Habitat
Their preferred habitat is largely contained within the range of the creosote bush, mainly dry, sandy desert scrubland below 3,300 ft (1,000 m). It can also be found in rocky streambeds up to 3300 ft.

These lizards can withstand high temperatures and are out and about after other lizards have retreated into their burrows. They burrow extensively, and will often climb into shrubs for shelter and defense. Their burrows are usually constructed in the mounds of sand that accumulate around the bases of bushes like the creosote. They also often use ready-made burrows of Kit Foxes and Desert Tortoises.

Description
The desert iguana is a blunt, medium-sized lizard which grows to 16 in (41 cm) including the tail. They are pale gray-tan to cream in color with a light brown reticulated pattern on their backs and sides. Down the center of the back is a row of slightly-enlarged, keeled dorsal scales that become slightly larger as you move down the back. The reticulated pattern gives way to brown spots near the back legs, turning into stripes along the tail. The tail is usually around 1 1/2 times longer than the body from snout to vent. The belly is pale. During the breeding season, the sides become pinkish in both sexes.

Comments
Diet and reproduction
Mating takes place in the early spring. It is believed that only one clutch of eggs is laid each year, with each clutch having 3-8 eggs. The hatchlings emerge around September.

Desert iguanas are primarily herbivorous, eating buds, fruits and leaves of many annual and perennial. They are especially attracted to the yellow flowers of the creosote bush. They have also been reported to eat insects, feces (mammal and lizard) and carrion.

Predators of these iguanas and their eggs are birds of prey, foxes, rats, Long tailed Weasels, some snakes and humans.

Taxonomy
The species was first described in the Catalog of North American Reptiles, by Spencer Fullerton Baird and Charles Frédéric Girard, in 1859 as Crotaphytus dorsalis it was reclassified two years later as Dipsosaurus dofus dorsalis by Edward Hallowell. The generic name comes from a combination of two Greek words meaning "thirsty lizard": "Dipsa" (δίψα) for "thirsty", and "sauros" (σαῦρος) for "lizard". The specific name, "dorsalis", comes from the Latin word dorsum meaning "spike", in reference to a row of enlarged keeled scales on the middle of the lizard's back which form a crest that extends almost to the tip of its vent. Dipsosaurus contains two species, D. dorsalis, and D. catalinensis.

Source
Wikipedia
http://en.wikipedia.org/wiki/Desert_iguana