American Alligator

American Alligator

American Alligator

Alligator mississippiensis

Status: Threatened

Classification: Reptile


American alligators are large crocodilians found only in the United States. They can grow to be more than 12 feet (3.6 meters) in length and weigh as much as 1,000 pounds (450 kilograms), with males being slightly larger than females on average. The animal’s dark skin is armored with small, bony scales called scutes.

A long, powerful tail helps propel the animal through water, as do webbed feet. They are cold-blooded and depend on the natural world around them to provide warmth. To do this, they will bask in the sun or dig holes in mud to trap heat. Although American alligators can be hard to miss while basking on the shore, they can look eerily like logs when floating in the water.

A cousin of the alligator, the American crocodile, is very rare in the U.S. and only a few thousand individuals live on the southern tip of Florida. The best way to tell the difference between an alligator and a crocodile is by looking at the mouth. Alligators have a wide, round snout, while crocodiles have a long, thin snout. Crocodiles also have two large teeth that stick out when their mouth is closed.


American alligators can be found in the coastal wetlands of the U.S. Southeast, as far north as North Carolina and as far west as eastern Texas. Their range extends down to southern Florida and includes the Everglades. These reptiles are usually found in slow-moving freshwater rivers, but also inhabit swamps, marshes, and lakes.


American alligators are carnivores. They eat fish, invertebrates, frogs, birds, and mammals. They use their sharp teeth to capture prey, and their strong jaws are powerful enough to crack a turtle’s shell.

American alligators hunt predominantly at night. If large prey is captured, they drag it underwater, where it is drowned and devoured. Additionally, American alligators have an adaptation in throat called a glottis. This allows them to capture prey completely submerged in water.


Alligators have a variety of means of locomotion. They can swim, walk, run, and even crawl. Unlike most reptiles, alligators walk with their legs directly beneath them, as opposed to diagonal. This allows them to lift their tails off of the ground while they move.

As a cold-blooded reptile, alligators undergo dormancy when the weather becomes cold. They are known to dig tunnels 65 feet (20 meters) long to protect themselves from extreme heat and cold.

Life History

American alligators usually start reproducing at 10 to 12 years old. They breed in shallow water, and after mating, the female begins building a nest out of nearby vegetation. A female can lay up to 90 eggs in her nest, which she then covers with more vegetation. To let their mother know they’re ready to hatch, the young alligators make a high-pitched noise from inside their eggs. Eggs hatch are incubating for roughly 65 days. Many young alligators are eaten by predators such as birds, snakes, fish, and mammals, but are usually safe after they reach four feet (1.2 meters) long. These alligators can live to be 50 years old.


American alligators were once threatened by extinction, but after being placed on the endangered species list in 1967, their population increased. This species is now classified as least concern. The main threat to these reptiles today is habitat loss caused by wetland drainage and development.

The American alligator is an important keystone species of the Southeast. Alligators use their tails to dig burrows in mud for nesting and to keep warm. When an alligator abandons a burrow, the hole left behind fills with freshwater and is utilized by other species for breeding and drinking. If alligators are removed from their native ecosystem, it would affect countless other species.

Fun Fact

As an American alligator’s teeth wear down or fall out, new ones come in. An alligator can go through 3,000 teeth in a lifetime.


Animal Diversity Web, University of Michigan Museum of Zoology

National Geographic

National Park Service

Smithsonian’s National Zoo and Conservation Biology Institute

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