Six-Lined Racerunner

Media
Image of a six-lined racerunner lizard
Scientific Name
Aspidoscelis sexlineata
Family
Teiidae (racerunners and whiptails) in the order Squamata (lizards and snakes)
Description

A long, slender, fast-moving lizard of open areas. Ground color is dark brown or black. There are usually six yellow stripes that extend from the head along the back and sides onto the tail. The stripes may be yellow, white, gray, or pale blue. The tail is long, tan, gray, or brown, with slightly spiny scales that are rough to the touch. The head and front part of the body are tinged with blue or green, especially in males. The belly is gray or bluish gray in males and salmon pink to creamy white in females. Racerunners can run across an open area at what seems like lightning speed.

Two subspecies in Missouri: The eastern six-lined racerunner (Aspidoscelis sexlineata sexlineata) is more common in eastern and southeastern sections. The prairie racerunner (A. sexlineata viridis) occurs statewide except for northern and north-central counties; it has 7 stripes instead of 6 and a wash of bright green over the head and front part of the body.

Size
Average total length: 8 inches.
Where To Find
Six-Lined Racerunner Distribution Map
Two subspecies live in Missouri: the six-lined racerunner in the eastern edge of the state, and the prairie racerunner in the rest of the state.
Active from May to mid-September, racerunners live in dry, open sites with loose soil or sand and little vegetation, such as rocky hillsides, glades, along river floodplains, edges of sand or gravel roads, and railroads. They hide under flat rocks and skillfully dig shallow burrows in loose soil. Their tails break off when grasped by a predator, allowing the lizard to escape. They do not hesitate to enter creeks or pools of water to escape. In winter, they burrow on south-facing slopes.
This species eats insects, spiders, scorpions, and other invertebrates.
Life Cycle
Courtship and mating occur from late April to July. Females lay 1–6 eggs in a burrow about 4 inches deep in sand or loose dirt. Unlike Missouri’s skink species, these racerunners do not remain with their eggs. Hatching usually occurs within 60 days, and hatchlings have a pale blue tail and vivid yellow body stripes.
As the only representative of the whiptail family in Missouri, these lizards bring a little taste of the West and the desert Southwest to our state. Glades, one of the preferred habitats of this species, are like miniature rocky deserts, a delight to hikers and part of our rich natural heritage.
Predators of this lizard include other lizards, such as collared lizards, snakes, birds (including roadrunners), and mammals such as skunks, badgers, and armadillos.
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About Reptiles and Amphibians in Missouri
Missouri’s herptiles comprise 43 amphibians and 75 reptiles. Amphibians, including salamanders, toads, and frogs, are vertebrate animals that spend at least part of their life cycle in water. They usually have moist skin, lack scales or claws, and are ectothermal (cold-blooded), so they do not produce their own body heat the way birds and mammals do. Reptiles, including turtles, lizards, and snakes, are also vertebrates, and most are ectothermal, but unlike amphibians, reptiles have dry skin with scales, the ones with legs have claws, and they do not have to live part of their lives in water.