The Descent of Man

esemblance. 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
the roe is the Capreolus sibiricus subecaudatus