THE MAMMALS 211 



The demand for many animals on account of their hides 

 and fur has led to a great decrease in their numbers; some, 

 such as the pumas, bears, wolves and wild cats have been 

 rapidly killed off, partly because of their attacks upon 

 domestic animals, partly for the sport of hunting. The 

 species, such as the deer, which supply food are rapidly 

 going. But among the most efficient of the destructive 

 agencies is the wanton killing by hunters for mere sport. 

 For years there has gone on in Africa a fearful slaughter 



FIG. 163. Platypus or duck-bill, Ornithorhynchus anatinus. (After Gould.) 



of elephants, rhinoceri, antelopes, zebras, giraffes, hippo- 

 potimi, gorillas, etc., that has greatly reduced the number 

 of these fine species, so that several of them are threatened 

 with extinction. Many of our finest North American 

 mammals such as the moose, elk, and grizzly bear are com- 

 paratively few in numbers and much restricted in range. 

 The class Mammalia is divided into several orders. 

 The lowest of these, the Monotremes, have the remarkable 

 peculiarity of laying eggs, like the birds and most reptiles, 

 instead of bringing forth living young. The order com- 



