The Descent of Man (Darwin)

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THE


DESCENT OF MAN,


AND


SELECTION IN RELATION TO SEX.


BY

CHARLES DARWIN, M.A.,

FELLOW OF THE ROYAL SOCIETY, ETC.


With Illustrations.


NEW EDITION, REVISED AND AUGMENTED.


COMPLETE IN ONE VOLUME.


NEW YORK

D. APPLETON AND COMPANY,

549 AND 551 BROADWAY.

1875.

CONTENTS.

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Pages 1-4

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PART I.

THE DESCENT OR ORIGIN OF MAN.

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

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

5
CHAPTER II.
On the Manner of Development of Man from some Lower Form.

Variability of body and mind in man—Inheritance—Causes of variability—Laws of variation the same in man as in the lower animals—Direct action of the conditions of life—Effects of the increased use and disuse of parts—Arrested development—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

26
CHAPTER III.
Comparison of the Mental Powers of Man and the Lower Animals.

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

65
CHAPTER IV.
Comparison of the Mental Powers of Man and the Lower Animals
continued.

The moral sense—Fundamental proposition–The qualities of social animals—Origin of sociability—Struggle between opposed instincts—Man a social animal—The more enduring social instincts conquer other less persistent instincts—The social virtues alone regarded by savages—The self-regarding virtues acquired at a later stage of development—The importance of the judgment of the members of the same community on conduct—Transmission of moral tendencies—Summary

97
CHAPTER V.
On the Development of the Intellectual and Moral Faculties during Primeval and Civilised Times.

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

127
CHAPTER VI.
On the Affinities and Genealogy of Man.

Position of man in the animal series—The natural system genealogical—Adaptive characters of slight value—Various small points of resemblance between man and the Quadrumana—Rank of man in the natural system—Birthplace and antiquity of man—Absence of fossil connecting-links—Lower stages in the genealogy of man, as inferred, firstly from his affinities and secondly from his structure—Early androgynous condition of the Vertebrata—Conclusion

146
CHAPTER VII.
On the Races of Man.

The nature and value of specific characters—Application to the races of man—Arguments in favour of, and opposed to, ranking the so-called races of man as distinct species—Sub-species—Monogenists and polygenists—Convergence of character—Numerous points of resemblance in body and mind between the most distinct races of man—The state of man when he first spread over the earth—Each race not descended from a single pair—The extinction of races—The formation of races—The effects of crossing—Slight influence of the direct action of the conditions of life—Slight or no influence of natural selection—Sexual selection

166





PART II.
SEXUAL SELECTION.
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CHAPTER VIII.
Principles of Sexual Selection.

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

207
CHAPTER IX.
Secondary Sexual Characters in the Lower Classes of the Animal Kindgom.

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

260
CHAPTER X.
Secondary Sexual Characters of Insects.

Diversified structures possessed by the males for seizing the females—Differences between the sexes, of which the meaning is not understood—Difference in size between the sexes—Thysanura—Diptera—Hemiptera—Homoptera, musical powers possessed by the males alone—Orthoptera, musical instruments of the males, much diversified in structure; pugnacity; colours—Neuroptera sexual differences in colour—Hymenoptera, pugnacity and colours—Coleoptera, colours; furnished with great horns, apparently as an ornament; battles; stridulating organs generally common to both sexes

274
CHAPTER XI.
Insects, continued.—Order Lepidoptera.
(butterflies and moths.)

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

307
CHAPTER XII.
Secondary Sexual Characters of Fishes, Amphibians, and Reptiles.

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

330
CHAPTER XIII.
Secondary Sexual Characters of Birds.

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

358
CHAPTER XIV.
Birdscontinued.

Choice exerted by the female—Length of courtship—Unpaired birds—Mental qualities and taste for the beautiful—Preference or antipathy shewn by the female for particular males—Variability of birds—Variations sometimes abrupt—Laws of variation—Formation of ocelli—Gradations of character—Case of Peacock, Argus pheasant, and Urosticte

404
CHAPTER XV.
Birdscontinued.

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

444
CHAPTER XVI.
Birdscontinued.

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 colouring—Conspicuously-coloured birds—Novelty appreciated—Summary of the four chapters on birds

463
CHAPTER XVII.
Secondary Sexual Characters of Mammals.

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

500
CHAPTER XVIII.
Secondary Sexual Characters of Mammalscontinued.

Voice—Remarkable sexual peculiarities in seals—Odour—Development of the hair—Colour of the hair and skin—Anomalous case of the female being more ornamented than the male—Colour and ornaments due to sexual selection—Colour acquired for the sake of protection—Colour, though common to both sexes, often due to sexual selection—On the disappearance of spots and stripes in adult quadrupeds—On the colours and ornaments of the Quadrumana—Summary

525





PART III.
SEXUAL SELECTION IN RELATION TO MAN,

AND CONCLUSION.

