Wisconsin is often seen as the Northwestern limit of multiple snake species found in Northeastern habitats across the US.
The state is home to a few established species as well as a few endangered snakes.
Are There Venomous Snakes in Wisconsin?
Only 2 snake species in Wisconsin are venomous. Timber Rattlesnakes and Eastern Massasauga are the highly venomous species still living in Wisconsin.
The bite of these snakes is highly dangerous to humans and it requires hospitalization.
Most other types of snakes in the state aren’t venomous. There are 5 species of Garter snakes in Wisconsin that can mimic rattlesnakes but which aren’t venomous.
Snakes live in dry habitats such as areas next to woodlands as well as in humid habitats such as marshes and areas near water across the state.
Snakes in Wisconsin
These are the venomous and non-venomous species still native to Wisconsin.
1. Common Garter Snake
A native species in Wisconsin, Common Garter Snakes (Thamnophis sirtalis) are a species identified by their 3 dorsal stripes.
Narrow yellow stripes are seen on this snake’s gray base color. A gray-to-brown coloring with additional dark spots is specific to this species.
Unlike Common Garter Snakes in Southern states, those in Wisconsin don’t exhibit a gray color with blue undertones.
Common Garter Snakes are also perceived as a common snake species in the state through their numerous presence in suburban areas.
There are 5 species of garter snakes in Wisconsin. Common Garter Snakes are the most common garter snakes in the state. Other species are only found in remote Southern or Eastern parts of the state.
Snakes of this species aren’t protected in the state, even if they enjoy a protected status in other states.
Common Garter Snakes live in almost any type of dry habitat as long as there’s vegetation to hide under. They can also hide under rocks and logs.
This species is diurnal and active every month, including during the winter. Common Garter Snakes only hide on cold winter days and come out on sunny winter days.
This species has a diverse diet that includes tadpoles, frogs, slugs, and even fish.
Most Common Garter Snakes in the state grow up to a size of 22-26 inches with some of the largest examples of the species measuring 46 inches.
2. Common Watersnake
Common Watersnakes (Nerodia sipedon) can be brown, gray, or red-brown with blotches. The dark blotches on the species and its aquatic habitat often confuse the species with venomous cottonmouths.
As its name suggests, this is a species only found next to water or in areas of very high humidity. Canals, streams, rivers, and ponds are water bodies attracting the species across the state.
Common Watersnakes may be longer than Common Garter snakes as they can grow longer than 4 feet.
The number of Common Watersnakes is stable across the state. While both Common Garter Snakes and Common Watersnakes are endangered in other states, these are common species in Wisconsin.
You can identify this snake species by its wide long body which can measure more than 50 inches.
Most snakes in the state are shorter, however. Square brown or red-brown blotches are spotted on the species.
These blotches can also appear black on some snakes.
Common Watersnakes aren’t docile and don’t like being handled. While not venomous, the snake bites multiple times.
It can bite when cornered or when handled. Common Watersnakes aren’t docile and don’t like being handled. While not venomous, the snake bites multiple times.
It can bite when cornered or when handled.
Common Watersnakes also possess other defensive techniques such as releasing excrement when handled.
3. Red-bellied Snake
Red-bellied Snakes (Storeria occipitomaculata) have 2 distinct coloring traits that set them apart from other species. A red underbelly is specific to this species.
Most Red-bellied Snakes also have a secondary trait in the form of a light brown band behind the back.
The red underbelly of the Red-bellied Snake shows uniform coloring.
While common, the Red-bellied Snake isn’t easily spotted as the species is fossorial.
Much of its life is spent underground which means the snake also has small in size. Many Red-bellied Snakes measure 6-8 inches, with the largest specimen measuring up to 10 inches.
This species is small and non-threatening. It doesn’t bite either.
While handled, the species has a type of death-mimicry tactic where it stays still and bites its lips.
This species may sometimes be encountered in the breeding season, which is normally the beginning of the summer.
Female Red-bellied Snakes give birth to live young snakes.
The number of born snakes varies from female to female. Once they reach sexual maturity, females can give birth to a group of up to 9 snakes.
