Common Chuckwalla

The Second-Largest Lizard in Utah

Averaging 10 to 12 inches long and built heavy through the body, the chuckwalla is second only to the Gila monster among Utah's lizards - and unlike the Gila monster, it's harmless and strictly vegetarian, browsing on leaves, flowers, and fruit from desert shrubs. Loose folds of skin along the neck and sides give it a baggy, almost comical look, but that skin has a purpose.

When threatened, a chuckwalla doesn't run far. It wedges itself into a rock crevice and gulps air, inflating its body until it's jammed too tight for a predator - or a person - to pull it out. It's one of the more effective defenses in the reptile world, and it's the reason chuckwallas are so tied to rocky terrain with plenty of crevices.

Where & When to Find One

Chuckwallas are a lower-elevation specialist, found on rocky slopes and boulder fields in Zion's Mojave-influenced desert terrain below about 4,000 feet - the same hot, low country where collared lizards and roadrunners turn up. Look for them basking on sun-exposed boulders near cover they can retreat into.

Active in the warmer months, chuckwallas bask conspicuously on rocks in the morning before the heat peaks, then retreat to shade or crevices through the hottest part of the day. Spring, when desert shrubs are flowering, is prime viewing season.

Watching Without Disturbing

If you spot one basking, stay back and move slowly - a startled chuckwalla will wedge itself into the nearest crack, and once inflated it won't come back out while you're nearby. Never attempt to pull one from a crevice; it's stressful for the animal and can injure it. A patient, quiet approach is far more likely to earn you a good look.