The alligator gar (Atractosteus spatula) is an ancient freshwater fish known for its substantial size and resemblance to the American alligator. This “living fossil” has a torpedo-shaped body, a broad snout, and sharp teeth. Its lineage dates back over 100 million years. Its body is covered in ganoid scales, which are nearly impenetrable and offer robust protection. Native to North America, its range extends from the Mississippi River basin south to the Gulf of Mexico and coastal areas spanning from Florida to Veracruz, Mexico. The alligator gar also possesses the unique ability to breathe both air and water.
Alligator Gar Size Explained
Alligator gar commonly measure 6 to 6.5 feet (1.8 to 2 meters) in length and weigh over 100 pounds (45 kg). While 79 inches is a common length, these fish can grow significantly larger, with maximum reported lengths up to 10 feet (3 meters) and weights up to 350 pounds (159 kg). Their lifespan typically ranges from 20 to 50 years, with the oldest recorded specimen estimated at 94 to 95 years old.
Alligator gar exhibit rapid growth in their early years, often exceeding 5 inches in their first month and reaching 30 inches by their first winter. This growth slows considerably as they mature. A 6-foot alligator gar is typically 10 to 30 years old and weighs around 100 pounds. Achieving a length of 7 feet may take 40 years. Female alligator gar generally grow larger and live longer than males.
What Influences Alligator Gar Growth
Several factors contribute to an alligator gar’s growth, including environmental conditions and biological characteristics. Optimal habitat quality plays a significant role, with the largest specimens often found in extensive, healthy river systems, oxbow lakes, swamps, bayous, and large reservoirs. These fish prefer large rivers with access to overflow floodplains, which provide spawning and nursery areas. Habitat degradation, such as that caused by dams and levees, can negatively impact their populations.
Abundant food availability is another important environmental factor. Alligator gar are ambush predators that primarily consume other fish, but their diet can also include blue crabs, waterfowl, small mammals, and turtles. A consistent diet rich in protein supports robust growth. Water temperature also influences growth, with warmer temperatures generally promoting higher metabolic rates and faster development. Ideal water temperatures for spawning and early development range from 68 to 86°F (20 to 30°C); extreme temperatures can hinder egg hatching and larval development.
Biological factors, such as age and genetics, also dictate growth potential. While young gar experience rapid growth, this rate slows significantly with age as energy is redirected towards reproduction and maintenance. Individual genetic variations contribute to differences in maximum size. Female alligator gar typically grow faster, reach larger sizes, and have longer lifespans than males. Females usually attain sexual maturity around 11 years, while males mature earlier, around 6 years.
Documented Largest Alligator Gar
The largest alligator gar ever officially recorded, though not an International Game Fish Association (IGFA) record due to how it was caught, weighed 327 pounds (148 kg) and measured 8 feet 5.25 inches (2.57 meters) long with a 47-inch girth. This fish was unintentionally caught in a net by commercial fisherman Kenny Williams in Mississippi’s Lake Chotard in 2011. Estimated to be between 50 and 95 years old, the specimen was donated to the Mississippi Museum of Natural Science for display.
The current IGFA All-Tackle World Record for alligator gar is 279 pounds, a fish caught by Bill Valverde in the Rio Grande, Texas, on December 2, 1951. This gar measured 93 inches (2.36 meters) long. In September 2023, angler Art Weston caught a 283-pound alligator gar in the Sam Rayburn Reservoir, Texas. This fish, measuring 8 feet 4 inches long with a 48-inch girth, is a pending IGFA all-tackle world record and a 6-pound line class record. After being weighed and measured, this specimen was released back into the reservoir. Historically, anecdotal accounts mention alligator gar reaching up to 350 pounds and 10 feet in length, with one unverified report citing a 350-pound gar from the St. Francis River, Arkansas, in the 1930s.