Western Cottonmouth

Agkistrodon piscivorus leucostoma

Western Cottonmouth, Gillespie County, TX

Western Cottonmouth from Gillespie County, Texas

A muddy Cottonmouth from South Carolina.
The pattern on older cottonmouths frequently becomes obscured by dark pigment.
Similar darkening is seen in many of the harmless water snakes (genus Nerodia).