NNTRC Snakes

Scientific Name

Agkistrodon piscivorus leucostoma

Common Name 

Western Cottonmouth

Physical Characteristics

Length, 30-42 in. (76-107 cm). Longest recorded length 55 in. The smallest of the Cottonmouth subspecies. Olive, brown, or black above with dark dorsal crossbands with non-distinct borders. The crossbands are prominent in young and subadults however, they can be completely dark and patternless as adults.

Geographic Range (USA)

Southern tip of Illinois and west central Kentucky southward to Alabama and west to south central Oklahoma and central Texas.

Map button button

A semiaquatic snake found in lowlands and swampy areas including lakes, rivers, and ditches.


Fish, frogs, snakes, lizards, birds, and small mammals.


Hemorrhagins are the predominant toxins, resulting in extensive tissue damage and edema.


When approached Cottonmouths will usually stand their ground and vibrate their tails. Once thoroughly provoked, they will throw their head up and back with their mouth open wide revealing the white interior.

This page was last updated on: February 11, 2016