There are A LOT of snakes in South Dakota!
And what’s interesting is that they are all incredibly unique and have adapted to fill many habitats and niches.
You’ll see that the snakes that live in South Dakota are very different from each other.
For example, some species are venomous, while others use constriction to immobilize their prey. Or the fact that certain snakes are rarely seen because they spend most of their time underground, but others are comfortable living EXTREMELY close to humans.
Today, you’re going to learn about the 10 types of snakes in South Dakota!
#1. Prairie Rattlesnake
- Crotalus viridis
- Adults typically range between 3.3 and 5 feet in length.
- Coloration is highly variable and can be greenish-gray, olive green, greenish-brown, light brown, or yellow. All variations have dark blotches on the body that turn into rings near the tail.
- Broad triangular head, elliptical pupils, heat-sensing pits between the eyes and nostrils, and a tail rattle.
These venomous snakes can be found in parts of South Dakota in open prairies, grasslands, and forested environments.
The Prairie Rattlesnake hibernates in South Dakota during the winter, often in communal dens. These dens are typically rock crevices, caves, or old mammal burrows. Individual snakes return to the same den each winter and migrate up to seven miles to their hunting grounds in the spring.
When they feel threatened, these snakes freeze to use their camouflage to avoid detection. They may also quietly crawl away to cover. If approached, they may coil and rattle their tail as a warning before striking. Their potent venom has both hemotoxic and neurotoxic properties, and although rare, can be fatal to an adult human.
Prairie Rattlesnakes are listed on the ICUN Red List as a species of least concern. However, they are considered threatened and declining in parts of their range. In addition, they have faced pressure from habitat fragmentation and hunting.
#2. Northern Watersnake
- Nerodia sipedon sipedon
- Adults range from 24 to 55 inches in length.
- Coloration is pale grey to dark brown with reddish-brown to black bands.
- Large adults become darker with age and appear almost plain black or dark brown.
- Females tend to be larger than males, and coloration is most vivid in juvenile and wet individuals.
This species is the largest snake you will see in the water in South Dakota!
Northern Watersnakes prefer slow-moving or standing water like ponds, lakes, vernal pools, marshes, and slow-moving rivers and streams. They’re most often seen basking on rocks or logs in or near the water.
Northern Watersnake Range Map (Yellow area below)
Credit: Virginia Herpetological Society
These snakes primarily feed on fish and amphibians by hunting along the water’s edge and shallow water during the day. They grab their prey and quickly swallow while it’s still alive!
While non-venomous, they can deliver a painful bite!
Their saliva contains a mild anticoagulant that can cause bites to bleed, making the injury appear worse. These important defense mechanisms help water snakes survive predators such as raccoons, snapping turtles, foxes, opossums, other snakes, and birds of prey.
#3. Red-sided Garter Snake
- Thamnophis proximus parietalis
- Normally dark green to black, but color varies.
- Three yellow stripes; one down the back and one down each side.
- As the name suggests, red or orange bars run along their sides between the yellow stripes.
- Subspecies of the Common Garter Snake.
Like other garter snakes, they are habitat generalists. Look for them in South Dakota everywhere, including forests, shrublands, wetlands, fields, and rocky areas. Their favorite foods include frogs, earthworms, and leeches! YUM! 🙂
In some areas, after emerging from hibernation, there are not enough females for all the males. In these cases, “mating frenzies” occur, and dozens and dozens of these snakes can be found together.
To survive colder months, Red-sided Garter Snakes have to hibernate BELOW the frost line. Depending on the area they are located in, it can be hard to find suitable locations. So the few adequate hibernation dens can shelter hundreds, even thousands, of snakes! To see an example, watch the video below:
#4. Plains Garter Snake
- Thamnophis radix
- Adults average 36 inches in length.
- Coloration is gray-green with a distinctive orange stripe down the back and a greenish-yellow stripe down each side.
- Distinct light yellow spots on the very top of the head!
Plains Garter Snakes are almost always found in South Dakota in prairies and grasslands near freshwater sources. They have a fairly large population and adapt well to human-modified landscapes. You may spot them near abandoned buildings, trash heaps, or vacant lots.
This species is considered one of the most cold-tolerant of all snakes! In fact, they will even come out of hibernation on warmer winter days.
Plains Garter Snakes feed primarily on earthworms, slugs, and small amphibians. However, they have also been observed preying on small mammals and birds, including the Eastern Meadowlark and Bank Swallow.
#5. Western Milksnake
- Lampropeltis gentilis
- Adults typically range from 15 to 34 inches in length.
- Coloration is whitish, black, and reddish or orange bands, with the reddish-orange bands being bordered by black.
- The snout is blackish and sometimes features white flecking, and the underside may have extensions of the bands or be more whitish.
These snakes are found in parts of South Dakota in open sagebrush, grasslands and are occasionally seen in suburban areas. Western Milksnakes are a secretive species frequently found under objects like rocks, logs, boards, and other debris.
Western Milksnake Range Map
Because of their coloration, they are often confused with venomous coral snakes. But luckily, there’s an easy way to tell the difference. Just remember this rhyme:
“If red touches yellow, you’re a dead fellow; if red touches black, you’re all right, Jack.”
These snakes aren’t picky about food and feed on small mammals, birds, bird eggs, other snakes, lizards, reptile eggs, and occasionally, worms and insects. They actively hunt down their prey and use their coils to constrict the life out of them.
Though they’re usually docile when handled, Western Milksnakes do exhibit strong defensive behaviors when disturbed. You can expect them to vibrate their tail (like a rattlesnake), and they may even rear up and strike!
#6. Smooth Greensnake
- Opheodrys vernalis
- Adults are SLENDER and typically range from 14 to 20 inches in length.
