Northern Cottonmouth vs. Plain-bellied Watersnake

Both are heavy, dark, nearly plain snakes of southern Illinois swamps, and both are often called water moccasins. The Cottonmouth has a broad, blocky head much wider than its neck (a watersnake's head is narrow), a dark band through the eye edged above with a pale line, a vertical pupil and a pit between the eye and the nostril; the Plain-bellied Watersnake has none of these, and its belly and lips are plain red-orange or yellow. A Cottonmouth gapes to show a white mouth when cornered.

Photographs via iNaturalist under Creative Commons licences; the photographers are credited on the sheet.

More comparisons

• Northern Cottonmouth vs. Common Watersnake
• Northern Cottonmouth vs. Diamondback Watersnake
• Northern Cottonmouth vs. Mississippi Green Watersnake
• Northern Cottonmouth vs. Eastern Copperhead
• Banded Watersnake vs. Northern Cottonmouth
• Broad-banded Copperhead vs. Northern Cottonmouth
• Brown Watersnake vs. Northern Cottonmouth
• Florida Cottonmouth vs. Northern Cottonmouth
• Florida Green Watersnake vs. Northern Cottonmouth
• Eastern Copperhead vs. Plain-bellied Watersnake
• Common Watersnake vs. Plain-bellied Watersnake
• Plain-bellied Watersnake vs. Diamondback Watersnake
• Mississippi Green Watersnake vs. Plain-bellied Watersnake
• Mudsnake vs. Plain-bellied Watersnake
• Banded Watersnake vs. Plain-bellied Watersnake
• Broad-banded Copperhead vs. Plain-bellied Watersnake
• Glossy Swampsnake vs. Plain-bellied Watersnake
• Saltmarsh Snake vs. Plain-bellied Watersnake
• Brazos River Watersnake vs. Plain-bellied Watersnake
• Concho Watersnake vs. Plain-bellied Watersnake
• Brown Watersnake vs. Plain-bellied Watersnake
• Black Swampsnake vs. Plain-bellied Watersnake
• Florida Cottonmouth vs. Plain-bellied Watersnake
• Florida Green Watersnake vs. Plain-bellied Watersnake

Wildsight identifies the reptiles and amphibians of the United States. Every comparison