An alligator is a crocodilian in the genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Alligator of the family Alligatoridae

Alligatoridae

Alligatoridae is a family of crocodylians that includes alligators and caimans.- True alligators :Alligators proper occur in the fluvial deposits of the age of the Upper Chalk in Europe, where they did not die out until the Pliocene age. The true alligators are now restricted to two species, A...

. There are two extant alligator species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

: the American alligator

American Alligator

The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...

 (Alligator mississippiensis) and the Chinese alligator

Chinese Alligator

The Chinese alligator or Alligator Alligator sinensis) is one of two known living species of Alligator, a genus in the family Alligatoridae. The Chinese alligator is native only to China...

 (Alligator sinensis).

The name alligator is an anglicized form of , the Spanish term for "lizard", which early Spanish explorers and settlers in Florida

Florida

Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

 called the alligator.

Alligators have a variety of successful adaptations to their ecological niche that have allowed these reptiles to remain almost unchanged since the Cretaceous.
The alligator is notorious for its bone-crushing bites.