Desert spiny lizard
Zebra-tailed lizard
Common chuckwalla
Gerry Tietje
One of the first things Claire and I noticed when we moved to SaddleBrooke Ranch (SBR) in June 2021 was how many lizards were around—in our backyard, on the Nature Trail, and in nearby state parks. With my penchant to know more about things in nature, I began to identify and study them. Lizards have elongated bodies with relatively short legs and long tails that taper to the end. They are reptiles, and as such, have no internal thermostats to regulate body temperature, like mammals do. The scientific term for this phenomenon is ectothermic, but most people use the term cold-blooded. The result is that lizards are slow and sluggish when their environment is cold and more active when their environment is warm. Lizards often sunbathe on a rock on a cold morning to raise their body temperatures. There are more than 60 species of lizards in Arizona, and many are found in our area. Three of the more interesting ones are the desert spiny lizard, the zebra-tailed lizard, and the common chuckwalla.
A few days after we arrived in our new home, I was looking at the edge of the arroyo in our backyard and saw a lizard on a rock. It was maybe 5 inches long, had a dewlap (a flap of skin on the throat of a lizard) with blue at its base, and a blue underbelly. It had a wedge-shaped black mark on the side of its neck and was covered with triangular scales, features descriptive of a male desert spiny lizard (Sceloporus magister). This species turns a darker color in winter so that its skin can absorb more radiant heat from the sun. Desert spiny lizards eat insects and other arthropods.
Zebra-tailed lizards (Callisaurus draconoides) are commonly seen on the SBR Nature Trail. They are relatively small, 2.5 to 4 inches in length, and gray to sandy brown with dark spots down their backs. Zebra-tailed lizards have a banded tail, which gave rise to their common name. When stopped, they comically wag their tails from side-to-side, and when threatened, run swiftly with their tails curled up over their bodies. Zebra-tailed lizards can even run short distances on their hind legs! Their diet includes moths, ants, bees, and spiders.
Common chuckwallas (Sauromalus ater) are large, wide-bodied, desert-dwelling lizards in the iguana family. They grow up to 20 inches long and have thick tails that taper to a blunt tip. I saw my first common chuckwalla some years ago at Fossil Falls in Inyo County, Calif. It was basking in the sun on a rock outcropping, its leathery skin folded over portions of its body. When threatened, chuckwallas are known to crawl into a crevice and inflate their lungs like a puffer fish, making it difficult for a predator to dislodge them. Chuckwallas are primarily herbivores, eating flowers, fruit, leaves, and cacti. A good place to see them is the Arizona-Sonora Desert Museum.
Lizards are a valuable addition to our desert environment, especially during the monsoon season, when they consume many insects. Be kind to our lizards!