284 SEXUAL SELECTION: MAMMALS. [Part II. 



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 remarks that he often mistook 

 the musk-rat, 35 while sitting on the banks of a muddy 

 stream, for a clod of earth, so complete was the resem- 

 blance. The hare on her form is a familiar instance of 

 concealment through color ; 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 up- 

 turned pure-white tail. ]STo one has ever doubted that the 

 quadrupeds which inhabit snow-clad regions have been 

 rendered white to protect them from their enemies, or to 

 favor 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 colored 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 ex- 

 posed. Pallas 36 states that in Siberia a change of this na- 

 ture occurs with the wolf, two species of Mustela, the do- 

 mestic horse, the Equus hemionus, the domestic cow, two 

 species of antelopes, the musk-deer, the roe, the elk, and 

 reindeer. The roe, for instance, has a red summer and a 

 grayish- white winter coat ; and the latter may perhaps 

 serve as a protection to the animal while wandering 

 through the leafless thickets, sprinkled with snow and 

 hoar-frost. If the above-named animals were gradually 

 to extend their range into regions perpetually covered 



85 Fiber zibethicus, Audubon and Bachman, ' The Quadrupeds of North 

 America,' 1846, p. 109. 



36 'jsovge species Quadrupedum e Glirium ordine,' l^^, p. 7. What 

 1 have called the roe is the Capreolus Sibiricus subecaudatus of Pallas. 



