Venomous vs. Non-Venomous Snakes in Charleston SC: How to Tell and What to Do

South Carolina has 38 snake species. Six of them are venomous. So when you find a snake coiled under your crawl space door on James Island or stretched across the warm pavers in West Ashley, the odds are already in your favor. Most snakes you'll see in the Lowcountry can't hurt you. But the six that can are all here, and a few of them are common.

The problem is that people kill the wrong snakes constantly. They mistake a harmless water snake for a cottonmouth, or a young rat snake for a copperhead, and they go after it with a shovel. That's when bites happen. Nearly every snakebite we hear about in the Charleston area came from someone trying to handle or kill the animal, not from someone who walked away.

Here's how to tell what you're looking at, and what to actually do about it.

The six venomous snakes in the Charleston area

All six of South Carolina's venomous species can turn up in the Lowcountry, though some are far more common than others near the coast. Five are pit vipers. One is not.

Copperhead (Agkistrodon contortrix). This is the one you're most likely to encounter in a yard. Copperheads are tan to copper colored with distinct hourglass or Hershey's Kiss shaped crossbands that are wide on the sides and narrow across the spine. They hold still and rely on camouflage, which is exactly why people step near them in leaf litter and pine straw. Common across Mount Pleasant, Summerville, and wooded subdivisions throughout the county. Their bite is painful and needs medical care but is rarely fatal.

Cottonmouth (Agkistrodon piscivorus), also called the water moccasin. Dark, thick bodied, and tied to water. You'll find them near ponds, ditches, marsh edges, and the tidal creeks that run through Johns Island and the sea islands. Adults often look nearly solid brown or black. When threatened they gape, showing the white cotton colored lining of the mouth, which is where the name comes from. This is the snake people most often misidentify, because several harmless water snakes share the same habitat.

Eastern diamondback rattlesnake (Crotalus adamanteus). The largest venomous snake in North America. Heavy bodied with a chain of dark diamonds outlined in lighter scales. More common in the pine flatwoods and undeveloped sea island habitat than in neighborhoods, but Johns Island and the rural edges of the county still have them. You usually hear the rattle before anything else.

Timber rattlesnake (Crotalus horridus), called the canebrake rattlesnake in the coastal plain. Pinkish gray to tan with dark crossbands and often a rusty stripe down the back. Found in wooded and swampy areas inland from the coast, more common toward Summerville and the upper county.

Pigmy rattlesnake (Sistrurus miliarius). Small, often under two feet, gray with dark blotches and sometimes a reddish dorsal stripe. The rattle is so tiny it sounds like an insect buzz. Easy to overlook.

Eastern coral snake (Micrurus fulvius). The only one that isn't a pit viper. It's an elapid, related to cobras, and its venom works differently. Brightly ringed in red, yellow, and black with a black nose. Rare near the coast and secretive, but present in sandy pine habitat. More on telling it apart below.

How to tell a venomous pit viper from a harmless snake

Five of the six are pit vipers, and they share a set of features you can read from a safe distance. You do not need to get close. You do not need to catch it. You just need to look.

Head shape. Pit vipers have a broad, triangular head that's distinctly wider than the neck, because the venom glands sit behind the eyes. Non-venomous snakes have narrower, more rounded heads that blend into the body. This is the fastest tell, but it isn't perfect, because some harmless snakes flatten their heads to bluff when scared.

Pupils. Pit vipers have vertical, elliptical pupils like a cat's eye. Non-venomous snakes have round pupils. True, but only useful if you're close enough to see the eye clearly, which you shouldn't be.

The heat pit. Pit vipers have a heat sensing pit between the eye and the nostril, giving them what looks like an extra nostril on each side. Again, a close range feature.

Tail scales. On the underside of the tail past the vent, pit vipers have a single row of scales. Non-venomous snakes have a double row. This is a dead snake feature, not something to check on a live one.

Here's the honest version. In the field, you're mostly going by head shape, body thickness, pattern, and behavior. Pit vipers tend to be stocky and hold their ground. Most harmless snakes are slender and flee fast. If a snake races away from you the second you appear, it's almost certainly not a pit viper.

The coral snake rhyme actually matters here

The coral snake breaks all the pit viper rules. Narrow head, round pupils, no pit, slim body. You tell it by the color order. On a coral snake, the red and yellow bands touch each other. The old rhyme holds in the Southeast: red touches yellow, kills a fellow; red touches black, friend of Jack. The harmless scarlet kingsnake and scarlet snake have red bands bordered by black. A coral snake's red is bordered by yellow, and its snout is solid black. Use the rhyme only in the Carolinas and the rest of the US. It does not hold in other parts of the world.

The harmless snakes people kill by mistake

These are the ones that get flattened with a garden hoe because someone panicked. Learn them, because they're your neighbors and several of them eat the animals you actually don't want around.

Black racer (Coluber constrictor). Solid satin black, slender, fast, with a white chin. Probably the snake you'll see most often crossing a yard in broad daylight. Harmless and jumpy. It'll be gone before you finish reaching for anything.

