While hiking the Las Vegas Area, it’s easy to give your attention to the lizards scurrying across the desert floor, but by looking up, you may find another intriguing desert dweller quietly perched high in the rocks.
Unlike most other lizards here in the southwest, the Chuckwalla is strictly a rock dweller and is found in rocky outcrops, lava flows, and rocky hillsides of the Great Basin, Mohave and Sonoran deserts.
This is a large, bulky lizard reaching nearly 16 inches long, with folds of loose skin on the sides of its body. Its original species name, obesus, refers to how fat the reptile looks.
Males tend to be slightly larger than females and are often darker in color. Their color varies considerably by region, but generally includes grey, reddish brown and/or yellow. The banded patterns found on juveniles are often retained into adulthood by females.
These day-active lizards emerge in the morning and before seeking food, bask in the sun until reaching an optimum body temperature of 100-105 degrees F. I often see them out and about when it is too hot for other lizards.
The Chuckwalla is primarily a vegetarian and eats fruit, leaves, buds and flowers from a variety of annual as well as perennial plants. It also occasionally supplements its diet with insects. Its favorite foods are yellow flowers and the fruit of the prickly pear cactus.
When the Chuckwalla senses danger, it scurries between rocks and lodges itself tightly into a crevice. Then it inflates itself with air until it becomes securely wedged. This makes it nearly impossible to extract from its retreat.
This is one of the largest lizards native to the United States. It’s a “classic” desert reptile that I always enjoy seeing in the wild.