The southern cassowary (Casuarius casuarius), also known as 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 is one of the three living species of cassowary, alongside the dwarf cassowary and the northern cassowary. It is a ratite and therefore related to the emu, ostrich, rhea and kiwi. Southern cassowaries are among the largest birds in the world, only weighing less than ostriches.
The Australian population is listed as Endangered under federal and Queensland state legislation.
Taxonomy Presently, most authorities consider the southern cassowary monotypic, but several subspecies have been described. It has proven very difficult to confirm the validity of these due to individual variations, age-related variations, the relatively few available specimens (and the bright skin of the head and neck – the basis upon which several subspecies have been described – fades in specimens), and that locals are known to have traded live cassowaries for hundreds, if not thousands of years, some of which are likely to have escaped/been deliberately introduced to regions away from their origin.
Cassowaries are the sister lineage of emus, both being in the family casuariidae.
The binomial name Casuarius casuarius is derived from its Malay name kesuari. The southern cassowary was first described by Carl Linnaeus, in his 18th-century work Systema Naturae, as Struthio casuarius, from a specimen from Seram, in 1758. It is now the type species of the genus Casuarius. Common names for the species include southern cassowary, double-wattled cassowary, Australian cassowary, and two-wattled cassowary.
The southern cassowary has been described under a large number of scientific names, all of which are now considered taxonomic synonyms for the species.
SynonymsStruthio casuarius Linnaeus 1758Casuarius casuarius altijugus Sclater 1878Casuarius altijugus Sclater 1878Casuarius casuarius aruensis Schlegel 1866Casuarius aruensis Schlegel 1866Casuarius australis Wall 1854Casuarius casuarius beccarii Sclater 1875Casuarius beccarii Sclater 1875Casuarius bicarunculatus Sclater 1860Casuarius casuarius bicarunculatus Sclater 1860Casuarius bistriatus van Oort 1907Casuarius casuarius bistriatus van Oort 1907Casuarius casuarius casuarius Linnaeus 1758Casuarius casuarius chimaera Rothschild 1904Cassowara eximia Perry 1811Casuarius casuarius grandis Rothschild 1937Casuarius galeatus Bonnaterre 1790Casuarius casuarius hamiltoni Mathews 1915Casuarius casuarius intensus Rothschild 1898Casuarius bicarunculatus intermedius Rothschild 1928Casuarius casuarius intermedius Rothschild 1928Casuarius casuarius johnsonii Müller 1866Casuarius johnsonii Müller 1866Casuarius casuarius lateralis Rothschild 1925Casuarius casuarius salvadorii Oustalet 1878Casuarius salvadorii Oustalet 1878Casuarius casuarius sclaterii Salvadori 1878Casuarius sclaterii Salvadori 1878Casuarius casuarius tricarunculatus Beccari 1876Casuarius bicarunculatus tricarunculatus Beccari 1876Casuarius tricarunculatus Beccari 1876Casuarius casuarius violicollis Rothschild 1899Hippalectryo indicus Gloger 1842Casuarius hagenbecki Rothschild 1904
Description
The adult southern cassowary has stiff, bristly black plumage, a blue face and a long neck, red on the cape and two red wattles measuring up to in length hanging down around its throat. A horn-like brown casque, measuring high, sits atop the head. The bill can range from . The plumage is sexually monomorphic, but the female is dominant and larger with a longer casque, larger bill and brighter-coloured bare parts. Plumage of the southern cassowary develops as it grows, juveniles with soft, fuzzy and striped plumage for the first few months. Immature birds are covered in hair-like brown plumage, and as they grow, the feathers darken.
The three-toed feet are thick and powerful, equipped with a lethal dagger-like claw up to on the inner toe. Southern cassowaries are among the largest living birds, only being lighter on average than ostriches, the largest contemporary individuals have been recorded around and tall. Typically, the bird stands in height. Male southern cassowaries are lighter than the females, weighing between . Adult female birds can weigh from to .
From 1870 to 1894, Archibald Meston, Robert Johnstone, and others had shot, weighed, and documented southern cassowaries in Queensland that far exceeded typical mass. These specimens ranged in mass from .CARDWELL. (1870, September 24). Mackay Mercury and South Kennedy Advertiser (Qld. : 1867 - 1887), p. 3. Retrieved July 8, 2026, from http://nla.gov.au/nla.news-article169702229CASSOWARY SHOOTING IN QUEENSLAND. (1870, July 27). Evening News (Sydney, NSW : 1869 - 1931), p. 4. Retrieved July 8, 2026, from http://nla.gov.au/nla.news-article107134179 In 1889, Meston claimed the specimen shot by John Nairne was weighed at , saying it was probably the largest ever killed.INTERCOLONIAL. (1889, September 28). Leader (Melbourne, Vic. : 1862 - 1918, 1935), p. 16. Retrieved July 8, 2026, from http://nla.gov.au/nla.news-article198057028 He later cited the figure as and .Field Shooting in Queensland. (1891, February 14). The Boomerang (Brisbane, Qld. : 1887 - 1892), p. 6. Retrieved July 8, 2026, from http://nla.gov.au/nla.news-article293613832 Meston had written, "there is no reason to suppose that was the largest living specimen" in reference to this specimen.