Eastern rat snake (Pantherophis alleghaniensis). Large, can top five feet, variable in color from gray to yellowish with faint blotches. Excellent climbers, which is why you'll find them in sheds, on fence lines, and occasionally in attics hunting rodents. Juveniles are strongly blotched and get mistaken for copperheads constantly. A young rat snake has round pupils, a narrow head, and gray and brown blotches rather than copperhead's clean hourglass bands.

Corn snake (Pantherophis guttatus). Orange to reddish with bold red blotches ringed in black. Beautiful and completely harmless. People see red and assume danger. They're some of the best rodent control the Lowcountry has.

Banded and brown water snakes (Nerodia species). These take the worst of it. They share every pond, ditch, and creek bank with the cottonmouth and they look superficially similar. The differences: water snakes have rounder heads, round pupils, and they bolt into the water or drop off a branch when disturbed. A cottonmouth tends to stand its ground, swim with its head held high and most of its body riding on top of the water, and gape when cornered. When in doubt, back away from any snake near water and don't assume.

Kingsnakes (Lampropeltis species). Including the scarlet kingsnake. These eat other snakes, including venomous ones, and they're immune to pit viper venom. Killing a kingsnake in your yard is genuinely counterproductive.

Why snakes show up on your property

Snakes don't want to be near you. They show up because something is drawing them, and almost always that something is food or shelter.

The food is rodents. If you have rats or mice around the house, you have the main reason snakes come close. Rat snakes, kingsnakes, racers, and copperheads all hunt rodents, and a property with an active rodent problem is a buffet. This is why snake sightings and attic rodent activity often go together. If you're hearing scratching overhead too, that's worth reading about separately, because the fix for the rodents removes the draw for the snakes. We cover that in our guides on rat removal.

The shelter is clutter and gaps. Woodpiles, leaf litter, tall grass, stacked brick, debris against the foundation, and open crawl spaces all give snakes cool, dark, humid places to hide. Charleston's raised houses and vented crawl spaces are made of exactly this kind of habitat. A crawl space with a broken door or a missing vent screen is an open invitation, the same way it is for other ground level wildlife. The same conditions that bring one animal bring others. We see this constantly with the critters that den low and dig, like the ones in our writeup on why armadillos are wrecking Charleston yards, whose abandoned burrows become ready made snake shelter.

Water is the third draw, and in the Lowcountry it's everywhere. Retention ponds, drainage ditches, marsh edges, and tidal creeks all support frogs, fish, and the snakes that eat them.

What to do if you find a snake

Stop and give it room. Six feet is plenty for most situations. A snake can only strike roughly a third to half of its body length, and it would far rather leave than fight.

Do not try to kill it. This is almost always the wrong call, and it's how people get bitten. A dead or injured snake can still deliver a reflexive bite for a surprising amount of time after it appears dead. You also risk killing a harmless species, or a venomous one you misidentified, while standing within strike range.

Do not try to catch or move it yourself. No matter what you saw on a video. Handling snakes is how professionals get bitten too.

If it's outside and moving away, let it go. A snake crossing your yard is passing through. It isn't staking a claim.

If it's inside the house, keep everyone and pets out of that room, close interior doors to contain it, and if there's an exterior door nearby, open it so the snake has an exit. Then call for help.

If it's venomous, or you can't tell, or it's in a spot you can't avoid like a doorway, crawl space, or garage you need to use, call a professional. Our team handles snake removal in Charleston and will identify the species, remove it safely, and tell you what was drawing it in the first place.

If someone is bitten

Get to an emergency room. Keep the bitten limb below heart level, stay as calm and still as possible, and remove rings or tight clothing before swelling starts. Do not cut the wound, do not try to suck out venom, do not apply a tourniquet, and do not ice it. Those old methods make outcomes worse. If you can safely note the snake's color and pattern from a distance, that helps the hospital, but never go back to catch or photograph it up close.

Prevention that actually works in the Lowcountry

You reduce snakes by removing what they come for.

Deal with rodents first. A property without a food supply is far less interesting to a snake. Keep woodpiles off the ground and away from the house. Clear leaf litter, cut back tall grass and dense ground cover near the foundation, and keep shrubs trimmed up off the dirt. Store firewood and building materials away from the structure.

Close the gaps. Seal the foundation, screen the crawl space vents, and replace a crawl space door that doesn't seal. Opossums, which happen to prey on snakes and are highly resistant to pit viper venom, slip through the same openings, and so does nearly everything else. If you've got animals getting under the house already, that's the same vulnerability a snake will use. Our post on what Charleston homeowners deal with when an opossum gets in the crawl space walks through how those entry points get found and sealed. Proper crawl space work shuts the door on all of them at once.

Snake repellent granules sold at the hardware store do essentially nothing. Save your money for habitat work and exclusion, which actually change whether a snake wants to be there.

Call (843) 212-1147 to schedule an inspection.

Wildlife Removal Services

Humane removal and permanent exclusion for raccoons, bats, squirrels, snakes, and more in Charleston, SC.