilliant colors, acquired for battle or orna- 
ment by male birds, and inherited by the females in an imper- 
fect or rudimentary condition. 

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 ori- 
fices, but no nipples ; and as these animals stand at the very 
base of the mammalian series, it is probable that the progeni- 
tors 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 Prof. Turner informs me, on the author- 
ity of Kolliker and Langer, that in the embryo the mam- 
mary glands can be distinctly traced before the nipples are in 
the least visible ; and the development of successive parts in 
the individual generally represents and accords with the devel- 
opment 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 Mar- 
supials, 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 re- 
mained 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. 

'* Hermaphroditism has been observed in ranus. Prof. Ercolani has recently shown 
several species of Serranus, as well as in ("Accad. delle Scienze," Bologna, Dec. 28, 
some other fishes, where it is either normal 1871) that eels are androgj'nous. 
and symmetrical or abnormal and uni- '^'^ Prof. (Jegenhaur has shown ("Jena- 
lateral. Dr. Zouteveen has given me refer- ischc Zeitschrift," tSd. vii. p. 212) that two 
ences on this subject, more especially to a distinct types of nipples prevail throiigl.out 
paper by Prof. Halbertsma, in the "Trans- the several mammalian orders, but that it 
act. of the Dutch Acad, of Sciences," vol. is quite intelligible h->w both could have Lecu 
jfvi. Dr. Giinther doubts the fact, but it derived from the nipv^'es of the Marsupials, 
has now been recorded by too many good and the latter from tfose of the M >n'.iit- 
observers to be any longer disputed. Dr. mata. See, also, a ir^emoir by I -'r M i^ 
M. Lessona writes to me that he has verified Huss. on the matORi^ry glands, ibid., ii. .tUi 

the observations made by CavoUni or. Svr- p, 176. 


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 car- 
ried their young in marsupial sacs. This will not appear 
altogether improbable, if we reflect that the males of existing 
syngnathous fishes receive the eggs of the females in their ab- 
dominal pouches, hatch them, and afterward, as some believe, 
nourish the young ; ^ that certain other male fishes hatch the 
eggs within their mouths or branchial cavities ; that certain 
male toads take the chaplets of eggs from the females, and 
wind them round their own thighs, keeping them there until 
the tadpoles are born ; that certain male birds undertake the 
whole duty of incubation, and that male pigeons, as well as 
the females, feed their nestlings with a secretion from their 
crops. But the above suggestion first occurred to me from the 
mammary glands of male mammals being so much more per- 
fectly developed than the rudiments of the other accessory re- 
productive 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 rudimen- 
tary ; they are merely not fully developed, and not function- 
ally active. They are sympathetically afiected under the in- 
fluence of certain diseases, like the same organs in the female. 
They oftea 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 dur- 
ing a former prolonged period male mammals aided the 
females in nursing their oflspring,^^ and that afterward from 
some cau-e (as from the production of a smaller number of 
young) tne 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 

•"^ Mr. Lockwood believes (as quoted in Boston Soc. of Nat Hist.," Sept. 15, 1857; 

•'Quart. Journal of Science," April, 1868, also Prof. Turner, in "Journal of Anat. and 

p. 269), from what he has observed of the Phys.," Nov. i, 1866, p. 78. Dr. Giinther 

development of Hippocampus, that the walls has likewise described similar cases, 

of the abdominal pouch of the male in some ^* Mdlle. C. Royer has suggested a sim- 

way afford nourishment. On male fishes ilar view in her **Ongine dc rHonuBCi'' 

hatching the ova in their mouths, see a very etc, 1S70. 
interesting paper by Prof. Wvinan, in "Prou 

^80 THE DESCENT OF MAN, [part i. 

c:orres[)onding age of maturity. But at an earlier age these 
organs would be left unaffected, so that they would be almost 
equally well developed in the young of both sexes. 

Conclusion. — Von Baer has defined advancement or progress 
in the organic scale better than any one else, as resting on the 
amount of differentiation and specialization of the several parts 
of a being — when arrived at maturity, as I should be in- 
clined to add. Now as organisms have become slowly 
adapted to diversified lines of life by means of natural selection, 
their parts will have become more and more differentiated and 
specialized for various functions, from the advantage gained 
by the division of physiological labor. The same part appears 
often to have been modified first for one purpose, and then long 
aftervv'ard 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 pro- 
genitor from which it was aboriginally derived. In accord- 
ance with this view it seems, if we turn to geological evidence, 
that organization on the whole has advanced throughout the 
woild by slow and interrupted steps. In the great kingdom of 
the Vertebrata it has culminated in man. It must not, how- 
ever, be supposed that groups of organic beings are alwaj-s 
supplanted, and disappear as soon as they have given birth to 
other and more perfect groups. The latter, though victorious 
over their predecessors, may not have become better adapted 
for all places in the economy of nature. Some old forms ap- 
pear to have surviv^ed 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 organized group as perfect representatives of their an- 
cient predecessors. 

The most ancient progenitors in the kingdom of the Verte- 
brata, at which we are able to obtain an obscure glance, ap- 
parently consisted of a group of marine animals,^'^ resembling 

^2 The inhabitants of the seashore must to run their course in regular weekly periods, 
be greatly affected by the tides ; animals Nr-v it is a mysterious fact that in the 
living either about the vtcati high-water higher and now terrestrial Vertebrata, as 
niark, or about the mean low-water mark, well as in other classes, many normal and 
pass througli a complete cycle of tidal abnormal processes have one or more whole 
changes in a fortnight. Consequently, weeks as their periods : this would be ren- 
their food supply will undergo marked dered intelligible if the Vertebrata are de- 
changes week by week. The vital functions scended from an animal allied to the exist- 
of such animalS; living under these condi- ing tidal Ascidians. Many instances of 
Uons for many generations, can hardly fail such periodic processes might be given, at 


the larvae of existing Ascidians. These animals probably gave 
rise to a group of fishes, as lowly organized as the lancelet ; and 
from these the Ganoids, and other fishes like the Lepidosiren, 
must have been developed. From such fish a very small advance 
would carry us on to the Amphibians. We have seen that 
birds and reptiles were once intimately connected together ; 
and the Monotremata now connect mammals with reptiles in a 
slight degree. But no one can at present say by what line of 
descent the three higher and related classes, namely, mammals, 
birds, and reptiles, were derived from the two lower vertebrate 
classes, namely, amphibians and fishes. In the class of mam- 
mals the steps are not difficult to conceive which led from the 
ancient Monotremata to the ancient Marsupials; and from 
these to the early progenitors of the placental mammals. We 
may thus ascend to the 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 mon- 
keys ; and from the latter, at a remote period, Man, the won- 
der and glory of the Universe, proceeded. 

Thus we have given to man a pedigree of prodigious length, 
but not, it may be said, of noble quality. The world, it has 
often been remarked, appears as if it had long been preparing 
for the advent of man ; and this, in one sense, is strictly true, 
for he owes his birth to a long line of progenitors. If any sin- 
gle 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 rec- 
ognize our parentage ; nor need we feel ashamed of it. The 
most humble organism is something much higher than the in- 
organic 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 

the gestation of mammals, the duration of gained, be liable to change ; consequently 

fevers, etc. The hatching of eggs affords it might be thus transmitted through almost 

also a good example, for, according to Mr. any number of generations. But if the 

Bartlett (" Land and Water," Jan. 7, 1871), function changed, the period would have to 

the eggs ol the pigeon are hatched in two change, and would be apt to change almost 

weeks; those of the fowl in three; those of abruptly by a whole week. This conclusion, 

the duck in four ; those of the goose in five ; if sound, is highly remarkable ; for the peri- 

and those of the ostrich in seven weeks. As od of gestation in each mammal, and the 

far as we can judge, a recurrent period, if hatching of each bird's eggs, and many 

approximately of the right duration for any other vital processes, thus betray to us thc 

process or function, would not, when once primotdial birthplace of these anuaaU. 




The natuie and value of specific characters — Application to the races of 

man — Arguments in favor of, and opposed to, ranking the so-called 
races of man as distinct species — Sub-species — Monogenists and 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 of races 
— The effects of crossing — Slight influence of the direct action of the 
conditions of life — Slight or no influence of natural selection — Sexual 

It is not my intention here to describe the several so-called 
races of men ; but I am about to inquire what is the value of 
the differences between them under a classificatory point of 
view, and how they have originated. In determining whether 
two or more allied forms ought to be ranked as species or va- 
rieties, naturalists are practically guided by the following con- 
siderations, 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 shown, or rendered probable, that the 
forms in question have remained distinct for a long period, 
this becomes an argument of much weight in favor of treating 
them as species. Even a slight degree of sterility betv/een any 
two forms when first crossed, or in their offspring, is generally 
considered as a decisive test of their specific distinctness ', and 
their continued persistence without blending within the same 
area is usually accepted as sufficient evidence, either of some 
degree of mutual sterility, or, in the case of animals, of some 
mutual repugnance to pairing. 

Independently of fusion from intercrossing, the complete 
absence, in a well-investigated region, of varieties linking to- 
gether any two closely allied forms, is probably the most im- 
portant 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 of the other inhabitants are specifically distinct, are them- 
selves usually looked at as distinct ; but in truth this affords no 
aid in distinguishing geographical races from so-called good or 
true species. 

Now let us apply these generally admitted principles to the 
races of man, viewing him in the same spirit as a naturalist 
would any other animal. In regard to the amount of differ- 
ence between the races, we must make some allowance for our 
nice powers of discrimination gained by the long habit of ob- 
serving 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 supposed ; certain negro tribes must be excepted, while 
others, as Dr. Rohlfs writes to me, and as I have myself seen, 
have Caucasian features. This general similarity is well shown 
by the French photographs in the Collection Anthropologique 
du Museum de Paris of the men belonging to various races, the 
greater number of which might pass for Europeans, as many 
persons to whom I have shown them have remarked. Never- 
theless, these men, if seen alive, would undoubtedly appear 
very distinct, so that we are clearly much influenced in our 
judgment by the mere color of the skin and hair, by slight dif- 
ferences 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. 3 But it would be an endless task to specify the numer- 
ous points of difference. The races differ also in constitution, 
in acclimatization, and in liability to certain diseases. Their 
mental characteristics are likewise very distinct ; chiefly as it 

' " History of India," 1841, vol. i. p. 323. the capacity of the lungs," p. 471. See also 

Father Ripa makes exactly the same remark the numerous and valuaWe tables, by Dr. 

with respect to the Chinese. Weisbach, from the observations of Dr. 

'•'A vast number of measurements of Scherzer and Dr. Schwarz in the " Reiseder 

Whites, I'lacks. and Indians are given in Novara : Anthropolog. I'heil," 1867. 

the " Investigations in the Military and An- 3 Sgg^ for instance, Mr. Marshall's ac 

thropolog. Statistics of American Soldiers." coimt of the brain of a Bushwoman, IQ 

byB. A. Gould, 1869, pp. 298-356; "On " PbU. Transact.," 1864, p. 519. __. 

1 84 THE DESCENT OF MAN, Ifakt l 

would appear in their emotional, but partly in their intellectual 
faculties. Iweryone who has had the opportunity of compari- 
son must have been struck v/ith the contrast between the taci- 
turn, even morose, aborigines of South America and the light- 
hearted, talkative negroes. There is a nearly similar contrast 
between the Malays and the Papuans,* who live under the same 
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 favor of classing the races of man as distinct species, and 
then the arguments on the other side. If a naturalist, who 
had never before seen a Negro, Hottentot, Australian, or Mon- 
golian, 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 inquiry he would find 
that they were adapted to live under widely different climates, 
;in d that they differed somewhat in bodily constitution and 
mental disposition. If he were then told that hundreds of 
similar specimens could be brought from the same countries, 
he would assuredly declare that they were as good species as 
many to which he had been in the habit of affixing specific 
names. This conclusion would be greatly strengthened as 
soon as he had ascertained that these forms had all retained the 
same character for many centuries ; and that negroes, appar' 
ently identical with existing negroes, had lived at least 4,000 
years ago.^ He would also hear, on the authority of an excel- 
lent observer, Dr. Lund,^ that the human skulls found in the 
caves of Brazil, entombed v/ith many extinct mammals, be- 
longed to the same type as that now prevailing throughout the 
American Continent. 

Our naturalist would then perhaps turn to geographical dis- 

* Wallace, "The Malay Archipelago,'* man {" Races of Man," 1850, p. 201), speak- 

vol. ii., 1869, p. 178. ing of young Memnon (the same as Ra- 

** With respect to the figures in the famous meses II., as I am informed by Mr. Birch), 

Egj-ptian caves of Abou-Simbel, M. Pouchet insists in the strongest manner that he is 

says (" The Plurality of the Human Races," identical in character with the Jews of Ant- 

Eng. translat., 1864, p. 50), that he was far werp. Again, when I looked at the sta- 

from finding recognizable representations of tue of Amunoph III., I agreed with two 

the dozen or more nations which some au- officers of the establishment, both competent 

'hers believe that they can recognize. Even judges, that he had a strongly marked ne- 

some of the most sirongly marked races gro type of features ; but Messrs. Nott and 

cannot be identified with that degree of Gliddon (ibid., p. 146, fig. 53) describe him 

unanimity which might have been expected as a hybrid, but not of " negro intermixt- 

fi-om what has been written on the subject, ure." 

Thus Messrs, Nott and Gliddon ("Types ^ As quoted by Nott and Gliddon, "Types 

of Mankind," p. 148) state that Rameses II., of Mankind," 1854, p. 439. They give also 

or the Great, has features superbly Euro- coirohorative evidence ; but C. Vogt thinks 

pean ; whereas Knox, another firm believer that the subject requires further iavestigs- 

ID th« specific distinctness qf the races of tion^ 


tribution, and he would probably declare that those forms must 
be distinct species which differ not only in appearance, but are 
fitted for hot as well as damp or dry countries, and for the 
Arctic regions. He might appeal to the fact that no species in 
the group next to man, namely, the Quadrumana, can resist a 
low temperature, or any considerable change of climate ; and 
that the species which come nearest to man have never been 
reared to maturity, even under the temperate climate of Europe, 
He would be deeply impressed with the fact, first noticed by 
Agassiz,*^ 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 Hot- 
tentots ; but plainly with the Papuans and Malays, who are 
separated, as Mr. Wallace has shown, by nearly the same line 
which divides the great Malayan and Australian zoological 
provinces. The Aborigines of America range throughout the 
Continent ; and this at first appears opposed to the above rule, 
for most of the 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 zoo- 
logical provinces does not correspond with the degree of separa- 
tion 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 ot 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. 

, ' *' Diversity of Origin of the Human Races," in the " Christian Exammcr July, 1830- 

1 86 THE DESCENT OF MAN. [part l 

Murray has carefully examined the Pediculi collected in differ- 
ent countries from the different races of man ; ^ and he finds that 
they differ not only in cok)r, but in the structure of their claws 
and limbs. In every case in which many specimens were ob- 
tained the differences were constant. The surgeon of a whaling 
ship in the Pacific assured me that when the Pediculi with 
which some Sandwich Islanders on board swarmed, strayed on 
to the bodies of the English sailors, they died in the course of 
three or four days. These Pediculi were darker colored, and 
appeared different from those proper to the natives of Chiloe, in 
South America, of which he gave me specimens. These, again, 
appeared larger and much softer than European lice. Mr. 
Murray procured four kinds from Africa, namely, from the 
Negroes of the Eastern and Western coasts, from the Hottentots 
and Kaffirs; two kinds from the natives of Australia; two from 
North and two from South America. In these latter cases it 
may be presumed that the Pediculi came from natives inhab- 
iting different districts. With insects sHght structural differ- 
ences, 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 dis- 
tinct species. 

Our supposed naturalist, having proceeded thus far in his in- 
vestigation, would next inquire v/hether the races of men, when 
crossed, were in any degree sterile. He might consult the work^ 
of Prof. Broca, a cautiorj and philosophical observer, and in 
this he would find good Ovidence 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 shown 
to be almost valueless. The half-castes are killed by the pure 
blacks : and an account has lately been published of eleven half- 
caste youths murdered and burnt at the same time, whose re- 
mains were found by the police. ^^ Again, it has often been 
said that when mulattoes intermarry they produce few children ; 

• '• Transact. R. Soc. of Edinburgh," vol. who have borne children to a white ina« 

xxii., 1861, p. 567. are afterward sterile with their own race, is 

® "On the Phenomena of Hybridity in disproved. M. A. de Quatrefages has also 

the Genus Hoino," Eng. translat., 1864 collected (" Revue des Cours Scientifiques," 

''■' See the interesting letter by Mr. T. A. March, 1869, p. 239) much evidence that 

Murray, in the " Aiithropolcg. Reviev/," Australians and Europeans are not §tcrile 

April, 186P, p. liii. In t!;'s letter Count when crossedt 
Strz^lecki's statement.that Australian women 


on the other hand, Dr. Bachman, of Charleston,"" positively as- 
serts that he has known mulatto families which have intermarried 
for several generations, and have continued on an average as 
fertile as either pure whites or pure blacks. Inquiries formerly- 
made by Sir C. Lyell on this subject led him, as he informs me, 
to the same conclusion. ^^ In the United States the census for 
the year 1854 included, according to Dr. Bachman, 405,751 
mulattoes; and this number, considering all the circumstances 
of the case, seems small ; but it may partly be accounted for by 
the degraded and anomalous position of the class, and by the 
profligacy of the women. A certain amount of absorption of 
mulattoes into negroes must always be in progress; and this 
would lead to^an ai)parent diminution of the former. The in- 
ferior vitality of mulattoes is spoken of in a trustworthy work^^ 
as a well-known phenomenon ; and this, although a different 
consideration from their lessened fertility, may perhaps be 
advanced as a proof of the specific distinctness of the parent 
races. No doubt both animal and vegetable hybrids, when 
produced from extremely distinct species, are liable to pre- 
mature death ; but the parents of mulattoes cannot be put 
under the category of extrem.ely distinct species. The com- 
mon Mule, so notorious for long life and vigor, and yet so 
sterile, shows how little necessary connection there is in hy- 
brids 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 
chat fertility and sterility are not safe criterions of specific dis- 
tinctness. We know that these qualities are easily affected by 
changed conditions of life, or by close interbreeding, and tha^ 
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 

** "An Examination of Prof. Agassiz's maxim that mulattoes should not intermarry. 

Sketch of the Nat. Provinces of the Animal as the children are few and sickly. This be- 

World," Charleston. 1855, p. 44. lief, as Mr. Reade remarks, deserves atten- 

'^ Dr. Rohlfs writes to me that he found tion. as white men have visited and resided 

the mixed races in the Great Sahara, de- on the Gold Coast for four hundred years, so 

rived from Arabs, lU-rhers. and Negroes of that the natives have had ample time to gain 

three tribes, extraordinarily fertile. On the knowledge through experience, 
other hand, Mr. Winwood Re.nde informs me '^ "Military and Anthropolog. Statistics 

that the negroes on the (Jold Coast, though of American Soldiers," by B. A. Gould, 

admiring white men and mulattoes, have a 1S69, p. 319. 

loo THE DESCENT OF MAN". Ipart i. 

fertile. The degrees of sterility do not coincide strictly with 
the degrees of difference between the parents in external struct- 
ure or hal)its 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 favor of the Pal- 
lasian 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 established, would not absolutely preclude us from 
ranking them as distinct species. 

Independently of fertility, the characters presented by the 
offspring from a cross have been thought to indicate whether 
or not the parent-forms ought to be ranked as species or 
varieties ; but, after carefully studying the evidence, I have 
come to the conclusion that no general rules of this kind can 
be trusted. The ordinary result of a cross is the production of 
a blended or intermediate form ; but in certain cases some of 
the offspring take closely after one parent-form, and some after 
the other. This is especially apt to occur when the parents 
differ in characters which first appeared as sudden variations or 
monstrosities. 1^ I refer to this point because Dr. Rohlfs in- 
forms 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 

'* "The Variation of Animals and Plants be augmented by the preservation or sur- 
under Domestication," vol. ii. p. 109. I viva! of the more and more sterile individ* 
may here remind the reader that the sterility uals; for as the sterility increases, fewer and 
of species when crossed is not a specially fewer offspring will be produced from which 
acquired quality, but, like the incapacity of to breed, and at last only single individuals 
certain trees to be grafted together, is mci- will be produced, at the rarest intervals, 
dental on other acquired differoca9<s. The But there is even a higher grade of sterility 
nature of these differences is unknown, but than this. Both Gartner and Kolreuter 
they relate more especially to the rcproduc- have proved that in genera of plants includ- 
tive system, and much less so to external iog many species, a series can be formed 
structure or to ordinary differences in consti- from species which when crossed yield fewer 
tution. One important element in the ste- and fewer seeds, to species which never pro- 
rility of crossed species apparently lies in duce a single seed, but yet are affected by 
one or both having been long habituated to the pollen of the other species, as shown by 
fixed conditions ; for we know that changed the swelling of the germ.en. It is here mam- 
conditions have a special influence on the festly impossible to select the more sterile 
reproductive system, and we have good rea- Individuals, which have already ceased to 
son to believe (as before remarked) that the yield seeds; so that the acme of sterility, 
fluctuating conditions of domestication tend when the germen alone is affected, cannot 
to eliminate that sterility which is so general have been gained through selection. This 
with species, in a natural state, when crossed, acme, and no doubt the other grades of 
It has elsewhere been shown by me (ibid., sterility', are the incidental results of certain 
vol. ii. p. 185, and "Origin of Species," 5th unknown differences in the constitution of the 
edit, p. 317), that the sterility of crossed spe- reproductive system of the species which are 
cies has not been acquired through natural crossed. 

selection : we can see that when two forms -^ "The Variation of Animals," etc., v«L 

have already been rendered very sterile, it ii. p. 92. 
is Sv^rcdy possible that their sterility should 


hand, it is notorious that in America mulattocs commonly 
present an intermediate ai)pearance. 

We have now seen that a naturahst 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 with the distribution 
of the several so-called races, which accords with that of other 
undoubtedly distinct species of mammals. Finally, he might 
urge that the mutual fertility of all the races has not as yet 
been fully proved, and even if proved would not be an absolute 
proof of their specific identity. 

On the other side of the question, if our supposed naturalist 
were to inquire whether the forms of man keep distinct like 
ordinary species, when mingled together in large numbers in 
the same country, he would immediately discover that this was 
by no means the case. In Brazil he would behold an immense 
mongrel population of Negroes and Portuguese ; in Chiloe and 
other parts of South America he would behold the whole 
population consisting of Indians and Spaniards blended in 
various degrees.^*' In many parts of the same continent he 
would meet with the most complex crosses between Negroes, 
Indians, and Europeans ; and, judging from the vegetable king- 
dom, such triple crosses afford the severest test of the mutual 
fertility of the parent-forms. In one island of the Pacific he 
would find a small population of mingled Polynesian and Eng- 
lish blood ; and in the Fiji Archipelago a population of Poly- 
nesian and Negritos crossed in all degrees. Many analogous 
cases could be added ; for instance, in Africa. Hence the 
races of man are not sufficiently distinct to inhabit the same 
country without fusion ; and the absence of fusion affords the 
usual and best test of specific distinctness. 

Our naturalist would likewise be much disturbed as soon as 
he perceived that the distinctive characters of all the races 
were highly variable. This fact strikes everyone c n first be- 

'• M. de Quatrefages has given (" Anthro- of the Paullstas in l?razil, who are a much- 

Eklog. Review," January, 1869, p. 22) an crossed race of Portuguese a;' d Indians, wilb 
teresting accoiwt «C the success and energy a mixture of the blood of otlier races. 

igO THE DESCENT OF MAN". [part l 

holding the negro slaves in Brazil, who have been imported 
from all parts of Africa. The same remark holds good with 
the Polynesians, and with many other races. It may be doubted 
whether any character can be named which is distinctive of a 
race and is constant. Savages, even within the limits of the 
same tribe, are not nearly so uniform in character as has been 
often asserted. Hottentot women offer certain peculiarities, 
more strongly marked than those occurring in any other race, 
but these are known not to be of constant occurrence. In the 
several American tribes, color and hairiness differ considerably ; 
as does color to a certain degree, and the shape of the features 
greatly, in the Negroes of Africa. The shape of the skull varies 
much in some races ;^'^ and so it is with every other character. 
Now all naturalists have learned by dearly bought experience 
how rash it is to attempt to define species by the aid of incon- 
stant characters. 

But the most weighty of all the arguments against treating 
the races of man as distinct species is that they graduate into 
each other, independently in many cases, as far as we can 
judge, of their having intercrossed. Man has been studied 
more carefully than any other animal, and yet there is the 
greatest possible diversity among capable judges whether he 
should be classed as a single species or race, or as two (Virey), 
as three (Jacquinot), as four (Kant), five (Blumenbach), six 
(Buffon), seven (Hunter), eight (Agassiz), eleven (Pickering), 
fifteen (Bory St. Vincent), sixteen (DesmouHns), twenty-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 species, but it shows that they 
graduate into each other, and that it is hardly possible to dis- 
cover clear distinctive characters between them. 

Every naturalist who has had the misfortune to undertake the 
description of a group of highly varying organisms has en- 
countered cases (I speak after experience) precisely like that of 
man, and if of a cautious disposition, he will end by uniting 
all the forms which graduate into each other under a single 
species ; for he will say to himself that he has no right to give 
names to objects which he cannot define. Cases of this kind 
occur in the Order which includes man, namely, in certain 

" For instance with the aborigines of '^ See a good discussion on this subject 

America and Australia. Prof. Huxley says in Waltz. " Introduct. to Anthropology," 

("Transact. Internat. Congress of Prehlst. Eng. translat., 1S63, pp. 198-208, 227. I 

Arch.," 186S, p. 105) that the skulls of many have taken some of the above statements 

South Germans and Swiss are "as short from H. Tuttle's "Origin and Antiquity of 

and as broad as those of the Tartars." etc Physical Man," Boston, 1866, p. 35. _, 


genera of monkeys ; while in other genera, as in Cercopithecns, 
most of the species can be determined with certainty. In the 
American genus Cebus, the various forms are ranked by some 
naturahsts as species, by others as mere geographical races. 
Now if numerous specimens of Cebus were collected from all 
parts of South America, and those forms which at present ap- 
pear 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. Neverthe- 
less, it must be confessed that there are forms, at least in the 
vegetable kingdom, ^^ which we cannot avoid naming as species, 
but which are connected together by numberless gradations, in- 
dependently of intercrossing. 

Some naturalists have lately employed the term ^'sub- 
species ' ' to designate forms which possess many of the charac- 
teristics 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 difficulties on the other side in defining 
them, it seems that the term *' sub-species " might here be used 
with propriety. But from long habit the term ''race" will 
perhaps always be employed. The choice of terms is only so 
far important in that it is desirable to use, as far as possible, 
the same terms for the same degrees of difference. Un- 
fortunately this can rarelv be done : for the larger genera gen. 
erally include closely allied forms, which can be distinguished 
only with much difficulty, while the smaller genera within the 
same family include forms that are perfectly distinct ; yet all 
must be ranked equally as species. So again, species within 
the same large genus by no means resemble each other to the 
same degree ; on the contrary, some of them can generally be 
arranged in little groups round other species, like satellites 
round planets.^ 

The question whether mankind consists of one or several 
species has of late years been much discussed by anthropolo- 
gists, who are divided into the two schools of monogenists and 
polygenists. Those who do not admit the principle of evolu- 
tion must look at species as separate creations, or as in some 

'^ Prof. Nagell has carefully described some intermediate forms in the Compositx 

several striking cases in his " Botanische of North America. 

^ittheilupgen," B. ii., 1866, s. 294-369. Prof. '■*" " Origin of Species," sth edit... p. 68. 
A«sa Gray h?is made analogous remarks on 

tg2 THE DESCENT OE MAN: [part I. 

manner as distinct entities; and they must decide what forms 
of man they will consider as species by tlic analogy of the 
method commonly pursued in ranking other organic beings as 
species. Va\\. it is a hoi)elcss endeavor to decide this point, 
until some defmition of the term "species" is generally ac- 
cepted ; and the defmition must not include an indeterminate 
element such as an act of creation. We might as well attem])t 
without any definition to decide whether a certain number of 
houses should be called a village, town, or city. We have a 
practical illustration of the difficulty in the never-ending doubts 
whether many closely allied mammals, birds, insects, ana 
plants, which represent each other respectively in North Amer- 
ica and Europe, should be ranked as species or geographical 
races ; and the like holds true of the productions of many vA- 
ands situated at some little distance from the nearest conti- 

Those naturalists, on the other hand, who admit the prin- 
ciple of evolution, and this is now admitted by the majority of 
rising men, will feel no doubt that all the races of man are de- 
scended from a single primitive stock ; whether or not they 
may think fit to designate the races as distinct species, for the 
sake of expressing their amount of difference.^^ With our do- 
mestic animals the question whether the various races have 
arisen from one or more species is somewhat different. Al- 
though 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 
from a common stock, the differences between the races and 
their number must have been small; consequently, as far as 
their distinguishing characters are concerned, they then had 
less claim to rank as distinct species than the existing so-called 
races. Nevertheless, so arbitrary is the term of species, that 
such early races would perhaps have been ranked by some 
naturalists as distinct species, if their differences, although ex- 

■1 See Prof, Huxley to this effect in the " Fortnightly Review," 1865, p. 375. 


tremely slight, had been more constant than they are at 
present, and liad not graduated into each other. 

It is however possible, though far from probable, that llie 
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 
offspring of two distinct species for the same object, ne some- 
times induces a considerable amount of convergence, as far as 
general appearance is concerned. This is the case, as shown by 
Von Nathusius,^' with the improved breeds of the pig, which 
are descended from two distinct species ; and in a less marked 
manner with the improved breeds of cattle. A great anatom- 
ist, Gratiolet, maintains that the anthropomorphous apes do 
not form a natural sub-group ; but that the orang is a highly 
developed gibbon or semnopithecus, the chimpanzee a highly 
developed macacus, and the gorilla a highly developed mandrill. 
If this conclusion, which rests almost exclusively on brain- 
characters, be admitted, we should have a case of convergence, 
at least in external characters, for the anthropomorphous apes 
are certainly more like each other in many points than they are 
to other apes. All analogical resemblances, as of a whale to a 
fish, may indeed be said to be cases of convergence ; but this 
term has never been applied to superficial and adaptive resem- 
blances. It would, however, be extremely rash to attribute to 
convergence close similarity of character in many points of 
structure among the modified descendants of widely distinct 
beings. The form of a crystal is determined solely by the mo- 
leculai' forces, and it is not surprising that dissimilar substances 
should sometimes assume the same form ; but with organic be- 
ings 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 physical condi- 
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, 

2^ "Lectures on Man," Eng. translat., Schweineschadel," 1864, s. 104. With ro- 

1864, p. 4tS8. spect to cattle, see M. de Quatrefages, 

33 "Die Racen des Schweines," i860, s. " Unit^ de TEspfece Humaine," 1861, p. 119. 
^^ *'Vorstudien fiir Gescbichte, etc., 

a)-voi. 3 


should ever afterward converge so closely as to lead to a near 
ap[)roach to identity throughout their whole organization. In 
the case of the convergent races of pigs above refersed to, evi- 
dence of their descent from two primitive stocks is, according 
\o Von Nathusius, still plainly retained, in certain bones of 
iheir skulls. If the races of man had descended, as is supposed 
b/ some naturalists, from two or more species, which differed 
fro-m each other as much, or nearly as much, as does the orang 
l-Oi/i the gorilla, it can hardly be doubted that marked differ- 
jncfco in the structure of certain bones would still be discover- 
ible in man as he now exists. 

Although the existing races of man differ in many respects, 
as in color, hair, shape of skull, proportions of the body, etc., 
yet, if their whole structure be taken into consideration, they 
are found ^o resemble each other closely in a multitude of 
points. Maxiy of these are of so unimportant or of so singular 
a nature that It is extremely improbable that they should ha^ 
been independently acquired by aboriginally distinct species or 
races. The san<e 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 abo- 
rigines, Negroes, and Europeans are as different from each other 
in mind as any three races that can be named ; yet I was in- 
cessantly struck, while 4iving with trie Fuegians on board the 
Beagle, with the many little traits of character, showing how 
similar their minds were to ours ; and so it was with a full- 
blooacd negro with whora I happened once to be intimate. 

He whvj will read Mr. Tylor's and Sir J. Lubbock's interest- 
ing woiks^ can hardly fail to be deeply impressed with the 
close similarity between the men of all races in tastes, disposi- 
tions, and habits. This is shown by the pleasure which they 
all take in dancing, rude music, acting, painting, tattooing, and 
otherwise decorating then^selves ; in their mutual comprehension 
of gesture-language, by the same expression in their features, 
and by the same; inarticulate cries, when excited by the same 
emotions. I'his similarity, or rather identity, is striking, 
when contrasted with the different expressions and cries made 
by distinct species of mor.keys. There is good evidence that 
the art of shooting w^ th bows and arrows has not been handed 
down from any common progenitor of mankind ; yet, as West- 
s' Tylor's "Early History ^^f Mrr«kind," p. 54. Lubbock's "Prehistoric Time^^J^ 
iS£A ; with respect to gesture-lajj^uwj^e, see edit., 1869. 


ropp and Nilsson have remarked,^ the stone arrow-heads, 
brought from the most distant parts of the world, and manu- 
factured 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 archceologisfe^'' with respect to certain widely 
prevalent ornaments, such as zigzags, etc. ; and with respect 
to various simple beliefs and customs, such as the burying of the 
dead under megalithic structures. I remember observing in 
South America,'^ that there, as in so man ^ other parts of the 
world, men have generally chosen the summits of lofty hills to 
throw up piles of stones, either as a record of some remarkable 
event, or for burying their dead. 

Now when naturalists observe a close agreement in numerous 
small details of habits, tastes, and dispositions between two or 
more domestic races, or between nearly aUied natural forms, 
they use this fact as an argument that they are descended from 
a common progenitor who was thus endowed j and conse- 
quently 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 bod- 
ily structure and mental faculties (I do not here refer to sim- 
ilar 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 separ- 
ated by the sea, no doubt, preceded any great amount of di- 
vergence of character in the several races ; for otherwise we 
should sometimes meet with the same race in distinct conti- 
nents ; and this is never the case. Sir J. Lubbock, after com- 
paring the arts now practised by savages in all parts of the 
world, specifies those which man could not have known when 
he first wandered from his original birthplace; for if once 
i'earned they would never have been forgotten.*^ He thus shows 
that *' the spear, which is but a development of the knife- 
point, and the club, which is but a long hammer, are the only 

'• " On Analogous Forms of Implements," •' Jonrnal of Ethnological Soc," as given io 

in "Memoirs of Anthropolog. Soc.," by H. "Scientific Opinion.." June 2, 1869, p. 3. 
M. Westropp. "The Trimitive Inhabitants ^7 " journal of Researches : Voyage €# 

of Scandinavia," Eng. translat., edited by the Beagle." p. <6. 
Sir T. Lubbock, 1868, p. 104. aa " Prehistoric Times," 1869, p. 574, 

'• Westropp, "On Cromlechs," etc., 

^g6 THE DESCENT OF MAN. [/a»t L 

things left.** He admits, however, that the art of making fire 
probably had been already discovered, for it is common to all 
the races now existing, and was known to the ancient cave- 
inhabitants of Europe. Perhaps the art of making rude canoes 
or rafts was likewise known ; but as man existed at a remote 
epoch, when the land in many places stood at a very different 
level to what it does now, he would have been able, without 
the aid of canoes, to have spread widely. Sir J. Lubbock 
further remarks how improbable it is that our earliest ances- 
tors could have *' counted as high as ten, considering that so 
many races now in existence cannot get beyond four." Never- 
theless, at this early period, the intellectual and social faculties 
of man could hardly have been inferior in any extreme degree 
to those possessed at present by the lowest savages ; otherwise 
primeval man could not have been so eminently successful in 
the struggle for life, as proved by his early and wide diffusion. 

From the fundamental differences between certain languages, 
some philologists have inferred that when man first became 
widely diffused, he was not a speaking animal ; but it may be 
suspected that languages, far less perfect than any now spjken, 
aided by gestures, might have been used, and yet have left no 
traces on subsequent and more highly developed tongues. 
Without the use of some language, however imperfect, it ap- 
pears doubtful whether man's intellect could have risen to the 
standard implied hy his dominant position at an early period. 

Whether primeval man, when he possessed but iQ\s arts, and 
those of the rudest kind, and when his power of language was 
extremely imperfect, would have deserved to be called man, 
must depend on the definition which we employ. In a series 
of forms graduating insensibly from some ape-like creature to 
man as he now exists, it would be impossible to fix on any 
definite point when the term " man " ought to be used. But 
this is a matter of very little importance. So again, it is 
almost a matter of indifference whether the so-called races of 
man are thus designated, or are ranked asspecies or sub-species ; 
but the latter term appears the more appropriate. Finally, we 
may conclude that when the principle of evolution is generally 
accepted, as it surely will be before long, the dispute between 
the monogenists and polygenists v/ill die a silent and unob- 
served death. 

One other question ought not to be passed over without 
notice, namely, whether, as is sometimes assumed, each sub* 


species or race of man has sprung from a single pair of pro- 
genitors. With our domestic animals a new race can readily 
be formed by carefully matching the varying offspring from a 
single pair, or even from a single individual possessing some 
new character; but most of our races have been formed, not 
intentionally from a selected pair, but unconsciously by the 
preservation of many individuals which have varied, however 
slightly, in some useful or desired manner. If in one country 
stronger and heavier horses, and in another country lighter and 
fleeter ones, were habitually preferred, we may feel sure that 
two distinct sub-breeds would be 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, while those which have run wild on the 
Pampas have acquired larger and coarser heads ; and such 
changes are manifestly due, not to any one pair, but to all the 
individuals having been subjected to the same conditions, 
aided, perhaps, by the principle of reversion. The new sub- 
breeds in such cases are not descended from any single pair, but 
from many individuals which have varied in different degrees, 
but in the same general manner ; and we may conclude that the 
races of man have been similarly produced, the modifications 
being either the direct result of exposure to different conditions, 
or the indirect result of some form of selection. But to this 
latter subject we shall presently return. 

On the Extinction of the Races of Mail. — The partial or 
complete extinction of many races and sub-races of man is 
historically known. Humboldt saw in South America a parrot 
which was the sole living creature that could speak a word of 
the language of a lost tribe. Ancient monuments and stone 
implements found in all parts of the world, about which no 
tradition has been preserved by the present inhabitants, indi- 
cate much extinction. Some small and broken tribes, rem- 
nants 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 de- 
scribed by Prof. Broca from Les Eyzies, though they unfor- 

•• Translation in " Anthropological Review," October, 1868, p. 431. 

198 THE DESCENT OF MAN. [part \ 

tunately 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 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- 
favorable for his existence. ^^ He has long lived in the extreme 
regions of the North, with no wood for his canoes or imple- 
ments, and with only blubber as fuel, and melted snow as 
drink. In the southern extremity of America the Fuegians 
survive without the protection of clothes, or of any building 
worthy to be called a hovel. In South Africa the aborigines 
wander over arid plains, where dangerous beasts abound. Man 
can withstand the deadly influence of the Terai at the foot of 
the Himalaya, and the pestilential shores of tropical Africa. 

Extinction follows chiefly from the competition of tribe with 
tribe, and race with race. Various checks are always in ac- 
tion, 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, 
licentiousness, the stealing of women, infanticide, and espe- 
cially lessened fertility. If any one of these checks increases in 
power, even slightly, the tribe thus affected tends to decrease ; 
and when of two adjoining tribes one becomes less numerous 
and less powerful than the other, the contest is soon settled by 
war, slaughter, cannibalism, slavery, and absorption. Even 
when a weaker tribe is not thus abruptly swept away, if it 
once begins to decrease, it generally goes on decreasing until 
it becomes extinct.® 

When civilized nations come into contact with barbarians 
the struggle is short, except where a deadly climate gives its aid 
to the native race. Of the causes which lead to the victory of 
civilized nations, some are plain and simple, others complex 
and obscure. We can see that the cultivation of the land will 
be fatal in many ways to savages, for they cannot, or will not, 
change their habits. New diseases and vices have in some 
cases proved highly destructive ; and it appears that a new 
disease often causes much death, until those who are most 
susceptible to its destructive influence are gradually weeded 

30 ''Transact Internat (jongress of Pre- " Dr. Gerland "Ueber das Aussterbea 

historic Arch.," 1868, pp. 172-175. See also der Naturvolker." 1868, s. 8a. 

Broca (translation) in "Anthropological ^^ Gerland (ibid., s. 12) gives facts in slip* 

Review," October, 1868, p. 410. port of this statement. 


out;^ and so it may be with the evil effects from spirituous 
liquors, as well as with the unconquerably strong taste for them 
shown by so many savages. It further appears, mysterious as 
is the fact, that the first meeting of distinct and separated peo- 
ple generates disease.^ Mr. Sproat, who in Vancouver Island 
closely attended to the subject of extinction, believed that 
changed habits of life, consequent on the advent of 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 civilization seems to be a most important 
^lement 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 mod- 
xiXTi civilized 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 potent of all the causes of extinction appears in many 
cases to be lessened fertility and ill-health, especially among 
the children, arising from changed conditions of life, notwith- 
standing that the new conditions may not be injurious in them- 
selves. I am much indebted to Mr. H. H. Ho worth for hav- 
ing called my attention to this subject, and for having given 
mc inforniation respecting it. I have collected the following 

When Tasmania was first colonized the natives were roughly 
estimated by some at 7,000, and by others at 20,000. Their 
number was soon greatly reduced, chiefly by fighting with the 
Enghsh 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 individ- 
uals,^ who were in 1832 transported to Flinders Island. This 
island, situated between Tasmania and Australia, is forty miles 
long, and from twelve to eighteen miles broad : it seems 

"See temarks to this effect in Sir H. '* Sproat, " Scenes and Studies of Savage 

Holland's "Medical Notes and Reflections," Life," 1868, p. 284. 

1839, p. 3v)o. 38 Bagehot. "Physics and Politics," 

»* I have collected ("Journal of R©- "Fortnightly Review," April i, 1868, p. 

searches: Voyage of the Beagle," p. 435) 455. 

a good many cases bearing on this subject ; '^ All the statements here given are taken 

see also uclaud (ibid., s. 8). Poeppig from " The Last of the Tasmanians," by J. 

speaks of tl«e " breath of civilization as Bonwick, 1870. 
poisonous to e^ivages." 


healthy, and the natives were well treated. Nevertheless, they 
suffered greatly in healtli. In 1834 tlicy consisted (Bonwick, 
p. 250) of forty-seven adult males, forty-eight adult females, 
and sixteen children, or in all of iii souls. In 1^5 only one 
hundred were left. As they continued rapidly to decrease, 
and as they themselves thought that they should not perish so 
quickly elsewhere, they were removed in 1847 to Oyster Cove, 
in the southern part of Tasmania. They then consisted (Decem- 
ber 20, 1847) of fourteen men, twenty-two women, and ten chii 
dren.*^ But the change of site did no good. Disease and 
derth still pursued them, and in 1864 one man (who died in 
1869), and three elderly women alone survived. The infer- 
tility of the women is even a more remarkable fact than the 
liabihty of all to ill-health and death. At the time when only 
nine women were left at Oyster Cove, they told Mr. Bonwick 
(p. 386) that only two had ever borne children : and these 
two had together produced only three children ! 

With respect to the cause of this extraordinary state of things. 
Dr. Story remarks that death followed the attempts to civilize 
the natives. ** If left to themselves to roam as they were wont 
and undisturbed, they would have reared more children, and 
there would have been less mortality.'* Another careful oc- 
server 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 Die- 
men's Land, and consequent depression of spirits" (Bonwick, 
pp. 388, 390). 

Similar facts have been observed in two widely different 
parts of Australia. The celebrated explorer, Mr. Gregory, 
told Mr. Bonwick, that in Queensland ** the want of repro- 
duction was being already felt with the blacks, even in the 
most recently settled parts, and that decay would set in." Of 
thirteen aborigines from Shark's Bay who visited Murchison 
River, twelve died of consumption within three months.^ 

The decrease of the Maories of New Zealand has been care- 
fully investigated by Mr. Fenton, in an admirable Report, from 
which all the following statements, with one exception, are 
taken.^ The decrease in number since 1830 is admitted by 

•8 This is the statement of the Governor "The Last of the Tasmanians," 1870, p^ 

of Tasmania, Sir W. Denison, " Varieties of 386. 

Vice-Regal Life," 1870, vol. i. p. 67, ♦''"Observations on the Aboriginal In« 

-' For these cases, see Bonwick's " Daily habitants of New Zealand," published bf 

lafe of the Tasmanians," 1870, p. 90 ; and the Government, i859* ,.^ 


everyone, including the natives themselves, and is still steadily 
progressing. 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 yeais 
previous to 1858 the decrease was 19.42 per cent. Some of 
the tribes thus carefully examined lived above a hundred 
miles apart, some on the coast, some inland ; and their means 
of subsistence and habits differed to a certain extent (p. 28). 
The total number in 1858 was believed to be 53,700, and in 
1872, after a second interval of fourteen years, another census 
was taken, and the number is given as only 36,359, showing a 
decrease of 32.29 per cent. ! ^^ Mr. Fenton, after showing in 
detail the insufficiency of the various causes usually assigned 
in explanation of this extraordinary decrease, such as new 
diseases, the profligacy of the women, drunkenness, wars, etc., 
concludes on weighty grounds that it depends chiefly on the 
unproductiveness of the women, and on the extraordinary mor- 
tality of the young children (pp. 31, 34). In proof of this 
he shows (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 fcAver females are born than males. To this lat- 
ter point, depending perhaps on a widely distinct cause, I shall 
return in a future chapter. Mr. Fenton contrasts with aston- 
ishment the decrease in New Zealand with the increase in Ire- 
land — countries not very dissimilar in climate, and wkere the 
inhabitants now follow nearly similar habits. The Maories 
themselves (p. 35) '' attribute their decadence, in some meas- 
ure, to the introduction of new food and clothing, and the 
attendant change of habits ; ' ' and it will be seen, when we con- 
sider the influence of changed conditions on fertility, that they 
are probably right. The diminution began between the years 
1830 and 1840 ; and Mr. Fenton shows (p. 40) that about 1830 
the art of manufacturing putrid corn (maize), by long steeping 
in water, was discovered and largely practised ; and this proves 
that a change of habits was beginning among the natives 
even when New Zealand was only thinly inhabited by Euro- 
peans. 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^ 

«4 "New Zealand," by Alex. Kennedy, 1873, P* 4J'» - 



iPART i. 

and exchanged them for Enghsh manufactured goods and 

It is evident, from many statements in the hfe of Bishop 
Patteson,'^' that the Mclanesians of the New Hebrides and 
neighboring archipelagoes suffered to an extraordinary degree 
in health, and perished in large numbers, when they were 
removed to New Zealand, Norfolk Island, and other salubrious 
places, in order to be educated as missionaries. 