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CHAPTER XIX.
Secondary Sexual Characters of Man.

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

556
CHAPTER XX.
Secondary Sexual Characters of Mancontinued.

On the effects of the continued selection of women according to a different standard of beauty in each race—On the causes which interfere with sexual selection in civilised and savage nations—Conditions favourable to sexual selection during primeval times—On the manner of action of sexual selection with 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—Colour of the skin—Summary

585
CHAPTER XXI.
General Summary and Conclusion.

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

606




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620

PREFACE TO THE SECOND EDITION.


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During the successive reprints of the first edition of this work, published in 1871, I was able to introduce several important corrections; and now that more time has elapsed, I have endeavoured to profit by the fiery ordeal through which the book has passed, and have taken advantage of all the criticisms which seem to me sound. I am also greatly indebted to a large number of correspondents for the communication of a surprising number of new facts and remarks. These have been so numerous, that I have been able to use only the more important ones; and of these, as well as of the more important corrections, I will append a list. Some new illustrations have been introduced, and four of the old drawings have been replaced by better ones, done from life by Mr. T. W. Wood. I must especially call attention to some observations which I owe to the kindness of Prof. Huxley (given as a supplement at the end of Part I.), on the nature of the differences between the brains of man and the higher apes. I have been particularly glad to give these observations, because during the last few years several memoirs on the subject have appeared on the Continent, and their importance has been, in some cases, greatly exaggerated by popular writers.

I may take this opportunity of remarking that my critics frequently assume that I attribute all changes of corporeal structure and mental power exclusively to the natural selection of such variations as are often called spontaneous; whereas, even in the first edition of the 'Origin of Species,' I distinctly stated that great weight must be attributed to the inherited effects of use and disuse, with respect both to the body and mind. I also attributed some amount of modification to the direct and prolonged action of changed conditions of life. Some allowance, too, must be made for occasional reversions of structure; nor must we forget what I have called "correlated" growth, meaning, thereby, that various parts of the organisation are in some unknown manner so connected, that when one part varies, so do others; and if variations in the one are accumulated by selection, other parts will be modified. Again, it has been said by several critics, that when I found that many details of structure in man could not be explained through natural selection, I invented sexual selection; I gave, however, a tolerably clear sketch of this principle in the first edition of the 'Origin of Species,' and I there stated that it was applicable to man. This subject of sexual selection has been treated at full length in the present work, simply because an opportunity was here first afforded me. I have been struck with the likeness of many of the half-favourable criticisms on sexual selection, with those which appeared at first on natural selection; such as, that it would explain some few details, but certainly was not applicable to the extent to which I have employed it. My conviction of the power of sexual selection remains unshaken; but it is probable, or almost certain, that several of my conclusions will hereafter be found erroneous; this can hardly fail to be the case in the first treatment of a subject. When naturalists have become familiar with the idea of sexual selection, it will, as I believe, be much more largely accepted; and it has already been fully and favourably received by several capable judges.


Down, Beckenham, Kent,

September 1874.

TABLE

OF THE

PRINCIPAL ADDITIONS AND CORRECTIONS TO THE PRESENT EDITION.

First
Edition
Vol. I.
Present
Edition.

