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Green water snake

Nerodia cyclopion · Snakes · Reptiles

Green water snake (Nerodia cyclopion): Medium-sized, heavy-bodied, dark semiaquatic snake, averaging 30-45 in. Back greenish brown with obscure olive-brown or dark markings and dim black crossbars; belly dark grey or brown with yellow half-moon markings. This profile does not establish whether taking it is legal anywhere.

Check rules for a place and date

Certified rules currently represented in Hunt: coverage in development. This is coverage, not a legal answer.

Scientific name
Nerodia cyclopion
Family
Colubridae
In North America
Native
Range
Coastal Plain from extreme western Florida and southern Alabama to southeastern Texas and north in the Mississippi Valley to southeastern Missouri and southern Illinois.
Biology

How to identify it

Medium-sized, heavy-bodied, dark semiaquatic snake, averaging 30-45 in. [1][2][3]

Back greenish brown with obscure olive-brown or dark markings and dim black crossbars; belly dark grey or brown with yellow half-moon markings. [1][2][3]

A short row of small subocular scales between the eye and the upper-lip scales separates it from other Missouri watersnakes. [1][2][3]

Keeled scales; females larger than males. [1][2][3]

Compared with the northern cottonmouth: Cottonmouth is heavier-bodied with a chunky head, a facial pit between nostril and eye, and a light line from eye to mouth corner. [1][2][3]

Compared with the plain-bellied water snake: Other Bootheel watersnakes have prominent bands, a plain yellow belly or a yellow belly with black patches. [1][2][3]

Species it is confused with

Check these before deciding what you are looking at. If you are not certain what it is, do not shoot.

Field notes

  • Identification Confirm a green water snake before you act. Compared with the northern cottonmouth: Cottonmouth is heavier-bodied with a chunky head, a facial pit between nostril and eye, and a light line from eye to mouth corner.[1][2][3]
Field knowledge

Where it lives

Cypress swamps, river sloughs, marshes, bayous, ditches, shallow lakes, oxbows and tree-lined sluggish streams, sometimes brackish Gulf Coast marshes. [1][2][3]

Field knowledge

How it behaves

Basks on logs, brush and banks, seldom far from water; flattens body and releases foul musk when disturbed. [1][2][3]

Primarily diurnal in Illinois, almost exclusively nocturnal in Texas; hunts late evening. [1][2][3]

Eats fish, frogs, salamanders, tadpoles, small turtles and invertebrates; live-bearing, young born August-September. [1][2][3]

Regulatory handoff

Limited legal take

Legal take of this species exists only under narrow conditions — a quota, a draw, a permit, a small area, or animals released or held on private land — set by the authorities below. Nowhere else is a legal opportunity implied, and Hunt shows one only where a certified rule establishes it.

Where legal take is listed

Being listed is not an open season. Seasons, zones, licences, methods and limits decide whether this animal may be taken on a given day and place — check Hunt or the authority before you go. Listings read 2026-09-30.

Geospatial intelligence

Where it is found

Coastal Plain from extreme western Florida and southern Alabama to southeastern Texas and north in the Mississippi Valley to southeastern Missouri and southern Illinois.

Biology

Sources

Every claim above is attributed to one of these published sources.

  1. NatureServe · reviewed 2026-09-30

    NatureServe

  2. Illinois Department of Natural Resources · reviewed 2026-09-30

    Illinois Department of Natural Resources

  3. Missouri Department of Conservation · reviewed 2026-09-30

    Missouri Department of Conservation