The decrease of the native population of the Sandwich 
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 1823, the 
numbers then were 142,050. In 1832, and at several subse- 
quent periods, an accurate census was officially taken, but I 
have been able to obtain only the following returns : 


Native Population. 

(Except during 1832 and 
1836, when the few for- 
eigners in the islands 
were included.) 

Annual rate of decrease per 
cent., assuming it to have 
been uniform between the 
successive censuses ; these 
censHses being taken at irreg- 
ular intervals. 

18^2 , 



7i»oi9 : 
67,084 1 



"^j** •••••••••••••••••• 

£8^6 ...,* 


181:^ .♦., 








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 labor 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 extraordi- 

«« ♦»iafc of J. C. Patteson," by C. M. Yonge, 1874 •, see more especially voL i. p. 530b 


nary rate of decrease between the years 1832 and 1836; but 
the most potent of all the causes seems to be lessened fertility. 
According to Dr. Ruschenberger of the U. S. Navy, who 
visited these islands between 1835 and 1837, in one district of 
Hawaii, only twenty-five men out of 1,134, and in another dis- 
trict only ten out of 637, had a family with as many as three 
children. Of eighty married women, only thirty-nine had 
ever borne children ; and ** the official report gives an average 
of half a child to each married couple in the whole 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, are rewarded by gifts of land and 
other encouragements." This unparalleled enactment by the 
government well shows how infertile the race had become. 
The Rev. A. Bishop stated in the Hawaiian Spectator, in 
1839, that a large proportion of the children die at early ages, 
and Bishop Staley informs me that this is still the case, just as 
in New Zealand. This has been attributed to the neglect of 
the children by the women, but it is probably in large part due 
to innate weakness of constitution in the children, in relation to 
the lessened fertility of their parents. There is, moreover, 
a further resemblance to the case of New Zealand, in the fact 
that there is a large excess of male over female births : the 
census of 1872 gives 31,650 males to 25,247 females of all 
ages, that is 125.36 males for every 100 females; whereas m 
all civilized countries the females exceed the males. No doubt 
the profligacy of the women may in part account for their small 
fertility ; but their changed 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 is- 
lands were visited by Cook in 1779, by Vancouver in 1794, 
and often subsequently by whalers. In 18 19 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 civihzed of the 
Pacific Islanders." One of my informants,- Mr. Coan, who 
was born on the islands, remarks that the natives have under- 
gone a greater change in their habits of life in the course of 
fifty years than Englishmen during a thousand years. From 
information received from Bishop Staley, it does not appear 
that the poorer classes have ever much changed their diet. 


although many new kinds of fruit have been introduced, and 
the sugar-cane is in universal use. Owing, however, to their 
passion for imitating Europeans, they altered their manner of 
dressing at an early period, and the use of alcoholic drinks 
became very general. Although these changes appear incon- 
siderable, I can well believe, from what is known with respect 
to animals, that they might suffice to lessen the fertility of the 

Lastly, Mr. Macnamara states '^^ that the low and degraded 
inhabitants of the Andaman Islands, on the eastern side of the 
Gulf of Bengal, are '' eminently susceptible to any change of 
climate ; in fact, take them away from their island homes, and 
they are almost certain to die, and that independently of diet 
or extraneous influences." He further states that the inhabi- 
tants 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 m 
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 civilized races. Man in 
his wild condition seems to be in this respect almost as suscep- 
tible 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, Maori es. 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 

*• The foregoing statements are taken several years to the kindness of Mr. Coan, 

chiefly from the following works : " Jarves's at the request of Dr. Youmans, of New York; 

History of the Hawaiian Islands," 1843, pp. and in most cases I have compared the 

400-407. Cheever, " Life in the Sandwich Youmans figures with those given in several 

islands," 1851, p. 277. Ruschenberger is of the above-named works. I have omitted 

quoted by Bonwick, "Last of the Tasma- the census for 1850. as I have seen two 

plans," 1870, p. 378. Bishop is quoted by widely different numbers given. 

Sir E. Belcher, "Voyage Round the World," ""The Indian Medical Gazette," N«- 

1843, vd. i. p. 373. I owe the census of the vember i, 1671, p. 240. 


extinction. The diminution of fertility may be explained in 
some cases by the profligacy of the women (as until lately with 
the Tahitians), but Mr. Fenton has shown that this explana- 
tion by no means suffices with the New Zealanders, nor does it 
with the Tasmanians. 

In the paper above quoted, Mr. Macnamara gives reasons for 
b<eiieving that the inhabitants of districts subject to malaria are 
apt to be sterile ; but this cannot apply in several of the above 
cases. Some writers have suggested that the aborigines of 
islands have suffered in fertility and health from long-continued 
interbreeding ; but in the above cases infertihty 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 interbreeding, 
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 fertihty.'*^ 

A much more probable view is suggested by the analogy of 
the lower animals. The reproductive system can be shown to 
be susceptible to an extraordinary degree (though why we 
know not) to changed conditions of life ; and this susceptibil- 
ity leads both to beneficial and to evil results. A large col- 
lection of facts on this subject is given in chapter xviii. of 
volume ii. of my ''Variation of Animals and Plants under 
Domestication," I can here give only the briefest abstract ; and 
everyone interested in the subject may consult the above work. 
Very slight changes increase the health, vigor, and fertility of 
most or all organic beings, while other changes are known tc 
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 instance, because of their rela- 
tionship to man. It is remarkable how slight a change in the 

** On the dose relationship of the Norfolk 1873, p. no. For the Western Islands ol 

Ishiik-rs, see Sir W. Denison, "Varieties Scotland, Dr. Mitchell, "Edinburgh Med^ 

oi \;i;.-Rog;il I.ife," vol. i., iSyo, p. 410, cai Journal, ' March to June, 1865. 
For ths Todas, see Colonel Marshall's work. 

206 THE DESCENT OF MAN". [part t 

conditions often induces sterility in a wild animal when capt- 
ured ; 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 condi- 
tions 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 group 
is rendered sterile, while the others are not so ; on the other 
hand, a single species may retain its fertility while most of the 
others fail to breed. The males and females of some species 
when confined, or when allowed to live almost, but not quite 
free, in their native country, never unite ; others thus circum- 
stanced frequently unite but never produce offspring; others 
again produce some offspring, but fewer than in a state of nat- 
ure ; and, as bearing on the above cases of man, it is impor- 
tant to remark that the young are apt to be weak and sickly, 
or malformed, and to perish at an early age. 

Seeing how general is this law of the susceptibility of the 
reproductive system to changed conditions of life, and that it 
holds good with our nearest allies, the Quadrumana, I can 
hardly doubt that it applies to man in his primeval state. 
Hence if savages of any race are induced suddenly to change 
their habits of life, they become more or less sterile, and their 
young offspring suffer in health in the same manner and from 
the same cause as do the elephant and hunting-leopard in 
India, many monkeys in America, and a host of animals of all 
kinds, on removal from their natural conditions. 

We can see why it is that aborigines, who have long in- 
habited islands, and who must have been long exposed to 
nearly uniform conditions, should be specially affected by any 
change in their habits, as seems to be the case. Civilized races 
can certainly resist changes of all kinds far better than savages ; 
and in this respect they resemble domesticated animals, for 
though the latter sometimes suffer in health (for instance, Euro- 
pean dogs in India), yet they are rarely rendered sterile, 
though a few such instances have been recorded. ^^ The im- 
munity of civilized races and domesticated animals is probably 
due to their having been subjected to a greater extent, and 
therefore having grown somewhat more accustomed, to diversi- 
fied or varying conditions, than the majority of wild animals ; 

** For the evidence on this head, see '•t •• Variation of Animalst" etc.* voL lib 
.**Variaooo of Animals," etc., voL ii. p. \i.\. p. x6i 


and to their having formerly immigrated or been carried from 
country to country, and to different families or sub races hav- 
ing intercrossed. It appears that a cross with civilized races 
at once gives to an aboriginal race an immunity from the evil 
consequences of changed condition=^. Thus the crossed off- 
spring from the Tahitians and English, when settled in Pitcaim 
Island, increased so rapidly that the island was soon over- 
stocked; and in June, 1856, they were removed to Norfolk 
Island. They then consisted of 60 married persons and 134 
children, making a total of 194. Here they likewise increased 
so rapidly that, although sixteen of them returned to Pitcairn 
Island in 1859, they numbered in January, 1868, 300 souls — the 
males and females being in exactly equal numbers. What a con- 
trast does this case present with that of the Tasmanians; the Nor- 
folk Islanders ?>/<rr^^^^^ in only twelve and a half years from 194 
to 300; whereas the Tasmanians ^-f^r^^^y^-^/ during fifteen years 
from 120 to 46, of which latter number only ten were children.^ 
So again in the interval between the census of 1866 and 1872 
the natives of full blood in the Sandwich Islands decreased by 
8,081, while the half castes, who are believed to be healthier, in- 
creased by 847; but I do not know whether the latter number 
includes the offspring from the half-castes, or only the half-castes 
of the first generation. 

The cases which I have here given all relate to aborigines who 
have been subjected to new conditions as the result of the immi- 
gration of civilized men. But sterility and ill-health would 
probably follow, if savages were compelled by any cause, such 
as the inroad of a conquering tribe, to desert their homes and to 
change their habits. It is an interesting circumstance that the 
chief check to wild animals becoming domesticated, which im- 
plies the power of their breeding freely when first captured, and 
one chief check to wild men, when brought into contact with 
civilization, surviving to form a civilized race, is the same, 
namely, sterility from changed conditions of life. 

Finally, although the gradual decrease and ultimate extinc- 
tion of the races ot man is a highly complex problem, depend- 
ing on many causes which differ in different places and at dif- 
ferent times; it is the same problem as that presented by the 
extinction of one of the higher animals — of the fossil horse, for 

*8 These details are taken from "The Commons, May 79, 1863. The following 
Mutineers of the Bounty," by Lady Bel- statements about the Sandwich Islanders 
clier, 1870; and from "Pitcairn Island," are from the "Honolulu Gazette," and 
ordered to be printed by the House of from Mr. Coan. 

208 THE DESCENT OF MAN". [part L 

instance, which disappeared from South America, soon after- 
ward to be replaced, witliin tlie same districts, by coiinuess 
troops of the Spanish horse. 'I'he New Zealander seems con- 
scious of this parallelism, for he compares his future fate with 
that of the native rat now almost exterminated by the European 
rat. Though the difficulty is great to our imagination, and 
really great, if we wish to ascertain the precise causes and their 
manner of action, it ought not to be so to our reason, as long 
as we keep steadily in mind that the increase of each species 
and each race is constantly checked in various ways ; so that if 
any new check, even a slight one, be superadded, the race will 
surely decrease in number; and decreasing numbers will sooner 
or later lead to extinction ; the end, in most cases, being 
promptly determined by the inroads of conquering tribes. 

O71 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, while Europeans differ but 
little from Jews, who belong to the Semitic stock, and speak 
quite another language, has been accounted for by Broca,^^ 
through certain Aryan branches 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 San tali or hill- 
tribes of India, says that hundreds of imperceptible gradations 
may be traced " from the black, squat tribes of the mountains 
to the tall, olive-colored 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 San^ 
talis or Hindoos.^ Whether a heterogeneous people, such as 
the inhabitants of some of the Polynesian islands, formed by 
the crossing of two distinct races, with few or no pure mem- 
bers left, would ever become homogeneous, is not known from 
direct evidence. But as with our domesticated animals, a 
cross-breed can certainly be fixed and made uniform by care- 
ful 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 

«» "On Anthropology," translation, "An- ^*- " The Variation of Animals and Plant* 
thropolog. Review," Jan., 1868, p. 38. i»der Domestication," voL iL p. 95. 

*» "Annals of Rural Bengal," 1868, p. 134. 


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 color of 
the skin is the most conspicuous and one of the best marked. 
It was formerly thought that differences of this kind could be 
accounted for by long exposure to different climates ; but PaUas 
first showed that this is not tenable, and he has since been t<?l- 
lowed by almost all anthropologists.^'^ This view has been re- 
jected chiefly because the distribution of the variously colored 
races, most of whom must have long inhabited their present 
homes, does not coincide with corresponding differences of 
climate. Some little weight may be given to such cases as that 
of the Dutch families, who, as we hear on excellent author- 
ity,^^ have not undergone the least change of color after resid- 
ing for three centuries in South Africa. An argument on the 
same side may likewise be drawn from the uniform appearance 
in various parts of the world of gypsies and Jews, though the 
uniformity of the latter has been somewhat exaggerated.^ A 
very damp or a very dry atmosphere has been supposed to be 
more influential in modifying the color of the skin than mere 
heat ; but as D'Orbigny in South America, and Livingstone in 
Africa, arrived at diametrically opposite conclusions with re- 
spect 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 
color of tne skin and hair is sometimes correlated in a surpris- 
ing manner with a complete immunity from the action of cer- 
tain vegetable poisons, and from the attacks of certain parasites. 
Hence it occurred to me, that negroes and other dark races 
might have acquired their dark tints by the darker individuals 
escaping from the deadly influence of the miasma of their 
native countries, during a long series of generations. 

I afterward found that this same idea had long ago occurred 
to Dr. Wells. ^'^ It has long been known that negroes, and even 
mulattoos, are almost completely exempt from the yellow fever, 

" Pallas, "Act. Acad. St. Petersburg," in S. Africa," 1857, pp. 338, 329. D'Or- 

1780, part ii. p. 69. He was followed by bigny, as quoted by Godron, " Del' Espece," 

Rudolphi, in his " Beytrage zur Anthropolo- vol. li. p. 266. 

gie," 1812. An excellent summary of the '* See a paper read before the Royal Soc. 

evidence is given by Godron, " De l'Esp6ce," in 1813, and published in his Essays in 1818. 

1859, vol. ii. p. 246, etc. I have given an account of Dr. Wells's views 

^* Sir Andrew Smith, as quoted by Knox, in the Historical Sketch (p. xvi.) to my 

*' Races of Man," 1850, p. 473. " Origin of Species." Various cases of color 

^^ See De (^uatrefiiges on this head, correlated with constitutional peculi.-^rities 

" Revue des Cours Scientifiques," Oct. 17, arc given in my "Variation of Animals un- 

1868, p. 731. der Domestication," vol. ii. pp. 227, 335, 

•• Livingstone's " Travels and Researches 

210 THE DESCENT OF MAN. [part f. 

SO destructive in tropical America.''^ They likewise escape to 
a large extent tlie fatal intermittent fevers that jjrevail along 
at least 2,600 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 jieculiarity 
of constitution, and partly the result of acclimatization. Pou- 
chet^^ 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 origi- 
nally brought from various parts of Africa and accustomed to 
the climate of the West Indies. That acclimatization plays a 
part, is shown by the many cases in which negroes have be- 
come somewhat liable to tropical fevers after having resided 
for some time in a colder climate.^ The nature of the climate 
under which the white races have long resided likewise has 
some influence on them ; for 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 lati- 
tude of the country whence they had come. With the negro 
the immunity, as far as it is the result of acclimatization, im- 
plies exposure during a prodigious length of time ; for the abo- 
rigines of tropical America who have resided there from time 
immemorial are not exempt from yellow fever ; and the Rev. 
H. B. Tristram states that there are districts in Northern 
Africa which the native inhabitants are compelled annually to 
leave, though the negroes can remain with safety. 

That the immunity of the negro is in any degree correlated 
with the color of his skin is a mere conjecture : it may be cor- 
related with some difference in his blood, nervous system, or 
other tissues. Nevertheless, from the facts above alluded vo, 
and from some connection apparently existing between com- 
plexion and a tendency to consumption, the conjecture seemed 
to me not improbable. Consequently I endeavored, with but 
little success,^^ to ascertain how far it holds good. The late 

" See, for instance, Nott and GHddon, ^' In the spring of 1862 I obtained per- 

*' Types of Mankind," p. 68. mission from the Director-General of the 

'8 Major Tulloch, in a paper read before Medical Department of the Army to trans- 

the Statistical Society, April 20, 1840, and mit to the surgeons of tlie various regiments 

given in the "'Athenaeum," 1840, p. 353. on foreign service a blank table, with the fol- 

*' "The Plurality of the Human Race" lowing appended remarks, but I have re- 

(translat.), 1864, p. 60. ceived no rtturns. "As several well-marked 

"• Quatrefages, " Unite de I'Espfece Hu- cases have been recorded with our domestic 

maine," 1861, p. 205. Waitz, " Introduct. animals of a relation between the color of 

to Anthropology," translat., vol. i., 1863, p. the dermal appendages and the constitution, 

I&4. Liringstone gives analogous cases in and it being notorious thai there is some 

his *' Travels." limited degree of relation between the colQi' 


Dr. Daniell, who had long hved on the West Coast of Africa, 
told me that he did not believe in any such relation. He was 
himself unusually fair, and had withstood the climate in a 
wonderful manner. When he first arrived as a boy on the 
coast, an old and experienced negro chief predicted from his 
appearance that this would prove the case. Dr. Nicholson, of 
Antigua, after having attended to this subject, writes to me 
that he does not think that dark-colored Europeans escape the 
yellow fever more than those that are light-colored. Mr. J. 
M. Harris altogether denies that Europeans with dark hair 
withstand a hot climate better than other men : on the con- 
trary, experience has 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 re- 
sulted 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 chil- 
dren only six or eight months old are often carried about naked, 
and are not affected. I have been assured by a medical man 
that some years ago during each summer, but not during the 
winter, his hands became marked with light brown patches, 
like, although larger than freckles, and that these patches were 
never affected by sun-burning, while the white pari-^ of his 

of liie races of man and the climate in- high interest, as indicating one means by 
habited by them, the following investiga- which a race of men inhabiting from a re« 
tion seems worth consideration : Namely, mote period an unhealthy tropical climate, 
whether there is any relation in Europeans might have become dark-colored by the 
between the color of their hair and their better preservation of dark-haired or dark- 
liability to the diseases of tropical countries, complexioned individuals during a long suc- 
If the surgeons of the several regiments, cession of generations." 

when stationed in unhealthy tropical liis- ^^ "Anthropological Review," Jan., 1866, 

tricts, would be so good as first to count, as p. xxi. Dr. Sharpe also .says, with respect 

a standard of comparison, how many men, to India (" Man a Special Creation," 1873, 

in the force whence the sick are drawn, have p. 118), that " it has been noticed by some 

dark and light-colored hair, and hair of in- medical officers that Europeans with light 

termediate or doubtful tints ; and if a simi- hair .ind florid complexions suffer less from 

lar account were kept by the same medical diseases of tropical countries than persons 

gentlemen, of all the men who suffered from with dark hair and .sallow complexions ; 

malarious Pud yellow fevers, or from dysen- and, so far as I know, there appear to be 

tery, it would soon be apparent, after some good grounds for this rem.'irk." On the 

thousand cases had been tabulated, whether other hand, Mr. Heddle, of Sierra Leone, 

there exists any relation between the color of " who has had more clerks killed under him 

the hair and constitutional liability to tropi- than any other man," by the climate of the 

cal diseases. Perhaps no such relation would West African Coast (W. Reade, " African 

t)e discovered, but the investigation is well Sketch Book," vol. ii. p. S22), holds a di- 

worth making. In case any positive results rectly opposite view, as does Capt. Burton, 
were obtained, it might be o' some practical ^^ " Man a Special Creation," 1873, p, 

use in selecting men for anj particular ser- 119. 
vice. Theoretically the result would be of 

212 THE DESCENT OE MAN". (part 1. 

skin have on several occasions been much inflamed and bhs- 
tered. With the lower animals there is, also, a constitutional 
difference in liability to the action of the snn between those 
parts of the skin clothed with white hair and other parts. ^ 
Whether the saving of the skin from being thus burned is of suf- 
ficient importance to account for a dark tint having been grad- 
ually acquired by man through natural selection, 1 am unable 
to judge. If it be so, we should have to assume that the 
natives of tropical America have lived there for a much shorter 
time than the negroes in Africa, or the Papuans in the south- 
ern parts of the Malay archipelago, just as the lighter-colored 
Hindoos have resided in India for a shorter time than the 
darker aborigines of the central and southern parts of the pen- 

Although with our present knowledge we cannot account for 
the differences of color in the races of man, through any ad- 
vantage 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 gen« 
erally admitted, the European settlers in the United States un- 
dergo 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 ap- 
pearance presented by the German regiments, when dressed in 
ready^made clothes manufactured for the American market, 
and which were much too long for the men in every way. 
There is, also, a considerable body of evidence showing that 
in the Southern States the house-slaves of the third generation 
present a markedly different appearance from the field-slaves.^ 

If, however, we look to the races of man as distributed over 
the world, we must infer that their characteristic differences 
cannot be accounted for by the direct action ©f different con~ 

"* " Variation of Animals and Plants un- quired in the course of two generations dark 

der Domestication," vol. ii. pp. 336, 337. hair and eyes. Mr. D. Forbes informs me 

*' See, for instance, Quatrefages (" Revue that the Quichuas in the Andes vary greatly 

des Cours Scientifiques," Oct. 10, 1868, p. in color, according to the position of the val- 

724) on the effects of residence in Abyssinia leys inhabited by them. 

and Arabia, and other analogous cases. Dr. ^' Harlan, *' Medical Researches," p. 532. 

RoUe (" Der Mensch, seine Abstammung," Quatrefages ("Unite del'Esp^cenumaine,* 

etc., 1865, s. 99) states, on the authority of 1861, p. 128) has collected much evidence 

Khanikof, that the greater number of Ger- on this bead, 
loan fanulies settled in Georgia have ac* 


ditions of life, even after exposure to them for an enormous 
period of timo. The Esquimaux hve 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 productions 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 Boto- 
cudos 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 habit- 
ually live in canoes may have their legs somewhat stunted ; 
those who inhabit lofty regions may have their chests enlarged ; 
and those who constantly use certain sense-organs may have the 
cavities in which they are lodged somewhat increased in size, 
and their features consequently a little modified. With civilized 
nations, the reduced size of the jaws from lessened use — the 
habitual play of different muscles serving to express different 
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 previously 
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 color of the skin and hair are plainly correlated, 
as is the texture of the hair with its color in the Mandans of 
North America.^ The color also of the skin, and the odor 

*' See Prof. Schaaff hausen, translat. in in ten or twelve of the members, of all ages 

"Anthropological Review," Oct., 1868, p. and both sexes, have bright silvery gray 

429. ^ hair, which is hereditary. Now this hair is 

'•'' Mr. Catlin states ("N. American In- as coarse and harsh as that of a horsar 

dians," 3d edit., 1842, vol. i. p. f,c,^ that in mane, while the hair of other colors is tine 

2be whole tribe of the Mandans, about one and soft. 


emitted by it, are likewise in some manner connected. With 
the breeds of sheep the number of hairs within a given space 
and tile number of the excretory pores are related.^ If we 
may judge from the analogy of our domesticated animals, many 
modifications of structure in man probably come under this 
principle of correlated development. 

We have now seen tbpt 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 
infportance ; for, if important, they would long ago have been 
either fixed and preserved, or eHminated. In this respect 
man resembles those forms, called by naturalists protean or 
polymorphic, which have remained extremely variable, owing, 
as it seems, to such variations being of an indifferent nature, 
and to their having thus escaped the action of natural selec- 

We have thus far been baffled in all our attempts to account 
for the differences between the races of man ; Dut there re- 
mains 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 unex« 
plained residuum is left, about which we can only say, in our 
ignorance, that as individuals 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 unknown agencies which induced 

•» On the odor of the skin, Godron, " Sur the skin, Dr. Wilckens, "DieAu^gabcndCt 
f Esp^" too. iL p, 317. Oa the pores in Landwirth. Zootecbnik," i860, 8. 7* _ 


them were to act in a more constant manner, aided by long- 
continued intercrossing. Such variations come under the pro- 
visional class alluded to in our second chapter, which for the 
want of a better term are often called spontaneous. Nor do I 
pretend that the effects of sexual selection can be indicated with 
scientific precision; but it can be shown that it would be an 
inexplicable fact if man had not been modified by this agency, 
which appears to have acted powerfully on innumerable ani- 
mals. It can further be shown that the differences between the 
races of man, as in color, hairiness, form of features, etc., are 
of a kind which might have been expected to come under 
the influence of sexual selection. But in order to treat this 
subject properly, I have found it necessary to pass the whole 
animal kingdom in review. I have therefore devoted to it the 
Second Part of this work. At the close I shall return to man, 
and, after attempting to show how far he has been modified 
through sexual selection, will give a brief summary of the 
chapters in this First Part. 

Note on the Resemblances and Differences in the Structure 
AND the Development of the Brain in Man and Apes. By 
Prof. Huxley, F.R.S. 

The controversy respecting the nature and the extent of the differences 
in the structure of the brain in man and the apes, which arose some fifteen 
years ago, has not yet come to an end, though the subject-matter of the dis- 
pute is, at present, totally different from what it was formerly. It was 
originally asserted and reasserted, with singular pertinacity, that the brain 
of all the apes, even the highest, differs from that of man, in the absence 
of such conspicuous structures as the posterior lobes of the cerebral hemi- 
spheres, with the posterior cornu of the lateral ventricle and the hif>po- 
campus minor, contained in those lobes, which are so obvious in man. 

But the truth that the three structures in question are as well developed 
in apes' as in human brains, or even better ; and that it is characteristic of 
all the Primates (if we exclude the Lemurs) to have these parts well de- 
veloped, stands at present on as secure a basis as any proposition in com- 
parative anatomy. Moreover, it is admitted by every one of the long series 
of anatomists who, of late years, have paid special attention to the arrange- 
ment of the complicated sulci and gyri which appear upon the surface of 
the cerebral hemispheres in man and the higher apes, that they are dis- 
posed after the very same pattern in him, as in them. Every principal 
gyrus and sulcus of a chimpanzee's brain is clearly represented in that of 
a man, so that the terminology which applies to the one answers for the 
other. On this point there is no difference of opinion. Some years since. 
Prof. Bischoff published a memoir ''° on the cerebral convolutions of man 

'" " Die Grosshim-Windungen dcs Menschen ;" "Abhandlungen der K. Bayerisphea 
Akademie," Bd. x., 1868. 

2l6 TffE DESCENT OE MAN. tPART l«.i 

and apes ; and as the purpose of my learned colleague was certainly not 
to diminish the value of the differences l)ftwccn 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 oiganization, much nearer than to any other 
animal, is a well-known fact, disputed by nobody. Looking at the mat- 
ter from the point of view of organization alone, no one probably would 
ever have disputed the view of Linnajus, that man should be placed, 
merely as a peculiar species, at the head of the mammalia and of those 
apes. Both show, in all their organs, so close an affinity, that the most 
'^xact anatomical investigation is needed in order to demonstrate those 
differences which really exist. So it is with the brains. The brains of 
man, the orang, the chimpanzee, the gorilla, in spite of all the important 
differences which they present, come very close to one another" (1. c, p. 

There remains, then, no dispute as to the resemblance, in fundamental 
characters, between the ape's brain and man's ; nor any as to the wonder- 
fully close similarity between the chimpanzee, orang, and man, in even the 
details of the arrangement of thegyri 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 symmetri- 
cally disposed, and present a greater number of secondary plications. 
And it is admitted that, as a rule, in man the temporo-occipilal or 
" external perpendicular " fissure, which is usually so strongly marked a 
feature of the ape's l^rain, is but faintly marked. But it is also clear 
that none of these differences constitute a sharp demarcation between 
the man's and the ape's brain. In respect to the external perpendic- 
ular fissure of Gratiolet, in the human brain, lor instance. Prof. 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 outward. I saw it in the right hemisphere of a female brain 
pass more than two inches outward ; and in another specimen, also the 
right hemisphere, it proceeded for four-tenths of an inch outward, and 
tlien extended downward as far as the lower margin of the outer surface of 
the hemisphere. The imperfect definition of this fissure in the majority 
of human brains, as compared with its remarkable distinctness in the brain 
of most 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 o^ 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, there- 
fore, 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 obliteration of the ex- 
ternal perpendicular sulcus by "bridging convolutions," on one side or the 
Other, has been noted over and over again by Prof. Rolleston, Mr, Mar- 

''^ "Convolutions of the Hvuxian Cerebrum Topographically Considered," 1866, p» li#/ 


shall, M. Broca, and Prof, Turner. At the conclusion of a special paper 
on this subject the latter writes : " 

"The three specimens of the brain of a chimpanzee just described, 
prove that the generalization which Gratiolet has attempted to draw of 
the complete absence of the first connecting convolution and the conceal- 
ment of the second, as essentially characteristic features in the brain of 
this animal, is by no means universally applicable. In only one specimen 
did the brain, in these particulars, follow the law which Gratiolet has 
expressed. As regards the presence of the superior bridging convolution, 
I am inclined to think that it has existed in one hemisphere, at least, in g 
majority of the brains of this animal which have, up to this time, been 
figured or described. The superficial position of the second bridging con- 
volution is evidently less frequent, and has as yet, I believe, only been seen 
in the brain (A) recorded in this communication. The asymmetrical ar- 
rangement in the convolutions of the two hemispheres, v/hich previous ob- 
servers 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 perpen- 
dicular, sulcus a mark of distinction between the higher apes and man, 
the value of such a distinctive character would be rendered very doubtful 
by the structure of the brain in the Platyrhine apes. In fact, while the 
temporo-occipital is one of the most constant of sulci in the Catarrhine or 
Old World apes, it is never very strongly developed in the New World 
apes ; it is absent in the smaller Platyrhini ; rudimentary in Pithecia ; '* 
and more or less obliterated by bridging convolutions in A teles. 

A character which is thus variable within the limits of a single group can 
have no great taxonomic value. 

It is further established that the degree of asymmetry of the convo- 
lution of the two sides in the human brain is subject to much individual 
variation ; and that, in those individuals of the Bushman race who have 
been examined, the gyri and sulci of the two hemispheres are considerably 
less complicated and more symmetrical than in the European brain, while 
in some individuals of the chimpanzee their complexity and asymmetry be- 
come notable. This is particularly the case in the brain of a young male 
chimpanzee figured by M. Broca, ("L'Ordre des Primates," p. 165, fig. 11.) 

Again, as respects the question of absolute size, it is established that 
the difference between the largest and the smallest healthy human brain 
is greater than the difference between the smallest healthy human brain 
and the largest chimpanzee's or orang's brain. 

Moreover, there is one circumstance in which the orang's and chim- 
panzee's brains resemble man's, but in which they differ from the lower 
apes, and that is the presence of two corpora candicantia — the Cy7ioinorpha 
having but one. 

In view of these facts I do not hesitate in this year 1874 to repeat and 
insist upon the proposition which I enunciated in 1863 : '* 

" So far as cerebral structure goes, therefore, it is clear that man differs 
less from the chimpanzee or the orang than these do even from the mon- 
keys, and that the difference between the brain of the chimpanzee and of 
man is almost insignificant, when compared with that between the chim- 
panzee brain and that of a Lemur." 

'* Notes more especially on the bridg^ing '^ Flower "On the Anatomy of Pithecia 

convolutions in the I^rain of the Chimpan- TI/t^wac/^KJ," " Proceedings of the Zoological 

zee, " Proceedings of the Royal Society of Society," 1862. 

Bdinburgh," 1865-6. '* " Man's Place in Nature," p. 102. 

(J)— VoL 3 


In the paper to wliich I liave referred, Prof. Bischoff does not deny 
the second part of this statement, but he first makes the irrelevant remark 
that it is not wonderful if the l^rains of an orang and a Lemur are very 
diflerent ; and secondly, goes on to assert that, " If we successively com- 
pare the brain of a man with that of an orang ; the brain of this with that 
of a chimpanzee ; of this with that of a gorilla, and so on of a //ylobates, 
Senuiopithectis^ Cynocephaliis^ Cercopithecus^ Macacus, Cebus^ Callithrix^ 
Lemur, S/c'/rops, jlap^ih\ we shall not meet with a greater, or even as 
great a, break in the degree of development of the convolutions, as we 
find between the brain of a man and that of an orang or chimpanzee." 

To which I reply, firstly, that whether this assertion be true or false, 
it has nothing whatever to do with the proposition enunciated in- " Man's 
Place in Nature," which refers not to the developnrent of the convolu- 
tions alone, but to the structure of the whole brain. If Prof. 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 knowledge 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 zxv^ hippocampus 
minor, more 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 pos- 
sesses a large posterior cornu with a well-developed hippocampus minor." 

This statement was a strictly accurate account of what was known when 
it was made ; and it does not appear to me to be more than apparently 
weakened by the subsequent discovery of the relatively small develop- 
ment 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, ap- 
proach those of the Lemurs. And if, instead of putting Hapale out of its 
natural place, as Prof. Bischoff most unaccountably does, we write the series 
of animals he has chosen to mention as follows : Homo, Fithecus, Trog- 
lodytes, Hylobates, Semnopitheciis^ Cynocephahis, Cercopithecus, Macacus, 
Cebi'.s, Callithrix, Hapale, Lemur, Stenops, I venture to reaffirm that the 
great break in this series lies between Hapale and Lemur, and that this 
break is considerably greater than that between any other two terms of that 
series. Prof. Bischoff ignores the fact that long before he wrote, Gratiolet 
had suggested the separation of the Lemurs from the other Frimates on 
the very ground of the difference in their cerebral characters ; and that 
Prof. Flower had made the following observations in the course of his de- 
scription of the brain of the Javan Loris : ""^ 

'*And it is especially remarkable that, in the development of the pos- 
terior lobes, there is no approximation to the Lemurine, short-hemisphered 
brain, in those monkeys which are commonly supposed to approach this 
family in other respects, viz., the lower members of the Platyrhine group." 

So far as the structure of the adult brain is concerned, then, the very 
considerable additions to our knowledge, which have been made by the 
researches of so many investigators, during the past ten years, fully justify 

« •• Transactions of the Zoological Society," vol. v., x863. 


the statement which I made in 1863. But it has been said that, admitting 
the similarity between the adult brains of man and apes, they are never- 
theless, in reality, widely different, because they exhil^it fundamental dif- 
ferences in the mode of their development. No one would be more ready 
than I to admit the force of this argument, if such fundamental differences 
of development really exist. Hut I deny that they do exist. On the con- 
trary, there is a fundamental agreement in the development of the brain 
in men and apes. 

Gratiolet originated the statement that there is a fundamental difference 
in the development of the brains of apes and that of man — consisting in 
this ; that, in the apes, the sulci which first make their appearance are 
situated on the posterior region of the cerebral hemispheres, while, in the 
human foetus, the sulci first become visible on the frontal lobes."'^ 

This general statement is based upon two observations, the one of a 
Gibbon almost ready to 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 22d or 23d week of 
utero-gestation, in which Gratiolet notes that the insula was uncovered, but 
that, nevertheless, " des incisures sement le lobe anterieur ; une scissure peu 
profonde indique la separation du lobe occipital, tres-reduit d'ailleurs d6s 
cette epoque. Le reste de la surface cerebrale est encore absolument lisse.'' 

Three views of this brain are given in Plate II., figs, i, 2, 3, of the work 
cited, showing the upper, lateral, and inferior views of the hemispheres, 
but not the inner view. It is worthy of note that the figure by no means 
bears out Gratiolet's description, inasmuch as the fissure (antero-temporal; 
on the posterior half of the face of the 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 cer- 
veaux [those of a Callithrix and of a Gibbon] et celui du foetus humain 
une difference fondamentale. Chez celui-ci, longtemps avant que les plis 
temporaux apparaissent, les plis frontaux essayent d'exister,'' 

Since Gratiolet's time, however, the development of the gyri and sulci of 
the brain has been made the subject of renewed investigation by Schmidt, 
Bischoff, Pansch,'^ and more particularly by Ecker,''^ whose work is not 
only the latest, but by far the most complete, memoir on the subject. 

''^ "Chez tousles singes, les plis postd- 32), writes thus: "Gratiolet a eu entre les 

rieurs se developpent les premiers; les plis mains le cerveau d'un foetus de Gibbon, 

anterieurs se developpent plus tard, aussi la singe ^niinemment superieur, et tellenient 

vert^bre occipitale et la parietale sont-elles rapproche de I'orang, que des naturalistes 

relativement tr^s-grandes chez le ftetus. tr^s competents I'ont rang^ parmi les an- 

L'Homme presente une exception remarqua- thropoides. M. Huxley, par exeinple, 

ble quant i I'^poque de I'apparitioii des plis n'hesite pas sur ce point. Eh bien, c'est 

frontaux, qui sont les premiers iudiqu^s ; sur le cerveau d'un foetus de Gil)bon que 

mais le ddveloppement general du lobe fron- Gratiolet a vu les cir convolutions du lobe 

tal. envisage seulement par rapport i son te>nporo-splihtoidal dejk de7it'loy>/>ec's lors- 

volunie, suit les memes lois que dans les quHl fi'existe pa<; encore de f>lis sur U 

singes." Gratiolet. '' Memoire sur les plis lobe frontal. II etait done bien autorise ^ 

cerebraux de I'Homme et des Primates," p. dire que, chez I'homme les circonvolutions 

39, tab. iv. fig. 3. apparaissent d'a en a», tandis que chez les 

^^ Gratiolet's words are (1. c, p. 39): singes elles se developpent d'w en a." 

"Dans le fetus dont il s'agit les plis c^r^- '» " Ueber die typische Anordnung der 

braux posterieurs sont bien developpes, tan- Furchen und Windungen auf den Grosshirn- 

dis que les plis du lobe frontal sont i peine in- Hemispharen des Menschen und der Affen." 

diqu^s." The figure, however (PI. iv. fig. 3), " Archiv fiir Anthropoiogie," iii., 1868. 

shows the fissure of Rolando, and one of ■"* " Zur Entwickelungs Geschichte der 

the frontal sulci, plainly enough. Neverthe- Furchen und Windimgen der Grosshim- 

lesR, M. Alix, in his " Notice sur les travaux Hemispharen im Foetus des Menschea. 

anthropologiques de CJratiolet" (" Mem. de " Archiv fiir Anthropologic," iii., 1868. 
la Societe d'Aothropgiogie de Paris," 186S, p. 

220 Tits DESCENT OF MAN. [part t 

The final results of tlieir inquiries may be summed up as follows: 

1. In the human fcx:lus, the Sylvian fissure is formed in the course of 
the third month of utero- gestation. In this and in the fourtli month the 
cerebral hemispheres are smooth and rounded (willi the exception of the 
Sylvian depression), and tliey project backward far beyond the cerebellum. 

2. The sulci, properly so called, begin to appear in the interval between 
the end of the fourth and the beginning of the sixth month of foetal life, 
but Ecker is careful to point out that not only the time, but the order, of 
their appearance is subject to considerable individual variation. In no 
case, however, are either the frontal or the temporal sulci the earliest. 

The first which appears, in fact, lies on the inner face of the hemisphere 
(whence doubtless Gratiolet, who does not seem to have examined that 
f ace in his foetjus, overlooked it), and is either the internal perpendicular 
(occipito-parietal) or the calcarine sulcus, these two being close together 
and eventually running into one another. As a rule the occipito-parietal 
is the earlier of the two. 

3. At the latter part of this period, another sulcus, the * ' posterio-pari* 
etal," or "Fissure of Rolando" is developed, and it is followed, in the 
course of the sixth month, by the other principal sulci of the frontal, pari- 
etal, temporal, and occipital lobes. There is, however, no clear evidence 
that one of these constantly appears before the other ; and it is remark- 
able that, in the brain at the period described and figured by Ecker (1. c, 
p. 212-13, Taf. II. figs. 1,2, 3, 4), the antero-temporal sulcus {scissure 
parallHe), so characteristic of the ape's brain, is as well if not better de- 
veloped than the fissure of Rolando, 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 tliC foetal human brain is in per- 
fect harmony with the general doctrine of evolution, and with the view 
that man has been evolved from some ape-like form ; though there can 
be no doubt that that form was, in many respects, different from any mem- 
ber of the Primates now living. 

Von Baer taught us, half a century ago, that, in the course of their de- 
velopment, allied animals put on, at first, the characters of the greater 
groups to which they belong, and, by degrees, assume those which restrict 
them within the limits of their family, genus, and species ; and he proved, 
at the same time, that no developmental stage of a higher animal is pre- 
cisely similar to the adult condition of any lower animal. It is quite cor- 
rect to say that a frog passes through the condition of a fish, inasmuch as 
j»,t one period of its life the tadpole has all the characters of a fish, and, 
if it went no further, would have to be grouped among fishes. But it is 
equally true that the tadpole is very different from any known fish. 

In like manner, the brain of a human foetus, at the fifth month, may 
correctly be said to be not only the brain of an ape, but that of an Arcto- 
pithecine or marmoset-like ape ; for its hemispheres, with their great pos- 
terior lobes, and with no sulci but the Sylvian and the calcarine, present 
the characteristics found only in the group of the Arctopithecine Primates. 
But it is equally true, as Gratiolet remarks, that, in its widely open Sylvian 
fissure, it differs from the brain of any actual marmoset. No doubt it 
would be much more similar to the brain of an advanced foetus of a mar- 
moset. 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 m the brain of a foetal 
Ctbtis Apella^ in addition to the Sylvian fissure and the deep calcarine 


fissure, only a very shallow antero-temporal fissure {scissure parallUe of 

Now this fact, taken together with the circumstance that the antero-tem- 
poral 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 evi- 
dence in favor of Gratiolet's hypothesis, that the posterior sulci appear 
before the anterior, in the brains of the Platyrhini. But it by no means 
follows that the rule which may hold good for the Plaiyrhini extends to 
the Catarrhini. We have no information whatever respecting the devel- 
opment of the brain in the Cynomorpha : and, as regards the AnthropO' 
morpha, nothing but the account of the brain of the Gibbon, near birth, 
already referred to. At the present moment there is not a shadow of 
evidence to show that the sulci of a chimpanzee's, or orang's, brain do not 
appear in the same order as a man's. 

Gratiolet opens his preface with the aphorism, **I1 est dangereux dans 
les sciences de conclure trop vite.'' I fear he must have forgotten this 
sound maxim by the time he had reached the discussion of the differences 
between men and apes, in the body of his work. No doubt, the excel- 
lent author of one of the most remarkable contributions to the just under- 
Standing of the mammalian brain which has ever been made, would have 
been the first to admit the insufficiency of his data had he lived to profit 
by the advance of inquiry. The misfortune is that his conclusions have 
been employed by persons incompetent to appreciate their foundation, as 
arguments in favor of obscurantism.^^ 

But it is important to remark that, whether Gratiolet was right or wrong 
in his hypolliesis respecting the relative order of appearance of the tem- 
poral and frontal sulci, the fact remains that, before either temporal or 
frontal sulci appear, the foetal brain of man presents characters which are 
found only in the lowest group of the Primates (leaving out the Lemurs); 
and that this is exactly what we should expect to be the case, if man has 
resulted from the gradual modification of the same form as that from which 
the other Primates have sprung. 

*" For example, M. I'AbW Lecomte so his terrible pamnWef, "Le Darwinikio. «.' ^Oll» 

|rffiu»«U I'Uonune," 1873. 




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

With animals which have their sexes separated, the males 
necessarily differ from the females in their organs of reproduc- 
tion ; and these are the primary sexual characters. But the 
sexes often differ in what Hunter has called secondary sexual 
:haracters, which are not directly connected with the act of 
reproduction ; for instance, the male possesses certain organs 
of sense or locomotion of which the female is quite destitute, 
or has them more highly developed, in order that he may 
readily find or reach her ; or again, the male has special organs 
of prehension im 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 com- 
plex appendages at the apex of the abdomen in male insects. 
Unless indeed we confine the term " primary " to the repro- 
ductive glands, it is scarcely possible to decide which ought tc 
be called primary and which secondary. 

CHAP. viii.J SEXUAL SELEC7. ON. 223 

The female often differs from the male in having organs for 
the nourishment or protection of her young, such as the mam- 
mary glands of mammals, and the abdominal sacs of the mar- 
supials. In some few cases also the male possesses similar or- 
gans, which are wanting in the female, such as the receptacles 
for the ova in certain male fishes, and those temporarily de- 
veloped in certain male frogs. The females of most bees are 
provided with a special apparatus for collecting and carryirig 
pollen, and their ovipositor is modified into a sting for the de- 
fence of the larv": -^nd the community. Many similar cases 
could be given, but they do not here concern us. There are, 
however, other sexual differences quite unconnected with the 
primary reproductive organs, and it is with these that we are 
more especially concerned — such as the greater size, strength, 
and pugnacity of the male, his weapons of offence or means 
of defence against rivals, his gaudy coloring and various orna- 
ments, his power of song, and other such characters. 

Besides the prim.ary and secondary sexual differences, sucl 
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 (Culicidas and Tabanidae) are blood- 
suckers, while the males, living on flowers, have mouths desti- 
tute of mandibles.^ The males of certain moths and of some 
crustaceans {e.g.^ Tanais) have imperfect, closed mouths, and 
cannot feed. The complemental males of certain Cirri pedes 
live like epiphytic plants either on the female or the hermaph- 
rodite 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 pos- 
sess. In other cases it is the female which has lost such parts ; 
for instance, the female glow-worm is destitute of wings, as 
also are many female moths, some of which never leave their 
cocoons. Many female parasitic crustaceans have lost their 
natatory legs. In some weevil-beetles (Curculionidae) 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 

* Westwood, "Modern Class- of Insects," 2 gee Kirby and Spence's work, "Intro* 

vol. ii. 1840, p. 541. For the statement about duction to Entomology," volume iil, »^\^ 

Tanais. mentioned below, I am indebted to oage ^og. 
Friu MiiUer. 

