A non-venomous water snake constantly mistaken for the venomous cottonmouth (water moccasin) — and consequently killed by frightened fishermen and homeowners. Their range minimally overlaps with cottonmouths.

Also called: Northern Water Snake, Common Water Snake, Banded Water Snake

Native status: Native to eastern and central US

§ Quick facts

SizeLength 60–135 cm (24–53 in); rarely to 150 cm
Weight150–600 g
LifespanWild typically 9 years; captive 14
OrderSquamata
FamilyColubridae

§ Encyclopedia

The common watersnake is a species of large, nonvenomous, common snake in the family Colubridae. The species is native to North America. It is frequently mistaken for the venomous cottonmouth.

Source: Wikipedia — Common watersnake Licensed under CC BY-SA 4.0

§ Identification

Field marks. Medium-large stocky snake with brown, gray, or reddish-brown body bearing dark crossbands across neck transitioning to alternating blotches mid-body; pale belly with reddish-orange half-moon markings.

Similar species. Cottonmouth (venomous; range only in southeastern US; cotton-white mouth lining when threatened; very different body proportions). Plain-bellied Water Snake (no belly markings).

Voice. Hisses defensively; sometimes vibrates tail rapidly.

§ Diet & behavior

Diet. Fish (~75% of diet), amphibians (frogs, salamanders, tadpoles), crayfish. Catches prey by ambush in water.

Behavior. Frequently misidentified as venomous Cottonmouth (Water Moccasin), leading to needless killing. Northern Water Snake is non-venomous and lives in northern habitats where Cottonmouths do not occur. Defends itself aggressively when handled — bites readily and releases a foul-smelling musk. Bites are non-venomous but inflict significant pain due to needle-like teeth.

§ Range

Eastern and central US, parts of Canada

§ Habitat

Lakes, rivers, ponds, marshes

§ Threats

Persecution from misidentification, vehicle strikes, water pollution.

§ Conservation status

According to the IUCN Red List, the northern water snake is currently classified as Least Concern.

§ What helps

Learn to distinguish water snakes from cottonmouths (vastly different ranges). Don't kill snakes. Support clean water rules.

Support our work More ways to help

§ Further reading

§ Sources cited

  • Davidson College Department of Biology
  • Virginia Herpetological Society
  • iNaturalist
  • IUCN Red List 2007