In the Sonoran Desert of Arizona, however, the tortoises tend to live on steep, rocky hillside slopes in Palo Verde and Saguaro Cactus communities. Other herbs, grasses, some shrubs and the new growth of cacti and their flowers comprise a major portion of the diet. If there is summer rain, tortoises will utilize dry forage. Females store sperm and egg laying occurs May, June and July. The number of eggs varies.
Female size seems to be one factor.
Hatchlings from only a few eggs out of every hundred actually make it to adulthood. Nests are often dug near the burrow opening early in the season and farther inside, late in the season. Some nests are dug away from the burrow but usually under a shrub. After laying, the female leaves the nest and the soil temperatures support growth of the embryos. Incubation periods of 90 to 120 days are typical.