There are 40 different species of snakes in Missouri. Of these, there are 6 species of venomous snakes. We will go into these types of venomous snakes and where to find them in Missouri.
- Eastern Copperhead (Agkistrodon contortrix)
- Northern Cottonmouth (Agkistrodon piscivorus)
- Timber Rattlesnake (Crotalus horridus)
- Western Pygmy Rattlesnake (Sistrurus m. streckeri)
- Eastern Massasauga Rattlesnake (Sistrurus catenatus)
- Western Massasauga Rattlesnake (Sistrurus tergeminus)
Pit Vipers
Copperheads, Cottonmouths, and Rattlesnakes belong to the venomous Crotalinae or pit viper family. Pit vipers have a deep facial pit between their nostril and eyes on each side of their face. These pits are actually specialized organs that detect infrared radiation from prey animals. Pit organs enable pit vipers to strike their prey precisely, even in the dark. They are also able to detect body heat from about 1 meter away.
These snakes also have triangular-shaped heads. Furthermore, the pupils of their eyes are vertical slits.
Pit vipers have hollow fangs connected to venom glands. They use their fangs to inject venom into their prey. This venom immobilizes the prey, making it easier for the snake to consume. They primarily consume small mammals, reptiles, amphibians, small birds, and large insects. These snakes play an important role in maintaining balance in rodent populations.
Eastern Copperhead
| Scientific Name: | Agkistrodon contortrix |
| Description: | Adult copperheads are 20 to 37 inches (50 to 95 cm) long. Their bodies are coppery brown overlayed with dark brown hourglass blotches. |
| Habitat: | Deciduous forests, river bottoms, and rocky wooded hillsides. |
| Conservation Status: | It is one of the most common venomous snakes in Missouri. Found throughout the state. |
The Eastern Copperhead is a pit viper native to the eastern United States. Missouri was formerly home to the Osage Copperhead subspecies. However, DNA analysis shows little genetic difference between the two. Today the former Northern Copperhead, Southern Copperhead, and Osage Copperhead are taxonomically combined. The common name for these snakes is Eastern Copperhead. Their scientific name is Agkistrodon contortrix. Source
Eastern Copperhead snakes have reddish-tan to grayish-tan bodies. Their bodies are overlaid with hourglass-shaped dark brown markings. Their triangular heads are proportionately large. The color of their head is dark coppery brown. This is the reason they have the name “Copperhead.”
Copperheads are stout heavy-bodied snakes. Adult copperheads are 20 to 37 inches (50 to 95 cm) long.
Where Do Eastern Copperheads Live in Missouri?
The Eastern Copperhead is the most common venomous snake in Missouri. They are found statewide, with the exception of the northern border.
These snakes are found in rocky wooded areas and river bottoms. Copperheads occasionally make their way into urban areas as they follow waterways. They reside where leaf and plant debris or tall grass provide cover for them to hide. Source
Eastern Copperhead Behavior
Copperheads use their camouflage as their number one defense mechanism. This makes them dangerous. These snakes choose to lie perfectly still rather than flee most of the time. Their camouflage helps them blend in with leaf litter and other ground debris.
When they feel threatened, they occasionally mimic the tail vibration of a rattlesnake. However, in the majority of instances, they opt to remain completely motionless.
Most copperhead bites on humans occur when the person steps on or near the snake.
Wintertime Brumation
Snakes do not tolerate cold winters very well. They are ectotherms, which means they cannot regulate their body temperature internally. Physiologically, ectotherms cannot hibernate. Yet, they go into a state of suspended animation called brumation for up to 6 months out of the year.
Copperheads winter underneath rocks, in hollow logs, and in fissures on rocky hillsides. An individual might brumate alone in some parts of their range. But copperheads tend to be social. In some areas, they congregate together in dens with other snakes through the winter.
In hilly terrain, south-facing slopes capture more radiant warmth from the sun. So, that is where these dens are generally located. The other snakes they den with are not necessarily just copperheads. Sometimes, they share their dens with other species of snakes. You may find a Timber Rattler, a Southern Black Racer, or a Black Rat Snake sharing the same den with copperheads. These wintertime dens may hold up to 60 snakes.
What Do Copperheads Eat?
Copperhead snakes are opportunistic feeders. They eat insects, spiders, frogs, small animals, birds, and other reptiles.
How Dangerous Are Copperheads?
A Copperhead can bite and inject venom from the time they are newly born. Like most pit vipers, they have hemotoxic venom.