Young Red-bellied Snakes have a bright brown uniform color, unlike adults. They can sometimes be mistaken for earthworms.
4. Eastern Foxsnake
Eastern Foxsnakes (Pantherophis vulpinus) are among the typical snakes you can find around Wisconsin farms. Both active farms and old farms attract these snakes, mainly through prey.
Rodents such as rats are part of the diet of these snakes.
Unlike most other species in the state, Eastern Foxsnakes are constrictors. They suffocate prey before swallowing it.
Other types of prey such as frogs are also common for the species.
Some other typical traits of this species include the ability to release a foul smell when under threat.
This smell has been compared to the smell of wet foxes and has also inspired its name.
Surviving up to a few years, these snakes are often seen in the sun in open fields in the summer.
They move underground during the winter.
Prairies and other open fields may attract these snakes on the warmest winter days when they come out for the sun’s heat.
The mating season of the species is a good time to spot these snakes.
A period between May and June marks the mating period of Eastern Foxsnakes and also a time when males are seen fighting each other.
Males of the species fight for mating rights.
5. Dekay’s Brownsnake
A small body is specific to Dekay’s Brownsankes (Storeria dekayi). This common species is often seen in a size that barely measures more than 10 inches.
A brown color is specific to the snake. Gray and dark brown colors are also specific to this species.
A non-venomous snake, Dekay’s Brownsnake is a species found next to the water and in dry habitats at different elevations.
The species is even found at altitudes of over 4.000 feet.
Its reduced size also limits the prey Dekay’s Brownsnakes can consume.
Snails are its most important type of food.
The snake that rarely grows a length of over 12 inches is also a common prey to other predators of the ecosystem given it has a reduced size.
Toads are some of the most common predators of snakes, especially of young Dekay’s Brownsnakes.
Confused with earthworms in their early days, this snake is sometimes spotted eating earthworms themselves.
It can be handled as it has a docile nature and a non-venomous bite.
6. Eastern Hognose Snake
By venom alone, the Eastern Hognose Snake (Heterodon platirhinos) is the most widespread mildly-venomous species in Wisconsin.
This is a snake that only has venomous saliva, but this saliva doesn’t affect humans, in case of a bite.
This snake rarely bites humans as it gives off warning signs first. It raises its head above the ground, similar to a cobra before biting.
Eastern Hognose Snakes have venomous saliva which affects prey such as toads, one of its most common types of prey.
Even poisonous toads can be consumed by this snake which is immune to its secretions.
This snake comes in different colors which depend on its morphs as well as its regions.
The snake can have a black color outside of the state and a colorful patterned body with orange-red marks behind its head in Wisconsin.
Brown is the main color of the species. However, its dorsal coloring differs.
It can show blotches or uniform dorsal color.
Since it feeds on toads, this snake is largely found in areas where toads live. This includes humid areas and habitats in the proximity of water.
The loose ground is something this snake prefers. Females use the loose ground to lay eggs in as well.
7. Eastern Milksnake
Most central and Southern parts of Wisconsin are habitats to the Eastern Milksnake (Lampropeltis triangulum).
This is a species with considerable color variations depending on its region. A gray-brown color with dark brown blotches that feature black edges is specific to its Wisconsin morph.
Native to Eastern and Central parts of the US, this snake has expanded its reach West to Wisconsin and Ohio, in a darker dominant morph.
Prairies and pastures are among the common habitats where this snake easily blends in.
Eastern Milksnakes are a common sight on grounds with rodents and rodent burrows. They sometimes hide in rodent burrows themselves.
Eastern Milksnakes are wrongly associated with drinking milk. This species prefers a diet based on rodents.
A generally docile species, the snake may attempt to bite. Its bites are uneventful for humans as the snake is non-venomous.
The highest probability of seeing this snake is around farms in the summer. It’s here rodents come to eat various grains and foods and snakes follow shortly.
8. Smooth Greensnake
Smooth Greensnakes (Opheodrys vernalis) are the most common green snakes in the state. A vivid uniform green color is specific to this snake.
Its size can vary according to its age but it’s rarely larger than 20 inches. Some of the smallest adult Smooth Greensnakes only measure 14 inches.
