Is the plain-bellied water snake venomous?

The plain-bellied water snake is harmless. Harmless. No dangerous venom. Its habit of crossing open ground away from water leads to a great many mistaken cottonmouth reports.

How do you identify a plain-bellied water snake?

Unmarked bright yellow, orange or red belly with no dark blotching. No dark facial band from eye to jaw.

Where do plain-bellied water snakes live?

They are found in 25 US states, in habitats including water, wetland and woods.

Plain-bellied Water Snake

Harmless

Nerodia erythrogaster · also called red-bellied water snake, yellow-bellied water snake

This is the water snake most often mistaken for an adult cottonmouth, because both are large, dark and patternless. The belly settles it instantly: a plain-bellied water snake has a clean unmarked yellow or orange underside, while a cottonmouth's belly is dark and mottled. It also wanders further from water than other water snakes, and is often found crossing roads and lawns.

Venom: Harmless. No dangerous venom. Its habit of crossing open ground away from water leads to a great many mistaken cottonmouth reports.
Adult length: 24–48 inches (61–122 cm)
Markings: Adults are plain dark olive, grey or brown above with no pattern at all, and a completely unmarked belly that is yellow, orange or red. Juveniles are strongly banded and look like a different species.
Habitat: water, wetland, woods
Family: colubrid
Range: 25 US states

How to identify a plain-bellied water snake

Unmarked bright yellow, orange or red belly with no dark blotching.
No dark facial band from eye to jaw.
Head narrow and continuous with the neck.
Frequently found well away from water, unlike other Nerodia.

What it does when it sees you

Flees quickly on land or water. Will musk and bite if grabbed, and is otherwise entirely inoffensive.

What the plain-bellied water snake is confused with

One test settles each of these.

Cottonmouth →

Look at the belly: plain yellow or orange means water snake, dark and mottled means cottonmouth. Also check for the white gape.

Before anything else

Back away and leave it alone. A snake that can see you leaving has no reason to bite. Most bites in the United States happen to people who picked up, cornered, or tried to kill a snake.
Never handle a snake to identify it. Every identification on this site can be made from a photo or from several feet away.
If someone is bitten, call emergency services now. Keep the limb still and below the heart, remove rings and watches, and go to hospital. Do not cut, suck, apply ice, or use a tourniquet — all of these make outcomes worse.
Do not try to catch the snake for identification. A photo from a distance is enough, and hospitals treat symptoms rather than species.

In the US, the Poison Help line is 1-800-222-1222. This site is a reference, not medical advice.

Not sure it was a plain-bellied water snake? Identify it step by step →