Venomous snakes in Missouri

Venomous snakes living in Missouri

5species, plus 1 with rare records

Cottonmouth, Timber rattlesnake, Copperhead, Pygmy rattlesnake, Western massasauga. A bite from any of these is a medical emergency.

How to recognize them

Cottonmouth 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

Timber rattlesnake Crotalus horridus

Dark V- or chevron-shaped bands across the back
Black tail ending in a rattle
Yellow, tan or dark phases; some are almost black

Copperhead 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

Pygmy rattlesnake Sistrurus miliarius

Small with a thin tail and a tiny rattle that sounds like a buzzing insect
Gray or tan with dark round blotches
Often a reddish stripe down the spine

Western massasauga Sistrurus tergeminus

Pale gray with dark brown blotches down the back
Small rattle
Nine large plates on top of the head

Every venomous snake species known from the US is on this site.

Counties with records

None recorded
1 species
2
3 to 4
5 or more

Venomous snakes with open GBIF records, by county: 46 counties so far. Blank does not mean absent.

Active months

Open records of venomous snakes in Missouri by month; most fall in April to May, September to October.

Rare records

Rare records Prairie rattlesnake 1 open record

Harmless snakes people mistake for them

Cottonmouth vs Water Snake Water snake: harmless
Copperhead vs Northern Water Snake Northern water snake: harmless
Cottonmouth vs Banded Water Snake Banded water snake: harmless
Copperhead vs Rat Snake Rat snake: harmless
Copperhead vs Milk Snake Milk snake: harmless
Cottonmouth vs Diamondback Water Snake Diamondback water snake: harmless
Pygmy Rattlesnake vs Hognose Snake Eastern hognose snake: harmless
Copperhead vs Hognose Snake Eastern hognose snake: harmless

Quick answers

Questions

How many venomous snakes are in Missouri?

5 species live in the state: Cottonmouth, Timber rattlesnake, Copperhead, Pygmy rattlesnake and Western massasauga.

Which venomous snakes in Missouri are dangerous?

Cottonmouth, Timber rattlesnake, Copperhead, Pygmy rattlesnake and Western massasauga: a bite is a medical emergency.

When are venomous snakes most active in Missouri?

Most open records fall in April to May, September to October.

Which harmless snakes get mistaken for venomous ones in Missouri?

Water snake, Northern water snake, Banded water snake and Rat snake. See the side-by-side comparisons below.