This species relies on its green coloring to hide in areas with dense vegetation.
It raises its head above short vegetation to locate its prey. This snake has even adapted to moving its head with the wind so that it maintains its camouflage in front of possible prey.
The small size of the snake and its slender body limit the type of food it can consume.
Insects and bugs are their typical prey, together with arachnids such as spiders.
In turn, the small Smooth Greensnake is also seen as prey for other species, particularly predatory birds.
Hawks are among the most successful Smooth Greensnake predators.
Seeing this snake is not a rare event as it has a diurnal and a nocturnal nature in the summer.
A species that hibernates, the Smooth Greensnake moves underground in the winter.
It hibernates in the ground together with other snakes of its species.
9. Gopher Snake
Gopher Snakes (Pituophis catenifer) are a common gray-to-brown with dark brown patches species.
The yellow base color with brown blotches is also specific to this snake.
Gopher Snakes use different biting methods that make them stand out.
This is a snake species that mimics a bite using the same techniques of tail-shaking similar to rattlesnakes.
Gopher Snakes are a species that relies on constriction to kill its prey. This prey includes other small snakes as well as small birds.
The species is also a victim of other predatory species such as foxes, particularly in its early days.
A Gopher Snake can live up to 15 years in a habitat with plenty of food.
Non-venomous Gopher snakes can bite humans if cornered. Their bite is painful but not followed by venom injection.
Snakes of this genus are also known for having a positive role in the ecosystem as they help reduce rodent populations where it matters, mostly on crops and farms.
Gopher Snakes have stable populations across Wisconsin. Humans are among their most common predators killing them when wrongly mistaken for rattlesnakes.
10. Prairie Ringneck Snake
A yellow neckband helps identify the Prairie Ringneck Snake (Diadophis punctatus arnyi).
This is one of the smallest snakes in Wisconsin and a known constrictor. Prairies Ringneck Snakes use constriction against small prey such as lizards.
Occasionally, the Prairie Ringneck Snake also constricts small rodents such as mice.
This species is among the few with a multicolored ventral side.
Most snakes have only one underbelly color but Prairie Ringneck Snakes have 3 ventral colors.
Yellow is the dominant color, covering more than half of the ventral side of this species.
Orange and red colors are seen in lesser proportions on its underbelly.
These colors help the snake keep predators away as it rolls over to play dead in face of a potential threat.
While small and non-venomous, Prairie Ringneck Snake has bitten people a few times.
This is a non-venomous snake with venomous saliva which helps it overpower some of the smaller prey it goes after.
A common sight on prairies, this species may be seen in the summer.
It prefers to come out of its hiding spots to bask in the sun for warmth.
11. Northern Ringneck Snake
Northern Ringneck Snakes (Diadophis punctatus edwardsii) are another native Wisconsin species with a reduced size found almost everywhere in the state.
With a preference towards moist habitats, this is a species that can be found underground or next to the water.
It has a black color and a yellow ringneck inspiring its name.
Northern Ringneck snakes are some of the most predated species in the state. Toads are some of the most common predators of the species as they share the same habitat.
This snake species may be found around woodlands, particularly at the edges of woodlands. These are naturally moist habitats with plenty of food and shelter.
Overwintering also takes place in moist habitats. These snakes may take refuge in rodent burrows to hide during the winter.
Cool damp places such as basements may also attract Northern Ringneck snakes looking to overwinter.
One of the easiest moments to spot the snake around woodlands is during the summer when it chases salamander.
The mating season is also a good time to spot the species.
Female Northern Ringneck snakes lay up to 10 eggs in loose soil.
12. Butler’s Garter Snake
Butler’s Garter Snakes (Thamnophis butleri) are one of the 5 species of garter snakes native to Wisconsin.
This means the species has 3 yellow dorsal stripes to set itself apart.
These stripes are normally yellow but they may also be orange in rare cases.
Open areas with vegetation and moisture are known to attract the species. Prairies, the edges of woodlands, and marshes are among the areas where this snake is common.
It’s here that it can find some of its favorite prey which also favors high moisture. Salamander is among the preferred prey for Butler’s Garter Snakes.
Small frogs are also consumed by this snake which may also eat medium-sized frogs if it grows larger.
