182 ANIMAL LIFE IN THE YO SEMITE 



plants in the way of seeds actually consumed. The manner in which the 

 chipmunks relocate stores which have been buried is not known definitely, 

 but the sense of smell is probably of important service. 



The chipmunks, constituting a group of rodents usually thought of 

 as tree-dwelling animals, are in reality more closely related to certain of 

 the ground squirrels than to the tree squirrels. One feature possessed in 

 common is the cheek pouch. This is a thin membrane-like sac, one on each 

 side of the face beneath the outer furry skin and opening inside the mouth. 

 Seeds or nuts can be passed from the mouth to the pouches or vice versa 

 merely by action of the cheek muscles and tongue, without aid from the 

 forepaws. The Gray and Red squirrels have no cheek pouches of any 

 sort. 



When foraging, the Tahoe Chipmunk is likely to be seen in a wide 

 variety of situations. In the Canadian Zone it was often noted climbing 

 about in different sorts of brush plants to gather the seeds or fruits. Some 

 food, such as scattered pine seeds, certain kinds of fungi, and scraps from 

 persons' lunches is sought on the ground. In the fall months many differ- 

 ent members of the squirrel family busy themselves in harvesting grass 

 seed, and the Tahoe Chipmunk was sometimes seen s© engaged. At Porcu- 

 pine Flat, in late June, the animals were at work on the cones of the 

 lodgepole pine. At Ten Lakes, in October, two of these chipmunks which 

 had their faces smeared with pitch were encountered, suggesting that the 

 animals had been working on unripe cones. 



The contents of the cheek pouches of 10 individual Tahoe Chipmunks, 

 collected for specimens, were saved by us for analysis. In 6, seeds of 

 coniferous trees exclusively were represented ; in 5 of these cases the seeds 

 were those of the Jeffrey pine, the remaining one being (doubtfully) of 

 the lodgepole pine. The numbers of pine seeds which were contained in 

 the cheek pouches of individual animals varied from 1 to 20, the latter 

 (of Jeffrey pine) constituting seemingly the full capacity of the two cheek 

 pouches of a chipmunk. 



The other 4 sets of contents of cheek pouches gave analyses as follows: 

 (1) Fragments of a brown-colored fungus; (2) 62 hulled seeds of a grass, 

 probably wild brome; (3) 90 seeds of black bindweed (an introduced 

 plant) ; (4) a mixed lot of seeds including those of a geranium, a phacelia, 

 a borage, and a sedge. 



The season of activity for this chipmunk extends through the greater 

 portion of the year. Even the light snows of early winter do not drive all 

 the individuals into hibernation, although they probably all disappear with 

 the first heavy snowfall of the season. In the spring, they are out and 

 active when travelers are first able to climb to the higher levels, in May. 

 The little fellows are then to be seen skipping over the packed snow banks 

 between logs and tree trunks with no seeming discomfiture. 