224 THE DESCENT OF MAM, [part il 

some few birds the beak of the male differs from that of the 
female. In the Huia of New Zealand the difference is wonder- 
fully great, and we hear from Dr. Bullcr-' that the male luses 
his strong beak in chiselling the larvae of insects out of decayed 
wood, while the female probes the softer parts with her far 
longer, much curved, and pliant beak : and thus they mutually 
aid each other. In most cases, differences of structure between 
the sexes are more or less directly connected with the ])ropaga- 
tion of the species : thus a female, which has to nourish a mul- 
titude of ova, requires more food than the male, and conse- 
quently requires special means for procuring it. A male animal 
which lives for a very short time might lose its organs for pro- 
curing 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 protect- 
ing the young, come under the same influence ; for those indi- 
viduals which generated or nourished their offspring best would 
leave, ccBteris paribus, the greatest number to inherit their 
superiority, while those which generated or nourished their 
offspring badly would leave but few to inherit their weaker 
powers. As the male has to find the female, he requires organs 
of sense and locomotion ; but if these organs are necessary for 
the other purposes of life, as is generally the case, they will 
have been developed through natural selection. When the 
male has found the female, he sometimes absolutely requires 
prehensile organs to iiold 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 because these animals are 

» " Birds of New Zealand," iSys, p. 66. , 


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 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 feniale, it may be that the per- 
fection 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 dis- 
tinction which led me to designate this form of selection as 
Sexual Selection. So again, if the chief service rendered to the 
male by his prehensile organs is to prevent the escape of the 
female before the arrival of other males, or when assaulted by 
them, these organs will have been perfected through sexual selec- 
tion, that is by the advantage acquired by certain individuals 
over their rivals. But in most cases of this kind it is impassible 
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 interest- 
ing than others adapted for the ordinary purposes of life, I shall 
pass them over almost entirely^ giving only a few instances 
under each class. 

* M. Perrier advances this case ("Revue naturalist insists that the claspers of certain 

Scientifiqiie," Feb. i, 1873, p. 865)asone fatal male animals could not have been developed 

to the belieif in sexual selection, inasmuch through the choice of the female ! Had I 

as he supposes that I attribute all the differ- not met with this remark, I should not have 

ences between the sexes to sexual selection, thought it possible for any one to have read 

This distinguished naturalist, therefore, like this chapter and to have imagined that I 

so many other Frenchmen, has not taktn maintain that the choice of the female had 

the trouble to understand even the first anything to do vvah the d'^velopinent of the 

principles of sexual selectios. An English prehensile organs in the nudOf 

226 THE DESCENT OF MAN. \yMLi ii. 

There are many other structures and instincts which must 
have been developed through sexual selection — ^such as the 
weapons of ofience and the means of defence of the males for 
fighting with and driving away their rivals — their courage and 
pugnacity — their various orr.aments — their contrivances for 
producing vocai or instrumental music — and their glands for 
emitting odors, 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 un- 
armed, unornamented, or unattractive males would succeed 
equally well in the battle for life and in leaving a numerous 
])rogeny, but for the presence of better endowed males. We 
may infer that this would be the case, because thi? Temales, 
which are unarmed and unornamented, are able to survive and 
procreate their kind. Secondary sexual characters of the kind 
just referred to will be fully discussed in the following chapters, 
as being in many respects interesting, but especially as depend- 
ing on the will, choice, and rivalry of the individuals of either 
sex. When we behold two males fighting for the possession of 
the female, or several male birds displaying their gorgeous 
plumage, and performing strange antics before an assembled 
body of females, we cannot doubt that, though led by instinct, 
they know what they are about, and consciously exert their 
mental and bodily powers. 

Just as man can improve the breed of his game-cocks by the 
selection of those birds which are victorious in the cock-pit, 
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 variabiHty leading to some ad- 
vantage, however slight, in reiterated deadly contests would 
suffxe 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 ban- 
tam a new and elegant plumage, an erect and peculiar carriage 
— so it appears that female birds in a state of nature have, by a 
long selection of the more attractive males, added to their 
beauty or other attractive qualities. No doubt this implies 
powers of discrimination and taste on the part of the female 
which will at first appear extremely improbable; but, by 
the facts to be adduced hereafter, I hope to be able to show 


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 comparison would be between the taste 
for the beautiful in animals, and that in the lowest savagffs, 
who admire jnd deck themselves with any brilliant, glittering, 
or curious object. 

From our ignorance on several points, the precise manner in 
which sexual selection acts is somewhat uncertain. Neverthe- 
less, if those naturahsts who already believe in the mutability 
of species will read the following chapters, they will, I think, 
agree with me that sexual selection has played an important 
part in the history of the organic world. It is certain that 
among almost all animals there is a struggle between the males 
for the possession of the female. This fact is so notorious that 
it would be superfluous to give instances. Hence the females 
have the opportunity of selecting one out of several males, on 
the supposition that their mental capacity suffices for the exer- 
tion 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 nightingale and blackcap, and with respect to the 
latter he can himself confirm the statement. 

Mr. Swaysland, of Brighton, has been in the habit, during 
the last forty years, of catching our migratory birds on 
their first arrival, and he has never known the females of any 
species to arrive before their males. During one spring he shot 
thirty-nine males of Ray's wagtail {Budytes Raii^ before 
he saw a single female. Mr. Gould has ascertained, by 
the dissection of those snipes which arrive the first in this 
country, that the males come before the females. And the 
like holds good with most of the migratory birds of the United 
States.^ 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 toaas. 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 

• J. A. Allen, on the " Mammals and Winter Birds of Florida," Bull. Comp. Zool* 
ogy, Harvard College, p. a68. 

228 THE DESCEI^rr OF MAIST. [part il. 

before any females can be seen.® The cause of this difference 
between the males and females in their ])eriods of arrival 
and maturity is sufficiently obvious. Those males which an- 
nually first migrated into any country, or which in the spring 
were first ready to breed, or were the most eager, would leave 
the largest numl)er of offspring ; and these would tend to 
inherit similar instincts and constitutions. It must be borne 
in mind that it would have been impossible to change very ma- 
terially the time of sexual maturity in the females, without at 
the jame time interfering with the period of the production of 
the young — a period which must be determined by the seasons 
of the year. On the whole, there can be no doubt that with 
almost all animals, in which the sexes are separate, there is a 
constantly recurrent struggle between the males for the posses- 
sion of the females. 

Our difficulty in regard to sexual selection lies in under- 
standing how it is that the males which conquer other males, 
or those which prove the most attractive to the females, leave 
a greater number of offspring to inherit their superiority than 
their beaten and less attractive rivals. Unless this result does 
follow, the characters which give to certain males an advantage 
over others could not be perfected and augmented through 
sexual selection. When the sexes exist in exactly equal num- 
bers, the worst-endowed males will (except where polygamy 
prevails) ultimately find females, and leave as many offspring, 
as well fitted for their general habits of life as the best- 
endowed males. From various facts and considerations', I 
formerly inferred that with most animals in which secondary 
sexual characters are well developed the males considerably 
exceeded the females in number ; but this is not by any means 
always true. If the males were to the females as two to one, 
or as three to two, or 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 pro- 
portion 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. 

« Even with those plants in which the sexes time, so that they cannot be self^fertilized. 

are separate, the male flowers are generally Now in such flowers, the pollen is in gen- 

mattire before the female. As first shown eral matured before the stigma, though there 

by C. K. Sprengel, many hermaphrodite are exceptional cases in which the lemale 

plants are dichogamous ; that is, their male organs are beforehand, 
and female organs are not ready at the same 

CHAP, viii.i SEXUAL selection: 229 

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 individ- 
uals, and the other of the less vigorous and healthy. The for- 
mer, there can be little doubt, would be ready to breed in the 
spring before the others ; and this is the opinion of Mr. Jenner 
Weir, who has carefully attended to the habits of birds during 
many years. There can also be no doubt that the most vigor^ 
ous, best-nourished, and earliest breeders would on an average 
succeed in rearing the largest number of fine offspring.'' The 
males, as we have seen, are generally ready to breed before the 
females ; the strongest, and with some species the best armedj 
of the males drive away the weaker; and the former would 
then unite with the more vigorous and better-nourished 
females, because they are the first to breed. ^ Such vigorous 
pairs would surely rear a larger number of offspring than the 
retarded females, which would be compelled to unite with the 
conquered and less powerful males, supposing the sexes to be 
numerically equal ; and this is all that is wanted to add, in 
the course of successive generations, to the size, strength, and 
courage of the males, or to improve their weapons. 

But in very many cases the males which conquer their rivals 
do not obtain possession of the females, independently of the 
choice of the latter. The courtship of animal? 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 orna- 
mented 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 observa- 
tion.^ Thus the more vigorous females, which are the first to 
breed, will have the choice of many males ; and, though they 
may not always select the strongest or best armed, they will 
select those which are vigorous and well armed, and in other 
respects the most attractive. Both sexes, therefore, of such 

^ Here is excellent evidence on the char- * Hermann Miiller has come to this same 

acter of the offspring from an experienced conclusion with respect to those female bees 

ornithologist. Mr. j. A. Allen, in speaking which are the first to emerge from the pupa 

^" Mammals and Winter Birds of E. Flori- each year. See his remarkable essay, "An- 

d;»," p. 229) of the later broods, after the wendung den Darwin' schen Lehre auf Bie- 

Rccidantal destruction of the first, says, that nen." " Verh. d. V. Jahrg.." xxix. p. 45. 

these "are foimd to be smaller and paler- * With respect to poultry, I hayc received 

coiored than those hatched earlier in the information, hereafter to be given, to this 

season. In cases where severa' broods are effect. Kven with birds, such a= pigeons, 

reared each year, as a general vule the birds which pair for life, the female, as I hear from 

of the earlier broods .seem m all respects the Mr. Jenner Weir, will desert her mate if he 

moK perfect and vigorous." is injured or grows weak. 

230 THE DESCENT OF MAN. [part it. 

early pairs would, as above explained, have an advantage over 
others in rearing offspring; and this apparently has sufficed 
during a long course of generations to add not only to the 
strength and fighting powers of the males, but likewise to their 
various ornaments or other attractions. 

In the converse and much rarer case of the males selecting 
particular females, it is plain that those which were the most 
vigorous and had conquered others would have the freest 
choice ; and it is almost certain that they would select vigor- 
ous as well as attractive females. Such pairs would have an 
advantage 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 pro- 
viding for the young. The same principles would apply if 
each sex preferred and selected certain individuals of the oppo- 
site sex ; supposing that they selected not only the more at- 
tractive, but likewise the more vigorous individuals. 

Numerical Proportion of the Two Sexes. — I have remarked 
that sexual selection would be a simple affair if the males were 
considerably more numerous than the females. Hence I was 
led to investigate, as far as I could, the proportions between 
the two sexes of as many animals as possible ; but the mate- 
rials are scanty. I will here give only a brief abstract of the 
results, retaining the details for a supplementary discussion, so 
as not to interfere with the course of my argument. Domesti- 
cated animals alone afford the means of ascertaining the pro- 
portional 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 ap- 
pears that with most of our domestic animals the sexes are 
nearly equal at birth. Thus 25,560 births of race-horses have 
been recorded during twenty-one years, and the male births 
were to the female births as 99.7 to 100. In greyhounds the 
inequality is greater than with any other animal, for out of 
6,878 births during twelve years, the male births were to the 
female as iio.i to 100. It is, however, in some degree doubt- 
ful 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 pro- 
portion of the sexes. Thus with mankind, the male births in 
England are as 104.5, ^^ 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 supple- 


ment to this chapter. At the Cape of Good Hope, however, 
male children of European extraction have been born during 
several years in the proportion of between 90 and 99 to 100 
female children. 

For our present purpose we are concerned with the propor- 
tion 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 dur- 
ing birth, and during the first few years of infancy, is consid- 
erably larger than that of females. So it almost certainly is 
with male lambs, and probably with some other animals. 
The males of some species kill one another by fighting, or 
they drive one another about until they become greatly ema- 
ciated. They must also be often exposed to various dangers, 
while wandering about in eager search for the females. In 
many kinds of fish the males are much smaller than the 
females, and they are believed often to be devoured by the lat- 
ter, 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 while in charge of their young. With in- 
sects the female larviie are often larger than those of the males, 
and would consequently be more likely to be devoured. In 
some cases the mature females are less active and less rapid in 
their movements than the males, and could not escape so well 
from danger. Hence, with animals in a state of nature, we 
must rely on mere estimation, in order to judge of the propor- 
tions 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 k">rmed, we may conclude, from 
the facts given in the supplement, that the males of some few 
mammals, of many birds, of some nsh and insects, are consid- 
erably more numerous than the females. 

The proportion between the sexes fluctuates slightly during 
successive years: thus with race-horses, foi 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 numbers been tabulated throughout an area more 
extensive than England, these fluctuations would probably have 
disappeared ; and, such as they are, would hardly suffice to 
lead to effective sexual selection in a state of nature. Never- 
theless, in the cases of some few wild animals, as shown in the 
supplement, the proportions seem to fluctuate either during dif- 
ferent seasons or in different localities in a sufficient degree to 


lead to such selection. For it should be ol^served that any ad- 
vantage gained diirnig certain years or in certain locahties by 
those males which were able to conciuer their rivals, or were 
the most attractive to the females, would probably be trans- 
mitted to the offspring, and would not sul)sequently be elimi- 
nated. During the succeeding seasons, when, from the equal- 
ity of the sexes, every male was able to procure a female, the 
stronger or more attractive males previously jjroduced would 
still have at least as good a chance of leaving offspring as the 
weaker or less attractive. 

Polygamy. — The practice of polygamy leads to the same re- 
sults as would follow from an actual inequality in the number of 
the sexes ; for if each male secures two or more females, many 
males cannot pair ; and the latter assuredly will be the weaker 
or less attractive individuals. Many mammals and some few 
birds are polygamous, but with anima^.s belonging to the lower 
classes I have found no evidence of this habit. The intel- 
lectual powers of such animals are, perhaps, not sufficient to lead 
them to collect and guard a harem of females. That some 
relation exists between polygamy and the development of sec- 
ondary sexual characters, appears nearly certain ; and this sup- 
ports the view that a numerical preponderance of males would 
be eminently favorable to the action of sexual selection. Nev- 
ertheless, many animals which are strictly monogamous, espe- 
cially birds, display strongly marked secondary sexual charac- 
ters ; while some few animals which are polygamous do not 
have such characters. 

We will first briefly run through the mammals, and then turn 
to birds. The gorilla seems to be polygamous, and the male 
differs considerably from the female ; so it is with some baboons, 
which live in herds containing twice as many adult females as 
males. In South America the Mycetes caraya presents well- 
marked sexual differences, in color, beard, and vocal organs; 
and the male generally lives with two or three wives : the male 
of the Cebus capucinus differs somewhat from the female, and 
appears to be polygamous. ^'^ Little is known on this head with 
respect to most other monkeys, but some species are strictly 
monogamous. The ruminants are eminently polygamous, and 
they present sexual differences more frequently than almost any 
other group of mammals ; this holds good especially in their 

i"On the Gorilla, Savage and Wyman, Mycetes, Rengger, " Naturgesch. : Sauge- 

" Boston Journal of Nat. Hist.," vol. v., thiere von Paraguay," 1830,3. 14.20. C«- 

184 -,-47, p. 423. On Cvnocephalus, Brehm, bus, Kiehm, ibid., s. 108. 
•' iilust. Thierleben," B. i., 1864, s. 77. On _-- 


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 Antilope saiga 
appears to be the most inordinate polygamist in the world ; for 
Pallas 1* 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 North America is polygamous, but, 
except in his greater size and in the proportions of his body, 
differs but little from the mare. The wild boar presents well- 
marked sexual characters, in his great tusks and dome other 
points. In Europe and in India he leads a solitary life, except 
during the breeding season ; but, as is believed by Sir W. Elliot, 
who has had many opportunities in India of observing this ani- 
mal, he consorts at this season with several females. Whether 
this holds good in Europe is doubtful, but it is supported by 
some evidence. The adult male Indian elephant, like the boar, 
passes much of his time in solitude ; but, as Dr. Campbell states, 
when with others, ** it is rare to find more than one male with 
a whole herd of females ; " the larger males expelling or kill- 
ing the smaller and weaker ones. The male differs from the 
female in his immense tusks, greater size, strength, and endur- 
ance ; so great is the difference in these respects, that the males 
when caught are valued at one-fifth more than the females. ^^ 
The seAes of other pachydermatous animals differ very little or 
not at all, and, as far as known, they are not polygamists. 
Nor have I heard of any species in the Orders of Cheiroptera, 
Edentata, Insectivora, and Rodents being polygamous, except- 
ing that among the Rodents, the common rat, according to 
some rat-catchers, lives with several females. Nevertheless the 
two sexes of some sloths (Edentata) differ in the character and 
color of certain patches of hair on their shoulders. ^^ And 
many kinds of bats (Cheiroptera) present well-marked sexual 
differences, chiefly in the males possessing odoriferous glands 
and pouches, and by their being of a lighter color. ^' In the 

" Pallas, " Spicllegia Zoolog.," Fasc. xii. 1869, p. 138. See also an interesting paper, 

'777' P- 29- Sir Andrew Smith, " Illustra- by Lieut. Johnstone, in " Proc. Asiatic Soc 

tions of the Zoology of S. Africa," 1840, pi. of Bengal,"" May, 1868. 

29, on the Kobus- Owen, in his "Anatomy '•* Dr. Gray, in "Annals and Mag. of 

of Vertebrates" ,yol. iii. t868, p. 633) gives Nat. Hist." 1871, p. 302. 

a table showing incidentally which species '•• See Dr. Dobson's excellent paper, ia 

of antelopes arc gregarious. "Proc. Zoolog. Soc." 1873, p. 241. 

>» Dr. f;ampbell, in " Proc. Zoolog. Soc" ' J *- ■» 

234 THE DESCENT OF MAN. I^art a 

great order of Rodents, as far as I can learn, the sexes rarely dif- 
fer, and when they do so, it is but slightly in the tint of the fur. 

As I hear from Sir Andrew Smith, the lion in South Africa 
sometimes lives with a single female, but generally with more, 
and, in one case, was found with as many as five females; so 
that he is polygamous. As far as I can discover, he is the only 
polygamist among all the terreslrial 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-elej/hant of the Southern 
Ocean always possesses several females, and the sea- lion of 
Forster is said to be surrounded by from twenty to thirty 
females. In the North, the male sea-bear of Steller is accom- 
panied by even a greater number of females. It is an interest- 
ing fact, as Dr. Gill remarks, ^^ that m the monogamous species, 
*' or Those Hving in small communities, there is" little difference 
in size between the males and females ; in the social species, or 
rather those of which the males have harems, the males are 
vastly larger than the females." 

Among birds, many species, the sexes of which differ greatly 
from each other, are certainly monogamous. In Great Britain 
we see well-marked sexual differences, for instance, in the wild- 
duck which pairs with a single female, the common blackbird, 
and the bullfinch, which is said to pair for life. I am informed 
by Mr. Wallace that the like is true of the Chatterers or Cotin- 
gidae 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 para- 
dise, so remarkable for their sexual differences, are polygamous, 
but Mr. Wallace doubts whether he had sufficient evidence. 
Mr. Salvin tells me he has been led to believe that humming- 
birds are polygamous. The male widow-bird, remarkable for 
his caudal plumes, certainly seems to be a polygamist.^'' I have 
been assured by Mr. Jenner Weir, and by others, that it is some- 
what common for three starlings to frequent the same nest ; 
but whether this is a case of polygamy or polyandry has not 
been ascertained. 

'6 The Eared Seals, "American Natur- Great Bustard, see L. Lloyd, "Game Birds, 

alist," vol. iv., Jan. 1871. of Sweden," 1867, pp. 19 and 182. Montagu 

'""The Ibis," vol. iii. 1861, p. 133, on and Selhy speak of the Black Grouse as 

the Progne Widow-bird. See also or the po!y<::amous, and of the Red Grouse as mo- 

Vidua axillaris, ibid. vol. ii. iSbo, p. 211. nu;j.iiuuus. 
On the polygamy of the Capercaib'° and 


The GalHnaceae exhibit almost as strongly marked sexual 
differences as birds-of-paradise or humming-birds, and many 
ol' the species are, as is well known, polygamous ; others being 
strictly monogamous. What a contrast is presented between 
the sexes of the polygamous peacock or pheasant and the 
monogamous gumea-fowl or partridge ! Many similar cases 
could be given, as in the grouse tribe, in which the males of 
the polygamous capercailzie and black-cock differ greatly from 
the females ; while the sexes of the monogamous red grouse 
and ptarmigan differ very little. In the Cursores, except 
among the bustards, few species offer strongly marked sexual 
differences, and the great bustard ( Otis tarda) is said to be 
polygamous. With the Grallatores, extremely few species dif- 
fer sexually, but the ruff {Machetes pugnax) affords a marked 
exception, and this species is believed by Montagu to be a 
polygamist. Hence it appears that among birds there often 
exists a close relation between polygamy and the development 
of strongly marked sexual differences. I asked Mr. Bartlett of 
the Zoological Gardens, who has had very large experience 
with birds, whether the male tragopan (one of the GalHnaceae) 
was polygamous, and I was struck by his answering, ''I do 
not know, but should think so from his splendid colors." 

It deserves notice that the instinct of pairing with a single 
female is easily lost under domestication. The wild-duck is 
strictly monogamous, the domestic duck highly polygamous. 
The Rev. W. D. Fox informs me that out of some half-tamed 
wild-ducks, on a large pond in his neighborhood, so many 
mallards were shot by the gamekeeper that only one was left 
for every seven or eight females ; yet unusually large broods 
were reared. The guinea fowl is strictly 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 render- 
ing 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 en- 
able 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 female. 

To sum up on the means through which, as far as we can 

»« Noel Humphreys, " River Gardens " •«••- 

236 THE DESCENT OF MAN. Ipart it 

judge, sexual selection has led to the development of secondary 
sexual characters. It has been shown that the largest number 
of vigorous offspring will be reared from the pairing of the 
strongest and best-armed males, victorious in contests over 
other males, with the most vigorous and best-nourished females, 
which are the first to breed in the spring. If such females 
select the more attractive, and at the same time vigorous males, 
they will rear a larger number of offspring than the retarded 
females, which must pair with the less vigorous and less attrac- 
tive males. So it will be if the more vigorous males select the 
more attractive and at the same time healthy and vigorous 
females ; and this will especially hold good if the male defends 
the female, and aids in providing food for the young. The 
advantage thus gained by the more vigorous pairs in rearing a 
larger number of offspring has apparently sufficed to render 
sexual selection efficient. But a large numerical preponderance 
of males over females will be still more efficient ; whether the 
preponderance is only occasional and local, or permanent; 
whether it occurs at birth, or afterward from the greater de- 
struction of the females ; or whether it indirectly follows from 
the practice of polygamy. 

The Male Generally more Modified than the Fetnale.-^ 
Throughout the animal kingdom, when the sexes differ in ex- 
ternal appearance, it is, with rare exceptions, the male which 
has been the more modified ; for, generally, the female retains 
a closer resemblance to the young of her own species, and to 
other adult members of the same group. 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 fight to- 
gether 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 hereafter. That the males of all 
mammals eagerly pursue the females is notorious to everyone. 
So it is with birds ; but many cock birds do not so much pur- 
sue the hen as display their plumage, perform strange antics, 
and pour forth their song in her presence. The male in the 
few fish observed seems much more eager than the female ; 
and the same is true of alligators, and apparently of Batrachi- 
ans. Throughout the enormous class of insects, as Kirby re- 
marks,^^ ** the law is that the male shall seek the female." Two 
good authorities, Mr. Blackwall and Mr. C. Spence Bate, tell 

>• Kirby and Spence, " Introduction to Entomology," vol. iii. i8a6. d. %i2. ^ 


me that the males of spiders and crustaceans are more active 
and more erratic in their habits than the females. When the 
orgaas of sense or locomotion are present in the one sex of in- 
sects 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 in- 
variably the male which retains such organs, or has them most 
developed ; and this shows that the male is the more active 
member in the courtship of the sexes. ^^ 

The female, on the other hand, with the rarest 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 endeavoring for a long time to es- 
cape 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 attrib- 
utable to sexual selection, that the female, though comparatively 
passive, generally exerts some choice and accepts one male in 
preference to others. Or she may accept, as appearances 
would sometimes lead us to believe, not the male which is the 
most attractive to her, but the one which is the least distaste- 
ful. The exertion of some choice on the part of the female 
seems a law almost as general as the eagerness of the male. 

We are naturally led to inquire why the male, in so many 
and such distinct classes, has become more eager than the 
female, so that he searches for her, and plays the more active 
part in courtship. It would be no advantage and some loss of 
power if each sex searched for the other ; but why should the 
male almost always be the seeker ? The ovules of plants after 
fertilization have to be nourished for a time ; hence the pollen is 
necessarily brought to the female organs — being placed on the 
stigma, by means of insects or the wind, or by the spontaneous 
movements of the stamens ; and in the Algae, etc., by the lo- 
comotive power of the antherozooids. With lowly organized 
aquatic animals, permanently affixed to the same spot and 
having their sexes separate, the male element is invariably 
brought to the female ; and of this we can see the reason, for 

'^ One parasitic Hymen opterous insect but it is much more probable that the 

(Westwood, "Modem Class, of Insects," females visit other cells, so that close inter- 

vol. ii. p. ifio) forms an exception to the rule, breeding is thus avoided. We shall here- 

as the male has rudimentary wings, and after meet in various classes with a few ex- 

never quits the cell in which it is born, ceptional cases in which the female, instead 

while the female has well-developed wings, of the male, is the seeker and wooer. 
Audouin believes that the females of this *^ " K.ssays and Observations," edited by 

species are impregnated by the males which Owen, vol. i. 1861, p. 194. 
are bom in the same cells with them ; 

238 THE DESCENT OF MAN, [part ii 

even if the ova were detached before fertilization, 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 fai 
smaller numbers. So that many of the lower animals are, in 
this respect, analogous with plants.^^ The males of affixed and 
aquatic animals having been led to emit their fertilizing ele- 
ment in this way, it is natural that any of their descendants, 
which rose in the scale and became locomotive, should retain 
the same habit ; and they would approach the female as closely 
as possible, in order not to risk the loss of the fertilizing ele- 
ment in a long passage of it through the water. With some few 
of the lower animals, the females alone are fixed, and the males 
of these must be the seekers. But it is difficult to understand 
why the males of species, of which the [)rogenitors were pri- 
mordially free, should invariably have acquired the habit of 
approaching the females, instead of being approached by them. 
But in all cases, in order that the males should seek efficiently, 
it would be necessary that they should be endowed with strong 
passions ; and the acquirement of such passions would naturally 
follow from the more eager leaving a larger number of offspring 
than the less eager. 

The great eagerness of the males has thus indirectly led to 
their much more frequently developing secondary sexual char- 
acters than the females. But the development of such charac- 
ters would be much aided if the "males were more liable to 
vary than the females — as I concluded they were — after a long 
study of domesticated animals. Von Nathusius, who has had 
very wide experience, is strongly of the same opinion.^ Good 
evidence also in favor of this conclusion can be produced by a 
comparison of the two sexes in mankind. During the Novara 
Expedition ^^ a vast number of measurements was made of vari- 
ous 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 conclu- 

21 Prof. Sachs ("Lehrbuch der Botanik," Theil," 1867, s. 216-269. The results were 
1870, s. 633) in speaking of the male and calculated by Dr. Weisbach from measure- 
female reproductive cells, remarks, " Verhalt ments made by Drs. K. Scherzer and 
sicii die eine bei der Vereinigung activ, . . . Schwarz. On the greater variability of the 
die andere erscheint bei der Vereinigung males of domesticated animals, see my 
passiv." '■ Variation of Animals and Plants undci 

23 " Vortrage ilber Vieluucht," 1872, p. Domestication." vol ii. 186S. p. 75. 

§2. ^* " Proceedings Royal Soc." vol. xvi« 

•• "Reise der Novara; Anthropolog. July 1868, pp. 519 and 524. 


sion that '* the greatest number of abnormalities in each sub- 
ject is found in the males." He had previously remarked that 
** altogether in 102 subjects the varieties of redundancy were 
found to be half as many again as in females, contrasting widely 
with the greater frequency of deficiency in females before 
described." Prof. Macalister likewise remarks^ that varia- 
tions in the muscles "are probably more common in males 
than females." Certain muscles which are not normally 
present in mankind are also more frequently developed in the 
male than in the female sex, although exceptions to this rule 
are said to occur. Dr. Burt Wilder ^^ 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 over- 
looked that women would more frequently endeavor to conceal 
a deformity of this kind than men. Again, Dr. L. Meyer as- 
serts 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 ren- 
dered in very many instances widely different from their 
females ; but independently of selection the two sexes, from 
differing constitutionally, tend to vary in a somewhat different 
manner. The female has to expend much organic matter in 
the formation of her ova, whereas the male expends much 
force in fierce contests with his rivals, in wandering about in 
search of the female, in exerting his voice, pouring out odor- 
iferous secretions, etc. ; and this expenditure is generally con- 
centrated within a short period. The great vigor of the male 
during the season of love seems often to intensify his colors, 
independently of any marked difference from the female.'^ In 

as " Proc. Royal Irish Academy," vol. x. '^ Prof. Mantegazza is inclined to believe 

1868, p. 123. (" Lettera a Carlo Darwin," " Archivio per 

2° " Massachusetts Medical Soc." vol. ii. I'Anthropologia," 1871, p. 306) that the bright 

No. 3, 1868, p. 9. colors common in so many male animals are 

" " Archiv fur Path. Anat. und Phys." due to the presence and retention by them 

1871, p. 488. of the spermatic flnid : but this can hardly 

''*' The conclusions recently arrived at by be the case ; for many male birds, for in- 

Dr. J. Stockton-Hough, on the tempcrnture stance yoimg pheasants, become brightly 

of man, are given in the " Pop. Science Re- colored in the autumn of their first y^ar. 
riew," Jan. i, 1874, p. 97. 

240 THE DESCENT OF MA AT. ipart ii. 

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 ver'T 
different ways and at different rates. 

From the causes just specified the two sexes can hard!/ i^!^ 
to differ somewhat in constitution, at least during the breeding 
season ; and, although they may be subjected to exactly the 
same conditions, they will tend to vary in a different manner. 
If such variations are of no service to either sex, they will not 
be accumulated and increased by sexual or natural selection. 
Nevertheless, they may become permanent if the exciting cause 
acts permanently; and, in accordance with a frequent form or 
inheritance, they may be transmitted to that sex alone in which 
they first appeared. In this case the two sexes will come to 
present permanent, yet unimportant, differences of character. 
For instance, Mr. Allen shows that with a large number of 
birds inhabiting the northern and southern United States, 
the specimens from the south are darker-colored than those 
from the north ; and this seems to be the direct result of the 
difference in temperature, light, etc., between the two regions. 
Now, in some few cases, the two sexes of the same species ap- 
pear to have been differently affected ; in the Agelceus phoeniceus 
the males have had their colors greatly intensified in the south; 
whereas with Cardinalis virginianus it is the females which have 
been thus affected ; with Quiscalus major the females have 
been rendered extremely variable in tint, while the males re- 
main nearly uniform. ^^ 

A few exceptional cases occur in various classes of ani- 
mals, in which the females instead of the males have ac- 
quired well pronounced secondary sexual characters, such as 
brighter colors, greater size, strength, or pugnacity. With 
birds there has sometimes been a complete transposition of 
the ordinary characters proper to each sex ; the females hav- 
ing become the more eager in courtship, the males remain- 
ing comparatively passive, but apparently selecting the more 
attractive females, as we may infer from the results. Certain 
hen birds have thus been rendered more highly colored or 
otherwise ornamented, as well as more powerful and pugna- 

■' For mankind, see Dr. J. Stockton- given in the " Zoological Record," 1869, fx 

Hough, whose conclusions are given in the 347. 

" Pop. Science Review," 1874, p. 97. See 3' " Mammals and Birds of E. Florida," 

Girard's observations on the Lepidoptera, as pp. 234, 280, 295. 


cious 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 carric i on ; that the males have selected the 
more attractive females, and the latter the more attractive 
males. This process, hov/ever, though it might lead to the 
modification of both sexes, would not make the one sex dif- 
ferent from the other, unless indeed their tastes for the beauti- 
ful diff"ered ; but this is a supposition too improbable to be worth 
considering in the case of any animal, excepting man. There 
are, however, many animals in which the sexes resemble each 
other, both being furnished with the same ornaments, which 
analogy would lead us to attribute to the agency of sexual 
selection. In such cases it may be suggested with more plausi- 
bility, that there has been a double or mutual process of sexual 
selection ; the more vigorous and precocious females selecting 
the more attractive and vigorous males, the latter rejecting all 
except the more attractive females. But from what we know 
of the habits of animals, this view is hardly probable, for the 
male is generally eager to pair with any female. It is more 
probable that the ornaments common to both sexes were ac- 
quired by one sex, generally the male, and then transmitted to 
the offspring of both sexes. If, indeedTduring a lengthened 
peiriod the males of any species were greatly to exceed the 
females in number, and then during another lengthened period, 
but under different conditions, the reverse were to occur, a 
double, but not simultaneous, process of sexual selection might 
easily be carried on, by which the two sexes might be rendered 
widely different. 

We shall hereafter see that many animals exist of which 
neither sex is brilliantly colored nor prpvided with special orna- 
ments, and yet the members of both sexes or of one alone have 
probably acquired simple coloi*s, such as white or black, through 
sexual selection. The absence of bright tints or other orna- 
ments may be the result of variations of the right kind never 
having occurred, or of the animals themselves having preferred 
plain black or white. Obscure tints have often been developed 
through natural selection for the sake of protection, and the 
acquirement through sexual selection of conspicuous colors 
appears to have been sometimes checked from the danger thus 
incurred. But in other cases the males during long ages may 
have struggled together for the possession of the females, and 
yet no effect will have been produced, unless a larger number 

(K>-Vol. 8 


ofofTspring were left by the more successful males to inherit 
their superiority, than by the less successful : and this, as pre- 
viously shown, 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, in- 
deed, not rarely ensues from the conflicts of rival males. But 
generally the less successful male merely fails to obtain a female, 
or obtains a retarded and less vigorous female later in the 
season, or, if polygamous, obtains fewer females ; so that they 
leave fewer, less vigorous, or no offspring. In regard to struct- 
ures acquired through ordinary or natural selection, there is in 
most cases, as long as the conditions of life remain the same, a 
limit to the amount of advantageous modification in relation to 
certain special purposes ; but in regard to structures adapted to 
make one male victorious over another, either in fighting or in 
charming the female, there is no definite limit to the amount of 
advantageous modification " i0 that as long as the proper vari- 
ations arise the work of sexual selection will go on. This 
circumstance may partly account for the frequent and extra- 
ordinary amount of variability presented by secondary sexual 
characters. Nevertheless, natural selection will determine that 
such characters shall not be acquired by the victorious males, 
if they would be highly injurious, either by 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 favored males derive from conquering other 
males in battle or courtship, and thus leaving a numerous prog- 
eny, 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 distinction in those characters which aie transmitted 
through the early years of life, but are developed only at ma- 
turity or during old age. We see the same distinction more 
clearly with secondary sexual characters, for these are trans- 
mitted through both sexes, though developed in one alone. 
That they are present in both sexes, is manifest when two 
species, having strongly marked sexual characters, are crossed, 
for each transmits the characters proper to its own male and 
female sex to the hybrid offspring of either sex. The same fact 
is likewise manifest when characters proper to the male are 
occasionally developed in the female when she grows old or be- 
comes diseased, as, for instance, when the common hen assumes 
the flowing tail-feathers, hackles, comb, spurs, voice, and even 
pugnacity of the cock. Conversely, the same thing is evident, 
more or less plainly, with castrated males. Again, indepen- 
dently of old age or disease, characters are occasionally trans- 
ferred from the male to the female, as when, in certain breeds 
of the fowl, spurs regularly appear in the young and healthy 
females. But in truth they are simply developed in the female ; 
for in every breed each detail in the structure of the spur is 
transmitted through the female to her male offspring. Many 
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 development of characters in the 
female, and of transferrence to the male, is less frequent ; it will 
therefore be well to give one striking instance. With bees the 
pollen-collecting apparatus is used by the female alone for 
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 

>' H. Miiller, " Anwendung der Darwin'schen Lehre," etc., " Verb. d. n. V. Jabig." 
aodx. p. 42, 

244 THE DESCENT OF MAN. (part it 

females. Lastly, in all cases of reversion, characters are trans- 
mitted through two, three, or many more generations, and are 
then developed under certain unknown favorable conditions. 
This important distinction between transmission and develop- 
ment will be best kept in mind by the aid of the hypothesis of 
pangenesis. According to this hypothesis, every unit or cell of 
the~bddy throws off gemmules or undeveloped atoms, which are 
transmitted to the offspring of both sexes, and are multiplied by 
self-division. They may remain undeveloped during the early 
years of life or during successive generations ; and their devel- 
opment into units or cells, like those from which they were de- 
rived, depends on their affinity for, and union with, other units 
or cells previously developed in the due order of growth. 

Inheritance at Correspo7iding 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 reappear 
in the offspring at the same advanced age. When deviations from 
this rule occur, the transmitted characters much oftener appear 
before than after the corresponding age. As I have dwelt on 
this subject sufficiently in another work,^ I will here merely 
give two or three instances, for the sake of recalling the subject 
to the reader's mind. In several breeds of the Fowl, the down- 
covered chickens, the young birds in their first true plumage, 
and the adults differ greatly from one another, as well as from 
their common parent-form, the Gallus bankiva ; and these 
characters are faithfully transmitted by each breed to their off- 
spring at the corresponding periods of life. For instance, the 
chickens of spangled Hamburgs, while covered with down, 
have a few dark spots on the head and rump, but are not striped 
longitudinally, as in many other breeds; in their first true 
plumage *' they are beautifully pencilled," that is, each feather 
is transversely marked by numerous dark bars ; but in their 
second plumage the feathers all 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 

33 •' The Variation of Animals and Plants Tegetmeiers " Poultry Book," 1868, p. 158. 

under Domestication." vol. ii. 1868, p. 75. On the characters of chickens of different 

In the last chapter but one, the provisional breeds, and on the breeds of the pigeon, al- 

hypothesis of pangenesis, above alluded to, luded ,to in the following paragraph, see 

is fully explained " Variation of Animals," etc., vol. i. pp. i6o^ 

^* These facts are given on the high author- 249 ; vol. ii. p. 77. 
ity of a great breeder, Mr. Teebay ; see 


life. The Pigeon offers a more remarkable case, because the 
aboriginal parent-species does not undergo any change of plu- 
mage with advancing age, excepting that at maturity the breast 
becomes more iridescent ; yet there are breeds which do not 
acquire their characteristic colors until they have moulted two, 
three, or four times; and these modifications of plumage are 
regularly transmitted. 

InJieritance at Corresponding Seasons of the Year. — With 
animals in a state of nature, innumerable instances occur of 
characters appearing periodically at different seasons. We see 
this in the horns of the stag, and in the fur of Arctic animals, 
which becomes thick and white during the winter. Many 
birds acquire bright colors and other decorations during the 
breeding-season alone. Pallas states,^ that in Siberia domestic 
cattle and horses become lighter-colored during the winter ; 
and I have myself observed and heard of similar strongly 
marked changes of color, that is, from brownish cream-color 
or reddish-brown to a perfect white, in several ponies in Eng- 
land. Although I do not know that this tendency to change 
the color of the coat during different seasons is transmitted, yet 
it probably is so, as all shades of color are strongly inherited 
by the horse. Nor is this form of inheritance, as limited by 
the seasons, more remarkable than its limitation by age or sex. 

Inheritance as Limited by Sex. — The equal transmission of 
characters to both sexes is the commonest form of inheritance, 
at least with those animals which do not present strongly 
marked sexual differences, and indeed with many of these. 
But characters are somewhat commonly transferred exclusively 
to that sex in which they first appear. Ample evidence on 
this head has been advanced in my work on '' Variation under 
Domestication," but a few instances may here be given. There 
are breeds of the sheep and goat in which the horns of the 
male differ greatly in shape from those of the female ; and these 
differences, acquired under domestication, are regularly trans- 
mitted to the same sex. As a rule, it is the females alone in cats 
which are tortoise-shell, the corresponding color in the males 
being rusty-red. With most breeds of the fowl, the characters 
proper to each sex are transmitted to the same sex alone. So 
general is this form of transmission that it is an anomaly when 
variations in certain breeds are transmitted equally to both sexes. 

_ " " Novae species Qu2*rupedum e Gil- of Animals, etc.. under Domestication," voL 
rium ordine," 177", p. 7. ^^n the transmis- i. p. 51. Also vol. ii. p. 71, for a general dis- 
sion of color by the horst;, see '' Variation cussion ou " Inheritance as limited by Sex.** 

246 THE DESCENT OF MAN". (part a. 

There are also certain sub-breeds of the fowl in which the 
males can hardly be distinguished from one another, while the 
females differ considerably in color. The sexes of the pigeon 
in the parent-species do not differ in any external character ; 
nevertheless, in certain domesticated breeds the male is colored 
differently from the female.'* The wattle in the English Car- 
rier pigeon and the crop in the Pouter are more highly devel- 
oped in the male than in the female ; and, although these char- 
acters have been gained through long-continued selection by 
man, the slight differences between the sexes are wholly due to 
the form of inheritance which has prevailed ; for they have 
arisen, not from, but rather in opposition to, the wish of the 

Most of our domestic races have been formed by the accu- 
mulation of many slight variations ; and as some of the suc- 
cessive 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 
common. With animals under domestication, but whether in 
nature I will not venture to say, one sex may lose characters 
proper to it, and may thus come somewhat to resemble the 
opposite sex ; for instance, the males of some breeds of the fowl 
have lost their masculine tail-plumes and hackles. On the 
other hand, the differences between the sexes may be increased 
under domestication, as with merino sheep, in which the ewes 
have lost their horns. Again, characters proper to one sex 
may suddenly appear in the other sex ; as in those sub-breeds 
of the fowl in which the hens acquire spurs while young ; or, 
as in certain Polish sub-breeds, in which the females, as there 
is reason to believe, originally acquired a crest, and subse- 
quently transferred it to the males. All these cases are intelli- 
gible on the hypothesis of pangenesis ; for they depend on the 
gemmules of certain partsV although present in both sexes, be- 
coming, 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 Hm- 


CHAP. VIII.] SEXUAL selection: 247 

ited in its development to one sex alone. If, for instance, a 
breeder observed that some of his pigeons (of which the char- 
acters are usually transferred in an equal degree to both sexes) 
varied into pale blue, could he by long-continued selection 
make a breed in which the males alone should be of this tint, 
while the females remained unchanged? I will here only say 
that this, though perhaps not impossible, would be extremely dif- 
ficult ; 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, however, variations of the desired tint appeared, which 
were from the first limited in their development to the male 
sex, there would not be the least difficulty in making a breed 
with the two sexes of a different color, as indeed has been 
effected with a Belgian breed, in which the males alone are 
streaked with black. 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 characterized ; but 
if the variation was not thus originally limited, the process 
would be extremely difficult, perhaps impossible.^ 

On the Relation between the Period of Development of a 
Character and its Transmission to One Sex or to Both Sexes. — 
Why certain characters should be inherited by both sexes, and 
other characters by one sex alone, namely, by that sex in which 
the character first appeared, is in most cases quite unknown. 
We cannot even conjecture why with certain sub-breeds of the 
pigeon, black strise, though transmitted through the female, 
should be developed in the male alone, while every other 
character is equally transferred to both sexes. Why,* again, 
with cats, the tortoise-shell color should, with rare exceptions, 
be developed in the female alone. The very same character, 
such as deficient or supernumerary digits, color-blindness, etc., 
may with mankind be inherited by the males alone of one 
family, and in another family by the females alone, though in 
both cases transmitted through the opposite as well as through 
the same sex.^ Although we are thus ignorant, the two follow- 

•' Since the publication of the first edition gested the possibility of modifying: the sexual 

of this work, it has been highly satisfactory colors of birds by a course of aitificial selec- 

to me to find the following remarks (the tioii. When he did so, he was in ignorance 

" Field," Sept. 1872) from so experienced a of these facts that I have related ; but it is 

breeder as Mr. Tegetmeicr. After describ- remarkable how very closely he suggested 

ing some curious cases in pigeons, of the the right method of procedure." 
transmission of color by one sex alone, and ^* References are given in my " Variation 

the formation of a sub-breed with this char- of Animals under Domestication," vol. ii. p. 

acter, he says : '* It is a singular circum- 72, 
Stance that Mr. Darwin should have sug- 

.^^48 THE DESCENT OF MAN. [part il 

ing rules seem often to hold good — that variations wliich first 
appear in either sex at a late period of life tend to be developed 
in the same sex alone, while variations which first appear 
early in life in either j;:x tend to be developed in both sexes. 
I am, however, far from supposing that this is the sole deter- 
mining cai;:;e. As I have not elsewhere discussed this subject, 
and as it has an important bearing on sexual selection, I must 
here enter into lengthy and somewhat intricate details. 

It is in itself probable .that any character appearing at an 
early age would tend to be inherited equally by both sexes, 
for the sexes do not differ much in constitution before the 
power of reproduction is gained. On the other hand, after 
this power has been gained and the sexes have come to differ 
in constitution, the gemmules (if I may again use the language 
of pangenesis) which are cast off from each varying part in the 
one sex would be much more likely to possess the proper affin- 
ities for uniting with the tissues of the same sex, and thus be- 
coming developed, than with those of the opposite sex. 

