The terrestrial Carnivora and Insectivora rarely exhibit sexual differences of any kind, and their colours are almost always exactly the same in both sexes. The ocelot (_Felis pardalis_), however, offers an exception, for the colours of the female, compared with those of the male, are “moins apparentes, le fauve étant plus terne, le blanc moins pur, les raies ayant moins de largeur et les taches moins de diamètre.”[353] The sexes of the allied _Felis mitis_ also differ, but even in a less degree, the general hues of the female being rather paler than in the male, with the spots less black. The marine Carnivora or Seals, on the other hand, sometimes differ considerably in colour, and they present, as we have already seen, other remarkable sexual differences. Thus the male of the _Otaria nigrescens_ of the southern hemisphere is of a rich brown shade above; whilst the female, who acquires her adult tints earlier in life than the male, is dark-grey above, the young of both sexes being of a very deep chocolate colour. The male of the northern _Phoca groenlandica_ is tawny grey, with a curious saddle-shaped dark mark on the back; the female is much smaller, and has a very different appearance, being “dull white or yellowish straw-colour, with a tawny hue on the back;” the young at first are pure white, and can “hardly be distinguished among the icy hummocks and snow, their colour thus acting as a protection.”[354] With Ruminants sexual differences of colour occur more commonly than in any other order. A difference of this kind is general with the Strepsicerene antelopes; thus the male nilghau (_Portax picta_) is bluish-grey and much darker than the female, with the square white patch on the throat, the white marks on the fetlocks, and the black spots on the ears, all much more distinct. We have seen that in this species the crests and tufts of hair are likewise more developed in the male than in the hornless female. The male, as I am informed by Mr. Blyth, without shedding his hair, periodically becomes darker during the breeding-season. Young males cannot be distinguished from young females until above twelve months old; and if the male is emasculated before this period, he never, according to the same authority, changes colour. The importance of this latter fact, as distinctive of sexual colouring, becomes obvious, when we hear[355] that neither the red summer-coat nor the blue winter-coat of the Virginian deer is at all affected by emasculation. With most or all of the highly-ornamented species of Tragelaphus the males are darker than the hornless females, and their crests of hair are more fully developed. In the male of that magnificent antelope, the _Derbyan Eland_, the body is redder, the whole neck much blacker, and the white band which separates these colours, broader, than in the female. In the Cape Eland also, the male is slightly darker than the female.[356]