Florida is home to 45 species of native snakes, six of which are venomous (poisonous). The venomous species include five pit vipers (Eastern Diamond-backed Rattlesnake, Timber Rattlesnake, Pygmy Rattlesnake, Copperhead, and Cottonmouth) and the Coral Snake. Copperheads and Timber Rattlesnakes have a limited range in Florida. Copperheads only occur in a small area of Florida's Panhandle just west of Tallahassee, and Timber Rattlesnakes are only found in northern Florida as far south as Gainesville and in limited portions of the Panhandle. The other four venomous species are found throughout the state. Florida's venomous snakes occur in a variety of natural habitats, ranging from swamps to dry woods.
The five species of pit vipers all share several characteristics. The pupils of their eyes are vertical (cat-like) and they have a deep facial pit between each eye and nostril.
These characteristics can be difficult to see unless a snake is examined closely, so do not rely on them to differentiate venomous from non-venomous species. 
Florida's pit vipers have blocky, triangular-shaped heads that are distinctly broader than their necks. Relative to their length, these species are heavy-bodied snakes.