Chap. XVIII. 
SPOTS AND STRIPES. 
305 
the lion and puma from the open nature of the localities 
which they commonly haunt, to have lost their stripes, 
and to have been thus rendered less conspicuous to their 
prey ; and if the successive variations, by which this 
end was gained, occurred rather late in life, the young 
would have retained their stripes, as we know to be the 
case. In regard to deer, pigs, and tapirs, Fritz Muller 
lias suggested to me that these animals by the removal 
through natural selection of their spots or stripes would 
have been less easily seen by their enemies ; and they 
would have especially required this protection, as soon 
as the carnivora increased in size and number during 
the Tertiary periods. This may be the true explana- 
tion, but it is rather strange that the young should 
not have been equally well protected, and still more 
strange that with some species the adults should have 
retained their spots, either partially or completely, 
during part of the year. We know, though we cannot 
explain the cause, that when the domestic ass varies and 
becomes reddish-brown, grey or black, the stripes on the 
shoulders and even on the spine frequently disappear. 
Very few horses, except dun-coloured kinds, exhibit 
stripes on any part of their bodies, yet we have good 
reason to believe that the aboriginal horse was striped 
on the legs and spine, and probably on the shoulders.^^ 
Hence the disappearance of the spots and stripes in our 
adult existing deer, pigs, and tapirs, may be due to a 
change in the general colour of their coats ; but whether 
this change was effected through sexual or natural se- 
lection, or was due to the direct action of the conditions 
of life, or some other unknown cause, it is impossible 
to decide. An observation made by Mr. Sclater well 
illustrates our ignorance of the laws which regulate the 
‘ The Variation of Animals and Plants under Domestication/ 
1868, vol. i. p. 61-61. 
VOL. II. 
X 
