Underground nest of dried grasses and other plant parts is constructed in burrow. Water is obtained metabolically from green vegetation and seeds, and from moisture in food. Suitable habitat for Bailey's pocket mouse includes scrub flats or slopes. Agricultural uses preclude its existence. Yearlong activity, although individuals may become torpid over short periods during high summer temperatures.
Pocket mice are aggressively solitary.
Territory size unknown but probably equal to home range. Litter size averages 5 young. Gestation is approximately 3-4 wk. Under favorable conditions, young of the year may breed successfully. Bailey's pocket mouse is a nocturnal granivore, inhabiting extremely xeric habitats of the Colorado Desert in California.