The range extends from Maryland to southern Florida, north to Wisconsin, east to eastern Wyoming, eastern Colorado, eastern New Mexico, and central Texas, and south to southern Texas and the Gulf Coast (Trauth and McAllister 1996). Ranges into extreme northeast Tamaulipas, Mexico.

Six-lined racerunners occur from Maryland and Rhode Island through Florida, west to approximately southeastern Wyoming and extreme southern Texas, north in the Mississippi-Missouri Valley to Lake Michigan, western central Wisconsin and south-western South Dakota. A very small population exists in Michigan's Tuscola County.

Biogeographic Regions: nearctic (Native )

endemic to a single nation

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Range extends from eastern Wyoming, South Dakota, Minnesota, Wisconsin, Indiana, Kentucky, Virgina, and Maryland south to southern Texas, the Gulf Coast, and southern Floridat (Trauth and McAllister 1996).

Continent: Middle-America North-America
Distribution: USA (Texas, E New Mexico, E Colorado, SE Wyoming, S South Dakota, Nebraska, Kansas, Oklahoma, Missouri, Arkansas, Louisiana, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, Tennessee, W Kentucky, Virginia, Maryland, Illinois, E Iowa, SW Wisconsin, Michigan, SE Minnesota) Mexico (Tamaulipas [HR 30: 109]).  
Type locality: “Carolina”. Restricted to Charleston, South Carolina, by SMITH & TAYLOR 1950.

Length: 30cm (12in). Maximum snout-vent length about 75mm. (3in); tail about 2 times the head-body length, very slender. Color: Six well-defined, narrow, longitudinal, light, pale blue to yellowish lines on body in females and juveniles, all extending from head to base of tail or groin; the stripe nearest the middle on each side begins near the median edge of the parietal; lateral to this another stripe (dorsolateral) begins at posterior corner of eye; and a lateral stripe begins below the eye and passes through the upper edge of the ear. Dimly evident may be another line extending from the lower part of the ear opening to the upper edge of the arm insertion. The sides between these three stripes are usually black: below the lateral stripe is a narrow dark area blending with the light ventral color; and between the median stripes is a broad brownish area. The median light stripes are indistinguishable on the tail, but the dorsolateral ones extend a considerable distance on it; bordering it below is a black stripe in turn borderd by a light stripe which extends upon the otherwise uniformly dark posterior surface of the thigh. The belly is white in life, sometimes tinged with blue in preserved specimens. Adult males have the same dorsal pattern, except that the lateral stripes and the dark areas above them are indistinct, merged with the belly color; and the black between the dorsolateral and median stripes on each side is less intense. Ventrally the entire belly and throat are suffused with pale blue; the limbs and subcaudal surfaces are cream below. This ventral color may become blackish in formalin.

Scalation: Dorsal scales are very small, granular, 76 to 93 from one side to the other at about the middle of the body. Large, flat, quadrangular, belly plates in 8 longitudinal rows; 2 gular folds, the primary (posterior) overlapped anteriorly by enlarged scales. Large head plates. Scales on posterior surface of lower foreleg all small in both sexes, the central ones not, or seldom, more than 3 times as large as adjacent dorsal scales of the arm.

Length: 27 cm

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1981
Locality: Rachal, 8.9 km N of, on U. S. Route 281, Brooks, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1981
Locality: Rachal, 8.9 km N of, on U. S. Route 281, Brooks, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1981
Locality: Rachal, 8.9 km N of, on U. S. Route 281, Brooks, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1981
Locality: Rachal, 8.9 km N of, on U. S. Route 281, Brooks, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1981
Locality: Rachal, 8.9 km N of, on U. S. Route 281, Brooks, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1981
Locality: Rachal, 8.9 km N of, on U. S. Route 281, Brooks, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1983
Locality: Hebbronville, 4.8 km S of, on Ranch Road 1017, Jim Hogg, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1983
Locality: Hebbronville, 4.8 km S of, on Ranch Road 1017, Jim Hogg, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1983
Locality: Hebbronville, 4.8 km S of, on Ranch Road 1017, Jim Hogg, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1983
Locality: Hebbronville, 4.8 km S of, on Ranch Road 1017, Jim Hogg, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1983
Locality: Hebbronville, 4.8 km S of, on Ranch Road 1017, Jim Hogg, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1983
Locality: Hebbronville, 4.8 km S of, on Ranch Road 1017, Jim Hogg, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1983
Locality: Hebbronville, 4.8 km S of, on Ranch Road 1017, Jim Hogg, Texas, United States, North America

Paratype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Preparation: Ethanol
Year Collected: 1983
Locality: Hebbronville, 4.8 km S of, on Ranch Road 1017, Jim Hogg, Texas, United States, North America

Holotype for Aspidoscelis sexlineata stephensae
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Amphibians & Reptiles
Sex/Stage: Male;
Preparation: Ethanol
Year Collected: 1983
Locality: Hebbronville, 4.8 km S of, on Ranch Road 1017, Jim Hogg, Texas, United States, North America

Habitat and Ecology

Systems

• Terrestrial

This lizard lives in relatively dry regions on sandy or other loose soil, in short grass, sparse woods, or areas with scattered, subxerophytic vegetation. Dryness seems more essential than any other factor; a loose porous soil is generally more often frequented than a loamy soil. Dense vegetation, unless low and not of a moisture-retaining type, is avoided. Within these limits a tremendous variety of habitats are utilized. The land may be flat or hilly, the soil rocky or uniformly fine. In the east they reach elevations as great as 1400 feet above sea level; in the west greater altitudes are attained on the high flat plains. However, nowhere do they reach high elevations in mountains.

