Lizards are found in Illinois, though their presence might be less obvious than other wildlife. While the state’s colder winters might not seem ideal, several species have adapted to and thrive within Illinois’ diverse ecosystems. These reptiles contribute to the state’s biodiversity and natural balance.
Lizard Species Found in Illinois
Illinois is home to several native lizard species, each with unique traits and behaviors. Among the most commonly encountered are the Common Five-lined Skink, the Six-lined Racerunner, and the Slender Glass Lizard. These species represent the diversity of lizard forms, from limbed skinks to legless types.
The Common Five-lined Skink (Plestiodon fasciatus) is a medium-sized lizard, typically five to eight and a half inches long. Juveniles are distinctively dark-bodied with five prominent, light-colored stripes running lengthwise and a vibrant blue tail. This bright blue coloration often fades as they mature; adult males may become uniformly olive or brown, sometimes developing swollen, orange-red jaws during breeding season. These skinks possess smooth, shiny scales and are known for their ability to detach their tails when threatened, a defense mechanism that allows them to escape predators.
The Six-lined Racerunner (Aspidoscelis sexlineata) is a slender lizard that can reach lengths of six to nine and a half inches, with its long tail accounting for a significant portion of its body. This lizard is named for the six light-colored stripes that run along its olive to brown back. Young racerunners also feature a light blue tail. These lizards are exceptionally fast, capable of speeds up to 18 miles per hour, which aids them in both hunting and evading threats.
The Slender Glass Lizard (Ophisaurus attenuatus) is often mistaken for a snake due to its lack of limbs. Averaging 22 to 42 inches in length, it is the longest lizard species found in Illinois. Despite its serpentine form, the slender glass lizard can be distinguished from snakes by its movable eyelids and external ear openings. Its body is typically yellow to brown with six longitudinal stripes, and it possesses a deep, flexible groove along each side. The name “glass lizard” refers to its tail’s propensity to break off easily when handled or attacked, a defense mechanism similar to that of skinks.
Typical Habitats and Distribution
Lizard distribution in Illinois is not uniform, with many species being more prevalent in the southern parts of the state due to favorable climatic conditions. Specific habitat preferences vary considerably among the different species, influencing where they can be found across Illinois. Lizards generally seek environments that offer both suitable basking sites for thermoregulation and ample cover for protection.
Common Five-lined Skinks prefer wooded areas, including dry uplands, floodplains, and hardwood swamps. They are often found around rotting stumps, logs, and rock piles, as well as in disturbed areas like abandoned buildings or around farm structures. These skinks are common in the southern half of Illinois, with some localized populations extending further north. They are terrestrial and forage during the day.
Six-lined Racerunners thrive in open, sunny areas with dry soils and sparse vegetation. Their habitats include sand prairies, hill prairies, rocky outcrops, fields, and floodplains. These agile lizards are commonly found along the Illinois and Mississippi rivers and in the extreme southeastern counties of the state. They are active during the day and often bask on logs, rocks, or other elevated surfaces.
The Slender Glass Lizard inhabits dry grasslands, sand prairies, old fields, and dry, open woodlands. They prefer areas with loose sand and soil, where they can burrow for shelter or to hibernate. While this species can be found statewide in Illinois, it is not abundant anywhere and is seldom encountered. Despite their wide range, they are considered a species in greatest need of conservation in the state.