Copperhead vs Cottonmouth

The quick tellCopperheads are lighter, with crisp hourglass bands and a plain coppery head. Adult cottonmouths are dark and heavy, have a dark stripe through the eye and usually stay near water.

Photo: Peter Paplanus, CC BY 2.0, via Wikimedia Commons

Copperhead

Medically significant · Agkistrodon contortrix

Copper to tan body with dark hourglass bands: wide on the sides, narrow on the spine
Plain coppery head with no pattern
Young snakes have a bright yellow-green tail tip
Cat-like vertical pupils and a pit between eye and nostril

Size: 24–36 in. Habitat: Wooded hillsides, rocky ridges, wood piles and suburban yards in the East and South.

The venomous snake behind most bites in the eastern US. Bites are painful and need medical care, but deaths are extremely rare.

Photo: kirk gardner, CC BY 4.0, via iNaturalist

Cottonmouth

Dangerous · Agkistrodon piscivorus

Heavy, dark olive to black body; bands fade with age
Broad flat head with a dark stripe through the eye
Swims with the whole body high on the water
Opens its mouth wide to show the white lining when threatened

Size: 30–48 in. Habitat: Swamps, slow rivers, marshes and ditches of the Southeast.

A bite is a medical emergency. Most snakes people call water moccasins outside its range are harmless water snakes.

Where each one lives

Copperhead only
Cottonmouth only
Both
Neither

Copperhead: 28 states. Cottonmouth: 15 states. Both live in 15 states.

Side by side

	Copperhead	Cottonmouth
Danger	Medically significant	Dangerous
Size	24–36 in	30–48 in
States	28	15
Habitat	Wooded hillsides, rocky ridges, wood piles and suburban yards in the East and South	Swamps, slow rivers, marshes and ditches of the Southeast

Questions

How can you tell a copperhead from a cottonmouth?

Copperheads are lighter, with crisp hourglass bands and a plain coppery head. Adult cottonmouths are dark and heavy, have a dark stripe through the eye and usually stay near water.

Which one is dangerous?

The copperhead: medically significant. The cottonmouth: dangerous. If you are not sure, keep your distance and do not handle it.

Where do both live?

Both live in 15 states: Alabama, Arkansas, Florida, Georgia, Illinois, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Tennessee, Texas and Virginia.