THE BEAVER. 165 
bottom to be laid upon them, and which gradually 
become cemented into a firm and compact mass. All 
their work is performed during the night. Although 
the favourable nature of the situation may have induced 
many families to assemble in the same spot, they do 
not on that account carry on their operations in com- 
mon; unless when a dam of large extent is to be built, 
when they usually unite their forces for its completion. 
Each family occupies itself exclusively on its own 
habitation, which has in general but one apartment. 
he idea of their houses being divided ito several 
chambers, each allotted to its appropriate purpose, 
may have originated from the fact of their sometimes 
building by the side of a deserted dwelling, with which 
they occasionally open a communication. The families 
vary in the number of individuals of which they are 
composed, but seldom exceed two or four old ones, 
and twice as many young; the females producing once 
a year, from two to three or four at a birth, and the 
young ones generally quitting their parents at the age 
of three years, and seeking out or building a separate 
habitation for themselves. 
In summer time they feed either upon the bark of 
trees or upon the green herbage and the berries which 
grow in their neighbourhood; but in winter their diet 
it almost restricted to the former article, of which they 
lay in a large stock previously to the setting in of the 
frost. From this store they cut away portions as their 
necessities require ; and after tearing off the bark reject 
the wood, leaving it to float away with the current. 
Willow, poplar, and birch, are their favourite kinds, 
and the latter, according to Cartwright, renders their 
flesh “the most delicious eating of any animal in the 
known world.” The root of the water-lily also affords 
them an occasional supply, and makes them very fat, 
but gives their flesh a strong and unpleasant flavour. 
