POLAR BEAKS. 131 



break in the roof, and seizes the young seal before it 

 can escape. The hunter does just the same thing, 

 except that he uses his dog's nose for the discovery, 

 and his spear instead of claws. 



The modifications of form which permit the Polar 

 Bear to become a trespasser upon the water are few and 

 simple, but effective for their purpose. As the animal 

 is not intended to remain below the surface for any 

 length of time, no change of structure is needed in the 

 respiratory organs. As, however, it is obliged to be 

 very active in the water, and to swim to long distances, 

 the means of locomotion must evidently be very different 

 from those of the terrestrial bears. 



In the first place, the body is longer and more 

 flexible, while the neck is so much elongated as to 

 remind the observer of the same part of a weasel, and 

 is almost as flexible as that of the otter, which has 

 already been described. Then, the head is of a rather 

 peculiar shape, tapering regularly from the forehead to 

 the nose, instead of having a depression at the base of 

 the snout, as is the case with land-inhabiting bears,- 

 this form being probably given in order to enable the 

 animal to dart its head faster at its prey than it could 

 do if it were" broad and thick. 



The chief instruments of locomotion are the feet, 

 which serve to transport the animal over land or ice, 

 or to propel it through the water. They are very much 

 longer and broader than those of the terrestrial bears, 

 measuring, in fact, one-sixth of the length of the body. 

 By means of these four paddles, the bear, in spite of 

 its large size, can play about in the water almost as 

 actively as the otter itself, and is so swift and quick 



