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 o'ained, occurred rather late in life, the voun^ 

 would have retained their stripes, as we know to be the 

 case. In regard to deer, ])igs, and tapirs, Fritz Miiller 

 has 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. 

 Yery 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 



*2 ' The Variation of Animals and Plants under Domestication,' 

 1868, vol. i. p. 61-G4. 



YOL. II. X 



