Tortoises: Testudinidae

Physical characteristics: This medium-sized tortoise has a tall, dome-shaped upper shell, or carapace, and flat front legs. The carapace can reach up to 19 inches (49 centimeters) in length.

Geographic range: Desert tortoises live in the United States and Mexico.

Habitat: Found in the southwestern United States and northwestern Mexico, this species makes its home in cactus deserts and spots with thorny shrubs.

Diet: The desert tortoise eats mostly plants, including grasses, cacti, and flowers.

The desert tortoise makes its home in cactus deserts and places with thorny shrubs. (©Tim Davis/Photo Researchers, Inc. Reproduced by permission.)

Behavior and reproduction: The desert tortoise is unusual in that it makes burrows into which it crawls to escape attackers and hot, dry weather. In some cases, the burrow is barely big enough for the tortoise to fit inside, but in others, it can be up to 33 feet (10 meters) long. In especially cold weather, the tortoises will crawl to the deepest part of the burrow and enter a deep sleep, called hibernation (high-bur-NAY-shun). When they are active, desert tortoises notice and interact with one another. When two meet each other, they bob their heads back and forth. During mating season, which runs from spring to fall, a male will try to convince a female to pair with him by biting at her legs, bobbing his head at her, and occasionally by ramming into her shell with his. A male frequently will ram shells with other males, too. He often hisses or grunts while mating with a female. The female lays eggs one to three times a year, usually laying five or six eggs at a time, although she may lay as few as two or as many as fifteen. Sometimes, she skips an entire year. The eggs range from 1.6 to 1.8 inches (4.0 to 4.5 centimeters) long and 1.3 to 1.5 inches (34 to 38 centimeters) wide. They hatch in about three to four months.

Desert tortoises and people: People hunt these tortoises for their meat, which is often shipped to Asian food markets located in the western United States.

Conservation status: According to the World Conservation Union (IUCN), the desert tortoise is Vulnerable, which means that it faces a high risk of extinction in the wild. The U.S. Fish and Wildlife Service lists the tortoise as Threatened, or likely to become endangered in the foreseeable future. The danger to the tortoises comes from both loss of their habitat and a dangerous bacterial infection. ∎