Most copperhead bites are not life-threatening. On the other hand, any bite from this snake is a medical emergency and should be treated as such. Prompt medical attention increases the chance of a good outcome.
Copperhead bites can cause intense pain, shock, and swelling. Their bites also have the potential to cause blood in urine, tissue damage, and kidney failure.
An interesting study has found that Copperhead venom contains a protein called contortrostatin. Contortrostatin has been found to stop the growth of cancer cells in mice.
Northern Cottonmouth
| Scientific Name: | Agkistrodon piscivorus |
| Description: | Adult cottonmouths are stout, muscular snakes that grow up to 3 ft (.91m) long. Their body is dark brown with few markings. Their mouth is “cottony” white. |
| Habitat: | These snakes live near water sources like swamps, marshes, rivers, and lakes. |
| Conservation Status: | Common within their range in Missouri. |
Another common name for the Northern Cottonmouth snake is water moccasin. These are stout, muscular snakes that grow up to 3 feet (.91m) long. They look a little bit like rattlesnakes without the rattle on the tail. It is also easy to mistake one for a common water snake. This could be a dangerous mistake.
The Northern Cottonmouth has a dark brown to black body with few markings. The inside of their mouth is white, hence the name “cottonmouth.” When threatened, they will pose with their mouth open. They have cat-like pupils, which appear as narrow slits in the day, and at night, they have a round appearance.
The juvenile cottonmouth has a more clearly defined pattern than adults. Their patterning resembles that of a copperhead snake. They have darker bands, though, that widen toward the belly and narrow at the back.
Where Do Northern Cottonmouths Live in Missouri?
The southern Ozarks and the wetlands of Southeast Missouri are home to these snakes. They spend most of their time near swamps, marshes, rivers, and lakes. They can hold their breath underwater for up to an hour while hunting for prey.
What Do Northern Cottonmouths Eat?
These snakes prey on fish, freshwater crustaceans, amphibians, small rodents, and other reptiles. Cottonmouths sometimes congregate around drying wetland pools to feed on any trapped fish.
How Dangerous Are Northern Cottonmouths?
Cottonmouth snake venom is cytotoxic. This means it destroys body tissue. Northern Cottonmouth bites sometimes lead to the amputation of limbs. On rare occasions, death can occur. See
Rattlesnakes
The first thing people think about concerning rattlesnakes is their tails. When they are disturbed, they vibrate the rattles on their tails. This makes a buzzing or a rattling-type sound. Beware though. Sometimes, rattlers strike without rattling. Sometimes, their rattles fall off. You must be aware of where you are placing your hands and feet when you’re in rattlesnake country. If you hear a rattling noise, don’t move until you spot where it originated. Otherwise, you may accidentally move into the snake, prompting it to strike you.
Timber Rattlesnake
| Scientific Name: | Crotalus horridus |
| Description: | Adult Timber Rattlesnakes grow between 36 and 60 inches (.91 to 1.52m) long. Their bodies are yellowish-brown with a dark chevron pattern. They also have a rusty stripe down their backs. Their tails are dark brown or black. |
| Habitat: | Timber Rattlesnakes prefer wooded areas and hillsides with rocky outcroppings. |
| Conservation status: | It is one of the most common venomous snakes in Missouri. |
Timber Rattler and Canebrake Rattlesnake are both common names for the Timber Rattlesnake. Generally, in higher-elevation habitats, they are called Timber Rattlesnakes. In lowland areas, though, they’re called Canebrake Rattlesnakes.
The Timber Rattlesnake is Missouri’s largest venomous snake. The average adult grows from 36 to 60 inches (.91 to 1.52m) long. However, there have been reports of them growing up to 7 feet (2.13m) long. See
These snakes vary in color. Their general base coloration is a yellowish-brown to grey-brown, though. They have a dark brown to black chevron pattern on their back and sides against a lighter base color. Moreover, they have a rusty to reddish stripe down their backs. Their tails are dark brown or black. There are also melanistic timber rattlers. These are dark and sometimes almost entirely black. In the dark color morph of these snakes, the tail is also darker than the rest of the snake’s body.
Where Do Timber Rattlesnakes Live in Missouri?
The Timber Rattlesnake is the most common venomous snake in Missouri. They are found throughout the state. Timber Rattlers live in various habitats. These include wooded areas, swamps, farm fields, and river floodplains.
What Do Timber Rattlesnakes Eat?
Timber rattlers prey on small mammals such as mice, rats, squirrels, and chipmunks. They also eat small birds, other reptiles, and amphibians.
