Northern Cottonmouth
Agkistrodon piscivorus
A stout, semi-aquatic pit viper of southeastern wetlands, named for the white lining of its mouth displayed as a threat.
- Adult length
- 0.8-1.2 m (2.6-4 ft)
- Range
- Southeastern United States
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Overview
The Northern Cottonmouth is a heavy-bodied, semi-aquatic pit viper closely tied to wetlands, swamps, and slow-moving waterways of the southeastern United States. It is well known for its dramatic open-mouth threat display, revealing the white interior that gives it its common name.
How to identify it
- Heavy-bodied with dark olive, brown, or nearly black coloration, sometimes with faint banding visible up close
- Broad, blocky head distinct from the neck
- Heat-sensing pit between eye and nostril
- Vertically elliptical pupils
- Swims with its body riding high on the water's surface, unlike many water snakes that swim mostly submerged
- White interior of mouth displayed when threatened
Habitat & range
Inhabits swamps, marshes, lake margins, sluggish rivers, and other wetland habitats across the southeastern United States, occasionally venturing into brackish coastal waters.
Behavior, diet & reproduction
Primarily nocturnal in warm weather, more diurnal in cooler seasons. Opportunistic feeder on fish, amphibians, small mammals, and carrion. Viviparous, bearing live young. Known for its gaping white-mouth display.
Frequently asked questions
How can I tell it from a water snake?
Cottonmouths swim with their bodies riding high on the water and have a blocky head with heat pits, unlike slimmer, submerged-swimming water snakes.
What does it eat?
It is an opportunistic feeder on fish, amphibians, small mammals, and carrion.
Where does it live?
It inhabits wetlands, swamps, and slow-moving waters across the southeastern United States.
Northern Cottonmouth guides
In-depth guides for identifying and understanding Northern Cottonmouth.
Northern Cottonmouth identified by the community
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