Venomous Snakes of Wisconsin & Common Look-Alikes!

Wisconsin is home to only two species of venomous snakes, the Eastern Massasauga (Sistrurus catenatus) and the Timber Rattlesnake (Crotalus horridus), both of which are rattlesnakes. All other snakes native to Wisconsin are either nonvenomous or harmless to humans and do not have rattles on their tails. The two species we do have in the state of Wisconsin both receive protected status, meaning they are either “protected” wild animals or “endangered”, and are by no means abundant or likely to be encountered by most who enjoy the outdoors. This handout is a quick Identification guide to the 2 species we do have here in Wisconsin and several of the more common, widespread nonvenomous species we have that commonly display appearances and/or behaviors leading to the mistaken identity of a venomous snake.

Wisconsin Venomous Species

Timber Rattlesnake (Crotalus horridus) WPCT
-36-54” (3-5 feet).
-Rugged, remote bluffs of western/southwestern WI
-Distinct rattle on black tail.

Eastern Massassauga (Sistrurus catenatus) END.
-24-30” (2-2 ½ feet).
-Remote, swampy bottomlands of west central WI
-Distinct rattle present on tail. Rattle may be barely audible, or insect-like.

Eastern Foxsnake (Panthertophis vulpinus)
-36-54” (3-5 feet).
-Yellowish to brownish with darker blotches.
-Reddish-Orange head as adult; Not a Copperhead.

Eastern Milk snake (Lampropeltis triangulum)
-24-36” (2-3 feet).
-Grayish to brownish with reddish-brown blotches.
-“Y” or “V” marking on back of head; bright red blotches when young.

Northern Watersnake (Nerodia sipedon)
-24-48” (2-4 feet).
-No rattles on tail.
-Brown, grayish, or reddish-brown banding, blotched, or dark colored.
-Not a “Cottonmouth” or a “Water Moccasin”.

Bullsnake (Pituophis catenifer sayi)
-48-72” (4-6 feet).
-Small, heavily mottled head.
-Three toned in color/appearance; From blackish, reddish or reddish-brown, to yellowish with darker reddish brown to brown blotches, saddles, and rings towards tail.
-Hisses very loudly when disturbed. Largest snake species in Wisconsin.

Eastern Hognose Snake (Heterodon platirhinos)
-18-30” (1 ½-2 ½ feet).
-Variable in color and pattern; Can be light or dark brown, tan, yellow, olive, gray, reddish, or pinkish. Young usually more vibrantly colored and patterned.
-Upturned snout and unique defensive behavior consisting of flattening and spreading out head and neck like a cobra, and hissing loudly. May also pretend to strike.
-May also turn over and play dead as another defense.

DeKay’s Brownsnake (Storeria dekayi)
-Small species of snake as adults. 8-15” (less than 1 foot to 1 ½ feet).
-Usually light brown to grayish in color.
-Small linear dots along back and light colored stripes.