294 
SEXUAL SELECTION: MAMMALS. 
Part II. 
the adult male and with the young of both sexes, as I 
saw in the Gardens, neither the naked skin at the 
posterior end of the body, nor the face, shew a trace 
of red. It appears, however, from some published 
accounts, that the male does occasionally, or during 
certain seasons, exhibit some traces of the red. Although 
he is thus less ornamented than the female, yet in the 
larger size of his body, larger canine teeth, more de- 
veloped whiskers, more prominent superciliary ridges, 
he follows the common rule of the male excelling the 
female. 
I have now given all the cases known to me of a dif- 
ference in colour between the sexes of mammals. The 
colours of the female either do not differ in a sufficient 
degree from those of the male, or are not of a suitable 
nature, to afford her protection, and therefore cannot be 
explained on this principle. In some, perhaps in many 
cases, the differences may be the result of variations 
confined to one sex and transmitted to the same sex, 
without any good having been thus gained, and there- 
fore without the aid of selection. We have instances 
of this kind with our domesticated animals, as in the 
males of certain cats being rusty-red, whilst the females 
are tortoise-shell coloured. Analogous cases occur 
under nature ; Mr. Bartlett has seen many black var- 
ieties of the jaguar, leopard, vulpine phalanger and 
wombat ; and he is certain that all, or nearly all, were 
males. On the other hand, both sexes of wolves, 
foxes, and apparently of American squirrels, are occa- 
sionally born black. Hence it is quite possible that 
with some mammals the blackness of the males, especi- 
ally when this colour is congenital, may simply be the 
result, without the aid of selection, of one or more 
variations having occurred, which from the first were 
