ANIMALS OF NORTH AMERICA. 
63 
the most correct and free from exaggeration, which has ever 
been published. 
u Where beavers are numerous they construct their habi- 
tations upon the banks of lakes, ponds, rivers and small 
streams ; but when they are at liberty to choose, they always 
select places where there is sufficient current to facilitate the 
transportation of food and other necessaries to their dwellings, 
and where the water is so deep as not to be frozen to the 
bottom during the winter. 
The beavers that build their houses in small rivers and 
creeks, in w T hich the water is liable to be drained off, when 
the back supplies are dried up by the frost, are wonderfully 
taught by instinct to provide against that evil, by making a 
dam quite across the stream, at a convenient distance from 
their houses. The beaver dams differ in shape according to 
the nature of the place in which they are built. If the water 
in the stream have but little motion, the dam is almost 
straight ; but when the current is more rapid, it is always made 
with a considerable curve, convex toward the stream. The 
materials made use of are drift wood, green willows, birch and 
poplars, if they can be got ; also mud and stones, intermixed 
in such a manner as must materially contribute to their 
strength. In places which have been long frequented by 
beavers undisturbed, their dams by frequent repairing, be- 
come a solid bank, capable of resisting a great force both of 
water and of ice. The beaver houses are built of the same 
materials as the dams, and are always proportioned in size 
to the number of inhabitants. Instead of order and regu- 
lation being observed in rearing their houses, they are of 
much ruder structure than their dams ; for it has never been 
observed that they aim at any other convenience in their 
houses, than to have a dry place to lie on. It frequently 
happens that some of the larger houses are found to have one 
or more partitions, if they deserve that appellation; but it is 
no more than a part of the main building, left by the sagacity 
