Side-blotched Lizard

Uta stansburiana

The side-blotched lizard is one of the most abundant and commonly observed lizards in the West's drier regions. This lizard is one of the first to appear in the spring and last to hibernate in the late fall.

Identification

Small in size, 4-6 inches long from snout to tip of tail; body length 1.5-2.5 inches (SVL snout to vent length). This lizard is generally brownish, but it may be darker or lighter, and has a dark blotch located on each side of the chest just behind the front leg; hence, the common name. Small whitish spots cover the body.

The scales on the back are small and lack spines, while there are larger scales on the head. The side-blotched lizard has a complete gular fold, which is a fold of skin that covers the back portion of the throat. Males may have some pale blue speckling on their bodies.

Habitat

Dry areas that are sandy or gravelly with rocks and scattered plants. Found in elevations from below sea level to 9,000 feet.

Range

From central Washington south to the tip of Baja, California, on the east side of the Cascades and Sierras. East to western Colorado and west Texas, and into central Mexico.

Life of the Side-Blotched Lizard

This common lizard thrives in the arid regions of the West. Due to its small size, this lizard can heat up quickly; hence, it can be active on warm winter days while other lizards are in deep hibernation. This ability to be active in winter helps the lizard restore fat reserves, which are necessary for surviving the cold periods when the lizard is not active.

Spring is the start of the breeding season. By April, the females may lay their first set of eggs. There may be up to 12 eggs laid; the eggs take 61 days to hatch. The female may lay up to 3 clutches of eggs a season.

Mostly ground dwellers, side-blotched lizards will climb boulders, logs or rock cairns (piles of rocks that are often used as trail markers) for vantage points, basking sites or to express their territoriality. These and other lizards do "push-ups" which can signify territorial or mating behavior. One lizard may chase another from its turf. One study determined the home range sizes for these lizards: males have a .06-acre home range, females have a .02-acre home range and juveniles have a .01-acre home range. In these home ranges, the territories of males often overlap, while those of the females rarely do.

Side-blotched lizards prey on a variety of creatures: ants, ant lion larvae, flies, mosquitoes, damselflies, dragonflies, beetles, bees, aphids, caterpillars, ticks, scorpions and spiders. The lizard tries to sneak up on its intended prey, then quickly dashes after its quarry and catches its prey in its mouth.

These lizards, in turn, are preyed upon by larger lizards, like the collared or leopard lizard, as wells as by snakes and birds.

Only about 10% of the adult population and 20% of the juvenile population will survive each season. The juveniles reach maturity in the fall or early winter and are ready to mate the following season. Their short life expectancy is offset by a high reproduction rate, which enables the population to continue to exist.

-- Text and photos by Damian Fagan

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