Emu: Dromaiidae

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EMU: Dromaiidae

PHYSICAL CHARACTERISTICS

The emu is the largest bird native to Australia and the second largest bird in the world. Emus are 60 to 75 inches (150 to 190 centimeters) in height and weigh 51 to 120 pounds (23 to 55 kilograms). They have long, strong legs and can run up to 30 miles per hour (48 kilometers per hour). They have long necks and short wings. The adults have brown feathers while the chicks are striped with black, brown, and cream-colored feathers. They have heads with blue skin and stiff black hair. Females are slightly larger than males.

Emus belong to a group of birds called ratites (RAT-ites), which are flightless birds that have a flat breastbone rather than a keeled or curved breastbone like birds of flight. They have a simplified wing bone structure, strong legs, and no feather vanes, making it unnecessary for them to oil their feathers. Consequently, they have no preen gland that contains preening oil, unlike most birds.

Emus have long, loose double feathers in which the aftershaft, or the secondary feather that branches from the base of the main feather, is as long as the main feathers.

GEOGRAPHIC RANGE

Emus are found throughout Australia. They are most common in southern Australia although they can be found as far north as the city of Darwin.

HABITAT

Emus live in eucalyptus forests, woodlands, shrublands, desert, sandy plains, grasslands, and high alpine plains.

DIET

Emus are omnivores, meaning they eat both plants and flesh. They prefer plant parts that are rich in nutrients they need, such as seeds, fruits, flowers, and young shoots. They also eat insects, such as grasshoppers, beetles, and caterpillars. More rarely, they will eat lizards, snakes, small rodents, and small marsupials (animals that have a pouch). They usually drink water every day and get some of the liquid they need from plants. They also swallow pebbles to aid with digestion.

BEHAVIOR AND REPRODUCTION

Emus are diurnal, meaning they are most active during the day. They live in pairs and are nomadic, following the rain to feed. They can walk considerable distances at a steady pace of 4.3 miles (7 kilometers) per hour covering 9 feet (270 centimeters) in a single stride. Emus are also strong swimmers.

Emus have adapted well to their Australian environment, where it is often arid and food is not always available in the same place throughout the year. To find food once an existing supply is exhausted, emus sometimes travel hundreds of miles (kilometers) to find a new food source. They have also adapted to the often-harsh Australian environment with their food storage ability. When food is plentiful, emus store large amounts of fat that they live off of while searching for new food supplies. Sometimes, adult emus will lose more than 50% of their weight while in between food supplies, dropping from 100 pounds (45 kilograms) to 44 pounds (20 kilograms.)

Emus are solitary creatures and although they often travel in large flocks, this is not social behavior, rather simply going where there is food. In Western Australia, emu migration runs north in summer and south in winter. In eastern and southern Australia, their wanderings are random. On extremely hot days, emus pant, meaning they open their mouths and breathe very rapidly, much like dogs, using their lungs as evaporative coolers.

Emus have an uncanny and ill-understood way of detecting rain from several hundred miles (kilometers) away. Researchers believe this is a combination of sighting distant rain cloud formations, smelling rain, and hearing the far-off sound of thunder from distances the human ear cannot.

Male and female emus pair up in December and January, establishing a territory of about 12 square miles (30 square kilometers) where they mate. The male builds a nest by placing bark, grass, twigs, and leaves in a shallow depression in the ground. In April, May, and June, the female lays large, thick-shelled dark green eggs, with one nest containing the eggs of several females. When a nest has about eight to ten eggs, the male incubates them, meaning he sits on the eggs to keep them warm until they hatch. Nests can contain fifteen to twenty eggs on occasion.

From the time the male starts incubating the eggs, he does not eat, drink, or pass bodily wastes. The male survives only on accumulated body fat. He sits on the nest twenty-four hours a day, standing about ten times a day to turn the eggs. The eggs hatch in about fifty-six to sixty days. The chicks remain with the male for five to seven months. The young reach sexual maturity at two to three years of age. The average lifespan of emus in the wild is five to ten years.

EMUS AND PEOPLE

Emus have been roaming Australia for eighty million years, when dinosaurs still walked the Earth. But even though they survived the extinction event that killed the dinosaurs, they came close to being wiped out by humans. In 1901, farmers in Western Australia built a 682-mile (1,100-kilometer) fence to keep emus away from grain crops. But the fence disrupted emu migration and as many as 50,000 birds died each year from starvation.

In 1932, the Australian government literally declared war on the big bird. Army troops with truck-mounted machine guns and hand grenades were used to hunt down and kill emus. The war was short-lived after the army learned the fast-running birds could easily outmaneuver them. Still, it is estimated that hundreds were killed. Emus are now protected by law and the total population in the wild is estimated at 500,000 to one million.

Emus are raised commercially in the United States, Australia, Europe, and South Africa for their meat, skin, eggs, and feathers. Farmers in Australia often consider them agricultural pests. Emu oil is also being studied in the United States for its possible medical applications. It is used as an antiseptic, moisturizer, and anti-inflammatory agent. It is also found in eye creams, hair care products, and other cosmetics. Research indicates that emu oil promotes wound healing and may be effective in treating arthritis. The U.S. Food and Drug Administration has not approved its use for medical conditions.

CONSERVATION STATUS

The emu is not listed as threatened by the IUCN. Two species, the Kangaroo Island emu and the King Island emu, as well as one subspecies, the Tasmanian emu, became extinct in the 1800s due to hunting by humans.

FOR MORE INFORMATION

Books:

Davies, S. J. J. F., et al. Bird Families of the World. Vol. 8, Ratites and Tinamous: Tinamidae, Rheidae, Dromaiidae, Casuariidae, Apterygidae, Struthionidae. Oxford, U.K.: Oxford University Press, 2002.

Elwood, Ann, and John B. Wexo. Ostriches, Emus, Rheas, Kiwis, and Cassowaries (Zoo Books). Mankato, MN: Creative Education, 2000.

Fowler, Allan. These Birds Can't Fly. New York: Bt Bound, 2001.

Harris, Timothy. Ostriches, Rheas, Cassowaries, Emus, and Kiwis. New York: Beech Publishing House, 1997.

Simpson, Ken, and Nicolas Day. Birds of Australia. Princeton, NJ: Princeton University Press, 2000.