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Emu

2007 Schools Wikipedia Selection. Related subjects: Birds

                       iEmu

                             Conservation status

   See text
            Scientific classification

   Kingdom: Animalia
   Phylum:  Chordata
   Class:   Aves
   Order:   Struthioniformes
   Family:  Casuariidae
   Genus:   Dromaius
   Species: D. novaehollandiae

                                Binomial name

   Dromaius novaehollandiae
   ( Latham, 1790)

                                  Synonyms

   Dromiceius novaehollandiae

   The Emu ( IPA pronunciation: [ˈiːmjuː]), Dromaius novaehollandiae, is
   the largest bird native to Australia and the only extant member of the
   genus Dromaius. It is also the second-largest bird in the world by
   height, after its ratite relative, the ostrich. The soft-feathered,
   brown, flightless birds reach up to 2 m (6 ft 7 in) 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 (31  mph) for some distance at a time. 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
   following the European settlement of Australia in 1788; the
   distribution of the mainland subspecies has also been affected by human
   activities. The Emu was once common on the east coast, but is now
   uncommon there; 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.

Taxonomy and distribution

   The Emu has been recorded in the black-coloured areas shown here.
   Enlarge
   The Emu has been recorded in the black-coloured areas shown here.

   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. D. novaehollandiae diemenensis, a
   subspecies known as the Tasmanian Emu, became extinct around 1865. Emus
   were introduced in Maria Island near Tasmania, and Kangaroo Island near
   South Australia, in the 20th century and have established breeding
   populations there.

   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.

   The species was first described under the name of the New Holland
   Cassowary in Arthur Phillip's Voyage to Botany Bay, published in 1789.
   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.

Physical description

   Emus have only three toes in a tridactyl arrangement; this adaptation
   for running is seen in other bird species, such as bustards and quails.
   The Ostrich has only two toes.
   Enlarge
   Emus have only three toes in a tridactyl arrangement; this adaptation
   for running is seen in other bird species, such as bustards and quails.
   The Ostrich has only two toes.

   Emus are large birds. The largest individuals can reach up to two
   metres (6 ft 7 in) in height (1–1.3 metres (3.2–4.3 ft) at the
   shoulder) and weigh between 30 and 45 kilograms (66–100 pounds). 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.

   Emus have brown to grey-brown plumage of shaggy appearance; the shafts
   and the tips of the feathers are black. Solar radiation is absorbed by
   the tips, and the loose-packed inner plumage insulates the skin. The
   resultant heat is prevented from flowing to the skin by the insulation
   provided by the coat, allowing the bird to be active during the heat of
   the day. A unique feature of the Emu feather is its double rachis
   emerging from a single shaft. The sexes are similar in appearance.

   On very hot days, Emus pant to maintain their body temperature, their
   lungs work as evaporative coolers and, unlike some other species, the
   resulting low levels of carbon dioxide in the blood do not appear to
   cause alkalosis. For normal breathing in cooler weather, they have
   large, multifolded nasal passages. Cool air warms as it passes through
   into the lungs, extracting heat from the nasal region. On exhalation,
   the Emu's cold nasal turbinates condense moisture back out of the air
   and absorb it for reuse.

Reproduction

   Emu chicks have distinctive bilateral stripes that help to camouflage
   them.
   Enlarge
   Emu chicks have distinctive bilateral stripes that help to camouflage
   them.

   Emus form breeding pairs during the summer months of December and
   January, and may remain together for about five months. Mating occurs
   in the cooler months of May and June. During the breeding season, males
   experience hormonal changes, including an increase in luteinizing
   hormone and testosterone levels, and their testicles double in size.
   Males lose their appetite and construct a rough nest in a
   semi-sheltered hollow on the ground from bark, grass, sticks and
   leaves. The pair mates every day or two, and every second or third day
   the female lays an average of 11 (and as many as 20) very large,
   thick-shelled, dark-green eggs. The eggs are on average 134 x 89
   millimeters (5.3 x 3.5 inches) and weigh between 700 and 900  grams
   (1.5–2 pounds), which is roughly equivalent to 10–12 chicken eggs in
   volume and weight. The first occurrence of genetically identical avian
   twins was demonstrated in the Emu.

   The male becomes broody after his mate starts laying, and begins to
   incubate the eggs before the laying period is complete. From this time
   on, he does not eat, drink or defecate, and stands only to turn the
   eggs, which he does about 10 times a day. Over eight weeks of
   incubation, he will lose a third of his weight and will survive only on
   stored body-fat and on any morning dew that he can reach from the nest.
   As with many other Australian birds, such as the Superb Fairy-wren,
   infidelity is the norm for Emus, despite the initial pair-bond: once
   the male starts brooding, the female mates with other males and may lay
   in multiple clutches; thus, as many as half the chicks in a brood may
   be fathered by others, or by neither parent as Emus also exhibit brood
   parasitism. Some females stay and defend the nest until the chicks
   start hatching, but most leave the nesting area completely to nest
   again; in a good season, a female Emu may nest three times.

   Incubation takes 56 days, and the male stops incubating the eggs
   shortly before they hatch. Newly hatched chicks are active and can
   leave the nest within a few days. They stand about 25 centimetres tall
   and have distinctive brown and cream stripes for camouflage, which fade
   after three months or so. The male stays with the growing chicks for up
   to 18 months, defending them and teaching them how to find food. Chicks
   grow very quickly and are full-grown in 12–14 months; they may remain
   with their family group for another six months or so before they split
   up to breed in their second season. In the wild, Emus live between 10
   to 20 years; captive birds can live longer than those in the wild.

