Common Watersnake
Nerodia sipedon • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Nerodia, Species: Nerodia sipedon
Widespread across North America, including eastern and central United States and southeastern Canada. Found from Ontario and Maine south to Georgia and west to Colorado.
Look up Common Watersnake in the Snake Encyclopedia →Venomous Status
Non-venomous; lacks fangs or venom-delivery apparatus.
Danger Level
Harmless to humans. While they are famously defensive and prone to biting if handled, their bite causes only minor scratches and bleeding due to anticoagulants. They pose no significant health risk.
Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Nerodia, Species: Nerodia sipedon
Conservation
Least Concern (IUCN Red List). They are adaptive and common, though they face threats from habitat loss and being frequently killed by humans who mistake them for venomous Cottonmouths.
Physical Description
Heavy-bodied snake with highly keeled scales. Coloration ranges from brownish to grayish with dark crossbands near the head that break into alternating dorsal and lateral blotches further down the body. The head is relatively flat and slightly distinct from the neck; eyes have round pupils.
Size & Dimensions
Typical adults range from 61 to 107 cm (24 to 42 inches). The specimen in the image appears to be an average-sized adult, likely around 70-80 cm.
Habitat
Highly aquatic; found in almost any freshwater environment including lakes, ponds, rivers, marshes, and canals. They prefer slow-moving water and are often seen basking on rocks or logs near the water's edge.
Behavior & Temperament
Diurnal and nocturnal depending on temperature. They are active hunters but extremely defensive when cornered, often flattening their bodies and heads to appear larger, striking repeatedly, and releasing a foul-smelling musk.
Diet & Feeding
Generalist carnivore focusing on aquatic prey. Primarily consumes fish, frogs, toads, salamanders, and occasionally large invertebrates. They use an active foraging strategy, swallowing prey alive.
Reproduction
Viviparous (gives birth to live young). Mating occurs in spring, and females give birth to 15-30 young between August and October.
Venom Profile
Non-venomous - no medically significant venom. However, their saliva contains mild anticoagulants to aid in the ingestion of slippery prey.
Look-alikes
Commonly confused with the venomous Coltonmouth (Agkistrodon piscivorus). Distinct from Cottonmouths by their round pupils (vs. vertical), lack of heat-sensing pits, and labial scales with dark vertical bars. Also resembles the Copperhead, but lacks the distinct 'hourglass' pattern.
Conservation Status
Least Concern (IUCN Red List). They are adaptive and common, though they face threats from habitat loss and being frequently killed by humans who mistake them for venomous Cottonmouths.
Cultural Significance
Ecologically vital as both a major predator of fish and amphibians and a prey source for larger birds and mammals. In many regions, they are culturally misunderstood as dangerous 'water moccasins', leading to unnecessary persecution.
Notable Features
Features extremely rough, keeled scales that give the snake a matte, dull appearance when dry. They are excellent swimmers and can stay submerged for extended periods while hunting or hiding from predators.