Knoxville lies at the heart of eastern Tennessee, a largely urbanized area that nonetheless also includes Great Smoky Mountains National Park. This portion of the state, which borders North Carolina, Kentucky and Georgia, hosts significant biological diversity, including 23 of the 32 native Tennessee snake species.

Most of the 23 snake species in eastern Tennessee don’t have venom. This diverse non-venomous roster includes the eastern milk snake, ring-neck snake, smooth earth snake, eastern worm snake, red-bellied snake, Dekay's brown snake, scarlet snake, rat snake, corn snake, black racer, rough green snake, queen snake, eastern ribbon snake, common garter snake, northern pine snake, southeastern crowned snake, eastern hog-nosed snake and the northern water snake.

Of the four venomous snakes in Tennessee, the timber rattlesnake and the copperhead inhabit the state’s eastern portion. Both are pit vipers, using heat-sensing pits just behind their nostrils to detect prey. Timber rattlers can grow to over 6 feet long, and, as their name implies, prefer forested terrain. Copperheads are smaller – usually 3 feet long or less, occasionally approaching 4 1/2 feet – and also generally frequent timbered habitat, from dry hillsides to wetland margins.

The northern water snake is a resident of eastern Tennessee that dwells in and near water, eating frogs, fish and mammals. People sometimes mistake this common, nonvenomous species for an equally common venomous snake, the cottonmouth. Also called water moccasins, cottonmouths are pit vipers and inject prey with hemotoxic venom, which breaks down red blood cells. Although they bear a superficial resemblance to northern water snakes in pattern and coloration, cottonmouths are restricted to western Tennessee: You won’t find them in the eastern part of the state.

Snakes play a vital role in controlling pest populations. None of Tennessee's 32 snakes are federally listed as endangered or threatened, though the state list classifies the western pigmy rattlesnake as threatened and the Mississippi green water snake as "in need of management." However, it's illegal in Tennessee to "harm, kill, remove from the wild, or possess" any native snake, unless you have the appropriate permits. Releasing captive snakes into the wild can introduce disease and parasites.