FIN-FOOTED CARNIVORES 59 



seas. This powerful animal reaches a length of from 17 to 19 feet, and 

 may weigh as much as 3,000 pounds. Its limbs are longer than those of 

 the seal, and the hind-limbs can be bent round towards the belly. The 

 animal, accordingly, can walk, though awkwardly, after the fashion of 

 land animals. Its food consists principally of shell-fish, which it either 

 tears off from the rocks by means of its two powerful projecting tusks 

 (i.e., the two upper canines) or rakes up from the sea-bottom, using its 

 tusks as a kind of two-pronged rake, The upper lip is covered with 

 horny bristles of about the thickness of a quill. These act as a kind of 

 sieve for separating the shell-fish from the mud in which they are em- 

 bedded. Their hard shells it crushes with its broad-crowned molars 

 (compare with the duckbill). 



The walrus frequently attacks man, even when not provoked, and 

 great caution is necessary lest this ocean giant, with' one blow of his 

 powerful tusks, shatter the side of a boat. It will even defend itself on 

 land, unlike most other members of this family, which generally allow 

 themselves to be driven far inland to the killing-places, where they are 

 despatched with ease by a blow on the nose with a club. Formerly the 

 walrus was killed only for the sake of its tusks, which furnish a good 

 kind of ivory, but nowadays the skin and blubber of this, as of the other 

 species of the seal family, are also turned to account. 



ORDER V.: BATS (CHIROPTERA). 



A FLYING membrane extends between the long fore-limbs and the short 

 hind-limbs. The dentition consists of all three kinds of teeth. Insect 

 or fruit eating animals (insectivorous or frugivorous). Nocturnal or 

 crepuscular in their habits. 



The Long-Eared Bat (Plecotus auritus). 



(Body and tail each about 1 J inches long ; width from tip to 

 tip of extended flying membrane about 10 inches.) 



This animal derives its name from the conspicuously large external 

 ears. 



Bats pass a great portion of their lives traversing the air in search of 

 food (see Section B.). They thus have to bear the whole weight of their 

 body (compare with land and water animals), and often even their young, 

 which hang on to the breast of the mother until they are able to go in 

 search of their own food. Their mode of locomotion, then, is quite 

 different from that of all other mammals, and we need therefore feel no 

 surprise that their body is constructed in many ways quite differently. 



