6-12'. They have a stout, elongated with a broad, rounded snout; the head is wide and flattened with eyes slightly raised on head. When the jaws are closed, only the downward-pointing teeth of upper jaw is visible. Legs short, heavy claws, and tail square in cross section, vertically compressed toward tip; 6 raised ridges on back merge into 2 atop tail. Black to slate gray; throat and chest yellowish white. Young black with bold yellowish-white bands.
Ponds, swamps, rivers, freshwater, and brackish marshes mangroves, canals; ocean (rare)
During droughts, deepens a pool in marsh that benefits other aquatic life. Hibernates in muddy wallows in cooler months in northern Florida. Caution; usually docile; dangerous if surprised or closely approached, especially near nests. Adult male bellowing roar. Adult female; softer roar; pig-like grunts. Young; high pitched yunk.