There are around 40 snake species found in Oklahoma. Out of these are 7 types of venomous snakes. In this article, we will talk about each of Oklahoma’s venomous snakes. Then, we will tell you where they are found within the state.
- Eastern Copperhead (Agkistrodon contortrix)
- Northern Cottonmouth (Agkistrodon piscivorus)
- Prairie Rattlesnake (Crotalus viridis)
- Western Massasauga (Sistrurus catenatus)
- Western Diamondback Rattlesnake (Crotalus atrox)
- Timber Rattlesnake (Crotalus horridus)
- Western Pygmy Rattlesnake (Sistrurus miliarius)
Pit Vipers
Rattlesnakes, Copperheads, and Cottonmouths belong to the venomous Crotalinae or pit viper family. Pit vipers have heat-sensing pits between their nostrils and eyes. These pits are actually specialized organs that detect body heat from warm-blooded prey. 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.
Pit vipers also have a large triangular-shaped head. It is attached to a comparatively slender neck. Furthermore, they have elliptical pupils that are vertical slits. This is a defining characteristic because non-venomous snakes generally have round pupils.
Pit vipers have hollow fangs connected to venom glands on each side of the roofs of their mouths. They use their fangs to inject venom into their prey. This venom immobilizes the prey, making it easier for the snake to consume. All pit vipers are born with multiple fangs and replace them every couple of months. Old fangs are shed one at a time. Consequently, a pit viper bite may only involve one fang.
Interestingly, these snakes have a sphincter on each venom gland. This allows them to control the flow of venom through the fangs. A pit viper may elect not to inject any venom with a bite. Scientists surmise that this is because it takes time for it to rebuild its venom store. Twenty to twenty-five percent of pit viper-to-human bites are dry bites. In other words, they are venomless. Source
Pit vipers primarily consume small mammals, reptiles, amphibians, small birds, and 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: | Common within their range in Oklahoma. |
The Copperhead population in Oklahoma was formerly divided into two subspecies. These were the Northern Copperhead and Southern Copperhead. 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
The Eastern Copperhead is a pit viper native to the eastern United States.
Copperheads are stout heavy-bodied snakes. Adult copperheads are 20 to 37 inches (50 to 95 cm) long.
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.”
Where Do Eastern Copperheads Live in Oklahoma?
You will find the Eastern copperhead throughout the eastern half of Oklahoma. Look for them in lightly wooded areas. This includes deciduous forests, river bottoms, and rocky wooded hillsides. They utilize leaf litter, tall grass, and other plant debris for cover.
Eastern Copperhead Behavior
Copperheads are dangerous because they use camouflage as their number one defense mechanism. In other words, 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. But, in most cases, they choose to lie perfectly still.
Most copperhead bites on humans occur when the person steps on or near the snake.
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.
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 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 rodents, 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: | Northern Cottonmouth snakes are stout, muscular snakes that grow up to 3 feet (.91m) long. They have a dark body with few markings. Their mouth is white. |
| Habitat: | They favor bodies of water such as swamps, drainage ditches, slow-moving rivers, and lakes. |
| Conservation Status: | Common within their range in Oklahoma. |
Another common name for the Northern Cottonmouth snake is water moccasin. This stout, heavy-bodied snake grows up to 3 feet (.91m) long. They look a little bit like rattlesnakes without the rattle on the tail. People also sometimes mistake them for common water snakes. 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 Oklahoma?
Cottonmouths are semi-aquatic 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. They are located in eastern Oklahoma.
What Do Northern Cottonmouths Eat?
These snakes prey on fish, freshwater crustaceans, amphibians, small mammals, and other reptiles. Cottonmouths sometimes congregate around drying wetland pools to feed on any trapped fish.
How Dangerous Are Northern Cottonmouths?
A Cottonmouth bite contains cytotoxic venom. This means it destroys body tissue. Northern Cottonmouth bites sometimes lead to the amputation of limbs. On rare occasions, death can occur. See
Prairie Rattlesnake
| Scientific Name: | Crotalus viridis |
| Description: | Adult Prairie Rattlesnakes average 3.3 feet (100 cm) in length. They are tan-colored with varying colors of brown blotches covering their bodies. |
| Habitat: | Look for Prairie rattlesnakes in prairies, open grasslands, and forested areas. |
| Conservation Status: | Common within their range in Oklahoma. Federally listed as a species of least concern. |
Adult Prairie rattlesnakes average around 3.3 feet (100 cm) in length. The longest recorded specimen measured just under 5 feet (151.5 cm) long. They are tan-colored with varying colors of brown blotches covering their bodies. They have a distinguishing triangle-shaped head with pit sensory organs on either side. A light stripe runs diagonally from the back of the eye to the jaw. Another strip runs diagonally from below the eye to the corner of the mouth. Prairie rattlesnakes are mostly ground snakes. But they occasionally climb into shrubs, bushes, or trees.
