PORPOISES 



CHAPTER I 



The Mammals of the North Atlantic 



Seals. 



The most abundant mammal of the shores of the North Atlantic 

 is the common seal (Phoca vitulina), the typical representative of a 

 group of Carnivora specially modified for an aquatic existence. This adaptation 

 is remarkably displayed by the limbs, which take the form of paddles, or flippers. 

 Seals are also distinguished from the land Carnivora by the number and structure 

 of their teeth, none of them having three pairs of front, or incisor, teeth in each 

 jaw, and none showing the so-called carnassial teeth characteristic of the more 

 typical flesh -eating mammals. Other features of the group are the absence of 

 collar-bones in the skeleton, the shortness of the tail, and the prominence of the 

 eyes. 



With the exception of a few which ascend rivers some distance above their 

 estuaries, and others inhabiting inland seas or lakes, seals are confined to the 

 sea, where they subsist almost exclusively on animal food, especially fishes, 

 molluscs, and crabs and lobsters of which they devour immense quantities. 

 Although all are fairly intelligent and easily tamed, the various kinds differ 

 considerably in their mode of life. The walruses and eared seals, for instance, in 

 which the males exceed the females in size, are polygamous animals, resorting 

 during the breeding-season to certain particular shores, where they remain for a 

 considerable part of the year. The typical, or earless, seals, on the other hand, for 



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