The alligator gar, Atractosteus spatula, is a primitive ray-finned fish. They are related to bowfin in the superorder Holestei (ho’-las-te-i). Unlike other gars, the mature alligator gar has a dual row of large teeth in the upper jaw. Its common name was derived from its striking resemblance to the American alligator, particularly its elongated head and sharp teeth. The dorsal surface of the alligator gar is a brown or olive color, while the ventral surface tends to be lighter. Alligator gars don’t have scales like other fish, rather their bodies are armored with overlapping ganoid scales that are diamond-shaped, and composed of a hard enamel-like bony substance that is nearly impenetrable.
Along with its status as the largest species of gar, the alligator gar is one of the largest freshwater fish found in North America, measuring approximately 8 to 10 ft (2.4 to 3.0 m), and weighing an average of 200 lb (91 kg) at maturity.