Butler’s Garter Snakes are small to medium-sized themselves. They often reach a length of over 20 inches.
Even newborn Butler’s Garter Snakes measure at least 5 inches.
Young snakes are born at the beginning of the summer. These young Butler’s Garter Snakes are born in groups.
Wisconsin is one of the states where Butler’s Garter Snakes still have stable populations with broods of up to 14 young snakes per sexually mature female.
Other states list this species as a concern due to its diminishing natural habitat.
13. Plains Garter Snake
Plains Garter Snakes (Thamnophis radix) are one of the 5 Wisconsin native garter snakes.
They feature a combination of yellow and orange dorsal stripes which contrast a gray or a dark green body.
This species exists in hibernation in April when the snake exists in its hiding spots. Some of its overwintering spots include man-made buildings and rodent burrows.
It starts to breed immediately after coming out again. The young Plains Garter Snakes are only born at the end of the summer or in the fall.
Growing to a size of up to 4 feet, Wisconsin Plains Garter Snakes may be found in short vegetation during the summer.
It’s here that the snake looks for salamanders and earthworms. On occasion, The Plains Garter Snake can also eat small frogs or young toads.
It remains an active species towards the end of the summer. The species enter hibernation in October with very rare sights specific during the winter months.
Plains Garter Snakes enjoy stable populations across Wisconsin. High adaptability is specific to this species.
One of its distinct adaptability traits includes the capacity to live at high altitudes.
While Wisconsin only has a maximum elevation of 1.900 feet, Plains Garter Snakes have been found even at 7.000 feet.
14. Timber Rattlesnake
Timber Rattlesnakes (Crotalus horridus) are the most common venomous species in Wisconsin. These snakes are abundant in the Northeastern regions of the United States and the Southwestern regions of Wisconsin.
Timber Rattlesnakes have a gray or yellow-brown base color with black crossbands.
You can identify the species further by its keeled scales. The rough-touch scales of the Timber Rattlesnake have a central ridge.
This is one of the species that grows past the 60-inch mark, meaning it’s also a large snake in the state.
Medical attention is needed following a Timber Rattlesnake bite.
As one of the most venomous snakes in North America, Timber Rattlesnakes are known for their neurotoxic venom.
Females are also known to be aggressive before giving birth. They might be found resting on a warm rock sitting out in the sun.
Male and female locations can differ in the summer. Males prefer to hide in vegetation in a shaded spot while female Timber Rattlesnakes may be found in open areas with plenty of sunlight.
Both males and females live long. They can survive nearly 10 years in the wilderness.
Male and female Timber Rattlesnakes choose limestone crevices as overwintering spots.
15. North American Racer
North American Racers (Coluber constrictor) are mid-sized to large snakes that are common in Wisconsin.
While large, this snake species is non-venomous. These snakes are characterized by a base black color.
These snakes aren’t always black. A young North American Racer snake is mainly gray with brown blotches.
Multiple types of dry and humid habitats are the home to the species.
Areas around woodlands, including cypress woodlands, are home to the species.
North American Racer snakes are further known to be a docile species.
Handling the snakes isn’t recommended as they can bite when provoked.
Both adult and juvenile North American Racers are known to bite. The first reaction of the snake is to flee and it might only bite if handled or roughly handled.
The bite itself is painful given its size, but not dangerous to humans.
A diverse diet is specific to this snake, given it has the size to eat rodents. It also eats lizards, frogs, and salamanders in woodlands.
Fish is also part of the snake’s diet.
These snakes swallow their prey alive.
Mating is specific to warm weather months in the state. Female North American Racer snakes lay eggs in the ground.
Up to 16 eggs are laid by a single female after mating.
16. Gray Ratsnake
Gray Ratsnakes (Pantherophis spiloides) are now a rare sight in Wisconsin. This native snake species is seen as a species that used to be common in Wisconsin and nearby states.
Still found around woodlands, Gray Ratsnakes are known to climb.
They can be spotted on the ground or climbing up trees. They might be interested in climbing trees either to escape a potential predator or to look for food.
Birds and bird eggs are among its favorite reasons to climb trees.
