The alligator gar can grow as large as a short-nosed crocodile and possesses a tough armor that helped it survive against predatory dinosaurs.
The North American alligator gar (Atractosteus spatula) lives in rivers, reservoirs, and coastal bays from the southwestern United States to Veracruz, Mexico. It primarily feeds on crabs, fish, birds, mammals, turtles, and carrion, according to Live Science.
The alligator gar is of gigantic size. (Photo: In Fisherman).
With its long snout, thick armored scales, and sharp teeth, this giant fish is often mistaken for a short-nosed crocodile. It is the largest known species within the ancient group of ray-finned fish called gars and can reach lengths of about 2.4 meters.
The alligator gar is “truly a prehistoric monster,” according to biologist Jeremy Wade in the show “River Monsters.” Fossils indicate that they existed 100 million years ago during the Cretaceous period (66 – 145 million years ago), when dinosaurs roamed the Earth.
“Their survival is partly due to a unique defense system made up of scales composed of an ultra-hard enamel called ganoine,” Wade explained. “This armor helps them survive among predatory dinosaurs.” The overlapping hard scales also protect the alligator gar from threats. When alligator gars exceed a meter in length, their only predator is the short-nosed crocodile.
Alligator gars grow very quickly. They hatch from tiny, toxic eggs but can reach lengths of 0.6 meters in their first year. They continue to grow throughout their lives and can live up to 100 years, according to Solomon David, an aquatic ecologist at the University of Minnesota.
The alligator gar is among the few species classified as “living fossils,” which have hardly changed over millions of years. A 2024 study found that the alligator gar has the slowest evolutionary rate among vertebrates with jaws. They evolve so slowly that the alligator gar and the longnose gar (Lepisosteus osseus), two species separated by 100 million years of evolution, can still produce viable hybrids. Such long evolutionary processes typically result in species diverging to the point where they can no longer interbreed.
Although the sharp teeth of the alligator gar can inflict painful bites, they are ambush predators that primarily eat crabs, fish, and birds. In the 1930s, the Texas Parks and Wildlife Commission created an electric fishing tool for alligator gars by shooting 200 volts into the water. Today, alligator gars are protected in Florida and fishing for them is restricted in Texas.
