The 6 Types of Water Snakes in Louisiana (with Pictures)

Snakes live throughout the state of Louisiana in just about every kind of environment, but there are several species that prefer to live in or near the water. It’s these snakes that we’re focusing on for this article, the water snakes in Louisiana.

All snakes are capable of swimming in water. While some rarely visit water, others are considered semi-aquatic. For the purposes of this article we are covering the Genus Nerodia, as they are what’s referred to as water snakes. These snakes are in the Family Colubridae and are non-venomous. Water snakes often have large, heavy bodies and are commonly mistaken for venomous snakes. While they can bite if threatened, they are quite harmless if left alone.

With that being said, let’s have a look at Louisiana’s 6 types of water snakes.

6 Types of water snakes in Louisiana

The 6 species of water snakes found in Louisiana are the Diamondback water snake, midland water snake, red-bellied water snake, northern water snake, banded water snake, and the Mississippi green water snake.

1. Midland Water Snake

midland water snake | image by Peter Paplanus via Flickr | CC BY 2.0

Scientific Name: Nerodia sipedon pleuralis
Length: 22-40 inches

The midland water snake is found in southeastern portions of Louisiana. Their main prey items are frogs, fish, and even other snakes. Their coloration is very similar to the copperhead and the cottonmouth, so they’re often mistaken for these two species.

Like all other snakes in the Genus Nerodia, midland water snakes are non-venomous and kill their prey with constriction. They often mimic the behaviors of venomous cottonmouths, though, because their similar color patterns can fool potential predators into thinking they’re more dangerous than they really are.


2. Banded Water Snake

banded water snake | image by Dan Mooney via Flickr | CC BY-ND 2.0

Scientific Name: Nerodia Fasciata
Length: 24-42 inches

The banded water snake inhabits the swamps, rivers and lakes throughout all of Louisiana. They are known to sometimes interbreed with midland water snakes. Although they are harmless and non-venomous, they have a wide, flat head and dark coloration which makes them look very similar to a cottonmouth, a species with which they often share habitat.

Like the midland water snake, the banded water snake favors frogs and fish for prey. Banded water snakes can sometimes behave aggressively, counting on their venomous appearance to deter potential predators. This aggressive behavior is likely the source of the many myths about cottonmouth snakes, which actually tend to be quite reclusive.


3. Diamondback water snake

diamondback water snake | source: USFWS Midwest Region via Flickr

Scientific Name: Nerodia rhombifer
Length: 3-5 feet

The diamondback water snake is predominantly brown, dark brown or dark olive green, with a black pattern along the back, each spot being diamond-shaped. Their scales are a very rough texture and they typically grow to be about 3-4 feet long, though in some cases bigger. The underside is often a yellow or light brown color.

This snake is often confused for a venomous snake, but like all other water snakes diamondback water snakes are not venomous. They are an aggressive snake though and will release musk and fecal matter if provoked.

Like the banded water snake, diamondbacks are also common throughout all of Louisiana. The diamondback water snake enjoys basking on tree limbs above the water and hunting for its prey which includes small amphibians, lizards, mice, etc.


4. Plain-bellied Water Snake

red-bellied water snake | image by Ryan Somma via Flickr | CC BY-SA 2.0

Scientific Name: Nerodia erythrogaster
Length: 24-40 inches

The plain-bellied water snake and its 6 subspecies is named for their bellies that are often red, but can also be a very plain color. The red-bellied water snake (pictured above), is a subspecies of the plain-bellied.

According to a range map on virginiaherpetologicalsociety.com, it appears as though these snakes are found in every county of Louisiana. They live in lakes and swamps but also in rivers. They’re unusual for water snakes in that they will frequently travel long distances over land to a new body of water.

They’re also largely nocturnal, preferring to hunt during the night and spending the whole day basking in the sun. Like other water snakes, they will bite repeatedly to defend themselves, even though they aren’t venomous.


5. Mississippi green Water Snake

green water snake | image by Brandon Trentler via Flickr | CC BY 2.0

Scientific name: Nerodia cyclopion
Length: 2.5 – 3.5 feet

The Mississippi green water snake is common in most of the state of Louisiana. This snake grows to be between 2 and a half feet to 3 and a half feet long and is mostly green or brown with dim black crossbars. Their belly features light spots on grey or brown. Females are typically larger than males and their scales are ridged.

This aquatic snake loves water, but is usually found basking on logs or brush. They are mostly active during the day and feed in the evening on small reptiles, fish, and small animals.


6. Salt marsh snake

saltmarsh snake | image by Scott Beazley via Flickr | CC BY 2.0

Scientific name: Nerodia clarkii
Length: 15-30 inches
Venomous: No

The salt marsh snake has 3 recognized subspecies; the gulf salt marsh snake, the mangrove salt marsh snake, and the Atlantic salt marsh snake. They live in the brackish waters along the coastal regions from Texas to Florida, including Louisiana and even southern Alabama near the Gulf Shores coastline. Here they feed on a variety of small fish and invertebrates.

They are rather small in size in comparison to other water snakes in the Nerodia Genus of snakes. Primarily active at night, these saltwater snakes are not seen in freshwater and obtain the water they need from their prey. Because of their limited habitat along the coasts, these water snakes in Louisiana occur in counties near the coast.

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