The American alligator (Alligator mississippiensis), sometimes referred to colloquially as a gator or common alligator, is a large crocodilian reptile endemic to the southeastern United States. Alligators are usually found in freshwater, slow-moving rivers. They also live in swamps, marshes and lakes. They can only tolerate salt water for brief periods because they do not have salt glands.

This monstrous reptile has very strong and wide opening jaws. Inside those mighty jaws adorn 74 to 80 sharp, pointy teeth. Their jaw can crack a turtle shell. Alligators are basically carnivores, but they eat more than just meat, feeding on anything from sticks to fishing lures to aluminum cans. They eat fish, snails and other invertebrates, birds, frogs and mammals that come to the water's edge. They use their sharp teeth to seize and hold prey. They swallow small prey whole. If the prey is large, they shake it apart into smaller, manageable pieces. If it is very large, they will bite it, then spin on the long axis of their bodies to tear off easily swallowed pieces.

Besides swimming, American alligators walk, run, and crawl. When alligators wish to increase speed they diagonally opposite limbs move forward almost simultaneously. This allows for faster movement, but it also decreases the animal's stability. They are agile swimmers. They tend to float on water, completely submerged with only nostrils and eyes above water to look out for prey. It digs a deep hole in mud when the weather is extreme hot or cold. This den is called gator hole. Unlike other reptiles, American alligators do not hibernate during winter. It becomes dormant though.

Once on the verge of extinction, the American alligator has made a remarkable recovery due to strict conservation measures and extensive research. It is no longer endangered except in scattered areas of its range. However, the federal government lists it as threatened because it is very similar in appearance to the American crocodile. Because the American crocodile is endangered, the government does not want hunters to confuse the two different types of animals. Hunting is allowed in some states but it is strictly controlled.