Wisconsin Snakes Identification Guide (With Pics & Expert Advice)

Wisconsin snakes may not include the most outstanding snake diversity in the United States, but this northern state boasts an impressive 21 species.

From smaller snakes that look like worms, to snakes that climb trees, there are plenty of Wisconsin snakes to see.

You’ll find the most common, most dangerous, and most iconic species in this identification guide. I’ve created detailed profiles, including pictures, of snakes in Wisconsin.

Read through the end to discover how to safely exist side-by-side with these reptiles and pick up some valuable contacts.

In Short

  • There are 21 species of snakes native to Wisconsin.
  • If you see a snake in the wild, give it some space, and it won’t bother you.
  • Only eight species are hardy enough to tolerate the climates of Northern Wisconsin.
  • There are just two species of venomous snakes found in Wisconsin; the Timber Rattlesnake and Eastern Massasauga.

Snake Identification Basics

Snake characteristics often vary geographically. This guide is only for identifying Wisconsin snakes.

Some snakes found in Wisconsin have similar features that are easy to mistake for each other.

When attempting to identify a snake, there are several components to take into consideration:

  • Size – The length of a snake can help you set it apart from other species with similar appearances.
  • Pupil Shape – Both venomous species in Wisconsin have elliptical pupils, while nonvenomous species have round pupils.
  • Color and Pattern – Some snakes may have a solid green coloration, while others have elaborate patterns or distinctive identifying marks.
  • Habitat and Location – Most snakes have defined ranges and specific habitat preferences.

Correctly identifying snakes can be tricky. You’re most likely to reach an accurate conclusion when integrating all these elements.

Quickly Identifying Venomous Snakes in Wisconsin

There are only two species of venomous snakes (often mislabeled as poisonous snakes) in Wisconsin. Both belong to a group of snakes known as pit vipers.

Pit vipers have several notable characteristics:

  • Rattle – Both species have distinct rattles made of hollow scales on the end of their tails.
  • Elliptical Pupils – These are the only Wisconsin snakes with elliptical, cat-like pupils.
  • Heat-Sensing Pits – They have sensory pits located between the eye and nostril on each side to assist with locating prey.
  • Triangular Heads – Their heads are broad and shaped like an arrow to accommodate the venom glands located on the sides of the head.

It’s worth noting that although these features are excellent identifiers, many snakes have evolved to look or act like deadly vipers.

You’re also most likely to see these characteristics at close-range, which could present a dangerous situation.

If you ever doubt a snake’s identity, always err on the side of caution.

Timber Rattlesnake

Timber Rattlesnake coiled up surrounded grass and dead leaves
Timber rattlesnakes have many common names, including canebrake rattlesnakes, American vipers, and Eastern rattlesnakes.

Scientific Name:

Crotalus horridus

Range:

Western and Southwestern Wisconsin

Adult Size:

36-60 inches

Description:

Heavy-bodied

Keeled scales

Rattle at the end of the tail

Elliptical pupils on a broad head

Pits between each eye and nostril

Yellow, rust-orange, brown, or grey with brown or black V-shaped bands. May have a light vertebral stripe

Habitat:

Deciduous forests, woodlands, prairies, and cliffs

Diet:

Small mammals, birds, frogs, and other snakes

Venomous/Non-Venomous:

Venomous

Eastern Massasauga

Eastern massasauga on the ground surrounded by grass, rocks, and dead leaves
The Eastern Massasauga often utilizes crayfish burrows for hibernation.

Scientific Name:

Sistrurus catenatus

Range:

Southeastern, central, and Southcentral Wisconsin

Adult Size:

20-32 inches

Description:

Keeled scales

Short and heavy-bodied

Elliptical pupils on a wide head

Pits between the eye and nostril

Small rattle at the end of the tail

Gray or brownish-gray with dark markings along the back and sides. Dark stripe from the eye to the jaw

Habitat:

Floodplain habitats and open canopy wetlands

Diet:

Small mammals, lizards, frogs, other snakes, and invertebrates

Venomous/Non-Venomous:

Venomous

Most Common Snakes in Wisconsin

The number of snake sightings people report on websites like iNaturalist allows us to see which species are the most abundant.

Here are the most widespread Wisconsin snakes, in order of most common to least common:

  1. Common Garter Snakes
  2. Red-Bellied Snake
  3. Common Watersnake
  4. Eastern Fox Snake
  5. DeKay’s Brown Snake
  6. Eastern Hognose Snake
  7. Eastern Milk Snake

Let’s take a closer look at each species.