- Coloration is uniformly light green with a yellow or white underside and a red tongue with a black tip.
- Juveniles may be olive-green, blue-gray, or even brown until they shed their skin for the first time.
Also called Grass Snakes, these bright green snakes can be found in South Dakota in marshes, meadows, pastures, savannas, open woods, and along stream and lake edges. They prefer moist areas near permanent water sources.
They prey almost exclusively on insects and spiders and don’t use constriction; instead quickly striking and swallowing their prey alive.
Smooth Greensnakes hibernate during the winter in South Dakota, seeking shelter in old mammal burrows and abandoned anthills. They often hibernate communally with other small snakes. They emerge in the spring, typically in April, and are active until October.
Smooth Greensnakes rely on their EXCELLENT camouflage to avoid predators. They’re also agile and can flee quickly if they must.
- Pituophis catenifer sayi
- Adults are large and typically range from 4 to 6 feet in length.
- Coloration is yellow, beige, or light brown with large brown, black, or reddish blotching on the back and three sets of small blotches on the sides.
- Blotches may appear like bands near the end of the tail, and the underside is yellowish with black spots.
Bullsnakes are often seen in South Dakota in areas with high rodent populations.
So they’re common in places like prairie dog towns. But you can also find them in fields, grasslands, forest edges, savannas, and brushlands with sandy soils.
Bullsnakes are fast and can actively pursue prey in loose soil. They even use their prominent rostral (nose scale) to dig! Once they’ve captured their prey, they use their strong body to coil around and constrict their prey.
Despite being nonvenomous, these snakes act aggressively toward any threats. They often lift the front half of their body, hiss, and lunge at their attacker until they feel they can retreat.
Interestingly, their hissing can sound like a rattle! (see below!)
To accomplish this, the snake forces air through an extension of the windpipe, which has a piece of cartilage called an epiglottis that flaps back and forth, sounding very similar to a rattlesnake.
#8. Plains Hog-nosed Snake
- Heterodon nasicus
- Adults range from 15 to 39 inches in length.
- Coloration is varying shades of brown with darker brown blotches on the back, two alternating rows of smaller dark spots down the sides, and large longitudinal blotches on the sides of the neck.
- Enlarged rostral (nose) scale.
The Plains Hog-nosed Snake strongly prefers open sandy or gravelly habitats in South Dakota. They’re excellent burrowers and also use old animal burrows for hibernation and protection from hot temperatures.
These snakes are best-known in South Dakota for their displays when disturbed!
When initially confronted, Plains Hog-nosed Snakes typically remain motionless or hide their head under their coils. They may also try to bury themselves or escape into a burrow.
However, if they’re further disturbed, they’ll spread their jaws and neck like a cobra and puff up their bodies. They may also hiss loudly and deliver false strikes with a closed mouth.
If these intimidating displays fail, the Plains Hog-nosed Snake will then twist as though they’re in pain, roll over on their back and play dead. They’ll be limp, open mouthed, and will remain this way even if picked up. They may also bleed from the mouth and cloaca, expel musk and fecal matter, and regurgitate recently eaten food.
If I saw one of these snakes do this display, I’d definitely leave it alone! But, unfortunately, they’re sometimes killed by people who are frightened by their cobra-like posture.
#9. Dekay’s Brownsnake
- Adults typically range from 6 to 13 inches in length.
- Coloration is light brown or gray to dark brown or black with two rows of dark spots down the back, which are sometimes linked.
- A dark streak down the head and may have a light stripe down the center of the back.
Dekay’s Brownsnakes occupy various terrestrial habitats in South Dakota as long as there’s plenty of cover available such as rocks, logs, boards, and all sorts of trash and organic debris. They’re often found in backyards and gardens under objects.
These secretive, nocturnal snakes hunt during the evening and night, feeding primarily on slugs and earthworms. However, they’ve also been known to consume snails, insects, insect larvae, small tree frogs, tadpoles, frog eggs, spiders, and fish. Prey is typically grabbed and quickly swallowed alive.
These docile snakes usually don’t bite in defense. Instead, if captured, they often squirm vigorously or flatten their bodies and may release foul-smelling musk from glands near the base of their tail.
This species is considered common in most of its range and is not a major conservation concern. It adapts well to human development and has a reputation as a “city snake.” However, pesticide usage and clean-up of cover objects may reduce their populations in urban areas by reducing their habitat and food source.
#10. Western Foxsnake
- Pantherophis ramspotti
- Adults range from 36 to 50 inches in length.
- Coloration is gray, tan, or light brown with large dark brown or reddish-brown blotches down the length of the black and smaller blotches down each side.
- The head is often rust or copper-colored with faded markings, and the underside is off-white or light-yellow with black checkerboard markings.
Western Fox Snakes occupy various habitats in South Dakota.
Look for them in agricultural areas, grasslands, wetlands, and woodlands near water. They’re often found in or around barns and abandoned buildings where rodents and places to hide are abundant. They’re fairly bold snakes and will often travel near humans or other animals.
Foxsnake Range Map
These rat snakes primarily feed on rodents, birds, and bird eggs but will also consume frogs. They’re constrictors and use their coils to suffocate larger prey before consuming it. However, smaller prey may be swallowed whole without constriction.
If disturbed, Western Foxsnakes will often coil and vibrate their tail, producing a noise that sounds like a rattlesnake when it’s in dry leaves. They’re generally non-aggressive but may release a foul-smelling musk and strike if grabbed. Some sources indicate this musk is how these snakes got their name, which was thought to be similar to the scent given off by Red Foxes.
Do you need additional help identifying snakes in South Dakota?
Try this field guide!
Which of these SNAKES have you seen before in South Dakota?
Leave a comment below!
Also, if you enjoy this article, make sure to check out these other South Dakotaguides!