The desert tortoise can be found in the deserts of the southwestern United States and northern Mexico, specifically the Sonoran Desert and the Mojave Desert. These tortoises can withstand extremely hot temperatures. They are expert diggers able to dig underground burrows allowing them to escape the heat.
The burrows also provide insulation at night and in the winters, when temperatures are cool. Desert tortoises spend at least 95% of their lives in burrows.
Desert tortoises live in the Primm Valley. In this area they are known as Mojave Desert tortoises, due to the location. Mojave desert tortoises live up to an elevation of 3,500 feet. Their habitat ranges from sandy flats to rocky foothills. They prefer areas where soils are softer for construction of their burrows.
Desert tortoises prefer to stay in their same burrows for years, as they grow accustomed to food sources, water sources, and potential dangers. Desert tortoises can live to be 100 years old. However, due to loss of habitat, predation and disease, the Mojave Desert tortoise is a threatened species.
Desert tortoises are herbivores. They eat a variety of plant life including grasses, wildflowers, herbs, and new cacti growths. Desert tortoises also eat soil and rocks for digestive purposes and minerals. Because they live in desert regions, desert tortoises make very efficient use of any moistures they intake.
Most of their water intake came from the foods they eat, and they have the ability to store water for significant periods. They are very well adapted to life in the desert.
The desert tortoise has a variety of predators. They include coyotes, Gila monsters, ravens, badgers, kit foxes, roadrunners, and fire ants. Eggs and juvenile desert tortoises, whom have a thinner shell are particularly vulnerable. Mojave Desert tortoises also face threats from urbanization, habitat destruction, disease, and invasive plant species. Ravens living near urban areas are particularly destructive to the Mojave Desert tortoise.
Desert tortoises mate in the spring and fall. Female tortoises lay a grouping of 3–5 hard–shelled eggs typically early in the summer. The eggs are the size of ping–pong balls. The eggs hatch by September.
However, since the 1980s, Mojave Desert tortoise populations have significantly declined. Because they are now a threatened species, it is unlawful to touch, harass, harm, or collect wild desert tortoises.
Mojave Desert tortoises now face a new potential threat to their habitat: wind and solar farms. While these renewable sources of energy may be very important to wean the United States off its dependence on foreign oil, they come with a cost. The space and equipment needed to produce these sources of energy, take up important wildlife habitat.
California is the epicenter for proposed solar energy production. There are currently ten large proposed solar energy farms in Mojave Desert tortoise regions. These proposed solar farms had the enthusiastic backing of former California Governor Arnold Schwarzennegger.
There was a big push to get approval on these solar projects in 2010 as Federal stimulus funds, which could contribute up to 30% projects' costs, expired at the end of the 2010 calendar year. The proposed solar farms could only receive federal contribution if construction begins by years end. If all of the proposed solar farms broke ground by the end of 2010, the amount of federal contribution towards their costs would be in the billions of dollars.
There were numerous environmental concerns with the proposed solar farms. Environmentalists are seeking to ensure that the areas proposed for the farms are protected and all projects comply with state and federal environmental laws. However, some people believe that some habitat destruction is worth cost for the economic and energy gains from these projects.
The Ivanpah Solar Farm near Primm, has already been scaled back in its proposed size due to the amount of Mojave Desert tortoise habitat it would eliminate. In light of a government budget crunch and tight time line for federal funds, it will be interesting to see how many of these solar farm projects move forward and at what scale.