Casuariiformes Casuariiformes The Casuariiformes is an order of large flightless bird that has four surviving members: the three species of cassowary, and the only remaining species of emu. They are divided into either a single family, Casuariidae, or more typically two, with the emu splitting off into its own family, Dromaiidae. All four living members are native to Australia-New Guinea, but some possible extinct taxa occurred in other landmasses. The emus form a distinct family, characterized by legs adapted for running. As with all ratites, there are several contested theories concerning their evolution and relationships. As regards this order, it is
Emu in Australia at the time of European settlement, and one additional species is known from fossil remains. The insular dwarf emus, "D. baudinianus" and "D. n. minor", originally present on Kangaroo Island and King Island respectively, both became extinct shortly after the arrival of Europeans. "D. n. diemenensis", a subspecies known as the Tasmanian emu, became extinct around 1865. However, the mainland sub-species, "D. n. novaehollandiae", remains common. The population of these birds varies from decade to decade, largely being dependent on rainfall; in 2009, it was estimated that there were between 630,000 and 725,000 birds. Emus were introduced to