Ecology and behaviour

   Emu eyes are golden brown to black. The naked skin on the neck is
   bluish-black.
   Enlarge
   Emu eyes are golden brown to black. The naked skin on the neck is
   bluish-black.

   Emus live in most habitats across Australia, although they are most
   common in areas of sclerophyll forest and savanna woodland, and least
   common in populated and very arid areas. Emus are largely solitary, and
   while they can form enormous flocks, this is an atypical social
   behaviour that arises from the common need to move towards food
   sources. Emus have been shown to travel long distances to reach
   abundant feeding areas. In Western Australia, Emu movements follow a
   distinct seasonal pattern — north in summer and south in winter. On the
   east coast their wanderings do not appear to follow a pattern. Emus are
   also able to swim when necessary.

   Their calls consist of loud booming, drumming and grunting sounds that
   can be heard up to two kilometres away. The booming sound is created in
   an inflatable neck sac.

   Emus forage in a diurnal pattern. They eat a variety of native and
   introduced plant species; the type of plants eaten depends on seasonal
   availability. They also eat insects, including grasshoppers and
   crickets, ladybirds, soldier and saltbush caterpillars, Bogong and
   cotton-boll moth larvae and ants. In Western Australia, food
   preferences have been observed in travelling Emus: they eat seeds from
   Acacia aneura until it rains, after which they eat fresh grass shoots
   and caterpillars; in winter they feed on the leaves and pods of Cassia;
   in spring, they feed on grasshoppers and quandong fruit. Emus may serve
   as an important agent for the dispersal of large viable seeds, which
   could contribute to the maintenance of floral biodiversity.

Conservation status

   Emus were used as a source of food by indigenous Australians and early
   European settlers. Aborigines used a variety of techniques to catch the
   bird, including spearing them while they drank at waterholes, poisoning
   waterholes, catching Emus in nets, and attracting Emus by imitating
   their calls or with a ball of feathers and rags dangled from a tree.
   Europeans killed Emus to provide food and to remove them if they
   interfered with farming or invaded settlements in search of water
   during drought. An extreme example of this was the Emu War in Western
   Australia in 1932, when Emus that flocked to Campion during a hot
   summer scared the town’s inhabitants and an unsuccessful attempt to
   drive them off was mounted. In John Gould's Handbook to the Birds of
   Australia, first published in 1865, he laments the loss of the Emu from
   Tasmania, where it had become rare and has since become extinct; he
   notes that Emus were no longer common in the vicinity of Sydney and
   proposes that the species be given protected status. Wild Emus are
   formally protected in Australia under the Environment Protection and
   Biodiversity Conservation Act 1999.

   Although the population of Emus on mainland Australia is thought to be
   higher now than before European settlement, some wild populations are
   at risk of local extinction due to small population size. Threats to
   small populations include the clearance and fragmentation of areas of
   habitat; deliberate slaughter; collisions with vehicles; and predation
   of the young and eggs by foxes, feral and domestic dogs, and feral
   pigs. The isolated Emu population of the New South Wales North Coast
   Bioregion and Port Stephens is listed as endangered by the New South
   Wales Government.

Uses of Emu

   The Emu was an important source of meat to the Aborigines in the areas
   to which it was endemic. The Emu fat was used as bush medicine, and was
   rubbed on the skin. It also served as a valuable lubricant. It was
   mixed with ochre to make the traditional paint for ceremonial body
   adornment, as well as to oil wooden tools and utensils such as the
   coolamon.

   An example of how the Emu was cooked come from the Arrernte of Central
   Australia who call it Kere ankerre:

     Emus are around all the time, in green times and dry times. You
     pluck the feathers out first, then pull out the crop from the
     stomach, and put in the feathers you've pulled out, and then singe
     it on the fire. You wrap the milk guts that you've pulled out into
     something [such as] gum leaves and cook them. When you've got the
     fat off, you cut the meat up and cook it on fire made from river red
     gum wood.

   Farmed Emu at Virginia's Emu Marketing Cooperative near Warrenton,
   Virginia, US.
   Enlarge
   Farmed Emu at Virginia's Emu Marketing Cooperative near Warrenton,
   Virginia, US.

   Commercial Emu farming started in Western Australia in 1987 and the
   first slaughtering occurred in 1990. In Australia, the commercial
   industry is based on stock bred in captivity and all states except
   Tasmania have licensing requirements to protect wild Emus. Outside
   Australia, Emus are farmed on a large scale in North America, with
   about 1 million birds in the US, Peru and China, and to a lesser extent
   in some other countries. Emus breed well in captivity, and are kept in
   large open pens to avoid leg and digestive problems that arise with
   inactivity. They are typically fed on grain supplemented by grazing,
   and are slaughtered at 50–70 weeks of age. They eat two times a day,
   they prefer 5 pounds of leaves each meal.

   Emus are farmed primarily for their meat, leather and oil. Emu meat is
   a low-fat, low-cholesterol meat (85 mg/100 g); despite being avian, it
   is considered a red meat because of its red colour and pH value. The
   best cuts come from the thigh and the larger muscles of the drum or
   lower leg. Emu fat is rendered to produce oil for cosmetics, dietary
   supplements and therapeutic products. There is some evidence that the
   oil has anti-inflammatory properties; however, the US Food and Drug
   Administration regards pure emu oil product as an unapproved drug. Emu
   leather has a distinctive patterned surface, due to a raised area
   around the hair follicles in the skin; the leather is used in such
   small items as wallets and shoes, often in combination with other
   leathers. The feathers and eggs are used in decorative arts and crafts.
   Retrieved from " http://en.wikipedia.org/wiki/Emu"
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   with only minor checks and changes (see www.wikipedia.org for details
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