Colours of Wildlife: Emu

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Emu

Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"

Emu by Willem.


Today we look at one of the world's most impressive bird species, the Emu, Dromaius novaehollandiae. The name means 'fast-runner from New Holland' (an old name for a part of Australia). This is the world's second-largest bird after the Ostrich. Females average taller and heavier than males, reaching a height of 190 cm/6'3" and a weight of 55 kg/121 lbs. They are rivalled in weight by the Southern and Northern Cassowaries, which I'll also feature here soon.


In fact, emus are the closest living relatives of the cassowaries. Both are classified in the same suborder, the Casuarii (sometimes raised to the rank of an order, the Casuariiformes) of the order of the large flightless birds, the Struthioniformes. These birds are also called the 'ratites', after their flat, raft-like breast bones, lacking the keels that anchor the massive chest muscles of flying birds. Emus are today found over most of Australia, in a variety of habitats, avoiding only the most barren deserts and the densest forests. While only a single form survives, three more existed in the recent past. On King Island, off Tasmania, there was a unique kind of emu Emu that no longer exists; it was either a full species, or a subspecies. Tasmania itself held another kind of emu, also extinct, while the third extinct form was on Kangaroo Island. There is very little known about these extinct emus, with today only a few bones and skins left. They were all somewhat smaller than the mainland emu, and likely differed in aspects of plumage and bare skin coloration too.

Emu by Willem.


In shape, an emu is much like an ostrich, except for a somewhat more horizontal stance. While ostriches have only two toes per foot, emus have three. With their long legs, they can march over long distances at a sustained speed of around 7 km/h (4.4 mph) or run for short distances at up to 48 km/h (30 mph) taking strides over 2.7 m/9' in length. Emus can even swim, in lakes, rivers or the ocean. A swimming emu seen from a distance might be mistaken, by someone not prepared for the idea of an aquatic ratite, for that weird Australian cryptid, the Bunyip. Emus have very small wings that can usually not even be seen, but when they are very hot, they will raise their wings to expose the bare skin underneath. Water evaporating from the skin surface then cools the emu down. They also pant to cool down. On cold days, the complex folds in their nasal passages help them to warm inhaled air; these also help to conserve body moisture. Emus can maintain a constant body temperature with outside temperatures varying from -5 to 45 degrees Celsius/23 to 113 degrees Fahrenheit.


The plumage of the emu is long and loose, more like hairs than like feathers. Actually each feather consists of two long, narrow shafts, unlike in any other birds except cassowaries. They're coarse and don't have interlocking barbs that give typical bird feathers their neat and streamlined appearance. The feathers hang down the emu's sides from a conspicuous 'parting' along the midline of the back. The body is brownish (but darker, almost black, directly after moulting) and the feathers on the head and neck are blackish. During the breeding season, the female has more black on her head than the male, and her bare facial skin is more intensely blue.


Ordinarily, emus are not very social. They occur singly or in pairs, or sometimes in groups of four to nine. When food and water is abundant in a region, larger congregations might form, as may also happen when birds move en masse in response to factors like rainfall and food abundance. Sometimes birds may intrude too much on each other's space, in which case one may threaten the other with neck stretched forwards and uttering a grunting sound. If not heeded, these warnings may turn into overt violence like pecks or kicks. The male may be aggressive also during the breeding display. Apart from the grunt, breeding birds also make a deep booming call. This is made possible by a large pouch in the lower airway, which can be inflated to a diameter of 30 cm/12". The sound also resonates in air sacs around the neck. Females make a particularly loud boom that can be heard 2 km/1.25 miles away. The female also makes a low boom, called 'drumming', during the breeding season.


Like ostriches, emus are omnivorous and will eat plants and small animals. They swallow stones to help grind down food items in their stomach. They will even eat their own half-digested droppings, a strategy to conserve water and extract more nutrition from their food. Captive emus have eaten glass shards, marbles, metal nuts and bolts, car keys and jewellery. Even in the desert, they will feed during the heat of the day. They need moisture to help keep themselves cool and will drink surface water (if available) once a day, or twice a day in the summer. But they can survive without drinking for several days by eating succulent plants. They can go without food for some days also. Young birds are more vulnerable to dehydration than adults are.

Doting Dads


Emus have an unusual breeding system. At the start of the season, in summer (December or January in the southern hemisphere) the females start giving their drumming calls, presumably to attract mates. Males will start building nests in their own territories. Females might fight each other over a mate. Once the female makes her choice, they will copulate; she lays her eggs in his nest, and then leaves. This happens by autumn to winter. Sometimes she will then mate with one or more other males, laying eggs in their nests also. This is called 'successive polyandry'. In each nest she can lay 5 to 15 eggs, spaced about two four days apart. The eggs are dark green. Actually, many nests will contain the eggs of more than one male. But just the male who built the nest incubates the eggs. He may stand up from time to time to turn the eggs, to trim the nest, or to preen himself, but never leaves the vicinity of the nest. Over this entire period, which lasts about eight weeks, he will not feed or drink at all! To enable him to do this, he will, before the incubation starts, eat as much as he can and put on fat, so that he has resources in his own body to feed on. But he also, while incubating, allows his body to go into a kind of torpor, reducing his temperature by 3 to 4 degrees Celsius, which means that he loses much less water, and conserves his energy.


The chicks hatch covered in down, with neat cream and brown stripes lengthwise down their bodies. They weigh about half a kilogram/one pound. They can walk within a few hours of hatching. They leave the nest after two to seven days, accompanying their dad. He is very aggressive and will chase away predators, people, and other emus, even the chicks' own mom. The chicks are vulnerable to predators like dingoes, foxes and birds of prey. But they soon grow big enough to fend for themselves. At five months, the bond between the chicks and the father starts to fray and they start moving around more independently. Typically, the male still remains with them for a few more months, in some cases up until they're 18 months old. They look adult at the age of one year, but become sexually mature at two to three years. They can live for more than ten years.

The Great Emu War

Emus by Willem.


When Europeans reached Australia, there were initial conflicts with the emus since the humans wanted to start farming the land the emus were living on. In one initiative, after World War 1, the government gave land to some of the soldiers who had served, in Western Australia. Their farms happened to be in a region to which emus migrated after having bred in the continent's interior. The emus learnt to break into the fields, eating the crops and even damaging the fences, allowing rabbits to enter and cause more crop destruction. By 1932, the problem was seen as so serious that the Australian army was called in. The plan was to kill about 20 000 emus; the tactics for doing this was to chase the emus to fence lines and then along them until they were cornered, and then to mow them down with machine guns. The emus however had tactics of their own. They were often hard to spot, and if shot at, groups broke up and individuals scattered and ran off at great speed. Pursuing them by truck over the uneven terrain was difficult and aiming at them almost impossible. Emus also turned out to be amazingly resilient, apparently 'absorbing' heavy fire without serious injury. In the end, the army managed to kill about a thousand emus, while some others were said to have died later from injuries. The war effort was finally abandoned as being ineffective. The problem was eventually largely solved by farmers building taller and stronger fences to keep the emus out.


These days, there are many emus all over the world, since they're easy to keep in captivity. Here you see a few kept on a farm by my friend Johann Engelbrecht. In Australia, emus now benefit from farming through the provisioning of water to cattle and sheep – which emus also make use of – and the erection of fences to keep predators out over large areas. Emus themselves are sometimes farmed chiefly for their meat, oil (often used as a nutritional supplement) and leather. Wild emus are given legal protection, and currently may number over seven hundred thousand individuals. All in all, the species can be considered safe.

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