COMMON SEALS. 



E now arrive at a very wonderful series of animals, which, although they breathe 

 atmospheric air like other mammalia, are yet almost entirely aquatic in their 

 habits, and are never seen except in the water or its immediate vicinity. The 

 first family of these aquatic mammalia is that which is formed of the animals 

 which are popularly known by the name of SEALS. 



The structure of their bodies shows that the Seals are intended to pass the 

 greater portion of their existence in the water, for the body is elongated, and 

 formed very much like that of a fish, while the limbs and feet are so modified that they 

 greatly resemble fins, and are put to the same use. 



In order to protect their bodies from the debilitating action of the element in which they 

 live, they are thjckly covered with a double fur, which, when immersed in water, is pressed 

 tightly to the skin, and effectually throws off the moisture. In some Seals this fur is 

 extremely valuable, and is largely employed as an article of commerce. The fur itself is kept 

 constantly lubricated with a fatty matter secreted by the skin, and is thus rendered water- 

 proof. The more effectually to defend the animal from the icy cold water in which it is often 

 immersed, and from the ice-fields on which it loves to climb, a thick layer of fat is placed 

 immediately below the skin, and being an excellent non-conductor of heat, serves to retain the 

 internal heat through the severest cold. All the fat of the body seems to be pressed into this 

 service, as there is comparatively little Of the internal fat that is usually found plentifully in 

 the mammalia. 



Aided by the imperfectly developed limbs, the Seals are able to leave the water and to 

 ascend the shore, where they are capable of proceeding with no small rapidity, though in a 

 sufficiently awkward manner, their gait partaking equally of the character of a shuffle and a 

 crawl. When moving in a direct line, without being hurried, they bend their spine in such a 

 manner as to give them the appearance of huge caterpillars crawling leisurely along the 

 ground ; the spine is extremely flexible, so that the animal can urge itself through the water 

 in a manner very similar to that which is employed by the fish. 



Their clumsy, scuttling movements when on land form a curious contrast with the easy 

 grace of their progress through the water. When the Seals swim, they drive themselves for- 

 ward by means of their liinder feet, which are turned inward, and pressed against each other 

 so as to form a powerful leverage against the water, as well as a rudder, by means of which 

 they can direct their progress. They are also assisted in some measure by the fore-limbs, but 

 these latter members are more employed upon land than in water, except perhaps for the pur- 

 pose of grasping their young. On reference to the skeleton of the Seal, shown on page 369, the 

 peculiar formation of the Seal's limbs will be better understood than by the expenditure of a 

 page of actual description alone. 



When they desire to leave the water, they rush violently towards the shore, and by the 

 force of their impulse shoot themselves out of the water, and scramble up the bank as fast as 

 they can. On taking again to the water, they shuffle to the edge of the bank, and tumble 

 themselves into the sea or river in a very unceremonious manner, gliding away as if rejoicing 

 that they were once more in their proper element. 



The food of the Seals consists chiefly of fish, but they also feed largely upon various 

 crustacea, and upon mollusks. Their powers of swimming are so great that they are able to 



