Canadian Beaver 
2. Roof Rat. Mus rattus alexandrinus (Geoffroy). Colours 
above brown and gray, below pure vellowish-white. Shape, 
ears and tail exactly as in the black rat. 
Range. In America, South Atlantic States. 
BEAVERS 
(Family Castoride) 
The beavers are our largest gnawing animals. They are 
heavily built and thoroughly adapted for an aquatic life, with 
their wonderful broad, flat, naked tail and webbed hind feet. Both 
fore and hind feet are four toed, but the second toe of the hind foot 
is peculiar in having two claws. 
In the structure of its skeleton the beaver differs from all 
the preceding ‘‘mouse-like” families and agrees with the squirrels 
and marmots in having the two bones which form the lower leg 
separate and not fused solidly together. 
We find in many groups of animals one or more members 
adapted for life in the water and the beaver is the aquatic re- 
presentative of the squirrel tribe, just as the muskrat is of the 
mouse family and the otter of the weasel tribe. 
Canadian Beaver 
Castor canadensis Kuhl 
Length. 44 inches. 
Description. Tail and feet as described above, ears short. Body 
thick and heavy, closely covered with fur. Colour dark bay 
or blackish-brown, hairs tipped with chestnut, becoming 
brighter on the head, sides of the neck and rump; ears black, 
feet, legs and underparts seal-brown. 
Range. Northeastern North America, now nearly extinct within 
the United States, represented to the South and West by 
slightly different geographic races. 
Beavers are creatures with whose life history everyone is supe 
posed to be more or less familiar; the outstanding features of their 
lives having been written and read over and over again by each 
ug 
