Scientific name: casuarius casuariusCassowaries are very large flightless birds that live in tropical forests of New Guinea and northeastern Australia. The only birds bigger than the cassowary are the ostrich and emu. Cassowaries mainly eat fruit, but will also eat new shoots, seeds and fungi, insects and small animals. Cassowaries usually travel around on their own except when it is time to find a mate and lay eggs. The booming noise the cassowary makes is the lowest known bird call, and is so low humans can only just hear it.