Water moccasins, also known as cottonmouths, are often inquired about regarding their presence in various locations. Many ask if these snakes inhabit Pennsylvania. Understanding their distribution clarifies misconceptions.
Addressing the Presence of Water Moccasins in Pennsylvania
Water moccasins (Agkistrodon piscivorus) are not found in Pennsylvania. Their natural habitat is the southeastern U.S., reaching only southern Virginia. Therefore, any reported sightings in Pennsylvania are almost certainly cases of mistaken identity.
Commonly Confused Snakes in Pennsylvania
The Northern Water Snake (Nerodia sipedon) is the species most frequently mistaken for a water moccasin in Pennsylvania. This non-venomous snake is abundant and shares similar aquatic habitats. They can grow quite large, often ranging from 24 to over 50 inches.
Northern Water Snakes display defensive behaviors that contribute to misidentification. They may flatten their heads and bodies to appear more formidable, giving their head a triangular shape. When cornered, they strike repeatedly; their bites are not venomous, but their saliva contains an anticoagulant that can cause bleeding.
Unlike water moccasins, Northern Water Snakes have round pupils and lack heat-sensing pits between their eyes and nostrils. Their body patterns vary and may become obscure with age. When swimming, they typically keep most of their body submerged, with only their head visible above the water’s surface.
Characteristics of True Water Moccasins
Water moccasins are heavy-bodied snakes, typically 30 to 48 inches long. Their heads are notably triangular, broad, and much wider than their necks. Their eyes have vertical, cat-like pupils, and a deep heat-sensing pit is present between each eye and nostril, a feature absent in non-venomous water snakes.
A unique defensive display involves opening their mouth wide to reveal a stark white interior, giving them their common name “cottonmouth.” Their coloration ranges from olive, brown, or black, often with broad crossbands that may darken with age. Younger moccasins typically exhibit more distinct banding and possess bright yellow or greenish tail tips, which they may wiggle to attract prey. When swimming, water moccasins typically keep their entire body afloat on the water’s surface.
Safe Encounters with Pennsylvania’s Reptiles
Observe any snake in Pennsylvania respectfully from a safe distance, and never attempt to handle or provoke it. Most Pennsylvania snakes are non-venomous and play a beneficial role, often controlling rodent populations. If a snake bite occurs, seek medical attention promptly. Pennsylvania is home to three native venomous snake species—the Eastern Copperhead, Timber Rattlesnake, and the rare Eastern Massasauga Rattlesnake. While bites are uncommon, understanding and respecting these reptiles allows for safe coexistence with the state’s wildlife.