Macrochelys is a genus of large freshwater turtles in the family Chelydridae, best known for the alligator snapping turtle (Macrochelys temminckii). Native to the southeastern United States, these turtles inhabit slow-moving rivers, swamps, and marshes. They are distinguished by their rugged, heavily ridged shells, powerful jaws, and a unique worm-like appendage on their tongues used to lure prey. Macrochelys species are among the largest freshwater turtles in North America, with impressive longevity and slow growth rates.