Discover the 2 Types of Rattlesnakes in Illinois

Written by Kellianne Matthews
Updated: October 4, 2023
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Illinois has a wide range of diverse wildlife, including 38 different species of snakes. Unfortunately, 11 of these snake species are threatened or endangered in Illinois, primarily due to habitat loss and habitat alternation. However, another major threat to these snakes is human fear and violence. Snakes have a pretty bad reputation, and humans too often harm and kill them out of fear and misunderstanding. All snakes are extremely beneficial animals, and most of the snakes in Illinois are harmless. However, there are a few venomous snakes in the state, including two types of rattlesnakes.

What Types of Rattlesnakes are in Illinois?

There are only four types of venomous snakes in Illinois, all of which are pit vipers. This means that they have heat-sensitive pits on their faces that help them to detect prey. They also have large, triangular-shaped heads and elliptical pupils. Two of Illinois’ pit vipers are rattlesnakes: the eastern massasauga and the timber rattlesnake. Although these snakes are dangerous, most snake bites occur because the snake was stepped on or startled. It is important to be careful and try to stay away from rattlesnakes as much as possible. Be sure to always check before you sit down or step near rocks and logs, just in case there is a snake sleeping peacefully just out of sight.

Let’s take a closer look at the two types of rattlesnakes in Illinois and get a better understanding of these remarkable animals.

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1. Eastern Massasauga Rattlesnake

The eastern massasauga rattlesnake is one of three different subspecies of the massasauga rattlesnake.


Eastern Massasauga RattlesnakeStats
RangeScattered populations in Illinois
Length24 inches or less

The eastern massasauga rattlesnake is an endangered species in Illinois. It is illegal to hunt, kill, harm, or capture this snake. It is also a federally threatened species as well. The massasauga once lived in the northern 2/3 of Illinois, but most of its habitat has been lost due to agriculture and farming. In addition, the numbers of massasauga rattlesnakes in Illinois have decreased significantly due to the indiscriminate killing of these snakes by humans. In fact, according to a 2018 study, there may only be one population of massasauga rattlesnakes with only 100 snakes or less left in Illinois. Without intervention, it is predicted that the eastern massasauga will soon become extinct in Illinois.

The eastern massasauga rattlesnake is often called the “swamp rattler” because it often lives near water. These snakes frequently live in forested swamplands, prairie wetlands, lake edges, marshy grasslands, bogs, and wooded areas. They are a subspecies of massasauga rattlesnakes, growing to 24 inches in length at the most.

What Does the Eastern Massasauga Look Like? How Dangerous Is It?

Eastern massasaugas are gray snakes with dark gray or brown blotches shaped like “bow ties” running down their backs. Their scales are keeled with rough ridges. They also have dark blotches along their sides and dark stripes on either side of the face. Baby massasaugas look very similar to the adults, except that their tails are tipped with a bright yellow color.

Eastern massasauga rattlesnakes have cytotoxic venom that destroys tissue and prevents blood from clotting. However, these snakes are shy and docile, and it is extremely rare for an eastern massasauga to bite a human. These snakes try hard not to draw attention to themselves and rarely vibrate their rattles when humans are around. Eastern massasauga bites typically occur because the snake was accidently stepped on. These snakes primarily eat rodents, but they will also hunt frogs and small birds.

2. Timber Rattlesnake

Timber rattlesnaake coiled in a loop

These rattlesnakes like climbing trees up to 80 feet above the ground!

©Frode Jacobsen/

Timber RattlesnakeStats
RangeSouthern 1/3 of Illinois
Length36-60 inches

The timber rattlesnake is a threatened species in Illinois due to habitat loss and indiscriminate killing by humans. In fact, most timber rattlesnake deaths are caused by road vehicles or intentional human violence. Timber rattlesnakes live in the southern 1/3 of Illinois, often in counties along the Mississippi River border. They prefer habitats with rocky outcroppings, forested river bluffs, fields, edges of prairies, and forested areas along river and streams. Timber rattlesnakes are most active from April through October, often sunbathing on ledges and rocks, or climbing high in the trees. However, these snakes spend much of their time hiding in crevices in the ground.

What Does the Timber Rattlesnake Look Like? How dangerous Is It?

Timber rattlesnakes are one of the most dangerous snakes in North America. However, these snakes are not very aggressive, and it takes a lot to get one to strike. When it feels threatened, a timber rattlesnake will try to slither away and escape, or it will coil up and raise its head while rattling its tail in warning. These snakes will only bite as a last resort. Timber rattlesnakes eat birds and small rodents. On occasion, they may eat a toad or frog. These snakes have many natural predators, including coyotes, foxes, hawks, owls, and cats.

Timber rattlesnakes have gray, yellowish-brown, greenish-white, or yellow bodies measuring between 36-60 inches in length with a black-tipped tail. Some snakes are lighter in color, while others are so dark that they may look almost completely black. These snakes have keeled (ridged) scales that give their bodies a rough texture. They have 20-25 dark, jagged-shaped crossbands along their backs and bodies, with a rust-colored stripe running along the middle of their backs. Some timber rattlesnakes will also have a dark stripe behind each eye.

