144 The Mammals of Colorado 
may have settled somewhat, as it was an old abandoned 
house. The thickness of the roof over the chamber was 22 
inches, and of the walls on either side 3 feet. A very large 
house in the same vicinity measured 17 by 22 feet on the water 
level, and 12 feet along the ridge on top; this was unusually 
large. 
The Beaver's food consists mostly, if not entirely, of the 
bark of trees and bushes. These it cuts down and gnaws 
the bark off at its leisure. Generally it cuts off the branches 
and drags them into the water, and works at them there, and 
it often stores large quantities of branches in the water for 
winter use. I found in a pond at Crested Butte willow brush 
thus stored for a distance of one hundred feet along the shore, 
in water four feet deep or more, and laid from the bottom 
to the surface. These willow branches were from three to 
seven or eight feet long, and it is easily seen that they represent 
a great amount of work, as well as a good supply of food. 
While the Beaver has always been credited with a sufficient 
amount of intelligence to fell a tree in any direction it wished, 
and with a certain amount of engineering skill, some of my 
observations indicate either a lack of intelligence or very 
poor judgment, for trees were badly felled when there was no 
excuse for it, and dams built which were simply labor thrown 
away from an engineering standpoint. 
Family SCmRID^ 
Arboreal or terrestrial forms of moderate size, with long cylindrical 
hairy tails without scales; skull with distinct postorbital processes 
and a small infraorbital opening ; palate rather broad ; premolars ^-y-^ 
first upper premolar always small, often deciduous or wanting; 
molars tuberculate and rooted. 
A large family found throughout the world except Aus- 
tralia. 
Key of the Genera 
A. Tail short, less than I total length; form stout and thickset; 
shallow cheek pouches. 
