Rattlesnakes are present in Pennsylvania, although encountering one remains rare for most residents and visitors. The state is home to two native species: the widespread Timber Rattlesnake (Crotalus horridus) and the much rarer Eastern Massasauga (Sistrurus catenatus). These species are generally shy and actively avoid human contact, but their presence warrants awareness for anyone spending time in natural areas.
Identifying Pennsylvania’s Rattlesnake Species
Distinguishing between the two rattlesnake species involves noting differences in their size, coloration, and pattern. The Timber Rattlesnake is a large, heavy-bodied snake, with adults typically measuring between 30 to 60 inches in length. Its coloration is highly variable, often appearing in two main phases: a yellow phase featuring dark brown or black crossbands over a sulfur yellow or gray background, and a black phase where the dark bands nearly obscure the lighter ground color. The dark bands often form a distinct chevron, or ‘V’ shape, across the back of the snake, and the tail is conspicuously black, leading up to the rattle.
The Eastern Massasauga is significantly smaller and stouter, with most adults reaching only 20 to 30 inches in length. This species has a lighter ground color of gray or light brown, which is covered with a series of large, dark chocolate-brown blotches down the center of the back and smaller blotches along the sides. A common feature of both species, as with all pit vipers, is the triangular or heart-shaped head and the presence of a rattle. While the Timber Rattlesnake’s rattle is loud and distinct, the Massasauga’s rattle is notably smaller and sounds more like an insect’s buzz, often barely audible beyond a few feet.
Specific Habitats and Conservation Status
The two rattlesnake species occupy very different ecological niches within Pennsylvania, which influences their distribution and conservation status. The Timber Rattlesnake is typically found in mountainous forests, preferring rocky ridges, steep, wooded hillsides, and areas with rock outcrops that provide suitable den sites for overwintering. Males and non-gravid females will travel a mile or more from their dens in the summer to forage, while pregnant females remain close to basking areas near the den. This species is classified as a Candidate species in Pennsylvania, meaning its numbers have decreased significantly from historic records and it remains vulnerable to exploitation and habitat loss.
In contrast, the Eastern Massasauga is highly restricted to specific western counties and is strongly associated with poorly drained, wet habitats. This species utilizes wet grasslands, floodplains, and wetland areas for hibernation, often using crayfish burrows to access underground water tables. Due to extensive habitat loss, the Massasauga is classified as a state Endangered species and a federally Threatened species, with only a few remaining populations known in the state. It is illegal under Pennsylvania Fish and Boat Commission (PFBC) regulations to harass, harm, or remove either species without a permit, with the Massasauga having additional federal protections.
Safety and Prevention When Outdoors
Preventing a rattlesnake encounter begins with awareness and appropriate outdoor gear when hiking or working in potential habitats. Wearing sturdy, over-the-ankle boots and long pants provides protection against an accidental bite. When moving through areas like tall grass, heavy brush, or rocky terrain, watch where you place your hands and feet. Using a walking stick to gently probe the ground or rustle vegetation ahead of you can encourage a snake to move away before you get too close.
If you encounter a rattlesnake, the most important action is to maintain a distance of at least six feet and remain calm. Do not attempt to harass, handle, or provoke the snake, as it will strike only when it feels threatened. Simply pause, slowly back away, and allow the snake to retreat; they generally want to avoid confrontation.
In the rare event of a bite, immediate medical attention is necessary; call 911 or emergency services right away. While waiting for help, remain as calm as possible to slow the spread of venom through your system. The bitten limb should be immobilized and kept in a neutral, comfortable position. Remove any jewelry or tight clothing from the area before swelling begins. Crucially, do not apply a tourniquet, cut the wound, or attempt to suck out the venom, as these actions are ineffective and can cause further tissue damage.