Terrestrial Biomes: desert or dune ; savanna or grassland

Comments: Six-lined racerunners inhabit grassland, sandhills, sandy or gravelly banks and floodplains of streams, sparsely vegetated rocky areas at the base of mountains, woodland edges and open woods, beach dunes, and similar situations with full or partial sun exposure. They generally take shelter underground or under rocks or other objects on the ground; sometimes they escape threats by submerging in pools of water and may remained submerged by at least a few minutes. Eggs are laid in a nest dug in soft soil or sawdust pile (Mount 1975) or under logs or other sheltering objects (Barbour 1971).

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Food consists primarily of insects but also includes other arthropods and snails. Stomach contents studies show the normal diet includes grasshoppers, crickets, spiders ants, flies, small moths, and moth or butterfly larvae. Soft-bodied insects are preferred, as beetles are not frequently found. Large butterflies, although killed, may not be eaten. Some insects, as ladybird beetles, are distasteful and are ejected promptly upon being taken into the mouth, and the lips are then usually wiped on the ground, the lizard displaying great discomfort. Racerunners are said to be voracious feeders.

Comments: Eats various insects, spiders, and snails (Collins 1982).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: This species is represented by at least several hundred occurrences or subpopulations (e.g., see map in Trauth and McAllister 1996).

>1,000,000 individuals

Comments: Total adult population size is unknown but probably exceeds 1,000,000.

In Kansas, home range size averaged about 800-1,000 sq m, but individuals sometimes roamed outside their normal range and occasionally moved to new areas hundreds of meters away (Fitch 1958).

Comments: Racerunners are active only during warm daylight hours but generally seek shelter during the hottest midday period in summer. Activity occurs May-September in the north and over a somewhat longer period in areas to the south. Those active in late summer and fall are mostly hatchlings. In Georgia and Alabama, juveniles emerge as early as mid-March, adults mid-April to early May (Etheridge 1983).

Average lifespan

Status: captivity: 6 years.

Maximum longevity: 6 years

Mating occurs in spring, probably not over 2 or 3 weeks after emergence from hibernation. A regular courtship pattern is followed. The male, without stimulus from a female, rubs his cloaca on the ground by moving his hips quickly from side to side while moving in a figure eight. At various times he stops to chase others, not distinguishing betwen males and females. He attempts to ride their backs, nipping the skin in the neck region and scraping their backs with his femoral pores. These attentions are accepted by willing females but fought off by males. Finding a receptive female, the male curls the tail under the female until the cloacas are together. He loops his body in a half coil and grasps the posterior part of the the back in his jaws, at the same time that one hemipenis is inserted. Copulation continues some 5 minutes, after which the female moves away. The eggs, 4 to 6 in number, are laid from early June to middle July. About a week after deposition the eggs measure about 17 x 9.5 mm. They are laid 4 to 12 inches below the surface, frequently under some object on the surface such as a log. Racerunners frequently use mole tunnels, making small side tunnels from them in which the eggs are laid. The young hatch in early August.

In most areas, courtship and mating occur in late spring or early summer. Reproductive females deposit 1-3 clutches of 1-6 eggs during May-August; in the north, egg laying does not begin until June. Eggs are laid in nests dug in soft soil or sawdust piles or under logs or other sheltering objects. Eggs hatch in about 2 months, mostly late July (August in the north) to September. Individuals become sexually mature after their second hibernation.

This species is listed as special concern in the state of Michigan, but it is not nationally or globally threatened at this time.

US Federal List: no special status

CITES: no special status

State of Michigan List: special concern

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Intrinsic Vulnerability: Moderately vulnerable

Population

Population Trend

Global Short Term Trend: Relatively stable (=10% change)

Comments: Extent of occurrence, area of occupancy, number of subpopulations, and population size probably are relatively stable or very slowly declining.

Global Long Term Trend: Increase of 10-25% to decline of 30%

Major Threats

Comments: No major threats have been identified. Locally, some populations have declined or disappeared as a result of conversion of habitat to human uses. Historically, much habitat may have been lost with agricultural expansion.

Conservation Actions

Global Protection: Very many (>40) occurrences appropriately protected and managed

Comments: This species occurs in many parks and other protected areas.

These insect predators are of considerable value in the control of pests in various parts of the country. They important as predators of the beet leafhopper in Utah, and in Florida they are significant in the control of celery pests.

Comments: Reeder et al. (2002) examined phylogenetic relationships of the whiptail lizards of the genus Cnemidophorus based on a combined analysis of mitochondrial DNA, morphology, and allozymes. They determined that Cnemidophorus in the traditional sense is paraphyletic and thus in need of nomenclatural revision. Rather than subsume all cnemidophorine species (including Kentropyx) in a single large genus (Ameiva), they proposed a split that placed the North American "Cnemidophorus" clade in the monophyletic genus Aspidoscelis; under this arrangement, South American taxa remain in the genus Cnemidophorus.

See Walker et al. (1990) for information on continuing hybridization between A. sexlineata and A. tesselata in Colorado.