But horns, as horns, apart from their “accidents” of curvature and ornament, must certainly be regarded as the product of Sexual selection, for having once started into being those individuals had the best chance of leaving descendants which were best armed. The possession of horns was not necessary to the maintenance of the species; but such armature was essential among the males in securing possession of the females. Other things being equal, the male with the biggest horns wins the prize. Since these are also used as weapons of offence, or rather of defence, in warding off the attacks of beasts of prey, it might be contended that they are as much the product of Natural selection as of Sexual selection.
It soon becomes apparent that this interpretation must fail. In the first place, if it were true, the females should be similarly armed. In the second, in the presence of many of their enemies they are useless. The Cape hunting-dog, for example, is more than a match for any antelope. This ferocious animal kills his victim by running it down, persistently tearing at its flanks, until at last the entrails protrude and the horrid chase is ended. Furthermore, the horns are a comparatively late acquirement of the species, as is shown in the case of the Deer; for the earliest known fossil species were hornless. That the females among the Oxen and many of the Antelopes possess horns is an interesting fact, but it can only be regarded as another instance of a character first acquired by the male and later, in successive generations, transferred to the female. And it is to be noticed that this transference is never found save in the cases where the character in question has attained its maximum in the male. The transference of weapons to the female is the more remarkable because there is no evidence that they play any part in the struggle for existence, either in securing mates or in warding off the attacks of enemies. Moreover, these weapons in the female may exceed those of the male, in length, though they are never so massive. They are to be regarded solely in the light of ornaments. There are few more striking instances indeed where the purely ornamental and the strictly utilitarian are so closely associated.
Plate 4.
By the courtesy of Rowland, Ward, Ltd.
WEAPONS OF OFFENCE.
Horns of various types furnish the most conspicuous of the “Secondary Sexual Characters” of the ruminants. In the Deer only are these branched. In the “hollow-horned” ruminants they are either lance-like or more or less spirally curved, or they may form more or less open loops.
1. Black-tailed Deer. 2. Hangul or Kashmir Barasingha Deer. 3. Greater Kudu. 4. Black-buck. 5. Saiga Antelope, remarkable also for its curiously swollen nose. 6. Marco-Polo’s Sheep.
[Face page 52.
Attention may now profitably be turned to the behaviour of these interesting tribes when under the alluring influences of love.