the ponderous character of the dams is remembered, and when it is
stated that some of them are more than an eighth of a mile wide.
Every log, after being gnawed off the proper length, is stripped
of its bark which is stored away for use as food during the winter.

The lodges of the beavers are composed principally of mud, moss and
branches, circular in shape, the space within being seven feet in
width and about half as high. The walls are so thick that on the
outside the corresponding dimensions are nearly three times as
great as within. The roof is finished off with a thick layer of
mud, laid on with wonderful smoothness and renewed every year. The
severe frosts of winter freeze the lodge into such a solid structure
that the beaver is safe against the wolverine, which is unable to
break through the wall, resembling the adobe structures found in
Mexico and the Southwest. Even the trapper who attempts to demolish
one of the structures finds it tiresome labor, even with the help
of iron implements.

The beavers excavate a ditch around their lodges too deep to be
frozen. Into this opens all their dwellings, the door being far
below the surface, so that free ingress and egress are secured.

The half dozen beavers occupying a lodge arrange their beds
against the wall, each separate from the other, while the centre
of the chamber is unoccupied. During summer they secure their stock
of food by gnawing down hundreds of trees, the trunks or limbs of
which are sunk and fastened in some peculiar manner to the bottom
of the stream. During the winter when the beaver feels hungry, he
dives down, brings up one of the logs, drags it to a suitable spot
and nibbles off the bark.