Male quadrupeds which are furnished with tusks use them in various ways, as in the case of horns. The boar strikes laterally and upwards; the musk-deer with serious effect downwards.[311] The walrus, though having so short a neck and so unwieldy a body, “can strike either upwards, or downwards, or sideways, with equal dexterity.”[312] The Indian elephant fights, as I was informed by the late Dr. Falconer, in a different manner according to the position and curvature of his tusks. When they are directed forwards and upwards he is able to fling a tiger to a great distance—it is said to even thirty feet; when they are short and turned downwards he endeavours suddenly to pin the tiger to the ground, and in consequence is dangerous to the rider, who is liable to be jerked off the hoodah.[313] Very few male quadrupeds possess weapons of two distinct kinds specially adapted for fighting with rival males. The male muntjac-deer (_Cervulus_), however, offers an exception, as he is provided with horns and exserted canine teeth. But one form of weapon, has often been replaced in the course of ages by another form, as we may infer from what follows. With ruminants the development of horns generally stands in an inverse relation with that of even moderately well-developed canine teeth. Thus camels, guanacoes, chevrotains and musk-deer, are hornless, and they have efficient canines; these teeth being “always of smaller size in the females than in the males.” The Camelidæ have in their upper jaws, in addition to their true canines, a pair of canine-shaped incisors.[314] Male deer and antelopes, on the other hand, possess horns, and they rarely have canine teeth; and these when present are always of small size, so that it is doubtful whether they are of any service in their battles. With _Antilope montana_ they exist only as rudiments in the young male, disappearing as he grows old; and they are absent in the female at all ages; but the females of certain other antelopes and deer have been known occasionally to exhibit rudiments of these teeth.[315] Stallions have small canine teeth, which are either quite absent or rudimentary in the mare; but they do not appear to be used in fighting, for stallions bite with their incisors, and do not open their mouths widely like camels and guanacoes. Whenever the adult male possesses canines now in an inefficient state, whilst the female has either none or mere rudiments, we may conclude that the early male progenitor of the species was provided with efficient canines, which had been partially transferred to the females. The reduction of these teeth in the males seems to have followed from some change in their manner of fighting, often caused (but not in the case of the horse) by the development of new weapons.