298 
SEXUAL selection: mammals. 
Paet II. 
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 
may be extended to mammals. With a considerable 
number of species, especially the smaller kinds, both 
sexes have been coloured, independently of sexual selec- 
tion, for the sake of protection ; but not, as far as I can 
judge, in so many cases, nor in nearly so striking a 
manner as in most of the lower classes. Audubon re- 
marks that he often mistook the musk-rat, 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, 
namely the rabbit, for as this animal runs to its burrow, 
it is made conspicuous to the sportsman and no doubt 
to all beasts of prey, by its upturned pure-white tail. 
No one has ever doubted that the quadrupeds which 
inhabit 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 long on the ground a white coat would be inju- 
rious ; consequently species thus coloured are extremely 
rare in the hotter parts of the world. It deserves notice 
that many quadrupeds, inhabiting moderately cold re- 
gions, 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 states that in Sibe- 
ria a change of this nature occurs with the wolf, two 
species of Mustela, the domestic horse, the JEquus he- 
Fiber zibefMciis, Audubon and Bachman, ‘ The Quadrupeds of 
N. America,’ 1846, p. 109. 
26 ‘ Novai species QuadrujDedum e Glirium ordine,’ 1778, p. 7. WLat 
I have called the roe is the Caxjreolus Sibiricus subecaudatus of Pallas. 
ij 
