Plain-Bellied Water Snake: Habitat, Diet, and Identification Tips

Key Tips

• Plain-bellied water snakes are nonvenomous eastern North American natives.
• Often confused with cottonmouths, plain-bellied water snakes are nonvenomous and harmless.
• Plain-bellied water snakes do not lay eggs — they give birth to fully-formed babies.

What is a Plain-bellied Water Snake 

Plain-bellied water snakes are one species out of the 10 or so in the Nerodia genus. These nonvenomous snakes are harmless to people and eat a variety of fish and amphibians. 

While some sources still recognize up to six subspecies, most experts believe there isn’t enough genetic evidence — leaving only one species of plain-bellied water snake with different regional color morphs. In most cases, the biggest difference between them is the color of their belly.

Where to Find a Plain-bellied Water Snake

INaturalist shows them occupying a huge swath of the southeastern United States. However, they are not as widespread as common water snakes. However, these snakes are common from the east coast of the United States, west to Texas. In the western regions, they occur as far north as Illinois and south into northern Mexico.

This water snake species spends more time away from the water than its cousins but is still never far from a water source. Plain-bellied water snakes live in nearly any freshwater source that is a few feet deep and is slower moving. These snakes enjoy areas with lots of brush and grasses for cover, then slip into water that is often murky.

The only places they don’t live in the southeastern United States are at higher elevations — so you won’t find these snakes in eastern Tennessee and western North Carolina’s mountains.

Diet & Behavior: What Do Plain-bellied Water Snakes Eat 

Like most water snakes, plain-bellied water snakes aggressively defend themselves. Some people see it as being aggressive but this isn’t true aggression. In a fight or flight situation, they choose flight and won’t follow you to keep attacking — an aggressive animal would continue the attack. However, if you corner and try to capture one, you’ll be at the receiving end of their insanely sharp teeth. 

Plain-bellied water snakes hunt anything from fish to aquatic insects and frogs — but because they spend more time out of the water, amphibians like frogs and toads are the most common prey items. These snakes don’t bother with constricting their food, and they aren’t venomous. Instead, plain-bellied water snakes simply grab with their teeth and swallow.

Although they hunt actively, these snakes have also been spotted lying still at the bottom of ponds, waiting to ambush a meal.

Babies and Reproduction

Plain-bellied water snakes do not lay eggs. Instead, they mate during the spring when they emerge from brumation. Then, in mid to late summer, give birth to around a dozen young snakelets.

Although you may have assumed that all reptiles lay eggs, more give birth to their young than you might think. Most vipers — including rattlesnakes, European adders, and even Gaboon vipers give birth. Additionally, garter snakes, water snakes, and boas give birth to their young. 

Experts don’t know what caused these species to hold onto their young instead of laying eggs. However, the benefits it provides are clear and undeniable. Giving birth eliminates the need for a nest to bury or hide eggs for the months of incubation — a period where they are truly helpless. The babies are born ready to meet the world and have a better chance of survival.

How to Identify a Plain-bellied Water Snake 

Young plain-bellied water snakes have brighter patterns with pale outlines that people sometimes confuse with banded water snakes, except these snakes have no markings on their ventral side. Their solid-colored bellies vary and shades of orange, yellow, tan, or reddish-orange are common. As they mature, they become almost solid-colored. In many individuals, all but the pale pattern outlines disappear — leaving pale lines that look like someone marked the snake with chalk.

Plain-bellied water snakes have triangular heads that lead many people to the wrong identification. However, this species is nonvenomous and harmless to people — unless you count their sharp teeth. In these snakes, the eyes have round pupils and are set higher on their heads. If you look from above, their eyes are easily visible. Around their labial, or lip scales, they have dark, vertical lines.

Their necks are noticeably thinner than their head, but not as much as with a pit viper, leading into a stout, muscular body. Plain-bellied water snakes have keeled scales, giving them a somewhat rough appearance. 

Identification Tips

Almost all water snake species get confused with rattlesnakes, copperheads, or cottonmouths at different times. It’s not unusual, especially if you are not comfortable around snakes. But, never fear! Give those snakes a chance to leave and most will slither on out of your way.

Here are a few identification tips that will help you distinguish between a plain-bellied water snake from a cottonmouth.

Eyes, head shape, and facial markings. If someone told you that all venomous snakes have vertical, cat-eye-shaped pupils, they were wrong. Besides, if you’re close enough to see the pupil shape, you are also typically close enough to be bitten. 

While it is true that North American pit vipers like copperheads, cottonmouths, and rattlesnakes have vertical pupils, you may not be able to see the shape in low light. The pupil changes shape — opening and closing to control the amount of light entering it. Not only that, but harmless night snakes have vertical pupils and venomous coral snakes have round pupils. 

So, pupil shape is not a reliable indicator.

What is true is that plain-bellied water snakes have vertical labial bars and venomous North American pit vipers like cottonmouths do not. Instead, many cottonmouths have a dark stripe that starts at their eye and extends backward toward their jaw.

Plain-bellied water snakes have round pupils and eyes set higher on their heads. In contrast, cottonmouths’ eyes are lower and have an enlarged scale over their eyes that makes it nearly impossible to see their eyes when you look down on them.

Although plain-bellied water snakes have triangular heads, they are often softer in appearance. Cottonmouths’ heads have sharply angular features and big cheeks full of venom glands. 

Neck and body thickness. Plain-bellied water snakes have thin-ish necks that connect to stocky bodies. In contrast, cottonmouths and other pit vipers have very thin necks and stout bodies — cottonmouths have very thin tails, but rattlesnakes have well…rattles.  

Behavior. Many pit vipers, including cottonmouths, freeze when they sense danger. They rely on their amazing camouflage to keep out of sight. Some rattlesnakes rattle and back away while hissing. They’re a little obnoxious. Cottonmouths just open their mouths wide and show off their cotton-white mouths. 

Plain-bellied water snakes have a very simple rule: Escape when possible, and bite repeatedly whenever someone grabs them. Remember they eat frogs and fish? Their teeth are specifically designed to hold their slippery prey — razor sharp. These snakes also make use of a stinky weapon — musk. It is an extremely foul-smelling substance they release along with feces from their cloaca. 

Color and Pattern. Young plain-bellied water snakes have dorsal blotches with light-colored stripes between each. Along their sides, thick bars come up from the belly. As they mature, their whole coloration darkens and all that is usually left of the pattern is light chalk lines on their backs and faint bars just above their bellies; they usually turn olive-brown or black as adults.

Young cottonmouths have pixelated bands that sometimes look like chocolate kisses, but not always. There is usually a spot inside their bands, which helps set them apart from their cousins the copperhead. Yet, it’s that bright yellow or green tail that sets them apart from water snakes. As cottonmouths mature, they also become very dark — almost black. Their sharply angular heads and somewhat angry expression also helps tell them apart from water snakes.

The photo featured at the top of this post is © iStock.com/lbolton09