Other Snakes in Illinois

In addition to these two types of rattlesnakes, Illinois is also home to two additional pit vipers (the cottonmouth and copperhead), as well as 34 nonvenomous species of snakes. Even though these other nonvenomous snakes are completely harmless, many are often mistaken for venomous snake species because they have similar patterns and coloring. For example, the Eastern fox snake and water snakes are often mistaken for rattlesnakes and cottonmouth snakes, and brightly colored milk snakes have the same colors as dangerous coral snakes. Here are just a few examples of some of the snakes in Illinois that look dangerous, but actually are harmless and nonvenomous.

Eastern Fox Snake

Eastern Fox Snake (Pantherophis gloydi)

Fox snakes are agile climbers but tend to stay closer to the ground.

©Ryan M. Bolton/

Eastern Fox SnakeStats
RangeNorthern half of Illinois
Length36-54 inches

The eastern fox snake is a nonvenomous snake that lives in the northern half of Illinois. This snake is active during the day in prairies, woods, farmland, and pastures. The eastern fox snake is light brown or yellow with black or dark brown rectangular-shaped blotches along its back, as well as smaller dark blotches along the sides of its body. Its head is often brown or red without many markings. The snake’s belly is marked with a yellow and black checkerboard pattern. Eastern fox snakes are 36-54 inches long with mostly smooth scales. However, there are some slightly keeled scales with small ridges running along the middle of their backs.

Milk Snake

common red milksnake curled up

Beautiful milk snakes have a similar appearance to coral snakes.


Milk SnakeStats
RangeAll of Illinois
Length21-36 inches

Milk snakes have vivid red, black, and white markings, mimicking the appearance of the venomous coral snake. However, there are no coral snakes in Illinois, and milk snakes are not venomous and are completely harmless to humans. Milk snakes have smooth scales with red or reddish-brown bands or blotches along the length of their bodies, each outlined in black. White, cream, or gray markings or bands mark the spaces between these bands and blotches. Some snakes may also have a few blotches along their sides as well.

Snakes That Look Like Copperheads-Eastern Milk Snake

Eastern milk snakes are very beneficial animals, especially for farmers, as they hunt down small rodents.

©Jay Ondreicka/

There are two different subspecies of milk snakes in Illinois: the red milk snake and the eastern milk snake. Red milk snakes are found in the southern half of Illinois, growing between 21-28 inches in length. Eastern milk snakes, on the other hand, live in the northern half of Illinois and are 24-36 long.

Prairie Kingsnake

Prairie Kingsnake

The prairie kingsnake is sometimes called the yellow-bellied kingsnake.

©Matt Jeppson/

Prairie KingsnakeStats
RangeSouthern 2/3 of Illinois
Length30-42 inches

The prairie kingsnake lives in the southern 2/3 of Illinois. This snake has a smooth-scaled brown, gray, or tan body, measuring 30-42 inches in length. There are also red or brown blotches with black outlines covering its back and sides. The prairie kingsnake is a constrictor and eats other snakes, lizards, bird and turtle eggs, birds, and rodents.

Gray Rat Snake

gray rat snake

These rat snakes have checkerboard patterns on their bellies.


Gray Rat SnakeStats
RangeSouthern 2/3 of Illinois
Length42-72 inches

The gray rat snake also lives in the southern 2/3 of Illinois. This snake usually inhabits woodland areas, old fields, rocky hillsides, and farmland. It is a constrictor that eats small mammals, birds, and often climbs trees in search of prey. Gray rat snakes come in a range of colors but are often white, cream, tan, or gray, with large dark blotches running down their backs.

Water Snakes

Snakes That Look Like Copperheads-Northern Water Snake

Northern water snakes are sometimes confused with the venomous copperhead, which is rarely in water.


Water SnakeStats
RangeAll of Illinois
Length36-72 inches

There are five different species of water snakes in Illinois, with the northern water snake being the most common throughout the state. These snakes are generally between 3-6 feet in length with dark blotches along their bodies to help them blend into their surrounding environment. Unfortunately, these snakes are often killed because they can look like venomous cottonmouth snakes. However, water snakes are nonvenomous and harmless to humans (although they will bite if startled).

Water snakes are excellent swimmers and commonly inhabit reservoirs, lakes, ponds, streams, and marshes. Some like to hang from low tree branches and hunt just above the surface of the water for amphibians and fish. If you go boating in Illinois, but sure to stay away from areas with low branches to avoid having an unexpected snake land on your boat!

The photo featured at the top of this post is © Joe McDonald/

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About the Author

Kellianne Matthews is a writer at A-Z Animals where her primary focus is on anthrozoology, conservation, human-animal relationships, and animal behavior. Kellianne has been writing and researching animals for over ten years and has decades of hands-on experience working with a variety of different animals. She holds a Master’s Degree from Brigham Young University, which she earned in 2017. A resident of Utah, Kellianne enjoys creating, exploring and learning new things, analyzing movies, caring for animals, and playing with her cats.

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