Turkeys are large, heavyset galliforms in the genus Meleagris, indigenous to the Americas. They are among the largest birds in their native ranges, as well as being one of the heaviest birds in the order Galliformes. There are two extant turkey species: the wild turkey (Meleagris gallopavo) of Southern, Central and Eastern North America, and the ocellated turkey (Meleagris ocellata) of the Yucatán Peninsula in Mexico. Males of both species have a distinctive singular fleshy wattle, called a snood, that hangs from the base of the culmen. Like with other phasianines, the male is bigger and sports fancier plumage than the female.
The earliest turkeys evolved in North America over 20 million years ago. They share a recent common ancestor with grouse, pheasants, and other fowl. The North American wild turkey is the ancestor of the domestic turkey, which was domesticated approximately 2,000 years ago by indigenous peoples. It was this domestic descendant that was later transported by humans to Eurasia, during the Columbian exchange.