American Alligator

About the American alligator

The American alligator is a large crocodilian reptile native to the Southeastern United States, one of only two living species in the genus Alligator and the larger of the pair, easily outsizing its closest relative, the Chinese alligator. On average, adult males measure 3.4 to 4.8 m (11.2 to 15.7 ft) and weigh up to 450 kg (1,000 lb). Unverified historical reports describe individuals up to 5.84 m (19.2 ft) and 1,000 kg (2,200 lb), which would make it the heaviest member of the alligator and caiman family, Alligatoridae, and the second-longest living crocodilian after the black caiman. Females run smaller, typically 2.6 to 3.35 m (8.5 to 11.0 ft), and the largest verified free-ranging female measured 3.35 m (11 ft) and weighed 147 kg (324 lb).

Weight varies considerably with length, age, health, season, and food supply, and alligators from the cooler northern edge of the range, such as southern Arkansas, Alabama, and northern North Carolina, tend to stay smaller than those farther south. In mature males, most individuals top out around 3.4 m (11 ft 2 in) and 360 kg (790 lb), while mature females typically reach about 2.6 m (8 ft 6 in) and up to 91 kg (201 lb). Population averages run considerably lower than these maximums: adult males in Newnans Lake, Florida, averaged 2.47 m (8 ft 1 in) and 73.2 kg (161 lb), with females at 2.22 m (7 ft 3 in) and 55.1 kg (121 lb).

Dorsally, adults range from olive to brown, gray, or black, among the darkest coloring of any modern crocodilian, with cream undersides; this dark coloring is one way to tell them apart from crocodiles at a glance. A small number carry a gene that suppresses melanin production and are born albino, a condition so rare that these animals essentially can't survive in the wild, being highly vulnerable to sun and predators. American alligators carry 74 to 80 teeth at a time and replace them roughly once a year, meaning an individual can go through more than 2,000 teeth over its lifetime. The easiest way to distinguish one from the similar-looking American crocodile is the fourth tooth: on an alligator it disappears into a pocket in the upper jaw when the mouth closes, while on a crocodile it stays visible.

Behavior and diet

American alligators are apex predators, eating fish, amphibians, reptiles, birds, mammals, and other American alligators; hatchlings rely mostly on invertebrates before their teeth and jaws mature from small and needle-like into broad and powerful enough for larger prey. They bellow year-round, especially during the breeding season, to declare territory and locate mates, and males use infrasound, sound too low for humans to hear, to draw in females.

Bite force is a defining trait of this species. In laboratory tests, adult American alligators produced the strongest measured bite of any living animal, up to 13,172 newtons, a mark later exceeded by a saltwater crocodile measured in the same lab. Despite that closing force, the muscles that open an alligator's jaw are comparatively weak, weak enough that a captured animal's mouth can be held shut by hand or tape.

On land, alligators move by sprawling or by a straighter "high walk" that lifts the belly off the ground; in water they swim like fish, using side-to-side motion of the tail and pelvis, aided by webbed rear feet. Females build a nest of vegetation, sticks, leaves, and mud in a sheltered spot near water and lay their eggs there. Hatchlings emerge marked with yellow bands and stay under their mother's protection for up to a year, with some parental care extending to three years, unusually long for a reptile. The species is also considered an ecosystem engineer: digging "alligator holes" creates wet and dry microhabitats that other wetland animals rely on.

Range and habitat

American alligators are native to the southeastern United States, found from the South Carolina Lowcountry south to Everglades National Park in Florida and west to South Texas, with populations across North Carolina, South Carolina, Georgia, Florida, Louisiana, Alabama, Mississippi, Arkansas, Oklahoma, and Texas. Louisiana holds the largest state population of any in the U.S. The range has been expanding slowly northward, including into Virginia, where the species had once been extirpated, and a small population has become established in southwestern Tennessee via inland waterways.

Habitat within that range consists of subtropical and tropical freshwater wetlands, particularly marshes and cypress swamps. The American alligator tolerates cooler climates better than its close cousin the American crocodile, but is less tolerant of saltwater, which helps explain why the two species' ranges only partially overlap in the warmest parts of the Southeast.

Conservation status

The American alligator is listed as Least Concern on the IUCN Red List, based on a 2019 assessment. That status follows a major recovery: unsustainable hunting and poaching from the 19th to the mid-20th century, along with habitat loss, drove populations down so far that the species' survival was in doubt.

The alligator was listed as endangered in 1967 under the law that preceded the Endangered Species Act of 1973, and some states acted even earlier; Alabama banned alligator hunting in 1938. Federal protection, state monitoring programs and the work of state wildlife agencies allowed numbers to rebound, and in 1987 the U.S. Fish and Wildlife Service removed the species from the endangered list as fully recovered.

Trade is still regulated. The American alligator is listed on Appendix II of CITES, so international trade in the animals and their parts is controlled, and the Fish and Wildlife Service oversees the legal trade in alligator products. It is the official state reptile of Florida, Louisiana, and Mississippi.