Average adult length: 26 in (66 cm); average adult weight: 175 lbs. (80 kg); appearance & coloration: large, heavy head, and a long, thick shell with three dorsal ridges of large scales (scutes) with three distinct rows of spikes and raised plates on the carapace (shell); solid gray, brown, black, or olive-green in color, and often covered with algae. The tail is almost as long as the shell itself and, together with the chin, throat and neck, is coated with long, pointed tubercles (small wart-like or angular swellings). They have radiating yellow patterns around the eyes, which are also surrounded by a star-shaped arrangement of fleshy filamentous “eyelashes.” Male and female can be differentiated by the position of the cloaca from the carapace and the thickness of the tail’s base. A mature male’s cloaca extends beyond the carapace edge; a female’s is placed exactly on the edge if not nearer to the plastron. The base of the tail of the male is also thicker as compared to females because of the hidden reproductive organs.