THE CANADIAN BEAVER 313 
observation shows, there is but one claim which has 
been seriously made for the beaver’s sagacity which is 
matter for doubt. It has been asserted that the 
animal always cuts the trees it selects, so that they 
may fall towards the water. There is evidence that this 
is not always the case. But trees growing near the 
water naturally tend to lean towards the stream, and 
naturally extend the heaviest growth of branches over 
the water, where light and space are greatest, and the 
greater number of those cut by the beavers would 
probably fall in that direction without any special 
provision. But the inseparable features of a beaver- 
colony, the dyke or “ dam,” and the less famous 
but almost equally wonderful “ canal,” suggests an 
estimate of brain-power or inherited instinct for 
mechanics which an exhaustive examination of the 
facts heightens rather than diminishes. 
The object of the dam is to supply a temporary 
want, not a permanent necessity always present to 
the beaver-mind. In summer, the beavers wander 
up the streams, finding food without difficulty. In 
winter, they require a permanent supply of water at 
a certain level, in which they can swim beneath the 
ice, store their supply of branches for food so as to 
be accessible without exposing themselves, and keep 
a “ moat ” round their lodges. Left to itself, the 
stream would run low in winter, when the freezing 
of the snow and earth stops the water-supply. 
Hence the necessity for the dam to maintain it at a 
constant level. Such a train of arguments supposes 