With powerful legs, the southern cassowary can run at speeds of up to and jump nearly vertically. They are strong swimmers capable of moving across rivers and streams.
Research In 2026, scientists discovered that southern cassowary casques glow under ultraviolet light, and in different patterns than northern cassowary casques.
Range and habitat The southern cassowary is distributed in Indonesia, Papua New Guinea, and northeastern Australia. It mainly inhabits tropical rainforests but may make use of nearby savannah forests or mangroves stands. The species prefers elevations below in Australia, and in New Guinea.
, according to Birdlife International, the breeding populations were as follows: +Breeding population and trends Location Population TrendSouthern New Guinea Unknown DecliningSeram, Indonesia Unknown UnknownAru Islands, Indonesia Unknown UnknownNortheastern Australia 1,500 to 2,500 DecliningPaluma Range, Qld, Australia Unknown DecliningMcIlwraith Range, Qld, Australia 1,000+ DecliningApudthama National Park, Qld, Australia Unknown UnknownTotal 4,000+ Declining
Diet
Southern cassowaries forage on the forest floor for fallen fruit and seeds and are capable of safely digesting some fruits and seeds toxic to other animals. They also eat fungi, and some insects, other invertebrates (such as snails), small vertebrates (such as fish, frogs, small birds and their eggs and nestlings, and small mammals), and carrion. When food is scarce, both wild and captive cassowaries have been seen to ingest earth, perhaps seeking supplementary minerals. Inspection of the faeces reveals that commonly ingested fruits are Davidsonia pruriens, Syzygium divaricatum, and members of the palm (Arecaceae), quandong (Elaeocarpaceae), laurel (Lauraceae), and myrtle (Myrtaceae) families.
Behavior Southern cassowaries make a thunderous call during mating season, and hissing and rumblings otherwise. Chicks will make frequent high-pitched contact whistles and chirps to call the male.
Breeding
The southern cassowary is a solitary bird, which pairs only in breeding season, in late winter or spring (but highly variable). The male builds a nest on the ground, a mattress of herbaceous plant material thick and up to wide. This is thick enough to let moisture drain away from the eggs. The male also incubates the eggs and raises the chicks alone. A clutch of three to five eggs are laid measuring in length and in width, with a mass of around . They have a granulated surface and are initially bright pea-green in colour although they fade with age. The incubation period takes around 50 days.
Chicks hatch precocial, fully feathered, and able to move and explore within hours of hatching. Parental care is done solely by the male, who the chicks depend on for survival. Young birds typically become independent at 9–12 months of age. It will take around 4–5 years for the casque and adult plumage to fully develop, this is also the time in which successful breeding usually starts.
Interaction with humans
Southern cassowaries have a reputation for being dangerous to humans and other animals, and are often regarded as aggressive. The birds can jump quite high and kick powerfully with their blade-like claws. However, deadly encounters with southern cassowaries are rare. Only two human deaths have been reported since 1900. A 2003 historical study of 221 southern cassowary attacks showed that 150 had been against humans: 75% of these had been from southern cassowaries that had been fed by people, 71% of the time the bird had chased or charged the victim, 15% of the time they kicked. Of the attacks, 73% involved the birds expecting or snatching food, 5% involved defending their natural food sources, 15% involved defending themselves from attack, and 7% involved defending their chicks or eggs. Only one human death was reported among those 150 attacks.
The first documented human death caused by a southern cassowary was on 6 April 1926. In Australia, 16-year-old Phillip McClean and his brother, age 13, came across a southern cassowary on their property and decided to try to kill it by striking it with clubs. The bird kicked the younger boy, who fell and ran away as his older brother struck the bird. The older McClean then tripped and fell to the ground. While he was on the ground, the cassowary kicked him in the neck, opening a 1.25 cm (0.5 in) wound that may have severed his jugular vein. The boy died of his injuries shortly thereafter.
Another human death due to a southern cassowary was recorded in Florida, United States on 12 April 2019. The bird's owner, a 75-year-old man who had raised the animal, was apparently clawed to death after he fell to the ground.
Feeding by humans can draw cassowaries to human-inhabited areas, increasing the risk of vehicle strikes, a major cause of southern cassowary mortality, and increasing the likelihood of encounters with humans.
In a 2017 Australian Birdlife article, Karl Brandt suggested Aboriginal encounters with the southern cassowary may have inspired the myth of the bunyip.
Conservation Although subject to ongoing habitat loss (some due to logging), limited range, and overhunting in some areas, the southern cassowary was evaluated as Least concern in 2018 by the International Union for Conservation of Nature (IUCN). Other threats include feral animals eating their eggs and roadkill. Road-building, feral animals and hunting are the worst of these threats. It has an occurrence range of , and between 10,000 and 20,000 birds were estimated in a 2002 study, with between 1,500 and 2,500 in Australia.
The Queensland (Australia) Department of Transport and Main Roads trialed a system using AI to detect the presence of these birds near a roadway coupled with warning signs. This may have resulted in reduction in fatal accidents of as much as a third, though the data may have been confounded by a speed limit reduction around the same time.