Common Garter Snakes

There are five species of garter snakes in Wisconsin:

  1. Plains Gartersnake
  2. Butler’s Gartersnake
  3. Eastern Ribbon Snake
  4. Common Gartersnake
  5. Western Ribbon Snake

These snake species can be difficult to distinguish, but you can find identification tips here.

Not only is the common garter snake the most abundant Thamnophis species found in Wisconsin, but also the most common snake species in the state.

Eastern Garter Snakes on top of each other around dead leaves and twigs
The common garter snake only lives an average of two years in the wild.

Scientific Name:

Thamnophis sirtalis

Range:

Statewide

Adult Size:

17-26 inches

Description:

Keeled scales

Round pupils

Black, brown, or green with three lightly colored lines

Habitat:

Habitat generalists, favoring forests edges and open canopy wetlands

Diet:

Amphibians, fish, insects, and earthworms

Venomous/Non-Venomous:

Non-venomous

Red-Bellied Snake

Red-Bellied Snake on top of dead twigs and leaves
When it’s eating or feels threatened, the red-bellied snake curls its lip to expose its maxillary teeth.
Image Credit: Todd W Pierson (via creativecommons.org)

Scientific Name:

Storeria occipitomaculata

Range:

Statewide

Adult Size:

8-10 inches

Description:

Round pupils

Bright red or orange ventral scales

Reddish-brown or steel-gray with a wide dorsal stripe and a narrow stripe on each side

Habitat:

Forests, bogs, and fields along forests edges

Diet:

Slugs, earthworms, and insect larvae

Venomous/Non-Venomous:

Non-venomous

Common Watersnake

Water snakes in Wisconsin are often mistaken for venomous cottonmouths, which don’t live in this state.

Northern Water Snake on top of tree branch
Water snakes are viviparous, meaning they give birth to live young.

Scientific Name:

Nerodia sipedon

Range:

Statewide

Adult Size:

24-40 inches

Description:

Round pupils

Heavy-bodied

Grey, brown, or tan with dark bands (patterns fade with age)

Ventral scales are white speckled with gray and red half-moon-shaped markings

Habitat:

In or near permanent bodies of water

Diet:

Crayfish, fish, and amphibians

Venomous/Non-Venomous:

Non-venomous

Eastern Fox Snake

The eastern fox snake, also called a pine snake in Wisconsin, is commonly found in homes throughout the state.

It’s often unnecessarily killed when mistaken for venomous species like copperheads or rattlesnakes.

Copperheads don’t live in Wisconsin, and fox snakes can be distinguished from rattlesnakes by their pointed tails that lack rattles.

Eastern Fox Snake on top of grass
The fox snake’s scientific name, vulpinus, means “fox-like.”
Image credit: dmills727 (via creativecommons.org)

Scientific Name:

Pantherophis vulpinus

Range:

Statewide

Adult Size:

36-56 inches

Description:

Round pupils

Yello, tan, or olive-gray with reddish-brown or dark brown blotches

Habitat:

Open habitats; marshes, meadows, prairies, fields, and near human homes

Diet:

Rodents, birds, and occasionally amphibians

Venomous/Non-Venomous:

Non-venomous

DeKay’s Brown Snake

 DeKay's Brown Snake coiled on a branch
Brown snakes have specialized jaws to remove snails from their shells.

Scientific Name:

Storeria dekayi

Range:

Most of Wisconsin, except several northcentral counties

Adult Size:

8-15 inches

Description:

Round pupils

Ventral scales are white or light pink with spots along the edges

Gray or light brown with a light dorsal stripe bordered with dark spots

Habitat:

A variety of habitats, including savannas, prairies, southern lowland hardwoods, marshes, fields, and urban areas

Diet:

Slugs, earthworms, and snails

Venomous/Non-Venomous:

Non-venomous

Eastern Hog-Nosed Snake

Eastern Hog-Nosed Snake
When an Eastern hognose snake is threatened, it flattens out its neck and hisses loudly, earning it the nickname “puff adder.”
Image credit: (via CreativeCommons.org)

Scientific Name:

Heterodon platirhinos

Range:

Most of the state, excluding the Eastern border and parts of northcentral Wisconsin

Adult Size:

20-35 inches

Description:

Round pupils

Distinctive upturned snout

Coloration and patterns are variable; typically brown, dark brown, or gray with dark-colored blotches, and may be patternless as adults. Typically have large dark patches on their necks, behind the head

Habitat:

Grasslands, savannas, prairies, and forests

Prefer habitats with sandy soil for burrowing

Diet:

Mostly amphibians, especially toads

Venomous/Non-Venomous:

Non-venomous

Eastern Milk Snake

Eastern Milk Snake close-up staring at you
There are 24 subspecies of milk snakes.

