Illinois is home to four species of venomous snakes: the timber rattlesnake, eastern copperhead, cottonmouth, and eastern massasauga, according to the Illinois Department of Natural Resources and corroborated by multiple sources.
Although a venomous snake bite is rarely fatal to humans, it can cause significant tissue or nerve damage. The Illinois Department of Natural Resources emphasizes the low risk of being bitten, but stresses the importance of knowing how to identify these reptiles and where they are most likely to be found.
The timber rattlesnake, similarly known as the banded or canebrake rattlesnake, is currently listed as an endangered species in Illinois and is legally protected; It’s illegal to kill one. These snakes, reaching lengths of 36 to 60 inches, inhabit deciduous forests, woodlands, and rocky ledges. Their venom contains both neurotoxic and hemotoxic substances, affecting both the nervous system, and tissues. Despite not being inherently aggressive, timber rattlesnakes will bite if threatened, and authorities advise against handling them, even if injured.
Eastern copperheads, common in the lower areas of Illinois, are identifiable by their broad heads, hourglass-shaped patterns, and tan coloration. These snakes, ranging from 20 to 37 inches in length, typically reside in deciduous forests, mixed woodlands, swamps, and rocky areas. They are primarily nocturnal and often lie still, making them sometimes difficult to spot.
The northern cottonmouth, and eastern massasauga are also native to Illinois. The eastern massasauga is endangered in Illinois, living in swamps and marshes. The Illinois Endangered Species Protection Board also lists the Kirtland’s snake, plains hognose snake, and eastern coachwhip as threatened species.
The Illinois Department of Natural Resources notes that habitat alteration and loss, along with over-exploitation for the pet trade, are the chief conservation concerns for Illinois snakes. Misinformation and irrational fears also contribute to declining snake populations.
