Cassowary, (genus Casuarius), any of several species of large flightless birds of the Australo-Papuan region. Cassowaries are the only members of the family Casuariidae and belong to the order Casuariiformes, which also includes the emu. There are three species (counted by some experts as six), each with several races. The common, or southern, cassowary, Casuarius casuarius, which inhabits New Guinea, nearby islands, and Australia, is the largest—almost 1.5 metres (5 feet) tall—and has two long...