226 THE INDUSTRIES OF ANIMALS. 



fleeing from enemies who are too strong for it, and 

 depriving itself of a dangerous comfort. But when 

 the security of solitude permits these animals to 

 unite in societies, and to possess, without too much 

 fear, a pond or a stream, they then exhibit all their 

 industry. 



They build very well arranged dwellings, although 

 at first sight they look like mere piles of twigs, 

 branches, and logs, heaped in disorder on a small 

 dome of mud. At the edge of a pond each raises 

 his own lodge, and there is no work by the colony in 

 common. If, however, there is a question of inhabit- 

 ing the bank of a shallow stream, certain preliminary 

 works become necessary. The rodents establish a 

 dam, so that they may possess a large sheet of water 

 which may be of fair depth, and above all constant, 

 not at the mercy of the rise and fall of the stream. A 

 sudden and excessive flood is the one danger likely to 

 prove fatal to these dykes ; but even our own con- 

 structions are threatened under such circumstances. 



When the Beavers, tempted by abundance of 

 willows and poplars, of which they eat the bark and 

 utilise the wood in construction, have chosen a site, 

 and have decided to establish a village on the edge of 

 the water, there are several labours to be successively 

 accomplished. Their first desire is to be in possession 

 of a large number of felled trunks of trees. To 

 obtain them they scatter themselves in the forest 

 bordering the stream and attack saplings of from 

 twenty to thirty centimetres in diameter. They are 

 equipped for this purpose. With their powerful 

 incisors, worked by strong jaws, they can soon gnaw 

 through a tree of this size. But they are capable of 

 attacking trees, even more than lOO cc. in circum- 



