That is a copperhead, very poisonous. He can be confused if around water with the common brown-banded watersnake. The head is the giveaway. That's a viper, for sure. The brown-banded watersnake, sometimes mistakenly called a water mocasin is not poisonous. The cottonmouth IS! The cottonmouth has the same shaped head as this copperhead but will have an indistinct dark grey or almost black design. Most copperheads will retreat if given the chance but a cottonmouth usually will not. They will often move toward you instead of moving away.
Be careful of the copperhead. Most snakebites in Tennessee come without warning from copperheads that have lain quietly until almost stepped on then they bite in a defensive reaction. Best to watch where you walk. OHbytheway, I found through research that the copperhead commonly reaches almost 40 inches in length when fully mature. Your picture is of a fully mature copperhead. Give him a wide berth.
Stay safe, Joe
