Pennsylvania’s diverse landscapes, from dense forests to rocky outcrops and wetlands, provide habitats for a variety of wildlife, including numerous snake species. These reptiles play an integral role in the state’s ecosystems. Understanding the types of snakes found in Pennsylvania, their characteristics, and behaviors can help residents and visitors appreciate these creatures and coexist safely with them.
Overview of Pennsylvania’s Snake Diversity
Pennsylvania is home to 21 native snake species. The vast majority of these snakes are non-venomous and pose no threat to humans. Only three species are venomous: the Eastern Copperhead, the Timber Rattlesnake, and the Eastern Massasauga.
Identifying Venomous Snakes in Pennsylvania
Identifying Pennsylvania’s three venomous snakes accurately is important for safety. All three are pit vipers, sharing characteristics like heat-sensing pits between the eye and nostril, and vertically elliptical pupils. Non-venomous snakes in Pennsylvania, conversely, have round pupils and lack these facial pits.
The Eastern Copperhead (Agkistrodon contortrix)
The Eastern Copperhead (Agkistrodon contortrix) is the most widespread venomous snake in Pennsylvania, found in most areas except the northernmost counties. It is identifiable by its copper or hazel-brown body, often accented with pink or orange, and distinctive dark, hourglass-shaped crossbands that are narrowest across the back. Adults typically range from 24 to 36 inches. While their head is somewhat triangular, pupil shape and facial pits are more reliable indicators. Juvenile copperheads have a yellow-tipped tail, which they may use to lure prey.
The Timber Rattlesnake (Crotalus horridus)
The Timber Rattlesnake (Crotalus horridus) is Pennsylvania’s largest venomous snake, reaching 36 to 54 inches. Their coloration varies from dark brown or black crossbands on a yellow background to almost entirely black individuals. A defining feature is the rattle at the end of their tail, though they do not always rattle before striking. Timber rattlesnakes have a broad, triangular head covered with numerous small scales. Their tail is black near the rattle, regardless of the body’s color phase.
The Eastern Massasauga (Sistrurus catenatus)
The Eastern Massasauga (Sistrurus catenatus) is the smallest of Pennsylvania’s venomous snakes, measuring 20 to 30 inches. This endangered species is found only in specific wetland areas in a few western counties. They have a brown or grayish body with a row of rounded, dark-brown or black blotches down the back, often accompanied by smaller, lighter spots along the sides. Unlike the Timber Rattlesnake, the Massasauga has nine large plates covering the crown of its head. Their rattle is small and produces a subtle buzzing sound, often barely audible from a distance.
Common Non-Venomous Snakes in Pennsylvania
Numerous non-venomous snake species inhabit Pennsylvania. These snakes are harmless to humans and contribute to controlling pest populations. Common species include Garter Snakes, Black Rat Snakes, Milk Snakes, and Ringneck Snakes.
Eastern Garter Snakes (Thamnophis sirtalis)
Eastern Garter Snakes (Thamnophis sirtalis) are widely distributed and recognized by their variable coloration, often with three yellow or white stripes running lengthwise down a greenish or brownish body. They grow to 2 to 4 feet and are active during the day, frequently seen basking or near water sources. They thrive in diverse habitats like gardens, woodlands, and wetlands, consuming earthworms, slugs, and amphibians.
The Eastern Black Rat Snake (Pantherophis alleghaniensis)
The Eastern Black Rat Snake (Pantherophis alleghaniensis) is Pennsylvania’s largest native snake, reaching 42 to 100 inches. These shiny black snakes, though juveniles may be patterned, are excellent climbers, often found in trees, barns, or old buildings where they hunt rodents and birds. They are constrictors, using their strength to suffocate prey. Rat snakes are active during the day in cooler months but become more nocturnal as summer temperatures rise.
Eastern Milk Snakes (Lampropeltis triangulum)
Eastern Milk Snakes (Lampropeltis triangulum) are often mistaken for copperheads due to similar patterns, but they are harmless. They have variable brick-red to brownish blotches bordered in black over a grayish base, and a distinctive white belly with dark splotches in a checkerboard pattern. Milk snakes are 2 to 4 feet long and are secretive, often found under rocks, logs, or in barns where they prey on small rodents and even other snakes.
Northern Ringneck Snakes (Diadophis punctatus edwardsii)
Northern Ringneck Snakes (Diadophis punctatus edwardsii) are small, slender snakes, 10 to 24 inches long, with a distinguishing golden or yellowish ring around their neck. Their bodies are gray, black, or brownish, and their bellies are uniform yellow. These secretive snakes prefer moist, dark environments and are often found under rocks, logs, or leaf litter in forests and grasslands. They are primarily nocturnal hunters.
Where Snakes Live and Safe Encounters
Snakes in Pennsylvania occupy a wide array of habitats. They are commonly found in forested areas, rocky outcroppings, and near water sources like ponds, streams, and marshes. Many species also adapt to human-altered environments, appearing in suburban areas, gardens, woodpiles, and even basements or garages, often in pursuit of prey. Timber rattlesnakes, for instance, prefer mountainous regions with rocky slopes for hibernation and often utilize forest openings for basking. Copperheads are prevalent in rocky areas, wooded hillsides, and near water.
Encountering a snake can be startling, but most prefer to avoid human interaction. If a snake is encountered, observe it from a distance and avoid any attempt to touch, handle, or provoke it. Snakes will move away if given space. If a snake is found in an undesirable location, such as a basement or garage, leave it alone and contact a wildlife professional or local animal control for safe removal. Never try to kill a snake, as most snakebites occur when people attempt to handle or harm them; simple precautions, like watching where you step and place your hands in natural areas, can minimize unexpected encounters.