The alligator snapping turtle (Macrochelys temminckii) is one of the heaviest freshwater turtles in the world, having been recently proven outweighed by the Hoan Kiem Turtle, a giant softshell turtle. It is often associated with, but not closely related to, the common snapping turtle, which is in the genus Chelydra. The specific epithet temminckii is in honor of Dutch zoologist Coenraad Jacob Temminck.
Although it was once believed to be only one species, a recent study suggests that it is actually three separate species; Macrochelys temminckii, Macrochelys suwanniensis, and Macrochelys apalachicolae.
The alligator snapping turtle is given its name because of its immensely powerful jaws and long, spring-like neck, as well as distinct ridges on its shell that are similar to the rough, ridged skin of an alligator.