The Desert Tortoise, Gopherus agassizii, is a species of tortoise native to the Mojave Desert and Sonoran Desert of the southwestern United States and northern Mexico. The epithet agassizii is in honor of Swiss-American zoologist Jean Louis Rodolphe Agassiz.
The carapace of these tortoises may attain a length of 6 to 15 inches, with males being slightly larger than females. Their shells are high-domed, and greenish-tan to dark brown in color. Desert tortoises can grow from 4″“6″ in height and weigh 8″“15 lb when fully grown. The front limbs have heavy, claw-like scales and are flattened for digging. Back legs are more stumpy and elephant-like.
The Desert Tortoise is capable of living in areas where the ground temperature may exceed 140 degrees because of its ability to dig underground burrows and escape the heat. Almost all of its life is spent in burrows. These burrows are also beneficial to other reptiles, mammals, birds and invertebrates. It is believed that, in their entire lives, these tortoises rarely move more than two miles from their natal nest.
This tortoise is a herbivore. Grasses form the bulk of its diet, but it also eats herbs, annual wildflowers, some shrubs, and new growth of cacti, as well as their fruit and flowers. Rocks and soil are also ingested, perhaps as a means of maintaining intestinal digestive bacteria and/or as a source of supplementary calcium or other minerals. Adult tortoises can survive a year or more without access to water.
The mating season for the desert tortoise occurs from spring to fall, with a peak in late summer to early fall (September). They typically lay 4-8 eggs per clutch, with 1-2 clutches per year. The eggs are hard, chalky and elliptical or spherical and buried in a funnel-shaped nest. They are incubated for 90-120 days. Hatchlings from only a few eggs out of every hundred actually survive the 7-15 years it takes to reach full adulthood. The desert tortoise can weigh from 8-15 lbs.