California
Gopherus agassizii  Jo-Ann Ordano, California Academy of Sciences | |
| Type of Animal: | Reptiles |
|---|---|
| Class: | Reptilia |
| Order: | Testudines |
| Family: | Testudinidae |
| Federal Status: | Threatened |
| State Status: | Threatened |
| Occurrence: | |
| Habitat: | Deserts,Oases,Dunes |
| Description: | Desert tortoises have existed for three million years, and during that time they have adapted to the many climatic and geological changes that have occurred in southern California. They can live in almost any type of desert habitat, but they do require crumbly soils in order to build burrows and nests. They are most common in desert areas with an abundance of creosote, and they are least common in desert areas with steep slopes. Tortoises are most active between March and June. In late summer the temperatures become too warm and they spend the majority of their time in their burrows. Desert tortoises are very sensitive to the heat, and exposure to the extreme desert temperatures can kill them in less than one hour. They hibernate during the winter months. Desert tortoises are herbivorous. They eat a variety of desert plants, although forbs and green vegetation are their preferred foods. They will drink water if it is available, but they get most of the water they need for survival from the plants they eat. The breeding season occurs in April, shortly after the tortoises emerge from hibernation. Females lay one to three clutches of about five eggs each in May, June, or July. The eggs hatch three to four months later. During dry years, desert tortoises often fail to reproduce due to lack of food. Adult tortoises have very few predators due to their protective carapace. Occasionally, a desperate coyote may attack a tortoise. Young tortoises are more vulnerable and are preyed upon by eagles, foxes, and coyotes. In captivity, many tortoises fall victim to an upper respiratory disease. Many human-related activities, discussed below, have resulted in the listing of this species as both federally threatened and state threatened. |
| Effort: | Although the desert tortoise population remained healthy for three million years, it is now experiencing a serious decline. One cause for this decline is an upper respiratory disease. This disease is usually found in captive pet tortoises, but some pet owners have released their sick tortoises into the wild. As a result, some wild tortoises have contracted and spread the disease. Raven predation on the young has also increased, and a series of droughts has resulted in a lack of reproduction to maintain the population. In addition to these causes, many tortoises have been collected illegally and human activities have destroyed much of their native habitat. The Bureau of Land Management (BLM) has joined with other organizations such as the U.S. Fish and Wildlife Service and the Desert Tortoise Preservation Committee in an effort to help this species. BLM employees work to uphold the provisions of the Endangered Species Act. Under this Act, listed species may not be harmed, harassed, pursued, hunted, wounded, killed, trapped, or collected. In 1976, the BLM and the Desert Tortoise Preservation Committee formed the Desert Tortoise Natural Area. This area is fenced off and is closed to all recreational activities except wildlife viewing. Three nature trails were created to allow visitors to view the tortoises without disrupting the entire area. The public can help the recovery of this species in a variety of ways. First, when visiting the Desert Tortoise Natural Area, remember to stay on the trails. Use binoculars to view these incredible animals if they are far away. This area was created to preserve the natural habitat. Second, when visiting the desert be aware of your surroundings. Desert tortoises seek shade in hot weather, and they occasionally find shade under a parked car. Desert tortoises have also been spotted crossing roads, so drive carefully. For more information on desert tortoises, including information about having them as pets, please click on the "Desert Tortoise Info" link below. |
| References: | Behler et al. 1979. National Audubon Society Field Guide to Reptiles and Amphibians. Stebbins 1985. Peterson Field Guide to Western Reptiles and Amphibians, Second Edition. Zeiner et al. (editors). 1988. California’s Wildlife, Volume I, Amphibians and Reptiles. |
| Other Sites: | DesertTortoise.gov - Desert tortoise do's and don'ts |
| Field Office(s): | Barstow; Needles; Palm Springs; Ridgecrest |