They are not easily approached, and will scurry into the nearest crevice at any sign of danger. They then fill their lungs with air becoming almost impossible to dislodge from the crevice. They can also deliver a painful bite. Females, and the young of both sexes have bands across the body and tail. When selecting a chuckwalla, one should procure a young lizard as they adapt better to captivity.
Older males can be especially difficult.
I use olive oil to alleviate this problem. Gravel or sand can be a good substrate, but caution should be used when placing rocks in the cage as chuckwallas are powerful and may displace the rock causing injury to themselves or to cagemates. In captivity, chuckwallas will eat dandelions, kale, endive, collard greens, broccoli, carrots and other nutritious vegetables. Depending on the individual, they may also eat waxworms, jumbo mealworms and grasshoppers. I have one chuck who enjoys anole lizards.