Six-lined Racerunner
Cnemidophorus sexlineatus

by Jeff LeClere

Status

No status assigned in Minnesota.

Description

The six-lined racerunner is Minnesota's largest lizard reaching a length of 9 1/2 inches (Conant and Collins, 1991). A colorful lizard that will not be as difficult to distinguish as the other two MN species. The scales are rougher than skinks' but small on the dorsum becoming larger and more rectangular on the belly. There is a patch of enlarged scales on both forearms and the scalation on the tail is larger and ridged giving the tail a rougher feeling instead of smooth as in both skinks. In males, the ground color may be green with blue on the head and belly. Females and young are usually brown. Both sexes have six narrow light stripes down the back and sides. The snout is more pointed and the legs are longer than in both skinks.

Subspecies

The subspecies of six-lined racerunner in Minnesota is the prairie racerunner, Cnemidophorus sexlineatus viridis (Oldfield and Moriarty, 1994).

Range

Racerunners are found in a band of six counties bordering the Mississippi River in southeastern Minnesota.

Habitat

Racerunners come from sandy prairie areas, open rocky bluff prairies similar to good milk, ringneck, racer, and rattlesnake habitat.

Habits

Racerunners may wait until May to begin their seasonal activity period. Racerunners bask atop rocks or logs and actively forage for their food. They are diurnal, but they often take refuge under rocks or logs during the hottest parts of the day in mid-summer. They are accomplished burrowers, and racerunners especially, may construct burrows with entrances that form shallow "dugouts" under rocks or similar cover. Breeding occurs in spring. The male grasps the skin of the female's neck during copulation. They are oviparous and the eggs hatch in August. Prairie racerunners lay about a half dozen eggs in shallow burrows in the sand. The female does not stay with the eggs. The young are about 1 1/4 inches at hatching. All of Minnesota's lizards are quick and rely on speed to escape when they are out and about. Prairie racerunners have been clocked at speeds of 18 miles per hour (Vogt, 1981). The warmer they are, the faster they are. During the heat of the day it is nearly impossible to catch a specimen. It is better to wait until early morning or near dark and catch them by flipping rocks or other cover. They can readily detach their tails regenerating a new one, but it is a bit more difficult to induce them to drop their tails than the skinks. These lizards live in small colonies in suitable habitat, usually sandy goat prairies high in the bluffs. Minnesota's lizards hibernate underground in burrows they dig. They usually begin hibernating in September.

Food

All three species of Minnesota's lizards eat small invertebrates such as crickets, grasshoppers, beetles, spiders, caterpillars, which they chase down and eat. They mash their food up with their strong jaws before swallowing it. Prairie racerunners are voracious and may consume larger prey items, especially at higher temperatures.