Plants and Animals
Aspidoscelis sexlineata Six-lined racerunner
The Six-lined Racerunner is a slim lizard with a very long tail (about twice its body length) and a pointed snout. It is black, gray, brown or olive in color with six yellowish green, white, pale blue, or gray stripes running down the back and sides with an often indistinct brownish stripe down the middle of the back. In adults, especially males, the neck and front part of the body may be green or blue-green. The belly is generally white, but in males, it is blue. Adult total lengths range from 6 to 10.5 in (15-27 cm), with maximum body or snout-vent length of 3.4 in (8.6 cm).
Status and Rank
US Status: No Status/Not Listed
State Status: T - Threatened (legally protected)
Global Rank: G5 - Secure
State Rank: S1 - Critically imperiled
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Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.
The Six-lined Racerunner is known from only one population in east-central Michigan. This site can be characterized as dry, bare, rocky, old field habitat along a roadside which is likely the result of disturbance associated with construction of the road and not a natural community. The surrounding habitat is mesic northern forest. This population is disjunct from the rest of the species' range which is located primarily south and west of Michigan. In other parts of the species’ range, Six-lined Racerunners typically occur in sunny, open, well-drained, grassy habitats with areas of bare sand or loose sandy soil such as prairies, oak savannas, riverbanks, abandoned fields, vacant lots and road cuts.
Natural Community Types
For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.
Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.
Although it is still unclear whether the one known population of Six-lined Racerunners in Michigan is a natural or introduced population, it should be protected and maintained until this can be determined with further research. Natural succession or management activities that result in increased shade or increased ground cover could pose a serious threat to this species. The open, sparsely vegetated habitat at the known site should be maintained. Management activities should occur during times of the year when the lizards are inactive or less active (e.g., Oct-Apr) to minimize the potential for adverse impacts to the species. Pesticide use which could reduce insect prey abundance should be limited or avoided.
Active from first week of May to fourth week of August
Breeding from first week of May to second week of June
Nesting from first week of June to third week of July
Six-lined Racerunners have a fairly short activity season and are rarely observed between mid-August and late May. The best way to survey for this species to visually search for this species on the surface and under cover in suitable habitat on warm, sunny days from late May to mid-August. At night or on cool, cloudy days, Six-lined Racerunners remain in burrows or under cover (e.g., woody debris, leaf litter, rocks).
Visual encounter surveys
Survey Period: From fourth week of May to third week of August
Time of Day: Daytime
Cloud Cover: Clear
Air Temperature: Warm
- Karns, D.R. 1986. Field Herpetology: Methods for the Study of Amphibians and Reptiles in Minnesota. Occ. Pap. No. 18. J.F. Bell Museum of Natural History, University of Minnesota, Minneapolis.
- Harding, J.H. 1997.Amphibians and Reptiles of the Great Lakes Region. The University of Michigan Press, Ann Arbor. 378pp.
- Harding, J.H. and J.A. Holman. 1990. Michigan Turtles and Lizards. East Lansing Cooperative Extension Service, Michigan State University Bulletin E-2234. 94pp.