Chapter 5 SEXUAL DIMORPHISM No.5

II. Vertebrates:-Unnoticeable in fish, saurians, reptiles.-The Bird World.-Dimorphism favourable to males: the oriole, pheasants, the ruff.-Peacocks and turkey-cocks.-Birds of paradise.-Moderate dimorphism of mammifers.-Effects of castration on dimorphism.

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II. Vertebrates.-Sexual differences are generally unnoticeable in fish, reptiles and saurians. They are accentuated when we come to superior vertebrates, to birds and mammals, but without ever attaining the extreme difference which characterizes a great number of arthropodes. In birds the disparity may be of colouring, size, or length, form and curliness of the feathers; among mammals, of shape, hair, beard or horns. Sometimes the female bird is finer and stronger; thus stronger and of more powerful wing-spread in the case of the secretary, the buzzard, the falcon, the ash-coloured vulture and many birds of prey; more beautiful as in the Indian tumices.[1] One of them, the gray phalarope, solves woman's dream in favour of the female, leaving her the brilliant colours; the male contents himself with more sober clothing and, not being able to lay, assumes at least the further maternal cares: sitting on the eggs.

In general, nature is, in the bird world, favourable to the male. He is a prince whose wife appears morganatic. Often smaller, as the female canepetiere (a sort of bustard), while the female garden warbler is nearly always clothed as Cinderella. The birds which women have massacred in millions in order to deck themselves as parrots and jays, are male birds for the most part; their sisters bear more modest clothing, and one would say that this humility, become favourable to their species, had been developed by nature in provision of human stupidity and badheartedness. The gold-yellow oriole with black wings and tail, has for mate a brown sparrow with grey and greenish touches. The silver pheasant (a false pheasant) has a black tuft standing up from his silver-white nape, his neck and back are of the same metal; his dark belly has a blue shimmer, his beak is blue, his cheeks red, and his feet, red. The smaller female covers her belly sadly in a whitish chemise, her back is russet. In the true pheasant the dimorphism is still more marked. The large, proud male (we are dealing with the common pheasant) who has no objection to being admired, is deep green on nape and neck, copper-red with violet shimmer on back, flanks, belly and breast; his tail russet with black bands, a reddish brown tuft spreads from his head, and the eye-circle is vivid red. The much smaller female has an earthy plumage speckled with black. The fair Golden Pheasant is really all golden over green. His yellow tail and wings and his saffron red belly complete this marvellous masculine splendour. The female must content herself with burnt sienna back-covering which comes down onto her ochre-coloured belly.

A little head projecting from an enormous neck-circle of white out-puffing feathers, middle sized body, and long legs. It is the combatant (ruff-bird). One must add a tapering beak, ornamented at the base by a sort of red grape. One can't say what colour the male is, he is of all colours. One leaves him white, and finds him red; he was black, and is violet; later he will be speckled or banded in most varied hues. His ruff is an ornament and a defence; he loses both it and his red grape with the passing of his fighting and loving season. This instability of feathering accords curiously with the instability of his character; no animal is more irritable or cantankerous. One can not keep him captive save solitary and in obscurity. The female, somewhat less turbulent never changes her vestment, an invariable gray, with a small amount of brown on the back.

Peacocks and turkey-cocks alone can spread wheel-wise their fan-tails, as also the cock bustard; they alone are provided with great wattles. The menure hen lifts, as the cock, a lyre of feathers, but it is a tarnished and mediocre imitation of her master's, which glistens in all shades rising and curving with such paradoxical grace.

The dimorphism of birds of paradise is even more marked than in the preceding cases. Nape citron-yellow, throat green, forehead black, back in burnt chestnut, the cock's tail has two long plumes, his flanks two fine tapering feathers of yellow-orange marked in red, which he can spread branching or draw in at will; the dim female is without ornament. The sifilet, a bird related to the birds of paradise has, fixed between eye and ear a pair of fine plumes twice the length of his body, which float as he walks like white blue-shimmering streamers. It is a lover's paraphernalia, which the female in consequence does without, while the male loses his after mating.

The dissemblance of barnyard cock and hen are well enough known to give everyone a clear idea of dimorphism in birds and to show difference of characters parallel with difference of form.

The dimorphism of mammals is even less often favourable to the female than is that of birds. One can cite but the sole example of the American tapir where the male is smaller than the female.[2] The contrary is nearly always the case. Sometimes the two sexes have an identical appearance: cougars, cats, panthers, servals. If there is a rule, it is difficult to formulate, for side by side with these felines without sexual dimorphism, the sex of lions and tigers clearly determines their forms.

Among mammifers there are bizarre resemblances and baroque differences. The he and she mole, at first sight, appear the same even to their exterior sexual organs, the female's clitoris is, like the male's penis, perforated to let the ureter pass through it. But here, as we shall see later, the morphologic resemblance by no means indicates similarity of characters; the female mole is excessively female. There is baroque difference of sexes in the capped seal of Greenland and Terra Nova. The male can puff out his head-skin into an enormous helmet. To what purpose? Possibly to scare na?ve enemies. True to her r?le of protégé the female can not throw this bluff, which is used by Chinese warriors, by certain insects like the mantis and by the cobra among serpents.

She-brown bears and she-kangaroos are smaller than males. In all the deer tribes save reindeer the male alone is horned, and this is the by no means ridiculous origin of a very old joke, for the does are lascivious and are pleased to receive the attentions of a number of males. The difference of bull and cow is distinct enough, that of stallion and mare less so, diminishing still further between dog and bitch, and being almost null among cats. In all cases where the dimorphism is slight, and is the direct consequence of the possession of sexual organs, castration inclines the male toward the female type.[3] This is as apparent in cattle as in eunuchs or gelded horses. One may see in this yet another proof of the primitivity of the female, since the abstraction of testicles suffices to give the male that softness of form and character which typifies females. Masculinity is an augmentation, an aggravation of the normal type represented by femininity; it is a progress, and in this sense it is a development. But this reasoning, good for mammals, would be detestable among insects, where the accentuation of type is nearly always furnished by the female. There are no general laws in nature, unless they be those which regulate all matter. With the birth of life, the unique tendency diverges at once upon multiple lines. Perhaps we must throw this point of divergence still further back, for a metal like radium seems to differ from other metals as much as an hymenopter from a gasteropod.

[1] Bird, rather like quail.

[2] Translator's note. O sinistre continent.

[3] Castration of females seems, at least, among humans, to bring them nearer the male type. Effects of castration vary, necessarily, according to the age of the subject.

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