of hair or feathers, or other such appendages. In a few exceptional
cases the female in both classes is more highly ornamented than the
male. With many mammals, and at least in the case of one bird, the male
is more odoriferous than the female. In both classes the voice of the
male is more powerful than that of the female. Considering this
parallelism, there can be little doubt that the same cause, whatever it
may be, has acted on mammals and birds; and the result, as far as
ornamental characters are concerned, may be attributed, as it appears
to me, to the long-continued preference of the individuals of one sex
for certain individuals of the opposite sex, combined with their
success in leaving a larger number of offspring to inherit their
superior attractions.
EQUAL TRANSMISSION OF ORNAMENTAL CHARACTERS TO BOTH SEXES.
With many birds, ornaments, which analogy leads us to believe were
primarily acquired by the males, have been transmitted equally, or
almost equally, to both sexes; and we may now enquire how far this view
applies to mammals. With a considerable number of species, especially
of the smaller kinds, both sexes have been coloured, independently of
sexual selection, for the sake of protection; but not, as far as I can
judge, in so many cases, nor in so striking a manner, as in most of the
lower classes. Audubon remarks that he often mistook the musk-rat (35.
Fiber zibethicus, Audubon and Bachman, The Quadrupeds of North
America, 1846, p. 109.), whilst sitting on the banks of a muddy
stream, for a clod of earth, so complete was the resemblance. The hare
on her form is a familiar instance of concealment through colour; yet
this principle partly fails in a closely-allied species, the rabbit,
for when running to its burrow, it is made conspicuous to the
sportsman, and no doubt to all beasts of prey, by its upturned white
tail. No one doubts that the quadrupeds inhabiting snow-clad regions
have been rendered white to protect them from their enemies, or to
favour their stealing on their prey. In regions where snow never lies
for long, a white coat would be injurious; consequently, species of
this colour are extremely rare in the hotter parts of the world. It
deserves notice that many quadrupeds inhabiting moderately cold
regions, although they do not assume a white winter dress, become paler
during this season; and this apparently is the direct result of the
conditions to which they have long been exposed. Pallas (36. Novae
species Quadrupedum e Glirium ordine, 1778, p. 7. What I have called
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