Chap. XVIII. ORNAMENTAL COLOURS. 295 



sexually limited in their transmission. Nevertheless 

 it can hardly be admitted that the diversified, vivid, 

 and contrasted colours of certain quadrupeds, for in- 

 stance of the above-mentioned monkeys and antelopes, 

 can thus be accounted for. We should bear in mind 

 that these colours do not appear in the male at birth, 

 as in the case of most ordinary variations, but only at 

 or near maturity ; and that unlike ordinary variations, 

 if the male be emasculated, they never appear or sub- 

 sequently disappear. It is on the whole a much more 

 probable conclusion that the strongly-marked colours 

 and other ornamental characters of male quadrupeds 

 are beneficial to them in their rivalry with other males, 

 and have consequently been acquired through sexual 

 selection. The probability of this view is strengthened 

 by the differences in colour between the sexes occur- 

 ring almost exclusively, as may be observed by going 

 through the previous details, in those groups and sub- 

 groups of mammals, which present other and distinct 

 secondary sexual characters ; these being likewise due 

 to the action of sexual selection. 



Quadrupeds manifestly take notice of colour. Sir 

 S. Baker repeatedly observed that the African elephant 

 and rhinoceros attacked with special fury white or grey 

 horses. I have elsewhere shewn ^^ that half-wild horses 

 apparently prefer pairing with those of the same colour, 

 and that herds of fallow-deer of a different colour, though 

 living together, have long kept distinct. It is a more 

 significant fact that a female zebra. would not admit the 

 addresses of a male ass until he was painted so as to 

 resemble a zebra, and then, as John Hunter remarks, 

 " she received him very readily. In this curious fact. 



32 ' The Variation of Animals and Plants under Domestica^^i^MGcSV^ C 

 vol. ii. p. 102, 103. AO o^^^ ^O 



uuIlibrar 



