54° The Descejit of Man. Part 11. 



and he is certain that all, or nearly all these animals, were males. 

 On the other hand, with wolves, foxes, and apparently American 

 squirrels, both sexes are occasionally born black. Hence it is 

 quite possible that with some mammals a difference in colour 

 between the sexes, especially when this is congenital, may simply 

 be the result, without the aid of selection, of the occurrence of 

 one or more variations, which from the first were sexually limited 

 in their transmission. Nevertheless it is improbable that the 

 diversified, vivid, and contrasted colours of certain quadrupeds, 

 for instance, of the above monkeys and antelopes can thus be 

 accounted for. We should bear in mind that these colours do 

 not appear in the male at birth, but only at or near maturity ; 

 and that unlike ordinary variations, they are lost if the male be 

 emasculated. It is on the whole probable 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. This view is strengthened by the differences in 

 colour between the sexes occurring almost exclusively, as may 

 be collected from the previous details, in those groups and sub- 

 groups of mammals, which present other and strongly-marked 

 secondary sexual characters ; these being likewise due to sexual 

 selection. 



Quadrupeds manifestly take notice of colour. Sir S. Baker 

 repeatedly observed that the African elephant and rhinoceros 

 attacked white or grey horses with special fury. I have else- 

 where shewn 32 that half- wild horses apparently prefer to pair 

 with those of the same colour, and that herds of fallow-deer of 

 different colours, 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, we have 

 " instinct excited by mere colour, which had so strong an effect 

 " as to get the better of everything else. But the male did not 

 " require this, the female being an animal somewhat similar to 

 " himself, was sufficient to rouse him." 33 



In an earlier chapter we have seen that the mental powers of 

 the higher animals do not differ in kind, though greatly in 

 degree, from the corresponding powers of man, especially of the 

 lower and barbarous races ; and it would appear that even their 

 taste for the beautiful is not widely different from that of the 



32 ' The Variation of Animals and 33 ' Essays and Observations by 



Plants under Domestication,' 1868, J. Hunter,' edited by Owen, 1861, 

 vol. ii. pp. 102, 103. vol. i. p. 194. 



