The presence of rattlesnakes in Illinois is a common question. While Illinois is home to numerous snake species, only a small number are venomous, and even fewer are rattlesnakes. Understanding which species inhabit the state and where they live can help foster appreciation and safe coexistence with these often misunderstood reptiles.
Rattlesnake Species in Illinois
Illinois hosts two native rattlesnake species: the Timber Rattlesnake (Crotalus horridus) and the Eastern Massasauga (Sistrurus catenatus). Both are venomous pit vipers, characterized by heat-sensing pits between their eyes and nostrils, triangular heads, and vertical pupils.
The Timber Rattlesnake is a large, stout-bodied snake, measuring 36 to 60 inches in length. Its body coloration varies, appearing gray, yellow, or greenish-white, marked with distinct dark bands or chevron-like crossbands along its back. A rust-colored stripe may be present down its back, and adults have a uniformly black tail.
The Eastern Massasauga is smaller, ranging from 18 to 30 inches long, with a grayish-brown body featuring dark, light-edged blotches along its back and sides. Its tail has several dark brown rings. This species is sometimes referred to as the “swamp rattler” due to its preferred habitats.
Where Rattlesnakes Live in Illinois
Rattlesnakes in Illinois occupy specific habitats, reflecting their ecological needs. The Timber Rattlesnake is found in the southern one-third of Illinois, particularly in counties bordering the Mississippi River with forested river bluffs and rocky outcrops. They may also inhabit abandoned sawdust piles and fields during summer. They hibernate in rock crevices, sometimes with other snake species.
The Eastern Massasauga has a scattered distribution in Illinois, found in localized populations in the northern two-thirds of the state. This species prefers wet prairies, bogs, marshy grasslands, and old fields. During summer, they may move to drier adjacent areas like old forests or agricultural lands. Massasaugas utilize crayfish burrows or other underground cavities for shelter and hibernation.
Encountering Rattlesnakes Safely
Encountering a rattlesnake in Illinois is uncommon, but knowing how to react ensures safety. Maintain awareness of your surroundings, especially in areas known to harbor rattlesnakes. Wearing closed-toe shoes or boots and long pants can provide some protection when walking in tall grass or rocky terrain. Stay on designated trails and avoid placing hands or feet into unseen areas like rock crevices or dense brush.
If you encounter a rattlesnake, give it ample space, ideally at least six feet. Rattlesnakes prefer to avoid confrontation and will try to escape or warn you by rattling their tail. Do not attempt to approach, handle, or harass the snake, even if it appears docile or dead. Slowly back away from the snake to create distance, allowing it to move away.
In the rare event of a rattlesnake bite, seek immediate medical attention. Remain calm and keep the bitten limb as still as possible, ideally below the level of the heart. Remove any jewelry or restrictive clothing from the affected area, as swelling may occur. Do not attempt to cut the wound, apply a tourniquet, or try to suck out the venom, as these actions can cause more harm than good.
Protecting Illinois’ Rattlesnakes
Both rattlesnake species in Illinois face conservation challenges, leading to their protected status. The Timber Rattlesnake is listed as a state threatened species, while the Eastern Massasauga is state endangered and federally threatened. These classifications reflect significant declines in their populations.
Habitat loss and fragmentation due to agricultural expansion and urban development are threats to these snakes. Indiscriminate killing by humans, driven by fear or misunderstanding, also contributes to their decline. Protecting these species involves preserving their remaining habitats and educating the public about their ecological importance. Rattlesnakes play a role in their ecosystems by helping to control rodent populations.