The southern cassowary (Casuarius casuarius), also known as double-wattled cassowary, Australian cassowary, or two-wattled cassowary, is a large flightless 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.
The Australian population is listed as Endangered under federal and Queensland state legislation.
Presently, most authorities consider the southern cassowary monotypic, but several subspecies have been described.[1] 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.[1]
Cassowaries are most closely related to the kiwis, both families diverging from a common ancestor approximately 40 million years ago.[1]
The binomial name Casuarius casuarius is derived from its Malay name kesuari.[2] The southern cassowary was first described by Carl Linnaeus, in his 18th-century work Systema Naturae, as Struthio casuarius,[3] 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.[4]
The southern cassowary has been described under a large number of scientific names, all of which are now considered taxonomic synonyms for the species.[5]
| Synonyms | |
|---|---|
| Struthio casuarius Linnaeus 1758 | |
| Casuarius casuarius altijugus Sclater 1878 | |
| Casuarius altijugus Sclater 1878 | |
| Casuarius casuarius aruensis Schlegel 1866 | |
| Casuarius aruensis Schlegel 1866 | |
| Casuarius australis Wall 1854 | |
| Casuarius casuarius beccarii Sclater 1875 | |
| Casuarius beccarii Sclater 1875 | |
| Casuarius bicarunculatus Sclater 1860 | |
| Casuarius casuarius bicarunculatus Sclater 1860 | |
| Casuarius bistriatus van Oort 1907 | |
| Casuarius casuarius bistriatus van Oort 1907 | |
| Casuarius casuarius casuarius Linnaeus 1758 | |
| Casuarius casuarius chimaera Rothschild 1904 | |
| Cassowara eximia Perry 1811 | |
| Casuarius casuarius grandis Rothschild 1937 | |
| Casuarius galeatus Bonnaterre 1790 | |
| Casuarius casuarius hamiltoni Mathews 1915 | |
| Casuarius casuarius intensus Rothschild 1898 | |
| Casuarius bicarunculatus intermedius Rothschild 1928 | |
| Casuarius casuarius intermedius Rothschild 1928 | |
| Casuarius casuarius johnsonii Müller 1866 | |
| Casuarius johnsonii Müller 1866 | |
| Casuarius casuarius lateralis Rothschild 1925 | |
| Casuarius casuarius salvadorii Oustalet 1878 | |
| Casuarius salvadorii Oustalet 1878 | |
| Casuarius casuarius sclaterii Salvadori 1878 | |
| Casuarius sclaterii Salvadori 1878 | |
| Casuarius casuarius tricarunculatus Beccari 1876 | |
| Casuarius bicarunculatus tricarunculatus Beccari 1876 | |
| Casuarius tricarunculatus Beccari 1876 | |
| Casuarius casuarius violicollis Rothschild 1899 | |
| Hippalectryo indicus Gloger 1842 | |
| Casuarius hagenbecki Rothschild 1904 |
The southern cassowary has stiff, bristly black plumage, a blue face and a long neck, red on the cape and two red wattles measuring around 17.8cm (07inches) in length hanging down around its throat. A horn-like brown casque, measuring 13to high, sits atop the head. The bill can range from 9.8to. The plumage is sexually monomorphic, but the female is dominant and larger with a longer casque, larger bill and brighter-coloured bare parts. The juveniles have brown longitudinal striped plumage.
The three-toed feet are thick and powerful, equipped with a lethal dagger-like claw up to 12cm (05inches) on the inner toe. It is perhaps the largest member of the cassowary family and is tied as the third heaviest bird on earth (after the Somali ostrich and the common ostrich), at a maximum size estimated at 85kg (187lb) and tall. Normally, this species ranges from in length. The height is normally ; females average 58.5kg (129lb), while males average 29to(-). The northern cassowary is about the same size on average and is perhaps very mildly less sexually dimorphic than the southern. Most adult birds will weigh between 17and.[6] It is technically the largest Asian bird (since the extinction of the Arabian ostrich) and the largest Australian bird (though the emu may be slightly taller).
The southern cassowary is distributed in Indonesia, Papua New Guinea, and northeastern Australia.[7] It mainly inhabits tropical rainforests but may make use of nearby savannah forests or mangroves stands. The species prefers elevations below 1100m (3,600feet) in Australia, and 500m (1,600feet) on New Guinea.
, according to Birdlife International, the breeding populations were as follows:
| Location | Population | Trend | |
|---|---|---|---|
| Unknown | Declining | ||
| Seram, Indonesia | Unknown | Unknown | |
| Aru Islands, Indonesia | Unknown | Unknown | |
| Northeastern Australia | 1,500 to 2,500 | Declining | |
| Paluma Range, Qld, Australia | Unknown | Declining | |
| McIlwraith Range, Qld, Australia | 1,000+ | Declining | |
| Apudthama National Park, Qld, Australia | Unknown | Unknown | |
| Total | 4,000+ | Declining |
Southern cassowaries forage on the forest floor for fallen fruit and are capable of safely digesting some fruits toxic to other animals. They also eat fungi, and some insects and small vertebrates. Inspection of the faeces reveals that commonly ingested fruits are Davidsonia pruriens, Syzygium divaricatum, and members of the laurel family (Lauraceae).[8]
The southern cassowary is a solitary bird, which pairs only in breeding season, in late winter or spring. The male builds a nest on the ground, a mattress of herbaceous plant material 5to(-) thick and up to 100cm (00inches) 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 or four eggs are laid measuring 138mm95mm. They have a granulated surface and are initially bright pea-green in colour although they fade with age.[9] 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.
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.[10]
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 and 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.[11]
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.[12]
Being fed by people tempts southern cassowaries into closer associations with human-inhabited areas, increasing the already high risk of vehicle strikes – a major cause of southern cassowary mortality – and increasing the likelihood of encounters with humans.[13] Many "aggressive" birds are simply responding to having been fed by humans in the past. Unfortunately the poor reputation of this species leads to confusion and misinformation among the public, which hampers conservation efforts of this shy bird.
In a 2017 Australian Birdlife article, Karl Brandt suggested Aboriginal encounters with the southern cassowary may have inspired the myth of the bunyip.[14]
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 396000km2, and between 10,000 and 20,000 birds were estimated in a 2002 study, with between 1,500 and 2,500 in Australia.
The Australian population is listed as Endangered under federal (EPBC Act). Under the Nature Conservation (Animals) Regulation 2020 (Queensland), November 2022 list, the northern population is considered vulnerable, while the southern population remains as endangered. A draft recovery plan to save the species was published by the federal government in June 2023, at which time there were estimated to be around 5,000 individuals in Australia.[15] A study published in Biological Conservation in March 2023 listed 23 species which the authors considered to no longer meet the criteria as threatened species under the EPBC Act, including the Southern cassowary. A 2021 study had shown that extensive reservation had led to recovery of the species, and legislation had prevented the previously rapid loss of habitat. The reason for their assessment was given as "Populations now stable or declining at a rate less than threshold".[16] The team, led by John Woinarski of Charles Darwin University looked at all species listed as threatened under the act in 2000 and 2022.[17]
Southern cassowaries have been bred in zoos around the world, including White Oak Conservation in Yulee, Florida, United States.[18]