Reptiles
Six-Lined Racerunner
Aspidoscelis sexlineata · also called six-lined racerunners
A six-lined racerunner rarely stays still long enough to be studied closely, darting between patches of cover with six pale stripes flashing against a dark, streamlined body. Both the name and the reputation are earned honestly: this is one of the fastest lizards found anywhere in North America.
Overview
The six-lined racerunner, Aspidoscelis sexlineata, is a fast, striped lizard native to open grassland and sandy habitat across the eastern and central United States. Its speed and near-constant motion make it genuinely difficult for predators to approach.
Speed as the whole strategy
Rather than relying on camouflage or ambush, the six-lined racerunner leans almost entirely on raw speed and restlessness, a lizard that treats staying in one place for too long as a risk not worth taking.
Status
Least Concern — widespread and stable across suitable open habitat throughout the eastern and central United States.
Six-Lined Racerunner: common questions
How fast can a six-lined racerunner actually move?
A six-lined racerunner is capable of remarkably fast bursts of speed relative to its size, making it one of the quicker lizard species found in North America, a trait so central to the species' identity that it directly inspired the common name applied to it.
Why does the six-lined racerunner have that specific name?
The six-lined racerunner is named for the six pale, well-defined stripes running the length of its dark body, a bold and fairly distinctive pattern that, combined with the species' notable speed, gives the lizard both halves of its descriptive common name.
Is the six-lined racerunner related to species that reproduce without males?
Yes, the six-lined racerunner belongs to the broader whiptail lizard family, which includes several related species and populations documented to reproduce through parthenogenesis, in which females produce offspring without mating, though this specific reproductive strategy is more prominently associated with certain other whiptail species rather than being a defining trait of the six-lined racerunner itself.
Where does the six-lined racerunner live?
The six-lined racerunner is native to open grassland, sandy areas, and forest edge habitat across much of the eastern and central United States, generally favouring sunny, well-drained terrain with sparse ground cover that suits its fast, active foraging lifestyle.