Thank you for your question. Excellent photograph! This is one of the watersnakes in the genus Nerodia. Based on your location this could be a cross between two subspecies: the northern watersnake, N. sipedon sipedon and the midland watersnake, N. sipedon pleuralis, or it could be a midland watersnake, N. sipedon pleuralis. The border between the distribution of the midland watersnake and the area where they interbreed with the northern watersnake is very close to Hamilton County. All members of the genus Nerodia are non-venomous.
The northern watersnake and its subspecies have a wide distribution extending from portions of Maine south to the panhandle of Florida and as far west as portions of Colorado. They can be found in just about any type of aquatic habitat, including rivers, lakes, ponds, creeks, swamps, bayous, marshes and wetlands. They are also commonly found in water features in home owners' backyards. They often bask on rocks and fallen trees in or near the water. They also climb into bushes and small trees with branches that overhang the water, where they bask in the sun.
These are thick-bodied snakes. Typical adult length is slightly under 3 feet, and maximum length can reach approximately 5.5 feet.
The northern watersnake has one of the most varied diets of any of our North American species. Research has shown that their diet includes over 80 species of fish and 30 species of amphibians.
If threatened, these snakes always attempt to escape into the water. If you corner them, they will spread their jaws and flatten the front portion of their body to make themselves appear larger and will strike and bite repeatedly if you get too close. If you pick one up, they will twist their body in an attempt to escape, while biting you and expelling a strong-smelling musk from their anal glands.
Because this species' range often coincides with that of the venomous cottonmouth (Agkistrodon piscivorus), and because they have thick bodies similar to the body shape of the cottonmouth, they are often misidentified as cottonmouths, and needlessly killed.
Here's a link to the Tennessee Wildlife Resources Agency's website page for this species:
If you would like to learn more about this and other snake species in your area, here is an excellent field guide:
Gibbons, Whit. (2017). Snakes Of The Eastern United States. Athens: University of Georgia Press.
I hope this answers your question, and thank you for contacting Ask an Expert.
Thank you so much for your timely and detailed answer. Altho I have a healthy fear of snakes I find them fascinating and I want to be able to identify them so thank you again.
You're welcome. Contact us any time.