THE IMPENETRABLE SEA 



sometimes fairly large ones. The seal's breathing is ex- 

 tremely slow. When on land and fully active a period of 

 about two minutes elapses between each intake of breath 

 and the next. It can hold its breath for long periods — a 

 man would die in a quarter of the time that the animal 

 can completely suspend its breathing. This breath- 

 suspension power is of great use to the seal in pursuing 

 its prey. It has been known to remain under water for as 

 long as twenty- five minutes. 



The seal's nostrils can be completely closed, making 

 them watertight. So with its small hearing orifices. Its 

 eyes have remarkable optical peculiarities, enabling them 

 to be used with equal efiiciency both under water and 

 above the surface. 



Seals are usually grouped under two dissimilar types, 

 the so-called fur seals and the hair seals. The former may 

 remotely resemble bears, and are in fact often called 

 "sea-bears". The fur seal yields a valuable fur, but the 

 hair seal has no fur — its hide is used for leather and its 

 body yields a valuable oil. The hair seal inhabits the 

 Antarctic, North Atlantic and Arctic oceans, although 

 small groups are scattered over the globe. The fur seals 

 are more or less widely distributed throughout the 

 southern seas. The hair seal cannot walk or run on 

 land — it can only wriggle on its stomach — but the fur 

 seal can run or lope along the ground with considerable 

 rapidity. 



The brown seal has a way of sleeping that is, to say the 

 least, extraordinary. R. M. Lockley, studying seals in 

 aquaria in Germany, watched a pair of seals of this 

 variety sleeping in a glass tank containing about six feet 

 of water. The female closed her eyes first and was soon 

 fast asleep, on the floor of the tank, her breathing sus- 

 pended. After some moments the bull fell asleep, closing 

 his eyes and nostrils and slowly sinking to the bottom. 

 The cow seal then rose to the surface, with scarcely per- 

 ceptible movements of her flippers. Her eyes were fast 



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