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Diamondback water snake

Nerodia rhombifer · Snakes · Reptiles

Diamondback water snake (Nerodia rhombifer): Large, heavy-bodied watersnake; adults usually 3-5 ft (Missouri: 30-48 in, occasionally to 69 in). Dark brown blotches along the back usually connect into a chainlike pattern, with light diamond-shaped areas between; dark bars on the sides alternate to form diamonds. 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 rhombifer
Family
Colubridae
In North America
Native
Range
Concentrated in the Mississippi River drainage, north to southern Illinois and Indiana, west to Texas and Oklahoma (and Mexico), east into Alabama. Not in Canada.
Biology

How to identify it

Large, heavy-bodied watersnake; adults usually 3-5 ft (Missouri: 30-48 in, occasionally to 69 in). [1][2][3]

Dark brown blotches along the back usually connect into a chainlike pattern, with light diamond-shaped areas between; dark bars on the sides alternate to form diamonds. [1][2][3]

Belly yellow with irregular rows of dark spots or half-moon marks. [1][2][3]

Scales keeled, so the snake feels rough. [1][2][3]

Compared with the northern cottonmouth: Cottonmouth has a distinctly triangular head, a sensory pit between nostril and eye, a light line from eye to mouth corner, and no chainlike dark back pattern. [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 diamondback water snake before you act. Compared with the northern cottonmouth: Cottonmouth has a distinctly triangular head, a sensory pit between nostril and eye, a light line from eye to mouth corner, and no chainlike dark back pattern.[1][2][3]
Field knowledge

Where it lives

Margins and shallows of lakes, ponds, rivers, streams, swamps, marshes, canals and ditches; most common in swamps, sloughs, oxbows and drainage ditches in Missouri. [1][2][3]

Field knowledge

How it behaves

Diurnal in spring and fall and nocturnal in summer; bask on branches, logs and banks except in the hottest weather. [1][2][3]

Eats mainly fishes and frogs, also salamanders, carrion and small turtles; feeds by day. [1][2][3]

Overwinters underground below the frost line, including in crayfish burrows; bites hard and musks when handled. [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

Concentrated in the Mississippi River drainage, north to southern Illinois and Indiana, west to Texas and Oklahoma (and Mexico), east into Alabama. Not in Canada.

Biology

Sources

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

  1. NatureServe · reviewed 2026-09-30

    NatureServe

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

    Missouri Department of Conservation

  3. Alabama Dept. of Conservation and Natural Resources (Outdoor Alabama) · reviewed 2026-09-30

    Alabama Dept. of Conservation and Natural Resources (Outdoor Alabama)