The Descent of Man by Charles Darwin (children's ebooks online TXT) 📖

nie an diesem Thier bemerkt hatte. Beim Anblick dieses Gegenstandes erregte sich das Mannchen sichtlich, denn es polterte heftig an den Staben, ebenfalls gurgelnde Laute ausstossend.” As all the monkeys which have the hinder parts of their bodies more or less brightly coloured live, according to Von Fischer, in open rocky places, he thinks that these colours serve to render one sex conspicuous at a distance to the other; but, as monkeys are such gregarious animals, I should have thought that there was no need for the sexes to recognise each other at a distance. It seems to me more probable that the bright colours, whether on the face or hinder end, or, as in the mandrill, on both, serve as a sexual ornament and attraction. Anyhow, as we now know that monkeys have the habit of turning their hinder ends towards other monkeys, it ceases to be at all surprising that it should have been this part of their bodies which has been more or less decorated. The fact that it is only the monkeys thus characterised which, as far as at present known, act in this manner as a greeting towards other monkeys renders it doubtful whether the habit was first acquired from some independent cause, and that afterwards the parts in question were coloured as a sexual ornament; or whether the colouring and the habit of turning round were first acquired through variation and sexual selection, and that afterwards the habit was retained as a sign of pleasure or as a greeting, through the principle of inherited association. This principle apparently comes into play on many occasions: thus it is generally admitted that the songs of birds serve mainly as an attraction during the season of love, and that the leks, or great congregations of the black-grouse, are connected with their courtship; but the habit of singing has been retained by some birds when they feel happy, for instance by the common robin, and the habit of congregating has been retained by the black- grouse during other seasons of the year.

I beg leave to refer to one other point in relation to sexual selection. It has been objected that this form of selection, as far as the ornaments of the males are concerned, implies that all females within the same district must possess and exercise exactly the same taste. It should, however, be observed, in the first place, that although the range of variation of a species may be very large, it is by no means indefinite. I have elsewhere given a good instance of this fact in the pigeon, of which there are at least a hundred varieties differing widely in their colours, and at least a score of varieties of the fowl differing in the same kind of way; but the range of colour in these two species is extremely distinct. Therefore the females of natural species cannot have an unlimited scope for their taste. In the second place, I presume that no supporter of the principle of sexual selection believes that the females select particular points of beauty in the males; they are merely excited or attracted in a greater degree by one male than by another, and this seems often to depend, especially with birds, on brilliant colouring. Even man, excepting perhaps an artist, does not analyse the slight differences in the features of the woman whom he may admire, on which her beauty depends. The male mandrill has not only the hinder end of his body, but his face gorgeously coloured and marked with oblique ridges, a yellow beard, and other ornaments. We may infer from what we see of the variation of animals under domestication, that the above several ornaments of the mandrill were gradually acquired by one individual varying a little in one way, and another individual in another way. The males which were the handsomest or the most attractive in any manner to the females would pair oftenest, and would leave rather more offspring than other males. The offspring of the former, although variously intercrossed, would either inherit the peculiarities of their fathers or transmit an increased tendency to vary in the same manner. Consequently the whole body of males inhabiting the same country would tend from the effects of constant intercrossing to become modified almost uniformly, but sometimes a little more in one character and sometimes in another, though at an extremely slow rate; all ultimately being thus rendered more attractive to the females. The process is like that which I have called unconscious selection by man, and of which I have given several instances. In one country the inhabitants value a fleet or light dog or horse, and in another country a heavier and more powerful one; in neither country is there any selection of individual animals with lighter or stronger bodies and limbs; nevertheless after a considerable lapse of time the individuals are found to have been modified in the desired manner almost uniformly, though differently in each country. In two absolutely distinct countries inhabited by the same species, the individuals of which can never during long ages have intermigrated and intercrossed, and where, moreover, the variations will probably not have been identically the same, sexual selection might cause the males to differ. Nor does the belief appear to me altogether fanciful that two sets of females, surrounded by a very different environment, would be apt to acquire somewhat different tastes with respect to form, sound, or colour. However this may be, I have given in my ‘Descent of Man’ instances of closely-allied birds inhabiting distinct countries, of which the young and the females cannot be distinguished, whilst the adult males differ considerably, and this may be attributed with much probability to the action of sexual selection.

INDEX.

Abbot, C., on the battles of seals.

Abductor of the fifth metatarsal, presence of, in man.

Abercrombie, Dr., on disease of the brain affecting speech.

Abipones, marriage customs of the.

Abortion, prevalence of the practice of.

Abou-Simbel, caves of.

Abramis brama.

Abstraction, power of, in animals.

Acalles, stridulation of.

Acanthodactylus capensis, sexual differences of colour in.

Accentor Modularis.

Acclimatisation, difference of, in different races of men.

Achetidae, stridulation of the; rudimentary stridulating organs in female.

Acilius sulcatus, elytra of the female.

Acomus, development of spurs in the female of.

Acridiidae, stridulation of the; rudimentary stridulating organs in female.

Acromio-basilar muscle, and quadrupedal gait.

Acting.

Actiniae, bright colours of.

Adams, Mr., migration of birds; intelligence of nut-hatch; on the Bombycilla carolinensis.

Admiral butterfly.

Adoption of the young of other animals by female monkeys.

Advancement in the organic scale, Von Baer’s definition of.

Aeby, on the difference between the skulls of man and the quadrumana.

Aesthetic faculty, not highly developed in savages.

