Emu
From Wikipedia, the free encyclopedia
| Emu | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 |
||||||||||||||
| Conservation status | ||||||||||||||
| Scientific classification | ||||||||||||||
|
||||||||||||||
| Binomial name | ||||||||||||||
| Dromaius novaehollandiae (Latham, 1790) |
||||||||||||||
 The Emu has been recorded in the areas shown in pink.
|
||||||||||||||
| Synonyms | ||||||||||||||
|
Dromiceius novaehollandiae |
The Emu (pronounced /ˈiːmjuː/[1][2]), Dromaius novaehollandiae, is the largest bird native to Australia and the only extant member of the genus Dromaius. It is also the second-largest extant bird in the world by height, after its ratite relative, the ostrich. The soft-feathered, brown, flightless birds reach up to 2 m (6.5 ft) in height. The Emu is common over most of mainland Australia, although it avoids heavily populated areas, dense forest and arid areas. Emus can travel great distances at a fast, economical trot and, if necessary, can sprint at 50 km/h (30 mph) for some distance at a time.[3] They are opportunistically nomadic and may travel long distances to find food; they feed on a variety of plants and insects.
The Emu subspecies that previously inhabited Tasmania became extinct after the European settlement of Australia in 1788; and the distribution of the mainland subspecies has been influenced by human activities. Once common on the east coast, Emu are now uncommon; by contrast, the development of agriculture and the provision of water for stock in the interior of the continent have increased the range of the Emu in arid regions. Emus are farmed for their meat, oil and leather.
Contents |
Taxonomy and distribution
The Emu was first described under the name of the New Holland Cassowary in Arthur Phillip's Voyage to Botany Bay, published in 1789.[4] The species was named by ornithologist John Latham, who collaborated on Phillip's book and provided the first descriptions of and names for many Australian bird species; its name is Latin for "fast-footed New Hollander". The etymology of the common name Emu is uncertain, but is thought to have come from an Arabic word for large bird that was later used by Portuguese explorers to describe the related Cassowary in New Guinea.[5] In Victoria, some terms for the emu were Barrimal in the Djadja wurrung language, myoure in Gunai, and courn in Jardwadjali.[6] It was known as murawung or birabayin to the local Eora and Darug inhabitants of the Sydney basin.[7]
In his original 1816 description of the Emu, Vieillot used two generic names; first Dromiceius, then Dromaius a few pages later. It has been a point of contention ever since which is correct; the latter is more correctly formed, but the convention in taxonomy is that the first name given stands, unless it is clearly a typographical error.[8] Most modern publications, including those of the Australian government,[9] use Dromaius, with Dromiceius mentioned as an alternative spelling.
Classification
The Emu is classified in the family with their closest relatives the cassowaries in the family Casuariidae in the ratite order Struthioniformes. However an alternate classification has been proposed splitting the Casuariidae into their own order Casuariformes.
Three different Dromaius species were common in Australia before European settlement, and one species is known from fossils. The small emus — Dromaius baudinianus and D. ater — both became extinct shortly after; however, the Emu, D. novaehollandiae, remains common. The population varies from decade to decade, largely dependent on rainfall; it is estimated that the Emu population is 625,000–725,000, with 100,000–200,000 in Western Australia and the remainder mostly in New South Wales and Queensland.[5] D. novaehollandiae diemenensis, a subspecies known as the Tasmanian Emu, became extinct around 1865. Emus were introduced to Maria Island off Tasmania and Kangaroo Island near South Australia during the 20th century. The Kangaroo Island birds have established a breeding population there. The Maria Island population became extinct in the mid-1990s.
There are three extant subspecies in Australia:
- In the southeast, D. novaehollandiae novaehollandiae, with its whitish ruff when breeding;
- In the north, D. novaehollandiae woodwardi, slender and paler; and
- In the southwest, D. novaehollandiae rothschildi, darker, with no ruff during breeding.
Description
Emus are large birds. The largest can reach up to two metres (6 ft 7 inches) in height (1–1.3 metres (3.2–4.3 ft) at the shoulder). Emus weigh between 30 and 60 kilograms (66–132 pounds).[10][11]
They have small vestigial wings and a long neck and legs. Their ability to run at high speeds is due to their highly specialised pelvic limb musculature. Their feet have only three toes and a similarly reduced number of bones and associated foot muscles; they are the only birds with gastrocnemius muscles in the back of the lower legs. The pelvic limb muscles of Emus have a similar contribution to total body mass as the flight muscles of flying birds.[12]