Casuarius

Casuarius is a genus of Casuariiformes birds of the family Casuariidae known as cassowaries. It is composed of three species that are distributed in Australia and New Guinea. They are solitary flightless and very aggressive birds that live in the tropical rain forest, where they feed on fallen fruits, some fungi and small animals. Its black plumage is made up of rough hornbills, some of which end in hair-like filaments. The neck is blue and red (caruncle) and they have a large bony protuberance on the head, called a helmet, which can give the bird protection at times when the animal moves through the dense vegetation of its habitat, it can also be used as a defense at some point when you feel threatened.

The female can mate with several males, building a clutch with each of them. They lay their eggs in a bed of leaves on the wooded ground. The chicks are cared for by the parents for nine months. The male takes over the incubation for about fifty-two days, but both parents care for the young.

Lifestyle

Behavior

Cassowaries are shy birds that live deep in the jungle and often fly away before a human notices their presence. Due to their secretive lifestyle, cassowaries are not sufficiently studied. They are crepuscular and nocturnal, with peaks of activity at dawn and dusk. During the day they rest sedentarily. They spend most of their time searching for food. In doing so, they cut pathways through the undergrowth, which they then use again and again.

Aside from the breeding season, cassowaries are solitary and territorial animals. Cassowaries emit low frequency sounds, up to 23 hertz, which can be used to communicate. Low-frequency sounds are not muffled even over long distances, so they would be a suitable means of communication in dense jungle. The helmet may be adequate to pick up those low sounds. However, at present, cassowary function and intraspecific communication in cassowaries are not sufficiently studied to draw definitive conclusions.

Especially when cassowaries have young or feel cornered, they can react extremely aggressively. An attack is often preceded by threatening gestures in which the feathers rise and the head bows to the ground, the neck swells, and the body begins to shake. If an attack occurs, the cassowary kicks with both legs at the same time. The dagger-like claw can inflict the most serious wounds; there have even been deaths, but they are rare.

Playback

Egg, Wiesbaden Museum Collection.

The exact reproductive period of each species is unknown. Most populations appear to breed between June and October, but breeding birds have been found at any time of the year. The males guard a territory of one to five square kilometers. When a female enters the territory, the male begins courtship. The plumage stands erect and the female circles slowly; her neck inflates, shining with special intensity, and a & # 34; boo-boo-boo & # 34; off.

After mating, the pair stays together for a few weeks. The female lays three to five eggs in a nest prepared by the male. The eggs are quite large and can weigh up to 650 grams. After laying, the female leaves the nest. She often goes to another male's territory to mate with him. The male is left alone with the clutch and is in charge of breeding and rearing.

After 49 to 56 days of incubation, the hatchlings hatch. They have light brown plumage with darker stripes along the body. The young can run within hours of birth and follow their father for about nine months. Before they are half a year old, they put on the plain brown youth dress; At about the same time, the helmet begins to be visible. During their second year of life, cassowaries gradually take on the appearance of adult birds and reach their size. At three and a half years old, cassowaries are sexually mature.

Little is known about the potential length of life. Estimates range from twelve to nineteen years old in the wild. At the zoo, however, the cassowaries have reached an age of 40 years.

Diet

Cassowaries feed mainly on fruit, which they pick up from the ground or pluck from lower branches. They also eat mushrooms, insects, frogs, snakes, and other small animals. Like other ratites, cassowaries swallow stones, which serve as gastroliths in the stomach to break down food. They drink regularly; water is usually abundant in their habitats.

Predators

New Guinea cassowaries have no natural predators.

Distribution and habitat

Cassowaries live in the tropical forests of New Guinea and Queensland. New Guinea is the main distribution area. All three species inhabit similar habitats, but often avoid meeting because they prefer different altitudes. Thus, the single-lobed cassowary lives mainly in lowland forests, the helmeted cassowary at mid-altitudes, and the Bennett's cassowary in moist montane forests. However, the habitats overlap and there are no clear dividing lines; in areas where the other species do not occur, the Bennett's cassowary also descends to sea level. Since they depend on fruit throughout the year, they can only survive in large forests that have a high diversity of species.

Australia also appears to have been inhabited by cassowaries in the Pleistocene. At present, only the helmeted cassowary lives on the Cape York Peninsula in north Queensland. Here, too, the cassowaries are pure inhabitants of the forests; the fact that they are occasionally seen in the fields is due to the fact that the increasing destruction of the forests forces them to cross these open areas.

In addition, cassowaries live on some of New Guinea's neighboring islands: the helmeted cassowary on Seram and the Aru Islands, the Bennett's cassowary on New Britain and Yapen, and the single-lobed cassowary on Yapen and Salawati. However, it is not clear if these were native to there or if their appearance is the result of trade in young birds by the inhabitants of New Guinea.

Systematics and evolution

While the phylogenetic relationships of the rest of the paleognaths have not yet been clarified, both molecular and morphological studies agree that cassowaries form a clade with emus. On the other hand, the position of this group with respect to to the other paleognaths varies according to studies of molecular data (which establish the clade as the sister group to kiwis) and morphological data.

• Casuarius Brisson, 1760
  • Casuarius casuarius (Linnaeus), 1758
  • Casuarius benetti Gould, 1858
  • Casuarius unppendiculatus Blyth, 1860
  • Casuarius lydekkeri Rothschild, 1911 †