According to Saguaro National Park, the diet of a Desert Spiny Lizard is insects, spiders, centipedes, lizards, and occasional plant material. So I guess they are part-time cannibals! Yikes!
At least they are not venomous. Only two lizards in the world are venomous – the Gila monster (which we also have in Tucson) and the beaded lizard, which lives farther south in southern Sonora and tropical deciduous forests even farther south.
Spiny lizards are metachromatic, which means they change their color based on temperature. Colors are much darker in colder conditions than in hot. The females, as pictured above, develop red or orange heads during the breeding season. Note how beautifully the colors on this one blends into its environment.
Image copyrighted. Any use requires licensing from Martha Lochert.