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Alligator

Alligator mississippiensis

Appearance

The American alligator is a large aquatic reptile and is one of two crocodilians native to Florida. Alligators can be distinguished from the American crocodile by head shape and color. Alligators have a broad, rounded snout with no lower teeth visible when their jaw is closed. The American crocodile has a narrow snout, and the fourth tooth of the lower jaw protrudes when closed. Adult alligators are primarily dark gray in color with a lighter color underside, although juvenile alligators will have light colored stripes on their sides for camouflage. American crocodiles are a brownish gray color, and are generally paler colored than alligators. It is not uncommon for alligators to take on the colors of their environment. Many people associate alligators with the color green, but this misconception comes from the green algae and floating vegetation that frequently adheres to an alligator’s back.

Female alligators rarely exceed 10 feet in length, but males can grow much larger. The Florida state record for length is a 14-foot 3 1/2-inch male from Lake Washington in Brevard County. The Florida record for weight is a 1,043 pound (13 feet 10-1/2 inches long) male from Orange Lake in Alachua County. Armored plates (scutes) cover the body dorsally, and alligators have a vertically flattened tail.

Habitat

Native Range of the American Alligator

Courtesy of US Geological Survey, Nonindigenous Aquatic Species Program.

Alligators occur from southeast Oklahoma and east Texas on the western side of their range to North Carolina and Florida in the east. They prefer fresh water lakes and slow-moving rivers and their associated wetlands, but they also can be found in brackish water habitats and rarely in salt water.

Behavior

Alligators are opportunistic feeders. Their diets include prey species that are abundant and easily accessible. Juvenile alligators eat primarily insects, amphibians, small fish, and other invertebrates. Adult alligators eat rough fish, snakes, turtles, small mammals, and birds.

Nearly all alligators become sexually mature by the time they reach about 7 feet in length although females can reach maturity at 6 feet. A female may require 10 to 15 years and a male 8 to 12 years to reach these lengths. Courtship begins in early April, and mating occurs in May or June. Females build a mound nest of soil, vegetation, or debris and deposit approximately 32 to 46 eggs in late June or early July. Incubation requires approximately 60-65 days, and hatching occurs in late August or early September.

From an average clutch size of 35, an estimated 4 alligators will reach maturity. This estimate is for a growing alligator population. As an alligator population matures (and has a higher percentage of large animals), the survival rate would be expected to be lower, in part due to a higher rate of cannibalism.

Alligators are ectothermic (cold blooded). They regulate their body temperature by basking in the sun or moving to areas with warmer or cooler air or water temperatures. They are most active when temperatures are between 82° to 92° F. They stop feeding when the ambient temperature drops below approximately 70° F, and they become dormant below 55° F. Alligators are dormant throughout much of the winter. During this time, they can be found in burrows that they construct adjacent to an alligator hole or open water, but they occasionally emerge to bask in the sun during periods of warm weather.

Threats

The main threat facing the American alligator is the destruction and degradation of wetland habitat.  Destruction of wetlands frequently occurs in association with human development. Alligator nests may be depredated by raccoons and bears, and juveniles are vulnerable to predation by wading birds, otters and larger alligators.

Conservation and Management

The American alligator is Federally protected by the Endangered Species Act as a Threatened species, due to their similarity of appearance to the American crocodile, and as a Federally-designated Threatened species by Florida’s Endangered and Threatened Species Rule.

Information on the management of alligators in Florida can be found on the Alligator Management Program web pages.