Desert Spiny Lizard, Sceloporus magister
Desert Spiny Lizard, Sceloporus magister. Photograph taken within the greater Palm Springs area of southern California, March 2021. Photograph courtesy of Dr. Tom Bartol, Carlsbad, California. Identification courtesy of Gary Nafis, Californiaherps.com.
The Desert Spiny Lizard, Sceloporus magister, is a member of the Phrynosomatidae family of North American Spiny Lizards, which include the Zebra-Tailed, Earless, Fringe-Toed, Spiny, Tree, Side-Blotched, and Horned Lizards. The Phrynsomatidae family consists of one hundred thirty-six members placed in nine genera. There are one hundred fourteen species in the Sceloporus genus. The Desert Spiny Lizard is known in Mexico as Lagarto Espinoso Del Desierto.
Desert Spiny Lizards are robust and stocky with large, pointed keeled scales. Their color is variable, and is typically light tan, yellowish, or brown dorsally with indistinct dark spots or crossbands. The side of their neck is marked with a large, dark brown to black wedge-shaped mark. Thin dark lines extend caudally from the rear of their eye and mouth. Their shoulders have tan yellow triangular spots. Sexual dimorphism is displayed with males possessing enlarged postanal scales and femoral pores, a swollen tail base, and a bluish patch on their throat and sides of their stomach with black edges. Additionally, males often have a dark purple to black band with light borders down the center of their back. Conversely, females are pale in color ventrally with faint or no blue markings. The head of a female becomes orange or red during the breeding season. Juveniles have smaller dorsal scales with dark and/or pale spots arranged in transverse rows across their dorsum. As they grow, these markings may form blotches. Desert Spiny Lizards grow up to 14 cm (5.5 in) in snout-to-vent length. Their tail is slightly longer than their snout-to-vent length with 10 to 16 (typically 13) femoral pores on each side. Their preferred body temperature is around 35°C (95°F), although they may be active at warmer temperatures.
Desert Spiny Lizards are most active from March or April through October and brumate during the winter months. They are primarily diurnal, but may be active at dusk or night following summer rains. Occasionally, they can be seen basking in the winter. Desert Spiny Lizards are skilled climbers and are commonly seen on rocks, trees, and walls. They shelter under rocks, logs, and other surface objects as well as cracks, burrows, and woodrat nests. They are commonly found on trees, rocks, and on the ground near cover. They are very wary and escape danger by running away quickly into brush, rocks, or burrows. They can detach their tail, which wriggles after becoming detached, to distract a predator and allow the rest of them to escape. Their tail will regenerate, however, the regenerated tail is not the same color or size as the original. Desert Spiny Lizards are primarily sit-and-wait predators, though sometimes they will actively forage. They are prey generalists and will typically consume anything that fits into their mouth, including insect larvae, ants, beetles, grasshoppers, spiders, centipedes, and caterpillars. Occasionally, they will consume hatchlings of lizards and nesting birds, leaves, flowers, and berries. In turn, they are preyed upon by large birds, snakes, and lizards.
The Desert Spiny Lizard reach sexual maturity in two to three years. The males are territorial and frequently perform push-up displays to demonstrate their presence and command of a territory. During these displays, males stand tall, extend their throat to expose their blue coloring, and push their body up and down repeatedly. They breed in spring and early summer, typically in May and June, and females lay a clutch of 3 to 19 eggs between May and August. During favorable years, females may lay more than one clutch. Eggs are deposited in nests constructed in friable, sandy, well-drained soil. The young emerge throughout August into October, and sometimes October. The Desert Spiny Lizard have a life span of five to six years years in the wild.
The Desert Spiny Lizard may be confused with Clark’s Spiny Lizard, Sceloporus clarkii (smaller in size with distinct cross bands on their forelimbs with three elongate scales on the anterior border of their ear that extend backwards over their ear opening).
From a conservation perspective, the Desert Spiny Lizard is currently considered to be of Least Concern due to their relatively large and stable extent of occurrence, area of occupancy, number of subpopulations, and population size. No major threats have been identified for this species.