Pocket mice can be distinguished from similar smaller rodents by their externally opening fur-lined cheek pouches.

It is found in the Tehachapi Mountains and the lower slopes of the western Sierra Nevada at elevations of up to 600 m (2,000 ft).

[3] The San Joaquin pocket mouse feeds on seeds of grasses and various plants, carrying them back to its burrow in its cheek pouches.

It stores seed surplus to its immediate requirements in the chambers inside the burrow for use at times of year when food is scarce.

It seems to be secure within its range, and no particular threats have been identified except in the north, where agricultural development is destroying and fragmenting its habitat.