The Teiidae family of lizards represents whiptail lizards. In Colorado, five species of Teiidae lizards exist: the six-lined racerunner (Cnemidophorus sexlineatus), western whiptail (Cnemidophorus tigris), plateau striped whiptail (Cnemidophorus velox), triploid checkered whiptail (Cnemidophorus neotesselatus) and diploid checkered whiptail (Cnemidophorus tesselatus). These lizards are medium-sized with long, whip-like tails as their names suggest. Whiptails dine on insects and arachnids. This Colorado family of reptiles are diurnal, meaning they are active during the day and sleep at night. The six-lined racerunner has six lines running down the length of its body, while triploid and diploid checkered whiptails have checker patterns on their skin.
The largest number of lizard species in Colorado belong to the Phrynosomatidae family of reptiles. All of Colorado's Phrynosomatidae lizards live in southern regions of the state, which feature desert and grassland habitats. Three of Colorado's Phrynosomatidae species are horned lizards: round-tail horned (Phrynosoma modestum), short-horned (Phrynosoma hernandesi) and Texas horned lizards (Phrynosoma cornutum); these lizards are in the Phrynosoma genus. The Phrynosomatidae family also covers three spiny lizards in Colorado: desert spiny (Sceloporus magister), sagebrush (Sceloporus graciosus) and prairie lizards (Sceloporus undulatus). The tree (Urosaurus ornatus), lesser earless (Holbrookia maculata) and side-bloched (Uta stansburiana) lizards round out the list of Colorado's Phrynosomatidae reptile species.
Colorado is home to three skink lizards -- Great Plains (Eumeces obsoletus), variable (Eumeces gaigeae) and many-lined (Eumeces multivirgatus) -- which are in the Scincidae reptile family. Skinks have smaller legs and more pronounced necks than other lizard species. These reptiles also slither similarly to snakes. Skinks have the ability to regenerate their tails. Tail regeneration helps skinks evade predators; if predators reach for their tails, the tail will rip off and allow skinks to make a quick escape. The Great Plains skink is the largest of Colorado's three skinks; as adults, they grow up to 5 inches.
Two Crotaphytidae family lizards live in Colorado: longnose leopard lizard (Gambelia wislizenii) and common collared lizard (Crotaphytus collaris). Crotaphytidae lizards do not have external spines or ridges on their head. These lizards also do not possess any scales covering their ears. Long tails and limbs are physical characteristics of the longnose leopard and collared lizards. The collared lizard is one of the fastest lizards in Colorado. These reptiles run to speeds of 16 mph. When running, collared lizards raise their head and front legs; the lizards run at a 45-degree angle. Female longnose leopard lizards are longer than males.