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Cassowaries: Casuaridae

Behavior And Reproduction

Cassowaries are solitary birds except during mating and the egg-laying period. They are normally shy but when threatened, can attack, kicking and slashing victims with their sharp claws. Although they do not fly, they are good swimmers and fast runners.

A male cassowary is territorial, meaning it is protective of an area it considers home and claims exclusively for itself and its mate. A male's territory is approximately 2.8 square miles (7 square kilometers) in size. Females have overlapping ranges belonging to several males.

During the breeding season that starts in May or June, the female lays three to eight large, dark, bright green or greenish blue eggs in a nest that is incubated by the male. The female then moves on to lay eggs in several other males' nests. Incubation lasts from forty seven to sixty one days. The male cares for the chicks for nine months after they hatch.

After about nine months, the young cassowaries leave the nest and the males go off in search of an area they can claim as their own territory. The average lifespan of cassowaries in the wild is believed to be forty to fifty years.

The big birds play a critical role in the health of the rainforest of northern Australia and New Guinea by dispersing the seeds of more than 150 types of trees through their excretions. It is the only way seeds of at least eighty trees get dispersed.

Two species of cassowaries, the dwarf cassowary and the southern cassowary, found in the rainforests of Papua New Guinea, make a very low booming sound, deeper than that of most birds, that can barely be heard by humans.


Cassowaries are considered the most dangerous bird in the world. Though normally shy, when cornered or threatened, the cassowary will lash out, charging their victim, kicking and slashing with their razor-sharp claws. In 1999 there were 144 documented cassowary attacks on humans in Australia, six causing serious injury. There were also cassowary attacks on dogs, horses, and one cow. The last reported death from a cassowary attack occurred in 1926 when a sixteen-year-old boy was killed by a single kick to the neck after hitting the bird with a stick.

Scientists believe the sounds are meant to call for a mate or to claim a territory. "Such low frequencies are probably ideal for communication among widely dispersed, solitary cassowaries in dense rainforest," wrote Andrew L. Mack, a scientist with the Wildlife Conservation Society, in the October 2003 issue of the scientific journal The Auk. "The discovery of very low-frequency communication by cassowaries creates new possibilities for studying those extremely secretive birds and for learning more about the evolution of avian vocalizations."

Additional topics

Animal Life ResourceBirdsCassowaries: Casuaridae - Physical Characteristics, Behavior And Reproduction, Southern Cassowary (casuarius Casuarius): Species Account - GEOGRAPHIC RANGE, HABITAT, DIET, CASSOWARIES AND PEOPLE, CONSERVATION STATUS