The Descent of Man

In all the wild species of goats and sheep the
horns are larger in the male than in the female,
and are sometimes quite absent in the latter.
(13. Gray, 'Catalogue of Mammalia, the British
Museum,' part iii. 1852, p. 160.) In several domestic
breeds of these two animals, the males
alone are furnished with horns; and in some
breeds, for instance, in the sheep of North Wales,
though both sexes are properly horned, the
ewes are very liable to be hornless. I have been
informed by a trustworthy witness, who purposely
inspected a flock of these same sheep
during the lambing season, that the horns at
birth are generally more fully developed in the
male than in the female. Mr. J. Peel crossed his
Lonk sheep, both sexes of which always bear
horns, with hornless Leicesters and hornless
Shropshire Downs; and the result was that the
male offspring had their horns considerably
reduced, whilst the females were wholly destitute
of them. These several facts indicate that,
with sheep, the horns are a much less firmly