Common Watersnake
Nerodia sipedon • Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Nerodia, Species: Nerodia sipedon
Widely distributed throughout central and eastern North America, from southern Ontario and Quebec in Canada, south through the eastern United States to the Gulf Coast, and west to the edge of the Great Plains.
Look up Common Watersnake in the Snake Encyclopedia →Venomous Status
Non-venomous (Aglyphous - lacks specialized venom-delivering fangs).
Danger Level
Harmless. While they are non-venomous, they are famously defensive and will bite repeatedly if handled, often accompanied by the release of a foul-smelling musk and cloacal discharge.
Family
Order: Squamata, Suborder: Serpentes, Family: Colubridae, Subfamily: Natricinae, Genus: Nerodia, Species: Nerodia sipedon
Conservation
Least Concern (IUCN). They are abundant across their range, though they face threats from habitat destruction and frequent persecution by humans who mistake them for venomous cottonmouths.
Physical Description
A heavy-bodied snake with strongly 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 distinct from the neck, and the pupils are round.
Size & Dimensions
The specimen in the image appears to be a sub-adult or adult, likely between 60-90 cm. Typical adult size for the species is 61 to 107 cm, with a record maximum of 152 cm.
Habitat
Semi-aquatic; found in or near freshwater sources such as lakes, ponds, rivers, marshes, and canals. They are often seen basking on rocks, logs, or overhanging branches. They range from sea level to approximately 1,500 meters in elevation.
Behavior & Temperament
Diurnal during cooler months and more nocturnal during hot summer periods. Highly defensive temperament; they will flatten their heads to appear larger and strike vigorously if cornered. Excellent swimmers and divers.
Diet & Feeding
Primarily piscivorous and insectivorous. Feeds on fish, frogs, toads, salamanders, and occasionally small mammals or large insects. They are active hunters that search through aquatic vegetation or wait in ambush.
Reproduction
Viviparous (gives birth to live young). Breeding occurs in spring, with females giving birth to 15-30 young in late summer or early fall. No parental care is provided after birth.
Venom Profile
Non-venomous - no medically significant venom. Saliva may contain mild anticoagulants to aid in swallowing prey.
Look-alikes
Commonly confused with the venomous Northern Cottonmouth (Agkistrodon piscivorus). Distinct from Cottonmouths by their round pupils (vs. vertical slits), lack of heat-sensing pits, and labial scales with dark vertical lines.
Conservation Status
Least Concern (IUCN). They are abundant across their range, though they face threats from habitat destruction and frequent persecution by humans who mistake them for venomous cottonmouths.
Cultural Significance
Often misunderstood and feared, leading to high mortality from human encounter. Ecologically, they are vital for controlling populations of fish and amphibians and serve as prey for larger birds and mammals.
Notable Features
Features a 'Labial Bar' pattern (vertical dark lines on the scales bordering the mouth). Their strongly keeled scales give them a very rough, matte appearance compared to many other semi-aquatic species.