Where Do Prairie Rattlesnakes Live in New Oklahoma?
The Prairie Rattlesnake is found in the Oklahoma panhandle and down the western side of the state.
They live in grassland deserts and pine-oak forests.
How Dangerous Are Prairie Rattlesnakes?
Prairie rattlesnake venom is a mix of hemotoxins and myotoxins. Furthermore, according to some literature, it also has neurotoxins.
Prairie rattlesnake bites can have serious effects. The venom can cause severe pain. It may also induce shock, making the victim feel weak and disoriented. Swelling, blistering, and inflammation can occur at the bite site. Their venom can also damage red blood cells and impair blood clotting. In severe cases, the bite may result in severe tissue damage. There is also a risk of harm to internal organs. Source
Western Massasauga Rattlesnake
| Scientific Name: | Sistrurus tergeminus |
| Description: | 14 and 36 inches (36 and 91 cm) long. Light gray with dark brown blotches. |
| Habitat: | Their preferred habitat is mesic grasslands. |
| Conservation Status: | Vulnerable |
Western Massasaugas are the smallest venomous snakes in Oklahoma. 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 Oklahoma?
These snakes are found in mesic grasslands and prairie hillsides. The Western Massasauga can be found in northern and western Oklahoma.
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
Western Diamondback Rattlesnake
| Scientific Name: | Crotalus atrox |
| Description: | Adults grow from 4 to 7 feet (1.22 to 2.13m) in length. They have diamond-shaped blotches along their back. |
| Habitat: | Their habitats include rocky canyons, plains, deserts, desert grasslands, and forests. |
| Conservation Status: | Common within their range in Oklahoma. |
Western Diamondback rattlesnakes grow from 4 to 7 feet (1.22 to 2.13m) in length. Their base color varies. It can be yellow, light brown, salmon, gray, gray-brown, cream, or olive. They have dark diamond-shaped patterns along their backs. This is why they have the name “Diamondback.” The edges of their dorsal spots are darker than the centers. The centers are a bit darker than their base color. Their tails have two to eight black bands separated by pale gray bands. A dark line runs from the corner of the mouth to behind the eye.
This species has various names, including the Western Diamond-backed Rattlesnake and Adobe Snake.
Where Do Western Diamondback Rattlesnakes Live in Oklahoma?
Western Diamondback Rattlesnakes are found all throughout Oklahoma. Their habitats include rocky canyons, plains, deserts, desert grasslands, and forests.
How Dangerous are Western Diamondback Rattlesnakes?
Western Diamondback Rattlesnake venom is Hemotoxic, cytotoxic, and myotoxic. If a Western Diamondback bite goes untreated, it can cause serious problems. These include severe internal bleeding and tissue damage, which might result in gangrene. Source
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 black chevron-shaped crossbands. 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: | Common within their range in Oklahoma. |
The Timber Rattlesnake is sometimes called Eastern timber rattlesnake or Canebrake Rattlesnake. Generally, in higher-elevation habitats, they are called Timber Rattlesnakes. On the coastal plain, though, they’re called Canebrake Rattlesnakes.
The average Timber Rattlesnake grows between 36 and 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. This chevron pattern turns to dark bands on their dark brown or black tails. They also 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 black phase of these snakes, the tail is also darker than the rest of the snake’s body.
Where Do Timber Rattlesnakes Live in Oklahoma?
The Timber Rattlesnake lives in various habitats. These include deciduous forests, pine forests, swamps, farm fields, and river floodplains. These snakes are excellent climbers and have been found in trees at heights of more than 80 feet.
They are found in wooded areas in central to southeastern Oklahoma.
Wintertime Brumation
As we discussed in the section on copperheads, snakes brumate in the winter. Brumation is a reptile’s version of hibernation.
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. These wintertime dens may hold up to 60 snakes.
How Dangerous Are Timber Rattlesnakes?
Timber Rattlesnakes are among the most dangerous snakes in North America. This is due to their large size, long fangs, and high venom yield. 1% to 10% of the time, an untreated Timber Rattlesnake bite results in a fatality.
The good news is that these snakes have a relatively mild disposition. They generally give ample warning before actually striking defensively. Also, 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. In other words, it destroys red blood cells. Timber Rattlesnake bites sometimes cause serious complications. These include shock, seizures, coma, internal bleeding, and deep tissue damage. Source
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: | Least Concern |
The Western Pygmy Rattlesnake is a small, slender-tailed snake with a tiny rattle. Adults average length is 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 Oklahoma?
This species lives throughout much of south-eastern Oklahoma. 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.
Symptoms of Venomous Snake Bites
Some of the symptoms you may experience when a venomous snake bites you include:
- Discoloration in the area of the bite.
- Swelling in the area 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 treatment.
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 nearest hospital.
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 when 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.
