American Alligator: Species Profile
The American alligator (Alligator mississippiensis) ranges throughout the southeastern United States, and alligators within Everglades National Park exist at the southern extreme of their range. Alligators primarily inhabit freshwater swamps and marshes and can also be found in rivers, lakes, and smaller bodies of water. They can tolerate a reasonable degree of salinity for short periods of time and are occasionally found in brackish water around mangrove swamps even though they lack the salt-secreting glands present in crocodiles. Dens are burrowed out and used for shelter and aestivation when winter temperatures fall or more commonly in the Everglades, when conditions are very dry. Even outside their dens they can tolerate limited periods of freezing conditions. During the winter dry season they modify their habitat by excavating “alligator holes,” which also provide a refuge for other animals during dry periods.
Adult male alligators occasionally reach 13 to 15 feet in length. Maximum length for females is approximately 10 feet. Both sexes tend to be smaller in South Florida. The snout of an alligator is characteristically broad, although the shape can vary slightly among populations and individuals. The bright yellow cross-bands that juvenile alligators sport against a black background provide effective camouflage. The yellow banding fades away as the juveniles mature. Juveniles eat a wide variety of small invertebrates, particularly insects, as well as small fish and frogs. The adult diet typically consists of fish, turtles, small mammals, birds, and reptiles, including small alligators. Feeding activity is governed by water temperature, and foraging ceases if the temperature drops below 68 to 73 degrees Fahrenheit. The color of adult alligators varies with habitat and can be olive, brown, gray, or nearly black, with a creamy underside. Algae-laden waters produce greener skin, while tannic acid from overhanging trees can produce darker skin.