moa (mōˈə) [key] [Maori], common name for an extinct flightless bird of New Zealand related to the kiwi, the emu, the cassowary, and the ostrich. The various species ranged in size from that of a turkey to the 10-ft (3-m) Dinornis giganteus. The bird had a short stout bill and was wingless—even the shoulder girdle was lacking in most species. Remains preserved in caves and bogs include bones, pieces of skin, feathers, and egg shells. Although the birds were hunted largely by the Maoris, the reason for the moas' extinction is not precisely known. Moas, along with several other orders of extinct and extant birds, belong to a group called ratites, all of which are flightless and share other common anatomical features. It is estimated that there were around 10 species of moas. Moas are classified in the phylum Chordata, subphylum Vertebrata, class Aves, order Dinornithiformes, family Dinornithidae.