Desert Tortoise

Scientific Name: Gopherus agassizii. Gopherus refers to their burrowing nature. Agassizi is in honor of the zoologist Louis Rodolphe Agassiz, who studied North American turtles and tortoises.

Description: Greenish-brown or tan, these adult tortoises can get up to 14” long, with males usually being bigger than females. Average height of an adult is 4-6” at the apex of their highly domed shell. The weight range for adult desert tortoises is 8-15 pounds.

Behavior: Desert tortoises are ectothermic and rely on their environment to regulate their body temperatures. Burrows, rocky shelters, and depressions in the soil (pallets) are their primary residences. Most of their lives are spent in burrows or shelters. Not all shelters are dug by tortoises themselves; burrows dug by other species such as squirrels, woodrats, burrowing owls, and Gila monsters have been found to be shared with desert tortoises.

These tortoises reach sexual maturity at 15-20 years of age due to their slow rate of growth. This growth rate also allows for a varied lifespan of 50-80 years. Mortality is due to human encroachment on habitat, disease, and environmental factors like drought or floods.

Diet:  Desert tortoises are herbivores, with grasses making up most of their diet. Because the presence of water is scarce in their environment, most of their moisture comes from their food intake, with spring grasses and wildflowers making up most of their water requirement. When water is present, these tortoises will drink large amounts of water–up to 40% of their body weight–at one time.

Range and Habitat: Endemic to the the Mojave and Sonoran Deserts of the United States and Mexico, these tortoises and their subspecies can be found in western Arizona, southeastern California, southern Nevada, and southwestern Utah as well.

Conservation: Aside from natural predation, a major threat to desert tortoises is human encroachment on their environment. Urbanization, disease, habitat destruction, and illegal collection have impacted the decline of desert tortoises in some areas by 90% since the 1980s. Desert tortoises in the Mojave region are listed as threatened under the Endangered Species Act of 1973.

How you can help: Do not touch, harass, or collect wildlife you may encounter. Desert tortoise populations are impacted by individuals being removed from their habitat to be pets or companion animals.