Desert iguanas, Dipsosaurus dorsalis, are medium-sized lizards that make their home in the hot, dry wilderness of the southwestern United States and parts of Mexico. The reptile has a rounded head, short legs, large ear openings, and a disproportionately long tale. Known for its ability to tolerate heat, a desert iguana can generate a short burst of impressive speed when alarmed.
Generally, desert iguanas grow to an average length of 10 to 16 inches (about 25 to 40 cm). Their backs are covered with brown and gray speckles that thin out near the tail, which is pale with ringed brown bands. A raised set of scales runs down the length of the spine, and the underside is white. During mating season, the males and females both develop a pink discoloration on the sides of their bodies.
These animals are primarily vegetarian, living on the leaves and flowers of several desert plants, especially the creosote bush. They have shown a surprising level of agility compared to other types of iguanas, and will occasionally climb into the upper sections of a bush in search of better flowers. Desert iguanas sometimes eat insects and carrion, as well as their own feces, which is thought to help them maintain important digestive bacteria. Some scientists believe that insects are a bigger part of the diet when the desert iguana is a juvenile.
Because of its impressive heat tolerance, the desert iguana is more active during the hottest parts of the day than are other desert lizards. They do spend a significant part of their life underground — sometimes for safety and sometimes to avoid intense heat. When temperatures surpass 115° Fahrenheit (about 46° Celsius), they have no choice but to take cover.
They usually dig their own burrows but will also modify abandoned mammal nests when there is an opportunity. The tunnels can be quite simple with a single chamber, or they can be more complex with multiple exits. These creatures are shy and are quick to hide when they sense danger. Sometimes they will cover the entrances to their tunnels with sand, thereby making it harder for predators to detect them.
The desert iguana goes into hibernation when the weather cools in the fall and reemerges in March. Breeding season begins shortly after the end of hibernation. They produce one clutch of eggs each year, with about eight eggs maximum. There is some evidence that males and females form pair bonds, at least temporarily.
These animals are sometimes kept as pets. They do better in a larger iguana tank, and some people who live in the right kind of climate set up outdoor enclosures. Whatever kind of environment is chosen, it usually is a good idea to supply the animal with a cave and plenty of rocks. Owners usually need to maintain a fastidiously clean environment, and because this is a desert species, it can be important to avoid excess humidity. Temperature can be controlled with heat lamps as long as shady areas are provided so that the iguana can control its body heat.