American Alligator

Alligator mississippiensis

Description

The American alligator is a large reptile of the southeastern United States. The largest males have grown as long as 16-20 ft (5-6 m), although animals larger than 15 ft (4.5 m) are rare today. Females are usually not longer than about 10 ft (3 m). Alligators have a broad snout and the lower teeth fit into sockets in the upper jaw; unlike crocodiles, whose teeth are positioned outside when the jaws are closed. Adults are colored dark green, gray, or brown, but young animals have bright yellow markings.

Behavior

Juvenile American alligators feed on invertebrates and small fish. Adults mostly eat large fish, but can tackle much larger prey that come within striking range. The adults sometimes excavate microhabitats of deeper water, known as alligator holes, which retain water well into the dry season. They also construct burrows used as shelter during the cooler months of the year.

American alligators breed in the springtime, when the temperature of their aquatic habitat beings to warm up. Various cues are used during courtship, including low-frequency rumbling and bellowing, and vigorous head splashing by the male. The female constructs an elevated nest of rotting vegetation lined with mud and lays 20-50 eggs. The nest is guarded during the incubation period of about 65 days. When the nestlings are ready to hatch, they emit peeping noises, which cues their mother to open up the nest. She carries the hatch-lings to the water in her mouth and may assist some of them in hatching by gently cracking their eggs in her mouth. The juveniles remain close to their mother for as long as three years, receiving a measure of protection from predators by her presence. The females become sexually mature at a length of about 1.8 m (6 ft).

Habitat

The American alligator occurs in a variety of freshwater aquatic habitats, including swamps, marshes, rivers, lakes, and ponds. They sometimes occur in brackish habitats, such as mangrove forest.

Distribution

The historical range of the American alligator included most of the southeastern United States. Its modern range is broadly similar, although extensive areas of habitat have been lost due to in-filling, drainage, pollution and other damages associated with agricultural and industrial development and urbanization.

Threats

The American alligator was also subjected to a relentless commercial hunt for its skin, which was prized for manufacturing a beautiful, fine leather. The over hunting, in combination with habitat loss, resulted in a severe depletion of the populations of the American alligator and the species became endangered throughout its range. Fortunately, beginning in the 1960s, laws were passed to govern the hunting of alligators and the trade in their skins. This has resulted in effective conservation of the species and a substantial increase in their wild populations. In addition, the American alligator is now ranched at more than 150 places in the southeastern United States and these commercial operations have taken most of the exploitation pressure off wild populations of the species. Some wild stocks are now large enough to permit a strictly controlled hunt. The American alligator is no longer listed as a threatened species by the International Union for the Conservation of Nature and Natural Resources (IUCN) and it has been de-listed by the U. S. Fish and Wildlife Service.

Conservation and Recovery

The American alligator is a conservation dependent species because its longer-term security depends on the strict control of its hunting, as well as preventing unacceptable losses of its habitat. Fortunately, these are being done and although threatened, the American alligator is not as endangered as it was several decades ago.

Contacts

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
P.O. Box 1306
Albuquerque, New Mexico 87103-1306
Telephone: (505) 248-6911
Fax: (505) 248-6915
http://southwest.fws.gov/

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

References

Britton, Adam. 2000. "Crocodilian Species—American Alligator (Alligator mississippiensis )." Florida Museum of Natural History. http://www.flmnh.ufl.edu/natsci/herpetology/brittoncrocs/csp_amis.html. [Accessed 3 August 2000].

U.S. Fish and Wildlife Service. "Fact Sheet: American aligator, (Alligator mississippiensis ). U.S. Fish and Wildlife Service. http://species.fws.gov/bio_alli.html [Accessed 3 August 2000].