I was first led to infer that a relation of this kind exists, from 
the fact that whenever and in whatever manner the adult male 
differs from the adult female, he differs in the same manner 
from the young of both sexes. The generality of this fact 
is quite remarkable : it holds good with almost all mammals, 
birds, amphibians, and fishes ; also with many crustaceans, 
spiders, and some few insects, such as certain orthoptera and 
libellulae. In all these cases the variations, through the accu- 
mulation of which the male acquired his proper masculine char- 
acters, must have occurred at a somewhat late period of life ; 
otherwise the young males would have been similarly charac- 
terized ; 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 
fule, during youth. But there is here room for doubt, for 
characters are sometimes transferred to the offspring at an ear- 
lier 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 while young. 
There are, moreover, many animals in which the two sexes 
closely resemble each other, and yet both differ irpm their 


young ; and here the characters of the adults must have been 
acquired late in Ufe ; nevertheless, these characters, in appar- 
ent contradiction to our rule, are transferred to both sexes. 
We must not, however, overlook the possibftity, or even prob- 
abilty, of successive variations of the same nature occurring, 
under exposure to similar conditions, simultaneously in both 
sexes at a rather late period of life ; and in this case the vari- 
ations would be transferred to the offspring of both sexes at & 
corresponding late age ; and there would then be no real contra- 
diction to the rule that variations occurring late in life are trans- 
ferred exclusively to the sex in which they first appeared. This 
latter rule seems to hold true more generally than the second one, 
namely, that variations which occur in either sex early in life 
tend to be transferred to both sexes. As it was obviously impos- 
sible even to estimate in how large a number of cases through- 
out the animal kingdom these two propositions held good, it 
occurred to me to investigate some striking or crucial instances, 
and to rely on the result. 

An excellent case for investigation is afforded by the Deer 
family. In all the species but one the horns are developed 
only in the males, though certainly transmitted through the 
females, and capable of abnormal development in them. In 
the reindeer, on the other hand, the female is provided with 
horns ; so that in this species the horns ought, according to 
our rule, to appear early in life, long before the two sexes are 
mature and have come to differ much in constitution. In all 
the other species the horns ought to appear later in life, which 
would lead to their development in that sex alone in which 
they first appeared in the progenitor of the whole Family. 
Now in seven species, belonging to distinct sections of the 
family and inhabiting different regions, in which the stags 
alone bear horns, I find that the horns first appear at periods 
varying from nine months after birth in the roebuck, to ten, 
twelve, or even more months, in the stags of the six other and 
larger species.^ But with the reindeer the case is widely dif- 
ferent ; for, as I hear from Prof. Nilsson, who kindly made 
special inquiries for me in Lapland, the horns appear in the 
young animals within four or five weeks after birth, and at the 

•" I am much obliged to Mr. Cupples for Cerrms alces of N. America, see " Land and 

having made inquiries for me in regard to Water," 1868, pp. 221 and 254; and for the 

the Roebuck and Red Deer of Scodand from C. Virgi>iianus and strongyloceros of the 

Mr. Kobertson, the experienced head forest- same continent, see J. D. Caton, in " Otta- 

er to the Marq\iis of l^readalbane. In re- wa Acad, of Nat. Sc." 1868, p. 13. For 

gard to Fallow-deer, I have to thank Mr. Cervus Eldi of Pegu, see I.ieut. Beavan, 

Eytonand others for information. For the "Proc. Zoolog. Soc." 1867, p. 762. 

250 THE DESCENT OF AfAiV. [part it. 

same time in both sexes. So that here we have a structure, 
developed at a most unusually early age in one species of the 
family, and likewise common to both sexes in this one species 

In several kinds of antelopes, only the males are provided 
with horns, while in the greater number both sexes bear 
horns. With respect to the period of development, Mr. Blyth 
informs me that there was at one time in the Zoological Gar- 
dens a young koodoo (^;;/. strcpsiccros)^ of which the males 
alone are horned, and also the young of a closely allied species, 
the eland {Ant. 'areas), in which both sexes are horned. Now 
it is in strict conformity with our rule, that m the young male 
koodoo, although ten months old, the horns were remarkably 
small, considering the size ultimately attained by them ; while 
in the young male eland, although only three months old, the 
horns were already very much larger than in the koodoo. It 
is also a noticeable fact that in the prong-horned antelope,'"' 
only a few of the females, about one in five, have horns, and 
these are in a rudimentary state, though sometimes above four 
Inches long ; so that, as far as concerns the possession of horns 
by the males alone, this species is in an intermediate condi- 
tion, and the horns do not appear until about five or six months 
after uirth. Therefore, in comparison with what little we know 
of the development of the horns in other antelopes, and from 
what we do know with respect to the horns of deer, cattle, etc., 
those of tfie prong-horned antelope appear at an intermediate 
period of liic?— that is, not very early, as in cattle and sheep, 
nor very late, as in the larger deer and antelopes. The horns 
of sheep, goats, and cattle, which are well developed in both 
sexes, though not quite equal in size, can be felt, or even seen, 
at birth or soon afterward.^^ Our rule, however, seems to fail 
in some breeds of sheep, for instance, merinos, in which the 
rams alone are horned ; for I cannot find on inquiry ^^ that the 
horns are developed later in life in this breed than in ordinary 

*^ Atttilocapra Americana. I have to *' I am greatly indebted to Prof. Victor 

thank Dr. Canfield for information with re- Cams for havin? made inquiries for me, 

spect to the horns of the female : see also his from the highest authorities, with respect 

paper in " Proc. Zoolog. Soc." 1866, p 109. to the merino sheep of Saxony. On the 

Also Owen, " Anatomy of Vertebrates," vol. Guinea coast of Africa there is, however, a 

iii. p. 627. breed of sheep in which, as with merinos, the 

4' I have been assured that the horns of rams alone bear horns ; and Mr. Winwood 

the sheep in North Wales can always be felt, Reade informs me that in one case observed 

and are sometimes even an inch in length, by him a young ram, born on Feb. loth, 

at birth. Youatt says (" Cattle," 1S34. p. first showed horns on March 6th, so that in 

277), that the prominence of the frontal bone this instance, in conformity with rule, the 

in cattle penetrates the cutis at birth, and development of the horns occurred at a latet 

that the homy matter is soon formed over period of life than in Welsh sheep, in whicb 

it, both sexes are homed. 


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 Pheas- 
ants, the males differ conspicuously from the females, and they 
acquire their ornaments at a rather late period of life. The 
eared pheasant {^Crossoptiloii aurituni), however, offers a re- 
markable exception, for both sexes possess the fine caudal 
plumes, the large ear-tufts, and the crimson velvet about the 
head ; I find that all these characters appear very early in life, 
in accordance with rule. The adult male can, however, be 
distinguished from the adult female by the presence of spurs ; 
and, conformably with our rule, these do not begin to be de- 
veloped before the age of six months, as I am assured by Mr. 
Bartlett, and even at this age the two sexes can hardly be dis- 
tinguished.-'*'^ The male and female Peacock differ conspicu- 
ously fiom 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 some- 
what smaller in the female, and it is developed early in life, 
while the curled tail-feathers and other ornaments of the male 
are developed later. '*^ Between such extreme cases of close 

*3 'I Ueber die knbchemen Schadelhocker April 23, 1869, there was no difference in 

der Vogel," in the " Niederlandischen Ar- the development of the spurs. The spurs, 

chiv fiir Zoologie," Band I. Heft 2, 1872. however, were as yet represented merely by 

'•■' In the common peacock {Pavo crista- slight knobs or elevations. I presume that 

tus) the male alone possesses spurs, while I should have been informed if any difference 

both sexes of the Java peacock (/'. w«//r«5-) in the rate of development had been ob- 

offer the unusual case of being furnished served subsequendy. 

with spurs. Hence I fully expected that in *6 \^ some other species of the Duck 
the latter species they would have been de- family the specuhnn differs in a greater de- 
veloped earlier in life than in the common gree in the two sexes ; but I have not been 
peacock; but M. Hegt of Amsterdam in- able to discover whether its full development 
forms me that with youug birds of the occurs later in life in the males of such 
previous year, of both species, compared on species tlian in the male of the conunoD 

252 THE D/CSCE/VT OE MAN'. [part il 

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 con- 
dition, it is doubtful whether the period of development can 
determine the transferrence of their characters to one or to both 
sext^. But we do not know that the colored scales, for in- 
stance, m two species of butterflies, in one of which the sexes 
differ in color, while in the other they are alike, are developed 
at the same relative age in the cocoon. Nor do we know 
whether all the scales are simultaneously developed on the 
wings of the same species of butterfly, in which certain colored 
marks are confined to one sex, while others are common to both 
sexes. A difference of this kind in the period of development 
is not so improbable as it may at first appear ; for with the 
Orthoptera, which assume their adult state not by a single 
metamorphosis, but by a succession 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 

We have as yet considered the transferrence of characters, 
relatively to their period of development, only in species in a 
natural state ; we will now turn to domesticated animals, and 
first touch on monstrosities and diseases. The presence o£ 
supernumerary digits, and the absence of certain phalanges, 
must be determined at an early embryonic period — the ten- 
dency to profuse bleeding is at least congenital, as is probably 
color-blindness — yet these peculiarities, and other similar ones, 
are often hmited in their transmission to one sex ; so that the 
rule that characters developed at an early period tend to be 
transmitted to both sexes, here wholly fails. But this rule, as 
before remarked, does not appear to be nearly so general as the 
converse one, namely, that characters which appear late in life 
in one sex are 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 

duck, as ought to be the case according to the young males at first entirely resemble the 

our rule. With the allied Mergus cuculla- females, and have a grayish-white speculum, 

/«,r we have, however, i case of this kind : which becomes pure white at an earlier age 

tHe two sexes differ coMspicuously in general than that at which the adult male acquires 

pkimage, and to a considerable degree in his other and more strongly marked sexual 

fcie specuiura, which is pure white in the differences: see Audubon, "Ornithological 

BDale and grayisli-white in the female. Now Biography," vol. iii. 1835, pp. 249-250. ^ 


infer that there must be some difference between the sexes at an 
extremely early age. With respect to sexually limited diseiises, 
we know too little of the period at which they originate, to 
draw any safe conclusion. Gout, however, seems to fall under 
our rule, for it is generally caused by intemperance during 
'manhood, and is transmitted from the father to his sons in a 
much more marked manner than to his daughters. 

In the various domestic breeds of sheep, goats, and cattle, 
the males differ from their respective females in the shai)e or 
development of their horns, forehead, mane, dewlap, tail, and 
hump on the shoulders ; and these pecuHarities, 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 fut- 
ure chapter, the male goes on increasmg in size to an unusually 
late period of life, which, according to rule, will account for 
his increased size being transmitted to his male offspring alone. 
On the other hand, the tortoise-shell color, which is confined 
to female cats, is quite distinct at birth, and this case violates 
the rule. There is a breed of pigeons in which the males alone 
are streaked with black, and the streaks can be detected even in 
the nestlings ; but they become more conspicuous at each suc- 
cessive moult, so that this case partly opposes and partly sup- 
ports the rule. With the English Carrier and Pouter pigeons, 
the full development of the wattle and the crop occurs rat> er 
late in life, and, conformably with the rule, these characters 
are transmitted in full perfection to the males alone. The fol- 
lowing 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 pe- 
riod ; and if so, these cases are not opposed to our rule : 
There exist sub-breeds of the pigeon, described by Neumeister,^^ 
in which both sexes change their color during two or three 
moults (as is likewise the case with the Almond Tumbler) ; 
nevertheless, these changes, though occurring rather late in 
life, are common to both sexes. One variety of the Canary- 
bird, namely, the London Prize, offers a nearly analogous case. 

With the breeds of the Fowl the inheritance of various char- 
acters by one or both sexes seems generally determined by th^ 

«• ~* Das GanzederTaubenzucht," 1837, s. eons, see Dr. Chapuis, "Le pigeon voy 
%U «4' F^ *be c»«e of the streaked pig- ageur Beige/' 1865, p. 87. 

254 THE DESCENT OF MAN. (part tt 

period at which such characters are develoi)ed. Thus in all 
the many breeds in which the adult male differs greatly in 
color from the female, as well as from the wild i)arent-species, 
he differs also from the young male, so that the newly acfjuired 
characters must have appeared at a rather late period of life. 
On the other hand, in most of the breeds in which the two 
sexes resemble each other, the young are colored in nearly the 
same manner as their parents, and this rendeiB it probable that 
their colors first appeared early in life. We have instances of 
this fact in all black and white breeds, in which the young and 
old of both sexes are alike ; nor can it be maintained that 
there is something peculiar in a black or white plumage which 
leads to its transferrence to both sexes ; for the males alone of 
many natural species are either black or white, the females be- 
ing differently colored. With the so-called Cuckoo sub-breeds 
of the fowl, in which the feathers are transversely pencilled 
with dark stripes, both sexes and the chickens are colored in 
nearly the same manner. The laced plumage of the Sebright 
bantam is the same in both sexes, and in the young chickens 
the wing-feathers are distinctly, though imperfectly, laced. 
Spangled Hamburgs, however, offer a partial exception ; for the 
two sexes, though not quite alike, resemble each other more 
closely than do the sexes of the aboriginal parent-species ; yet 
they acquire their characteristic plumage late in life, for the 
chickens are distinctly pencilled. With respect to other char- 
acters besides color, in the wild-parent species and in most of 
the domestic breeds, the males alone possess a well-developed 
comb ; but in the young of the Spanish fowl it is largely de- 
veloped 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 won- 
derfully early age, of which curious proofs could be given ; 
and this character is transmitted to both sexes, so that the 
hens, from their extreme pugnacity, are now generally ex- 
hibited in separate pens. With the Polish breeds the bony 
protuberance of the skull which supports the crest is partially 
developed even before the chickens are hatched, and the crest 
itself soon begins to grow, though at first feebly ; ^"^ and in this 
breed the adults of both sexes are characterized by a great bony 
protuberance and an immense crest. 

*^ For full particulars and references on 256. In regard to the higher animals, the 

all these points respecting the several breeds sexual differences which have arisen under 

of the Fowl, see " Variation of Animals and domestication are described in the samf 

Plants under Domestication," voL i. pp. 25^ work under the head of each species. 


Finally, from what we have now seen of the relation which 
exists in many natural species and domesticated races, between 
the period of the development of their characters and the man- 
ner 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, while the sexes differ but 
little in constitution. It appears, however, that some difference 
must exist between the sexes even during a very early embry- 
onic period, for characters developed at this age not rarely 
become attached to one sex. 

Summary and Concluding Rejnarks. — From the foregoing 
discussion on the various laws of inheritance, we learn that the 
characters of the parents often, or even generally, tend to be- 
come developed in the offspring of the same sex at the same 
age, and periodically at the same season of the year, in which 
they first appeared in the parents. But these rules, owing to 
unknown causes, are far from being fixed. Hence, during the 
modification of a species, the successive changes may readily be 
transmitted in different ways ; some to one sex, and some to 
both ; some to the offspring at one age, and some to the 
offspring at all ages. Not only are the laws of inheritance 
extremely complex, but so are the causes which induce and 
govern variability. The variations thus induced are preserved 
and accumulated by sexual selection, which is in itself an 
extremely complex affair, depending, as it does, on the ardor 
in love, the courage, and the rivalry of the males, as well as 
on the powers of perception, the taste, and will of the female. 
Sexual selection v/ill also be largely dominated by natural 
selection tending toward the general welfare of the species. 
Hence the manner in which the individuals of either or both 
sexes have been affected through sexual selection cannot fail to 
be complex in the highest degree. 

When variations occur late in life in one sex, and are trans- 
mitted to the same sex at the same age, the other sex and the 
young are left unmodified. When they occur late in life, but 
are transmitted to both sexes at the same agf», the young alone 
are left unniodified. Variations, however, may occur at any 

250 THE DESCENT OF MA V. Iparv h 

period of life in one sex or in both, and be transmitted to both 
sexes at all ages, and then all the individuals of the species are 
similarly modified. In the following chai)ters 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. I'roiri the great eagerness of the male 
it has generally acted on this sex, and not on the females. Tiie 
males have thus become provided with weapons for fighting 
with their rivals, with organs for discovering and securely hold- 
ing the female, and for exciting or charming her. When the 
sexes differ in these respects, it is also, as we have seen, an 
extremely general law that the adult male differs more or less 
from the young male : and we may conclude from this fact that 
the successive variations by which the adult male became 
modified did not generally occur much before the age for 
reproduction. Whenever some or many of the variations oc- 
curred early in life, the young males would partake more or less 
of the characters of the adult miales ; and differences of this kind 
between the old and young males may be observed in many 
species of animals. 

It is probable that young male animals have often tended to 
vary in a manner w^hich would not only have been of no use to 
them at an early age, but w^ould have been actually injurious — ■ 
as by acquiring bright colors, which would render them con- 
spicuous to their enemies, or by acquiring structures, such as 
great horns, which would expend much vital force in their 
development. Variations of this kind occurring in the young 
males would almost certainly be eliminated through natural 
selection. With the adult and experienced males, on the othei 
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 con- 
quering 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 acciden- 
tal deaths. Consequently, in a state of nature, if variations of 
the above kind chanced to arise in the female Hne, and to be 
transmitted exclusively in this hne, they would be extremely 
liable to be lost. If, however, the females varied and tram- 


mitted 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 con- 
tingencies. Lastly, the females may acquire, and apparently 
have often acquired by transferrence, characters from the male 

As variations occurring late in life, and transmitted to one 
sex alone, have incessantly been taken advantage of and accu- 
mulated through sexual selection in relation to the reproduc- 
tion of the species ; therefore it appears, at first sight, an 
unaccountable fact that similar variations have not frequently 
been accumulated 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. Dif- 
ferences 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 func- 
tions, in which respect the sexes necessarily differ. For varia- 
tions in structure which are related to these functions have 
often proved of value to one sex, and, from having arisen at a 
late period of life, have been 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 sex- 
ual characters in animals of all classes, and shall endeavor in 
each case to apply the principles explained in the present chap- 
ter. 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 illustra- 
tive 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 thf 
male conquers other males, and by which he allures or excites 
the female, will be fully discussed, as these are in many wayg 
the most interesting. 

358 THE DESCENT OF MAN, [part n 

Supple?nent on the Proportional Numbers of the Two Sexes tu 
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 king- 
dom, I will here give such materials as I have been able to col- 
lect, 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 cer- 
tainty only in mankind, 1 will first give them as a standard of 

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 ^'^^Iqs 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 Bucking- 
hamshire (where about 5,000 children are annually born) the 
mean proportion of male to female births, during the whole 
period of the above ten years, was as 102.8 to 100; while in 
North Wales (where the average annual births are 12,873) it 
was as high as 106.2 to 100. Taking a still smaller district, 
viz., Rutlandshire (where the annual births average only 739), 
in 1864 the male births were as 114.6, and in 1862 as only 
97.0 to 100 ; but even in this small district the average of the 
7,385 births, during the whole ten years, was as 104. 5 to 100 ; 
that is in the same ratio as throughout England. ""^ The pro- 
portions are sometimes slightly disturbed by unknown causes; 
thus Prof. Faye states '' that in some districts of Norway there 
kas been during a decennial period a steady deficiency of boys, 
while in others the opposite condition has existed." In France 
during forty-four years the male to the female birtlis have been 
as 106.2 to 100; but during this period it has occurred five 
times in one department, and six times in another, that the 
female births have exceeded the males. In Russia the average 
proportion is as high as 108.9, ^^^ ^^ Philadelphia, in the 
United States, as 110.5 to 100.^^ The average for Europe, de- 
duced by Bickes from about seventy million births, is 106 

<8 "Twenty-ninth Annual Report of the nuairepourl'An 1867," p. 213. For Philadel- 

Registrar-General for 1866." In this report phia. Dr. Stockton-Hough, '• Social Science 

(p. xii.) a special decennial table is given. Assoc." 1874. For the Cape of Good Hope, 

*" For Norway and Russia, see abstract Quetelet as quoted by Dr. H. H. Zouteveen, 

of Prof. Faye's researches, in " British and in the Dutch translation of this work (vol. i. 

Foreign Medico-Chirurg. Review," April, p. 417), where much information is givoo <* 

1867, pp. 343, 345. For France, the " An- the proportion of the sexes. 


males to loo females. On the other hand, with white chil- 
dren born at the Cape of Good Hope, the proportion of males 
is so low as to fluctuate during successive years between 90 and 
99 males for every 100 females. It is a singular fact that with 
Jews the proportion of male births is decidedly larger than 
with Christians: thus in Prussia the proportion is as 113, in 
Breslau as 114, and in Livonia as 120 to 100; the Christian 
births in these countries being the same as usual, for instance, 
in Livonia as 104 to 100.^ 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, dur^ 
ing the first year, 126 boys die for every 100 girls — a propor' 
tion which in France is still more unfavorable."^^ Dr. 
Stockton-Hough accounts for these facts in part by the more 
frequent defective development of males than of females. We 
have before seen that the male sex is more variable in strucc 
ure than the female ; and variations in important organs would 
generally be injurious. But the size of the body, an i especially 
of the head, being greater in male than female infants is an- 
other cause ; for the males are thus more liable to be injured 
during parturition. Consequently the still-born males are more 
numerous; and, as a highly competent judge. Dr. Crichton 
Browne,^ 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 subsequently, 
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 statistic.?,! records have been kept,^ are found 
to preponderate considerably over the males. 

*® In regard to the Jews, see M. Thury, death-rate is an impressed, natural, and 

**LaLoi de Production des Sexes," 1863, constitutional pec\iliarity due to sex alone." 

p. 25. 53 "West Riding Lunatic Asylum Rc- 

"" British and Foreign Medico-Chirurg. ports." vol. i. 1871, p. 8. Sir J. Simpson 

Review," April, 1867, p. 343. Dr. Stark has proved that the head of the male infant 

also remarks ("Tenth Annual Report of exceeds that of the female by three eighths 

Births, Deaths, etc., in Scotland." 1867, p. of an inch in circumference, and by one- 

Xxviii.) that "These examples may suffice eighth in transverse diameter. Quetelethas 

to show that, at almost every stage of life, shown that woman is horn smaller than man ; 

the males in Scodand have a greater liability see Dr. Duncan, "Fecundity, Fertility, 

to death and a higher death-rate than the SterlHty." 1871, p. 382. 

females. The fact, however, of this pecu- ^^ \v',th ^hg savage Guaranys of Paraguay- 

liarity being most strongly developed at that according to the accurate Azara (" Voyages 

infantile period cf life when the dress, food, dans TAmerique merid." torn. ii. 1800, pp. 

fend general treatment of both sexes are 60. 171;^, the women are to the men in vOt 

■like, soems to prove that the higher male proportion of 14 to i.^ 


It sceins at first sight a mysterious fact that in difTerent na- 
tions, under different conditions and chmates, in Naples, Prus- 
sia, Westphalia, Holland, France. P^ngland, and the United 
States, the excess of male over femile births is less when they 
are illegitimate than when legitimate.^* This has been ex- 
plained by different writers in many different ways, as from the 
mothers being generally young, from Che large proportion of 
first pregnancies, etc. But we have seen that male infants, 
from the large size of their heads, suffer more than female in- 
fants during parturition, and as the mothers of illegitimate 
children must be more liable than other women to undergo bad 
labors, from various causes, such as attempts at concealment by 
tight lacing, hard work, distress of mind, etc., their male in- 
fants would proportionably suffer. And this probably is the 
most efficient of all the causes of the proportion of aiales to 
females born alive being less among illegitimate children than 
among the legitimate. With most animals the greater size of 
the adult male than of the female is due to the stronger males 
having conquered the weaker in their struggles for the posses- 
sion of the females, and no doubt it is owing to this fact that 
the two sexes of at least some animals differ in size at birth. 
Thus we have the curious fact that we may attribute the more 
frequent deaths of male than female infants, especially among 
the illegitimate, at least in part to sexual selection. 

It has often been supposed that the relative age of the two 
parents determines the sex of the offspring ; and Prof. Leuck- 
art ^ has advanced what he considers sufficient evidence, with 
respect to man and certain domesticated animals, that this is 
one important though not the sole factor in the result. So 
again the period of impregnation relatively to the state of the 
female has been thought by some to be the efficient cause ; but 
recent observations discountenance this belief. According to 
Dr. Stockton-Hough,^ the season of the year, the poverty or 
wealth of the parents, residence in the country or in cities, the 
crossing of foreign immigrants, etc., all influence the propor- 
tion 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 sub- 
ject in the harems of Siam, and concludes that the proportion 

W Kabbage, " Edinburgh Journal o^ Sci- *6 Leuckart (in Wagner " HandwortWi 

ence," iSzy, vol. i. p. 88 ; also p. 90, on buch der Phys." B. iv. 1853, s. 774* 

still-born children. On illegitimate children ^6 Social Science Assoc, of Phila., 187^^ 

U England, see " Report of Registrar- ^7 '^Anthropological Review," April, itfO^ 

Gener^ for i?66," p. xv. »• cviii. 


of male to female births is the same as from monogamous 
unions. Hardly any animal has been rendered so highly po- 
lygamous as the English race-horse, and we shall immediately 
see that his male and female offspring are almost exactly eciiial 
in number. I will now give the facts which I have collected 
with respect to the proportional numbers of the sexes of van 
ous animals ; and will then briefly discuss how far selection has 
come into play in determining the result. 

Horses. — Mr. Tegetmeier has been so kind as to tabulate for 
me from the " Racing Calendar " the births of race-horses dur- 
ing a period of twenty-one years, viz., from 1846 to 1867 ; 
1849 being omitted, as no returns were that year published. 
The total births were 25,560,^^ consisting of 12,763 males and 
12,797 females, or in the proportion of 99.7 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 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. i, and in 1867 as only 
92.6, to 100 females. In the tabulated returns the proportions 
vary in cycles, for the males exceeded the females during six 
successive years ; and the females exceeded the males during 
two periods each of four years : this, however, may be acci- 
dental ; at least I can detect nothing of the kind with man in 
the decennial table in the Registrar's Report for 1866. 

Dogs. — During a period of twelve years, from 1857 to 1868, 
the births of a large number of greyhounds, throughout England, 
were sent to the Field newspaper ; and I am again indebted 
to Mr. Tegetmeier for carefully tabulating the results. The 
recorded births were 6,878, consisting of 3,605 males and 
3,273 females, that is, in the proportion of iio.i males to 100 
females. The greatest fluctuations occurred in 1864, when the 
proportion was as 95.3 males, and in 1867, as 11 6. 3 males to 
100 females. The above average proportion of iio.i to 100 
is probably nearly correct in the case of the greyhound, but 
whether it would hold with other domesticated breeds is in 

•* During eleven years a record was kept from one-third of the mares failed to produce 

of the nunfber of mares which proved barren hving foals. Thus during 1866, 809 male 

or prematurely jlipped their foals ; and it colts and 816 female colts were bom, and 

deserves notice, as showing how infertile 743 marcs failed to produce offspring. Dur- 

these hbhly nurtured and rather closely- mg 1867, 836 males and 902 fem^cs WWf 

iDterteed animals have become, that not £ur born, and 794 mares faiicdt . _ 

262 THE DESCENT OE MAN. [part ii. 

some degree doubtful. Mr. Cupples has inquired from several 
great breeders of dogs, and finds that all, without excej)tion, l)c- 
lieve 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 im- 
pression on the mind. 

Sheep. — The sexes of sheep are not ascertained by agricult- 
urists 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 pro- 
portion of males would be somewhat larger at birth than at the 
age of castration. This is a remarkable coincidence with what, 
as we have seen, occurs with mankind, and both cases proba- 
bly depend on the same cause. I have received returns from 
four gentlemen in England who have bred Lowland sheep, 
chiefly Leicesters, during the last ten to sixteen years ; they 
amount altogether to 8,965 births, consisting of 4,407 males 
and 4,558 females; that is in the proportion of 96.7 males to 
100 females. With respect to Cheviot and black-faced sheep 
bred in Scotland, I have received returns from six breeders, 
two of them on a large scale, chiefly for the years 1867-69, 
but some of the returns extend back to 1862. The total num- 
ber 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-calves; i.e., in the proportion of 94.4 
males to 100 females. The Rev. W. D. Fox informs me that 
in 1867, out of 34 calves born on a farm in Derbyshire, only 
one was a bull. Mr. Harrison Weir has inquired from several 
breeders of Pigs, and most of them estimate the male to the 

*' I am much indebted to Mr. Cupples for premature deaths of the males — a st^temeni 

having procured for me the above returns subsequently confirmed by Mr. Aitchison 

from Scotland, as well as some of the follow- and others. To this latter gentleman, and 

ing returns on cattle. Mr. R. Elliot, of to Mr. Payan, I owe tav thank* for laq|0 

Lwghwood, first caiied my attention to the returns as to sheC|N 


lemale births as about 7 to 6. This same gentleman has bred 
Rabbits for many years, and has noticed that a far greater num- 
ber of bucks are produced than does. But estimations are of 
little value. 

Of mammalia in a state of nature I have been able to learn 
very little. In regard to the common rat, I have received con- 
flicting statements. Mr. R. Elhot, of Laighwood, informs 
me that a rat-catcher assured him that he had always found the 
males in great excess, even with the young in the nest. In 
consequence of this, Mr. Elliot himself subsequently examined 
some hundred old ones, and found the statement true. Mr. F. 
Buckland has bred a large number of white rats, and he also 
believes that the males greatly exceed the females. In regard to 
Moles, it is said that "the males are much more numerous 
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 South Africa ^^ (^Kobus 
ellipsiprymnics)^ remarks that, in the herds of this and other spe- 
cies, the males are few in number compared with the females : 
the natives believe that they are born in this proportion \ others 
believe that the younger males are expelled from the herds, and 
Sir A. Smith says that, though he has himself never seen herds 
consisting of young males alone, others affirm that this does 
occur. It appears probable that the young, when expelled from 
the herd, would often fall a prey to the many beasts of prey of 
the country. 

Birds. — With respect to the Fowl, I have received only one 
account, namely, that out of 1,001 chickens of a highly bred 
stock of Cochins, reared during eight years by Mr. Stretch, 
487 proved males, and 514 females; i.e., as 94.7 to 100. In 
regard to domestic pigeons, there is good evidence either that 
the males are produced in excess, or that they live longer; 
for these birds invariably pair, and single males, as Mr. Teget- 
meier informs me, can always be purchased cheaper than 
females. Usually the two birds reared from the two eggs laid 
in the same nest are a male and a female , but Mr. Harrison 
Weir, who has been so large a breeder, says that he has often 
bred two cocks from the same nest, and seldom two hens ; 
moreover, the hen is generally the weaker of the two, and more 
liable to perish. 

With respect to birds in a state of nature, Mr. Gould and 

«" Bdl, *' History of British Quadrupeds," «> "Illustrations of the Zoology «f S. 
p. 100, Africa," 1849, pi. 29. 

264 7'^^ DESCENT OF If AN. [part ii. 

others* are convinced that the males are generally the more 
numerous ; and as the young males of many si)ecies resemble 
the females, the latter would naturally ai)pear to Ije the more 
numerous. Large numbers of jjheasants are reared by Mr. 
Baker, of Leadenhall, from eggs laid by wild birds, and he in- 
forms Mr. Jenner Weir that four or five males to one female are 
generally produced. An experienced observer remarks^ that 
in Scandinavia the broods of the capercailzie and blackcock 
contain more males than females; and that with the Dal-ripa 
(a kind of ptarmigan) more males than females attend the ieks 
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 I 
have been assured that this is the case in Scotland. Mr. Weir, 
on inquiring from the dealers, who receive at certain seasons large 
numbers of ruffs (^Machetes pugnax), was told that the males 
are much the more numerous. This same naturalist has also 
inquired for me from the bird-catchers, who annually catch 
an astonishing number of various small species alive for the 
London market, and he was unhesitatingly answered by an old 
and trustworthy man, that with the chaffinch the males are in 
large excess ; he thought as high as 2 males to i female, or at 
least as high as 5 to 3.^ The males of the blackbird, he like- 
wise 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 {Lmaria mon- 
fana), and goldfinch. On the other hand, he is certain that 
with the common linnet the females preponderate greatly, but 
unequally during different years ; during some years he has 
found the females to the males as four to one. It should, how- 
ever, be borne in mind that the chief season for catching birds 
does not begin till September, so that with some species par- 
tial migrations may have begun, and the flocks at this period 
often consist of hens alone. Mr. Salvin paid particular at- 

*' Brehm (' Illust. Thierleben," 6. iv. s. following year. To show the rmmher of 

990) comes to the same conclusion. living chaffinches caught. 1 may mention 

«' On the authority of L. Lloyd, " Game that in 1869 there was a match between two 

Birds of Sweden," 1867. pp. 12, 132. experts, and one man caught in a day 62, 

«* " Nat. Hist, of Selbome," letter xxix. and another 40, male chaffinches. The 

edit, of 1825, vol. i. p. 139. greatest number evei caught by one man ia 

•* Mr. Jenner Weir received similar in- a single day was 70. 
formation, on making inquiries during the 


tention to the sexes of the humming-birds in Central America, 
and he is convinced that with most of the species the males are 
in excess , thus one year he procured 204 specimens belonging 
to ten species, and these consisted of 166 males and of only 38 
females. With two other species the females were in excess ; 
but the proportions apparently vary either during different sea- 
sons or in different localities; for on one occasion the males of 
Campy lopterus hemileuciirus were to the females as 5 to 2, and 
on another occasion^ in exactly the reversed ratio. As bear- 
ing on this latter point, I may add, that Mr. Powys found in 
Corfu and Epirus the sexes of the chaffinch keeping apart, and 
'' the females by far the most numerous; " while in Palestine 
Mr. Tristram found '■'■ the male flocks appearing greatly to ex- 
ceed the female in number." ^^ So again with the Qinscahcs 
major, Mr. G. Taylor *^^ says that in Florida there were ''very 
few females in proportion to the males," while in Honduras the 
proportion was the other way, the species there having the 
character of a polygamist. 

Fish. — With Fish the proportional numbers of the sexes 
can be ascertained only by catching them in the adult or nearly 
adult state ; and there are many difBculties in arriving at any 
just conclusion.''^ Infertile females might readily be mistaken 
for males, as Dr. Giinther has remarked to me in regard to 
trout. With some species the males are believed to die soon 
after fertilizing the ova. With many species the males are of 
much smaller size than the females, so that a large number of 
males would escape from the same net by which the females 
were caught. M. Carbonnier ''^ who has especially attended to 
the natural history of the pike {Esox iucius), states that many 
males, owing to their small size, are devoured by the larger 
females ; and he believes that the males of almost ail fish are 
exposed from this same cause to greater danger than the 
females. Nevertheless, in the few cases in which the propor- 
tional numbers have been actually observed, the males ap- 
pear to be largely in excess. Thus Mr. R. Buist, the superin- 
tendent of the Stormontfield experiments, says that in 1865, out 
of 70 salmon first landed for the purpose of obtaining the ova, 
upward of 60 were males. In 1867 he again "calls attention 
to the vast disproportion of the males to the females. We had 

'•"Ibis," vol. ii. p. 260, as quoted in •" Leuckart quotes Bloch (, 

Gould's "Trochilida;," i86i, p. 52. For " Handworterbuch der Phys." 13. iv. 1853, 

the foregoing prof)ortions I am indebted to s. 775), that with fish there are twice as 

Mr. Salvin for a table of his results. many males as females. 

«' *' Ibis," i860, p. 137 : and 1867, p. 369. ■"> Quoted in the " Farmer," March 18* 

" " Ibis," 1862, p. 137. 1869, p. 369. 

(L)— Vol. 3 


at the outset at least ten males to one female.'* Afterward 
females sufiicient 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 i?ivariably hap- 
pens that when the first rush of fish is made to the net, there 
will be at least seven or eight males to one female found cap- 
tive. I cannot quite account for this ; either the males are 
more numerous than the females, or the latter seek safety by 
concealment rather than flight." He then adds, that by care- 
fully 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, bream, 
and minnow, appear regularly to follow the practice, rare in 
*ihe animal kingdom, of polyandry ; for the female while 
sj-awning is always attended by two males, one on each side, 
and in the case of the bream, by three or four males. This fact 
is so well known, that it is always recommended to stock a 
pond with two male tenches to one female, or at least with three 
males to two females. With the minnow, an excellent observer 
states that on the spawning-beds the males are ten times as 
numerous as the females; when a female comes among the 
males, **she is immediately pressed closely by a male on each 
side ; and when they have been in that situation for a time, 
are superseded by other two males. ' ' '^ 

Insects. — In this great Class the Lepidoptera almost alone 
afford means for judging of the proportional numbers of the 
sexes ; for they have been collected with special care by many 
good observers, and have been largely bred from the Qgg 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 find that 

" "The Stormontfield Piscicultural Ex- 1826, p. 307; on the CyPrinus carpio, p. 

periments," 1866, p. 23. The "Field" 331 ; on the 7i«c-a z/^/^arzV, p. 331 ; on the 

newspaper, June 29, 1867. Abramis brama, p. 336. See, for the 

'' "Land and Water," 1868, p. 41. minnow {Leuciscus pho.vinus), "Loudon' 

»« Yarrell, " Hist. British Fishes," vol. i. Mag. of Nat. Hist." vol. v. 1832, p. 682. ^ 


this has ever been done. The general opinion appears to 
be that the sexes are nearly equal ; but in Italy, as I hear 
from Prof. Canestrini, many breeders are convinced that the 
females are produced in excess. This same naturalist, how- 
ever, informs me that in the two yearly broods of the Ailan- 
thus silk-moth {Bombyx cynthid), the males greatly prepon- 
derate in the first, while in the second the two sexes are 
nearly equal, or the females rather in excess. 

In regard to Butterflies in a state of nature, several observers 
have been much struck by the apparently enormous preponder- 
ance of the males.*^ Thus Mr. Bates, '^ 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 proportion of a hundred to one. In 
North America, Edwards, who had great experience, estimates 
in the genus Papilio the males to the females as four to one ; 
and Mr. Walsh, who informed me of this statement, says that 
with P. turnus this is certainly the case. In South Africa, 
Mr. R. Trimen found the males in excess in 19 species ;''^ and 
in one of these, which swarms in open places, he estimated the 
number of males as fifty to one female. With another species, in 
which the males are numerous in certain localities, he collected 
only five females during seven years. In the island of Bourbon, 
M. Maillard states that the males of one species of Papilio 
are twenty times as numerous as the females."" 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 perhaps 
offer an exception. Mr. Wallace "^ states that the females of 
Ornithoptera crceszis, in the Malay archipelago, are more com- 
mon and more easily caught than the males ; but this is a rare 
butterfly. I may here add, that in Hyperythra, a genus of 
moths, Guenee says that from four to five females are sent in 
collections from India for one male. 

When this subject of the proportional numbers of the sexes 
of insects was brought before the Entomological Society,"^ it 
was generally admitted that the males of most Lepidoptera, in 
the adult or imago state, are caught in greater numbers than 

'* Leuckart quotes Meinecke (Wagner, Trimen in his "Rhopalocera Africae Au»- 

•' Handworterbuch der Phys." B. iv. 1853, tralis." 

B. 775) that the males of Butterflies are three '^ Quoted by Trimen, "Transact. Ent 

or four times as numerous as the females. Soc." vol. v. part iv. 1866, p. 330. 

'* "The Naturalist on the Amazons," vol. ''^ "Transact. Linn. Soc." vol. xxv. p. 37. 

K. 1863. pp. 228. 347. "^ *■ Proc. F.ntoroolog. Soc." Fda. «7» 

^ " Foiu of these cases are given by Mr. 1868. ' 

268 THE DESCENT OF MAN, Cpart vl 

the females; but this fact was attributed by various o])servers 
to the more retiring habits of the females, and to the males 
emerging earlier from the cocoon. This latter circumstance is 
well known to occur with most Lepidoptera, as well as with 
other insects. So that, as M. Personnat remarks, the males of 
the domesticated Bombyx Yamaviai are 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 the great excess of males in the above cases 
of certain butterflies which are extremely com.mon in their 
native countries. Mr. Stainton, who has paid very close atten- 
tion during many years to the smaller moths, informs me that 
when he collected them in the imago state, he thought that the 
males were ten times as numerous as the females, but that, since 
he has reared them on a large scale from the caterpillar state, 
he is convinced that the females are the more numerous. 
Several entomologists concur in this view. Mr. Doubleday, 
however, and some others take an opposite view, and are 
convinced that they have reared from the eggs and caterpillars 
a larger proportion of males than of females. 

Besides the more active habits of the males, their earlier 
emergence from the cocoon, and in some places their frequenting 
more open stations, other causes may be assigned for an appar- 
ent or real difference in the proportional numbers of the sexes 
of Lepidoptera, when captured in the imago state, and when 
reared from the o^gg or caterpillar state. I hear from Prof. 
Canestrini, that it is believed by many breeders in Italy that 
the female caterpillar of the silk-moth suffers more from the 
recent disease than the male, and Dr. Staudinger informs me 
that in rearing Lepidoptera more females die in the cocoon 
than males. With many species the female caterpillar is larger 
than the male, and a collector would naturally choose the firxest 
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 v/ould probably devour the largest ; and Prof. 
Canestrini informs me that in Italy some breeders believe, 
though on insufficient evidence, that in the first broods of the 
Ailanthus silk-moth the wasps destroy a larger number of the 
female than of the male caterpillars. Dr. Wallace further 

•0 Quoted by Dr. Wallace in " Proc. Ent. Soc." 3d series, vol. v, 1867, p. 487. 


remarks that female caterpillars, from being larger than the 
mples, require more time for their development, and consume 
more food and moisture ; and thus they would be exposed 
during a longer time to danger from ichneumons, birds, etc., 
and in times of scarcity would perish in greater numbers. 
Hence it appears quite possible that, in a state of nature, fewer 
female Lepidoptera may reach maturity than males ; and for 
our special object we are concerned with their relative numbers 
at maturity, when the sexes are ready to propagate their kind. 

The manner in which the males of certain moths congregate 
in extraordinary numbers round a single female apparently 
indicates a great excess of males, though this fact may perhaps 
be accounted for by the earlier emergence of the males from 
their cocoons. Mr. Stain ton informs me that from twelve to 
twenty males may often be seen congregated round a female 
Elachista rufocinerea. It is well known that if a virgin Lasio- 
canipa quercus or Saturnia carpmi be exposed in a cage, vast 
numbers of males collect round her, and, if confined in a room, 
will even come down the chimney to her. Mr. Doubleday 
believes that he has seen from fifty to a hundred males of both 
these species attracted in the course of a single day by a female 
in confinement. In the Isle of Wight Mr. Trimen exposed a 
box in which a female of the Lasiocampa had been confined on 
the previous day, and five males soon endeavored to gain 
admittance. In Australia, M. Verreaux, having placed the fe- 
male 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 

Mr. Doubleday has called my attention to M. Staudinger's^ 
list of Lepidoptera, which gives the prices of the males and 
females oif 300 species of well-marked varieties of butter- 
flies (Rhopalocera). The prices for both sexes of the very 
common species are of course the same; but in 114 of the 
rarer species they differ ; the males being in all cases, excepting 
one, the cheaper. On an average of the prices of the 113 
species, the price of the male to that of the female is as 100 to 
149 ; and this apparently indicates that inversely the males ex- 
ceed the females in the same proportion. About 2,000 species 
or varieties of moths (Heterocera) are catalogued, those with 
wingless females being here excluded on account of the differ- 
ence in habits between the two sexes : of these 2,000 species, 

8* Blanchard. " Mfetamorphoses, Moeurs ^"^ " Lepidopteren - Doublctten Lisle,* 
des Inscctcs," x868, pp. 225-326. Bcr)i«, No. x. 




141 differ in price according to sex, the males of 130 being 
cheaper, and those of only 11 being dearer, than the femah^s. 
The average price of the males of the 130 species, to that of 
the females, is as loo to 143. With resjjcct to the butterflies 
in this priced list, Mr. Doubleday thinks (and no man in Eng- 
land has had more experience) that there is nothing in the 
habits of the species which can account for the difference in the 
prices of the two sexes, and that it can be accounted for only 
by an excess in the number of the males. But I am bound to 
add that Dr. Staudinger informs me that he is himself of a 
different opinion. He thinks that the less active habits of the 
females and the earlier emergence of the males will account for 
his collectors securing a larger number of males than of females, 
and consequently for the lower prices of the former. With 
respect to specimens reared from the caterpillar state, Dr. 
Staudinger believes, as previously stated, that a greater number 
of females than of males die while confined in the cocoons. 
He adds that with certain species one sex seems to preponderate 
over the other during certain years. 

Of direct observations on the sexes of Lepidoptera, reared 
either from eggs or caterpillars, I have received only the few 
following cases : 

The Rev. J. Hellins,^^ of Exeter, reared, during 1868, ) 

images of 73 species, which consisted of . . . ) 
Mr. Albert Jones, of Eltham, reared, during 1868, ) 

imagos of 9 species, which consisted of . . . f 
During 1869 he reared imagos from 4 species, con- ) 

sisting of ) 

Mr. Buckler, of Emsworth, Hants, during 1869, I 

reared imagos from 74 species, consisting of . . ^ 
Dr. Wallace, of Colchester, reared from one brood of ) 

Bombyx cynthia f 

Dr. Wallace raised, from cocoons of Bombyx Pernyi ) 

sent from China, during 1869 \ 

Dr. Wallace raised, during 1868 and 1869, from two ) 

lots of cocoons of Bombyx yama-mai . . . . f 




















So that in these eight lots of cocoons and eggs, males were 
produced in excess. Taken together, the proportion of males 

•3 This naturalist has been so kind as to but so many of the fi^^ures were estimates, 
send me some resuks from former years, in that I foumd it impossible to tabulate them* 
which the females seemed to preponderate \ 


13 as 122.7 to 100 females. But the numbers are hardly large 
enough to be trustworthy. 

