Pennsylvania is home to two distinct species of rattlesnakes, both venomous pit vipers. While encounters are rare and geographically limited, these two species are a natural part of the state’s wild ecosystems. Understanding their habits and habitats is the most effective way for residents and visitors to safely coexist with these reptiles.
The Two Species of Rattlesnakes in Pennsylvania
Pennsylvania is home to two different rattlesnake species: the Timber Rattlesnake (Crotalus horridus) and the Eastern Massasauga (Sistrurus catenatus). The Timber Rattlesnake is the most widespread and commonly encountered of the two, generally reaching lengths between 36 and 60 inches, making it the state’s largest venomous snake. Their coloration is highly variable, ranging from a bright yellow or gray background with dark crossbands to an almost solid black, but they are consistently heavy-bodied with a large, triangular head and a completely black tail that ends in a rattle.
The Eastern Massasauga is much smaller and significantly rarer, typically measuring only 20 to 30 inches long. This species has a light gray or light brown body marked with dark brown or black blotches outlined with lighter edges. Unlike the Timber Rattlesnake, the Massasauga has nine large scales covering the crown of its head instead of numerous small scales. Both species use their namesake rattle as a warning when they feel immediately threatened.
Where Rattlesnakes Reside in the State
Rattlesnakes are not found throughout the entire state, and their distribution is highly dependent on specific habitat requirements. The Timber Rattlesnake primarily inhabits forested, mountainous regions, particularly across the central and northeastern portions of Pennsylvania. They favor rocky outcrops, talus slopes, and ledges with southern-facing exposures, which they use for basking and as sites for their communal winter dens, or hibernacula.
The Eastern Massasauga has a far more restricted range, primarily confined to small, specific wetland areas in a handful of western Pennsylvania counties, earning it the nickname “swamp rattler.” These areas include wet prairies, bogs, and marshy lowlands near rivers and lakes. Both species are afforded significant legal protection in the state due to population declines from habitat loss and exploitation. The Eastern Massasauga is classified as an endangered species, while the Timber Rattlesnake is a protected species with regulated seasons and possession limits.
Encountering a Rattlesnake Safely
The best way to prevent a rattlesnake encounter is to be aware of their preferred habitats and take simple precautions while outdoors. Wearing sturdy, over-the-ankle hiking boots and long pants provides a layer of protection from unexpected bites. It is important to watch where you place your hands and feet, especially when stepping over logs, gathering firewood, or reaching into rocky crevices.
If you encounter a rattlesnake, freeze immediately to assess the situation. Once you locate the snake, calmly and slowly back away, maintaining a distance of at least five feet, as a snake can strike up to half its body length. Never attempt to handle, harass, or provoke a rattlesnake, as the majority of bites occur when people interfere with the animal.
Should a bite occur, remain calm and seek immediate medical attention by calling 911. Remove any constrictive items like rings or watches from the affected limb, as severe swelling will occur. Keep the bite site at or slightly below the level of the heart to slow the spread of venom. Do not use a tourniquet, cut the wound, attempt to suck out the venom, or apply ice.