Pigeons offer a more interesting case; for throughout the whole great family
the two sexes do not often differ much; and the males and females of the
parent-form, the C. livia, are undistinguishable: yet we have seen that with
pouters the male has the characteristic quality of pouting more strongly
developed than the female; and in certain sub-varieties the males alone are
spotted or striated with black, or otherwise differ in colour. When male and
female English carrier-pigeons are exhibited in separate pens, the difference
in the development of the wattle over the beak and round the eyes is
conspicuous. So that here we have instances of the appearance of secondary
sexual characters in the domesticated races of a species in which such
differences are naturally quite absent.]

On the other hand, secondary sexual characters which belong to the species in
a state of nature are sometimes quite lost, or greatly diminished, under
domestication. We see this in the small size of the tusks in our improved
breeds of the pig, in comparison with those of the wild boar. There are sub-
breeds of fowls, in which the males have lost the fine-flowing tail-feathers
and hackles; and others in which there is no difference in colour between the
two sexes. In some cases the barred plumage, which in gallinaceous birds is
commonly the attribute of the hen, has been transferred to the cock, as in the
cuckoo sub-breeds. In other cases masculine characters have been partly
transferred to the female, as with the splendid plumage of the golden-spangled
Hamburgh hen, the enlarged comb of the Spanish hen, the pugnacious disposition
of the Game hen, and as in the well-developed spurs which occasionally appear
in the hens of various breeds. In Polish fowls both sexes are ornamented with
a topknot, that of the male being formed of hackle-like feathers, and this is
a new male character in the genus Gallus. On the whole, as far as I can judge,
new characters are more apt to appear in the males of our domesticated animals
than in the females (14/29. I have given in my 'Descent of Man' 2nd edition
page 223 sufficient evidence that male animals are usually more variable than