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The Lively, Pervasive Side-blotched Lizard

by Patricia Hefre
Georgia Herpetological Society

The side-blotched lizard gets it's common name from the charcoal mark behind the front leg on either side of the lizard. The generic name comes from Captain Howard Stansbury, the first man to survey the Great Salt Lake. Color variations range from glossy hues of tan to darker brown, with specks of blue among the spine. The protective sheen of this lizard is created by a series of fine scales, overlapped like Spanish roofing tiles, covering the body. The side-blotched lizard also demonstrates sexual differences, with the females having beige stripes, spots or chevrons, instead of the blue specks characteristic of the males.

Of particular interest is the parietal or third eye of the side-blotched lizard. Located at the center-top of its head, this physiological adaptation enables the reptile to rapidly adjust its use of sunlight, as well as regulate activity cycles and reproduction. Not a true eye, the parietal has no actual vision properties; still it does possess the major structures equated with standard eyes, such as an iris, pupil, and even a corneal covering. The parietal is actually a photoreceptor that was once thought to be a nonfunctioning leftover from some reptilian ancestry. However, research by Dr Robert Stebbins revealed that the parietal has a istinctive purpose in that its removal leads to disruptions in reproductive cycles and circadian rhythms.

Another interesting aspect of this lizard's physiology is its ability to take advantage of seasonal habitat other lizards cannot utilize. The darker color and small size of this lizard enables it to absorb solar radiation rapidly. Once it has reached its preferred body temperature, 99°F, it changes to a lighter color that reflects the heat. In this way, the side-blotched lizard is able to maintain a satisfactory body temperature during both the summer and the winter.

As desert island lizards, keep the tank warm between 75-100°F (24-38°C). A 10-12 hour photoperiod is best. There is a great need for UV lighting in these desert creatures. An outdoor enclosure and/or natural sunlight is best whenever possible.

Hiding places should be located in both warm and cool spots. Ensure rocks sit securely on the bottom of the tank to keep them from falling on climbing or digging lizards. Ensure humidity levels are low above ground, yet slightly damp in hiding areas.

In the wild, the diet of this agile reptile consists mainly of small insects including mites, ticks, sowbugs, black ants (they avoid red harvester ants), and, surprisingly, an occasional scorpion or two. In captivity, feed side-blotches a variety of small insects including, crickets, waxworms, grasshoppers, beetles and beetle larvae, caterpillars, leafhoppers, spiders, moths, flies, and other flying insects. Make sure insects are free of pesticides. Water is obtained from food. Provide multivitamin and calcium supplementation two to three times weekly. Breeding females need daily supplementation to ensure proper egg development. Juveniles also need daily supplements for proper growth and bone development.

While its diet reflects the side-blotched lizard's spryness, this reptile often falls prey to a variety of enemies, namely snakes, hawks. and roadrunners. Out of necessity, side-blotched lizards are prolific breeders and need little encouragement to breed in captivity beyond a two to three month hibernation period When spring arrives, the side-blotched lizard begins the quest for a mate. Just prior to mating season, males stake out and begin to actively defend territories. By perching himself on a large rock, the male can continually survey his territory while making his presence known to would-be mates and male intruders. If another male ventures into his territory, the male side-blotched lizard warns the intruder by displaying himself through head bobbing and by strutting around. If the warning does not work, the resident male will attack and bite the trespasser. Attacks only last a few seconds and the majority of times the defending male is triumphant.

After mating, the female side-blotched lizard lays from 2-6 eggs in the sand, yet she also reserves sperm in her oviduct for a second clutch two or three months later. Incubate eggs at 82-84°F (28-28°C) Since less than 10% of hatchlings reach adulthood in the wild, and the average adult life-span is a mere five months, conspicuous fertility plays an important role in ensuring survival of this species.