Bear food becomes scarce as winter approaches. Fruit, berries, grass, and weeds are out of season; most birds and insects are gone. The bear feeds on what remains--small animals which he digs out, a stray stranded fish, now and then a dead bird or animal carcass, the red fruit of the rose, and the nuts, bark, and roots of trees and plants. I do not believe the grizzly eats a special or a purgative food during the few days preceding his denning up, although he may do so. On the few occasions when I have been able to keep track of a bear during the four or five days immediately preceding his retirement, he did not eat a single thing. I have examined a number of grizzlies that were killed while hibernating, and in every instance the stomach and intestines were empty. These facts lead me to conclude that bears rest and fast for a few days before going permanently to the winter den. The bear generally prepares his winter quarters in advance of the time needed. He may occasionally sleep in his den before taking possession of it for the winter. But this is exceptional. In two cases that I know of he lay outside the den, though near it; and a number of other times he kept away from the den until he entered it for the long sleep. After the den is completely ready, the grizzly continues his usual search for food. Generally this requires long excursions and he may wander miles from the den. In climbing along the bottom of a deep, narrow ravine one November day, I saw on the slope above me what appeared to be a carload or more of freshly dumped earth. My first thought was that a prospector was at work driving a tunnel; but upon examination it proved to be a recently finished but 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 determined by the character of the soil in which it is made and also by the inclination of the bear making it. Most other dens measured were smaller than this one.