confrontation – Discover-Nature

Venomous Snakes Of Illinois

There are 40 snake species native to Illinois, and they are found in all types of habitat from woodlands and prairies to wetlands and urban areas. Of these, four species are venomous. A venomous snake is one that uses a chemical toxin to kill its prey. This internally developed chemical is delivered through a pair of hollow fangs in the upper jaw of the mouth. When the snake opens its mouth, the fangs drop down and venom is injected into the prey as the snake bites. The snake will then release the prey, waiting for the venom to kill it before swallowing the prey whole. Juveniles will inject less venom, but with the same potency as adults.

^{Pit viper Fang and Jaw Structure drawn by M Moran at Encyclopedia Britannica}

Venomous snakes in Illinois are all pit vipers, a sub-family of the Viperidae family of snakes. The pit, a large opening between the eye and the nostril, just above the upper lip, can detect heat given off by warm-blooded prey species. Their elliptically-shaped eyes is another characteristic that helps to identify venomous snakes.

^{Close-up of elliptical eye on Copperhead by Mark Dumont, Jun 2011}

^{Close-up of pit above upper lip on pit vipers, by Scott Ballard, IDNR}

Illinois venomous snakes are non-aggressive in nature, but will bite if cornered, harassed, or stepped on. Bites are usually not fatal in humans, but they can be quite painful, often resulting in swelling and possible infection. Vomiting, nausea, and tissue or nerve damage may also result. Anyone that is bitten should seek immediate medical attention.

^{Eastern Copperhead, Agkistrodon contortrix, by Peter Paplanus, Aug 2018}

^{Eastern Copperhead close-up, Agkistrodon contortrix, by Peter Paplanus, Apr 2021}

The Eastern Copperhead, Agkistrodon contortrix, lives in the southern third of Illinois on wooded hillsides, river bluffs with sandstone or limestone outcroppings, and along forest edges. During the hot summer months, they may also feed on the abundant rodent populations in meadows or near abandoned buildings. The copperhead is about four feet in length and has a light brown back with one to two dozen reddish-brown colored hourglass-shaped markings along the back. The top of their head is a brighter red-brown.

^{Northern Cottonmouth, Agkistrodon piscivorus, by Virginia State Park Service, May 2016}

^{Northern Cottonmouth flashing white, Agkistrodon piscivorus, by Peter Paplanus, Aug 2022}

The Northern Cottonmouth, Agkistrodon piscivorus, resides in far southern parts of Illinois, living in swamps, sloughs, and oxbow lakes. At five feet in length, this heavy-bodied snake is a uniform charcoal or dark olive color, with dark crossbands and a tan to gray belly. When disturbed, its response is to face its attacker and open its mouth widely, displaying the bright white interior, earning the name of cottonmouth.

^{Timber rattlesnake close-up, Crotalus horridus, by Peter Paplanus, Apr 2023}

^{Timber rattlesnake, Crotalus horridus, by Peter Paplanus, Apr 2023}

Timber rattlesnakes, Crotalus horridus, live in both southern and northern areas along the Mississippi River and Illinois River valleys. Usually found in heavy timber with rock outcrops or bluffs, this snake, up to six feet long, is marked by two dozen black crossbars down a gray-green-yellow back. Its belly is light-colored with dark edges, and it shows a dark strip behind each eye. Timber rattlesnakes will hunt in any areas where there is a large rodent population. They are listed as threatened since we have seen sharp declines in the populations in recent years.

^{Massasauga Rattlesnake, Sistrurus catenatus, by Peter Paplanus, Apr 2021}

^{Massasauga Rattlesnake close-up, Sistrurus catenatus, by Peter Paplanus, Apr 2021}

The Massasauga Rattlesnake, Sistrurus catenatus, is found in small numbers scattered across the state, mainly in prairie wetlands and river floodplains. Listed as endangered in the United States, it has become quite rare in Illinois with only a couple sightings annually for the past several years. Massasaugas are about two feet in length, with a gray to light brown back and 30-40 dark, bow-tie shaped markings. Four to seven darker rings cover the tail. Their main prey is small rodents.

