The emu is an unusual bird. She does not chirp, but grumbles; does not fly, but walks and runs at a speed of 50 km/h! These birds belong to a group of non-flying birds, the so-called runners (ratites). This is the oldest form of birds, including cassowaries, ostriches and rheas. Emus are the largest bird found in Australia and the second largest bird in the world.
They are most often found in forested areas and try to avoid densely populated areas. This means that emus are more aware of their environment than it seems at first glance. Although emus prefer to be in wooded or bushy areas where there is plenty of food and shelter, it is important for them to know what is going on around them.
View origin and description
The emu was first discovered by Europeans in 1696 when explorers visited western Australia. An expedition led by Captain Willem de Vlaming from Holland searched for the missing ship. The birds were first mentioned under the name “New Holland Cassowary” by Arthur Philip, traveling in Botany Bay in 1789.
The species was identified by ornithologist John Latham in 1790, modeled after the Australian region of Sydney, a country that was known at the time as New Holland. He provided the first descriptions and names of many Australian bird species. French ornithologist Louis Pierre Vieillot used two generic names in his original description of the emu in 1816.
The subject of what follows was the question of which name to use. The second is formed more correctly, but in taxonomy it is assumed that the first name given to the organism remains valid. Most current publications, including the Australian Government’s position, use Dromaius and mention Dromiceius as an alternative spelling.
The etymology of the name “emu” is not determined, but it is believed to come from the Arabic word for big bird. Another theory is that it comes from the word “ema”, which is used in Portuguese for a large bird, akin to an ostrich or a crane. Emu occupy a significant place in the history and culture of the aborigines. They inspire them to certain dance steps, are the subject of astrological mythology (the constellation of emus) and other historical creations.
Appearance and features
The emu is the second tallest bird in the world. The largest individuals can reach 190 cm. The length from tail to beak is from 139 to 164 cm, in males an average of 148.5 cm, and in females 156.8 cm. The emu is the fourth or fifth largest bird living today. Adult emus weigh between 18 and 60 kg. Females are slightly larger than males. Emus have three toes on each foot, which are specially adapted for running and are found in other birds such as bustards and quails.
Emus have vestigial wings, each with a small tip at the end. The emu flaps its wings while running, possibly as a means of stabilizing when moving quickly. They have long legs and neck, and the speed of movement is 48 km/h. The legs have a reduced number of bones and associated foot muscles, unlike other birds. When walking, the emu takes steps of about 100 cm, but at a full gallop, the stride length can reach 275 cm. The legs are devoid of feathers.
Like the cassowary, the emu has sharp claws that serve as the main defensive element and are used in combat to strike at the enemy. They have good hearing and vision, which allows them to detect threats in advance. A pale blue neck shows through the rare feathers. They have grey-brown shaggy plumage and black tips. The rays of the sun are absorbed by the tips, while the inner plumage insulates the skin. This prevents the birds from overheating, allowing them to be active during the heat of the day.
Fun Fact: The plumage changes color due to environmental factors, giving the bird a natural camouflage. Emu feathers in drier areas with red soils are rufous, while birds living in humid conditions tend to have darker hues.
The eyes of emus are protected by filamentous membranes . These are translucent secondary eyelids that move horizontally from the inner edge of the eye to the outer edge. They act as visors, protecting the eyes from the dust common in windy, dry regions. The emu has a tracheal pouch, which becomes more prominent during the mating season. With a length of more than 30 cm, it is quite spacious and has a thin wall and an opening 8 cm long.
Where does the emu live?
Emus are only found in Australia. These are nomadic birds and their distribution range covers most of the mainland. Emus were once found in Tasmania, but were destroyed by early European settlers. Two dwarf species that inhabited Kangaroo Island and King Island also disappeared as a result of human activities.
Emu was once common on the east coast of Australia, but now they are rarely seen there. The development of agriculture and the supply of water for livestock in the interior of the continent increased the range of emus in dry regions. Giant birds live in a variety of habitats throughout Australia, both inland and off the coast. They are most common in areas of savannah and sclerophyllous forest and least common in densely populated areas and arid areas with annual precipitation not exceeding 600 mm.
Emus prefer to travel in pairs, and although they can form large flocks, this is an atypical behavior that arises from the general need to move to a new food source. The Australian ostrich can travel long distances to reach abundant feeding areas. In the western part of the continent, the movements of the emu follow a clear seasonal pattern – north in summer, south in winter. On the east coast, their wanderings seem more chaotic and do not follow a set pattern.
What does the emu eat?
Emus are eaten by various native and introduced plant species. The plant-based diet is seasonal, but they also eat insects and other arthropods. This provides most of their protein requirement. In Western Australia, traveling emus eat acacia aneura seeds until the rains begin, after which they move on to fresh grass shoots.
In winter, birds feed on cassia pods, and in spring, grasshoppers and the fruit of the woody bush Santalum acuminatum. Emus are known to feed on wheat and any fruit or other crop they have access to. They climb over high fences if necessary. Emus serve as an important carrier of large viable seeds, which contributes to the biodiversity of flowers.
One undesirable effect of seed transfer occurred in Queensland in the early twentieth century when emus moved prickly pear cactus seeds to different locations, and this led to a series of campaigns to hunt emu and prevent the spread of invasive cactus seeds. The cacti were eventually controlled by an introduced moth (Cactoblastis cactorum), whose larvae feed on the plant. This became one of the earliest examples of biological control.
Small stones are swallowed by the emus to aid in the grinding and assimilation of plant material. Individual stones can weigh up to 45g, and birds can have as many as 745g of stones in their stomachs at one time. Australian ostriches also eat charcoal, although the reason for this is unclear.
