Clark's Spiny Lizard
Sceloporus clarki

Clark’s Spiny Lizard inhabits central to southeastern Arizona and southwestern New Mexico, extending southward through western Mexico into northern Jalisco. In Arizona, its distribution reaches as far west as the Ajo and Puerto Blanco Mountains and as far north as Mohave County. It can be found from near sea level up to elevations around 6,000 feet (1,830 meters). Notably, it is also present on offshore islands such as Tiburón and San Pedro Nolasco in the Gulf of California. This species occupies a range of habitats associated with mountainous and upland terrain. It thrives in oak-pine woodlands, tropical deciduous forests, subtropical thornscrub, and several woodland types including Madrean Evergreen and Great Basin Conifer Woodlands. It often resides along riparian corridors and among rocky outcrops or piles. Compared to its close relatives, Clark's Spiny Lizard shows a preference for slightly more humid and higher elevation environments. Diurnal and notably wary, Clark’s Spiny Lizard is most often observed on tree trunks or large branches where it basks in the sun. If disturbed, it instinctively darts to the opposite side of a trunk or rock to avoid detection. Its alert and skittish behavior makes it a challenge to observe or photograph. This species may also shelter under rocks or within crevices, particularly during cooler periods. It enters hibernation during the colder months of late fall and winter. An opportunistic feeder, Clark’s Spiny Lizard consumes a wide variety of arthropods, including beetles, ants, wasps, caterpillars, grasshoppers, and spiders. It also supplements its diet with occasional plant matter, such as buds, leaves, or flowers. This dietary flexibility supports its survival across varied ecological zones. Breeding begins in the spring, with egg-laying typically occurring from late May through July. Females lay clutches containing anywhere from 4 to 28 eggs, depending on environmental conditions and individual health. In favorable years, a second, smaller clutch may be laid in mid to late summer, typically July or August. Clark’s Spiny Lizard can be easily confused with other members of the Sceloporus genus, but careful observation reveals key differences. For instance, unlike Yarrow’s Spiny Lizard, it lacks a complete collar, and it differs from the Desert Spiny Lizard by having distinct forelimb banding and fewer ear scales. Its tendency to hide quickly behind tree trunks or rocks adds to its elusive nature, often requiring stealth or teamwork to study or photograph effectively in the wild. Desert Spiny Lizards are found in a variety of habitats, including Sonoran and Great Basin Desertscrub, chaparral, grasslands, and juniper woodlands. They are often encountered on rocky slopes, bajadas, plains, and low valleys. They readily use trees, rock piles, wood piles, and packrat nests as perches and refuges, showcasing their adaptability. These diurnal lizards are active baskers, frequently seen on rocks, branches, or other sunlit surfaces. When startled, they retreat to cover, such as rock crevices, tree trunks, or burrows. Known for their strong jaws, they may bite when handled. In cooler months, they enter hibernation. The Desert Spiny Lizard has an opportunistic diet, feeding primarily on insects like ants, beetles, and grasshoppers, along with spiders, centipedes, and even smaller lizards. They occasionally consume plant material, such as buds, flowers, and berries. Reproduction occurs in spring and summer, with females laying one or two clutches of eggs each season. Clutch sizes range from 3 to 19 eggs, depending on the female’s size and environmental conditions. Hatchlings emerge from late May to July, with juveniles developing quickly in the warm desert environment. Several similar species can be confused with the Desert Spiny Lizard, including Clark’s Spiny Lizard (Sceloporus clarkii), Granite Spiny Lizard (Sceloporus orcutti), and Yarrow’s Spiny Lizard (Sceloporus jarrovii). The black wedge-shaped shoulder marking and regional coloration help differentiate S. magister from these species. Despite ongoing taxonomic debates, the Desert Spiny Lizard remains recognized as a single species with notable regional variation in its appearance.