Whiptail Lizard (genus Aspidoscelis)

ReptileLizardAmericas

Overview

Whiptail lizards (genus Aspidoscelis) are slim, alert, fast-moving lizards of the Americas, named for their very long, whip-like tails. Usually marked with bold pale stripes (and sometimes spots) running down a slender body, they are restless, twitchy foragers, constantly flicking their tongues and probing the ground as they dash about in warm, open country. They are close relatives of the tropical tegus and the South American whiptails.

Whiptails are biologically famous for a remarkable reason: several species are all-female and reproduce by parthenogenesis — cloning — with no males involved at all. These unisexual species arose from hybridisation between other whiptails, and their populations consist entirely of females that lay fertile eggs producing more females.

Note: “whiptail” covers many species (some sexual, some all-female); details here describe the genus broadly. Treat general statements as approximate and verify against authoritative sources.

Habitat & Range

Whiptails live across the warmer parts of the Americas — from the United States through Mexico and into South America — in open, sunny, often arid habitats such as deserts, grasslands, scrub, dry woodland, and rocky areas. They favour warm ground where they can bask and forage actively, and they shelter in burrows or under cover when inactive.

Diet

Whiptails are carnivores that feed on insects, spiders, and other small invertebrates, including termites, beetles, grasshoppers, and larvae, which they find by actively searching and digging through soil and leaf litter rather than waiting in ambush. Their busy, nose-to-the-ground foraging style suits a diet of abundant small prey.

Behavior

Whiptails are among the most active and fast-moving of lizards, racing across open ground and rarely staying still, foraging energetically and basking to stay warm. The genus's most famous feature is reproduction: in the all-female (parthenogenetic) species, every individual is female and produces clones of itself without mating. Intriguingly, even these all-female whiptails sometimes perform mock-mating behaviour with one another, which can help stimulate egg-laying. Sexual whiptail species, by contrast, have both males and females and reproduce normally. Like many lizards, whiptails can shed the tail to escape a predator and regrow it.

Human Interaction & Conservation

Whiptails are harmless, fascinating lizards, and the all-female cloning species in particular are a celebrated subject in biology for what they reveal about reproduction and evolution. Most whiptails are common and adaptable, though some restricted-range species can be affected by habitat loss. They are beneficial as insect-eaters and pose no threat to people. Consult authoritative sources for species-specific status.

More photos of the whiptail lizard