70 MARINE AND AQUATIC TRESPASSERS. 



fact that only the male possesses this tusk ; so that it 

 could not be used for the purpose of gaining food, or, 

 indeed, of preserving life in any direct manner. 



In the Walrus, however, both sexes possess the 

 tusks ; so that no such difficulty arises. One use to 

 which these enormous tusks are put, is to aid the 

 animal in dragging its huge body upon the shore. 

 Another use is, to tear up the algae which grow 

 upon the rocks below water-mark : for this Seal is 

 omnivorous, and, besides eating fish, Crustacea, and 

 other animal substances, feeds also upon the marine 

 vegetation. 



The tusks are larger in the males than in the 

 females, and are used on occasions either when they 

 fight with each other, or when they are engaged in 

 defence against other enemies. The worst of them is 

 the Polar bear, which, however, is often beaten off by 

 a powerful male Walrus, though the skin of the latter 

 shows many deep wounds caused by his enemy's claws. 



When they fight among themselves, it is almost 

 invariably in the breeding season. Each male has 

 quite a harem of females, over whom he watches with 

 the extremest jealousy, though he does not lose an 

 opportunity for decoying a member of a neighbouring 

 harem into his own premises. 



The very peculiar shape of the muzzle is caused by 

 the very large bony sockets which are needed for 

 the reception of the huge tusks. These sockets 

 extend nearly to the upper part of the head, and are 

 so long that when the mouth is closed, the lower 

 part of the socket is about level with the bottom of the 

 lower jaw. 



