The Florida subspecies has more prominent facial markings than the Eastern subspecies. Florida Cottonmouth Agkistrodon piscivorus conanti adult, belly Cottonmouths are large, aquatic, venomous snakes. They are heavy bodied with keeled scales. Adult size is considered to be in the range of 30 to 48 inches. The young are more distinctly patterned, resembling a very dark Copperhead Snake , without the reddish tint.
Cottonmouths are common snakes found in wetlands, rivers, lakes, etc.
Their range in South Carolina is usually limited to below the fall line. Many times non-venomous water snakes are mistaken for Cottonmouths. Cottonmouths get their name from their defensive habit of gaping their mouths open to expose the white lining of the mouth. This is their way of warning potential aggressors to stay away. Cottonmouths can be aggressive.