Western Cottonmouth

Viperidae (venomous snakes) in the order Squamata (lizards and snakes)

The name “cottonmouth” is from the whitish lining of its mouth. When alarmed, it opens its mouth widely, showing the cotton-white lining. The body is black with little or no pattern or dark brown with darker bands on the back. Belly is dark brown or black. Young cottonmouths are patterned something like a copperhead and usually have a yellowish-green tail. Like all venomous snakes in Missouri, cottonmouths have a hole between the nostril and the eye, and the pupils are vertical, like a cat’s.

Length: 30–42 inches.
Habitat and conservation: 
This species lives in two distinctly different habitats; in southeastern Missouri, they live in swamps and oxbow lakes, and in the southern Ozarks, they live in cool, spring-fed rocky creeks and river sloughs. The cottonmouth is a dangerously venomous species that can deliver a fatal bite. Various harmless snakes often are misidentified as cottonmouths and needlessly killed. Learn to identify them and refrain from destroying snakes. All Missouri snakes are protected by law.
A semi-aquatic predator. Primarily a fish-eater but also eats frogs, other snakes, lizards and rodents. Young have a greenish-yellow tail and use it like a lure to attract frogs, lizards and other prey.
Distribution in Missouri: 
Southeastern corner; a spotty distribution throughout the Ozark Region. None occur north of the Missouri River in our state.
Has a limited range in Missouri. Missouri is the northwestern limit of this species. Low winter temperatures limit its distribution.
Life cycle: 
Active from late April through early October. They bask in the sun in spring and autumn but are mainly nocturnal. In autumn, they often move from their swamps to bluffs to overwinter in ledges, often with other species of snakes. Courtship and mating are most prevalent in the spring. Cottonmouths give birth in August and September; litters average 6 or 7 young. Females probably give birth only every other year.
Human connections: 
People instinctively fear venomous snakes, yet they intrigue us and are deeply significant for human cultures all over the world. Learning about them helps us to coexist with these creatures that remain a vital part of the natural order.
Ecosystem connections: 
Snakes are an integral part of the wildlife community and play vital roles in their respective ecosystems. They are also protected by Missouri's Wildlife Code. While snakes can evoke irrational fear in those who encounter them, it is still unlawful to kill, harm or harass them.