WHALES AND WHALING 297 



need not worry about being attacked by a whale, for 

 only one rare species, called the killer whale, ever 

 eats warm-blooded animals. Most whales live on 

 little shrimp and cuttlefish, which they strain from 

 the water by means of the whalebone attached to 

 their upper jaw. Their throats are so small that 

 they cannot swallow any animal as large as a man. 

 Two common species of whale, the sperm and the 

 white whale, have teeth instead of whalebone. 



Their skin is smooth and slick, having no hair or 

 scales. Immediately beneath the skin is a thick layer 

 of fat called blubber. This fat, being a poor con- 

 ductor, serves to retain the heat of the body, and 

 thus enables the huge warm-blooded animals to keep 

 warm in the icy waters of the temperate and frigid 

 zones. 



The whale has gradually developed from a 

 creature having legs. The flippers of the whale are 

 in fact fore limbs functionally reduced to mere pad- 

 dles with no power of motion except at the shoulder- 

 joint, although they have all the bones, joints, and 

 even most of the muscles of the human hand and 

 arm. 



They swim mainly by means of the tail, which 

 differs from that of most fishes, being expanded hori- 

 zontally in order to facilitate their continual up- 

 ward and downward motion. Nature has placed the 

 whale's nose on the top of his head, where he can 

 breathe easily without shoving his head out of the 

 water. 



Young whales are much larger than any other 

 babies, often weighing 16,000 to 20,000 pounds. 