Gray Ratsnakes are further known for staying still when spotting humans.
It will not try to escape as the snake holds its ground in front of people.
Gray Ratsnakes also try different techniques to make people and predators go away such as rattling its tail on the ground.
These snakes can also raise their head to make it look like they’re about to bite.
The snake is an avid hunter. It uses scent to detect potential prey and takes advantage of its large body to suffocate its small mammal prey.
This Gray Snake is one of the largest species in Wisconsin. Most grow to a size of up to 6 feet with some of the largest snakes of the family growing to 8 feet.
17. Western Foxsnake
This snake species (Pantherophis ramspotti) has a base gray color with dark brown or black blotches.
Like the Gray Ratsnake, Western Foxsnakes are constrictors. They suffocate prey such as rodents and rabbits first.
These snakes are found on abandoned farmland, next to woodlands, and next to water sources.
Western Foxsankes may also live close to humans.
Like other snakes in Wisconsin, Western Foxsnakes may appear venomous. The species has a gray color and it rattles its tail similarly to rattlesnakes.
This makes some people assume the species is venomous.
An adaptable species even in disturbed habitats such as active farmland, the species is still seen in low numbers across the state.
While it lives next to human settlements, it tends to shy away when its habitat is confronted with intense human activity.
Western Foxsnake can travel considerable distances for food and may attempt to approach suburban areas for prey.
18. Eastern Massasauga
A venomous snake species, Eastern Massasaugas (Sistrurus catenatus) are snakes found in the Southwestern regions of the state.
These snakes live in shallow wetlands and marshes.
Eastern Massasauga snakes are an endangered species in Wisconsin.
The venomous nature of this pit viper makes many people kill it which means its facing extinction in its small Wisconsin habitat.
Its potent venom makes most people stay away.
Prairies and wetlands this species can be still spotted on are areas of its habitat rich in small mammal prey.
It eats mice, rats, and shrews. Small reptiles and even small snakes can be eaten by the Eastern Massasauga.
19. Eastern Ribbonsnake
Named after the stripes on their dorsal side, Eastern Ribbonsnakes (Thamnophis sauritus) are among the species known for their clod-blooded prey diet.
These types of snakes don’t eat mammals. They prefer salamanders, frogs, toads, and fish.
A non-venomous species, the Eastern Ribbonsnake is ovoviviparous.
Up to 27 live young snakes are born from each mated female.
This number can be considerably smaller in Wisconsin. Furthermore, the Eastern Ribbonsanke female takes up to 3 years to sexually mature and start mating.
Queensnakes (Regina septemvittata) are some of the native species of Wisconsin often confused with Garter Snakes.
This species also has a dark olive-green color and yellow stripes like the 5 species of Garter Snakes in Wisconsin.
However, these yellow stripes are only seen on the ventral side of the snake.
Queensnakes are some of the pickiest species in the state as they need very specific clean water conditions to survive.
This is the only type of water that favors newly-molted crayfish, the main prey of the snake.
21. Lined Snake
This yellow-striped snake (Tropidoclonion lineatum) is among the species in Wisconsin that spends much of its life underground.
A partly fossorial species, Lined Snakes live underground where they survive on earthworms.
The end of the summer marks the year when this species may be most common in.
Females give birth to live young in August.
Up to 8 young Lined Snakes are born from females each summer.
22. Western Ribbonsnake
Western Ribbonsnakes (Thamnophis proximus) are only found in Southern areas of Wisconsin.
They prefer areas around streams and rivers.
These snakes are active from March each year. They remain active until October.
Western Ribbonsnakes is a species that breeds in late spring or early summer.
This striped species then disappears in common dens where it overwinters with other species rarely coming out until next the next spring.
23. Western Wormsnake
Only territories in extreme Southwest Wisconsin are suitable for non-venomous Western Wormsnakes (Carphophis vermis).
This rare species lives elusive lives underground.
Western Wormsnakes are identified by their small body and pink ventral color.
The name of the species is inspired by the worms and insects’ diet of the species.
Found in loose soil, this species is known to lay eggs at the beginning of the summer.
Female Western Wormsnakes lay clutches of up to 8 eggs.