Six-lined Racerunner

The six-lined racerunner (Aspidoscelis sexlineata) is a fast, slender, striped lizard of the central and southeastern United States. It is a member of the whiptail lizards, a genus that includes some species consisting only of females.

🧬 Field Guide Specimen: Open Six-lined Racerunner in the CRV Science Field Guide to log the specimen, see its place among the Reptilia lineages in the Cladogram Explorer, and test your recall in the Red List conservation game.

Racerunners dart across open, sunny ground in the day, running at speeds of tens of kilometers per hour, and must warm up before they can move fast. They forage actively for insects and spiders.

Several whiptail species, such as the New Mexico whiptail, reproduce by parthenogenesis, and all individuals are females that clone themselves. They arose by hybridization between two sexual species. Females still perform courtship-like behavior with each other that stimulates ovulation. See Genetics.

The racerunner itself reproduces sexually, with males and females. It is common in prairies, sandhills and open woodlands.

• Genetics — hybrid origins of clonal species
• Green Iguana — another lizard