88 THE BEAVER 
Dugmore suggests that canals may have had their origin 
in the use of short natural openings in the shore of a pond, 
which were gradually extended, and finally the beavers 
learned to build canals wherever they wished, if feasible. 
It will be seen from the foregoing that there are many 
variations in the construction of canals, and some in their 
uses. Not all colonies have canals, for of course they are 
not always necessary, but when made they are adapted to 
their intended purposes, whether to bring logs some dis- 
tance from the pond, or to serve as a connection between 
two ponds. They are so notable that one can not refrain 
from expressing surprise at such things being done by animals 
having no tools but their fore paws, and the mental faculties 
of which, according to some, are no more than a highly 
specialized instinct. 
TRAILS AND LANDING PLACES 
In pursuing their activities on shore, beavers often make 
well defined paths or trails, which, when in use for a con- 
siderable length of time, may become deeply worn. As 
many, if not all the trails, are used by the beavers in carrying 
logs and brush, this material is probably responsible for 
most of the cutting down of the path. While I think it 
somewhat doubtful if the animals really lay out a road and 
clear it before beginning to use it, though some have stated 
that such is the case, they do cut out any roots, branches or 
logs which may interfere with their work. I have seen a 
four inch stick which had been cut through and part of it 
pulled to one side of a trail. Rotten logs lying across a 
trail are broken and worn by the sticks dragged over them. 
Conversely, trails sometimes pass under fallen logs which 
are lying high enough above ground not to interfere with the 
beaver going beneath. I saw one trail which went under 
eight logs in a distance of twenty feet (Fig. 39). Johnson 
