TUB BEAVER. 83 



are drift-wood, green willows, birch, and poplars, if they 

 can be got, and also mud and stones ; these are inter- 

 mixed without order, the only aim being to carry out 

 the work with a regular sweep, and to make the whole 

 of equal strength. Old dams by frequent repairing be- 

 come a solid bank, capable of resisting a great force of 

 water and ice, and as the willows, poplars, and birches 

 take root and shoot up, they form by degrees a sort of 

 thick hedge-row, often of considerable height. Of the 

 same materials the houses themselves are built, and in 

 size proportionate to the number of their respective in- 

 habitants, which seldom exceeds four old and six or eight 

 young ones. The houses, however, are ruder in struc- 

 ture than the dam ; the only aim being to have a dry 

 place to lie upon, and perhaps feed in. When the 

 houses are large, it often happens that they are divided 

 by partitions into two or three or even more compart- 

 ments, which have, in general, no communication, except 

 by water ; such may be called double or treble houses, 

 rather than houses divided. Each compartment is in- 

 habited by its own possessors, who know their own door, 

 and have no connexion with their neighbours, more than 

 a friendly intercourse, and joining with them in the ne- 

 cessary labour of building. So far are the beavers from 

 driving stakes, as some have said, into the ground when 

 building, that they lay most of the wood crosswise, and 

 nearly horizontal, without any order than that of leaving 

 a cavity in the middle; and when any unnecessary 

 branches project inward, they cut them off with their 

 chisel-like teeth, and throw them in among the rest to 

 prevent the mud from falling in. With this wood is 

 mixed mud and stones, and the whole compacted toge- 

 ther. The bank affords them the mud, or the bottom of 

 the creek, and they carry it, as well as the stones, under 

 their throat by the aid of their fore-paws ; the wood they 

 drag along with their teeth. They always work in the 

 night, and have been known during the course of a single 

 night to have accumulated as much mud as amounted to 

 some thousands of their little handfuls. Every fall they 

 cover the outside of their houses with fresh mud, and as 



