Six-lined Racerunner Aspidoscelis sexlineata - Special Concern

Family: Teiidae

General Description: The Six-lined Racerunner is a slim lizard with a pointed snout, and a tail nearly twice its body length. Adult total lengths range from 6 to 10.5 inches (15.2–26.7 cm). Aptly named, this lizard has six yellowish-green, white, or pale blue stripes running across its back and sides with a brown, black, or olive background body color. An additional subtle brownish stripe occurs down the central back. Ventral coloration in females tends to be white, whereas males are varying shades of blue. Body scales are rough but dull, and ventral scales are flat, squared, and in eight straight rows. Juveniles look similar to adults, but often have a blue tail that fades as they age.

Behavior: This lizard is a diurnal species that is active during the heat of the day and has a diet consisting of a variety of insects, spiders, and other invertebrates. Six-lined Racerunners are high visual and very fast—they can move with speeds up to 18 miles per hour if they feel threatened. Their tail helps with balance while running, and they typically do not drop their tail to distract predators.

Reproduction: Breeding occurs in late spring or early summer. A male will try to attract a female by showing off his colorfully blue chest and chin, and if successful, a clutch of approximately 1–6 eggs can be laid in mid-summer. A subsequent clutch may be laid several weeks later, and typically hatch 6–8 weeks after being laid in a sandy substrate. There is no parental care in this species.

Habitat: Six-lined Racerunners can be found in sunny, open, well-drained, grassy habitats with areas of bare sand or loose sandy soil such as prairies, riverbanks, abandoned fields, or alongside edges of gravel or dirt roads. They prefer low elevations with dry sandy soil.

Species Range: This species occurs throughout much of the southeastern United States from the Atlantic Coast to the Great Plains, Great Plains, and up the Missouri and Illinois river drainages.

South Dakota Range: This species has only been found in south-central South Dakota where the Sandhills extend into South Dakota. Recent observations of this species have occurred at sand dunes along the Missouri River in extreme southeastern South Dakota, though no voucher specimens exist.

South Dakota Status: This species is listed on the South Dakota Natural Heritage Program. Any sightings of this species should be reported to South Dakota Game, Fish and Parks (report observation).

Account written by Jillian K. Farkas and Alexa R. Kruse

Distribution Map
Distribution map of Six-lined Racerunner (Aspidoscelis sexlineata)

County level distribution of this species in South Dakota. Map generated from data collected from voucher specimens and photographic records. See About for additional information.

Photographs
Six-lined Racerunner (Aspidoscelis sexlineata)
Six-lined Racerunner (Aspidoscelis sexlineata)
Six-lined Racerunner (Aspidoscelis sexlineata)
Six-lined Racerunner (Aspidoscelis sexlineata)
Six-lined Racerunner (Aspidoscelis sexlineata)
Six-lined Racerunner (Aspidoscelis sexlineata)