6 Most Snake-Filled Bodies Of Water In The United States

Give a snake warm shallows, thick shoreline cover, and plenty of fish and frogs, and it will stay close. That is why a handful of American waters hold serpents at a density open water never could. Some of these snakes earn their keep. The Lake Erie watersnake now eats mostly round goby, an invasive fish that wrecked the lake's native prey. Florida's story runs the other way, where released Burmese pythons have spread through the Everglades and gutted the local mammals. The six waters below hold the country's thickest and strangest snake communities. They include an earthquake-born lake in Tennessee, a python-altered slough in Florida, and the largest river swamp in the United States.

Reelfoot Lake, Tennessee

A series of violent earthquakes along the New Madrid seismic zone in the winter of 1811 and 1812 dropped this corner of northwest Tennessee and let the Mississippi flood in, drowning a cypress forest and leaving the shallow lake that stands today. Reelfoot is one of several U.S. lakes that sit on fault lines, and it is really several habitats stitched together, with bayous, marshes, and freshwater sloughs feeding into the main water, and around 30 snake species live across those varied habitats. Most are water snakes and semi-aquatic species such as the Mississippi green watersnake and the broad-banded watersnake, whose bands run from brown through red-brown to red.

The Mississippi green watersnake is often mistaken for the cottonmouth, which matters because the cottonmouth is venomous and the watersnake is not. The most reliable difference is the eye: the green watersnake has a round pupil, while the pit viper's is vertical. In the muddier shallows, the red-bellied mudsnake shelters under waterlogged timber and hunts aquatic salamanders, its glossy black body broken by a red-checkered belly. Cottonmouths are present but not a common sight, using shoreline cover while hunting; a threatened one gapes to show the white mouth lining that gives the species its name.

Mobile-Tensaw River Delta, Alabama

Alabama holds about 49 native snake species, one of the richest totals in the country, and a large share of them live in and around its waterways. The Mobile-Tensaw River Delta is the state's largest wetland, roughly 260,000 acres of swamp and marsh running about 45 miles inland from Mobile Bay. Because it blends open water, marsh, brackish estuary, and bottomland forest, it holds both venomous and non-venomous species side by side. Cottonmouths are common across Alabama and especially abundant here, since they tolerate the brackish water better than most snakes.

Walk the delta edge at low tide and you may find a Gulf saltmarsh snake working the stranded fish left along the shore. Several protected animals share the wetland, including the federally endangered Alabama red-bellied turtle. The southern hognose snake was once part of this fauna too, but it has not been reliably confirmed in the state for decades and may be gone from Alabama entirely.

Shark River Slough, Florida

The largest snake here is the one that never belonged. The Burmese python, released intentionally or by accident through the exotic pet trade, has established itself across the Everglades, and Shark River Slough carries the slow sheet flow at the heart of that range. The pythons are rarely seen even where they are numerous, which is exactly what makes them so hard to control. Their spread has driven steep declines in raccoons, opossums, and other mid-sized mammals, rewiring the food web, and no native predator meaningfully hunts a full-grown adult.

The Florida Fish and Wildlife Conservation Commission pays contracted hunters through its python removal program to find and kill the constrictors, slow work given how well the snakes disappear against leaf litter and tree bark. Native venomous species live here too, including the dusky pygmy rattlesnake and the cottonmouth. Both are venomous but neither seeks out people, and most bites happen only when a snake is stepped on or cornered.

Caddo Lake, Texas and Louisiana

Caddo is a flooded cypress forest straddling the Texas-Louisiana line, its channels threaded with Spanish moss and stranger plants like American lotus and cabomba. One of the busiest stretches for paddlers and reptiles alike is the Turtle Shell Paddling Trail, a 4.6-mile loop out of Uncertain, Texas. More than 15 snake species live in and around the water. The western ribbon snake shows a pair of bright yellow stripes as it basks under cover, while the scarlet snake wears red banded with black; it looks venomous but is harmless beyond the sting of a bite.

Non-venomous water snakes dominate, among them the plain-bellied water snake and the diamondback water snake, which skim the surface or hunt frogs along the edge. The one venomous species to watch for is the copperhead, most often seen along the banks in spring. Snakes do well here because their prey does: frogs and mice are thick on the shore, the water is full of fish, and the shade of the old cypress and lily pads keeps the reptiles from overheating.

Atchafalaya Basin, Louisiana

This distributary of the Mississippi is the largest river swamp in the United States, a flooded forest running roughly 150 miles down south-central Louisiana. Serpents do well in the warm, slow water, and several species work the channels and overhanging branches. The speckled kingsnake, marked with pale yellow flecks on black, hunts other snakes near the surface, while the banded water snake alternates between draping itself over low limbs and swimming the shallows.

Two venomous species stand out. The copperhead often holds still rather than fleeing when startled, relying on the hourglass banding that breaks up its outline against floating leaves. The cottonmouth, a heavy-bodied viper with a broad triangular head, tends to freeze or retreat when it meets a person. The non-venomous Mississippi green watersnake is less forgiving, and a cornered one can deliver a hard, painful bite.

Western Lake Erie Islands, Ohio

The rocky shorelines of the western Lake Erie islands hold a snake found almost nowhere else. The Lake Erie watersnake, a subspecies of the common watersnake, is a nearly uniform gray, its ancestral banding faded to almost nothing, which lets it vanish against the limestone. It once fed on native fish and amphibians, but when the invasive round goby overran the lake in the 1990s and crushed those native populations, the snake switched prey. The goby now makes up about 90 percent of its diet.

The new prey did more than feed the snake. By eating gobies in large numbers, the watersnake helps check an aggressive invader, and the abundant food drove such a strong recovery that the subspecies was removed from the federal threatened list in 2011. It stands as a rare case of a native predator turning an ecological problem into an advantage.

Reading the Water

Across these six waters the same pattern holds: dense cover, warm shallows, and heavy prey populations concentrate snakes far beyond what open water would. The specifics differ, an earthquake lake in Tennessee, a brackish delta in Alabama, a python-altered slough in Florida, but the ecological role is consistent. Snakes keep rodent and fish numbers in check, and in the case of the Lake Erie watersnake they blunt an invasion outright. They rarely have any interest in people and conceal themselves under logs and foliage; most bites come from a snake that was cornered or grabbed. Given room to leave, nearly all of them simply will.