170 ANIMAL LIFE IN THE YOSEMITE 



the mouth of the burrow the rapidity with which a squirrel can drop into 

 its retreat is surprising. Once scared into the ground it stays only a short 

 time, then pokes its head out again, to just below the level of its eyes. 



When sitting erect and observing its surroundings a squirrel can often 

 be seen to twitch its nose as if sniffing and drawing in the air. Probably 

 it uses the sense of smell to aid its powers of sight and hearing. 



On flat open land where grass is at best yery short, the usual mode of 

 progression for this squirrel is a heavy run, with little up and down move- 

 ment of the body, and with the tail down. In high grass, instead of parting 

 the stalks and running between them, the squirrel progresses by a series 

 of jumps ; each hop carries the animal up so that it can look about for some 

 distance and be able to spy an approaching enemy. 



Once a Belding Squirrel was come upon in a rocky place ; the animal 

 ran over some rocks and jumped over a creek which was fully 2 feet wide, 

 in its effort to escape. Another, on Mount Hoffmann, ran along the face 

 of a pinnacle of rock, clinging to small cracks in the surface. 



The Belding Ground Squirrel subsists chiefly upon grass and grass 

 seeds, and depends less upon the larger seeds, nuts, and roots such as are 

 eaten by the California Ground Squirrel and the chipmunks. When feed- 

 ing, the animal sits in a hunched-up position, the hind legs in entire support 

 of the body. The forefeet, when grass is being eaten, are used to draw the 

 grass stalks or heads toward the mouth where they can be cut off. Larger 

 items are held in the forepaws, while small pieces are nibbled off with the 

 front (incisor) teeth and rapidly ground up by the cheek teeth (molars). 

 In a few instances Belding Squirrels were captured in meat-baited traps 

 set for carnivores. Certain other members of the squirrel family seek 

 flesh bait when available, but the present species seems to be more restricted 

 in its food preferences to vegetable material. At the mule corral on 

 Tuolumne Meadows in 1915 the 'picket-pins' were foraging around barley 

 sacks, gleaning scattered grain like rats. Several Belding Squirrels were 

 caught in steel traps set in the entrances to Marmot burrows, and one was 

 captured in a Macabee gopher trap which had been set in a gopher burrow. 



Each 'picket-pin' evidently restricts itself closely to use of its own par- 

 ticular burrow and does not, in time of danger, dart into whatever retreat 

 happens to be nearest at hand. On Lyell Meadows one was repeatedly seen 

 to run from the meadowland, where there were numerous holes, to a par- 

 ticular burrow in the granite gravel above the trail. Near the same place, 

 one of our party suddenly came upon one of these squirrels, posted at 

 'observation,' within one foot of an open burrow. The squirrel, instead 

 of darting into this nearest hole, ran to one fully 30 feet farther away. 



The burrows are usually constructed right in the meadows which furnish 

 the animals their food ; less frequently they are dug in the rocky soil at 



