| California chipmunks typically live at elevations of 1,200-2,500 m in habitats where vegetation is sparse but rocks are plentiful. They use cracks in the rocks, or burrows dug under them, for food storage and nests. In late summer, the chipmunks climb pinyon pine trees to harvest the nuts, stuffing them into their cheek pouches to carry home. Chipmunks have cheeks similar to ours - quite a lot can be stuffed into them - but they do not have the kind of cheek pouches that some of their relatives have, such as the aptly named pocket gophers and pocket mice.
Allen, J.A., 1890. A Review of some of the North American ground squirrels of the genus Tamias, p. 70. Bulletin of the American Museum of Natural History, 3:45-116.
Mammal Species of the World
Mammalian Species, American Society of Mammalogists' species account