150 THE WORLD OF ANIMAL LIFE 



The animal is often destroyed by the natives, who arm them- 

 selves with a harpoon, to which a long and stout rope is attached, 

 and with a number of sharp spears. When a hippopotamus is 

 seen wallowing in a river, one of the most experienced of the 

 hunters rows to the spot and plunges the harpoon deeply into 

 its body. The end of the rope is then made fast to a tree, and 

 the other hunters surround the wounded animal and hurl spear 

 after spear at him as often as he rises to the surface, until he 

 perishes from exhaustion and loss of blood. 



The death of a hippopotamus is always hailed by the natives 

 with great delight. In the first place, his flesh furnishes them 

 with an abundant supply of food, on ^\'hich they can feast heartily 

 for several days. Out of his hide, which is no less than an inch 

 and a half in thickness upon his back, they make long whips, 

 which are used in driving cattle; while, thirdly, his tusks furnish 

 a supply of excellent ivory, which can be sold at a high price to 

 the traders. Of this ivory artificial teeth are often made. 



The hide of a hippopotamus is always covered with a kind 

 of natural oil, which exudes through the pores in the skin, and 

 appears to preserve the animal from the injurious effects of long- 

 continued immersion in the ^\■ater. The ears and nostrils, like 

 those of the seal, are closed as soon as the head is plunged 

 beneath the surface. 



THE CETACEA 



The Cetacea, which include the whale, the dolphin, the 

 porpoise, etc., are mammals that live entirely in the sea, and 

 are therefore thought by many to be fishes. They are warm- 

 blooded animals and breathe air and not water like the fishes. 

 Yet in form they are very like fish. This fish form is necessary to 

 enable them to move quickly through the water in order that they 

 may overtake their prey, and also for their own safety. As ordinary 

 limbs would be very much in their way, they are not provided 



