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NATURAL HISTORY

MOJAVE FRINGE-TOED LIZARD } Uma scoparia
FAMILY: Phrynosomatidae

DESCRIPTION: The Mojave fringe-toed lizard is a flat-bodied lizard with smooth, sand-colored skin featuring a pattern of small black spots. Distinguishing characteristics are found on the lizard’s pale underside with up to three crescent-shaped throat markings, black blotches on each side of the belly, and dark bands across the tail. During breeding season, the lizards develop a yellowish-green tint on their abdomens with their sides turning a pink color. They grow to be up to seven inches long and possess a small head, pointed snout, and a tail equal to the body in length. Large, triangular-shaped fringes on their rear toes are used for speed and mobility in the sand.

HABITAT: Mojave fringe-toed lizards are restricted to areas containing fine wind-blown sand dunes, the margins of dry lakebeds, desert washes, and hillsides. Their habitat ranges from sea level to 3,000 feet in elevation.

RANGE: Mojave fringe-toed lizards are native to the deserts of southern California, as well as a small area of western Arizona. Along the Amargosa River, the Mojave fringe-toed lizard occurs at the Dumont and Ibex dunes and Coyote Holes north of Baker, California.

MIGRATION: This species does not migrate.

BREEDING: Reaching sexual maturity during its second year, the Mojave fringe-toed lizard’s breeding capacity varies annually and is closely linked with seasonal rainfall. After mating in late spring, females lay a clutch of one to five eggs between May and July. Hatchlings appear in September.

LIFE CYCLE: Adults hibernate from November to February by burying themselves up to 12 inches deep in sand. Juveniles are often found closer to the surface and may even remain active all year.

FEEDING: The Mojave fringe-toed lizard feeds on small invertebrates that dwell close to the sand’s surface, such as ants, beetles, grasshoppers, and scorpions. They also eat seeds, leaves, grasses, and flowers. Annual plant species are an important food source during the spring, but reliance on plants diminishes during the summer with increased insect availability.

THREATS: Lying camouflaged just below the sand’s surface, Mojave fringe-toed lizards are crushed by recreational off-road vehicles, which also damage aboveground vegetation that the lizards depend on for food and protection. Habitat loss from urban development and agriculture, toxins from nearby military operations, air pollution, global warming, non-native invasive plant species, and pesticides pose additional threats.

POPULATION TREND: Off-road vehicle traffic has more than tripled at California’s Dumont Dunes since 1999, leaving the Amargosa River population in serious peril. More than 130,000 off-road riders visited the dunes in 2006, further precipitating sharp declines in the number of Mojave fringe-toed lizards.

Photo © William Flaxington