262 AUDUBON THE NATURALIST, 
have notice of the approach of winter weather, 
and of its probable severity, by observing the 
preparations made by the beavers to meet its 
rigours; as these animals always cut their woud 
iu good season, and if this be done early, winter 
is at hand. 
The beaver dams, where the animal is at all 
abundant, are built across the streams to their 
very head waters. Usually these dams are 
formed of mud, mosses, small stones, and 
branches of trees cut about three feet in length 
and from seven to twelve inches round. The 
bark of the trees in all cases being taken off+ 
for winter provender, before the sticks are car- 
ried away to make up the dam. The largest 
tree cut by the beaver, seen by Prevost, meas- 
ured eighteen inches in diameter; but so large 
a trunk is very rarely cut down by this animal. 
In the instance just mentioned, the branches 
only were used, the trunk not having been 
appropriated to the repairs of the dam or 
aught else by the beavers. 
In constructing the dams, the sticks, mud, 
and moss are matted and interlaced together 
in the firmest and most compact manner; so 
muck so, that even men cannot destroy them 
without a great deal of labour. The mud and 
moss at the bottom are rooted up with the 
animal's snout, somewhat in the manner hogs 