These snakes are excellent climbers. In fact, timber rattlers have been found in trees at heights of more than 80 feet. Source
Experts have proven that timber rattlesnakes help control Lyme disease. This is because as they consume rodents, they’re also consuming ticks. A timber rattler will consume 2,500 to 4,500 ticks per year, depending on the location. See
Wintertime Brumation
Snakes do not tolerate the cold weather in the winter months very well. They are ectotherms, which means they can not regulate their body temperature internally. Physiologically, ectotherms cannot hibernate. Yet, they go into a state of suspended animation called brumation for up to 6 months out of the year.
Timber Rattlesnakes make wintertime dens in sheltered spots. They den underneath rocks and logs, as well as in fissures in rocky hillsides. An individual Timber Rattler might brumate alone in some parts of their range. But in other areas, they congregate in dens with other snakes through the winter.
Dens are usually placed on slopes facing south because they get more warmth from the sun. They don’t always share their dens only with Timber Rattlers. Sometimes, they share their dens with other species of snakes. These might include Copperheads, Black Rat Snakes, and Eastern Black Racers. These wintertime dens may hold up to 60 snakes.
How Dangerous Are Timber Rattlesnakes?
Timber Rattlesnakes are among the most dangerous in the United States. This is due to their long fangs and high venom yield. 1% to 10% of untreated Timber Rattlesnake bites result in a fatality.
Fortunately, 40% to 60% of the time, they produce dry bites. In other words, although their fangs penetrate the body, they do not inject any venom. Source
These snakes produce hemotoxic venom. Timber Rattlesnake bites sometimes cause serious complications. These include shock, seizures, coma, internal bleeding, and deep tissue damage. Source
Also see: Scorpions in Missouri – Krebs Creek
Wild Cats in Missouri – Krebs Creek
Bears in Missouri – Krebs Creek
Are There Elk in Missouri? – Krebs Creek
Western Pygmy Rattlesnake
| Scientific Name: | Sistrurus m. streckeri |
| Description: | Adult Western pygmies are 16 to 25 inches (.41 to .64m) long. Their bodies are light gray overlayed with dark blotches. A rust-colored stripe runs along its spine. |
| Habitat: | They inhabit sandhills, mixed forests, and floodplains. They also tend to be in close proximity to marshes, lakes, and other water sources. |
| Conservation Status: | Common within their range in Missouri. |
The Western Pygmy Rattlesnake is a small, slender-tailed snake with a tiny rattle. It grows in length between 16 to 25 inches (.41 to .64m). The base color of its body is light gray. Furthermore, they have a rust-colored stripe along their spine. (The stripe may be absent in some individuals.) They also have a series of dark-colored blotches along their top and sides. Their cream-colored bellies are frequently mottled. They have a distinct, dark stripe that leads from the corner of their mouth to their eye. Their tiny rattle makes a faint grasshopper-like buzz that can only be heard from a yard away.
Where Do Western Pygmy Rattlesnakes Live in Missouri?
Western Pygmy Rattlesnakes live in southwest and south-central Missouri. They prefer sandhills, mixed forests, and floodplains near aquatic environments. They are rarely found in extremely dry habitats. Source
Other common names for this snake are ground rattlesnake and pygmy rattlesnake.
How Dangerous Are Western Pygmy Rattlesnakes?
Western Pygmy rattlesnakes have cytotoxic venom. By definition, cytotoxic venom destroys the body’s cells. This venom disrupts blood flow and prevents clotting with its digestive enzymes. Luckily, these snakes produce a small venom yield. A bite from a pygmy rattlesnake is unlikely to be fatal. However, any bite victim should still receive prompt medical attention.
Eastern Massasauga Rattlesnake
| Scientific Name: | Sistrurus catenatus |
| Description: | Adult Eastern Massasaugas average 22 to 30 inches (55 to 75cm) long. Their body is light grey with dark brown blotches. |
| Habitat: | Swampy or marshy areas near lakes or streams. |
| Conservation Status: | The Missouri Department of Conservation has listed the Eastern Massasauga Rattlesnake as endangered. It may be extirpated. |
The Eastern Massasauga rattlesnake grows to a length between 22 to 30 inches (55 to 75cm). Their body is a light gray with dark brown blotches. They also have a dark stripe on each side of their face and across their eye. Some melanistic snakes are almost entirely black in color.
Massasaugas have a high-pitched rattle sound, which is different from other rattlesnakes. This is why they have the nickname Buzztail.
Where Do Eastern Massasauga Rattlesnakes Live in Missouri?
