Parrots or Psittacines; order Psittaciformes) includes about 353 species of bird which are generally grouped into two families: the Cacatuidae (also called cockatoos), and the Psittacidae (also called true parrots). All members of the order have a characteristic curved beak shape with the upper mandible having slight mobility in the joint with the skull and a generally erect stance. All parrots are zygodactyl, having the four toes on each foot placed two at the front and two back. Parrots can be found in most of the warm parts of the world, including India, southeast Asia and west Africa, with one species – now extinct – in the United States (the Carolina Parakeet). By far the greatest number of parrot species, however, come from Australasia, South America and Central America.