On the whole, from these various sources of evidence, all 
pointing in the same direction, I infer that with most species of 
Lepidoptera, the mature males generally exceed the females in 
number, whatever the proportions may be at their first emer- 
gence from the egg. 

With reference to the other orders of insects, I have been 
able to collect very httle reliable information. With the stag- 
beetle {Liuanus cervus) ^' the males appear to be much more 
numerous than the females;" but when, as Cornelius re- 
marked during 1867, an unusual number of these beetles ap- 
peared in one part of Germany, the females appeared to exceed 
the males as six to one. With one of the Elateridse, the males 
are said to be much more numerous than the females, and 
''two or three are often found united with one female;^' so 
that here polyandry seems to prevail." With Siagonium 
(Staphylinidce), in which the males are furnished with horns, 
" the females are far more numerous than the opposite sex." 
Mr. Janson stated at the Entomological Society that the fe- 
males of the bark-feeding Tornicus villosus are so common as 
to be a plague, while the males are so rare as to be hardly 

It is hardly worth while saying anything about the propor- 
tion of the sexes in certain species and even groups of insects, 
for the males are unknown or very rare, and the females are 
parthenogenetic, that is, fertile, without sexual union ; exam- 
ples of this are afforded by several of the Cynipidae.^ In all 
the gall-making Cynipidae known to Mr. Walsh, the females 
are four or five times as numerous as the males ; and so it is, 
as he informs me, with the gall-making Cecidomyiiae (Dip- 
tera). With some common species of Saw-flies (Tenthredinae) 
Mr. F. Smith has reared hundreds of specimens from larvae of 
all sizes, but has never reared a single male ; on the other hand, 
Curtis says,^*' that with certain species (Athalia) bred by him, 
the males were to the females as six to one ; while exactly the 
reverse occurred with the mature insects of the same species 
caught in the fields. In the family of Bees, Hermann Muller^ 
collected a large number of specimens of many species, and 

"* Giinther's "Record of Zoological Lit- ** Walsh, in "The American Entomolo- 

erature," 1867, p. 260. On the excess of gist," vol. i. 1869, p. 103. F. Smith, "Rec- 

female Lucanus, ibid. p. 250. On the males ord of Zoological Literature," 1867, p. 328. 

of Lucanus in England, Westwood, " Mod- "' " Farm Insects," pp. 45-46. 

em Class, of Insects," vol. i. p. 187. On the •*' " Anwendung der Darwin'schcn Lehr^* 

Siagonium, ibid. p. 172. "Vcrh, d. n. V. Jahrg." xxiv. 

272 THE DESCENT OF MAN. [part n. 

reared others from the cocoons, and counted the sexes. He 
found that the males of some species greatly exceeded the 
females in number ; in others the reverse occurred ; and in 
others the two sexes were nearly e(]ual. But as in most cases 
the males emerge from the cocoons before the females, they are 
at the commencement of the breeding season practically in ex- 
cess. Miiller also observed that the relative number of the two 
sexes in some species differed much in different localities. Bit 
d& H. Miiller has himself remarked to me, these remarks must 
be received with some caution, as one sex might more easily 
escape observation than the other. Thus his brother, Fritz 
Miiller, has noticed in Brazil that the two sexes of the same 
species of bee sometimes frequent different kinds of flowers. 
With respect to the Orthoptera, I know hardly anything about 
the relative number of the sexes ; Korte,**"^ however, says that, 
out of 500 locusts which he examined, the males were to the 
females as five to six. With the Neuroptera, Mr. Walsh states 
that in many, but by no means in all the species of the Odona- 
tous group, there is a great overplus of males ; in the genus 
Hetcerina, also, the males are generally at least four times as 
numerous as the females. In certain species in the genus 
Gomphus the males are equally in excess, while in two other 
species the females are twice or thrice as numerous as the 
males. In some European species of Psocus thousands of fe- 
males may be collected without a single male, while with other 
species of the same genus both sexes are common.® In Eng- 
land, Mr. Macl^achlan has captured hundreds of the female 
Apatama multebris, but has never seen the male ; and of 
Boreus hyemalis only four or five males have been seen here.^ 
With most of these species (excepting the Tenthredinae) there 
is at present no evidence that the females are subject to par- 
thenogenesis ; and thus we see how ignorant we are of the 
causes of the apparent discrepancy in the proportion of the two 

In the other Classes of the Articulata I have been able to 
collect still less information. With Spiders, Mr. Blackwall, 
who has carefully attended to this class during many years, 
writes to me that the males, from their more erratic habits, are 
more commonly seen, and therefore appear more numerous. 
This is actually the case with a few species ; but he mentions 

^ " Die Strich-, Zug- oder Wanderheii- " Proc. Ent. Soc. Philadelphia," Oct. 1863, 

schrecke," 1828, p. 20. pp. 168, 223, 239. 

"* "Observations on N. American Neu- *" "Proc Jtnt. Soc. London," Feb. 1^ 

JOj^tera," by H. Hageo and B. D, Walsh* x868. 


several species in six genera, in which the females appear to be 
much more numerous than the males. ^^ The small size of the 
males in comparison with the females (a peculiarity which is 
sometimes carried to an extreme degree), and their widely dif- 
ferent appearance, may account in some instances for their 
rarity in collections.^^ 

Some of the lower Crustaceans are able to propagate their 
kind asexually, and this will account for the extreme rarity of 
the males ; thus Von Siebold ^'^ carefully examined no less than 
13,000 specimens of Apus from twenty-one localities, and 
among these he found only 319 males. With some other forms 
(as Tanais and Cypris), as Fritz Miiller informs me, there is 
reason to believe that the males are much shorter lived than 
the females; and this would explain their scarcity, supposing 
the two sexes to be at first equal in number. On the other 
hand, Miiller has invariably taken far more males than females 
of the Diastylidse and of Cypridina on the shores of Brazil ; 
thus with a species in the latter genus, 63 specimens caught 
the same day included 57 males ; but he suggests that this pre- 
ponderance may be due to some unknown difference in the 
habits of the two sexes. With one of the higher Brazilian 
crabs, namely, a Gelasimus, Fritz Miiller found the males to be 
more numerous than the females. According to the large ex- 
perience of Mr. C. Spence Bate, the reverse seems to be the 
case with six common British crabs, the names of which he has 
given me. 

The Proportion of the Sexes in Relation to Natural Selection, 

There is reason to suspect that in some cases man has by 
selection indirectly influenced his own sex-producing powers. 
Certain women tend to produce during their whole lives more 
children of one sex than of the other ; and the same holds good 
of many animals, for instance, cows and horses ; thus Mr. 
Wright, ofYeldersley 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 peculiar- 

•' Another great authority with respect to " See, on this subject, Mr. O. P. Cam- 

this class, Prof. Thorcll of Upsala ("On bridge, as quoted in "Quarterly Journal o4 

European Spiders," 1869-70, part i. p. 205) Science," 1868, p. 429. 

speaks as if female Bpider.s were generally '^ " Beitrage zur Parthenogenesis," ^ 

fraunoaer than the males, 174* 

274 ^^^^ DESCENT OF MAN! (part il 

ity, for instance, that of producing twins ; and concerning the 
above tendency a good authority, Mr. J. Downing, has com- 
municated to me facts which seem to prove that this does 
occur in certain famihes of short-horn cattle. Col. Marshall '•** 
has recently found on careful examination that the Todas, a 
hill-tribe of India, consist of 112 males and 84 females of all 
ages — that is in a ratio of 1333 males to 100 females. The 
Todas, who are polyandrous in their marriages, during former 
times invariably practised female infanticide ; but this practice 
has now been discontinued for a considerable period. Of the 
children born within late years, the males are more numerous 
than the females, in the proportion of 124 to 100. Col. 
Marshall accounts for this fact in the following ingenious man- 
ner : " Let us for the purpose of illustration take three families 
as representing an average of the entire tribe; say that one 
mother gives birth to six daughters and no sons ; a second 
mother has six sons only, while the third mother has three 
sons and three daughters. The first mother, following the tri- 
bal 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 while 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 infanti- 
cide seems almost certain ; that is if we assume that a sex-pro- 
ducing tendency is inherited. But as the above numbers are 
so extremely scanty, I have searched for additional evidence, 
but cannot decide whether what I have found is trustworthy ; 
nevertheless the facts are, perhaps, worth giving. The Maories 
of New Zealand have long practised infanticide ; and Mr. 
Fenton^^ states that he ''has met with instances of women 
who have destroyed four, six, and even seven children, mostly 
females. However, the universal testimony of those best quali- 
fied to judge is conclusive that this custom has for many years 
been almost extinct. Probably the year 1835 may be named 
as the period of its ceasing to exist. ' ' Now among the New 
Zealanders, as with the Todas, male births are considerably in 

•* "The Todas,** 1873, pp. lOOi lii, 194, * "Aboriginal Inhabitants of New 7a» 
J96, land ; GoverRiReot Ileport^" ?839» P« 3^ 


excess. Mr. Fenton remarks (p. 30): ''One fact is certain, 
although the exact period of the commencement of this singu* 
lar condition of the disproportion of the sexes cannot be de- 
monstratively fixed, it is quite clear that this course of decrease 
was in full operation during the years 1830 to 1844, when the 
non-adult population of 1844 was being produced, and has 
continued with great energy up to the present time." The 
following statements are taken from Mr. Fenton (p. 26), but, 
as the numbers are not large, and as the census was not accu- 
rate, 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 civil- 
ized countries, chiefly owing to the greater mortality of the 
male sex during youth, and partly to accidents of all kinds 
later in life. In 1858 the native population of New Zealand 
was estimated as consisting of 31,667 males and 24,303 fe- 
males of all ages, that is in the ratio of 130.3 males to 100 
females. But during this same year, and in certain limited dis- 
tricts, 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 «^«- 
aduU females 142, that is in the ratio of 125.3 to 100. It 
may be added that in 1844, at which period female infanticide 
had only lately ceased, the non-adult males in one district were 
281, and the non-adult females only 194, that is in the ratio 
of 144.8 males to 100 females. 

In the Sandwich Islands the males exceed the females in 
number. Infanticide was formerly practised there to a fright- 
ful extent, but was by no means confined to female infants, as 
is shown by Mr. Ellis,^ and as I have been informed by Bishop 
Staley and the Rev. Mr. Coan. Nevertheless, another appar- 
ently trustworthy writer, Mr. Jarves,^' whose observations ap- 
ply to the whole archipelago, remarks : " Numbers of women 
are to be found who confess to the murder of from three to 
six or eight children ; " and he adds, '* females, from bei»g 
considered less useful than males, were more often destroyed." 
From what is known to occur in other parts of the world, this 
statement is probable, but must be received with much cau- 
tion. The practice of infanticide ceased about the year 1819^ 

'• "Narrative of a Tour through Hawaii," »^ " History of the Sa&Uwtcb Ulacds^* 
tlaC, p, 298. 1843, p. 9» 



when idolatry was abolished and missionaries settled in the 
Islands. A careful census in 1839, of the adult and taxable 
men and women in the island of Kauai and in one district of 
Oahu (Jarves, p. 404), gives 4^723 males and 3,776 females; 
that is in the ratio of 125.08 to 100. At the same time the 
number of males under fourteen years in Kauai, and under 
eighteen in Oahu was 1,797, and of females of the same ages 
1,429; and here we have the ratio of 125.75 males to 100 

In a census of all the islands in 1850,^ the males of all ages 
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 9,593, or as 112.3 to 
100. From the census of 1872 the proportion of males of all 
ages (including half-castes) to females is as 125.36 to 100. 
It must be borne in mind that all these returns for the Sand- 
wich Islands give the proportion of living males to living fe« 
males, and not of the births ; and, judging from all civilized 
countries, the proportion of males would have been consider- 
ably higher if the numbers had referred to births.^ 

From the several foregoing cases we have some reason to be- 
lieve 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 lead- 

98 This is given in the Rev. H. T. Chee- I had hoped to gain some light on this 

vet's " Life in the Sandwich Islands," 1851, subject from the breeding of dogs ; inas- 

p. 277. ^ much as in most breeds, with the exception, 

•• Dr. Coulter, in describing ('•Journal perhaps, of greyhounds, many more female 

R. Geograph. Soc." vol. v. 18^5, p. 67), the puppies are destroyed than males, just as 

state of California about the year 1830, says with the Toda mfants. Mr. Cupples 

that the natives, reclaimed by the Spanish assures me that this is usual with Scotch 

missionaries, have nearly all perished, or deer-hounds. Unfortunately', I know noth- 

are perishing, although well treated, not ing of the proportion of the sexes in any 

driven from their native land, and kept breed, excepting greyhounds, and there the 

from the use of spirits. He attributes tnis, male births are to the female as no. i to 100. 

in great part, to the undoubted fact that the Now from inquiries made from many 

men greatly exceed the wo.nen in number ; breeders, it seems that the females are in 

but he does not know whether this is due to some respects more esteemed, though other- 

a failure of female offspring, or to more fe- wise troublesome ; and it does not appear 

males dying during earlj' youth. The latter that the female puppies of the best-bred dogs 

alternative, accordmg to all analogy, is very are systematically destroyed more than the 

improbable. He adds that " mfanticide, males, though this does sometimes take 

properly so called, is not common, though place to a limited extent. Therefore I am 

very frequent recourse is had to abortion." unable to decide whether we can, on the 

If Dr. Coulter is correct about infanticide, above principles, account for the preponder- 

this case cannot be ad\anced in support of ance of male births in greyhounds. On the 

Col. Marshall's view. From the rapid de- other hand, we have seen that with horses, 

crease of the reclaimed natives, we may sus- cattle, and sheep, which are too valuable 

pect that, as in the cases lately given, their for the young of either sex to be destroyed, 

fertility has been diminished from changed if there is any difference, the females an 

habits of life^'v slightly in excess. 


ing to this result in decreasing races which have akeady be- 
come somewhat infertile. Besides the several causes previously 
alluded to, the greater facility of parturition among savages, 
and the less consequent injury to their male infants, would 
tend to increase the proportion of live-born males to females. 
1'here 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 Tahi- 
tians 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 cer- 
tain 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 mere numerous descend- 
ants. In the case of mankind the advantage arising from 
having a preponderance 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 in- 
dividuals more than to others; for instance, an individual 
with a tendency to produce more males than females would not 
succeed better in the battle for life than an individual with an 
opposite tendency ; and therefore a tendency of this kind couid 
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 fertilization 
^f the female ; and the males accordingly largely preponderate, 

:78 THE DESCEiVT OF MANr. \vKvci ft 

but it is by no means obvious how this malc-[)roducing ten- 
dency could have been acquired. I formerly thought that 
when a tendency to produce the two sexes in ecjual numbers 
was advantageous to the species, it would follow from natural 
selection, but I now see that the whole problem is so intricate 
that it is safer to leave its solution for the future. 



These characters absent in the lowest classes — Brilliant colors — Mollusca 
— Annelids — Crustacea, secondary sexual characters stn^ngly devel- 
oped ; dimorphism ; color ; characters not acquired before maturity 
—Spiders, sexual colors 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 sec- 
ondary sexual characters cannot be developed. In many cases 
where the sexes are separate, both are permanently attached to 
some support, and the one cannot search or struggle for the 
other. Moreover, it is almost certain that these animals have too 
imperfect senses and much too low mental powers to appreciate 
each other's beauty or other attractions, or to feel rivalry. 

Hence in these classes or subkingdoms,suchas the Protozoa, 
Coelenterata, Echinodermata, Scolecida, secondary sexual char- 
acters, of the kind which we have to consider, do not occur ; 
and this fact agrees with the belief that such characters in the 
higher classes have been acquired through sexual selection, 
which depends on the will, desire, and choice of either sex. 
Nevertheless some few apparent exceptions occur ; thus, as I 
hear from Dr. Baird, the males of certain Entozoa, or internal 
parasitic worms, differ slightly in color from the females : but 
we have no reason to suppose that such differences havC been 
augmented through sexual selection. Contrivances by ^hich 
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 hermaphroaites or with 
separate sexes, are ornamented with the most brilliant tints or 
are shaded and striped in an elegant manner; vor instae^^ 


many corals and sea-anemones (Actiniae), some jelly-fish (Me- 
dusae, Porpita, etc.), some Planariae, many star-fishes, Echini, 
Ascidians, etc. ; but we may conclude firom the reasons al- 
ready indicated, namely, the union of the two sexes in some 
of these animals, the permanently affixed condition of others, 
and the low mental powers of all, that such colors do not serve 
as a sexual attraction, and have not been acquired through 
sexual selection. It should be borne in mind that in no case 
have we sufficient evidence that colors have been thus acquired, 
except where one sex is much more brilliantly or conspicu- 
ously colored than the other, and where there is no difference 
in habits between the sexes sufficient to account for their dif- 
ferent colors. But the evidence is rendered as complete as it 
can ever be, only when the more ornamented individuals, 
almost always the males, voluntarily display their attractions 
before the other sex ; for we cannot believe that such display 
is useless, and if it be advantageous, sexual selection will al- 
most inevitably follow. We may, however, extend this con- 
clusion to both sexes, when colored alike, if their colors are 
plainly analogous to those of one sex alone in certain other 
species of the same group. 

How, then, are we to account for the beautiful or even gor- 
geous colors of many animals in the lowest classes ? It appears 
doubtful whether such colors often serve as a protection ; but 
that we may easily err on this head will be admitted by every- 
one who reads Mr. Wallace's excellent essay on this subject. 
It would not, for instance, at first occur to any one that the 
transparency of the 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 colors, 
we can hardly doubt that they thus escape the notice of pelagic 
birds and other enemies. M. Giard is also convinced ^ that 
the bright tints of certain sponges and ascidians serve as a pro- 
tection. Conspicuous colors 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 nat- 
ure or the minutestructureof their tissues, independently of any 

» " Archives de Zoolpg, Expcr." Qgt, 1872, p. s6> 

280 THE DESCENT OF MAJV. [part it 

benefit thus derived. Hardly any color is finer than that of 
arterial blood ; but there is no reason to suppose that the color 
of the blood is in itself any advantage; and, though it adds to 
the beauty of the maiden's cheek, no one will pretend that it 
has been acquired for this purpose. So again with many ani- 
mals, especially the lower ones, the bile is richly colored ; thus, 
as I am informed by Mr. Hancock, the extreme beauty of the 
Eolidoe (naked sea-slugs) is chiefly due to the biliary glands 
being seen through the translucent integuments — this beauty 
being probably of no service to these animals. The tints of the 
decaying leaves in an American forest are described by everyone 
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 re- 
cently formed by chemists, and which exhibit the most splendid 
colors, it would have been a strange fact if substances similiarly 
colored had not often originated, independently of any useful 
end thus gained, in the complex laboratory of living organisms. 

The Subkijigdom of the Molliisca. — Throughout this great 
division of the animal kingdom, as far as I can discover, sec- 
ondary 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 (constitut- 
ing th9 Molluscoida of some authors), for most of these animals 
are permanently affixed to a support or have their sexes united 
in the same individual. In the Lamellibranchiata, or bivalve 
shells, hermaphroditism is not rare. In the next higher class 
of the Gasteropoda, or univalve shells, the sexes are either 
united or separate. But in the latter case the males never 
possess special organs for finding, securing, or charming the 
females, or for fighting with other males. As I am informed 
by Mr. Gwyn Jeffreys, the sole external difference between the 
sexes consists in the shell sometimes differing a little in form ; 
for instance, the shell of the male periwinkle {Littorina lit- 
tored) istnarrower and has a more elongated spire than that of 
the femaie. 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 fur- 
nished with imperfect eyes, do not appear to be endowed with 
sufficient mental powers for tke members of the same sex to 
druggie together in rivalry, and thus to acquire secondary" 
Sexual characters. Nevertheless, with the pulmonifcrous gas- 


teroj^ods, or land-snails, the pairing is preceded by courtship ; 
foT these animals, though hermaphrodites, are compelled by 
iheir structure to pair together. Agassiz remarks,'-^ '' Qui- 
conque a eu 1' occasion d' observer les amours des lima^ons, ne 
saurait mettre en doute la seduction deployee dans les mouve- 
mcnts et les allures qui preparent et accomplissent le double 
erfibrassement de ces hermaphrodites." These animals ap 
pear also susceptible of some degree of permanent attachment ; 
an accurate observer, Mr. Lonsdale, informs me that he placed 
a pair of land-snails {Helix pomatia), one of which was 
weakly, into a small and ill-provided garden. After a short 
time the strong and healthy individual disappeared, and was 
traced by its track of slime over a wall into an adjoining well- 
stocked garden. Mr. Lonsdale concluded that it had deserted 
its sickly mate ; but after an absence of twenty-four hours it 
returned, and apparently communicated the result of its suc- 
cessful exploration, for both then started along the same track 
and disappeared over the wall. 

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 everyone who has 
watched their artful endeavors to escape from an enemy. ^ Cer- 
tain Cephalopoda, however, are characterized by one extraor- 
dinary sexual character, namely, that the male element collects 
within one of the arms, or tentacles, which is then cast off, and, 
clinging by its sucking-discs to the female, lives for a time an 
independent life. So completely does the cast-off arm resemble 
a separate animal, that it was described by Cuvier as a parasitic 
worm under the name of Hectocotyle. But this marvellous 
structure may be classed as a primary rather than as a second- 
ary sexual character. 

Although with the Mollusca sexual selection does not seem 
to have come into play, yet many univalve and bivalve shells, 
such as volutes, cones, scallops, etc., are beautifully colored 
and shaped. The colors do not appear in most cases to be of 
any use as a protection ; they are probably the direct result, 
as in the lowest classes, of the nalnie of the tissues ; the pat- 
terns and the sculpture of the shell depending on its manner of 

' "De I'Espfece et de la Class." etc., 1869, have given in my *' Journal of Researches." 
p. 106. 1845, P- 7' 

• See, for instance, the account which I 

282 THE DESCENT OF MAN, [part a 

growth. The amount of light seems to be influential to a cer- 
tain extent ; for although, as repeatedly stated by Mr. Gwyn 
Jeffreys, tlie shells of some species living at a profound depth 
are brightly colored, yet we generally see the lower surfaces, as 
well as the parts covered by the mantle, less highly colored 
than the upper and exi)osed surfaces. "* In some cases, as with 
shells living among corals or brightly tinted sea-weeds, the 
bright colors may serve as a protection.^ But that many of the 
nudi branch moUusca, or sea-slugs, are as beautifully colored as 
any shells, may be seen in Messrs. Alder and Hancock's mag- 
nificent work ; and, from information kindly given me by Mr. 
Hancock, it seems extremely doubtful whether these colors 
usually serve as a protection. With some species this may be 
the case, as with one kind which lives on the green leaves of 
algae, and is itself bright-green. But many brightly colored, 
white, or otherwise conspicuous species do not seek conceal- 
ment ; while again some equally conspicuous species, as well as 
other dull-colored kinds, live under stones and in dark recesses. 
So that with these nudibranch molluscs, color 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 organized creatures this is extremely im- 
probable. Nor is it at all obvious how the offspring from the 
more beautiful pairs of hermaphrodites would have any advan- 
tage over the offspring of the less beautiful, so as to increase in 
number, unless indeed vigor and beauty generally coincided. 
We have not here the case of a number of males becoming 
mature before the females, with the more beautiful males se- 
lected by the more vigorous females. If, indeed, brilliant col- 
ors were beneficial to an hermaphrodite animal in relation to 
its general habits of life, the more brightly tinted individuals 
would succeed best and v/ould increase in number ; but this 
would be a case of natural and not of sexual selection. 

Subkingdom of the Vennes : Class, An?ieHda {or Sea- 

« I have given (" Geolog. Observations on ^ Dr. Morse has lately discussed this sub- 
Volcanic Islands," 1844, p. 53) a curious in- ject in his paper on the Adaptive Coloration 
stanceof the influence of light on the colors of of MoUusca. "Proceedings of the Boston 
a frondescent incrustation, deposited by the Society oi Natural History," vol. xiv., April, 
surf on the coast-rocks of Ascension, and 1871. 
fermcd by the solution of tritiirated sea-shell§. 


worttis). — In this class, although the sexes, when separate, 
sometimes differ from each other in characters of such impor- 
tance that they have been placed under distinct genera or even 
families, yet the differences do not seem of the kind which can 
be safely attributed to sexual selection. These animals are 
often beautifully colored, but as the sexes do not differ in this 
respect, we are but little concerned with them. Even the 
Nemertians, though so lowly organized, ''vie in beauty and 
variety of coloring with any other group in the invertebrate 
series ; ' ' yet Dr. Mcintosh ^ cannot discover that these colors 
are of any service. The sedentary annelids become duller- 
colored, according to M. Quatrefages,"^ after the period of re- 
production ; 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. 

Subkingdo77i of the Arthropoda : Class, Crustacea. — In this 
great class we first meet with undoubted secondary sexual 
characters, often developed in a remarkable manner. Unfort- 
unately the habits of crustaceans are very imperfectly known, 
and we cannot explain the uses of many structures peculiar to 
one sex. With the lower parasitic species the males are of 
small size, and they alone are furnished with perfect swimming- 
legs, antennae, and sense-organs ; the females being destitute of 
these organs, with their bodies often consisting of a mere dis- 
torted mass. But these extraordinary differences between the 
two sexes are, no doubt, related to their widely different habits 
of life, and, consequently, do n®t concern us. In various 
crustaceans, belonging to distinct families, the anterior antennae 
arc furnished with peculiar thread-like bodies, which are be- 
lieved 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 prob- 
ably been acquired through sexual selection, by the better pro- 
vided males having been the more successful in finding partners 
and in producing offspring. Fritz Mliller has described a re- 
markable dimorphic species of Tanais, in which the male is 
represented by two distinct forms, which never graduate into 

* See his beautiful monograph on " Krit- d'apr^s Darwin," "Revue Scienliiique}** 
ish Annelids." i)art i. 1873. p. 3. Feb. 1873, p. 866» ' 

' &•« M. Perrier, *' rOrigine de T Homme 




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 chelae, or pincers, which serve to 
hold the female. Fritz Miiller suggests that these differences 
between the two male forms of the same species may have 
originated in certain individuals having varied in the number 
of the smelling-threads, while other individuals varied in the 
shape and size of their che'lae ; so that of the former, those which 
were best able to find the female, and of the latter, those which 
were best able to hold her, have left the greatest number oi 
progeny to inherit their respective advantages.^ 

In some of the lower crustaceans, the right anterior antenna 
a of the male differs greatly in structure 

from the left, the latter resembling in 
its simple tapering joints the antennae 
of the female. In the male the modi- 
fied antenna is either swollen in the 
middle or angularly bent, or con- 
verted (fig. 4) into an elegant, and 
sometimes wonderfully complex, pre- 
hensile organ. 9 It serves, as I hear 
from Sir J. Lubbock, to hold the 
female, and for this same purpose one 
of the two posterior legs {F) on the 
same side of the body is converted 
into a forceps. In another family the 
inferior or posterior antennae are 
** curiously zigzagged" in the males 

In the higher crustaceans the an> 
terior legs are developed into chelae, 
or pincers ; and these are generally 
larger in the male than in the female 

-so much so that the market value of 

Fig. 4. — Labidocera Darwinii 
(from Lubbock), a. Part of right 

anterior antenna of male form- the male ediblc crab (Caucer pa^urus), 

ing a prehensile organ, b. Pos- r~^ c^ -rd /' 

terior pair of thoracic legs of male. aCCOrdmg tO Mr. C. Spcnce BatC, IS 
c. Ditto of female. ^^^ ^-^^^ ^ ^^^^^ ^ ^^^^ ^^ ^^^ fQma\e. 

In many species the chelae are of unequal size on the opposite 

8 "Facts and Arguments for Darwin," 
Eng. translat. 1869, p. 20. See the previous 
discussion on the olfactory ttireads. Sars 
has described a somewhat analogous case (as 
quoted in " Nature," 1870, p. 455) in a Nor- 
wegian crustacean, \!n^ Pontoporeia affinis. 

•See Sir J. Lubbock in "Annals and 

Mag. of Nat. Hist." vol. xi. 1853, pi. i. and 
X. ; and vol. xii. (1853) pi. vii. See also Lub- 
bock in "Transact. Ent. Soc." vol. iv. new 
series, 1856-1858, p. 8. With respect to the 
zigzagged antennae mentioned below, see 
Fritz Miiller, " Facts and Argumeots for 
Darwin," 1869, p. 40, foot-note. 




side of the body, the right-hand one being, as I am informed 
by Mr. Bate, generally, though not invariably, the largest. 
This inequality is also often much greater in the male than in 
the female. The two chelse of the male often differ in struct- 
ure (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 body, and by the inequality being 
much greater in the male than in the female ; and why, when 
they are of equal size, both are often much larger in the male 

Fig. s. — Anterior part of body of Callianassa (from Rlilne-Edwards), showing the un- 
equal and differently constructed 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. — Second leg of male Orchestia 
Tucuratmga (from FriU Miillcr). 

Fig. 7.— Ditto of female. 

than in the female, is not known. As I hear from Mr. Bate, 
the chelcE are sometimes of such length and size that they can- 
not possibly be used for carrying food to the mouth. In the 
males of certain fresh-water prawns (Palaemon) the right leg is 

286 THE DESCENT OF MAN, [part n. 

actually longer than the whole bodyJ^ The great size of the 
one leg wfth its chelai may aid the male in fighting with his 
rivals ; but this will not account for their inequality in the 
female on the opposite sides of the body. In Gelasimus, ac- 
cording to a statement quoted by Milne-Edwards/^ the male 
and the female live in the same burrow, and this shows that 
they pair ; the male closes the mouth of the burrow with one 
of its chelce, which is enormously developed ; so that here it 
indirectly serves as a means of defence. Their main use, how- 
ever, is probably to seize and to secure the female, and this in 
some instances, as with Gammarus, is known to be the case. 
The male of the hermit or soldier crab (^Pagurus) for weeks to- 
gether carries about the shell inhabited by the female. ^^ The 
sexes, however, of the common shore-crab {^Carcinus niceiias). 
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 Miiller 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 development of these hook-like 
processes has probably followed from those females which were 
the most securely held during the act of reproduction having 
left the largest number of offspring. Another Brazilian amphi- 
pod {Orchestta Dar%vi7iii, fig. 8) presents a case of dimorphism, 
like that of Tanais ; for there ar? two male' forms, which differ 
in the structure of their chelae. ^^ As either chela would cer- 
tainly 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 som.e 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 

'0 See a paper by Mr. C. Spence Bate, " "Hist. Nat. des. Crust." torn. ii. 1837, 

with figures, in " Proc. Zool. Soc." 1868, p. p. 50. 

363 ; and on the nomenclature of the genus, '" Mr. C. Spence Bate, Brit. Assoc, 

ibid. p. 585. lam greatly indebted to Mr. "Fourth Report on the Fauna of .South 

Spence Bate for nearly all the above state- Devon." 

ments with respect to the chelae of the higher "3 Fritz Miiller, "Facts and Arguments 

orustagcans, for Darwin," 1869, pp. 35-a§. 




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 

Fig. 8.— Orchestia Darwinii (from Fritz Miiller). showing the differently constructed 
chelae of the two male forms. 

sexes follow different habits of life, and most of the Ento- 
mostraca must be excepted. The chelae of many crustaceans 
are weapons well adapted for fighting. Thus when a Devil- 
crab {Fortunus puder) was seen by a son of Mr. Bate fighting 
with a Carcinus mcenas, the latter was soon thrown on its back| 

288 THE DESCENT OF MAN". [part vl 

and had every limb torn from its body. When several males 
of a Brazilian (iclasimus, 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 Carciniis mccnas into a pan of water, inhabited by a 
female which was paired with a smaller male ; but the latter 
was soon dispossessed. Mr. Bate adds, " if they fought, the 
victory was a bloodless one, for I saw no wounds." Thisi 
same naturalist separated a male sand-skipper (so common on 
our sea-shores), Gammarus inarinus, from its female, both of 
whom were imprisoned in the same vessel with many indi' 
viduals of the same species. The female, when thus divorced, 
soon joined the others. After a time the male was put again 
into the same vessel ; and he then, after swimming about for a 
time, dashed into the crowd, and without any fighting at once 
took away his wife. This fact shows that in the Amphipoda, 
an order low in the scale, the males and females recognize each 
other, and are mutually attached. 

The mental powers of the Crustacea are probably higher 
than at first sight appears probable. Any one who tries to 
catch one of the shore-crabs, so common on tropical coas',s, will 
perceive how wary and alert they are. There is a lar|/e crab 
{Birgus latrd) found on coral islands which makes a thick- 
bed of the picked fibres of th(. cocoa-nut, at the bottom of a 
deep buri'ow. It feeds on the fallen fruit of this tree by tear- 
ing off the husk, fibre by fibre; and it always begins a. 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 prob- 
ably instinctive, so that they would be performed as well by a 
young animal as by an old one. The following case, however, 
can hardly be so considered : A trustworthy naturalist, Mr. 
Gardner,^^ while watching a shore-crab (Gelasimus) making its 
burrow, threw some shells toward the hole. One rolled in, 
and three other shells remained within a few inches of the 
mouth. In about five minutes the crab brought out the shell 
which had fallen in, and carried it away to the distance of a 
foot ; it then saw the three other shells lying near, and, evi- 
dently thinking that they might likewise roll in, carried them 
to the spot where it had laid the first. It would, I think, be 

'< **Travds in the Interior of Brazil," of Researches," p. 463, an account of tbft 
1846^ p. III. I have given, in my " Journal habits of the Birgus. _ .^^^ 


difficult to distinguish this act from one performed by man by 
the aid of reason. 

Mr. Bate does not know of any well-marked case of difference 
of color 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 tried to distinguish by color the sexes of the several 
species which inhabit the Mauritius, but failed, except with 
one species of Squilla, probably 6*. stylifera, the male of which 
is described as being *' of a beautiful bluish green," with some 
of the appendages cherry-red, while the female is clouded with 
brown and gray, ^' with the red about her much less vivid than 
in the male." ^^ In this case we may suspect the agency of 
sexual selection. From M. Bert's observations on Daphnia, 
when placed in a vessel illuminated by a prism, we have reason 
to believe that even the lowest crustaceans can distinguish 
colors. With Saphirina (an oceanic genus of Entomostraca), 
the males are furnished with minute shields or cell-like bodies, 
which exhibit beautiful changing colors ; these are absent in 
the females, and in both sexes of one species. ^^ It would, 
however, be extremely rash to conclude that these curious 
organs serve to attract the females. I am informed by Fritz 
Miiller that :n the female of a Brazilian species of Gelasimus 
the whole body is of a nearly uniform grayish-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 colors are liable to change in 
the course of a fev/ minutes — the white becoming dirty gray or 
even black, the green " losing much of its brilliancy." It de- 
serves especial notice that the males do not acquire their bright 
colors until they become mature. They appear to be much more 
numerous than the females , they differ also in the larger size of 
their chel?e. 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 con- 
siderations it seems probable that the male in this species has be- 
come gayly ornamented in order to attract or excite the female. 

*• Mr, Ch. Fraser, in " Proc. Zoolog. '* Claus, " Die freilebenden Copcpodob' 
Soc." 1869, p. 3. I am inciebted to Mr. Bate 1863, s. 3$ 
for Dr. Power's statement. 


It has just been stated that the male Gelasinius does not ac- 
quire his conspicuous colors until mature and nearly ready to 
breed. This seems a general rule in the whole class in respect 
to the many remarkable structural differences between the sexes. 
We shall hereafter find the same law i)revailing throughout the 
great subkingdom of the Vertebrata ; and in all cases it is em- 
inently 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, 
which are very differently constructed from those of the female \ 
while young, his claspers resemble those of the female. 

Class, Arachnida (Spiders). — The sexes do not generally 
differ much in color, but the males are often darker than the 
females, as may be seen in Mr. Blackwall's magnificent work.^^ 
In some species, however, the difference is conspicuous ; thus 
the female of Sparassus s?naragdulus is dullish green, while the 
adult male has the abdomen of a fine yellow, with three longi- 
tudinal 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 be- 
long ; but Mr. Blackwall thinks that, as a general rule, it is 
the male ; and Canestrini '^^ remarks that in certain genera the 
males can be specifically distinguished with ease, but the 
females with great difficulty. I am informed by Mr. Blackwall 
that the sexes while young usually resemble each other ; and 
both often undergo great changes in color during their succes- 
sive moults, before arriving at maturity. In other cases the 
male alone appears to change color. Thus the male of the 
above bright-colored Sparassus at first resembles the female, 
and acquires his peculiar tints only when nearly adult. Spiders 
are possessed of acute senses, and exhibit much intelligence ; 
as is well known, the females often show the strongest affec- 
tion for their eggs, which they carry about enveloped in a 
silken web. The males search eagerly for the females, and 
have been seen by Canestrini and others to fight for ^^ossession 
of them. This same author says that the unioi., ^{ the two 

-^ "Facts and Arguments," etc., p. 79. valuable essay on the " Caratteri sessuali 
** "A History of the Spiders of Great secondarii degli Arachnidi," in the "Atti 
Britain," 1861-64. For the following facts, della Soc. Veneto Trentina di So. Nat. Pa- 
see pp. 77, 88, 102. dova," vol. i. Fasc. 3, 1873. 
^' This autlior has recently published a 


sexes has been observed in about twenty species ; and he as- 
serts positively that the female rejects some of the males who 
court her, threatens them with open mandibles, and at last, 
after long hesitation, accepts the chosen one. From these 
several considerations we may admit with some confidence 
that the well-marked differences in color between the sexes of 
certain species are the results of sexual selection ; though we 
have not here the best kind of evidence — the display by the 
male of his ornaments. From the extreme variability of color 
in the male of some species, for instance of Theridion lineatuniy 
it would appear that these sexual characters of the males have 
not as yet become well fixed. Canestrini draws the same con- 
clusion from the fact that the males of certain species present 
two forms, differing from each other in the size and length of 
their jaws ; and this reminds us of the above cases of dimorphic 

The male is generally much smaller than the female, some- 
times to an extraordinary degree,^ and he is forced to be ex- 
tremely 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 hor- 
ror and indignation." 21 The Rev. O: P. Cambridge'-*^ ac- 
counts in the following manner for the extreme smallness of the 
male in the genus Nephila : *' M. Vinson gives a graphic account 
of the agile way in which the diminutive male escapes from 
the ferocity of the female, by gliding about and playing hide 
and seek over her body and along her gigantic limbs : in such 
a pursuit it is evident that the chances of escape would be in 
fa\or 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." 

m hfieira mgt a. In this species, as I may counts. 

adJ, the male is testaceous and the female "' Kirby and Spence. "Introduction to 
black, with l^gs banded with red. Other Entomology," vol. i. 18 18, p. 280. 
erio more striking; cases of iaeauality in size "a •• Proc. Zoolog. Soc." 1871, p 6«i, 

292 THE DESCENT OF MAiV. [part il 

Wcstring has made the interesting discovery that the males 
of several species of Theridion ^ have the power of making a 
stridiilating sound, while the females are mute. The apparatus 
consists of a serrated ridge at the base of the abdomen, against 
which the hard hinder part of the thorax is rubbed ; and of 
this structure not a trace can be detected in the females. It 
deserves notice that several writers, including the well-known 
arachnologist, Walckenaer, have declared that spiders are at- 
tracted by music. 2^ From the analogy of the Orthoptera and 
Homoptera, to be described in the next chapter, we may feel 
almost sure that the stridulation serves, as Westring also be- 
lieves, to call or to excite the female ; and this is the first case 
known to me in the ascending scale of the animal kingdom of 
sounds emitted for this purpose.^ 

Class, Myriapoda. — In neither of the two orders in this class, 
the millipedes and centipedes, can I find any well-marked in- 
stances of such sexual differences as more particularly concern 
us. In Glomeris limbata, however, and perhaps in some few 
other species, the males differ slightly in color from the fe- 
males ; but this Glomeris is a highly variable species. In the 
males of the Diplopoda, the legs belonging either to one of the 
anterior or of the posterior segments of the body are modified 
into prehensile hooks which serve to secure the female. In 
some species of 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 circum- 
stance that it is the female in Lithobius which is furnished 
with prehensile appendages at the extremity of her body for 
holding the male.^ 

53 Theridion (Asagena, Sund.) serra- '^ Kilgendorf, however, has lately called 

tides, i,-punctatum et guttatum ; see attention to an analogous structure in some 

Westring, in Kroyer, " Naturhist. Tids- of the higher crustaceans, which seems 

krift " vol. iv. 1842-43, p. 349; and vol. ii. adapted to produce sound ; see " Zoological 

1846-49. p. 342. See also, for other species, Record," 1869, p. 603. 

"Araneae Suecicse," p. 184. ^® Walckenaer et P. Gervais " Hist. Nat 

24 Dr. H. H. van Zouteveen, in his Dutch des Insectes: Aptere<>," torn. iv. 1847, pp- 

translation of this work (vol. i. p. 444). ha5 17, 19, 68. 
collected several cases. 

5HAP. X.J iNs/icrs, 293 



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 — Thysap'ira — Diptera — Hemip- 
tera — Homoplera, musical powers possessed l)y the males alone — Or- 
thoptera, musical instruments of the males, much diversified in struct- 
ure ; pugnacity ; colors — Neuroptera, sexual differences in color — • 
Hymenoptera, pugnacity and colors — Coleoptera, colors ; furnislied 
with great horns, apparently as an ornament j battles ; stridulating 
organs generally common to both sexes. 

In the immense class of insects the sexes sometimes differ ih 
their locomotive-organs, and often in their sense-organs, as in 
the pectinated and beautifully plumose antennce of the males of 
many species. In Chloeon, one of the Ephemerae, the male 
has great pillared eyes, of which the female is entirely desti- 
tute.^ The ocelli are absent in the females of certain insects, 
as in the Mutillidae ; and here the females are likewise wingless. 
But we are chiefly concerned with structures by which one 
male is enabled to conquer another, either in battle or court- 
ship, 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 aston- 
ishing," as Mr. B. D. Walsh ^ has remarked, " how many dif- 
ferent organs are worked in by nature for the seemingly insig- 
nificant object of enabhng the male to grasp the female firmly." 
The mandibles or jaws are sometimes used for this purpose; 
tlius the male Corydalis cornutus (a neuropterous insect in 
some degree allied to the Dragon-flies, etc.) has immense 
curved jaws, many times longer than those of the female ; and 

' Sir J. Lubbock, "Transact. Linnean tlils can hardly be the case, we may infer 
Soc."' vol. XXV. 1866, p. 484. With respect from the many recorded cases (see, for in- 
to the Mutillidse see Westwood, "Modern stance, Bronn, " Geschiclite der Natnr," B. 
Class, of Insects," vol. ii. p. 213. ii. 1843, s. 164; and Westwood, "Transact. 

"These organs in the male often differ in Ent. Soc." vol. iii. 1842, p. 195) of distinct 

closely allied species, and afford excellent species having been observed in imion. Mr. 

specific characters. Hnt their importance, MacLachlan informs nie (vide '' Stett. Ent. 

from a fnnctional point of view, as Mr. R. Zsituns;," 1867, s. its) that when several 

MacLachlan has remarked to me, has prob- species otPhryganidx, which present strong- 

nbly been overrated. It has been sups;csted ly proncnniccd diffoiences of this kind, were 

that slight differences in these organs would confined together by Dr. Aus?. Meyer, they 

sufficf to prevent the intercrossing of well- cou/>led, and one pair nroduced fertile ova. 
hiarked varieties or incipient species, and ^ "The Practical Entomologist," Phil^« 

Would thus ^d iu tb«ir development. That delphia, vol. ii. May, 1867, p. 8§. 



[part h, 

they are smooth instead of being toothed, so that he is thus en- 
abled to seize her without injury.'* One of the stag-beetles of 
North America {Lticanus elaphtis) uses his jaws, which are 
much larger than those of the fciiiale, for the same purpose, 
but probably likewise for fighting. In one of the sand-wasi>s 
{Atnmophild) the jaws in the two sexes are closely alike, but 
are used for widely different purposes : the males, as Prof. 
Westwood observes, ^* are exceedingly ardent, seizing their 
partners round the neck with their sickle -shaped jaws;"* 
while the females use their organs for burrowing in sand-banks 
and making their nests. 

The tarsi of the front legs are 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 fe- 
male. It is a much more un- 
usual circumstance that the female 
of some water-beetles (Dytiscus) 
have their elytra deeply grooved, 
and in A alius sulcatus thickly 
set with hairs, as an aid to the 
male. The females of some othei 
water -bee ties (Hydroporus) have 
their elytra punctured for the same 
purpose.^ In the male of Crabro 
cribrarius (fig. 9), it is the tibii 
which is dilated into a broad horny 
plate, with minute membraneous* 
dots, giving to it a singular ap- 
pearance like that of a riddle.' Ip 
p /- V -u • TT the male of Penthe (a geninp o* 

Fig. 9. — Crabro cribranus. Upper ^. , „ . . 

ggure, male; lower figure, female. beCtles) a fCW of the middle JO^H^f 

of the antennae are dilated and .''it- 
nished on the inferior surface with cushions of hair, exactly 

< Mr. Walsh, ibid, p. 107. 

^ " Modern Classification of Insects,*' vol. 
ii. 1840, pp. 205, 206. Mr. Walsh, who 
called my attention to the double use of the 
jaws, says that he has repeatedly observed 
this fact. 

* We have here a curious and inexplicable 
case of dimorphism, for some of the females 
of four European species of Dytiscus, and 
of certain species of Hydroporus, have their 
elytra soiooth ; and aQ intermediate jprada- 

tions between ihe sulcated or punctured ar ^ 
the quite smooth elytra have been observed 
See Dr. H. Schaum, as quoted in the 'Zo- 
ologist," vol. v.-vi. 1847-48, p. 1896. Also 
Kirby and Spence, " Introduction to Ento- 
mology," vol. iii. 1826, p. 305. 

^ Westwood, "Modem Class." vol. ii. p. 
193. The following statement about Penthe, 
and others in inverted commas, are taken 
frnin Mr. Walsh, " Practi''.al. Entomologist,'* 
Philadelphia voiu ii. 9. 88. 

