180 CURIOUS HOMES AND THEIR TENANTS. 



Many races of valuable animals have been killed 

 off until none remain, many more are on the way and 

 traveling rapidly toward extinction, but certain spe- 

 cies that have developed sufficient individual intelli- 

 gence learn how either to successfully defy man or to 

 gain his friendship and protection. Others have de- 

 veloped along lines that make them so easily domes- 

 ticated and so useful that they, too, are preserved. 



English sparrows, rabbits, rats, roaches, mice, and 

 viler creatures live and multiply in spite of all that 

 human beings can do to extii-pate them. Dogs and 

 cats are useful pets. Horses, cattle, sheep, and goats 

 are indispensable, as are ducks and geese and poultry 

 generally, but most of the wild races of animals are 

 without doubt, with the beavers, doomed to become 

 extinct. 



Beavers are the only mammals that practice co- 

 operation; others, like prairie dogs and viscachus, 

 live together in communities ; but no others work in 

 common, as do beavers, for the benefit of the whole 

 community. 



The beaver colony select for its home a small 

 stream running through a forest or grove of trees, 

 consisting largely of willows, birches, and poplars, 

 upon the bark and buds of which the animals feed. 

 In order to get at the twigs and fresh shoots from the 

 limbs, of which they are very fond, the animals cut 

 down trees of almost all sizes. 



They do not, however, as is reported of them, fell 

 the trees in such a manner as to make them fall into 

 the water, where they can float them to the spot 



