In late spring, tortoises may also be active in late afternoon. In summer, the best time to see them is during or after a thunderstorm. In the eastern Mojave and Colorado deserts, tortoises may also have a summer activity period, which is associated with summer rains and a summer food supply. Hibernation for a tortoise is a period of inactivity, generally below ground in a burrow or den. The heart rate, respiration rate and all bodily processes are slowed.
Tortoises are selective in choice of foods.
Foot preferences depend on locality and availability of food items. In general, tortoises in California feed on annual wildflowers, such as blazing stars, lupines, loco weeds, lotus, Indian wheat, forget me-nots, desert dandelions, gilias, phacelias, coreopsis, alkali goldfields and many other species. They also eat annual and perennial grasses and fresh pads and buds of some species of cactus. After the annual wildflowers have dried in spring, tortoises will eat the dried plants throughout late spring and into summer and fall. Consumption of dried plant material is somewhat dependent on the tortoise's state of hydration, and whether the tortoise has recently drunk water.