Common Watersnake (alternatively Northern Watersnake)
Nerodia sipedon • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Nerodia, Species: Nerodia sipedon
Common throughout Eastern and Central North America, ranging from southern Ontario and Quebec in Canada, south to North Carolina and west to Colorado and Oklahoma.
Look up Common Watersnake (alternatively Northern Watersnake) in the Snake Encyclopedia →Venomous Status
Non-venomous; lacks fangs and a delivery system for medically significant toxins.
Danger Level
Harmless - though they are notoriously defensive when handled and may bite repeatedly or musk, they pose no threat to life and have no venom.
Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Nerodia, Species: Nerodia sipedon
Conservation
IUCN Red List: Least Concern. Generally abundant, though often killed by humans who mistake them for venomous cottonmouths.
Physical Description
Large, heavy-bodied snake with keeled (rough) scales. Coloration is typically dark brown or grayish with lighter crossbands or blotches that are wider than the spaces between them. The head is relatively flat and distinct from the neck; eyes have round pupils.
Size & Dimensions
Typically ranges from 60 to 110 cm (24–42 inches). The specimen in the image appears to be a large adult, likely around 90 cm (3 feet) in length.
Habitat
Found in almost any freshwater environment including lakes, ponds, rivers, marshes, and canals. They prefer slow-moving or quiet water and are often seen basking on logs or rocks.
Behavior & Temperament
Diurnal and crepuscular; highly defensive if cornered or handled. Will flatten its head to appear larger, strike vigorously, and release a foul-smelling musk and feces as a deterrent.
Diet & Feeding
Active forager specializing in aquatic prey. Diet consists primarily of fish (minnows, catfish, sunfish) and amphibians (frogs, toads, salamanders).
Reproduction
Viviparous (gives birth to live young) rather than laying eggs. Females can produce 15 to 30 young per litter, typically in late summer or early autumn.
Venom Profile
Non-venomous - no medically significant venom. Saliva may contain mild anticoagulants to prevent blood clotting in small prey.
Look-alikes
Commonly confused with the venomous Cottonmouth (Agkistrodon piscivorus). Watersnakes have round pupils (Cottonmouths have vertical slits), labial pits (vertical lines on the 'lips'), and lack the dark 'masking' stripe across the eye seen in Cottonmouths.
Conservation Status
IUCN Red List: Least Concern. Generally abundant, though often killed by humans who mistake them for venomous cottonmouths.
Cultural Significance
Often misunderstood and maligned due to its resemblance to the Cottonmouth. Ecologically vital for controlling fish and amphibian populations and serving as a food source for birds of prey.
Notable Features
Excellent swimmers that can dive and remain submerged for extended periods. Their scales are strongly keeled, giving them a very rough texture compared to many other semi-aquatic snakes.