Venomous snakes have small ranges, staying close to home for hunting and mating. Their main predators include humans, birds of prey, and other snakes. Many have been killed by people with an unfounded fear of these creatures. Although they play a major role in controlling rodent populations, there has been little concern shown over loss of habitat due to draining of wetlands and other urban development. Plan a visit to the Jurica-Suchy Nature Museum or a nature center near you to learn more about these mysterious, yet wonderous species.

Snake Defense

Snakes, with over 3,000 species worldwide, are one of the largest groups of reptiles. They are found on every continent except Antarctica and live in every type of habitat including freshwater and saltwater. They have numerous enemies and have developed defensive strategies enabling them to survive and prosper.

^{Catching a snake on the wing by CuriousLog, Jun 2007}

^{Red-shouldered hawk with snake by Don Loarie, Mar 2018}

^{Great Blue Heron eating snake by C Watts, Jan 202}2

Snakes must deal with threats from a wide range of animals. Bird species that prey on snakes include raptors, ravens, egrets , and storks. Nocturnal hunters, including owls, have excellent sight in low-light conditions and often hunt by spotting movement among foliage. Likewise, during daytime hours, red-tailed hawks and eagles can spot movement on the ground while soaring. Snakes are normally line-of-sight hunters, and are often unaware of threats from above, giving avian predators a distinct advantage.

_{^{American crocodile, Crocodylus acutus by Florida Fish and Wildlife, Feb 2021; Wolverine by Maia C, Aug 2012; Skunk by D Fletcher, May 2016}}

Most mammal predators are larger, more agile, and faster. Badger, wolverine, and racoon are all excellent climbers and may hunt from an elevated perch. Wolverine and skunk are also burrowers that will dig out their prey from underground. Snakes living in saltwater and freshwater environments are eaten by predators such as crocodiles and snapping turtles. In addition, some larger snake species regularly hunt smaller snakes.

^{Copperhead on dead leaves by Abbott Handerson Thayer, Mar 2022}

Snakes use a number of non-aggressive strategies to avoid confrontation and escape. Their best defense is to remain hidden, using colors and patterns to break up the outline of their body, allowing the snake to blend with the background foliage and be overlooked by any predators. Another passive strategy is balling, involving compressing their body into a tight coil or ball, typically with the head tucked in to protect this most vulnerable area. Playing dead is often an effective means to escape predation, honed to perfection by the Western hognose snake. This snake convulses its body, rolls onto its back, and lets its tongue loll out of its mouth. It may vomit or spew blood, release fecal matter or musk, all in its attempt to convince a potential predator that it is already dead and no longer appetizing.

^{Timber rattlesnake balled and hidden by Peter Paplanus, Apr 2022}

Mimicry is a development that has taken place in some species over long periods of time. Batesian mimicry is when a harmless species has evolved the coloration of a more dangerous species to fool a predator into leaving it alone. Scarlet kingsnakes of the southeastern United States are quite harmless but look very much like Eastern coral snakes, a venomous species in that same area. Auditory mimicry involves creating sounds used by more dangerous snakes. Fox snakes, found in deciduous forests, often vibrate their tails in leaf litter, making a buzzing noise very similar to the sounds made by rattlesnakes living in the same area.

^{Scarlet kingsnake by FWC Fish & Wildlife Research Institute, May 2015}

^{Eastern coral snake by FWC Fish & Wildlife Research Institute, Sep 2014}

Snakes often use one or more methods of intimidation. Bright display colors are found among many venomous species and serve as a warning to potential predators that this snake is dangerous. Another form of intimidation involves a snake inflating its body or a body part to make it look bigger. The puff adder inflates its whole body by filling its lung with air. Cobras hold their heads high and flare out an extra fold of skin on either side of their heads, commonly called “hooding.” Intimidation may also involve auditory cues including the rattling of a snake’s tail and the hiss emitted by cobras as they bring up their heads.

