EMU or. EMEU, the name given to Ratite birds of the family Dromaeidae. With the cassowaries (q.v.), the emus form the order Casuariiformes, peculiar to the Australian region and char acterized by the fact that the "after-shaft" of each feather is as long as the main shaft (see TAE ; FEATHER) . The emus differ from the cassowaries in having feathers on the head, no helmet or cervical caruncles, and in bearing on their inner toes a peculiar claw. The best known species is Dromaeus novae-hollandiae of S.E. Australia. Next to the trich the largest of living birds, the emu has been much diminished in numbers by constant tion. It inhabits open country, feeding on fruits, roots and age and keeping in small panies. The nest is a shallow pit in the ground containing 9 to 13 blue-green eggs, which are incubated by the cock. The young at birth are clad in striped down. The peculiar structure of the trachea is correlated with the loud booming note of the bird during the breeding season. This, or an allied species, formerly inhabited Tasmania.