Photo of gator in water at the Palm Beach Zoo (2013).
An alligator is a crocodilian in the genus Alligator of the family Alligatoridae. The two living species are the American alligator (A. mississippiensis) and the Chinese alligator (A. sinensis). In addition, several extinct species of alligator are known from fossil remains. Alligators first appeared during the Oligocene epoch about 37 million years ago.
The name “alligator” is probably an anglicized form of el lagarto, the Spanish term for “the lizard”, which early Spanish explorers and settlers in Florida called the alligator. Later English spellings of the name included allagarta and alagarto.
A typical adult American alligator’s weight and length is 360 kg (790 lb) and 4.0 m (13.1 ft), but they sometimes grow to 4.4 m (14 ft) long and weigh over 450 kg (990 lb). The largest ever recorded, found in Louisiana, measured 5.84 m (19.2 ft). The Chinese alligator is smaller, rarely exceeding 2.1 m (6.9 ft) in length. In addition, it weighs considerably less, with males rarely over 45 kg.
No average lifespan for an alligator has been measured. In 1937, a one-year-old specimen was brought to the Belgrade Zoo in Serbia from Germany. It is now 76 years old. Although no valid records exist about its date of birth, this alligator, officially named Muja, is considered the oldest alligator living in captivity.
Alligators are native only to the United States and China.
American alligators are found in the southeast United States: all of Florida and Louisiana, the southern parts of Georgia, Alabama, and Mississippi, coastal South and North Carolina, East Texas, the southeast corner of Oklahoma, and the southern tip of Arkansas. According to the 2005 Scholastic Book of World Records, Louisiana has the largest alligator population. The majority of American alligators inhabit Florida and Louisiana, with over a million alligators in each state. Southern Florida is the only place where both alligators and crocodiles live side by side.
American alligators live in freshwater environments, such as ponds, marshes, wetlands, rivers, lakes, and swamps, as well as in brackish environments. When they construct alligator holes in the wetlands, they increase plant diversity and provide habitat for other animals during droughts. They are, therefore, considered an important species for maintaining ecological diversity in wetlands. Further west, in Louisiana, heavy grazing by nutria (coypu) and muskrat are causing severe damage to coastal wetlands. Large alligators feed extensively on nutria, and provide a vital ecological service by reducing nutria numbers.
The Chinese alligator currently is found only in the Yangtze River valley and is extremely endangered, with only a few dozen believed to be left in the wild. Indeed, far more Chinese alligators live in zoos around the world than can be found in the wild. Rockefeller Wildlife Refuge in southern Louisiana has several in captivity in an attempt to preserve the species. Miami MetroZoo in Florida also has a breeding pair of Chinese alligators.