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
Flightless bird 85–92 days while females feed. They can go up to a week without eating and survive only off fat stores. The emu has been documented fasting as long as 56 days. If no continued pressures warrant the energy expenditure to maintain the structures of flight, selection will tend towards these other traits. Many flightless birds are extinct; this list shows species that are either still extant, or became extinct in the Holocene (no more than 11,000 years ago). Extinct species are indicated with a dagger (†). A number of species that are suspected, but not confirmed to be flightless, are