The alligator gar, Atractosteus spatula, is a primitive ray-fin fish. It is also referred to as the gator gar. Unlike other gars, the mature alligator gar possesses a dual row of large teeth in the upper jaw. It is these remarkably alligator-like teeth which gives it its name. The dorsal surface of the alligator gar is a brown or olive-color, while the ventral surface tends to be a lighter color. Their scales are diamond-shaped and interlocking (ganoid) and were once used by native Americans for jewelry.
The alligator gar is the largest species of gar and is the largest exclusively freshwater fish in North America and Asia. It can be as long as eight to twelve feet and often weighs at least 100 lbs at maturity. The current world record alligator gar weighed 279 pounds and was caught in the Rio Grande River in 1951. Even larger alligator gars — over 300 pounds — have been caught by trotliners.