# The Descent of Man (Darwin)

The Descent of Man, and Selection in Relation to Sex is the second edition of a book on evolutionary theory by British naturalist Charles Darwin. The first edition was published in 1871, and the second, enlarged edition in 1874 (this Wikisource edition is based on an unchanged reprint of the second edition). It followed his 1859 work, The Origin of Species, "[applying] evolutionary theory to human evolution, and details his theory of sexual selection, a form of biological adaptation distinct from, yet interconnected with, natural selection" Warning: template has been deprecated.
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.
PART I.
THE DESCENT OR ORIGIN OF MAN.
| CHAPTER I. The Evidence of the Descent of Man from some Lower Form. |
| Nature of the evidence bearing on the origin of 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. |
| 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 Kingdom. |
| 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. Birds—continued. |
| 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. Birds—continued. |
| 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. Birds—concluded. |
| The immature plumage in relation to the character of the plumage in both sexes when adult—Six classes of cases—Sexual differences between the males of closely-allied or representative species—The female 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 Mammals—continued. |
| 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. |
| 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 Man—continued. |
| On the effects of the continued selection of women according to a different standard of beauty in each race—On the causes which interfere with sexual selection in civilised and savage nations—Conditions favourable to sexual selection during primeval times—On the manner of action of sexual selection with 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 |
PREFACE TO THE SECOND EDITION.
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 EditionVol. 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. ​ |
| 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. |
| 345 | 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 EditionVol. 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, 1929, and is in the public domain worldwide because the author died at least 100 years ago.
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