Scientific Name:

Lampropeltis triangulum

Range:

Southern 2/3rds of the state

Adult Size:

24-36 inches

Description:

Round pupils

Gray or light brown bodies with brown or rust-colored blotches outlined in black. Typically have a Y, U, or V-shaped marking behind the head

Habitat:

Savannas, prairies, pastures, hardwoods, and suburban areas

Diet:

Small mammals, lizards, other snakes, insects, amphibians, birds, and bird eggs

Venomous/Non-Venomous:

Non-venomous

Juvenile milk snakes are redder than adults, which leads people to mistake them for venomous copperheads. Fortunately, copperheads do not exist in Wisconsin.

Milk snakes are completely harmless and make great pets.

Iconic Wisconsin Snake Species

If you’re going out looking for snakes (“herping”), there are several must-see species.

I’ve selected some of the most iconic snakes found in Wisconsin.

Some of my personal favorites we’ve already discussed, so let’s take a look at a few new species.

Gopher Snake

If you come across an extra-long, heavily patterned snake, chances are it’s a bull snake in Wisconsin.

bull snake in the grass with its tongue out in a defensive position
Gopher Snakes are excellent burrowers and have a large scale on the tip of their nose to help them dig.

Bull snakes are a subspecies of gopher snakes. They inhabit prairies and savannas along the Western edge of the state.

This species of Special Concern is one of Wisconsin’s largest snakes. They average three to eight feet long!

Ribbon Snakes

Both Eastern and Western Ribbon snake species are endangered in Wisconsin. Habitat destruction, alteration, and pollution have contributed to their decline.

They have patchy distributions throughout the state and prefer habitats near water sources.

Western Ribbon Snake on top of rocks staring at you
The Western Ribbon Snake is the larger of the two species.

These are slender, long snakes with distinguishing lateral stripes.

Gray Rat Snake

The gray rate snake is another remarkably large snake found in Wisconsin, reaching over six feet long.

Gray Rat Snake around grass with its tongue out
The gray rat snake is a species of special concern in Wisconsin.
Image credit: Will Brown (via creativecommons.org

Rat snakes are adept climbers, often seen in trees where they consume birds and bird eggs.

Most rat snakes’ coloration changes as they age. Gray rat snakes are unique in the fact that they retain their juvenile coloration as adults.

Snakes Native to Wisconsin

Below is a comprehensive list of snakes found in Wisconsin, organized by family and genera.

Several species, like the North American (blue) racer, are the only representatives of their genus found in the state.

Colubridae

All but two snake species native to Wisconsin belong to the family Colubridae.

The Colubrids are a family of nonvenomous snakes found throughout the world. It’s the most extensive family of snakes and the most diverse.

Racers

North American (Blue) Racer

Coluber constrictor

King Snakes

Milk Snake

Lampropeltis triangulum

Worm Snakes

Western Worm Snake

Carphophis vermis

Green Snakes

Smooth Green Snake

Opheodrys vernalis

Lined Snakes

Lined Snake

Tropidoclonion lineatum

Watersnakes

Common Watersnake

Nerodia sipedon

Garter Snakes

Plains Gartersnake

Thamnophis radix

Butler’s Gartersnake

Thamnophis butleri

Eastern Ribbonsnake

Thamnophis sauritus

Western Ribbonsnake

Thamnophis proximus

Common Gartersnake

Thamnophis sirtalis

Gopher Snakes

Gopher Snake (Bullsnake)

Pituophis catenifer

Crayfish Snakes

Queensnake

Regina septemvittata

Hog-Nosed Snakes

Eastern Hog-Nosed Snake

Heterodon platirhinos

Ring-Necked Snakes

Prairie Ring-necked Snake

Diadophis punctatus arnyi

Northern Ring-necked Snake

Diadophis punctatus edwardsii

American Brown Snakes

Red-bellied Snake

Storeria occipitomaculata

DeKay’s Brownsnake

Storeria dekayi

Rat Snakes and Fox Snakes

Gray (Black) Ratsnake

Pantherophis spiloides

Eastern Foxsnake (Pine)

Pantherophis vulpinus

Viperidae

Rattlesnakes

Timber Rattlesnake

Crotalus horridus

Massasaugas

Eastern Massasauga

Sistrurus catenatus

Snakes in Northern Wisconsin

Because of its frigid climate, few snakes are able to tolerate living in Northern Wisconsin.

