Cassowaries and emus (Cassowariiformes) together form a group of large flightless birds that have long necks and long legs. Their body is covered in shaggy, limp feathers that resemble coarse fur. Their necks and heads are nearly bald. Cassowaries and emus lack a bony keel on their sternum. The keel, when present, provides a crucial anatomical structure necessary for flight—it acts as an anchor to which a bird's flight muscles attach.
Emus are endemic to Australia, where they inhabit grasslands and savannas. Cassowaries inhabit the forests of New Guinea and Australia. Although their ancestors could fly, present-day cassowaries and emus have lost their flight abilities. They have tiny vestigial wings that are far too weak to lift their bulky bodies into the air.
Cassowaries are primarily fruit-eating birds but also supplement their diet with plants and small animals such as insects and small vertebrates. Emus feed on plants and invertebrates. Emus are the largest bird endemic to Australia and the second largest bird in the world (the largest being the ostrich).
