SEXUAL DIMORPHISM
_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._
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 naïve enemies. True to her
rôle 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.