Venomous Snakes of South Dakota

Prairie Rattlesnake

The Prairie Rattlesnake is the only venomous snake species in the U.S. state of South Dakota.

This article will cover South Dakota’s Prairie Rattlesnakes in particular.

We’ll also spend some time on pit vipers and rattlesnakes in general. In as much as Prairie Rattlesnakes fit into both of these categories.

We’ll also list some species of snakes in South Dakota that get mistaken for rattlesnakes.

Pit Vipers

Pit Vipers in the United States are Rattlesnakes, Copperheads, and Cottonmouths. They all belong to the venomous Crotalinae or pit viper family. Pit vipers have a facial pit between their nostril and eyes on each side of their face. 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. See

These snakes also have a triangular head attached to a slender neck. Furthermore, the pupils of their eyes are vertical slits.

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 amount of venom going through the fangs. A snake may elect not to inject any venom with a bite. Scientists surmise that this is because it takes time 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 viper food sources include small mammals, reptiles, amphibians, small birds, and insects. These snakes play an important role in maintaining balance in rodent populations.

Rattlesnake graph


The first thing people think about with regard to rattlesnakes is their tails. When they are disturbed, they vibrate their rattles using their tail muscles. This makes a buzzing or rattling-type sound. The specific purpose of the rattle is to warn larger animals to stay away. Sometimes, rattlers strike without rattling, though. Sometimes, their rattles fall off. Here’s something else to consider. Some Black Hills rattlesnakes have a genetic defect snake experts call curly-q tail. It prevents them from rattling. Source

You must be aware of where you place your hands and feet in rattlesnake country. If you hear a rattling noise, do not move until you spot where it’s coming from. Otherwise, you may accidentally move into the snake, provoking it to strike you. You should carefully move to a safe distance when you’ve located the snake. But carefully scan your surroundings because the snake you see might not be the only one around.

When moving through known rattlesnake habitat, you should have your dog on a leash. If you have hunting dogs, they should be wearing snake armor.

It’s a good idea to carry a long stick. You can use it to tap the ground in front of you to warn any snakes of your approach. You can also use the stick to part any dense vegetation or tall grass in your path.

If you are hiking in rattlesnake country, it would be a good idea to wear snake boots or snake gaiters. This protects your lower legs from being bitten by a snake.

Prairie Rattlesnake
Prairie Rattlesnake

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 open prairies, grasslands, and forested areas.
Conservation Status:Common within their range in South Dakota.

The Prairie Rattlesnakes’ average length is 3ft to 5ft (.91 to 1.5 M) long. Their background coloration is tan colored. Over this, they have varying shades 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 its eye to its jaw. Another strip runs diagonally from below its eye to the corner of its mouth.

Prairie Rattlesnakes are ambush predators. This means they will sit and wait until their prey comes by before striking. They use their pit organs and tongues to sense their prey.

All snakes, including prairie rattlesnakes, flick their tongues to smell the air. They are able to pick up tiny chemical particles that help them zero in on their prey. See

Map of the Prairie Rattlesnake Range in South Dakota
Prairie Rattlesnake Range in South Dakota

Where Do Prairie Rattlesnakes Live in South Dakota?

Prairie Rattlesnakes inhabit an extensive area. Their range takes in the entirety of the Great Plains from Mexico to Southern Canada. Their territory also extends to parts of the western United States.

Prairie Rattlesnakes are distributed throughout western South Dakota. To be precise, they live in every county west of the Missouri River. They are also present to a more limited extent in eastern South Dakota. They have been observed in Edmunds, Walworth, Potter, Beadle, Sully, Hughes, Hyde, Lincoln, Charles Mix, and Bonne Homme counties.

Prairie rattlesnakes inhabit a variety of habitats throughout their range. True to their name, they favor prairies and open grasslands. But they also inhabit wooded areas such as the spruce forests of the Black Hills. They are more likely to be located in or near rocky outcrops or prairie dog towns. Prairie dog town snakes eat the original owners and then shelter in prairie dog burrows.

Prairie Rattlesnakes are mostly ground snakes. But they occasionally climb into shrubs, bushes, or trees.

These snakes also enter the urban areas of South Dakota. Terry Phillip is the snake curator at Reptile Gardens. He says, “There isn’t a corner, a street, or a neighborhood in Rapid City where he hasn’t had to capture a rattlesnake. They’re everywhere.” See

Rattlesnake combat dance
Rattlesnake combat dance Dawn Endico CC-by-sa-2.0

Prairie Rattlesnake Behavior

South Dakota prairie rattlesnake activity is the highest from April to October. They spend the coldest winter days in underground dens.

Bumation is a reptile’s version of hibernation. Prairie Rattlesnakes brumate in communal dens. But their hunting grounds extend as far as seven miles from their dens in the summertime. In the warmer months, prairie rattlers might shelter in old mammal burrows. But in the fall, they will return to their communal dens.

These snakes mate in the late spring and early summer. Male Prairie Rattlesnakes participate in combat rituals. They do this for the right to mate with receptive females. When they do this, they face each other with their heads and part of their bodies elevated off the ground. They then intertwine and attempt to knock each other to the ground. The snake that doesn’t get knocked to the ground wins breeding privileges.

