In this lake, produced by their art, the beavers build their houses, which are generally of three storeys, though at times of four. They are round and pointed like a sugar-loaf, are about twenty feet in diameter at the bottom of the water; the floors are about two feet high, and separated by a flooring, in the centre of which is a round hole, by means of which they go up and down the house. The only entrance is at the bottom of the water, and generally only the highest floor emerges from the water, so that the latter is always dry. The creatures build their house of branches three feet in length, which they bind together with twigs and earth, and make the walls nearly a foot thick. They thus build one floor over the other, each higher one being smaller, till the highest one terminates in a point. They line the interior with grass and moss, so that it affords them and their young a dry, warm abode in winter. [Illustration: BEAVERS BUILDING A DAM. _p. 268._] The females give birth at the end of May, or beginning of June, to from two to six young, which are brought up in the colony and remain there; on the other hand, they never admit a strange beaver, and fight sanguinary battles with it, if it tries to force its way into their settlement. In proportion as the family increases, more houses are built, and I have often seen lodges in which a dozen houses peeped out of the water. The beavers, however, do not fell the trees solely to build their houses, but also to procure food from the tender bark of the thinner branches. They convey these branches in autumn, cut in lengths, to their houses, and pile up a large supply in the lower rooms, on which they live in winter. They go on land at this season, too, and for this purpose keep holes open, in the ice on the banks of their ponds, and I have also found their track in the snow; but as a rule, they remain at home at that season. If the family grow too numerous for the space and the food to be found in the vicinity, several members of it emigrate and establish a new lodge close by: frequently an old beaver colony will contain a hundred. The beaver is one of the most cautious and timid animals in creation, and it is very difficult to get at it on land and kill it with firearms; on the other hand, it is wonderfully easy to capture in traps, and in this way an entire colony can be extirpated to the last one in a very short period.