Cassowaries stand between 1.5-2 metres in height and both sexes are similar in appearance. The female is larger and the more aggressive. Cassowaries are the heaviest bird in Australia and tend to be solitary. Mature birds only tolerate each other during the courting and mating process. The male incubates the eggs and sits on them for about 50 days. When the chicks hatch he then takes sole responsibility for rearing them for up to 16 months.