CHAP. X.) 



iike those on the tarsi of the Carabidae, '' 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 eml)race the 
neck of the female." Lastly, in the males of 
raany insects, the legs are furnished with pecu- 
liar spines, knobs or spurs ; or the whole leg is 
bowed or thickened ; but this is by no means 
'>nvariably a sexual character ; or one pair or 
all three pairs 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, unique as far as 
known to Mr. Wollaston, of the head of the fe- 
male being much broader and larger, though in a ^-» 
variable degree, than that of the male. Any num- 
ber of such cases could be given. They abound 
in the Lepidoptera : one of the most extraordi- 
nary is that certain male butterflies have their 
forelegs more or less atrophied, with the tibiae 
and tarsi reduced to mere rudimentary knobs. 
The wings, also, in the two sexes often diffe, in 
neuration,^^ and sometimes considerably in out- 
line, as in the Aricoris epitus, which v/as shown 
to me in the British Museum by Mr. A. Butler. 
The males of certain South American butterflies 
have tufts of hair on the margins of the wings, 
and horny excrescences on the discs of the pos- 
terior pair.^^ In several British butterflies, as 
shown by Mr. Wonfor, the males alone are in 
parts clothed with peculiar scales. 

The use of the bright light of the female glow-worm has 
been subject to much discussion. The male is feel)ly lumin- 
ous, as are the larvae and even the eggs. It has been sup- 

8 Kirby and Spence, " Introduct." etc. Shuckard, " Fossorial Hymenop." 1837, pp. 

vol. iii. pp. 3^2-336. _ 39-43^ differ in neuration accenrlng to sex. 

" " Insecta Maderensia," 1834, p. 20. " H. W. Kates, in "Journal of Proc. 

*o E. Doubleday, "Annals and Mag. of Linn. Soc." vol. vi. 1862, p. 74. Mr. Won- 

Nat. Hist." vol. i. 1848, p. 379 I may add for's observations are quoted in " Popular 

(hat the win»t w certain Hynienoptera (see Science Review," i868, p. 343. 

Fig. id.— Taph- 
roderes distortus 
(much enlarged). 
Upper figure, 
male ; lower figure, 

29^3 THE DESCEN7' OE MAN". [part ii 

j^osed ])y some autliors that the light serves to frighten away 
enemies, and by others to guide the male to the female. At 
last, Mr. 13elt '^ appears to have solved the difficulty: he finds 
that all the Lampyridoe which he has tried are highly dis- 
tasteful to insectivorous mammals and birds. Hence it is in 
accordance with Mr. Bates's 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 
believes that the luminous species profit by being at once 
recognized as unpalatable. It is probable that the same ex- 
planation may be extended to the Elaters, both sexes of which 
are highly luminous. It is not known wh.y the wings of the fe- 
male glow-worm have not been developed ; but in her ])resent 
state she closely reseml)les a larva, and as larvie are so largely 
preyed on by many animals, we can understand why she has 
been rendered so much more luminous and conspicuous than 
the male ; and why the larvae themselves are likewise luminous. 
Difference in Size between the Sexes. — With insects of all 
kinds the males are commonly smaller than the females ; and 
this difference can often be detected even in the larval state. 
So considerable is the difference between the male and female 
cocoons of the silk-moth {Bonihyx 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 enor- 
mous 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 attend- 
ing to the development of the caterpillars oi Bomhyx cyfithia and 
yamamai, and especially to that of some dwarfed caterpillars 
reared from a second brood on unnatural food, '' that in pro- 
portion as the individual moth is finer, so is the time required 
for its metamorphosis longer ; and for this reason the female, 
which is the larger and heavier insect, from having to carry 
her numerous eggs, v/ill be preceded by the male, which is 
smaller and has less to mature. ' ' ^^ Now, as most insects are 
short-lived, and as they are exposed to many dangers, it would 
manifestly be advantageous to the female to be impregnated as 
soon as possible. This end would be gained by the males being 
first matured in large numbers ready for the advent of the 

5' "The Naturalist in Nicaragua," 1874, ^^ Robinet, "Vers k Soie," 1848, p. 207. 

pp' 316-320. On the phosphorescence of the ** "Transact. EnL Soc." 3d series, voL V. 

eggs, see " Annals and Mag. of Nat. Hist." p. 486. 
1871," Nov., p. 37a. 

CHAP, x.] IiVSECTS. 297 

females; and this again would naturally follow, as Mr. A. R. 
Wailace has remarked /•'* through natural selection ; for the 
smaller males would be first matured, and thus would procreate 
a large number of offspring which would inherit the reduced 
size of their male parents, while the larger males, from being 
matured later, would leave fewer offspring. 

There are, however, exceptions to the rule of male insects 
being smaller than the females, and some of these exceptions 
are intelligible. Size and strength would be an advantage to 
the males which fight for the possession of the females ; and in 
these cases, as with the stag-beetle (Lucanus), the males are 
larger than the females. There are, however, other beetles 
which are not known to fight together, of which the males 
exceed the females in size, and the meaning of this fact is not 
known ; but in some of these cases, as with the huge Dynastes 
and Megasoraa, 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 (Libellulidae) are sometimes sensibly 
larger, and never smaller, than the females ; ^^ and, as Mr. Mac- 
Lachlan believes, they do not generally pair with the females 
until a week or fortnight has elapsed, and until they have 
assumed their proper masculine colors. But the most curious 
case, showing on what complex and easily overlooked relations 
so trifling a character as difference in size between the sexes 
may depend, is that of the aculeate Hymenoptera ; for Mr. F. 
Smith informs me that throughout nearly the whole of this large 
group, the males, in accordance with the general rule, are 
smaller than the females, and emerge about a week before them ; 
but among the Bees, the males of Apis mellifica, Anthidimn 
vianicatum, and Anthophora acervoriim, and among the Fos- 
sores, the males of the Methoca ichneiwioiiides are larger than 
the females. The explanation of this anomaly is that a mar- 
riage flight is absolutely necessary with these species, and the 
male requires great strength and size in order to carry the 
female through the air. Increased size has here been acquired 
in opposition to the usual relation between size and the 
period of development, for the males though larger, emerge 
before the smaller females. 

** ''Journal of Proc Ent. Soc." Feb. 4, size of the sexes, see Kirby and Spence, 
1867. p. Ixxi. ibid. vol. iii. p. 300 ; on the duration of life 

-" For this and other statements on the in insects, see p. 344. 

298 TkE DESCENT OF MAN. [part it 

We will now review the several Orders, selecting such facts 
as more j)articiilarly concern us. The Lepidoptcra (Butterflies 
and Moths) will be retained for a separate chapter. 

Order, Thysanura. — The members of this lowly organized 
order are wingless, dull-colored, minute insects, with ugly, 
almost misshapen heads and bodies. Their sexes do not differ ; 
but they are interesting as showing us that the males j)ay sed- 
ulous court to the females even low down in the animal scale. 
Sir J. Lubbock ^^ says : '* It is very amusing to see these little 
creatures {S7nynthurus 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 back- 
ward and forward like two playful lambs. Then the female pre- 
tends to run away and the male runs after her with a qreer 
appearance of anger, gets in front and stands facing her agau. ^ 
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, Diptera (Flies). — The sexes differ little in color. The 
greatest difference, known to Mr. F. Walker, is in the genus 
Bibio, in which the males are blackish or quite black, and the 
females obscure brownish-orange. The genus 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 color, edged 
with black, with a pale central stripe, and as these insects have 
altogether a very elegant appearance, it is perhaps more prob- 
able that they serve as ornaments. That the males of some 
Diptera fight together is certain ; for Prof. Westwood ^^ has 
several times seen this with the Tipulse. The males of other 
Diptera apparently try to win the females by their music : H. 
Miiller ^ watched for some time two males of an Eristalis court- 
ing a female ; they hovered above her, and flew from side to 
side, making a high humming noise at the same time. Gnats 

I'' See "The Transactions of the Lin- -i* " Modem Classification of Insects," voL 

aean Society," volume xxvi. 1868, page ii. 1840, p. 526. 

296. 2" Anwendung, etc., '' Verh. d. n. V. 

*8 "The Malay Archipelago," vol. ii. 1869, Jahrg." xxix. p. 80. Mayer, in "America* 

p.'3i3« Naturalist," 1874, p. 236, ^ 


and mosquitoes (Culicidae) also seem to attract each other by 
humming ; 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 insects, in accordance with their highly developed 
nervous system. ^^ 

Order, Hemiptera (Field-Bugs). — Mr. J. W. Douglas, who 
has particularly attended to the British species, has kindly given 
me an account of their sexual differences. The males of some 
species are furnished with wings, while the females are wing- 
less ; the sexes differ in the form of their bodies, elytra, antennae, 
and tarsi ; but, as the signification of these differences are un- 
known, they may be here passed over. The females are gener- 
ally 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 color ; but in about six British 
species the male is considerably darker than the female, and 
in about four other species the female is darker than the male. 
Both sexes of some species are beautifully colored ; and as these 
insects emit an extremely nauseous odor, their conspicuous 
colors may serve as a signal that they are unpalatable to insec- 
tivorous animals. In some few cases their colors appear to be 
directly protective ; thus Prof. Hoffmann informs me that he 
could hardly distinguish a small pink and green species from the 
buds on the trunks of lime-trees, which this insect frequv'nts. 

Some species of Reduvidae 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, Reduvius personatus also stridulates. But I 
have no reason to suppose that this is a sexual character, except- 
ing that with non-social insects there seems to be no use for 
sound-producing organs, unless it be as a sexual call. 

Order, Homoptera. — Everyone 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 

"^^ See Mr. B. T, Lowne*s interesting cuHar plaintive note, and that this sound 

vrork, " On the Anatomy of the Hlow-fly, causes other flies to disappear." 

Musca vomitoria," 1870, p. 14. He remarks aa Westwood. " Modem Class, of Ineects," 

\p. 33) that " the captured tUes ui,l«c ajpe« vol. ii. p. 473. ^ 


Xcnarchus says, *' IIa[)py the Cicadas live, since they all have 
voiceless wives." The noise thus made could be i)lainly 
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 Cicadidae usually sing during the day, while 
the Fulgoridse appear to be night-songsters. The sound, 
according to Landois,'-^ is produced by the vibration of the 
lips of the spiracles, which are set into motion by a current 
of air emitted from the tracheae; but this view has lately 
been disputed. Dr. Powell appears to have proved '^ that it 
is produced by the vibration of a membrane, set into action 
by a special muscle. In the living insect, while stridulating, 
this membrane can be seen to vibrate ; and in the dead insect 
the proper sound is heard, if the muscle, when a little dried 
and hardened, is pulled with the point of a pin. In the fe- 
male the whole complex musical apparatus is present, but is 
much less developed than in the male, and is never used for 
producing sound. 

With respect to the object of the music. Dr. Hartman, in 
speaking of the Cicada septemdecim of the United States, says,'^ 
** the drums are now (June 6 and 7, 185 1) heard in all direc- 
tions. This I believe to be the marital summons from the 
males. Standing in thick chestnut sprouts about as high as my 
head, where hundreds wer :) around me, I observed the females 
coming around the drumming males." He adds : " This season 
(August, 1868) a dwarf pear-tree in my garden produced about 
fifty larvae of Cic. pruinosa ; and I several times noticed the 
females to alight near a male while he was uttering his " clanging 
notes.'* Fritz Miiller writes to me from South Brazil that he 
has often listened to a musical contest between two or three males 
of a species with a particularly loud voice, seated at a consider- 
able 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 thrt the 
females not only find them by their sounds, but that, like female 

*' These particulars are taken from West- '5 »» Transact New Zealand Institute," 

wood'i" 'Modem Class, of Insects," vol. iu vol. v. 1873, P" ^^^* 

1840, p. 422. See also, on the Fulgoridse, '* I am indebted to Mr. Walsh r')r bsvi' j 

Kirby and Spence, '' Introduct." vol. ii. p. sent me this extract from a " Jounia! of th.o 

401. Doings of Cicada septemlecur. ' by Ui 

'♦ " Zeitschrift fiir wissenschaft Zoolog." Hartman. 
Bt zvu. 1867, s. 152-158. 




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, while the females 
are pale- colored or obscure. 

Order, Orthoptera (Crickets and Grasshoppers). — The males 
in the three saltatorial families in this Order are remarkable for 
their musical powers, namely, the Achetidae, or crickets, the 
Locustidae, for which there is no equivalent English name, and 
the Acridiidae, or grasshoppers. The stridulation produced by 
some of the Locustidae is so 
loud that it can be heard dur- 
ing the night at the distance 
of a mile ; ^^ and that made 
by certain species is not un- 
musical even to the human 
ear, so that the Indians on 
the Amazons keep them in 
wicker cages. All observers 
agree that the sounds serve 
either to call or excite the 
mute females. With respect 
to the migratory locusts of 
Russia, Korter has given^ an Fig. n.— Oniius campestris (from Lan- 

inft^rfKjHncr c^^e- nf cplprHnn **°'^^- Right-hand figure, under side of part of 

iiikv^iv^oLiiig *^cu5t Kj\. ocic^^LUjii ^ Wing ncrvure, much magmneu, showing the 

by the female of a male, '^.^^h, st. Left-hand figure, upper surface of 

_/, - r L • • wmg-cover, with the projecting, smooth nerv- 

ihe males of this species ure.r, across which the teeth (j/) are scraped. 

{Pachytylus migratorius) 

while coupled with the female stridulate from anger or jealousy 
if approached by other males. The house-cricket when sur- 
prised at night uses its voice to warn its fellows. ^^ In North 
America the Katy-did {Platyphyllum concavu?n, one of the Lo- 
custidae) is described^ as mounting on the upper branches of a 
ti'ee, and in the evening beginning ** his nodsy babble, while 
rival notes issue from the neighboring trees, and the groves re- 
sound with the call of Katy-did- she-did the livelong night." 
Mr. Bates, in speaking of the European field-cricket (one of 

•'Guildine.Trans.Linn. Soc.,vol.xv. 154. " Gilbert White, '•Nat. Hist of Sog* 

^^ I state this on the authority of Koppen, borne," vol. ii. 1825, p. 262. 

•*U-^ber die Heuschrecken in Siidrussland," '" Harris, "lasects of New Eagland^** 

t86o, p. ;;2, for I have in vain endeavored 1842, p. 128. 

•9 procure Korte's work* 



[pAftt It 

the Achetidae), says, *'the male has been observed to place 
himself in the evening at the entrance of his burrow, and strid- 
ulate until a female approaches, when the louder notes are suc- 
ceeded by a more subdued tone, while the successful musician 
caresses with his antennae the mate he has won." ^ Dr. Scud- 
der was able to excite one of these insects to answer him, by 
rubbing on a file with a qui 11.'^ In both sexes a remarkable 
auditory apparatus has been discovered by Von Siebold, situated 
in the front legs.^ 

In the three Families the sounds are differently produced. 
In the males of the Achetidae both wing-covers have the same 
apparatus; and this in the field-cricket {^Gryllus campestris, 
fig. ii) consists, as described by Landois,^^ of from 131 to 138 
sharp, transverse ridges or teeth {st) on the under side of one 
of the nervures of the wing-cover. This toothed nervure is 
rapidly scraped across a projecting, smooth, hard 
nervure (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. 1 2) of the teeth on the under side of the 
nervure of another species of Gryllus, viz., G. 
With respect to the formation of 
these teeth. Dr. Gruber has shown ^ that they 
have been developed by the aid of selection, 
from the minute scales and hairs with which the wings and 
body are covered, and I came to the same conclusion with 
respect to those of the Coleoptera. But Dr. Gruber further 
shows that their development is in part directly due to the 
stimulus from the friction of one wing over the other. 

In the Locustidae the opposite wing-covers differ from each 
other in structure (fig. 13), and the action cannot, as in the 
ast family, be reversed. The left wing, which acts as the 
bow, lies over the right wing, which serves as the fiddle. One 

^ The Naturalist on the Amazons, vol. i. 3* " Zeitschrift fvir Wissenschaft. Zoolog." 
1863, p. 252. Mr. Bates gives a very interest- B. xvii. 1867,8. 117 

Fig. 12.— Teeth donUSticUS 
•li Nervure of Gryl- 
lus domesticus 
(from Landois). 

ing discussion on the gradations in the musi- 
cal apparatus of the three families. See also 
Westwood, Mod. Class, vol. ii. pp. 445 & 453. 

32 " Proc. Boston Soc. of Nat. Hist." vol. 
o. April, 1868. 

^' " Nouveau Manuel d'Anat. Comp." 
(French translat.), t«m. i. 1850, p. 567. 

'5 Westwood, "Modem Class, of Insects," 
vol. i. p. 440. 

3^ " Ueber den Tonapparat der Locus- 
tiden. ein Beitrag zum Darwinismus," 
"Zeitsch. fiir Wissentch. Zoolog." B. xxiL 
1872, p. 100. 

CHAT. X.] 



of the nervures {a) on the under surface of the former is finely- 
serrated, and is scraped across the prominent nervures on the 
upper surface of the opposite or right wing. In our British 
Phasgonura viridissima it appeared to me that the serrated 
nervure is rubbed against the rounded hind-corner of the oppo- 
site wing, the edge of which is thickened, colored brown, and 
very sharp. In the right wing, but not in the left, there is a 
little plate, as transparent as talc, surrounded by nervures, and 

Fia. 13.— Chlorocoelus Xanana (from Bates). a,b. Lobesof opposite wing-overs. 

called the speculum. In Ephippiger viftum, a member of thit. 
game family, we have a curious subordinate modification ; for 
the wing-covers are greatly reduced in size, but "■ the posterior 
part of the pro-thorax is elevated into a kind of dome over the 
wing-covers, and which has probably the effect of increasing 
the sound." ^^ 

We thus see that the musical apparatus is more differentiated 
9r specialized in the Locustidae (which include I believe, the 

»' Westwood. "Modern Class, of Insects^' vol. I *. *sa, 



[part It 

most powerful performers in the Order), than in the Aclietidie, 
in which l)oth wing-covers have the same structure and the 
same function.^ I.andois, however, detected in one of the 
LocustidaD, namely, in Decticus, a short and narrow row of small 
teeth, mere rudiments, on the inferior surface of the right wing- 
cover, which underlies the other and is never used as the bow. 
I observed the same rudimentary structure on the under side of 
the right wing-cover in Phasgoniira viridissima. Hence we 
may infer with confidence that the Locustidae are descended 
from a form in which, as in the existing Achetidai, both wing- 
covers had serrated nervures on the under surface, and could 
be indifferently used as the bow ; but that in the Locustidse 

the two wing-covers gradually 
became differentiated and per- 
fected, on the principle of the 
division of labor, the one to act 
exclusively as the bow, and the 
other as the fiddle. Dr. Gruber 
takes the same view, and has 
shown that rudimentary teeth 
are commonly found on the in- 
ferior surface of the right wing. 
By what steps the more simple 
apparatus in the Achetidoe orig- 
, , inated, we do not know, but it 

Fig. 14.— Hind-leg of Stenobothrus pra- . v -ui -i . ^1 i 1 

torum : r, the stridulating ridge ; lower IS probablC that the basal por- 
figure the teeth fonning the ridge, much ^ |- ^j^^ wing-COVerS OHgi- 

l»ag;nined (from LandoisJ. o o 

nally overlapped each other as 
they do at present ; and that the friction of the nervures pro- 
duced a grating sound, as is now the case with the wing-covers 
of the females.^ A grating sound thus occasionally and acci- 
dentally 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, nam.ely, 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 
preceding FamiUes. The inner surface of the femur (fig. 14, r) 
is furnished with a longitudinal row of minute, elegant, lancet- 
s' Landois, " Zeitsch. f. Wiss. Zoolog." lutn concavum, " when captured, makes a 
B. xvii. 1867, s. 121, 122. feeble grating noise by shuffling her wing- 

39 Mr. Walsh also informs me that he covers together*" 
Vias noticed that the female of the Platyphyl- 

CHAP. X. ' 



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. Harris ^^ 
says that when one of the males begins to play, he first '' bends 
the shank of the hind-leg beneath the thigh, where it is 
lodged in a furrow designed to receive it, and then draws 
the leg briskly up and down. He does not play both fid' 

Fic. 15.— Pneumora (from spectinens in the British Museum). Upper figure, male, 

lower figure, female. 

dies 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 resounding board. In Pneumora (fig. 15), a South African 

*^ Landois. ibid. s. 113. 

" " Insects of New England," 1842, p. 133. 

306 THE DESCENT OF AfAN, (part n. 

geniLS belonging to the same family, we meet with a new and 
icmarkaljle modification; in the males a small notched ridge 
projects obliquely from each side of the abdomen, against 
which the hind femora are rubbed.'^ As the male is furnished 
with wings (the female being wingless), it is remarkable that 
the thighs are not rubbed in the usual manner against the wing- 
covers ; but this may perhaps be accounted for by the unusually 
small size of the hind-legs. I have not been able to examine 
the inner surface of the thighs, which, judging from analogy, 
would be finely serrated. The species of Pneumora have been 
more profoundly modified for the sake of stridulation than any 
other orthopterous insect ; for in the male the whole body has 
been converted into a musical instrument, being distended with 
air, like a great pellucid bladder, so as to increase the reson- 
ance. 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 shown that both 
sexes of Ephippiger 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 sec- 
ondary 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 Locustidae (but not according to Landois in 
Decticus) the females have rudiments of the stnduiatory 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 Achetidae, and 
on the femora of the female Acridiidse. In the Homoptera, 
also, the females have the proper musical apparatus in a func- 
tionless state ; and we shall tiereafter meet in other divisions of 
the animal kingdom Avith many instances of structures proper 
to the male being present in a rudimentary condition in the 

Landois has observed another important fact, namely, that 
in the females of the Acridiidse, 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 

*' WestwQQcU " Mod^ro CUssificatioftj" vqI. i. p. 463. 


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 v/hole organization having undergone 
multifarious 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 Orthoptera and in the 
Homoptera impresses the mind with the high importance of 
these structures to the males, for the sake of calling or alluring 
the females. We need feel no surprise at the amount of modi- 
fication 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-knov/n 
tympanum or stridulating apparatus of the male Locustidae." 
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 Orthop- 

I have but little more to say on the Orthoptera. Some oi 
the species are very pugnacious. When two male field-crickets 
{Gryllus campestris) are confined together, they fight till one 
kills the other ; and the species of Mantis are described as 
manoeuvring with their sword-like front limbs, like hussars with 
their sabres. The Chinese keep these insects in little bamboo 
cages, and match them like game-cocks.'*'^ With respect to 
color, some exotic locusts are beautifully ornamented ; the 
posterior wings being marked with red, blue, and black ; but 
as throughout the Order the sexes rarely differ much in color, 
it is not probable that they owe their bright tints to sexual 
selection. Conspicuous colors may be of use to these insects, 
by giving notice that they are unpalatable. Thus it has been 
observed^ that a bright-colored Indian locust was invariably 

*»Landois has recently found in certain «* "Transact. Ent. Soc." 3d series, vol* 

Orthoptera nidimentary structures closely ii. (" Joum.-\l of Proceedings," p. 117.) 

similar to the sound-producing organs in the ** Wcstwood, "Modern Class, of In- 

Homoptera ; and this is a surprising fact, sects/' vol. i. p. 427 ; for crickets, p. 445. 

See "Zeitschr. fur Wissensch. Zoolog." B. *• Mr. Ch. Home, in "Proc. Eut. Soc'^ 

uii Helt. 3. 1871, p. 348. May 3, 1869, p. xii. 

308 THE DESCENT OF MAN, [part ii. 

rejected when offered to birds and lizards. Some cases, how- 
ever, are known of sexual differences of color in this Order. 
The male of an American cricket ''Ms described as being as 
white as ivory, while the female varies from almost white to 
greenish-yellow or dusky. Mr. Walsh informs me that the 
adult male oi Spcctnun fcmoratum (one of the Phasmidae) " is 
of a shining brownish-yellow color; the adult female being of 
a dull, opaque, cinereous brown ; the young of both sexes being 
green." Lastly, I may mention that the male of one curiouf 
kind of cricket '^ is furnished with *' along membranous append- 
age, which falls over the face like a veil;" but what its use 
may be, is not known. 

Order, Neuroptera. — Little need here be said, except as to 
color. In the Ephemeridse the sexes often differ slightly in 
their obscure tints ; *^ but it is not probable that the males are 
thus rendered a,ttractive to the females. The Libellulidae, or 
dragon-flies, are ornamented with splendid green, blue, yellow, 
and vermilion metallic tints ; and the sexes often differ. Thus, 
as Prof. Westwood remarks,^ the males of some of the 
Agrionidce ''are of a rich blue with black wings, while the 
females are fine green v/ith colorless wings." But in Agrion 
Ramburii these colors are exactly reversed in the two sexes. ^^ 
In the extensive North American genus of Hetaerina, the males 
alone have a beautiful carmine spot at the base of each wing. 
In Anax junms 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 m some other 
genera, the sexes differ but Httle in color. In closely allied 
forms throughout the animal kingdom, similar cases of the sexes 
differing greatly, or very little, or not at all, are of frequent 
occurrence. Although there is so wide a difTerence m color 
between the sexes of many Libelluhdse, it is often difficult to 
say which is the more brilKant ; 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 colors in any case have 
been gained as a protection. Mr. MacLachlan, who has closely 
attended to this family, writes to me that dragon-flies — the 
tyrants of the insect-world — are the least liable of any insect to 

<T The (Ecantkus nivalis. Harris, "In- ** B. D. Walsh, the " Pseudo-neuroptera 

sects of New England," 1842. p. 124. The of Illinois," in " Proc. Ent. Soc. of Phila- 

two sexes of Qi. pellucidus of Europe dif- delphia," 1862, p. 361. 

fer, as I hear from Victor Carus, in nearly *° " Modem Class." vol. ii. p. 37. 

the same manner. " Walsh, ibid. p. 381. I ani indebted to 

'•'* Platyblemnus : Westwood, " Modem this natnralist for the following facts ot 

Class." vol. i. p. 447. Hetaerina, Anax, and Gomphus* 


be attacked by birds or other enemies, and he beheves that 
their bright colors serve as a sexual attraction. Certain dragon- 
fiies apparently are attracted by jjarticular colors. Mr. Patter- 
son observed -'^ that the Agrionidai, of which the males are 
blue, settled in numbers on the blue float of a fishing line, 
while two other species were attracted by shining white colors. 

It is an interesting fact, first noticed by Schelver, that, in 
several genera belonging to two sub-families, the males on first 
emergence from the pupal state are colored exactly like the 
females ; but that their bodies in a short time assume a con- 
spicuous milky-blue tint, owing to the exudation of a kind of 
oil, soluble in ether and alcohol. Mr. MacLachlan beheves 
that in the male oi Libellula depressa this change of color does 
not occur until nearly a fortnight after the metamorphosis, 
when the sexes are ready to pair. 

Certain species of Neurothemis present, according to 
Brauer,^ a curious case of dimorphism, some of the females 
having ordinary wings, while others have them ''very richly 
netted, as in the males of the same species." Brauer ''ex- 
plains the phenomenon on Darwinian principles by the suppo- 
sition 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 s])ecies of Agrion, in which some indi- 
viduals are of an orange color, and these are invariably females. 
This is probably a case of reversion ; for in the true Libellulae, 
when the sexes differ in color, the females are orange or yellow; 
so that, supposing Agrion to be descended from some primor- 
dial form which resembled the typical Libellulae in its sexual 
characters, it would not be surprising that a tendency to vary 
in this manner should occur in the females alone. 

Although many dragon -flies are large, powerful, and fierce 
insects, the males have not been observed by Mr. MacLachlan 
to fight together, excepting, as he believes, in some of the 
smaller species of Agrion. In another group in this Order, 
namely, the Termites, or white ants, both sexes at the time 
of swarming may be seen running about, " the male after the 
female, sometimes two chasing one female, and contending 
with great eagerness who shall win the prize." ^ The Atropos 

•'Trans. Ent. Soc, vol. i.. 1836, p. Ixxxi. 6* Kirby and Spence, " Introduct. to En* 
•* See abstract in the *' Zoological Rec- tomology," vol. ii. 1818, p. 35. 
•td"for 1867, p. 450. 

3IO THR DESCnirr OF MAN', [pakt il 

pulsatorius is said to make a nv>ise with its jaws, which is 
answered by other individuals." ^ 

Order, Hyinerioptera. — 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 pos- 
session of some particular female, who sits an apparently uncon- 
cerned 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 (Ten thredinae) **have been found fighting together, 
with their mandibles locked." As M. Fabre speaks of the 
males of Cerceris striving to obtain a particular female, it may 
be well to bear in mind that insects belonging to this Order 
have the power of recognizing each other after long intervals 
of time, and are deeply attached. For instance, Pierre Huber, 
whose accuracy no one doubts, separated some ants, and when, 
after an interval of four months, they met others which had 
formerly belonged to the same community, they recognized 
and caressed one another with their 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 the general confusion, but they 
soon perceive their mistake, and the one ant soothes the other. ^ 

In this Order slight differences in color, according to sex, are 
common, but conspicuous differences are rare except in the 
family of Bees ; yet both sexes of certain groups are so brill- 
iantly colored — for instance in Chrysis, in which vermilion 
and metallic greens prevail — that we are tempted to attribute 
the result to sexual selection. In the Ichneumonidae, accord- 
ing to Mr. Walsh, ^^ the males are almost universally lighter- 
colored than the females. On the other hand, in the Ten- 
thredinidae the males are generally darker than the females. In 
the Siricidae the sexes frequently differ ; thus the male of 
Sirex juvencus is banded with orange, while the female is dark 
purple; but it is difficult to say which sex is the more orna- 
mented. In Tremex columbce the female is much brighter- 
colored than the male. I am informed by Mr. F. Smith that 
the male ants of several species are black, the females being 

*' Houzeau, " Les Facultes Mentales,** the Entomological Society " for September 

etc., torn. i. p. 104. 7» 1863, p. 169. , ,, 

6« See an interesting article. "The Writ- ^8 p. Hubei, " Recherches sur les Moeun 

fags of Fabre," in " Nat. Hist. Review," des Fourmis," 1810. pp. 150, 165. 

April, 1862, p. 122. *^ •' Proc. Kntomolog. Soc. of Philado* 

•' Sec the "Journal of the Proceedings of phia," 1866, pp. 238-239. 


In the family of Bees, especially in the solitary species, as I 
hear from the same entomologist, the sexes often differ in 
color. The males are generally the brighter, and, in Bombus 
as well as in Apathus, much more variable in color than the 
females. \n Anthophora reiusa the male is of a rich fulvous- 
brown, while the female is quite black ; so are the females of sev- 
eral si)ecies of Xylocopa, the males being bright yellow On the 
other hand, the females of some species, as of Andrcena fulvay 
are much brighter-colored than the males Such dilferences 
in color can hardly be accounted for by the males being de- 
fenceless and thus requiring protection, whik the females are 
well defended by their stings. H. Miiller,^ who has particu- 
larly attended to the habits of bees, attributes these differences 
in color in chief part to sexual selection That bees have a 
keen perception of color is certain He says that the males 
search eagerly and fight for the possession of the females ; and 
he accounts through such contests for the mandibles of the 
males being in certain species larger than those of the females. 
In some cases the males are far more numerous than the fe- 
males, 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 beau- 
tiful females by the males. Consequently, in certain genera 
(Miiller, p. 42), the males of the several species differ much in 
appearance, while the females are almost indistinguishable ; in 
other genera the reverse occurs. H. Miiller believes (p. 82) 
that the colors gained by one sex through sexual selection have 
often been 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 use- 
less. ^^ 

Mutilla Europcea makes a stridulating noise ; and according 

"^ " Anwendung der Darwin'schen Lehre produce males; and will it be pretended 

auf Bienen." Verh. d. n. Jahrg. xxix. that such males would not inherit the char- 

'^ M. Perrier in his article, "La Selection acters of their male grandfathers? To take 
sexuelle d'apres Darwin" (*' Revue Scienti- a case with ordinary animals as nearly paral- 
fique," Feb. 1873, p. 868), without apparently lel as possible : if a female of any white 
having reflected much on the subject, objects quadruped or bird were crossed by a male 
that as the males of social bees are known to of a black breed, and tie male and female 
be produced from unfertilized ova, they offspring were paired together, will it be pre- 
could not transmit new characters to their tended that the grandchildren would not in- 
male offsprinp. This is an extraordinary herit a tendency to blackness from their 
objection. A female bee fertilized by a male grandfather ? The acquirement of new 
male, which preseiUed some character facili- characters by the sterile worker-bees is a 
tating the union of the sexes, or rendering much more difficult case, but I have endeav- 
him more attractive to the female, would lay ored to show in my " Origin of Species" 
eggs which would produce only females ; how these sterile beings are subiected to the 
but these young females would next year power of natural selection. 

312 77//'; n use ['.NT OF MAN. [pakt ii. 

to Goiireau ''^ ])Oth 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 concentric ridges ; but so is the i)rojecting 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 
^.heir humming; and, according to H. Miiller (p. 80), the 
males of some species make a pecuHar singing noise while pur- 
suing the females. 

Order, Coleoptera (Beetles).— Many beetles are colored so as 
to resemble the surfaces which they habitually frequent, and 
they thus escape detection by their enemies. Other species, 
for instance, diamond-beetles, are ornamented with splendid 
colors, which are often arranged in stripes, spots, crosses, and 
other elegant patterns. Such colors can hardly serve directly 
as a protection, except in the case of certain flower-feeding 
species ; but they may serve as a warning or means of recogni- 
tion, on the same principle as the phosphorescence of the glow- 
worm. As with beetles the colors of the two sexes are gener- 
ally 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, Jr., 
exhibit bright colors, though they often have polished coats ; 
but the explanation of their obscurity may be that they gen- 
erally inhabit caves and other obscure stations. 

Some Longicorns, especially certain Prionidse, offer an 
exception to the rule that the sexes of beetles do not differ in 
color. Most of these insects are large and splendidly colored. 
The males in the genus Pyrodes,^ which I saw in Mr. Bates's 

•' Quoted by Westwood, "Modem Class. Rhagium, and the Leptura testacea ; the 

of Insects," vol. ii. p. 214. male of the latter being testaceous, with a 

63 Pyrodes pulcherrimus, in which the black thorax, and the female of a dull red all 

sexes differ conspicuously, has been de- over. These two latter beetles belong to the 

scribed by Mr. Bates in "Transact. Ent. family of Longicorns. Messrs. R. Trimen 

Soc." 1869. p. 50. I will specify the few other and Waterhouse, Jr., inform me of two 

cases in which 1 have heard of a difference Lamellicoms, viz.. a PeritrichiaandTrichius, 

in color between the sexes of beet'es. Kirby the male of the latter being more rbscurely 

and Spence (" Introduct. to Entomology," colored than the female. In Tillus elon' 

voL iii. p. 301) mention a Cantbaris, Meloe, gatus the male is black, apd the female al^ 

CHAP. X.] 



collection, arc generally redder but rather duller than the 
females, the latter being colored of a more or less splendid 
golden-green. On the other hand, in one species the male is 
golden-green, the female being richly tinted with red and 
purple. In the genus Esmeralda the sexes differ so greatly in 
color that they have been ranked as distinct species ; in one 
species both are of a beautiful shining green, but the male has 
a red thorax. On the whole, as far as I could judge, the 
females of those Prionidae in which the sexes differ are colored 

Fig. !<.<— Chalcosoma atlas. Upper figure, male (reduced) ; lower figure, female (tmt. 


more richly than the males, and this does not accord with the 
commop rule in regard to color, when acquired through sexual 

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 quadru- 
peds, such as stags, rhinoceroses, etc., and are wonderful both 
from their size and diversified shapes. Instead of describing 

ways, as it is believed, of a dark blue color, is black, the female (the so-called O. rufif 
with a red thorax. The male, aiso, of Or- coUis) having a rufous thorax. 
sqdacna atra, as I he» fi-om Mr. Walsh, 

(N)— Vol. 3 



[part IL 

FiG. 17.— Copris isidis. (Left-band figures, malesj 

Fig. 18.— Pbanseus iaunus. 

Fig. 19.— Dipelicus canton. 

Fig, 20,— Onthophagus rangifer, enlarged. 


them, I have given figures of the males and females of some 
of the more remarkable forms. (Figs. 16 to 20.) The females 
generally exhibit rudiments of the horns in the form of small 
knobs or ridges ; but some are destitute of even the slightest 
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 m 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. 

In almost all cases the horns are remarkable from their 
excessive variability ; so that a graduated series can be formed 
from the most highly developed males to others so degenerate 
that they can barely be distinguished from the females. Mr. 
Walsh ^^ found that in Phanceus carnifex the horns were thrice 
as long in some males as in others. Mr. Bates, after examin- 
ing above a hundred males of Onthophagus rangifer (fig. 20), 
thought that he had at last discovered a species in which the 
horns did not vary ; but further research proved the contrary. 

The extraordinary size of the horns, and their widely dif- 
ferent structure in closely allied forms, indicate that they have 
been formed for some purpose , but their excessive variability 
in the males of the same species leads to the inference that this 
purpose cannot be of a definite nature. The horns do not 
show marks of friction, as if used for any ordinary work. Some 
authors suppose ^^ that, as the males wander about much more 
than the females, they require horns as a defence against their 
enemies ; but as the horns are often blunt, they do not seem 
well adapted for defence. The most obvious conjecture is that 
they are used by the males for fighting together ; but the 
males have never been observed to fight , nor could Mr. Bates, 
after a careful examination of numerous species, find any suiifi- 
cient 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 Coprid^e, did not find any 

«* " Proc, Entomolog. Soc. of Philadel- «' Kirby and Spence, " Introduci. £liitO- 
phia," 1864, p. 228. molr>g." vol. iii. p. 300. 



[part u 

marked aifference in this respect among well-developed indi- 
viduals. In Lethrus, moreover, a beetle belonging to the 
same great division of the Lamellicorns, the males are known 
to fight, but are not provided with horns, though their mandi- 
bles are much larger than those of the female. 

The conclusion that the horns have been acquired as orna- 
ments is that which best agrees with the fact of their having 
been so immensely, yet not fixedly, developed — as shown by 
♦^^heir 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 Onitisfurcifer (fig. 21) and of some other species 
of the genus are furnished with singular projections on their an- 
terior 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. Al- 
though the males have not even a trace of a 
horn on the upper surface of the body, yet 
the females plainly exhibit a rudiment of a 
single horn on the head (fig. 22, «), and of 
a crest (J?) on the thorax. That the slight 
thoracic crest in the female is a rudiment 
of a projection proper to the male, though 
entirely absent in the male of this particu- 
lar species, is clear : for the female of Bubas bison (a genus 
which comes next to Onitis) has a similar slight crest on the 

Fig. 21. — Onitis furcifer, 
male, viewed from beneath. 

Fig. 22.— Left-hand figure, male of Onitis furcifer, viewed laterally. Right-hand figurBj 
female, a. Rudiment of cephalic horn. b. Trace of thoracic horn or crest. 

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) ®n the head of the female Onitis furcifer, as 
well as on the head of the females of two or three allied 
species, is a rudimentary representative of the cephalic horn, 
which is common to the males of so many Lamellicorn 
beetles, as in PhancTeiis (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 
fanvily. We may reasonably suspect that the males originally bore 
horns and transferred them to the females in a rudimentary con- 
dition, as in so many other Lamellicorns. Why the males subse- 
quently lost their horns, we know not ; but this may have been 
caused through the principle of compensation, owing to the de- 
velopment of the large horns and projections on the lower sur- 
face ; and as these are confined to the males, the rudiments of the 
upper horns on the females would not have been thus obliterated. 
The cases hitherto given refer to the Lamellicorns, but the 
males of some few other beetles, belonging to two widely dis- 
tinct groups, namely, the Curcuhonidae and Staphylinidse, are 
furnished with horns — in the former on the lower surface of the 
body,^ in the latter on the upper surface of the head and thorax. 
In the Staphylinidae the horns of the males are extraordinarily 
variable in the same species, just as we have seen with the 
Lamellicorns. In Siagonium we have a case of dimorphism, 
for the males can be divided into two sets, differing greatly in 
the size of their bodies and in the development of their horns, 
without intermediate gradations. In a species of Bledius (fig. 


Fig. 23.— Bledius taurus, magnified. Left-harid figure, male; right-hand figure, female. 

23), also belonging to the. Staphylinidae, Prof. Westwood 
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 rudi mental ; and others, in 
which the thoracic horn is much shorter, while the protu- 
berances on the head are long." ^ Here we apparently have 

»• Kirby and Spence, " Introduce. Ento- British Museum I noticed one male sped* 

molog.'' vol. iii. p. 329. men of Siagonium in an intermediate condi* 

•■' " Modern Classification of Insects," tion, so that the dimorphism is not strict. 
VoL i. p. 172 : Siagonium, p. 172. In the 

31 8 THE DESCENT OF MA AT. [part u, 

a case of compensation, which throws light on that just 
given of the supposed loss of the upper horns by the males oi 

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 
(JLucanus cervus) the males of which emerge from the pupal 
state about a week before the other sex, so that several may 
often be seen pursuing the same female. At this season they 
engage in fierce conflicts. When Mr. A. H. Davis ^^ inclosed 
two males with one female in. a box, the larger male severely 
pinched the smaller one, until he resigned his pretensions. A 
friend informs me that when a boy he often put the males 
together to see them fight, and he noticed that they were much 
bolder and fiercer than the females, as with the higher animals. 
The males would seize hold of his finger, if held in front of 
them, but not so the females, although they have stronger jaws. 
The males of many of the Lucanidae, as well as of the above- 
mentioned Leptorhynchus, are larger and more powerful insects 
than the females. The two sexes of Lethrus cephalotes (one of 
the Lamelli corns) inhabit the same burrow, and the male has 
larger mandibles than the female. If, during the breeding- 
season, a strange male attempts to enter the burrow, he is 
attacked ; the female does not remain passive, but closes the 
mouth of the burrow, and encourages her mate by continually 
pushing him on from behind ; and the battle lasts until the 
aggressor is killed or runs away.'*'^ The two sexes of another 
Lamellicorn beetle, the Ateuchus cicatricosus, live in pairs, 
and seem much attached to each other ; the male excites the 
female to roll the balls of dung in which the ova are de- 
posited ; and if she is removed, he becomes much agitated. 

«8 "The Malay Archipelago," vol. ii. species, Kirby and Spence, ibid. vol. iii. p. 

1869, p. 276. Riley, Sixth "Report on In- 314 ; and Westwood, ibid. vol. i. p. 187. 

sects of Missouri," 1874, p. 115. ''° Quoted from Fischer, in "Diet. CUwSt 

«» "Entomological Magazine," vol. i. d'Hist. Nav" torn. x. p. 324. 
{6331 p. 83, See also on the conflicts of this 

CHAP. X.] 



If the male is removed the female ceases all work, and, as M. 
Brulerie ''^ believes, would remain on the s?me spot until she died. 

The great mandibles of the male 
Lucanidse are extremely variable lx)th 
in size and structure, and in this re- 
spect resemble the horns on the head 
and thorax of many male Lamelli- 
corns and Staphylinidse. A perfect 
series can be formed from the best- 
provided to the worst-provided or de- 
generate males. Although the mandi- 
bles of the common stag-beetle, and 
probably of many other species, are 
used as efficient weapons for fighting, 
it is doubtful whether their great size 
can thus be accounted for. We have 
seen that they are used by the Lucanus 
elaphus of North America for seizing 
the female. As they are so conspic- 
uous and so elegantly branched, and 
as owing to their great length they are 
not well adapted for pinching, the sus- 
picion has crossed my mind that they 
may in addition serve as an ornament, 
like the horns on the head and thorax 
of the various species above described. 
The male Chiasognathus grantii of 
South Chile — a splendid beetle belong- 
ing to the same family — has enormous- 
ly developed mandibles (fig. 24) ; he 
is bold and pugnacious ; when threat- 
ened 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 JJwerlfgure^^rmaii;^"''' '"^'^'* 
possession of considerable perceptive 

powers and of strong passions, seems to have been more effec- 
tive with the Lamellicorns than with any other family ot 
beetles. With some species the males are provided with weap* 

Fig. 24.— ChiasognatVius grantfl, 

'* " Ann. Soc. Entomolog. France." 1866. as quoted in " Journal ot TraveV by A. MuP 
|Mgr> x868, p. 135. 



(part n. 

ons for fighting ; some live in pairs and show mutual affec- 
tion ; many have the i)()wer of stridulating when excited; 
many arc furnished with the most extraordinary horns, a[)- 
parently for the sake of ornament ; and soinc, which are 
diurnal in their habits, are gorgeously colored. Lastly, sev- 
eral of the largest beetles in the world belong to this family^ 
which was placed by Linnaeus and Fabricius at the head of the 

Siridulating Organs. — Beetles belonging to many and widely 
distinct families possess these organs. The sound thus pro- 
duced 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 colors, and having a very elegant 
appearance under the microscope. In some cases, as with 
Typhoeus, minute, bristly, or scale-like prominences, with 
which the whole surrounding surface is covered in approxi- 
mately parallel lines, could be traced passing into the ribs of 
the rasp. The transition takes place by their becoming con- 
fluent 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. Left-hand figure, part dk 

the rasp highly magnified. 

These organs are situated in widely different positions. In 
the carrion-beetles (Necrophorus) two parallel rasps (r, fig. 25) 
stand on the dorsal surface of the fifth abdominal segment, 

'2 Westwood, " Modem Class." vol. i. p. culionidae," "Annals and Mag. of Nat 
184. Hist." vol. vi. i860 p. 14. 

