Cottonmouth Snake
Agkistrodon piscivorus
Also called the water moccasin, the cottonmouth is Tennessee's only venomous aquatic snake. Found near ponds, creeks, rivers, and wetlands across Middle Tennessee — including suburban drainage areas and retention ponds.
(615) 613-5992Cottonmouths are venomous. If you've found one near your property, keep people and pets away and call (615) 613-5992 for same-day removal.
Tennessee's venomous water snake.
The cottonmouth is a pit viper closely related to the copperhead, but heavier-bodied, more aggressive when cornered, and strongly associated with aquatic environments. In the Nashville area, they're found along the Cumberland River, its tributaries, and the many ponds, retention basins, and drainage channels that run through suburban neighborhoods.
The name comes from the bright white interior of the mouth, which the snake displays as a warning when threatened — a distinctive defensive behavior that makes identification straightforward if you see it. If you encounter a heavy-bodied dark snake near water that opens its mouth and holds its ground, treat it as a cottonmouth until a professional confirms otherwise.
How to identify a cottonmouth.
Cottonmouths are heavy-bodied and dark — but coloration varies significantly with age and individual. These features are the most reliable identifiers.
White mouth interior
The defining feature: when threatened, cottonmouths gape widely to display the bright white (cotton-white) interior of the mouth. No other Tennessee snake does this reliably.
Heavy, blocky body
Cottonmouths are thick-bodied relative to their length — much heavier than a water snake of the same size. The body tapers abruptly to a relatively thin tail.
Dark coloration
Adults are typically dark brown, olive-brown, or nearly black, often with faint darker banding. Juveniles are more vividly patterned with copper-toned banding similar to copperheads.
Triangular head
The head is broad, flat, and distinctly triangular — noticeably wider than the neck. The facial pit organs between the eye and nostril are visible at moderate range.
Swimming posture
Cottonmouths swim with most of their body on the surface of the water — the body floats high. Non-venomous water snakes swim with only the head above water.
Size
Adults typically 30–48 inches. Large individuals can reach 60 inches. One of the larger venomous snakes in Tennessee.
Cottonmouth lookalikes in Tennessee.
Several common non-venomous water snakes are frequently mistaken for cottonmouths. The northern water snake in particular causes widespread confusion.
Northern Water Snake
Non-venomousThe most commonly misidentified species. Heavy-bodied, dark, found near water, and aggressive when handled — it checks every box that makes people think 'cottonmouth.' Key difference: it swims low in the water, has a more slender head, and lacks the white mouth interior.
Banded Water Snake
Non-venomousFound in the same aquatic habitats as cottonmouths. Has distinct crossbanding that can resemble juvenile cottonmouth patterning. Slimmer body and narrower head than a cottonmouth.
Midland Water Snake
Non-venomousAnother heavy-bodied water snake common in Middle Tennessee. Dark coloration in adults can resemble cottonmouths. Non-venomous but will bite if handled.
Juvenile Rat Snake
Non-venomousYoung rat snakes near water are sometimes mistaken for juvenile cottonmouths due to their blotched patterning. Slimmer body and more pointed head distinguish them.
Where cottonmouths live in Middle Tennessee.
Cottonmouths are semi-aquatic and rarely found far from water. In the Nashville area, that includes a surprising number of suburban locations.
Ponds and retention basins
Suburban retention ponds, HOA ponds, and golf course water features are prime cottonmouth habitat — warm, shallow water with abundant frogs and fish.
Creeks and streams
Any creek or stream in the Nashville area can harbor cottonmouths. They're common along Stones River, Mill Creek, Harpeth River, and their tributaries.
Drainage ditches and channels
Suburban drainage infrastructure — roadside ditches, concrete channels, and culverts — provides shelter and connects water bodies. Cottonmouths use these corridors regularly.
Wetlands and marshy areas
Low-lying areas with standing water, cattails, and emergent vegetation are ideal cottonmouth habitat. Less common in the urban core but present in suburban and rural areas.
Floodplains
The Cumberland River floodplain and the floodplains of its tributaries support significant cottonmouth populations. Flooding events can push them into adjacent neighborhoods.
Basking sites near water
Cottonmouths are frequently seen basking on logs, rocks, and banks at the water's edge. They're less likely to flee than most snakes — they'll hold their ground and display.
Cottonmouth bites: what you need to know.
Serious and potentially life-threatening. Cottonmouth venom is hemotoxic and cytotoxic — it destroys tissue, disrupts blood clotting, and can cause severe local damage. Bites require immediate emergency medical treatment. Fatalities are rare with prompt treatment but tissue loss and long-term complications are possible.
Get away from the snake
Move away immediately. Do not attempt to catch, kill, or photograph the snake. A second strike is a real risk, and the hospital does not need the snake to treat the bite.
Call 911 immediately
Cottonmouth bites are a medical emergency. Call 911 or have someone drive you to the nearest emergency room. Do not drive yourself. Do not wait to see if symptoms develop.
Immobilize and lower the limb
Keep the bitten limb still and below heart level. Remove jewelry and tight clothing near the bite site before swelling begins.
No folk remedies
Do not cut the wound, attempt to suck out venom, apply ice, or use a tourniquet. These methods cause harm and delay real treatment. Antivenom at a medical facility is the only effective treatment.
Frequently asked questions about cottonmouths.
Are cottonmouths aggressive?
More so than copperheads. Cottonmouths are less likely to flee and more likely to hold their ground, gape, and strike if they feel threatened. They won't pursue a person, but they won't necessarily retreat either. Give them wide berth and call a professional for removal.
Is every dark snake near water a cottonmouth?
No — and this is one of the most common misidentifications in Tennessee. Northern water snakes, banded water snakes, and midland water snakes are all dark, heavy-bodied, found near water, and aggressive when handled. The swimming posture (body high on the surface vs. body submerged) and the white mouth display are the most reliable field identifiers. When in doubt, don't approach.
Can cottonmouths bite underwater?
Yes. Cottonmouths can open their mouths and bite while submerged. This is rarely relevant in practice — they don't hunt humans — but it's worth knowing if you're wading in areas where they're present.
What should I do if I find a cottonmouth near my pond?
Keep people and pets away from the area and call a professional for removal. Cottonmouths near residential ponds are a recurring issue in the Nashville area. We can remove the snake safely and assess the property for conditions that attract them.
Are cottonmouths found in Nashville proper?
Yes, though they're more common in suburban and semi-rural areas with natural water features. They're regularly encountered along Stones River, Mill Creek, the Harpeth River corridor, and near retention ponds throughout Davidson, Williamson, Rutherford, and Sumner counties.
Cottonmouth removal near you
We remove cottonmouths from properties near Nashville's waterways and throughout Middle Tennessee.
Cottonmouth near your property? Call us now.
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