Wisconsin is home to a diverse array of wildlife, including various snake species. While the term “poisonous” is often used, the correct term for animals that inject toxins through a bite is “venomous.” Wisconsin does indeed have venomous snakes, though they are not widespread and encounters are relatively uncommon. Understanding these species and how to react responsibly is important for safely enjoying Wisconsin’s natural spaces.
The Rare Truth: Venomous Snakes in Wisconsin
Wisconsin is home to only two species of venomous snakes: the Timber Rattlesnake (Crotalus horridus) and the Eastern Massasauga (Sistrurus catenatus). Both are rattlesnakes, identifiable by the rattle at the end of their tails. These two species are protected, reflecting their rarity and declining populations within the state.
The Timber Rattlesnake is the larger of the two, typically ranging from 36 to 60 inches in length. It primarily inhabits the rugged bluffs and valleys of southwestern and western Wisconsin, particularly along the Wisconsin and Mississippi Rivers.
The Eastern Massasauga is smaller, usually measuring between 24 and 30 inches long. It is Wisconsin’s most endangered reptile, with populations found in isolated localities in southeastern, central, and west-central Wisconsin. These snakes prefer wetland habitats such as wet prairies, marshes, and floodplains, often near rivers and lakes.
Identifying Wisconsin’s Venomous Snakes
Identifying Wisconsin’s venomous snakes involves observing specific physical characteristics that differentiate them from the state’s many non-venomous species. Both the Timber Rattlesnake and the Eastern Massasauga are pit vipers, sharing common features like a triangular-shaped head, vertically elliptical (cat-like) pupils, and heat-sensing pits located between their eyes and nostrils. These characteristics are generally absent in non-venomous snakes, which typically have round pupils and more rounded heads.
The Timber Rattlesnake is a heavy-bodied snake with a background color that can vary from yellow, rust-orange, brown, or gray, marked by dark brown to black bands. Its tail is distinctly black and culminates in a tan rattle. Some individuals may also have a narrow reddish-orange stripe running down their back.
The Eastern Massasauga is also thick-bodied, typically grayish-tan with darker brown or black blotches along its back. These blotches may be edged in black, and the snake often has rows of smaller, alternating spots along its sides. Its tail has a distinct rattle, though it can be barely audible or sound insect-like. Unlike the Timber Rattlesnake, the Massasauga often has nine enlarged plate scales on top of its head, and a flattened head with white and dark stripes radiating from its face.
Encountering Snakes: Safety and Coexistence
Encountering a snake in the wild, especially a venomous one, requires a calm and cautious approach. The most important rule is to observe the snake from a safe distance and never attempt to approach, handle, or provoke it. Venomous snakes, like the Timber Rattlesnake, are generally non-aggressive and will typically try to avoid confrontation, often rattling as a warning before striking.
If a snakebite occurs, immediate medical attention is necessary. Call 911 or your local emergency number right away. While waiting for help, remain as still and calm as possible to help slow the spread of venom. Remove any jewelry or tight clothing from the bitten limb before swelling begins and position the bitten area at or below heart level. Clean the wound gently with soap and water, then cover it loosely with a clean, dry dressing.
Crucially, avoid actions that can worsen the situation: do not apply a tourniquet, cut the wound, attempt to suck out the venom, or apply ice. These methods are ineffective and can cause further harm. Do not consume caffeine, alcohol, or pain relievers like aspirin or ibuprofen, as these can interfere with blood clotting.
Remember, most snakebites are not fatal, and prompt, appropriate medical care significantly improves outcomes. Respecting snake habitats and leaving them undisturbed is the best way to ensure safety for both humans and these often misunderstood creatures.