'3 Wollaston, " On Certain Musical Cur- 

;f?Ap, X.1 



r :r,h rasp'''' consisting of 126 to 140 fine ribs. These ribs are 
scTaned against the posterior margins of the elytra, a small jior- 
tion of which projects beyond the general outline. In many 
Crioceridae, and in Clythra ^-pu?ictata (one of the Chrysome- 
lidae), and in some Tenebrionidae, etc.,*-^ 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 Carabidse'' the parts are completely 
reversed in position, for the rasps are seated 
on the inferior surface of the elytra, near 
their apices, or along their outer margins, 
and the edges of the abdominal segments 
serve as the scrapers. In Felobius Her- 
manni (one of Dytiscidae, 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 be- 
coming gradually finer at both ends, espe- 
cially at the upper end ; when this insect 
is held under water or in the air, a stridu- 
lating noise is produced by the extreme 
horny margin of the abdomen being scraped 
against the rasps. In a great number of long- 
horned beetles (Longicornia) the organs are TaS^' 
situated quite otherwise, the rasp being on 
the meso-thorax, which is rubbed against the pro- thorax ; Lan- 
dois counted 238 very fine ribs on the rasp of Cerambyx heros. 
Many Lamellicorns have the power of stridulating, and the 
organs differ greatly in position. Some species stridulate very 
ioudly, so that when Mr. F. Smith caught a Trox sadulosus, a 

Fig. 26. — Hinc'-tegol 

Geotrupes stercorarius 
(from Landois). r. 
Rasp. c. Coxa. J". 
t. Tibia, tr. 

'* Landois, "Zeitschrift fiir Wiss. Zoolog." 
f>. xvii. 1867, s. 127. 

^* I am grcritly indebted to Mr. G. R. 
Crotch for having sent me many prepared 
specimens of various beetles belonging to 
these three families and to others, as well as 
for valuable information. He believes that 
the power of stridulation in the Clythra has 
not been previously observed. I am also 
much indebted to Mr. E. W. Janson, for in- 
formation and specimens. I may add that 
my son, Mr. V. Darwin, finds that Dennes- 
tes murinus striuulatcs, hut he searched in 
vain for the apparatus. Scolytus has lately 
6eea de;rxibcd by Dr. Chapman as a stridu- 

lator, in the " Entomologist's Monthly Mag- 
azine," vol. vi. p. 130. 

■" Schiodte, translated in " Annals and 
Mag. of Nat. Hist." vol. xx. 1867, p. 37. 

'^ Westring has described (Kroyer, " Nat- 
urhist. Tidskrift," B. ii. 1848-49, p. 334) the 
stridulating organs of these two, as well as 
in other families. In the Carab'idae I have 
examined Klaphrus uliginosus and Blethu 
sa mult I punctata, sent to me by Mr. 
Crotch. In Blcthisa the transverse ridges 
on the furrowed border of the abdominal 
segment do not, as far as I could judge, 
come into play in scraping the rasps on tke 


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. 26) the coxa of each hind-leg (having in G. stercorarius 
84 ribs), which is scraped by a specially projecting part of one 
of the abdominal segments. In the nearly allied Copris luna- 
ris, an excessively narrow fine rasp runs along the sutural 
margin of the elytra, with another sharp rasp near the basal 
outer margin ; but in some other Coprini the rasp is seated, 
according to Leconte,"*^ on the dorsal surface of the abdomen. 
In Oryctes it is seated on the pro-pygidium ; and, according 
to the same entomologist, in some other Dynastini, on the 
under surface of the elytra. Lastly, Westring states that in 
Omaloplia brunnea the rasp is placed on the pro-sternum, 
and the scraper on the meta-sternum, the parts thus occupy- 
ing the under surface of the body, instead of the upper sur- 
face, as in the Longicorns. 

We thus see that in the different coleopterous families the 
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 origi- 
nally various beetles made a shuffling or hissing noise by the 
rubbing together of any hard and rough parts of their bodies 
which happened to be in contact ; and that, from the noise 
thus produced being in some w^ay 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 informs me that 
the Euchirus longimanus (a Lamellicorn, with the anterior legs 
wonderfully elongated in the male) '' makes, while moving, a 
low hissing sound by the protrusion and contraction of the 
abdomen ; and when seized it produces a grating sound by 
rubbing its hind-legs against the edges of the elytra." The 
hissing sound is clearly due to a narrow rasp running along the 
sutural margin of each elytron ; and I could likewise make the 
grating sound by rubbing the shagreened surface of the femur 
against the granulated margin of the corresponding elytron ; 
but I could not here detect any proper rasp \ nor is it likely 
that I could have overlooked it in so large an insect. After 

'8 I am indebted to Mr. Walsh, of Illinois, for having sent me extracts from Lecx^te'v 
*'■ Introduction to Entomology," pp. loi, 143. 


examining Cychnis, and reading what Westring has writ- 
ten about this beetle, it seems very doubtful whether it pos- 
sesses any true rasp, though it has the power of emitting a 

From the analogy of the Orthoptera and Homoptera, I ex- 
pected to find the stridulating organs in the Coleoptcra differ- 
ing according to sex ; but Landois, who has carefully examined 
several species, observed no such difference ; nor did Westring ; 
nor did Mr. G. R. Crotch in preparing the many specimens 
which he had the kindness to send me. Any difference in 
these organs, if slight, would, however, be difficult to detect, on 
account of their great variability. Thus, in the first pair of 
specimens of Necrophorus hmnator and of Pclobius which I ex- 
amined, the rasp was considerably larger in the male than in 
the female; but not so with succeeding specimens. In Geo- 
trupes stercorarius the rasp appeared to me thicker, opaquer, 
and more prominent in three males than in the samx? number 
of females ; in order, therefore, to discover whether the sexes 
differed in their power of stridulating, my son, Mr. F. Darwin, 
collected fifty-seven living specimens, which he separated into 
two lots, according as they made a greater or lesser noise, when 
held in the same manner. He then examined all these spe- 
cimens, and found that the males were very nearly in the same 
proportion to the females in both the lots. Mr. F. Smith has 
kept alive numerous specimens oi Monoynchus pseudacori {flwx- 
culionidae) and is convinced that both sexes stridulate, and ap' 
parently 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 (Tenebrionidai) 
possess stridulating organs. I examined five males of H. gibbus, 
and in all these there was a well-developed rasp, partially 
divided into two, on the dorsal surface of the terminal abdom- 
inal segment ; while in the same number of females there was 
not even a rudiment of the rasp, the membrane of this segment 
being transparent, and much thinner than in the male. In H. 
cribratostriaius 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 
s^bdominal rasp ; whether these ridges serve as an independent 

^A THE DESCENT OF MAN. (part il 

rasp, or as a scraper for the abdominal rasp, I could not decide : 
the female exhibits no trace of this latter structure. 

Again, in three species '^f the Lamellicorn genus Oryctes we 
have a nearly parallel case. In the females of (9. gryphus and 
nasicornis the ribs on the rasp of the pro-pygidium are 1<.*S3 
continuous and less distinct than in the males ; but the chief 
difference is that the whole upper surface of this segment, when 
held in the proper light, is seen to be clothed with hairs, which 
are absent or are represented by excessively fine down in the 
males. It should be noticed that in all Coleoptera the effective 
part of the rasp is destitute of liairs. In O. seriegalensis the 
difference between the sexes is more strongly marked, and this 
is best seen when tVe 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 ; while m 
the male these crests in proceeding toward the apex become 
more and more confluent, regular, and naked ; so that three- 
fourths of the segment is covered with extremely fine parallel 
Tibs, which are quite absent in the female. In the females, 
however, of all three species of Oryctes, a slight grating or 
stridulating sound is produced when the abdomen of a softened 
specimen is pushed backward and forward. 

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 striduLi^'m 
apparently serves both sexes as a mutual call. iJeeties stridu- 
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 denance ; 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 v/ere 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 waen she 
is removed.'® Some naturalists believe that beetles make this 
:ioise to frighten away their enemies ; but I cannot think that 
a quadruped or bird, able to di)vour a large beetle, would 
be frightened by so sHght a sound. Tho 6ep>f that the stridu- 
lation serves as a sexual call is supported by the fact that death- 
ticks {AiiGbium tessellatuni) are well known to answer each 

" M, P. dc la Bri>lerie» as ^juoted in "Journal of Travd," A. Murray, voL i. zS6S) pi 


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 afterwai'd he has found her united with a male, and on one 
occasion surrounded by several males. Finally, it is probablr 
that the two sexes of many kinds of beetles were at first en-^ 
abled 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. 


INSECTS, continued. — order, lepidoptera. 


Courtship of butterflies — Battles — Ticking noise — Colors common to both 
sexes, or more brilliant in the males — Examples — Not due to the 
direct action of the conditions of life — Colors adapted for protection 
— Colors of moths — Display — Perceptive powers of the Lepidoptera — • 
yariability — Causes of the difference in color between the males and 
females — Mimicry, female butterflies more brilliantly colored than 
the males — Bright colors of caterpillars — Summary and concluding 
remarks on the secondary sexual characters of insects — Birds and 
insects compared. 

In this great Order the most interesting points for us are the 
differences in color between the sexes of the same species, and 
between the distinct species of the same genus. Nearly the 
whole of the following chapter will be devoted to this subject : 
but I will first make a few remarks on one or two other points. 
Several males may often be seen pursuing and crowding round 
the same female. Their courtship appears to be a prolonged 
affair, for I have frequently watched one or more males pirouet- 
ting round a female until I was tired, without seeing the end 

■" According to Mr. Doubleday, "the noise B. xvii. s. 131. Oliver says (as quoted by 

is produced by the insect raising itself on its Kirby and Spcnce, " Introduct." vol. ii. p. 

legs as high as it can, and then striking its 395) that the female of Pimelia striata pro. 

thorax five or six times, in rapid succession, duces a rather loud sound by striking hei 

against the substance upon which it is sit- abdomen against any hard substance, " an4 

ting." For references on this subject see that the male, obedient to this call, soon afc 

Landois, "Zeitschrift fik Wissen. Zoolog." tends her, and they pair.'' 

326 THE DESCENT OF MAN, (part il. 

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 j)ertinaciously refused him, and at 
last settled on the ground and closed her wings, so as to escape 
from his addresses. 

Although butterflies are weak and fragile creatures, they are 
pugnacious, and an Emperor butterfly ^ has been captured with 
the tips of its wings broken from a conflict with another male. 
Mr. Collingwood, in speaking of the frequent battles between 
the butterflies of Borneo, says, '' They whirl round each other 
with the greatest rapidity, and appear to be incited by the 
greatest ferocity." 

The Ageronia feronia makes a noise like that produced by a 
toothed wheel passing under a spring catch, and which can be 
heard at the distance of several yards : I noticed this sound at 
Rio 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. ^ 

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 
prasinana, and which he believes to be produced, as in Cicada, 
by an elastic membrane, furnished with a muscle. He quotes, 
also, Guenee, that Setina produces a sound like the ticking of 
a watch, apparently by the aid of ^'two large tympaniform 
vesicles, situated in the pectoral region ;" and these '' are much 
more developed in the male than in the female." Hence the 
sound-producing organs in the Lepidoptera appear to stand in 
some relation with the sexual functions. I have not alluded 
to the well-known noise made by the Death's Head Sphinx, for 
it is generally heard soon after the moth has emerged from its 

Girard has always observed that the musky odor 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. 

Everyone must have admired the extreme beauty of many 

^ Apatura Iris: "The Entomologist's production of the sound. For the case of 

Weekly Intelligence," 1859, p. 139. For the Thecophora, see "Zoological Record," 1869, 

Bornean Butterflies, see C. Collingwood, p. 401. For Mr. Buchanan White's observa- 

" Rambles of a Naturahst," 1868, p. 183. tions, "The Scottish Naturalist," July, 1872, 

' See my "Journal of Researches," 1845, p. 214. 
p. 33. Mr. Doubleday has detected (" Proc. ^ " The Scottish Naturalist," July, 1872, 

Ent. Soc." March 3, 1845, p. 123) a peculiar p. 213. 

membranous sac at the base of the front * "Zoological Record," 1869, p. 347. 
wings, which is probably connected with the 


butterflies and of some moths; and it may be asked, are their 
colors and diversified patterns the result of the direct action of 
the physical conditions to which these insects have been ex- 
posed, without any benefit being thus derived ? Or have suc- 
cessive variations been accumulated and determined as a pro- 
tection, or for some unknown purpose, or that one sex may be 
attractive to the other? And, again, what is the meaning of 
the colors being widely different in the males and females of 
certain species, and alike in the two sexes of other species of 
the same genus ? Before attempting to answer these questions 
a body of facts must be given. 

With our beautiful English butterflies, the admiral, peacock, 
and painted lady (Vanessse). as well as many others, the sexes 
are alike. This i.^ also the case with the magnificent Heli- 
conidae, and most of the Danaidae in the tropics. But in cer- 
tain other tropical groups, and in some of our English butter- 
flies, as the purple emperor, orange-tip, etc. {Apatura Iris and 
Anthocharis cardamines)^ the sexes differ either greatly or 
slightly in color. No language suffices to describe the splendor 
of the males of some tropical species. Even within the same 
genus we often find species presenting extraordinary differences 
between the sexes, while others have their sexes closely alike. 
Thus in the South American genus Epicalia, Mr. Bates, to 
whom I am indebted for- most of the following facts, and for 
looking over this whole discussion, informs me that he knows 
twelve species the two sexes of which haunt the same stations 
(and this is not always the case with butterflies), and which, 
therefore, cannot have been differently affected by external 
conditions.^ In nine of these twelve species the males rank 
among the most brilliant of all butterflies, and differ so greatly 
from the comparatively plain females that they were formerly 
placed in distinct genera. The females of these nine species 
resemble each other in their general type of coloration ; and 
vhey likewise resemble both sexes of the species in several allied 
genera, found in various parts of the world. Hence we may 
infer that these nine species, and probably all the others of the 
genus, are descended from an ancestral form which was colored 
in nearly the same manner. In the tenth species the female 
still retains the same general coloring, but the male resembles 
her, so that he is colored in a much less gaudy and contrasted 

• See also Mr. Bates's paper in " Proc. regard to Diadema, in "Transact. Eats* 
Ent. Soc. of Philadelphia," 1865, p. 206. molog. Soc. of London," 1869, p. «78. ^ 

Also Mr. Wallace on the same subject, ia 

328 THE DESCENT OF MAN. [part ii. 

manner than the males of the previous species. In the elev- 
enth and twelfth species the females depart from the usual 
type, for they are gayly decorated almost like the males, but in. 
a somewhat less degree. Hence in these two latter sj)ecies the 
bright colors of the males seem to have been transferred to the 
females ; while in th(j tenth species the male has either retained 
or recovered the plain colors of the female, as well as of the 
parent-form of the genus. The sexes in these three cases have 
thus been rendered nearly alike, though in an opposite man- 
ner. In the allied genus Eubagis, both sexes of some of the 
species are plain-colored and nearly alike ; while with the 
greater number the males are decorated with beautiful metallic 
tints in a diversified manner, and differ much from their fe- 
males. The females throughout the genus retain the same 
general style of coloring, so that they resemble one another 
much more closely than they resemble their own males. 

In the genus Papilio, all the species of the ^neas group are 
remarkable for their conspicuous and strongly contrasted 
colors, and they illustrate the frequent tendency to gradation 
in the amount of difference between the sexes. In a few 
species, for instance in P. ascanius, the males and females are 
alike ; in others the males are either a little brighter or very 
much more superb than the females. The genus Junonia, 
allied to our Vanessae, offers a nearly parallel case, for 
although the sexes of most of the species resemble each other, 
and are destitute of rich colors, yet in certain species, as iny. 
cenone, the male is rather more bright-colored than the female, 
and in a few (for instance y. andremiajd) the male is so differ- 
ent 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 Ameri- 
can Theclse, in which both sexes are nearly alike and wonder- 
fully splendid ; in another species the male is colored in a 
similarly gorgeous manner, while the whole upper surface of 
the female is of a dull uniform brown. Our common little 
English blue butterflies of the genus Lycaena illustrate the 
various differences in color betv/een the sexes almost as well, 
though not in so striking a manner, as the above exotic 
genera. In Lycmna ages f is both sexes have wings of a brown 
color, bordered with small ocellated orange spots, and are thus 
alike. In Z. cegon the wings of the male are of a fine blue, 
bordered with black ; while those of the female are brown. 


with a similar border, closely resembling the wings of Z, 
agestis, Lastly, in L. arion both sexes are of a blue color and 
are very like, tliough in the female the edges of the wings are 
rather duskier, with the black spots plainer ; and in a brighi 
blue Indian species both sexes are still more alike. 

I have given the foregoing details in order to show, in the 
first place, that when the sexes of butterflies differ the male, as 
a general rule, is the more beautiful, and dei)arts more from the 
usual type of coloring of the group to which the species be- 
longs. Hence in most groups the females of the species 
resemble each other much more closely than do the males. In 
some cases, however, to which I shall hereafter allude, Che fe- 
males are colored more splendidly than the males. In the sec- 
ond 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 color to so great 
a difference that it was long before the two were placed by 
entomologists in the same genus. In the third place, we have 
seen that when the sexes nearly resemble each other, this ap- 
pears due either to the male having transferred his colors to the 
female, or to the male having retained, or perhaps recovered, 
the primordial colors of the group. It also deserves notice 
that in those groups in which the sexes differ the females 
usually somewhat resemble the males, so that when the males 
are beautiful to an extraordinary degree, the females almost in- 
variably 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 
conclude that the causes have generally been the same which 
have determined the brilliant coloring of the males alone of 
some species, and of both sexes of other species. 

As so many gorgeous butterflies inhabit the tropics, it has 
often been supposed that they owe their colors to the great 
heat and moisture of these zones ; but Mr. Bates ^ has shown,' 
by the comparison of various closely allied groups of insects 
from the temperate and tropical regions, that this view cannot 
be maintained ; and the evidence becomes conclusive when 
brilliantly colored males and plain-colored females of the same 
species inhabit the same district, feed on the same food, and 
follow exactly the same habits of life. Even when the sexes 
resemble each other, we can hardly believe that their briUiant 

• *• The Naturalist on the Amazons," vol. i. 1863, p. 19. 

330 TITE DESCENT OF MAM. [part n. 

aiid beautifully arranged colors are the purposeless result of the 
nature of the tissues and of the action of the surrounding con- 

With animals of all kinds, whenever color 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 be- 
tween the sexes. With many species of butterflies the ujjper 
surfaces of the wings are obscure; and this in all i)robability 
leads to their escaping observation and danger. But butter- 
flies would be particularly liable to be attacked by their ene- 
mies when at rest ; and most kinds while 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 
colored so as to imitate the objects on which these insects 
commonly rest. Dr. Rossler, I believe, first noticed the sim- 
ilarity of the closed wings of certain Vanessse and other butter- 
flies 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, color, and veining, cannot be dis- 
tinguished from a withered leaf with its footstalk. In some 
other cases the lower surfaces of the wings are brilliantly 
colored, and yet are protective ; thus in The da rubi the wings 
when closed are of an emerald green, and resemble the young 
leaves of the bramble, on which in spring this butterfly may 
often be seen seated. It is also remarkable that in very many 
species, in which the sexes differ greatly in color on their upper 
surface, the lower surface is closely similar or identical in both 
sexes, and serves as a protection.^ 

Although the obscure tints both of the upper and under sides 
of many butterflies no doubt serve to conceal them, yet we can- 
not extend this view to the brilliant and conspicuous colors on 
the upper surface of such species as our admiral and peacock 
Vanessae, our white cabbage-butterflies (Pieris), or the great 
swallow-tail PapiHo which haunts the open fens — for these but- 
terflies are thus rendered visible to every living creature. In 
these species both sexes are alike ; but in the common brim- 
stone butterfly (^Gonepieryx rhamni), the male is of an intense 

'' See a very interesting article in the Science Gossip" for September, 1867, page 

" Westminster Review " for July, 1867, 196. 

page ID. A wood-cut of the Kallima is ^ Mr. G. Fraser, in "Nature," April, 

given by Mr, Wallace in '*Hardwicke's 1871, p. 489. 


yellow, while the female is much paler ; and in the orange-tip 
Anthocharis cardamines) the males alone have their wings tipped 
with bright orange. Both the males and females in these cases 
are conspicuous, and it is not credible that their differeiice in 
color should stand in any relation to ordinary protection. 
Prof. Weismann remarks^ that the female of one of the Lycaenae 
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 shows 
that the blue color cannot be in any way protective. Never- 
theless, it is probable that conspicuous colors are indirectly 
beneficial to many species, as a warning that they are unpal- 
atable. 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. genutid) probably show us the primordial colors 
of the parent-species of the genus ; for both sexes of lour or five 
widely distributed species are colored in nearly the same man- 
ner. As in several previous cases, we may here infer that it i? 
the males of Anth. cardamiiies and genutia which have departed 
from the usual type of the genus. In the Anth. sara from Cali- 
fornia, the orange-tips to the wings have been partially devel- 
0]:)ed in the female ; but they are paler than in the mak, and 
slightly different in some other respects. In an allied Indian 
form, the Iphias glatuippe^ the orange-tips are fully developed 
in both sexes. In this Iphias, as pointed out to me by Mr. A. 
Butler, the under surface of the wings marvellously resembles a 
pale-colored leaf; and in our English orange-tip, the under 
surface resembles the flower-head of the wild parsley, on which 
the butterfly often rests at night. ^^ The same reason which 
compels us to believe that the lower surfaces have here been col- 
ored for the sake of protection, leads us to deny that the wings 
have been tipped with bright orange for the same purpose, es- 
pecially when this character is confined to the males. 

Most Moths rest motionless during the whole or greater 

• " Einfluss der Isolirung auf die Art- T. W. Wood, " The Student," Sept, >*f8, 
bildung," 1872. p. 58. p. 8i. 

*• See the interesting observations by Mr. 

332 THE DESCENT OF MAM. [part il 

part of the day with their wings depressed, and tlie whole 
upper surface is often shaded and colored in an admirable 
inanner, a§ 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 colored without much risk; and 
they are in fact often thus colored. During flight, motha 
would often be able to escape from their enemies ; neverthe- 
less, as the hind- wings are then fully exposed to view, their 
bright colors must generally have been acquired at some little 
risk. But the following fact shows how cautious we ought to 
be in drawing conclusions on this head. The common Yellow 
Under-wings (Triphaena) often fly about during the day or 
early evening, and are then conspicuous from the color of their 
hind-wings. It would naturally be thought that this would 
be a source of danger ; but Mr. J. Jenner Weir believes that 
it actually serves them as a means of escape, for birds strike a? 
these brightly colored and fragile surfaces, instead of at the 
body. For instance, Mr. Weir turned into his aviary a vig- 
orous specimen of Triphana pronuba, which was instantly 
pursued by a robin ; but the bird's attention being caught by 
the colored wings, the moth was not captured until after about 
fifty attempts, and small portions 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 by Mr. Wallace,^^ namely, that in the 
Brazilian forests and Malayan islands, many common and 
highly decorated butterflies are weak flyers, though furnished 
with a broad expanse of wing ; and they ''are often captured 
with pierced and broken wings, as if they had been seized by 
birds, from which they had escaped ; if the wings had been 
much smaller in proportion to the body, it seems probable that 
the insect would more frequently have been struck or pierced 
in a vital part, and thus the increased expanse of the wings 
may have been indirectly beneficial." 

Display. — The bright colors of many butterflies and of 
some moths are specially arranged for display, so that they 
may be readily seen. During the night colors are not visible, 
and there can be no doubt that the nocturnal moths, taken as 

J* Mr. Wallace in " Hardwicke's Science paper in "Transact Ent. Society," 1869, p. 
Gossip.'" Sept. 1867, p. 193. 23. 

w See also, on this subject, Mi. Weir's ^3 " Westmmster Rev." July, 1867, p. x& 


a body, are much less gayly decorated than butterflies, all of 
which are diurnal in their habits. But the moths of certain 
famihes, such as the Zygaenidoe, several Sphingidse, Uraniidse, 
some Arctiidae and Saturniidas, fly about during the day or 
early evening, and many of these are extremely beautiful, be- 
ing far brighter colored than the strictly nocturnal kinds. A 
few exceptional cases, however, of bright-colored nocturnal 
species have been recorded.^"* 

There is evidence of another kind in regard to display. 
Butterflies, as before remarked, elevate their wings when at 
rest, but while basking in the sunshine often alternately raise 
and depress them, thus exposing both surfaces to full view ; and 
although the lower surface is often colored in an obscure man- 
ner as a protection, yet in many species it is as highly dec- 
orated as the upper surface, and sometimes in a very different 
manner. In some tropical species the lower surface is even 
more brilliantly colored than the upper. ^^ In the English 
fritillaries {Argynnis) the lower surface alone is ornamented 
with shining silver. Nevertheless, as a general rule, the upper 
surface, which is probably more fully exposed, is colored more 
brightly and diversely than the lower ; hence the lower sur- 
face generally affords to entomologists the more useful character 
for detecting the affinities of the various species. Fritz Miiller 
informs me that three species of Castnia are found near his 
house in South Brazil : of two of them the hind-wings are ob- 
scure, 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, v/e find this side very rarely 
colored with a brightness greater than, or even equal to, that 
of the upper side. Some exceptions to the rule, either real or 
apparent, must be noticed, as the case of Hypopyra ^^ Mr. 
Trimen inform me that in Guenee's great work three moths 

I* For instance, Lithosia ; but Prof. West- and lower surfaces of the wings of several 

wood (" Modern Class, of Insects," vol. ii. species of Papilio may be seen in the beau- 

p. 390) seems surprised at this case. On tiful plates to Mr. Wallace's " Memoir on 

the relative colors of diurnal and nocturnal the Paoilionidac of the Malayan Region," in 

Lepidoptera, see ibid. pp. 333 and 392 ; also "Transact. Linn. Soc." vol. xxv. part. L 

Harris, "Treatise on the Insects of New 1865. 

England," 1842, p. 315. as See Mr. Wormaldon thismoth* "PlOU 

*» Such dififerences between the upper Ent Soc," M*"**» - 'ft^- 

334 5r^^ DESCENT OF MAM, (part il 

are figured, in which the under surface is much the more brill- 
iant. For instance, in the Austrahan Gastrophora the upper 
surface of the fore-wing is pale grayish-ochreous, while the 
lower surface is magnificently ornamented by an ocellus of 
cobalt-blue, placed in the midst of a black mark, surrounded 
by orange-yellow, and this by bluish- white. But the habits of 
these three moths are unknown, so that no explanation can be 
given of their unusual style of coloring. Mr. Trimen also in- 
forms me that the lower surface of the wings in certain other 
Geometrae ^'^ and quadrifid Noctuas are either more variegated 
or more brightly colored 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 consid- 
erable 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 sur- 
face in certain moths is not so anomalous as it at first appears. 
The Saturniidae include some of the most beautiful of all 
moths, their wings being decorated, as in our British Emperor 
moth, with fine ocelli ; and Mr. T. W. Wood ^^ observes that 
they resemble butterflies in some of their movements ; ''for 
instance, in the gentle waving up and down of the wings as if 
for display, which is more characteristic of diurnal than of 
nocturnal Lepidoptera." 

It is a singular fact that no British moths which are brill- 
iantly colored, and, as far as I can discover, hardly any for- 
eign species, differ much in color according to sex ; though 
this is the case with many brilHant 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 ; while the wings of the female are purple- 
brown, marked with gray lines. ^^ The British moths which 
differ sexually in color are all brown, or of various dull yellow 
tints, or nearly white. In several species the males are much 
darker than the females,^ and these belong to groups which 
generally fly about during the afternoon. On the other hand, 

>•' See also an account of the S. American cabinet that the males are darker than the 

genus Erateina (one of the Geometrae) in females in the Lasiocatnpa quercus, Odo- 

'• Transact. Ent. Soc." new series, vol. v. pi. tiestis potatoria^ Hypogymna dispar, Da- 

XV. and xvi. sychira pudibunda^ and Cycnia Tnendica. 

is " Proc. Ent. Soc. of London," July 6, In this latter species the difference in color 

1868, p. xxvii. between the two sexes is strongly marked ; 

19 Harris, " Treatise," etc., edited by and Mr. Wallace informs me that we here 

Flint, 1862, p. 395. have, as he believes, an instance of pro- 

•• For instance, I observe in my son's tcctive mimicry confined to one sex, as wiU 


ii) many genera, as Mr. Stainton informs me, the males have 
the hind-wings whiter than those of the female — of which fact 
Agrotis exclamationis offers a good instance. In the Ghost 
Moth {Hepialus humuli) the difference is more strongly 
marked ; the males being white, and the females yellow with 
darker markings. ^i It is probable that in these cases the males 
are thus rendered more conspicuous, and more easily seen by 
the females while flying about in the dusk. 

From the several foregoing facts it is impossible to admit 
that the brilliant colors of butterflies, and of some few moths, 
have commonly been acquired for the sake of protection. We 
have seen that their colors and elegant patterns are arranged 
and exhibited as if for display. Hence I am led to believe 
that the females prefer or are most excited by the more brilliant 
males ; for on any other supposition the males would, as far as 
we can see, be ornamented to no purpose. We know that ants 
and certain Lamellicorn beetles are capable of feeling an attach- 
ment for each other, and that ants recognize their fellows after 
an interval of several months. Hence there is no abstract im- 
probability in the Lepidoptera, which probably stand nearly 
or quite as high in the scale as these insects, having sufficient 
mental capacity to admire bright colors. They certainly dis- 
cover flowers by color. The Humming-bird Sphinx may often 
be seen to swoop down from a distance on a bunch of flow- 
ers in the midst of green foliage ; and I have been assured, by 
two persons abroad, that these moths repeatedly visit flowers 
painted on the walls of a room, and vainly endeavor to insert 
their proboscis into them. Fritz Miiller informs me that sev- 
eral kinds of butterflies in South Brazil show an unmistakable 
preference for certain colors 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 effect. As I hear 
from Mr. Doubleday, the common white butterfly often flies 

hereafter be more fully explained. The '* It is remarkable that in the Shetland 
white female of the Cycnia resembles the Islands the male of this moth, instead of 
very common Spilosoina menthrasti, both differing widely from the female, frequently 
sexes of which are white ; and Mr. Stainton resembles her closely in color (see Mr. Mac- 
observed that this latter moth was rejected Lachlan, "Transact. Ent. Soc." vol. ii. 
v. ith utter disgust by a whole brood of young 1866. p. 459). Mr. G. Frascr suggests 
tiukeys, which were fond of eating other (" Nature," April, 1871, p. 489) that at the 
moths ; so that if the Cycnia was commonly season of the year when the ghost moth ap- 
mistaken by British birds for the Spilosoma, pears in these northern islands, the whiteness 
it would escape being devoured, and its of the males would not be needed to render 
white deceptive color would thus be highly them visible to the females in the twilight 
beneiiciaL. night* 

336 THE DESCENT OF MAN. [part it 

down to a bit of paper on the ground, no doubt mistaking it 
ibr 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 pro- 
longed affair. The males sometimes fight together in rivalry ; 
and many may be seen pursuing or crowding round the same 
female. Unless, then, the females prefer one male to another, 
the pairing must be left to mere chance, and this does not 
appear probable. If, on the other hand, the females habitually, 
or even occasionally, prefer the more beautiful males, the 
colors of the latter will have been rendered brighter by de- 
grees, 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 
butterflies prefer the more beautiful males ; thus, as I have 
been assured by several collectors, fresh females may frequently 
be seen paired with battered, faded, or dingy males ; but this is 
a circumstance which could hardly fail often to follow from tht* 
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 leas<^ 
choice in regard to their partners. This is the case with the 
common silk-moth {B. mori), as I have been told by some 
continental and English breeders. Dr. Wallace, who has had 
great experience in breeding Bomhyx cynithia, 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 thos^ 

8="Rsrabks Qf s ^latur^lUt io th? Chinese 3?a§," i868, p. \^ 


endowed whh most vitality. Nevertheless, the Bombycidae, 
though obFcurely colored, are often beautiful to our eyes from 
their elegant and mottled shades. 

I have as yet only referred to the species in which the males 
are brighter colored than the females, and I have attributed 
their beauty to the females for many generations having chosen 
and paired with the more attractive males. But converse 
cases occur, though rarely, in which the females are more brill- 
iant than the males ; and here, as I believe, the males have 
selected the more beautiful females, and have thus slowly added 
to their beauty. We do not know why in various classes of 
animals the males of some few species have selected the more 
beautiful females instead of having gladly accepted any female, 
as seems to be the general rule in the animal kingdom ; but if, 
contrary to what generally occurs with the Lepidoptera, the 
females were much more numerous than the males, the latter 
would be likely to pick out the more beautiful females. Mr. 
Butler showed me several species of Callidryas in the British 
Museum, in some of which the females equalled, and in others 
greatly surpassed, the males in beauty ; for the females alone 
have the borders of their wings suffused with crimson and 
orange, and spotted with black. The plainer males of these 
species closely resemble each other, showing that here the 
females have been modified ; whereas in those cases where the 
males are the more ornate, it is these which have been modified, 
the females remaining closely alike. 

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 
colored than their males. Again, the females of Colias edusa 
and hyale have " orange or yellow spots on the black mar- 
ginal 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 

(0}-VoU 9 

33S THE DESCENT OE MAN, (part ii, 

their Ideality seems to have been increased hy the females hav- 
ing accepted the more attractive individuals; but with these 
butterflies the females take the more active part in the final 
marriage ceremony, so that we may suppose that they likewise 
do so in the wooing ; and in this case we can understand how 
it is that they have been rendered the more beautiful. Mr. 
Meldola, from whom the foregoing statements have been taken ^ 
says in conclusion : ** Though I am not convinced of the ac- 
tion of sexual selection in producing the colors 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 
vords must be added on this subject. In respect to color there 
is no difficulty, for any number of highly variable Lepidop- 
tera could be named. One good instance will suffice. Mr. 
Bates showed me a whole series of specimens of Papilio sesostris 
and P. childrencB ; in the latter the males varied much in the 
extent of the beautifully enamelled green patch on the fore- 
wings, and in the size of the white mark, and of the splendid 
crimson stripe on the hind-wings ; so that there was a great 
contrast among the males between the most and the least gaudy. 
The male of Papilio sesostris is much less beautiful than of P. 
childrencB ; and it likewise varies a little in the size of the green 
patch on the fore-wings, and in the occasional appearance of 
the small crimson stripe on the hind-wings, borrowed, as it 
would seem, from its own female ; for the females of this and 
of many other species in the ^neas group possess this crim- 
son stripe. Hence, between the brightest specimens of P. se- 
sostris and the dullest of P. childrejice, there was but a small 
interval ; and it was evident that, as far as mere variability is 
concerned, there would be no difficulty in permanently in- 
creasing the beauty of either species by means of selection. 
The variability is here almost confined to the male sex ; but 
Mr. Wallace and Mr. Bates have shown ^ that the females of 
some species are extremely variable, the males being nearly 
constant. In a future chapter I shall have occasion to show 

38 " Nature," April 27, 1871, p. 508. Mr. Malayan Region, in "Transact. Linn. Soc." 

Meldola quotes Donzel, in " Soc, Ent. de vol. xxv. 1865, pp. 8, 36. A striking case of 

France," 1837, P' 77> °" ^^ flight of butter- a rare variety, strictly intermediate be- 

flies while pairing. See also Mr. G. Fraser, tween two other well-marked female varie- 

in " Nature," April 20, 1871, p. 489, on the ties, is given by Mr. Wallace. See also Mr. 

sexual differences of several British butter- Bates, in " Proc, Entomolog, Soc.," Nov. 

6ies. 19, 1866, p. xi, 

34 Wal^ice on the Papilionida of the 


that the beautiful eye-hke 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 selec- 
tion ; 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 inexpli- 
cable ; but if it should hereafter be found that the formation of 
an ocellus is due to some change in the tissues "f the wings, 
for instance, occurring at a very early period of development, 
we might expect, from what we know of the laws of inheritance, 
that it would be transmitted to both sexes, though arising and 
perfected in one sex alone. 

On the whole, although many serious objectio'os may be 
urged, it seems probable that most of the brilliantly colored 
species of Lepidoptera owe their colors to sexual sele<:tion, ex- 
cepting in certain cases, presently to be mentioned, in which 
conspicuous colors have been gained through mimicry as a 
protection. From the ardor of the male throughout the ani- 
mal kingdom, he is generally willing to accept any female ; 
and it is the female which usually exerts a choice. Hence, if 
sexual selection has been efficient with the Lepidoptera, the 
male, when the sexes differ, ought to be the more brilliantly 
colored, and this undoubtedly is the case. When both sexes 
are brilliantly colored and resemble each other, the characters 
acquired by the males appear to have been transmitted to both. 
We are led to this conclusion by cases, even within the s^me 
genus, of gradation from an extraordinary amount of difference 
to identity in color between the two sexes. 

But it may be asked whether the differences in color be- 
tween the sexes may not be accounted for by other means be- 
sides sexual selection. Thus the males and females of the same 
species of butterfly are in several cases known ^^ to inhabit 
different stations, the former commonly basking in the sun 
shine, the latter haunting gloomy forests. It is therefore pos- 
sible that different conditions of life may have acted directly 
on the two sexes ; but this is not probable,^ as in the adult state 
they are exposed to different conditions during a very short 
period ; and the larvae of both are exposed to the same con- 
ditions. Mr. Wallace believes that the difference between th<« 

*\ Mr. Bates was so kind as to lay this lace, in "Transact. Linn. Soc." vol. xxv. 

subject before the Entomological Society, 1865, p. 10. 

and I have received answers to this effect '^ On this whole subject see " Thf Variup 

from several entomologists. tion of Animals and Plants under DoiacftHU 

" H. W. Hates, " The Naturalist in the cation," i&68» vol. ii. chap, xxiii. 
Amazons," vol ii. 1863, p. 228. A. R. Wal- 


340 TBE DESCENT OF MAN. (part n. 

sexes fs due not so much to the males having been modified, aa 
to the females having, in all or almost all cases, accjuired dull 
colors for the sake of protection. It seems to me, on the con- 
trary, 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 show us approximately the primordial coloring of the 
parent-species of the group to which they belong. They have, 
however, almost always been somewhat modified by the trans- 
fer to them of some of the successive variations, through the 
accumulation of which the males were rendered beautiful. But 
1 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 con- 
ditions, and may have been thus affected ; though with the 
males any slight change of color thus caused will generally 
have been masked by the brilliant tints gained through sexual 
selection. When we treat of Birds, I shall have to discuss the 
whole question, as to how far the differences in color between 
the sexes are due to the males having been modified through 
sexual selection for ornamental purposes, or to the females hav- 
ing been modified through natural selection for the sake of 
protection ; so that I will heie say but little on the subject- 

In all the cases in which the more common form of equal in- 
heritance by both sexes has prevailed, the selection of bright- 
colored males would tend to make the females bright-colored, 
and the selection of dull-colored females would tend to make 
the males dull. If both processes were carried on simulta- 
neously, 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 colors, or a 
greater number of males by being brightly colored and thus 
finding partners, succeeded in leaving more numerous off- 

In order to account for the frequent transmission of charac- 
ters to one sex alone, Mr. Wallace expresses his belief that the 
more common form of equal inheritance by both sexes can be 
changed through natural selection into inheritance by one sex 
alone, but in favor of this view I can discover no evidence. 
We know, from what occurs under domestication, that i^ew 


characters often appear, which from the first are transmitted to 
one sex alone ; and by the selection of such variations there 
would not be the slightest difficulty in giving bright colors to 
the males alone, and at the same time, or subsequently, dull 
colors to the females alone. In this manner the females of 
some 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 
transferrence of new characters to one sex alone, have been 
carried on with a multitude of species — that the males have 
been rendered more brilliant by beating their rivals, and the 
females more dull-colored by having escaped from their ene- 
mies. The male, for instance, of the common brimstone but- 
terfly (Gonepteryx) is of a far more intense yellow than the 
female, though she is equally conspicuous ; and it does not 
seem probable that she specially acquired her pale tints as a 
protection, though it is probable that the male acquired his 
bright colors as a sexual attraction. The female of Anthocharis 
cardamines does not possess the beautiful orange wing-tips of 
the male; consequently she closely resembles the white butter- 
flies (Pieris) so common in our gardens ; but we have no evi- 
dence 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 prob- 
able that she has simply retained to a large extent her pri- 
mordial colors. 

Finally, as we have seen, various considerations lead to the 
conclusion that with the greater number of brilliantly colored 
Lepidoptera it is the male which has been chiefly modified 
through sexual selection ; the amount of difference between 
the sexes mostly depending on the form of 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 color. As all the 
successive 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 differ- 

aa «*xhe Variation of Animals and Plants under Domestication,^' voL ii. chap, zil p. ajt.' 

342 THE DESCENT OF MAN. [part a 

ence to none at all between the sexes of allied species. These 
cases of gradation, it may be added, are much too common to 
favor the siipi)Osition that we here see females actually under- 
going the process of transition and losing their brightness for 
the sake of protection ; for we have every reason to conclude 
that at any one time the greater number of species are in a 
fixed condition. 

Mimicry. — This principle was first made clear in an admir- 
able paper by Mr. Bates,^ who thus threw a flood of light on 
many obscure problems. It had previously been observed that 
certain butterflies in South America, belonging to quite distinct 
families, resembled the Heliconidse so closely in every stripe 
and shade of color that they could not be distinguished save 
by an experienced entomologist. As the Heliconidae are col- 
ored in their usual manner, while the others depart from the 
usual coloring of the groups to which they belong, it is clear 
that the latter are the imitators, and the Heliconidae the imi- 
tated. Mr. Bates further observed that the imitating species 
are comparatively rare, while the imitated abound, and that 
the two sets live mingled together. From the fact of the Heli- 
conidae being conspicuous and beautiful insects, yet so numer- 
ous in individuals and species, he concluded that they must be 
protected from the attacks of enemies by some secretion or 
odor ; and this conclusion has now been amply confirmed,-* 
especially by Mr. Belt. Hence Mr. Bates inferred that the 
butterflies which imitate the protected species have acquired 
their present marvellously deceptive appearance through varia- 
ation and natural selection, in order to be mistaken for the 
protected kinds, and thus to escape being devoured. No ex- 
planation is here attempted of the brilliant colors of the imi- 
tated, but only of the imitating butterflies. We must account 
for the colors of the former in the same general manner as in the 
cases previously discussed in this chapter. Since the publica- 
tion of Mr. Bates's paper, similar and equally striking facts 
have been observed by Mr. Wallace in the Malayan region, by 
Mr. Trimen in South Africa, and by Mr. Riley in the -United 

As some writers have felt much difficulty in understanding 

'» ♦•Transact. Linn. Soc." vol. xxiii. 1862, "Linn. Transact." vol. xxvL 1869, p. 497. 

p. 455. Riley, " Third Annual Report on the Noxi- 

'0 «'Proc. Ent. Sec." Dec. j, 1866, p. ous Insects of Missouri," 1871, pp. 163-168. 

xlv. This latter essay is valuable, as Mr. Riley 

3* Wallace, "Transact. Linn. Soc." vol. here discusses all objections which have 

XXV. 1865, p. I : also "Transact. Ent. Soc." been raised against Mr. Bates's theory. 
vd. iv. (3d series), 1867, p. 301. Trimen, 


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 i)robably commenced long ago, between forms 
not widely dissimilar in color. In this case even a slight vari- 
ation would be beneficial, if it rendered the one species more 
like the other ; and afterward the imitated species might be 
modified to an extreme degree through sexual selection or other 
means ; and if the changes were gradual, the imitators might 
ca:^iIy 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 coloring 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 
color. A few instances have been given in this chapter ; and 
many more may be found in the papers of Mr. Bates and Mr. 

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 imi- 
tated form differ from each other in color, and the sexes of the 
imitating form differ in a like manner. Several cases have also 
been recorded where the females alone imitate brilliantly col- 
ored 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 modi- 
fied have been transmitted to her alone. It is, however, prob- 
able that some of the many successive variations would have 
been transmitted to, and developed in, the males, had not such 
males been eliminated by being thus rendered less attractive to 
the females ; so that only those variations were preserved 
which were from the first strictly limited in their transmission 
to the female sex. We have a partial illustration of these re- 
marks in a statement by Mr. Belt, ^ that the males of some of 
the Leptalides, which imitate protected species, still retain in a 
concealed manner some of their original characters. Thus in 
the males '' the upper half of the lower wing is of a pure white, 
while all the rest of the wings is barred and spotted with black, 
red, and yellow, like the species they mimic. The females 
have not this white patch, and the males usually conceal it by 
covering it with the upper wing, so that I cannot imagine its 
being of any other use to them than as an attractioa in court* 

%■% •« The Naturalist in Nicaragua," 1874, p. 385. 

344 '^^^^ DESCENT OF MAM. \VKwi il 

ship, when they exhibit it to the females, and thus gratify 
their deep-seated preference for the normal color of the Order 
to which the Leptalides belong." 

Bright Colors of Catei-pi liars. — While reflecting on the 
bej.uty of many butterflies, it occurred to me that some cater- 
pillars were splendidly colored ; 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 
colors of their larvae could be somehow explained. In the first 
place, it may be observed that the colors of caterpillars do not 
stand in any close correlation with those of the mature insect. 
Secondly, their bright colors do not serve in any ordinary 
manner as a protection. Mr. Bates informs me, as an instance 
of this, that the most conspicuous caterpillar which he ever 
beheld (that of a Sphinx) lived on the large green leaves of a 
tree on the open llanos of South America ; it was about four 
inches in length, transversely banded with black and yellow, 
and with its head, legs, and tail of a bright red. Hence it 
caught the eye of anyone who passed by, even at the distance 
of many yards, and no doubt that of every passing bird. 

I then appUed to Mr. Wallace, who has an innate genius for 
solving difficulties. After some consideration he replied : 
'* Most caterpillars require protection, as may be inferred from 
some kinds being furnished with spines or irritating hairs, and 
from many being colored green hke the leaves on which they 
feed, or being curiously like the twigs of the trees on which 
they li\2." 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 colored cater- 
pillars were protected by having a nauseous taste ; but as their 
skin is extremely tender, and as their intestines readily pro- 
trude 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 Mr. Wallace remarks, ' ^ distastefulness alone would 
be insuffi*^ient to protect a caterpillar, unless some outward sign 
indicated to its would-be destroyer that its prey was a disgust- 
ing morsel." Under these circumstances it would be highly 
advantageous to a caterpillar to be instantaneously and certain- 
ly recognized as unpalatable by all birds and other animals. 
Thus the most gaudy colors would be serviceable, and might 


have been gained by variation and the survival of the most 
easily recognized individuals. 

