MAMMALS— ORNAMENTAL COLORS. 535 



the same sex, without any good being gained, and therefore with- 

 out the aid of selection. We have instances of this with our 

 domesticated animals, as in the males of certain cats being rusty- 

 red, whilst the females are tortoise-shell colored. Analogous 

 cases occur in nature: Mr. Bartlett has seen many black varieties 

 of the jaguar, leopard, vulpine phalanger, and wombat; and fie 

 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 bom black. Hence it is 

 quite possible that with some mammals a difference In color 

 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 colors of certain quadrupeds, 

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

 accounted for. We should boar in mind that these colors 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 emas- 

 culated. It is on the whole probable that the strongly-marked 

 colors 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 color between the sexes 

 occurring almost exclusively, as may be collected from the pre- 

 vious 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 color. Sir S. Baker re- 

 peatedly observed that the African elephant and rhinoceros at- 

 tacked white or gray horses with special fury. I have elsewhere 

 shown'^' that half-wild horses apparently prefer to pair with those 

 of the same color, and that herds of fallow-deer of different col- 

 ors, 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 color, 

 "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."=" 



^ 'The Variation of Animals and Plants under Domestication,' 1868, 

 vol. il. pp. 102, 103. 



^ 'Essays and Observations by J. Hunter,' edited by Owen, 1861, 

 vol. 1. p. 194. 



