Iguanidae , the iguana family.
The Sonoran Desert and Mojave Desert of southwestern North America.
Sandfields, washes or creosote flats in desert.
These are the “big white lizards” that may be seen racing across roads on hot summer days.
Heavy bodied lizards with blunt heads, they are sandy-colored with darker spots and bars and their color changes from dark in the cool morning to very white at midday. Their scales are smooth, fine and granular and the raised crest, so prominent in tropical iguanas, barely even forms a small ridge.
Primarily herbivorous, they eat leaves, buds, flowers and occasionally insects, carrion and their own fecal matter (for undigested nutrients and vitamins). They are often seen balancing high in creosote bushes eating the flowers.
They are preyed on by roadrunners, coyotes, snakes and hawks. They have the ability to lose their tails to predators and regenerate a new tail (often with a different pattern and color).
Courtship behavior includes “Push-ups” which are also thought to proclaim territory to other males and intruders and the breeding season is in April and early May. Eggs are laid in sand.
They are active on hot days long after other lizards have retreated into the shade. Their normal body temperature is 105F and temperatures as high as 115F have been recorded. They dig their own burrows where they hibernate with the onset of cool temperatures from October to March.