The only species you’ll find there are:

  • Red-bellied snake
  • Eastern fox snake
  • Smooth green snake
  • DeKay’s brownsnake
  • Common watersnake
  • Common garter snake
  • Eastern hognose snake
  • Northern ring-necked snake

There are NO venomous snakes in Northern Wisconsin.

What You Need to Know

Snakes aren’t out to get you.

They want to be left alone, and most of them will try to get away as quickly as possible if you get too close.

Some snakes rely on their excellent camouflage skills to avoid predators (you). Pit vipers are prone to staying as still as possible to hide in place, making it easier to step on them.

Besides the accidental misstep, the most common causes of snake bites are people attempting to handle, relocate, or injure a snake.

The wisest thing to do if you see a wild snake is to leave it alone.

Coexisting With Snakes

Seeing a snake around your home can be unsettling for many. I’m here to tell you, having these visitors is a good thing!

Snakes are essential components of the Wisconsin ecosystem.

Not only do they keep pest populations in check, but they also provide valuable food sources for other animals.

Species like the gopher snake famously prey on rodents. Others like the smooth green snake and ring-necked snake eat pesky insects and other invertebrates.

Their diets make them valuable allies to farmers, gardeners, and homeowners.

Snakes also help prevent the spread of disease by consuming sick animals or animals that host Lyme disease-carrying ticks.

Snake Safety

Venomous Snakes

There are only two venomous snakes in Wisconsin, and it’s unlikely that you’ll encounter either of them.

If you happen to meet one of them, the key is to give them their space.

Snakes primarily use their venom for subduing prey. They’ll typically use other defensive mechanisms to scare you off before resorting to biting.

Only one person has died from a venomous bite in Wisconsin since 1900.

Treading Carefully in Snake Habitat

There are several fundamental actions you can take to keep you and your loved ones safe while in potential snake habitats.

The most important steps:

  • Watch your footing
  • Stay on well-worn or paved paths
  • Wear sturdy shoes and long pants
  • Keep your pets on a leash and watch where they put their noses
  • Be cautious of where you put your hands, try not to reach where you can’t see them

Snakes like to hide under rocks, wood piles, debris, and in tall grass.

If You Encounter a Snake

If you come face to face with a snake, stay calm.

Snakes see you as a dangerous predator and want nothing to do with you.

The best thing to do is give it space.

You can observe it from a distance and let it move on.

If the snake is in an area that poses a threat to you or is in danger, contact a professional wildlife trapper.

When to Call for Help

Contact a trained wildlife professional for assistance removing snakes from your home.

If a venomous snake bites you, contact 911 immediately.

Antivenom is most effective when administered within a few hours, don’t wait for symptoms to appear.

Seek emergency veterinary care if a venomous snake bites your pet.

See the useful resources section below for a list of convenient contacts.

Useful Resources

Emergencies

Wisconsin Poison Center 800-815-8855

Free Snake Relocation Directory on Facebook

Animal Emergencies

American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center 888-426-4435

Pet Poison Hotline 800-213-6680

Additional Information

Wisconsin Rattlesnake Hotline 888-74SNAKE (888-747-6253)

Wisconsin Department of Natural Resources rattlesnake bite information

Share your snake observations with the Wisconsin Natural Heritage Inventory database

Articles Related to Wisconsin Snake Identification

If you enjoyed this Wisconsin identification guide, be sure to check out our other guides:

Looking for more information on snakes? We have a comprehensive collection of articles for all of your snake needs!

What’s your favorite Wisconsin snake species? Let us know in the comments!

Cheyenne Allen

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Cheyenne Allen is passionate about animals of all shapes and sizes. She has a bachelor's degree in Zoology with a concurrent major in Environment and Natural Resources. Cheyenne spent her summers doing field research in Wyoming during her college years. After graduating, she was a zookeeper for four years. These days she writes for ReptileGuide and has her own mini zoo at home, complete with a toddler.