The Courtship of Animals

by W. P. Pycraft

Plate 3.

From drawings by I. Thornton.

THE BAROMETER OF MALENESS—AMONG THE APES.

All the Man-like Apes possess great canine teeth and powerful voices. In the Orangutan the Compass of the voice is enormously heightened by means of a huge wind-bag which encircles the neck. The wind-bag is seen in fig. 1, which also shows the great folds of skin developed by adult males on each side of the face. In other species, as in the Tamarin Marmoset (Midas imperator) (fig. 2), and the Satan monkey (Pithecia satanus) (fig. 3), “ornaments” in the shape of beards and moustaches are developed, while in the Mandrill (fig. 4) the face is vividly coloured.

[Face page 44.

In the development of brilliantly-coloured areas of bare skin the monkeys stand alone among the Mammalia. The hues displayed are remarkable for their brilliancy, and this varies in intensity, waxing and waning with the varying moods of their possessors, and attaining their maximum during periods of sexual excitement. Blue, green, red, and violet are the dominant colours, and these are confined to the face, buttocks, and genital organs. The same hues are commonly present in both sexes, though in the female they are less brilliant. Normally the male appears to be unconscious of the conspicuous patches of colour, but when under the irrepressible stimulus of sexual excitement he seems to endeavour to make the utmost possible capital out of such adornments, more especially presenting his buttocks to his mate in an apparent endeavour to stimulate her desire. In some species, as with the Baboons for example, the naked area of this hinder part of the body is a much more conspicuous feature in the female than in the male, becoming enormously swollen and carunculated, and from its vivid red colour presents a positively revolting appearance, according to our standard of what is beautiful. The most vividly coloured species of all is the Mandrill, which, in this matter exceeds all other living Mammals. The face, in the male, is produced forward to give the head a dog-like shape, while the whole of the upper surface of the muzzle has been transformed into a swollen, deeply fluted mass by the excessive inflation of the underlying bone. The bare skin covering this is of a brilliant cobalt blue, with lines of violet in the furrows, while the nose is of a bright scarlet. The naked skin of the buttocks, and the genital organs, are suffused with brilliant tints of scarlet and blue. In spite of the purity and brilliance of the coloration the effect is to make the creature really hideous.

Of the display Cuvier writes: “La partie postérieure du corps n’est ni moins extraordinaire ni moins révoltante. Sous une courte queue sans cesse relevée est un anus entouré d’un gros bourrelet d’écarlate; de larges fesses nues, que l’animal semble montrer sans cesse avec autant de lascivité que d’impudence, sont colorées d’un rose vif nuancé sur les côtés de lilas et de bleu. Les parties genitales enfin sont d’un rouge de feu d’autant plus tranché qu’elles sont absolument nues, et qu’elles viennent a la suite d’un abdomen revêtu de poils blancs.”

While we cannot suppose these animals to possess any standard of beauty or ugliness, it must not be forgotten that they are more or less conscious, not only of the existence of these brightly-coloured areas, but of the effect they produce, as Darwin showed long since in the cases of a captive Mandrill, and some other smaller species of Monkeys, among them a Rhesus Monkey. These, when shown a looking-glass, at once presented their hinder ends to what they supposed to be the new arrival. A similar mark of friendliness was shown towards their keeper, and visitors introduced by him. Periodically, under the sexual stimulus, this desire becomes intensified and becomes an invitation to mating.

In this connection it is interesting to note that in some of the Macaque Monkeys we have signs of a reversal of the usual sequence of coloration. For in the Pigtailed Macaque the young of both sexes are more brilliantly coloured than the adults, in regard to the bare skin areas, while in the Hairy-eared Macaque (M. lasiotis) and the Rhesus Monkey (M. rhesus) the face of the female is brighter than that of the male. This surely means that this coloration is in process of suppression, for according to the rule the male is the first to develop new characters, then the female, and finally they are transmitted to the young. The extra brightness in the young, then, is to be regarded not as an incipient, but as an ancestral character in process of elimination.