^88 
SEXUAL SELECTION: MAMMALS. 
Papt II. 
and the black spots on the ears, all much more dis- 
tinct. 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-sea- 
son. Young males cannot be distinguished from young 
females until above twelve months old; and if the 
male is emasculated before this period, he never, accord- 
ing to the same authority, changes colour. The import- 
ance of this latter fact, as distinctive of sexual colouring, 
becomes obvious, when we hear^^ 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.^^ 
In the Indian Black-buck [A, lezoartica), which belongs 
to another tribe of antelopes, the male is very dark, almost 
black ; whilst the hornless female is fawn-coloured. We 
have in this species, as Mr. Blyth informs me, an exactly 
parallel series of facts, as with the Poriax jpicta, namely in 
the male periodically changing colour during the breed- 
Judge Caton, in ‘ Trans. Ottawa Acad, of Nat. Sciences,’ 1868, 
p. 4. 
Dr. Gray, ‘ Cat. of Mamm. in Brit. Mus.’ part iii. 1852, p. 134-142 ; 
also Dr. Gray, ‘ Gleanings from the Menagerie of Knowsley,’ in which 
there is a splendid drawing of the Oreas derbianus : see the text on 
Tragelaphus. For the Cape Eland {Oreas canna), see Andrew Smith, 
‘ Zoology of S. Africa/ pi. 41 and 42. There are also many of these 
antelopes in the Zoological Society’s Gardens. 
