The 3 Venomous Snakes of Southern Illinois


Have you ever been enjoying a peaceful hike and all the sudden you will hear something moving low and fast through the forest leaf litter?

Yeah, that’s a CREEPY feeling and one that I will never get used to, but for the most part we rarely see any of these elusive snakes.  When we do though for most of us our heart leaps into our throat and fear rushes in.

Watch Out for Snakes

We in Southern Illinois have very little to fear as we go for a hike.  Some places have bears and mountain lions (some say we do) that one must constantly be aware of.  Snakes or the fear of snakes is our one constant wildlife danger.

Most of these snakes we encounter on the trail are not of the venomous nature.  Even after 11 years of hiking on and off-trail I have ran into fewer than 10 venomous snakes.  All but for one (or actually a pair) have always been off the hiking trail.

It is more likely that you will run into several species of non-venomous snakes on the actual trail.  Some are just passing through, but others are using the trail as a place to get out of the deep forest and into the sun to warm up.

Before we go on just a note:  I am not a snake expert and am relying on my own personal experiences for this article.  Included in this article are links that will give you additional information.

1.  Copperhead


The copperhead is probably the most abundant venomous snake in Southern Illinois.  Their habitat is near wooded, rocky hillsides, and forest edges and can be found from Mississippi River to the Ohio River stretching the entire length of southern Illinois.

According to the Illinois Natural History Survey, this is how to idenitify:

  • Large (up to 135 cm TL), stout-bodied venomous snake. Back yellowish brown or rusty brown with 10-20 reddish brown hourglass-shaped, dark-margined crossbands that are narrow across the back and wider on the sides. Belly yellow to brown with brown blotches near the edges. Top of head red-brown. Thin dark line extends from eye to angle of jaw. The sulfur yellow tail tip of newborn darkens with maturity.

Copperheads can be easily confused with its non-venomous cousin, the Northern Watersnake, which is the most common snake seen around water edges.

2.  Cottonmouth


Also referred to as the water moccasin, this Southern Illinois snake has a far smaller range than the copperhead.  Its habitat is mainly around swamps, ox-bow lakes, and sloughs.

According to the Illinois Natural History Survey, this is how to idenitify:

  • Large (up to 159 cm TL), stout-bodied venomous snake. Juveniles and young adults have 12-18 dark crossbands on an olive or dark brown back and a dark stripe from snout through eye and upper lip. With age, adults become uniformly dark olive or black. Belly tan to gray and heavily marked with black. The sulfur yellow tail tip of newborn darkens with maturity.

Personally, I’ve only encountered these snakes at La-Rue Pine Hills, while off-trail hiking around the limestone bluffs (stupid thing to do).  Snake Road, also in Pine Hills is a notorious hot-spot for herpetologists  to observe snakes.

One distinct way to tell if you’re to close to this snake is that they will go into a defensive posture where they will throw their head back and open their mouth exposing the white, cotton-like underside.

This snake is, also confused with the non-venomous Northern Watersnake, because they can inhabit similar areas.  Occasionally than can be confused with the copperhead, which can be lighter in color.

3.  Timber Rattlesnake


Probably the most feared out of all the Southern Illinois snakes is Crotalus horridus or more commonly known as the Timber Rattlesnake.  This snake prefers the deep forest and thrives amongst rocky areas and around bluffs.

According to the Illinois Natural History Survey, this is how to idenitify:

  • Large (up to 180 cm TL), stout-bodied venomous snake. Back gray, light yellow, or greenish white with 20-25 black, jagged crossbars or blotches. Sometimes an orange or rust stripe down midback. Head clearly larger than slender neck. Dark stripe behind each eye. Tail tip uniformly black in adults. Belly pink, white, cream, or gray, with dark stippling toward sides.

The Timber Rattlesnake is unmistakeable.  The large head and the wide-body can send chills down the spine.  The rattlesnake has the unfortunate stigma as being aggressive, but this is primarily a myth retold to us by movies and books over the years, just as Jaws made us fear sharks.

According to

  • Timber rattlesnakes are surprisingly calm when encountered in the wild.  Many will sit motionless hoping that you will not see them.  If you do approach too closely, they may slither under a rock or into a crevice without rattling, unlike some other species of rattlesnakes which are more apt to stand their ground.


First, as if you didn’t already know, these snakes are dangerous and deadly.  Never provoke or handle any snake.  If you do encounter a snake on the trail the best action is to slowly move away always keeping your eyes on its location.

The best policy to avoid encounters is to constantly be on the lookout for snakes.  If you are with a group on a narrow trail and you are the one in the lead, it is your responsibility to be scanning.