The diet of the emu is:
- various herbs;
- moth larvae;
Domesticated emus swallowed pieces of glass, marble, car keys, jewelry, nuts and bolts. Birds drink infrequently, but at the first opportunity they use a large amount of liquid. First, they survey the pool and surrounding areas in groups, and then kneel at the edge to drink.
Ostriches prefer to be on solid ground while drinking rather than rocks or mud, but if they feel threatened, they remain standing. If the birds are not disturbed, ostriches can drink continuously for ten minutes. Due to the lack of water sources, they are sometimes forced to go without water for several days. In the wild, emus often share water sources with kangaroos and other animals.
Character and lifestyle features
Emus spend their day foraging, cleaning their plumage with their beaks, bathing in dust, and resting. They are generally sociable except during the breeding season. These birds can swim when needed, although they only do so if their area is flooded or a river needs to be crossed. Emus sleep intermittently, waking up several times a night. When falling asleep, they first squat down on their legs and go into a sleepy state gradually.
If there are no threats, they fall into a deep sleep after about twenty minutes. During this phase, the body descends until it touches the ground with the legs folded down. Emus wake up from deep sleep every ninety minutes to eat or defecate. This period of wakefulness lasts 10-20 minutes, after which they fall asleep again. Sleep lasts about seven hours.
Emu makes various booming and wheezing sounds. A powerful hum can be heard at a distance of 2 km, while a low, more resonant signal emitted during the breeding season can attract partners. On very hot days, emus breathe to maintain their body temperature, their lungs working as coolants. Emus have a relatively low metabolic rate compared to other types of birds. At -5°C, a seated emu’s metabolic rate is about 60% that of a standing emu, in part because the lack of feathers under the stomach results in a higher rate of heat loss.
Social structure and reproduction
Emus form breeding pairs from December to January and can stay together for about five months. The mating process takes place between April and June. A more specific time is determined by the climate, as the birds nest during the coolest part of the year. Males build a crude nest in a semi-enclosed hollow on the ground using bark, grass, sticks and leaves. The nest is placed where the emu has control of its environment and can quickly detect approaching predators.
Interesting fact: During courtship, females walk around the male, pulling their necks back, tearing off feathers and emitting low monosyllabic calls that are similar to drum beats. Females are more aggressive than males and often fight for their chosen mates.
The female lays one clutch of five to fifteen very large, thick-shelled green eggs. The shell has a thickness of about 1 mm. Eggs weigh between 450 and 650 g. The surface of the egg is granular and pale green. During the incubation period, the egg becomes almost black. The male may begin incubating the eggs before clutch is complete. From that time on, he does not eat, drink, or defecate, but gets up only to turn the eggs.
During the eight week incubation period, he loses a third of his weight and survives on stored fat and morning dew , which he takes out of the nest. As soon as the male sits on the eggs, the female can mate with other males and create a new clutch. only some females stay and protect the nest until the chicks begin to hatch.
Incubation takes 56 days and the male stops incubating the eggs shortly before they hatch. Newborn chicks are active and may leave the nest within a few days of hatching. At first they are about 12 cm tall and weigh 0.5 kg. They have characteristic brown and cream streaks for camouflage that disappear after three months. The male guards the growing chicks for up to seven months, teaching them how to find food.
Natural enemies of emus
There are few natural predators of emus in their habitat due to the bird’s size and speed of movement. Early in its history, the species may have encountered numerous now-extinct terrestrial predators, including the giant megalania lizard, the thylacine marsupial, and possibly other carnivorous marsupials. This explains the emu’s well-developed ability to defend itself against land-based predators.
The main predator today is the dingo, a semi-domesticated wolf, the only predator in Australia before the arrival of Europeans. The dingo aims to kill the emu by trying to hit its head. And the emu, in turn, tries to push the dingo away by jumping into the air and kicking the leg.
The jumps of the bird are so high that it is difficult for the dingo to compete with it in order to threaten the neck or head. Therefore, a properly timed jump, coinciding with a lunge of a dingo, can protect the animal’s head and neck from danger. However, dingo attacks do not have a strong impact on the number of birds in the fauna of Australia.
The wedge-tailed eagle is the only avian predator to attack the adult emu, although it is more likely to select small or juveniles. The eagles attack the emu by descending quickly and at high speed and aiming at the head and neck. In this case, the jumping technique used against the dingo is useless. Birds of prey try to target the emu in open spaces where the ostrich cannot hide. In such a situation, the emu uses a chaotic movement technique and often changes direction in an attempt to evade the attacker. There are a number of predators that feed on emu eggs and eat small chicks.
- large lizards;
- introduced red foxes;
- wild dogs;
- wild boars occasionally feed on eggs and chicks;
The main threats are loss and fragmentation of habitat, collision with vehicles and deliberate hunting. In addition, fences hinder the movement and migration of emus.
Population and species status
John Gould’s Birds of Australia, published in 1865, deplored the loss of the emu in Tasmania, where the bird had become rare and then completely extinct. The scientist noted that emus are no longer common in the vicinity of Sydney, and suggested giving the species a protected status. In the 1930s, emu kills in Western Australia peaked at 57,000. The culling has been linked to damage to crops in Queensland during this period.
In the 1960s, emu killing bounties were still paid out in Western Australia, but the wild emu has since been given official protection under c The Biodiversity Conservation and Conservation Act 1999. Although the number of emus on the Australian mainland is believed to be even higher now than before European resettlement, some local groups are still endangered.
Threats Emu encounters include:
- clearing and fragmenting areas with suitable habitat;
- deliberate destruction of livestock;
- traffic collisions;
- predation of eggs and young.
The emu was estimated in 2012 to have a population of 640,000 to 725,000 individuals. The International Union for Conservation of Nature notes the emerging trend towards stabilization of the number of livestock and assesses their conservation status as having the least concern.