Southern Cassowary

About the southern cassowary

The southern cassowary, also called the double-wattled cassowary, Australian cassowary, or two-wattled cassowary, is a large, flightless, mostly black bird found in Indonesia, Papua New Guinea, and northeastern Australia. It's one of three living cassowary species, alongside the dwarf cassowary and the northern cassowary, and as a ratite it's related to the emu, ostrich, rhea, and kiwi — with cassowaries and emus forming sister lineages within the family Casuariidae. Among living birds, southern cassowaries are among the largest in the world, lighter on average only than ostriches.

An adult has stiff, bristly black plumage, a blue face, a long neck marked with red on the cape, and two red wattles hanging from the throat that can reach 18 cm (7.1 in) long. On top of the head sits a horn-like brown casque measuring 13 to 20 cm (5.1 to 7.9 in) high, and the bill ranges from 9.8 to 19 cm (3.9 to 7.5 in). Plumage looks the same in both sexes, but females are dominant, larger, and carry a longer casque, a bigger bill, and more vividly colored bare skin. Chicks start out with soft, fuzzy, striped plumage that darkens as the bird matures into the glossy black coat of an adult.

The feet are three-toed, thick, and powerful, armed on the inner toe with a dagger-like claw up to 12 cm (4.7 in) long. Typically the bird stands 1.5 to 1.8 m (4.9 to 5.9 ft) tall, though the largest documented individuals have reached around 85 kg (187 lb) and 2 m (6 ft 6.5 in). Males run lighter than females, weighing 29.2 to 55 kg (64 to 121 lb) against a female range of 46.7 to 76 kg (103 to 168 lb) — with historical specimens shot in Queensland between 1870 and 1894 reportedly reaching even greater weights, up to 263 lb (119 kg) by one account. Despite its bulk, the southern cassowary can run up to 50 km/h (31 mph), jump nearly 2 m (6.6 ft) vertically, and swim strongly enough to cross rivers and streams. In 2026, scientists discovered that the casques of southern cassowaries glow under ultraviolet light, in patterns distinct from those of northern cassowaries.

Behavior and diet

Southern cassowaries forage on the forest floor for fallen fruit and seeds, and they're able to safely digest some fruits and seeds that are toxic to other animals. Their diet also includes fungi, insects, other invertebrates such as snails, small vertebrates like fish, frogs, small birds, their eggs and nestlings, small mammals, and carrion. When food runs short, both wild and captive birds have been observed eating earth, possibly to obtain minerals otherwise missing from their diet. Examination of droppings shows the birds regularly eat fruit from the Davidsonia, Syzygium, palm, quandong, laurel, and myrtle families.

The species is largely solitary, coming together only to pair up during the breeding season in late winter or spring, though timing is highly variable. The male builds the nest — a mat of herbaceous plant material 5 to 10 cm (2–4 in) thick and up to 100 cm (39 in) wide, thick enough to drain moisture away from the eggs — and takes over incubation and chick-rearing entirely on his own. A clutch runs three to five eggs, each 11.8 to 15.8 cm (4.6 to 6.2 in) long and 8.2 to 10.2 cm (3.2 to 4.0 in) wide, weighing around 567 to 634 g (1.25 to 1.4 lb); the eggs start out bright pea-green and fade as they age. Incubation takes about 50 days. Chicks hatch precocial — fully feathered and able to move within hours — and depend entirely on the male, becoming independent at 9 to 12 months old. It takes 4 to 5 years for the casque and adult plumage to fully develop, which is also roughly when successful breeding begins. During mating season the birds make a thunderous call, along with hissing and rumbling otherwise; chicks use high-pitched contact whistles and chirps to call the male.

Range and habitat

The southern cassowary lives in Indonesia, Papua New Guinea, and northeastern Australia, mainly in tropical rainforest, though it will also make use of nearby savanna forest or mangrove stands. It favors lower elevations, generally staying below 1,100 m (3,600 ft) in Australia and below 500 m (1,600 ft) in New Guinea.

Conservation status

Globally, the IUCN evaluated the southern cassowary as Least Concern in 2018, with an occurrence range of about 396,000 km2 (153,000 sq mi) and a 2002 estimate of 10,000 to 20,000 birds worldwide, including 1,500 to 2,500 in Australia. The picture is more serious within Australia specifically, where the population is listed as Endangered under federal legislation, and where a 2023 draft recovery plan put the national count at around 5,000 individuals. Habitat loss from logging, road-building, feral animals preying on eggs, and vehicle strikes are among the main threats; in Queensland, a trial using AI to detect cassowaries near roadways and trigger warning signs may have cut fatal collisions by as much as a third, though the effect may be partly explained by a concurrent speed-limit reduction. A 2023 study found the species had recovered enough that it no longer met the criteria for a threatened listing under Australian federal law, citing stabilizing or slowly declining populations tied to expanded habitat protection.