SEALS. 503 



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 thickly 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 waterproof. 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 ex- 

 cellent 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 com- 

 paratively 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 caterpil- 

 lars 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 forward by means of their hinder 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 purpose of grasping their young. On reference 

 to the skeleton of the Seal on page 511, 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 consist chiefly of fish, but they also feed largely upon various 

 Crustacea, and upon molluscs. Their powers of swimming are so great that they are able 

 to urge successful chase of the fish even in their native element, and it has several times 

 happened that captive Seals have been trained to catch fish for the service of their 

 owners. 



The " whisker " hairs are extremely thick and long, and in many species are marked 

 with a raised sinuous margin, which gives them the appearance of being covered with 

 knobs. Their basal extremities are connected with a series of large nerves, similar to 

 those of the lion's lip, which has already been figured on page 137, and it is very prob- 

 able that this structure may aid them in the capture of their finny prey. The sense 

 of smell is largely developed, and the tongue is rough, and slightly cleft at its ex- 

 tremity ; the reason for this structure is not known. 



The brain of the Seal is very large in propotion to the body, and, as might be 

 expected from this circumstance, the creature is extremely intelligent, and is capable 

 of becoming very docile when placed under the tuition of a careful instructor. The 

 eyes are large, full, and intelligent, and the nostrils are so formed that they can be 

 effectually closed while the creature is submerged beneath the surface of the water, 

 and opened as soon as it rises for the purpose of respiration. At every breath the 

 nostrils open widely, and seem to close again by means of the elasticity of the sub- 

 stance of which they are composed. The ears are also furnished with a peculiar 

 structure for the purpose of resisting the entrance of water. 



