All of Tennessee's venomous snakes are from the Pit Viper family.They get that name from having a heat sensing pit just behind each nostril, which they use in sensing their prey.
The 4 Venomous Snakes of Tennessee are:
The venomous snakes of Tennessee have elliptical (cat eyed) shaped pupils. If a snake in Tennessee has round pupils, it is nonvenomous, also most have thick bodies and blunt tails. They have triangular shaped heads but some larger nonvenomous snakes appear to have the same head shape. They have a single row of scales on their bellies above their anus, whereas all of our nonvenomous snakes have two rows of belly scales. If you find a snakeskin that has a single row of belly scales, then it is from a venomous snake.
Of all the venomous snakes in Tennessee, the Cottonmouth has the meanest temperament. They will stand their ground when encountered, and they will give you a good dose of venom with each bite. Contrary to old wives tales, the Cottonmouth can bite underwater. All snakes in Tennessee have white mouths; so do not base your identification of a Cottonmouth on that criterion alone.
The Timber and Western Pigmy Rattlesnakes are easier to identify because both have a button at the end of their tails that they rattle in self-defense, to warn predators away (they add a button each year as they shed their skin). The buttons are extremely fragile, so determining the age of the snake cannot be determined from the amount of buttons present. If the Rattlesnake is startled and must defend itself in an instant, then it will not rattle its tail.
The Copperhead is a relatively shy snake, but they account for the most reported bites each year in Tennessee. They will inject venom based on the amount required to render its prey inactive. They know that they cannot digest a human, so roughly 50% of their bites are dry bites; meaning that when they bite, no venom is injected.
*Notable mention; the Scarlet King Snake in Tennessee resembles the venomous Coral snake of the Southern United States. A way to distinguish between the two is an old rhyme that my mother taught me when I was young. "Red and black, friendly Jack, … red and yellow, kill a fellow." Meaning that if the red color band of the snake touched the black band; then it is a harmless Scarlet King snake, but if the yellow band of the snake touches the black band; then it is a venomous Coral snake.