Common Watersnake
Nerodia sipedon • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Nerodia, Species: Nerodia sipedon
Eastern and Central North America, ranging from southern Ontario and Quebec in Canada, south to North Carolina and west to Colorado and the Mississippi River area.
Look up Common Watersnake in the Snake Encyclopedia →Venomous Status
Non-venomous
Danger Level
Harmless / Low Risk. While non-venomous, they are famously quick to strike and bite repeatedly if handled, and their saliva contains an anticoagulant which can cause profuse bleeding at the puncture site.
Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Nerodia, Species: Nerodia sipedon
Conservation
Least Concern (IUCN). Generally abundant, though occasionally persecuted by humans who mistake them for venomous species or blamed for depleting fish stocks.
Physical Description
A heavy-bodied snake with strongly keeled scales. Coloration is typically brown, tan, or grayish with dark crossbands near the head that break into alternating dorsal and lateral blotches further down the body. Older individuals, like this specimen, often darken significantly, becoming almost uniformly black or dark brown. The belly is usually light with reddish or black crescent-shaped spots.
Size & Dimensions
This specimen appears to be an adult, approximately 24 to 36 inches (60-90 cm). The species typically ranges from 24 to 42 inches in length, with a maximum recorded length of about 55 inches.
Habitat
Semi-aquatic. Found near freshwater sources including rivers, lakes, ponds, marshes, and canals. They prefer basking on logs or rocks near the water's edge and are often found in low-elevation riparian zones.
Behavior & Temperament
Highly defensive and flighty. Usually attempts to flee into the water when approached. If cornered or grabbed, they flatten their bodies to appear larger, emit a foul-smelling musk from the cloaca, and bite aggressively. They are primarily diurnal but can be active at night during hot weather.
Diet & Feeding
Specialized carnivore. Primarily feeds on fish and amphibians (frogs, toads, salamanders). They use an active foraging strategy, swimming through water and debris to corner prey, which they swallow alive without constriction.
Reproduction
Viviparous (gives birth to live young). Mating occurs between April and June, with females giving birth to 15-30 young (sometimes up to 100) in late summer or early fall.
Venom Profile
Non-venomous - no medically significant venom.
Look-alikes
Commonly confused with the venomous Northern Cottonmouth (Agkistrodon piscivorus). To distinguish: Nerodia have round pupils (Cottonmouths have vertical slits), lack heat-sensing pits between the eye and nostril, and have labial scales (lip scales) with dark vertical bars.
Conservation Status
Least Concern (IUCN). Generally abundant, though occasionally persecuted by humans who mistake them for venomous species or blamed for depleting fish stocks.
Cultural Significance
Historically misunderstood and frequently killed due to their resemblance to Agkistrodon species. Ecologically, they are vital for controlling populations of fish and amphibians and serve as a prey source for larger predators.
Notable Features
Notable for their extreme darkening (ontogenetic color change) as they age, their ability to dive and remain underwater for extended periods, and their highly irritable temperament which serves as a successful deterrent to predators.