not yet occupied hibernating-den. The entrance 

 was about three feet in diameter. Just inside the 

 den was a trifle larger. It extended, nearly level, 

 about twelve feet into the mountain-side. At the 

 back it was six feet across and four feet high. 



The size of the den varies and is apparently de- 

 termined by the character of the soil in which it is 

 made and also by the inclination of the bear mak- 

 ing it. Most other dens measured were smaller than 

 this one. 



The grizzly may use the same den for several 

 winters or have a new one each year. He may dig 

 the den himself or take an old one that some other 

 bear has used, or he may make use of one shaped 

 by Nature a cave or a rock-slide. I knew of one 

 grizzly hibernating in a prospector's abandoned 

 tunnel. Sometimes, like the black bear, he will dig 

 a den on a steep mountain-side beneath the widely 

 spreading roots of trees; sometimes beneath a 

 large fallen log, close to the upturned roots which 

 support it. In crossing the mountains one Febru- 

 ary I noticed a steamy vapor rising from a hole in 

 the snow by the protruding roots of an overturned 

 tree. I walked to the hole to investigate. The vapor 

 was rank with the odor of a bear. Near my home on 

 84 