This hypothesis appears at first sight very bold, but when it 
was brought before the Entomological Society ^ it was sup- 
ported by various statements ; and Mr. J. Jenner Weir, who 
keeps a large number of birds in an aviary, informs me that he 
has made many trials, and finds no exception to the rule, that 
all caterpillars of nocturnal and retiring habits with smooth 
skins, all of a green color, and all which imitate twigs, are 
greedily devoured by his birds. The hairy and spinose kinds 
are invariably rejected, as were four conspicuously colored 
species. When the birds rejected a caterpillar, they plainly 
showed, by shaking their heads and cleansing their beaks, that 
they were disgusted by the taste.** Three conspicuous kinds 
of caterpillars and moths were also given to some lizards and 
frogs, by Mr. A. Butler, and were 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 recog- 
nized by their enemies, on nearly the same principle that poi- 
sons are sold in colored bottles by druggists for the good of 
man. We cannot, however, at present thus explain the ele- 
gant diversity in the colors of many caterpillars; but any 
species which had at some former period acquired a dull, mot- 
tled, or striped appearance, either in imitation of surrounding 
objects, or from the direct action of climate, etc., almost cer- 
tainly would not become uniform in color, 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 

Summary and Concluding Retnarks on Insects. — Looking back 
to the several Orders, we see that the sexes often differ in 
various characters, the meaning of which is not in the least 
understood. The sexes, also, often differ in their 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. 

" "Proc. Entoiiiolog. Soc." Dec. 3, 1866, pous facts in the "Third Annual Report on 

p. xlv., and March 4, 1867, p. Ixxx. the Noxious Insects ol Missouri," 1871, p. 

'« See Mr. J. Jenner Weir's paper on In- 148. Some opposed cases are, however, 

sects and Insectivorous Birds, in "Transact, given Iw Dr. Wallace and M. H. d'Orville, 

Ent. Soc. "1869, p. SI ; also Mr. Butler's pa- see " Zoological Record," 1869, p. 349. 
{)cr, ibid. p. 27< Mr. Riley has given iuialo^ 

34^ THE DESCENT OF MAN. [fart il 

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 near- 
ly so widely with insects as with the higher animals. Hence it 
])robably 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 de- 
veloped 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 ef- 
ficient 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 organization. 

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 orna- 
ments. From the small size of insects, we are apt to under- 
value their appearance. If we could imagine a male Chalco- 
soma (fig. i6), with its polished bronzed coat of mail, and its 
vast complex horns, magnified to the size of a horse, or even 
of a dog, it would be one of the most imposing animals in the 

The coloring of insects is a complex and obscure subject. 
When the male differs slightly from the female, and neither are 
brilliantly colored, it is probable that tlie sexes have varied in 

CHAP, yi.] SUMMARY O!^ INS RCT^. 347 

a slightly different manner, and that the variations have been 
transmitted by each sex to the same, without any benefit or 
evil thus accruing. When the male is brilliantly colored and 
differs conspicuously from the female, as with some dragon-flies 
and many butterflies, it is probable that he owes his colors to 
sexual selection ; while the female has retained a primordial or 
very ancient type of coloring, slightly modified by the agencies 
before explained. But in some cases the female has apparently 
been made obscure by variations transmitted ^o 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 pro- 
tected species inhabiting the same district. When the sexes 
resemble each other and both are obscurely colored, there is 
no doubt that they have been in a multitude of cases so colored 
for the sake of protection. So it is in some instances when 
both are brightly colored, for they thus imitate protected 
species, or resemble surrounding objects, such as flowers ; or 
they give notice to their enemies that they are unpalatable. In 
other cases in which the sexes resemble each other and are both 
brilliant, especially when the colors are arranged for display, 
we may conclude that they have been gained by the male sex 
as an attraction, and have been transferred to the female. We 
are more especially led to this conclusion whenever the same 
type of coloration prevails throughout a whole group, and we 
find that the males of some species differ widely in color from 
the females, while others differ slightly or not at all, with in- 
termediate gradations connecting these extreme states. 

In the same manner as bright colors have often been par- 
tially 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,/emales ; 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 certam male Orthop- 
tera are not fully developed until the last moult ; and that the 
colors of certain male dragon-flies are not fully developed until 
some little time after their emergence from the pupal state, and 
when they are ready to breed. 

Sexual selection implies that the more attractive individuals 
are preferred by the opposite sex ; and as with insects, when 
the sexes differ, it is the male which, with some rare excep- 

548 THE DESCEIsrr of MAK (part a 

tions, 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 sin* 
gular contrivances possessed by the males, such as great jaws, 
adhesive cushions, spines, elongated legs, etc., for seizing the 
female; for these contrivances show that there is some diffi- 
culty 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 improba- 
bility 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 cVance — that the female exerts no 
choice, and is not influencec oy the gorgeous colors or other 
ornaments with which the male is decorated. 

If we admit that the females of the Homoptera and Orthop- 
tera appreciate the musical tones of their male partners, and 
that the various instruments have been perfected through sexual 
selection, there is little improbabihty in the females of other 
insects appreciating beauty in form or color, and consequently 
in such characters having been thus gained by the males. But 
from the circumstance of color being so variable, and from its 
having been so often modified for the sake of protection, it is 
difficult to decide in how large a proportion of cases sexual 
selection has played a part. This is more especially difficult 
in those Orders, such as Orthoptera, Hymenoptera, and Coleop- 
tera, in which the two sexes rarely differ much in color ; for 
we are then left to mere analogy. With the Coleoptera, how- 
ever, 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 w^ith splendid metallic 
tints. Hence it seems probable that all these characters have 
been gained through the same means, namely, sexual selection. 
With butterflies we have the best evidence, as the males some- 
times take pains to display their beautiful colors ; and we caa* 


not 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 in- 
sects. Thus many male birds are highly pugnacious, and some 
are furnished with special weapons for fighting with their 
rivals. They possess organs which are used during the breed- 
ing-season for producing vocal and instrumental music. They 
are frequently ornamented with combs, horns, wattles, and 
plumes of the most diversified kinds, and are decorated with 
beautiful colors, all evidently for the sake of display. We shall 
find that, as with insects, both sexes in certain groups are 
equally beautiful, and are equally provided with ornaments 
which are usually confined to the male sex. In other groups 
both sexes are equally plain-colored and unornamented. Last- 
ly, in some few anomalous cases the females are more beautiful 
than the males. We shall often find, in the same group of 
birds, every gradation from no difference between the sexes, to 
an extreme difference. We shall see that female birds, like 
female insects, often possess more or less plain traces or rudi- 
ments 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. What- 
ever explanation applies to the one class probably applies to 
the other ; and this explanation, as we shall hereafter attemj?! 
^^ show in further detail, is sexual s^kctioa. 





Fishes : Courtship and battles of tlie males — Larger size of the females — 
Males, bright colors and ornamental appendages ; other strange char- 
acters — Colors and appendages acquired hy the males during the 
breeding-season alone — Fishes with both sexes brilliantly colored- 
Protective colors — The less conspicuous colors of the female cannot 
be accounted for on the })rinciple of protection — Male fishes building 
nests, and taking charge of the ova and young. Amphibians : l>>if- 
ferences in structure and color between the sexes — Vocal organs. 
Rei'TILES : Chelonians — Crocodiles — Snakes, colors in some cases 
protective — Lizards, battles of — Ornamental appendages — Strange 
ditferences in structure between the sexes — Colors — Sexual differences 
almost as great as with birds. 

We have now arrived at the great subkingdom of the Ver- 
tebrata, and will commence with the lowest class, that of 
Fishes. The males of Plagiostomous fishes (sharks, rays) and 
of Chimaeroid fishes are provided with claspers which serve 
to retain the female, like the various structures possessed by 
many of the lower animals. Besides the claspers, the males 
of many rays have clusters of strong sharp spines on their 
heads, and several rows along '' the upper outer surface of their 
pectoral fins." These are present in the males of some species, 
which have other parts of their bodies smooth. They are only 
temporarily developed during the breeding-season ; and Dr. 
Giinther suspects that they are brought into action as prehen- 
sile organs by the doubling inward and downward of the two 
sides of the body. It is a remarkable fact that the females and 
not the males of some species, as of Raia clavata, have their 
backs studded with large hook-formed spines.^ 

The males alone of the capeiin (^Mallotus villosuSy one of 
Salmonidae), are provided with a ridge of closely set, brush-hke 
scales, by the aid of which two males, one on each side, hold 
the female, while she runs with great swiftness on the sandy 
beach, and there deposits her spawn. ^ The widely distinct 
Monacanthus scopas presents a somewhat analogotis structure. 

* See Yarreirs " History of British Fish- spines in R. clavata are peculiar to the fo 
es," volume ii. 1836, pages 417, 425, and male. 
I3& Dr. Giinther informs roe that the !»" The Am. Naturalisii" April i87i,p. njjb 

CHAP. xii.J FISHES. 35 1 

The male, as Dr. Glinther 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 inch 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. peroniij the male has a 
brush like that possessed by the female of the last species, while 
the sides of the tail in the female are smooth. In some other 
species of the same genus the tail can be perceived to be a 
little roughened in the male and perfectly smooth in the female ; 
and lastly, in others both sexes have smooth sides. 

The males of many fish fight for the possession of the females. 
Thus the male stickleback {^Gasterosteus leiurus) has been de- 
scribed as "mad with delight " when the female comes out of 
her hiding-place and surveys the nest which he has made for 
her. '' He darts round her in every direction, then to his 
accumulated materials for the nest, then back again in an in- 
stant ; and as she does not advance he endeavors to push her 
with his snout, and then tries to pull her by the tail and side- 
spine to the nest." ^ The males are said to be polygamists ; ^ 
they are extraordinarily bold and pugnacious, while " the 
females are quite pacific." Their battles are at times des- 
perate ; "for these puny combatants 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 while fighting swim 
round and round each other, biting and endeavoring 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 eflfect 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 con- 
quered, " his gallant bearing forsakes him ; his gay colore 
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, Superintendent of 

• See Mr. R. Warington's interesting * Noel Humphreys, " River Gardens," 

articles in "The Annals and Magazine of 1857. 

Natural History," October 1852, and No- * Loudon's " Mag. of Nat. History," voU 

veinber 1855. iii. 1830, p. 331. 



[part It, 

Fisheries, informs me that he has often watched from the bridge 
at Perth the males driving away their rivals, while the females 
were spawning. The males '' are constantly fighting and tear- 
ing each other on the spawning-beds, and many so injure ca( h 
other as to cause the death of numbers, many being seen swim- 
ming 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 Xyne and found about 300 dead salmon. 

Fig. 27. — Head of male common salmon [Salnto salar) during the breeding-season 

[This drawing, as well as all the others in the present chapter, have been executed by the 
well-known artist, Mr. G. Ford, from specimens in the British Museum, under the kind 
superintendence of Dr. Giinther.] 

all of which with one exception were males ; and he was con- 
vinced 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 color, ''the 
lower jaw elongates, and a cartilaginous projection turns up- 
ward from the point, which, when the jaws are closed, oc- 
cupies 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 

« "The Field," June 29, 1867. For Mr. remarks that, like the stag, the male would, 

Shaw's statement, see ''Edinburgh Re- if he could, keep all other males away, 

view," 1843. Another experienced observer ^ Yarrell, " History of British Fisfces^'* 

(3crope's " Days of Salmon Fishing," p. to) vol. ii. 1836, p. 10, 


Salmo lycaodon of N.-W. A.merica 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 the teeth grow into regular fangs, often more 
than half an inch in length. With the European salmon, ac- 
cording to Mr. Lloyd,'-^ the temporary hook-like structure 
serves to strengthen and protect the jaws, when one male 

Pig. 28.— Head of female salmon, 

charges another with wonderful violence ; but the greatly de- 
veloped teeth of the male American salmon may be compared 
with the tusks of many male mammals, and they indicate an 
offensive rather than a protective purpose. 

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 {Rata clavaf) the adult male has sharp-pointed 
teeth, directed backward, while those of the female are broad 

• "The Naturalist in Vancouver's Isl- » "Scandinavian Adventures," voL \, 
and," vol. i. 1866, p. 54. 1854, pp. loo, 104. 

354 TtfE DESCENT OF MAN. [part u 

and flat, and form a pavement ; so that these teeth differ in the 
two sexes of the same species more than is iisnal in distinct 
genera of the same family. The teeth of the male become 
sharp only when he is adult : while young they are broad and 
flat like those of the female. As so frequently occurs with 
secondary sexual characters, both sexes of some species of rays 
(for instance i?. batis), when adult, possess sharp-pointed teeth ; 
and here a character, proper to and primarily gained by the 
male, appears to have been transmitted to the offspring of both 
sexes. The teeth are likewise pointed in both sexes of R. 
maaiiata, 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 Ihose of the mature 
females of the above-mentioned species. ^^ As the rays are 
bold, strong, and voracious fish, we may suspect that the males 
require their sharp teeth for fighting with their rivals ; but as 
they possess many parts modified and adapted for the prehen- 
sion of the female, it is possible that their teeth may be used 
for this purpose. 

In regard to size, M. Car bonnier ^^ 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 actu- 
ally 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 
"^iable 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 v/ith 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 

*<> See Yarrell's account of the rays in his 1* As quoted in "The Fanner," 1868, pi 
" Hist, of British Fishes," vol. ii. 1836, p. 369. 
416, with an excellent figure, and p. 422, 433. 




colors ; or these are much brighter in the male than in the fe- 
male. 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 sure the tail feathers to the peacock. I 
am indebted for most of the following facts to the kindness of 
Dr. Giinther. There is rrason to suspect that many tropical 
fishes differ sexually in color and structure ; and there are 
some striking cases with our British fishes. The male Callio* 

Fig. 29.— Callionymus lyra. Upper figure, male ; lower figure, fenuta, 
N.B. The lower figure is more reduced than the upper. 

nymus lyra has been called the gcmmeous dragonet " froni its 
brilliant, gem-like colors." 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 axe pale brown with 
dark longitudinal bands; the ventral, caudal, and anal fins 
being bluish-black. The female, or sordid dragonet, was con- 
sidered by Linnteus, and by many subsequent naturalists, as r 
distinct species; it is ol a dingy reddish-brown, with the da 
$»l fin brown and the other fins white. The sexes differ al|0 



[part It 

in the proportional size of the I'^ad and mouth, and in the po- 
sition of the eye ; ^'^ but the most striking difference is the ex- 
traordinary elongation in the, male (fig. 29) of the dorsal fin. 
Mr. W. Saville Kent remar^Ls that this ''singular appendage 
appears from my observatit)ns 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 purpose of fascinating their mates." ^^ The young males 
resemble the adult females in structure and color. Through- 

FiG. 30. — Xiphophorus Hellerii. Upper figure, male ; lower figure, female. 

out the genus Gallionymus/'* 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 

The male of the Coitus scorpius, or sea-scorpion, is slen- 
derer and smaller than the female. There is also a great dif- 
ference in color between them. It is difficult, as Mr. Lloyd ^^ 
remarks, ''for anyone who has not seen this fish during the 
spawning-season, when its hues are brightest, to conceive the 
admixture of brilliant colors with which it, in other respects so 

" I have drawn up this description from British Museum," by Dr. Giinther, 1861, pp. 

Yarrell's ''British Fishes," vol. i. 1836, pp. 138-151. 
.*6i and 266. ^^ "Game Birds of Sweden," etc., 1867 

•' "Nature," July 1873, p. 264. p. 466. 

.♦• •* Catalogue of Acanth, Fishes in the 


ill-favored, is at that time adorned.*' Both sexes of tlie Labrus 
mixttis, although very different in color, are beautiful ; the 
male being orange with bright blue stripe.;, and the female 
bright red with some black spots on the back. 

In the very distinct family of the Cyprinodontidae — inhabi- 
tants of the fresh waters of foreign lands — the sexes sometimes 
differ much in various characters. In the male of the Moilien- 
esia peteneftsis,^^ the dorsal iin is greatly de\'cloped and is 
marked with a row of large, round, ocellated, bright-colored 
spots ; while the same fin in the female is smaller, of a dif- 
ferent shape, and marked only with irregularly curved broA\n 
spots. In the male the basal margin of the anal fin is also a 
little produced and dark colored. In the male of an allied 
form, the XipJiophorus Ilellern (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 colors. This 
filament does not contain any muscles, and apparently cannot 
be of any direct use to the fish. As in the case of the Callio- 
nymus, the males while young resemble the adult females in 
color and structure. Sexual differences such as these may be 
strictly compared with those which are so frequent with gal- 
linaceous birds. ^''' 

In a siluroid fish, inhabiting the fresh waters of Soi;th Amer- 
ica, the Plecostonius bardatus^^ (fig. 31), the rnale 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 tentacles project from the front \.<ax\. of the head 
of the male, which are absent in the female. These tentacles 
are prolongations of the true skin, and therefore are not homo- 
logous 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 Chi?nccra 
monsfrosa, the male has a hook-shaped bone on the top of 
the head, directed forward, with its end rounded and covered 
with sharp spines; in the female *' this crown is altogether ab^ 

*• With respect to this and the following ^' Dr. Giinther makes this rem«j-h 

species I am indebted to Dr. Giinther for in- '* Catalogue of Fishes in the Uritish Mu5 ?■ 

formation : see also his paper on the " Fish- urn," vol. iii. 1861, p. 141. 
cs of Central America," in "Transact. '" See Dr. Giinther on this genus, #5 

Zfidog. Soc."voI. vi. x868, p. 485. "Proc. Zoolog. Soc" i868, p. 33a. 




f^Q, jt.— Plecostomus batbatws- Tjpper figure, head of ma« ; lower figure, feotfCi 

ttiAp. xii.] PisitES. 359 

sent," but w1k»1 i's use may be to the male is utterly un- 
known. ^^ 

The structures as yet referred to are permanent in the male 
after he has arrived at maturity; but with some Blennies, and 
in another allied genus, -^ 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 colored. There can be 
little doubt that this crest serves as a temporary sexual orna- 
ment, 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 species neither sex is thus provided. In many of 
the Chromidce, for instance in Geophagus and especially in 
Cichla, the males, as I hear from Prof. Agassiz,^^ have a con- 
spicuous protuberance on the forehead which is wholly want- 
ing in the females and in the young males. Prof. Agassiz 
adds, *' I have often observed these fishes at the time of spawn- 
ing when the protuberance is largest, and at other seasons 
when it is totally wanting, and the two sexes show no differ- 
ence 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 whethef 
they serve as ornaments must remain at present doubtful. 

I hear from Prof. Agassiz and Dr. Giinther, that the males 
of those fishes which differ permanently in color from the fe- 
males, often become more brilliant during the breeding -sea- 
son. This is likewise the case with a multitude of fishes, the 
sexes of which are identical in color at all other seasons of the? 
year. The tench, roach, and perch may be given as instance.>o 
The male salmon at this season is '' marked on the cheeks wit^i 
^^range-colored stripes, which give it the appearance of a 
Labrus, and the body partakes of a golden-orange tinge. TIi? 
females are dark in color, and are commonly called black- 
fish." "^ An analogous and even greater change takes place 
with the Salmo eriox or bull trout ; the males of the char [S, 
iimbla) are likewise at this season rather brighter in color than 
the female? ^ The colors of the pike (^Esox recticulatus) of 

'9 F. Buckland, iii "Land and Water," 2» See also "A Journey in Brazil," 

July 1868, p. 377, with a figure. Many by Prof, and Mrs. Agassiz, 1868, p. 220. 

other cases could be added of structures ^a Yariell, " British Fishes," vol. il. 1836, 

peculiar to the male, of which the uses are pp. 10, 12, 35. 

not known. as \v. Thompson, in " Annals and Mae. 

20 Dr. Giinther, " Catalogue of Fishes." of Nat. History," voU vi. 1841, p. 440. 
vol "* 00. 221 and 240. 

^60 THE DESCENT OF MAN". [part il ' 

the United States, especially of the male, become, during the 
breeding-scaison, exceedingly intense, brilliant, and iridescent.'^ 
Another striking instance out of many is afforded by the male 
stickleback {^Gasterostcus 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 appeal's as though it were somewhat translucent and glowed 
with an internal incandescence." After the breeding-season 
these colors all change, the thro.?.t and belly become of a paler 
ted, 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 Labnts mixfus, which, as we have seen, 
differs in color from the female, makes '' a deep hollow in the 
sand of the tank, and then endeavors, in the most persuasive 
manner, to induce a female of the same species to share it with 
him, swimming backward and forward between her and the 
completed nest, and plainly exhibiting the greatest anxiety for 
her to follow." The males of Cantharus lifieatus become, dur- 
ing the breeding-season, of deep leaden-black ; they then re- 
tire 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. Toward his companions of the opposite sex his 
conduct is far different ; many of the latter are now distended 
with spawn, and these he endeavors by all the means in his 
power to lure singly to his prepared hollow, and there to de- 
posit the myriad ova with which they are laden, v/hicli 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. Car- 
bonnier, who carefully observed these fishes under confine- 
ment.^' The males are most beautifully colored, more so than 
the females. During the breeding-season they contend for 
the possession of the females ; and, in the act of courtship, ex- 

»* "The American Agriculturist," 1868, p. ^" *' Nature," May, 1873, p. 25. 
100, '^'' " Bull, de la Soc. d'Acclimat." Paris, 

a* "Annals and Mag, of Nat Hist" Oct July, 1869, and Jan., t6^o, 


pand their fins, which are spotted c*nd ornamented with 
brightly-colored 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 dc 
leurs vives couleurs chercher a attirer 1' attention des femelles, 
lesquelles ne paraissaient indifferentes a ce manege, ellcs 
nageaient avec une moUe lenteur vers les males et semblaicnt 
se complaire dans leur voisinage. ' ' After the male has won 
his bride, he makes a little disk of froth by blowing air and 
mucus out of his mouth. He then collects the fertilized ova 
dropped 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 disk of 
froth, afterward guarding them, repairing the froth, and taking 
care of the young when hatched. I mention these particulars, 
because, as we shall presently see, there are fishes, the males of 
which hatch their eggs in their mouths ; and those who do not 
believe in the principle of gradual evolution might ask how 
wuld such a habit have originated ; but the difficulty is much 
iiminished when we know that there are fishes which thus col- 
lect and carry the eggs ; for, \i delayed by any cause in deposit- 
ing 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 fertilize the ova except in the presence of the females. 
The males fight for the possession of the females. In many 
species, the males while young resemble the females in color ; 
but when adult become much more brilliant, and retain their 
colors throughout life. In other species the males become 
brighter than the females and otherwise more highly orna- 
mented, only during the season of love. The males sedulously 
court the females, and in one case, as we have seen, take pains 
in displaying their beauty before them. Can it be believed 
that they would thus act to no purpose during their courtship ? 
And this would be the case unless the females exert some choice 
and select those males which please or excite them most. If 
the female exerts such choice, all the above facts on the orna- 
mentation of the males become at once intelligible by the aid 
of sexual selection. 

We have next to inquire whether this view of the bright 
colors of certain male fishes having been acquired through 

CP)— Vol. 3 


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 (Z. pavo), described, ^ with 
pardonable exaggeration, as formed of polished scales of gold, 
incrusting lapis-lazuli, rubies, sapphires, emeralds, and ame- 
thysts — 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 color. With some fishes, as with many 
of the lowest animals, splendid colors 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-^"h 
{Cyprinus auratus), judging from the analogy of the goldt.^ 
variety of the common carp, is perhaps a case in point, as it 
may owe its splendid colors to a single abrupt variation, due 
to the conditions to which this fish has been subjected under 
confinement. It is, however, more probable that these colors 
have been intensified through artificial selection, as this species 
has been carefully bred in China from a remote period. ^^ Un- 
der natural conditions it does not seem probable that beings so 
highly organized as fishes, and which live under such complex 
relations, should become brilliantly colored without suffer- 
ing some evil or receiving some benefit from so great a 
change, and consequently without the intervention of natural 

What, then, are we to conclude in regard to the many fishes 
both sexes of which are splendidly colored ? , Mr. Wallace ^ 
believes that the species which frequent reefs, where corals and 
other brightly colored organisms abound, are brightly colored 
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 
colored corals or other organisms for the fishes to resemble ; 
yet many species in the Amazons are beautifully colored, and 

•* Bory de Saint Vincent, in " Diet. Class, a.d. 960. In the year 1129 these fishes 

d'Hist. Nat." torn. ix. 1826, p. 151. abounded. In another place it it. said that 

2» Owing to some remarks on this subject, since the year 1548 there has been "pro- 
made in my work " On the Variation of An- duced at Hangchow a variety called the fire- 
imals under Domestication," Mr. W. F. fish, from its intensely-red color. It is uni- 
Mayers ("Chinese Notes and Queries," versally admired, and there is not a house- 
Aug., 1868, p. 113) has searched the ancient hold where it is not cultivated, /« rivalry 
Chinese encyclopaedias. He finds that gold- as to its color and as a source of profi'.." 
ish were first reared in confinement dur- 30 "Westminster Review," July, 1867, 
fiag the Sung Dynastyj which commenced p. 7. 


many of the carnivorous Cyprinidae in India are ornamented 
with " bright longitudinal lines of various tints."'^ Mr. McClel- 
land, in describing these fishes, goes so far as to suppose that 
*' the peculiar brilliancy of their colors " serves as " a better 
mark for kingfishers, 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 pos- 
sible that certain fishes may have been rendered conspicuous in 
order to warn birds and beasts of prey that they were un- 
palatable, 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 colored, is that their colors 
were acquired by the males as a sexual ornament, and were 
transferred equally, or nearly so, to the other sex. 

We have now to consider whether, when the male differs in 
a marked manner from the female in color or in other orna- 
ments, he alone has been modified, the variations being in- 
herited by his male offspring alone ; or whether the female 
has been specially modified and rendered inconspicuous for the 
sake of protection, such modifications being inherited only by 
the females. It is impossible to doubt that color has been 
gained by many fishes as a protection : no one can examine 
the speckled upper surface of a flounder, and overlook its re- 
semblance to the sandy bed of the sea on which it lives. Cer- 
tain fishes, moreover, can, through the action of the nervous 
system, change their colors in adaptation to surrounding ob- 
jects, and that within a short time.^ One of the most striking 
instances ever recorded of an animal being protected by its 
color (as far as it can be judged of in preserved si^ecimens), as 
well as by its form, is that given by Dr. Giinther ^ of a pipe- 
fish, which, with its reddish streaming filaments, is hardly disv 
tinguislv»ble from the sea-weed to which it clings with its pre- 
hensile tail But the question now under consideration is 
whether the females alone have been modified for this object. 
We can see that one sex will not be modified through natural 
selection for the sake of protection more than the other, sup- 
posing both *^o vary, unless one sex is exposed for a longer 

•> " Indian Cyprinidae," by Mr. J. McClel- •' G. Pouchet, L'Institiit, Nov. i,'7i, p. 134. 
land, "Asiatic Researches,* voL xix. part " " Proc. Zoolog. Soc." 1865, p. 327, pL 
S* 18391 P* a''*' xiv. 9nd xv. 

364 THE DESCENT OF MAN. [part it 

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 differ- 
ence, the males, from being generally smaller and from wander 
ing more about, are exposed to greater danger than the females ; 
and yet, when the sexes differ, the males are almost always the 
more conspicuously colored. The ova are fertilized immedi- 
ately 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 
fertilized 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 colored individuals of either sex would 
be equally liable to be destroyed or preserved, and both 
would have an equal influence on the colors of their offspring. 

Certain fishes, belonging to several families, make nests, and 
some of them take care of their young when hatched. Both 
sexes of the bright-colored Crefiilabrus massa and inelops worV 
together in building their nests with sea- weed, shells, etc.* 
But the males of certain fishes do all the work, and afterward 
take exclusive charge of the young. This is the case with the 
dull-colored gobies,^ in which the sexes are not known to 
differ in color, and likewise with the sticklebacks (Gasterosteus), 
in which the males become brilliantly colored during the 
spawning season. The male of the sniooth-tailed stickleback 
(G^. leiurus) performs the duties of a nurse with exemplary 
care and vigilance during a long time, and is continually em- 
ployed in gently leading back the young to the nest, when they 
stray too far. He courageously drives away all enemies, in- 
cluding 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 ex- 
traordinary habit of hatching, within their mouths or branchial 
cavities, the eggs laid by the females.^ I am informed by 

'* Yarrell, "British Fishes," vol. ii. p. it. '' See Mr. Warington's most interesting 

'* According to the observations of M. description of the habits of the Gasteroxteus 

Gerbc ; see Giinther's "Record of Zoolog. leiurus, in "Annals and Mag. of Nat. 

Literature," 1865, p. 194. Hist." November, 1855. 

'* Cuvier, " Rfegne Animal," vol. ii. 1829, 3* Prof. Wyman, in " Proc. Boston See 

^ 343. of Nat. Hist." Sept. 15, 1857. Also Pro£ 


Prof. Agassiz that the males of the Amazonian species which 
follow this habit, "not only are generally brighter than the 
females, but the difference is greater at the spawning season 
than at any other time." The species of Geophagus act in the 
same manner ; and in this genus a conspicuous protuberance 
becomes developed on the forehead of the males during the 
breeding season. With the various species of Chromids, as 
Prof. Agassiz likewise informs me, sexual differences in 
color may be observed, ''whether they lay their eggs in the 
water among aquatic plants or deposit them in holes, leaving 
them to come out without further care, or build shallow nests 
in the river mud, over which they sit, as our Pomotis does. 
It ought also to be observed that these sitters are among the 
brightest species in their respective families ; for instance, 
Hygrogonus is bright green, with large black ocelli, encircled 
with the most brilliant red." Whether with all the species of 
Chromids it is the male alone which sits on the eggs is not 
known. It is, however, manifest that the fact of the eggs being 
protected or unprotected by the parents has had little or no 
influence on the differences in color between the sexes. It is 
further manifest, in all the cases in which the males take ex- 
clusive charge of the nests and young, that the destruction of 
the brighter colored males would be far more influential on 
the character of the race than the destruction of the brighter 
colored 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 colored than 
the females. 

In most of the Lophobranchii (Pipe-fish, Hippocampi, etc.) 
the males have either marsupial sacks or hemispherical depres- 
sions on the abdomen, in which the ova laid by the female are 
hatched. The males also show great attachment to their 
young.^ The sexes do not commonly differ much in color; 
but Dr. Giinther 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 colored and spotted than the male, and she alone has a 
marsupial sack and hatches the eggs ; so that the female of 

Turner, in "Journal of Anatomy and Phys." «> Dr. Gunther, since publishing an ^c 

Nov. I, 1866. p. 78. Dr. Giinther has like- count of this species in "The Fishes ofZan- 

wise described other cases. ^ zibar," by Col. Plavfair, 1866, p. 137. has r& 

Yarrell, " Hist, of British Fishes," vol. examined the specimens, and has given mo 

n« S836, pp. 329, 338. the above information. 

366 THE DESCEI^T OF AfAl^T, (PARt *' 

Solenostoma differs from all the other Lophobranchii in this 
iatter respect, and from almost all other fishes, in being more 
brightly colored than the male. It is imjjrobable that this re- 
markable 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 colored 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 colors of that sex, which 
is the more important of the two fcr the welfare of the off- 
spring, must be in some manner protective. But from the 
large number of fishes of which the males are either perma- 
nently or periodically 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 tbe 
probable explanation, namely, that ihe males have selected the 
more attractive females, instead of the latter having selected, in 
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 color or in other ornamental charac- 
ters, the males originally varied, with their variations trans- 
mitted to the same sex, and accumulated through sexual selec- 
tion by attracting or exciting the females. In many cases, 
however, such chaiacters have been transferred, either partially 
or completely, to the females. In other cases, again, both sexes 
have been colored alike for the sake of protection ; but in no 
instance does it appear that the female alone has had her 
colors or other characters specially modified for this latter pur- 

The last point which need be noticed is that fishes are 
known to make various noises, some of which are described as 
being musical. Dr. Dufosse, who has especially attended to 
this subject, says that the sounds are voluntarily produced in 
several ways by different fishes : by the friction of the pharyn- 
geal bones — by the vibration of certain muscles attached to 
the swim-bladder, which serves as a resounding board — and by 
the vibration 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 in* 

CHAP. Xll.) 



teresting 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 drum- 
ming of the Umbrinas in the European seas is said to be audi- 
ble 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 Vertebrata, as with so many in- 
sects and spiders, sound-producing instruments have, at least in 
some cases, been developed through sexual selection, as a 
means for bringing the sexes together. 


Urodela. — I will begin with the tailed amphibians. The 
sexes of salamanders or newts often differ much both in color 

Rg. 32.— Triton cristatus (half natural size, from Bell's "British Reptiles"). Uppct 
hgure, male during the breeding season ; lower figure, female. 

and Structure. In some species prehensile claws are developed 
on the fore-legs of the males during the. breeding season : ,' ^nd 

p Vs3 ^S"lvii"?8^8''o'^oT- "t'- ^^f' *'1^°'^''=^ tra^islation of this work (vol. ii. p. 
|aii than drumming. Dr. ZouifVwn, in v- »°7o, p. 40, - _. 


at this season in the male Triton palmipcs the hind feet are pro- 
vided with a swimming-web, which is ahiiost completely ab- 
sorbed during the winter ; so that their feet then resemble those 
of the female.*^ This structure no doubt aids the male in his 
t?ager search and pursuit of the female. While courting her he 
rapidly vibrates the end of his tail. With our common newts 
(^Triton punctatus zxiA cristatus) a deep, much indented crest 
is developed along the back and tail of the male during the 
breeding season, which disappears during the winter. Mr. St. 
George Mivart informs me that it is not furnished with muscles, 
and therefore cannot be used for locomotion. As during the 
season of courtship it becomes edged with bright colors, there 
can hardly be a doubt that it is a masculine ornament. In 
many species the body presents strorgly contrasted, though 
lurid tints, and these become more vwid during the l)reeding 
season. The male, for instance, of our common little newt 
{Triton punctatus) is '' brownish - gray above, passing into 
yellow beneath, which in the .spring becomes a rich bright 
orange, marked everywhere with round dark spots." The edge 
of the crest also is then tipped with bright red or violet. Tne 
female is usually of a yellowish-brown color with scattered 
brown dots, and the lower surface is often quite plain.'** The 
young are obscurely tinted. The ova are fertihzed 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 colors and ornamental append- 
ages through sexual selection ; these being transmitted either 
to the male offspring alone, or to both sexes. 

Anura or Batrachia. — With many frogs and toads the colors 
evidently serve as a protection, such as the briglit green tints 
of tree frogs and the obscure mottled shades of many ^errestrial 
species. The most conspicuously coloie^i toad which I ever 
saw, the Phryniscus nigricans J^^ \\z.i± iflr- Nv'nole upper surface of 
the body as black as ink, with the boir>e of the feet and parts of 
the abdomen spotted with the brightest vermilion. It cravvled 
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 
passing creature. These colors are probably beneficial by- 
making this animal known to all birds of prey as a nauseous 

*3 Bell, "History of British Reptiles," ""Zoology of the Voyage of the'B«tf 
2d edit. 1849, pp. 156-139, gle,' " 1843. B^IU ibi4< p. 49^ 

4* Ibid., pp. 146. 151. 


In Nicaragua there is a little frog '^ dressed in a bright liver)^ 
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 color. Dr. Gunther 
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 sur- 
prising that these animals have not acquired more strongly 
n.vked sexual characters ; for, though cold-blooded, their pas- 
sions are strong. Dr. Gunther informs me that he has several 
tinies found an unfortunate female toad dead and smothered 
from having been so closely embraced by three or four males. 
Frogs have been observed by Prof. 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 miioic, when applied to the discordant and over^^'llelm- 
ing sounds emitted by male bull-frogs and some other spe- 
cies, seems, according to our taste, a singularly inappropriate 
expression. Nevertheless, certain frogs sing in a decidedly 
plea^^ing manner. Near Rio Janeiro I used often to sit in the 
evening to listen to a number of little Hykie, 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 developed than 
those of the females. In some genera the males alone are pro- 
vided with sacs which open into the larynx."*^ For instance, in 

^^ "The Naturalist in Nicaragua," 1874, gers, which perhaps subserve the same end 

P- 321- as the above mentioned prominences. 

♦^ The male alone of the i^M/i ,9//-/ww^;/- 49 r^u "History of British Reptiles," 

tis (Dr. Anderson, "Proc. Zoolog. Soc." 1849. p. 93. 

1871, p. 204) has two plate-like callosities on * ♦ J. Bishop, in " Todd's Cyclop, of AlUA 

tiie thorax and certain rugosities 00 the fin- and Phys." vol. iv. p. 1503. 


the edible frog {Rana csculcnta) *' the sacs arc peculiar to the 
males, and become, when filled with air in the act of croaking, 
large globular bladders, standing out one on each side of the 
head, near the corners of the mouth." The croak of the male 
is thus rendered exceedingly powerful, while 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 


Cheloftia. — 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 pictd) has claws on its front feet twice 
as long as those of the female ; and these are used when the 
sexes unite. ^^ With the huge tortoise of the Galapagos Islands 
(^Testudo nigra) the males are said to grow to a larger size than 
the females : during the pairing season, and at no other time, 
the male utters a hoarse bellowing noise, which can be heard at 
the distance of more than a hundred yards ; the female, on the 
other hand, never uses her voice. ^^ 

With the Testudo elcgans of India, it is said '' that the com- 
bats 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 color ; 
Ror do I know that the males fight together, though this is 
probable, for some kinds make a prodigious display before the 
females. Bartram ^^ describes the niale 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 ap Indian chief rehearsing his feats of war." 
During the season of love a musky odor is emitted by the 
submaxillary glands of the crocodile, and pervades their 

6" Bell, ibid. p. 112-114. ^^ Dr. Giinther, " Reptiles of British In- 

s^Mr. C. J. Mavnard, "The American dia," 1864, p. 7. 

N ituralist," Dec. i86f . p. 555. ^* " Travels through Carolina," etc, 1791, 

^'^ See my "Journal of Researches dur- p. 128. 

ing the Voyage of th^ ' Kengle,' " 1845, p. "^ Owen. " Anatomy of Vertebrates," vgV' 

CUA{>. XILj kEPTILES, 371 

Ophidia. — Dr. Giinther informs me that the males are always 
smaller than the females, and generally have longer and slen- 
derer tails ; but he knows of no other difference in external 
structure. In regard to color, he can almost always dis- 
tinguish the male from the female by his more strongly pro- 
nounced 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 rattlesnakes of North 
America, the male of which, as the keeper in the Zoological 
Gardens showed me, can at once be distinguished from the 
female by having more lurid yellow about its whole body. In 
South Africa the Bucephalus capensis presents an analogous 
difference, for the female ''is never so fully variegated with 
yellow on the sides as the male." ^^ The male of the Ir.dian 
Dipsas cynodon, on the other hand, is blackish-brown, with 
the belly partly black, while 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 female bronze-colored.^' No doubt 
the colors of some snakes are protective, as shown by the green 
tints of tree-snakes, and the various mottled shades of the 
species which live in sandy places ; but it is doubtful whether 
the colors 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 colored with 
extreme elegance. The colors of certain species are very differ- 
ent in the adult and young states.^ 

During the breeding season the anal scent-glands of snakes 
are in active function ; ^^ and so it is with the same glands in 
hzards, 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 
charnr. ':h^ 'emale, rather than to guide her to the spot where the 
male nr^ay be found. Male snakes, though appearing so slug- 
gish, are amorous ; for m.any have been observed crowding 
round the same female, and even round her dead body. They 
are not known to fight together from rivalry. Their intellect- 
ual 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 

*• Sir Andrew Smith, "Zoolog. of S. *" Dr. Stoliczka, " Journal of Asiatic Soc. 

Africa; Reptilia," 1849, pl- x. of Bengal," vol. xxxix. 1870, pp. 205, 211. 

'■f Dr. A. Giinther, "Reptiles of British s'' Owen, "Anatomy of Vertebrates," vot 

India." »»*•' "^^ 1864, pp. 304* 308. i. x866, p. 6ie. 

372 THE DESCENT OF MAN. Cpart ii. 

Philadelphia irforms me that some ?nakes which he kept, 
learned after four or five times to avoid a noose with which 
they were at first easily caught. An excellent ol)server in Cey- 
lon, Mr. E. Layard, saw ^ a cobra thrust its head through a 
narrow hole and swallow a toad. " With this encumbrance lie 
could not withdraw himself; finding this, he reluctantly dis- 
gorged the precious morsel, 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 learned, and the toad was seized by one leg, with- 
drawn, 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 j^ersons. Cobras kept together in the same cage 
appai'ently feel some attachment toward each other. ^^ 

It does not, however, follow, because snakes have some 
reasoning powder, strong passions, and mutual affection, that 
they should likewise be endowed with sufficient taste to admire 
brilliant colors in their partners, so as to lead to the adornment of 
the species through sexual selection. Nevertheless, it is difficult 
to account in any other manner for the extreme beauty of certain 
species ; for instance, of the coral-snakes of South America, 
which are of a rich red with black and yellow transverse bands. 
I well remember how much surprise I felt at the beauty of the 
first coral-snake which I saw gliding across a path in Brazil. 
Snakes colored in this peculiar manner, as Mr. Wallace states 
on the authority of Dr. Glinther,*'^ are found nowhere else in 
the world except in South America, and here no less than four 
genera occur. One of these, Elaps, is venomous ; a second 
and widely distinct genus is doubtfully venomous, and the two 
others are quite harmless. The species belonging to these dis- 
tinct genera inhabit the same districts, and are so like each 
other, that no one "■ but a naturalist would distinguish the 
harmless from the poisonous kinds." Hence, as Mr. Wallace 
believes, the innocuous kinds have probably acquired their colors 
as a protection, on the principle of imitation ; for they would 
naturally be thought dangerous by their enemies. The cause, 
however, of the bright colors of the venomous Elaps remains 
to be explained, and this may perhaps be sexual selection. 

«" " Rambles in Ceylon, " in "Annals and «* Dr. Giinther, " Reptiles of Bridsh In- 
Mag. of Nat Hist." 2d series, vol. ix. 1852, dia," 1864, p. 340. 
p. 333, *' " Westminster Rev." July i, 1867, p. 3a* 


Snakes produce other sounds besides hissing. The deadly 
Echis carinata has on its sides sonie oblique rows of scales of 
a peculiar structure with serrated edges ; and when this snake 
is excited, these scales are rubbed against each other, which 
produces *'a curious prolonged, almost hissing sound." ^ 
With respect to the rattling of the rattlesnake, we have at 
last some definite information : for Prof. Aughey states,^ 
that on two occasions, being himself unseen, he watched from 
a little distance a rattlesnake coiled up with head erect, which 
continued co rattle at short intervals for half an hour : and at 
last he saw another snake approach, and when they met they 
paired. Hence he is satisfied that one of the uses of the rattle 
is to bring the sexes together. Unfortunately he did not as- 
certain whether it was the male or the female which remained 
stationary and called for the other. But it by no means follows 
from the above fact that the rattle may not be of use to these 
snakes in other ways, as a warning to animals which would 
otherwise attack them. Nor can I quite disbelieve the several 
accounts which have appeared of their thus paralyzing their 
prey with fear. Some other snakes also make a distinct noise 
by rapidly vibrating their tails against the surrounding stalks 
of plants ; and I have mj^self heard this in the case of d- Tri- 
gonocephalus in South America. 

Lacertilia. — The males of some, probably of many, kinds of 
lizards fight together from rivalry. Thus the arboreal Anolis 
cristatellus of South America is extremely pugnacious : '' Dur- 
ing the spring and early part of the summer, two adult males 
rarely meet without a contest. On first seeing one another, 
they nod their heads up and down three or four times, and 
at the same time expanding the frill or pouch beneath the 
throat ; their eyes glisten with rage, and after waving their 
tails from side to side for a fev seconds, as if to gather 
energy, they dart at each other furiously, rolling over and 
over, and holding firmly with their teeth. The conflict 
generally ends in one of the combatants losing his tail, which 
is often devoured by the victor." The male of this species 
is considerably larger than the female ; ^ and this, as far as 
Dr. Glinther has been able to ascertain, is the general rule 
with lizards of all kinds. The males alone of the Cyrtodactlyliis 
rubidus of the Andaman Islands possesses pre-anal pores : and 

•s Dr. Anderson, " Proc. Zoolog. Soc." "Mr. N. L. Austen kept tlieee animala 
1871, p. 196. alive for a considerable time ; see " La^ljt 

•♦ "The American Naturalist," 1873, p. and Water," July, 1867, p. 9. 




these pores, judging from analogy, probably serve to emit an 


The sexes often differ greatly in various external characters. 

The male of the above-mentioned Anolis is furnished with a 

crest which runs along the back 
and tail, and can be erected at 
pleasure ; but of this crest the 
female does not exhibit a trace. 
In the Indian Cophatis ceylanica, 
the female has a dorsal crest, 
though much less developed than 
in the male ; and so it is, as Dr. 
Giinther informs me, with the 

Fig. 33.— Sitana minor. Male with the femalcS of many IgUanaS, Cha- 

^RcptTs'onX").''^ ^^'■°"' ^""'^'''' meleons, and other lizards. In 

some species, however, the crest 
is equally developed in both sexes, as in the Iguana tuberculata. 
In the genus Sitana, the males alone are furnished with a large 
throat-pouch (fig. '^'^, which can be folded up like a fan, and 
is colored blue, black, and red ; but 
these splendid colors are exhibited 
only during the pairing season. 
The female does not possess even 
a rudiment of this appendage. In 
the Anolis cristate llus, according 
to Mr. Austen, the throat-pouch, 
which is bright red marbled with 
yellow, is present in the female, 
though in a rudimental condition. 
Again, in certain other lizards, both 
sexes are equally well provided with 
throat-pouches. Here we see with