XXVII. ADAPTATION OF MAMMALS TO 

 VARIED CONDITIONS 



In glancing at the mammals, or milk givers, from the 

 ant-eaters to the apes, one is impressed by the remarkable 

 variety in shape and habit. Nature has adapted these 

 animals for nearly every possible condition — land, water, 

 or air. In the whales there are the rudiments of hind legs, 

 suggesting that these mighty animals, one hundred feet in 

 length, in certain instances weighing hundreds of tons, may 

 once in some early form have been semi-land animals and, 

 instead of going to sea, lived in shallow water, like the huge 

 rhytina, described by Steller — an animal with the tail of a 

 whale, the body of a sea lion or seal, found living in the 

 shallows of the Arctic Ocean, the last of its race. 



But the whale to-day is a sea-going milk giver, suckling 

 its one or two young, having a broad, fishlike tail placed 

 horizontally instead of vertically ; provided with enormous 

 layers of fat to resist the cold of deep water, enabled to hold 

 its breath for an hour if necessary ; in a word, adapted to a 

 fishlike life, and even having a top or dorsal fin in some 

 instances, as in the orca, this fishlike fin being six feet tall. 



Theoretically the whale does not need water ; it is an air- 

 breathing animal, has lungs hke any mammal, but its nos- 

 trils instead of being near the mouth or in front, as in the 

 cow, ape, or horse, are on top of the head — a wonderful 

 adaptation to its water habit. It is as necessary for the 

 whale to breathe air as it is for man, but while man 



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