Pennsylvania is home to various snake species. While most are harmless, three native species are venomous. Knowing how to identify these snakes and what to do in an encounter or bite situation is important for safety.
Native Venomous Species
Pennsylvania has three native venomous snake species: the Timber Rattlesnake (Crotalus horridus), the Eastern Copperhead (Agkistrodon contortrix), and the Eastern Massasauga Rattlesnake (Sistrurus catenatus). These pit vipers are non-aggressive and typically bite only when threatened or provoked.
The Timber Rattlesnake is the largest venomous snake in Pennsylvania, reaching 3 to 5 feet. Its coloration varies, featuring dark brown or black chevron-shaped bands on a yellow, gray, or black background, with a black tail ending in a rattle. These snakes are primarily found in mountainous regions and rugged, forested terrains, using rocky ledges and outcrops for basking and hibernation. They are ambush predators, feeding on small mammals like mice and chipmunks.
The Eastern Copperhead is the most common venomous snake in Pennsylvania, found in most areas except the northernmost counties. Copperheads are identifiable by their distinctive hourglass-shaped crossbands, wider on the sides and narrower across the back, against a reddish-tan to pinkish-tan body. They grow to 2 to 3 feet long and prefer habitats such as rocky areas, wooded hillsides, and suburban environments.
The Eastern Massasauga Rattlesnake is the least common and an endangered species in Pennsylvania, found only in a few western counties. This smaller rattlesnake averages 20 to 30 inches in length and has a light gray or brown body with large, dark brown or black blotches edged in lighter colors along its back. It inhabits poorly drained wetland areas, including swamps, and relies on crayfish burrows for hibernation. The Eastern Massasauga’s rattle produces a quiet, insect-like buzz that is often barely audible beyond a few feet.
Recognizing Venomous Snakes
Identifying venomous snakes in Pennsylvania involves looking for several common characteristics, though some non-venomous snakes can mimic these features. Most venomous snakes in the state, which are pit vipers, possess a triangular or spade-shaped head distinctly wider than their neck. This contrasts with the more slender, uniform head shape of many non-venomous species.
Another indicator is pupil shape; venomous pit vipers have vertical, slit-like pupils, similar to a cat’s eye, especially in bright light. Non-venomous snakes have round pupils. A third characteristic of pit vipers is the presence of loreal pits, small, heat-sensing organs located between the eye and nostril on each side of the head. These pits are absent in non-venomous snakes.
While coloration and patterns offer clues, they are not always definitive. Venomous copperheads and rattlesnakes have ridged or keeled scales, giving them a less shiny, more textured appearance. Rattlesnakes also possess a rattle at the end of their tail that produces a distinct sound when vibrated. However, a rattlesnake may not always rattle before striking.
Safety Measures and Emergency Response
When encountering any snake, maintain a respectful distance and avoid disturbing it. Snakes typically bite only when threatened, so give them space to retreat. Wear appropriate footwear and watch where you step or place hands, especially in rocky or wooded areas, to prevent accidental encounters.
If bitten, remain calm to slow venom spread. Immediately call 911 or seek urgent medical attention. While waiting for medical help, gently wash the bite area with soap and water if available, and remove any jewelry or tight clothing from the affected limb, as swelling is likely. Keeping the bitten area still and, if possible, below heart level can help slow venom circulation.
Avoid certain actions after a snakebite, as they can cause more harm than good. Do not attempt to cut the wound or suck out the venom, as these methods are ineffective and can introduce infection. Do not apply a tourniquet, ice, or consume alcohol or caffeine. The most effective treatment for venomous snakebites is antivenom, administered by medical professionals.