When the above strategies do not allow the snake to escape, most species will not hesitate to strike. Several species do not bite, striking with the nose or an open mouth; however, all venomous snakes will bite in self-defense, although they may not inject venom. A few species are able to spit venom, used purely as an act of self-defense, although if the venom targets an eye or nasal passage, the results can be extremely painful.

Snakes are some of the most interesting species with a lifestyle very different from our own. They have many strategies for keeping themselves safe from wild predators, and will be around for us to observe, learn about, and be fascinated by.

Creepy Critters

A lot of creepy critters are starting to show up in my neighborhood as Halloween approaches. Many people are putting out scary pumpkins, bats, spiderwebs, and spiders. There are about 3,000 species of real spiders in North America, and all spiders have fangs that inject venom used to paralyze or kill their prey.

Spider web house by Stephanie Wallace, Oct 2007

Spiders are normally quite timid and must be threatened or provoked before they will attack a species larger than themselves. All spiders will bite, but most species do not have teeth that are large enough to break human skin. Of those that can bite through our skin, only four species dangerous to humans are found in North America. They belong to two groups, the widow spiders with three species in North America and the recluse spiders with eleven species in North America.

Widow spiders are all commonly called black widows, but they are actually three different species located across North America and include the western species, Lactrodectus hesperus, the northern species, Lactrodectus variolus, and the southern species, Lactrodectus mactans. In northern Illinois, the northern widow is a small species between 1/8″ and 3/8″ long. Males have long abdomens with white and red markings while females have more rounded abdomens with a red hourglass marking on their underside.

Northern black widow, *Lactrodectus variolus*, male by Judy Gallagher, May 2018

Northern black widow, *Lactrodectus variolus*, female by Andrew Hoffman, May 2012

Widow spiders are shy and tend to remain hidden under logs and stones, or just inside entrances to animal burrows. During autumn, as temperatures drop, they will move inside if possible and are often encountered under furniture, boxes, or discarded items that are not often disturbed. Webs are funnel-shaped and provide for adults and eggs. Once eggs are laid, the female will rarely leave the eggs untended, and will aggressively protect them from all harm, attempting to bite anyone that disturbs her or the eggs.

Black widows tend to flee rather than bite, unless they are protecting eggs. Only the females bite and their venom is especially dangerous to humans, but bites are not painful and may not even be noticeable at first. Severe stomach cramping develops within an hour or two and breathing may become difficult. Despite the uncomfortable effects, black widow bites are lethal in less than 1% of cases.

The brown recluse, Loxosceles reclusa, is the most widespread of the recluse spiders, and is often found in or around human dwellings. Other recluse species are found in very limited areas. Their favorite outdoor spots are under boards, stones and log piles, but they are most often found inside in quiet areas on the floor or behind furniture. Adult spiders are a light yellow-brown with a dark violin-shaped marking on their back. Adults are between 1/4″ and 1/2″ long with long, thin legs that can be three to four times the length of their body.

Brown recluse, *Loxosceles reclusa*, by Mike Keeling, Jan 2008

Recluse spiders are not aggressive and will only bite when disturbed. Most bites occur when the spider is caught in an article of clothing that is picked up off the floor, startling the spider. Once bitten, the wound develops a crust with a red zone around it. The crust may fall off rather quickly but leaves a crater behind that may take several months to fully heal. Although their bite may cause tissue damage, there have been no confirmed deaths in the United States.

Halloween is a special time of year and can be a fun time with scary creatures and other haunts. The Juricha-Suchy Nature Museum is hosting its 13th annual Creepy Critters Halloween Open House on October 26th (for info, please call (630) 829-6546 or email JuricaSuchyMuseum@ben.edu). I hope you get out for some trick-or-treating of your own, and let the real spiders live quietly in their own habitats.