Mississippi Green Watersnake

Nerodia cyclopion
Species of Conservation Concern
Other Common Name
Mississippi Green Water Snake

Colubridae (nonvenomous snakes) in the order Squamata (lizards and snakes)


A medium-sized, dark-colored, heavy-bodied snake, the Mississippi green watersnake was once somewhat common in southeastern Missouri but is now probably extirpated. The back is greenish brown with numerous small, obscure olive-brown or dark brown markings. The belly is dark gray with numerous yellow half-moon-shaped markings. Although not venomous, watersnakes bite viciously to defend themselves and also secrete a strong-smelling musk from glands at the base of the tail.

Similar species: A number of other watersnakes live in Missouri's Bootheel. They all have some combination of prominent bands on the back, or a plain yellow belly, or a yellow belly strongly marked with black patches. Watersnakes are often confused with the venomous western cottonmouth and needlessly killed. The true cottonmouth is more heavy-bodied, with a larger, chunky head; has a facial pit between the nostril and eye on either side of the head; is darker; and has a light line from each eye to the corner of the mouth.


Length: 30 to 45 inches.

Habitat and conservation

Primarily a swamp-dwelling snake. In Missouri, it prefers the cypress swamps and river sloughs of the Mississippi Lowlands.This harmless, semiaquatic snake was once somewhat common in southeastern Missouri but is now quite rare. Due to drastic reductions in native cypress swamps, this species is endangered in Missouri and has not been seen here for many years. It is probably extirpated from our state.


This watersnake feeds mainly on fish, salamanders, frogs, and crayfish.

Mississippi Green Watersnake Distribution Map
Distribution in Missouri

Restricted to the southeastern corner of the state; probably extirpated.


Endangered and probably extirpated in Missouri. Some individuals were spotted in southern Dunklin County in 1994, and several dead specimens have been collected from roads just across the border in Mississippi County, Arkansas. There is reason to hope that some Mississippi green watersnakes may still be found on the Missouri side of the border, enriching our state with their presence.

Life cycle

Active between late March and October, usually on warm days, often basking on branches overhanging water. They hunt for food during early evening or at night when the weather is hot. Courtship and mating apparently occur in April or May. Females give birth to live young (not eggs) during August and early September, with the litter containing some 10-20 young.

Human connections

Often when we think of our interactions with animals, we focus on what they mean to us: Can we eat them, do they harm us, and so on. But with most declining species, the situation is reversed: Our human activities, such as draining swamps, have eliminated most of their ancestral habitat.

Ecosystem connections

As predators, watersnakes control populations of the animals they consume. But snakes are preyed upon themselves. Their defenseless newborns are gobbled by animals ranging from large frogs and fish to other snakes and birds and mammals. Adults are eaten by predatory mammals and birds.