Several authors have used the strongest expressions in describing these resplendent colours, which they examine with those of probably the most brilliant birds. With mammals we do not at current possess any evidence that the males take pains to display their charms before the feminine; and the frilly manner by which this is carried out by male birds and different animals, is the strongest argument in favour of the idea that the females admire, or are excited by, the ornaments and colours displayed earlier than them. This view is strengthened by the differences in colour between the sexes occurring almost exclusively, as may be collected from the earlier particulars, in those teams and subgroups of mammals, which current different and strongly-marked secondary sexual characters; these being likewise as a result of sexual selection. Deer rarely current any sexual differences in colour. Virginian deer is at all affected by emasculation. Lastly, as I am informed by Mr. Blyth, the mature male of the beautifully colored and noticed axis deer is significantly darker than the female; and this hue the castrated male by no means acquires. Lastly, within the baboon household, the adult male of Cynocephalus hamadryas differs from the female not solely by his immense mane, but barely in the color of the hair and of the bare callosities.
In the Cape eland additionally, the male is barely darker than the feminine. With most or the entire extremely-ornamented species of Tragelaphus the males are darker than the hornless females, and their crests of hair are more absolutely developed. With Pithecia leucocephala the young likewise resemble the females, that are brownish-black above and mild rusty-pink beneath, the grownup males being black. Fig. 69.) Within the adult females and within the young of both sexes these protuberances are scarcely perceptible; and the bare parts are much much less vivid coloured, the face being nearly black, tinged with blue. In the Cercopithecus cynosurus and griseoviridis one part of the physique, which is confined to the male intercourse, is of probably the most sensible blue or inexperienced, and contrasts strikingly with the bare skin on the hinder part of the body, which is vivid pink. I might right here point out that Judge Caton has in his park three races of the Virginian deer, which differ slightly in color, but the variations are nearly completely confined to the blue winter or breeding coat; in order that this case may be compared with those given in a earlier chapter of intently-allied or consultant species of birds, which differ from each other only of their breeding plumage.
In an earlier chapter we have seen that the psychological powers of the upper animals do not differ in type, though enormously in diploma, from the corresponding powers of man, especially of the lower and barbarous races; and it would appear that even their style for the gorgeous will not be extensively totally different from that of the Quadrumana. I have now given all of the cases known to me of a difference in color between the sexes of mammals. In all of the instances hitherto given the male is more strongly or brighter coloured than the female, and differs from the younger of both sexes. But as with some few birds it’s the female which is brighter coloured than the male, so with the Rhesus monkey (Macacus rhesus) the feminine has a large surface of naked pores and skin round the tail, of an excellent carmine pink, which, as I used to be assured by the keepers within the Zoological Gardens, periodically turns into even but extra vivid, and her face also is pale red.
Within the Antilope niger the male is black, the feminine, as nicely as the younger of each sexes, being brown; in A. sing-sing the male is much brighter colored than the hornless feminine, and his chest and stomach are blacker; within the male A. caama, the marks and lines which occur on various components of the body are black, instead of brown as in the feminine; within the brindled gnu (A. A difference of this sort is basic in the Strepsicerene antelopes; thus the male nilghau (Portax picta) is bluish-gray and far darker than the feminine, with the sq. white patch on the throat, the white marks on the fetlocks, and the black spots on the ears all rather more distinct. In a couple of exceptional instances the feminine in both courses is extra extremely ornamented than the male. In each courses, when the male differs from the female, the young of each sexes nearly always resemble one another, and in a big majority of instances resemble the adult feminine. The emasculated bull reverts to the color of the feminine. Quadrupeds manifestly take discover of color. It’s on the entire probable that the strongly-marked colours and other ornamental characters of male quadrupeds are helpful to them of their rivalry with other males, and have consequently been acquired through sexual selection.