Several species of chuckwallas occur in the Sonoran and Mojave deserts. The most plentiful are the Common chuckwalla (Sauromalus ater) and the Western chuckwalla (Sauromalus ater obesus). Adults males get up to 16 inches long. The Isla San Esteban chuckwalla (Sauromalus varius), also called the piebald chuckwalla, inhabits several islands in the Gulf of California. This species can get up to 24 inches long. A population of Isla San Esteban chuckwallas also occurs at the Arizona-Sonora Desert Museum (ASDM) as part of a research and education project.
All chuckwallas are large, heavy-bodied lizards with folds of skin along the neck, shoulders and sometimes along the sides. The head of males tends to be black with lighter colors along the body. Females are generally lighter-colored shades of gray. Color varies with species, sex, and age.
Chuckwallas are found in rocky areas within desert scrub and woodlands. They use the rocks for basking, shelter, and protection from predators. For protection, a chuckwalla will seek a rock crevasse and wedge itself in by inflating its body with air. The top photo shows this behavior.
Males will fight over territory and females. Dominance for both males and females is often based on size. Males will warn rivals with “push-ups”, bobbing the head, and mouth gaping. These lizards are not harmful to humans. In fact, the Seri Indians and other Native American peoples collected and raised the lizards for food.
Chuckwallas are mainly herbivores that eat a variety of vegetation including fruit, leaves, buds, and flowers of many plants. They also eat insects.
Chuckwallas breed from April through August. Females lay eggs in clutches of five to 16. The eggs are incubated for 33 to 50 days. Juveniles (and females) are usually banded. The lizards reach sexual maturity in two to three years.
Chuckwalla predators include hawks, American kestrels, coyotes, Mohave rattlesnakes, and humans.
See more photos of three species from the Arizona-Sonora Desert Museum digital library here.
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