Page Page
22 15-17 Discussion on the rudimentary points in the human ear revised.
26 19 Cases of men born with hairy bodies.
27, note. 20, note. Muntegazza on the last molar tooth in man.
29 23 The rudiments of a tail in man.
32, note. 24, note. Bianconi on homologous structures, as explained by adaptation on mechanical principles.
40 70 Intelligence in a baboon.
42 71 Sense of humour in dogs.
44 72-3 Further facts on imitation in man and animals.
47 75 Reasoning power in the lower animals.
50 80 Acquisition of experience by animals.
53 83 Power of abstraction in animals.
58 88-9 Power of forming concepts in relation to language.
64 92 Pleasure from certain sounds, colours, and forms.
78 104 Fidelity in the elephant.
79 104 Galton on gregariousness of cattle.
81 105-6 Parental affection.
90, note. 112-113, note. Persistence of enmity and hatred.
91 114 Nature and strength of shame, regret, and remorse.
94 117, note. Suicide amongst savages.
97 120, note. The motives of conduct.
112 28 Selection, as applied to primeval man.
122 35-6 Resemblances between idiots and animals.
124, note. 39, note. Division of the malar bone.
125, note. 36-8, note. Supernumerary mammæ and digits.
128-9 41-2 Further cases of muscles proper to animals appearing in man.
146 55, note. Broca: average capacity of skull diminished by the preservation of the inferior members of society.
Page Page
149 57 Belt on advantages to man from his hairlessness.
150 58-9 Disappearance of the tail in man and certain monkeys.
169 134-5 Injurious forms of selection in civilised nations.
180 143 Indolence of man, when free from a struggle for existence,
193 151 Gorilla protecting himself from rain with his hands.
208, note. 161, note. Hermaphroditism in fish.
209 163 Rudimentary mammæ in male mammals.
239 188-190 Changed conditions lessen fertility and cause ill-health amongst savages.
245 195-6 Darkness of skin a protection against the sun.
250 199-206 Note by Professor Huxley on the development of the brain in man and apes.
256 209-210 Special organs of male parasitic worms for holding the female.
275-6 224-5 Greater variability of male than female; direct action of the environment in causing differences between the sexes.
290 235 Period of development of protuberances on birds' heads determines their transmission to one or both sexes.
301 243-4 Causes of excess of male births.
314 254 Proportion of the sexes in the bee family.
315 255-6 Excess of males perhaps sometimes determined by selection.
327 264 Bright colours of lowly organised animals.
338 272 Sexual selection amongst spiders.
339 273 Cause of smallness of male spiders.
245 277 Use of phosphorescence of the glow-worm.
349 280 The humming noises of flies.
350 281 Use of bright colours to Hemiptera (bugs).
351 282 Musical apparatus of Homoptera.
354
359
284-5
288, note.
Development of stridulating apparatus in Orthoptera.
366 292-3 Hermann Müller on sexual differences of bees.
387 308 Sounds produced by moths.
397 315 Display of beauty by butterflies.
401 319 Female butterflies, taking the more active part in courtship, brighter than their males.
412 324-5 Further cases of mimicry in butterflies and moths.
417 326 Cause of bright and diversified colours of caterpillars.
First
Edition
Vol. II.
Present
Edition.

Page Page
2 331 Brush-like scales of male Mallotus.
14 341 Further facts on courtship of fishes, and the spawning of Macropus.
23 347 Dufossé on the sounds made by fishes.
26 349 Belt on a frog protected by bright colouring.
30 352 Further facts on mental powers of snakes.
32 353 Sounds produced by snakes; the rattlesnake.
36 357 Combats of Chameleons.
72 383 Marshall on protuberances on birds' heads.
91 398 Further facts on display by the Argus pheasant.
108 411 Attachment between paired birds.
118 417 Female pigeon rejecting certain males.
120 419 Albino birds not finding partners, in a state of nature.
124 423 Direct action of climate on birds' colours.
147-150 438-441 Further facts on the ocelli in the Argus pheasant.
152 443 Display by humming-birds in courtship.
157 446 Cases with pigeons of colour transmitted to one sex alone.
232 495-6 Taste for the beautiful permament enough to allow of sexual selection with the lower animals.
247 505 Horns of sheep originally a masculine character.
248 506 Castration affecting horns of animals.
256 513-4 Prong-horned variety of Cervus virginianus.
260 516 Relative sizes of male and female whales and seals.
266 521 Absence of tusks in male miocene pigs.
286 534 Dobson on sexual differences of bats.
299 542-3 Recks on advantage from peculiar colouring.
316 556 Difference of complexion in men and women of an African tribe.
337 572 Speech subsequent to singing.
356 586 Schopenhauer on importance of courtship to mankind.
359 et seq. 588 et seq. Revision of discussion on communal marriages and promiscuity.
373 598-9 Power of choice of woman in marriage, amongst savages.
380 603 Long-continued habit of plucking out hairs may produce an inherited effect.


This work was published before January 1, 1923, and is in the public domain worldwide because the author died at least 100 years ago.