Pregnant female Prairie Rattlesnakes give birth to 8 to 17 babies in late summer. Like the majority of pit vipers, rattlesnakes are viviparous. This means that they give live birth rather than laying eggs.

Baby Prairie Rattlesnakes are born fully equipped to take care of themselves. They are on their own after a few days.

What Do Prairie Rattlers Eat?

A Prairie rattlesnake’s favorite food is small mammals. Accordingly, mice, rats, rabbits, ground squirrels, and prairie dogs are on their menu. They will also eat ground-nesting birds, lizards, and other snakes.

How Dangerous Are Prairie Rattlesnakes?

Prairie rattler venom is a mix of hemotoxins and mycotoxins. 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 hemotoxic venom can also damage red blood cells and impair blood clotting. On the other hand, myotoxic venom contains digestive enzymes that destroy body tissue. In severe cases, the bite may result in severe tissue damage. There is also a risk of harm to internal organs. Source

Brian Smith is a biologist and associate professor at Black Hills State University. He specializes in the study of snakes and snake venom. He says that Prairie Rattlesnakes in the Black Hills have venom that is unique. It has two or three enzymes not found in Prairie rattlesnake venom outside the Black Hills. These extra enzymes might give the Black Hills snakes a more potent bite. Source

A Red-Tailed Hawk Feeds on a Large Snake

Rattlesnake Predators

Rattlesnake Predators That Are Immune to Rattlesnake Venom

Although they are venomous, Prairie Rattlesnakes do have some potential predators.

  • One of these is the North American Racer. These snakes are immune to snake venom. They pin down their prey with their body and swallow it alive. Consequently, they are probably limited to very small rattlesnakes. North American Racers have been recorded eating rattlesnakes in the Black Hills. Source
  • The non-venomous Western Milksnake’s coloration imitates that of venomous coral snakes. Western Milksnakes kill by constriction. They are immune to snake venom. Consequently, they sometimes prey on South Dakota’s Prairie Rattlesnakes.
  • Skunks also prey on rattlesnakes. Fortunately for them, they are also immune to snake venom.
  • Badgers also eat rattlesnakes and have some immunity to rattlesnake venom. In some states like South Dakota, badgers are the top predators of rattlesnakes.
  • Feral hogs are also immune to snake venom and find rattle snakes to be tasty snacks.

Rattlesnake Predators That Are Not Immune to Rattlesnake Venom

The following animals occasionally prey on rattlesnakes but are not immune to their venom. They have to manage to kill the snake without being bitten.

  • coyotes
  • bobcats
  • mountain lions
  • raptors

Rattlesnake Lookalikes in South Dakota

Bull Snakes

The Bull Snake is the largest snake in South Dakota. People often mistake bull snakes, which are also called gopher snakes, for rattlesnakes. This is primarily because they are similarly marked. Bull snakes are nonvenomous snakes. But they can do a pretty fair rattlesnake impression when they’re agitated. They do this by coiling in a defensive posture and flattening their heads. They even vibrate their tails sometimes. The best way to differentiate between a bull snake and a rattlesnake is to observe the tail. Bull snakes don’t have a rattlesnake’s rattle. Instead, their tail comes to a fine point.

Western Hognose Snakes

South Dakota is also home to the Western Hognose snake. The western hognose snake is a rear-fanged colubrid snake and is mildly venomous. However, they are not dangerous to humans.

Western hognose snakes are also called plains hog-nosed snakes or blow snakes. They are relatively short and stout-bodied. Their color pattern is variable. But most subspecies of this snake resemble a rattlesnake in coloration.

When threatened, these snakes flatten their heads, hiss, and vibrate tails like rattlesnakes. They also may bluff strike without opening their mouths. This is more like a head but than a strike. As a last resort, they play dead.

Western Fox Snakes

Western Fox Snakes are an endemic species to southeastern South Dakota. They are similarly marked to rattlesnakes. Also, like our first two examples, they do the tail shake when they’re agitated. These snakes sometimes face persecution when people mistake them for rattlesnakes.

Baby Rattlesnakes

Ryan Comer is a reptile keeper at Reptile Gardens in Rapid City. He says baby rattlesnakes resemble baby bullsnakes or Yellow-Bellied Racers. That’s dangerous because baby rattlesnakes come fully equipped with fangs and venom. The best way to identify a baby rattlesnake is to look at the tail. They won’t have rattles yet. However, they will have a blunt-ended tail with a single button. Source

Symptoms of Venomous Snake Bites

Some common symptoms you may experience from a venomous snake bite 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 an abnormally rapid pulse.

What Should You Do If A Venomous Snake Bites You?

If you or someone you are with has suffered a venomous snakebite, time is of the essence. The best way to ensure a positive outcome is to treat the victim with anti-venom as soon as possible. In other words, it is important to seek immediate medical attention.

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. If you have a phone, the best thing to do is take a picture of the offending reptile. Otherwise, get started on your way to the 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 treatment as soon as possible. Call the hospital to tell them a venomous snake has bitten you. So they can have anti-venom 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.

Also see: Scorpions in South Dakota – Krebs Creek

Are There Elk in South Dakota ? – Krebs Creek

Wild Cats in South Dakota – Krebs Creek

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