Affection, maternal; manifestation of, by animals; parental and filial, partly the result of natural selection; mutual, of birds; shewn by birds in confinement, for certain persons.

Africa, probably the birthplace of man; South, crossed population of; South, retention of colour by the Dutch in; South, proportion of the sexes in the butterflies of; tattooing practised in; Northern, coiffure of natives of.

Agassiz, L., on conscience in dogs; on the coincidence of the races of man with zoological provinces; on the number of species of man; on the courtship of the land-snails; on the brightness of the colours of male fishes during the breeding season; on the frontal protuberance of the males of Geophagus and Cichla; male fishes hatching ova in their mouths; sexual differences in colour of chromids; on the slight sexual differences of the South Americans; on the tattooing of the Amazonian Indians.

Age, in relation to the transmission of characters in birds; variation in accordance with, in birds.

Agelaeus phoeniceus.

Ageronia feronia, noise produced by.

Agrion, dimorphism in.

Agrion Ramburii, sexes of.

Agrionidae, difference in the sexes of.

Agrotis exclamationis.

Ague, tertian, dog suffering from.

Ainos, hairiness of the.

Aitchison, Mr., on sheep.

Aithurus polytmus, young of.

Albino birds.

Alca torda, young of.

Alces palmata.

Alder and Hancock, MM., on the nudi-branch mollusca.

Allen, J.A., vigour of birds earliest hatched; effect of difference of temperature, light, etc., on birds; colours of birds; on the relative size of the sexes of Callorhinus ursinus; on the name of Otaria jubata; on the pairing of seals; on sexual differences in the colour of bats.

Allen, S., on the habits of Hoplopterus; on the plumes of herons; on the vernal moult of Herodius bubulcus.

Alligator, courtship of the male; roaring of the male.

Amadavat, pugnacity of male.

Amadina Lathami, display of plumage by the male.

Amadina castanotis, display of plumage by the male.

Amazons, butterflies of the; fishes of the.

America, variation in the skulls of aborigines of; wide range of aborigines of; lice of the natives of; general beardlessness of the natives of.

America, North, butterflies of; Indians of, women a cause of strife among the; Indians of, their notions of female beauty.

America, South, character of the natives of; population of parts of; piles of stones in; extinction of the fossil horse of; desert-birds of; slight sexual difference of the aborigines of; prevalence of infanticide in.

American languages, often highly artificial.

Americans, wide geographical range of; native, variability of; and negroes, difference of; aversion of, to hair on the face.

Ammophila, on the jaws of.

Ammotragus tragelaphus, hairy forelegs of.

Amphibia, affinity of, to the ganoid fishes; vocal organs of the.

Amphibians, breeding whilst immature.

Amphioxus.

Amphipoda, males sexually mature while young.

Amunoph III., negro character of, features of.

Anal appendages of insects.

Analogous variation in the plumage of birds.

Anas.

Anas acuta, male plumage of.

Anas boschas, male plumage of.

Anas histrionica.

Anas punctata.

Anastomus oscitans, sexes and young of; white nuptial plumage of.

Anatidae, voices of.

Anax junius, differences in the sexes of.

Andaman islanders, susceptible to change of climate.

Anderson, Dr., on the tail of Macacus brunneus; the Bufo sikimmensis; sounds of Echis carinata.

Andreana fulva.

Anglo-Saxons, estimation of the beard among the.

Animals, domesticated, more fertile than wild; cruelty of savages to; characters common to man and; domestic, change of breeds of.

Annelida, colours of.

Anobium tessellatum, sounds produced by.

Anolis cristatellus, male, crest of; pugnacity of the male; throat-pouch of.

Anser canadensis.

Anset cygnoides; knob at the base of the beak of.

Anser hyperboreus, whiteness of.

Antelope, prong-horned, horns of.

Antelopes, generally polygamous; horns of; canine teeth of some male; use of horns of; dorsal crests in; dewlaps of; winter change of two species of; peculiar markings of.

Antennae, furnished with cushions in the male of Penthe.

Anthidium manicatum, large male of.

Anthocharis cardamines; sexual difference of colour in.

Anthocharis genutia.

Anthocharis sara.

Anthophora acervorum, large male of.

Anthophora retusa, difference of the sexes in.

Anthropidae.

Anthus, moulting of.

Antics of birds.

Antigua, Dr. Nicholson’s observations on yellow fever in.

Antilocapra americana, horns of.

Antilope bezoartica, horned females of; sexual difference in the colour of.

Antilope Dorcas and euchore.

Antilope euchore, horns of.

Antilope montana, rudimentary canines in the young male of.

Antilope niger, sing-sing, caama, and gorgon, sexual differences in the colours of.

Antilope oreas, horns of.

Antilope saiga, polygamous habits of.

Antilope strepsiceros, horns of.

Antilope subgutturosa, absence of suborbital pits in.

Antipathy, shewn by birds in confinement, to certain persons.

Ants, large size of the cerebral ganglia in; soldier, large jaws of; playing together; memory in; intercommunication of, by means of the antennae; habits of; difference of the sexes in; recognition of each other by, after separation.

Ants White, habits of.

Anura.

Apatania muliebris, male unknown.

Apathus, difference of the sexes in.

Apatura Iris.

Apes, difference of the young, from the adult; semi-erect attitude of some; mastoid processes of; influences of the jaw-muscles on the physiognomy of; female, destitute of large canines; building platforms; imitative faculties of; anthropomorphous; probable speedy extermination of the; Gratiolet on the evolution of; canine teeth of male; females of some, less hairy beneath than the