Eastern Massasaugas live in eastern Missouri. They live in forested swamplands, marshy grasslands, lake edges, wet prairies, and woodlands.
What Do Eastern Massasauga Rattlesnakes Eat?
Eastern Massasaugas prey on smaller rodents such as mice and voles. They also eat frogs, toads, and small snakes.
How Dangerous Are Eastern Massasauga Rattlesnakes?
The venom of the Massasauga rattlesnake is cytotoxic. Cytotoxic venom destroys body tissue. Moreover, digestive enzymes in cytotoxic venom disrupt blood flow and prevent clotting. Massasauga bites to humans are rare. However, they do occur.
There are two documented deaths in Ontario from Eastern Massasauga envenomations. In each case, the victim did not receive antivenom in time. Source
Western Massasauga Rattlesnake
| Scientific Name: | Sistrurus tergeminus |
| Description: | Adult Western Massasaugas average 14 and 36 inches (36 and 91 cm) long. Their body is light grey with dark brown blotches. |
| Habitat: | Wet habitats such as swamps or marshy areas near lakes or streams. |
| Conservation Status: | The Missouri Department of Conservation has listed the Western Massasauga Rattlesnake as an endangered species. |
Western Massasaugas are the smallest venomous snake in Missouri. Adults grow between 14 and 36 inches (36 and 91 cm) long. Their body is a light gray with dark brown blotches. They also have a dark stripe on each side of their face and across their eye.
Where Do Western Massasaugas Live in Missouri?
The Western Massasauga is listed as an endangered species in Missouri. Snakes are found in the northwestern corner of the state. They are also found in northcentral Missouri. Western massasaugas live in wet prairies with grasses and sedges. They take refuge in crayfish burrows to escape predators and harsh weather.
How Dangerous Are Western Massasauga Rattlesnakes?
The venom of the Massasauga rattlesnake is cytotoxic. Cytotoxic venom destroys body tissue. Moreover, digestive enzymes in cytotoxic venom disrupt blood flow and prevent clotting. Massasauga bites to humans are rare. However, they do occur.
There are two documented deaths in Ontario from Eastern Massasauga envenomation. In each case, the victim did not receive antivenom in time. Source
Wildlife Code of Missouri
All native snakes are protected in the state of Missouri. According to the Wildlife Code of Missouri, lizards, snakes, and turtles are nongame. So, there is no designated hunting season for these animals, and it is unlawful to harm or kill them.
However, there is a practical exception to this rule. When a venomous snake is a direct threat to people, it is permissible to take action. Source
General Symptoms of Venomous Snake Bites
Some of the symptoms you may experience when a venomous snake bites you include:
- Severe pain
- Discoloration in the area of the bite.
- Swelling in the location of the bite.
- Loss of muscle coordination.
- Tingling sensation in the area of the bite.
- Feeling nauseous.
- Having a faster heartbeat or rapid pulse.
What Should You Do if You Are Bitten?
If you or someone you are with has suffered a venomous snakebite, time is of the essence. Because the sooner a victim receives antivenom, the less chance the venom in their body has to cause harm. In other words, it is important to seek immediate medical help.
Do not attempt to kill the snake for identification purposes. This gives the snake a chance to bite you again. Also, consider that severed snakeheads can still bite and envenomate and often do. If you have a phone, take a picture of the offending reptile. Otherwise, get started on your way to the doctor.
First Aid for Snake Bite Victims
- Remain calm and limit your movements. Do not run. If you must hike back to a vehicle, do it calmly and deliberately. Put as little stress on your heart as possible.
- Keep the area of the snake bite below the heart level and never above the heart level. Keeping the bite below the heart level will reduce the venom’s flow. However, holding the bite above your heart level will increase the venom’s flow.
- Remove all constricting items such as bracelets, watches, or rings before swelling occurs.
- Remember that using a cold compress on a venomous snake bite is not advisable. The cold may cause the local blood vessels to constrict and spread the venom faster.
- You can wash the affected area like any other wound with soap and water.
- You may cover the bite area with a moist dressing to reduce the swelling.
- Get medical attention as soon as possible. Call the hospital to tell them a venomous snake has bitten you. So they can have antivenom ready to give you as soon as you arrive.
- A person whom a venomous snake has bitten may go into shock. If this happens, lay them flat and cover them with a blanket.
Dressing for Snake Country
- High-top leather boots and long pants are both wise ideas.
- Also, wear loose-fitting denim. If there’s a gap before the snake’s fangs touch your skin, your chances of being envenomated are lower.
- In the absence of high-top leather boots, some people wear snake gaiters.
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