Emu

## Description

The emu (Dromaius novaehollandiae) is the second-largest living bird by height, after its ratite relative, the ostrich. It is endemic to Australia where it is the largest native bird and the only extant member of the genus Dromaius. Emus can travel great distances, and when necessary can sprint at 48 km/h (30 mph); they forage for a variety of plants and insects, but have been known to go for weeks without eating. They drink infrequently but take in copious amounts of water when the opportunity arises.

## Appearance

Adult emus have a covering of shaggy gray-brown feathers, apart from the heads and necks, which are mostly naked and bluish-black. The plumage varies in color due to environmental factors, giving the bird a natural camouflage. Feathers of emus in more arid areas with red soils have a rufous tint while birds residing in damp conditions are generally darker in hue. The juvenile plumage develops at about three months and is blackish finely barred with brown, with the head and neck being especially dark. The facial feathers gradually thin to expose the bluish skin. The wings of emus are greatly reduced in size, but they have long and powerful legs. There are three forward-facing toes on each foot, but no hind toe. When walking, the emu takes strides of about 100 cm (3.3 ft), but at full gallop, a stride can be as long as 275 cm (9 ft). It has sharp claws on its toes which are its major defensive attribute, and are used in combat to inflict wounds on opponents by kicking. Emus have good eyesight and hearing, which allows them to detect threats at some distance. The eyes of an emu are protected by translucent, secondary eyelids that move horizontally from the inside edge of the eye to the outside edge. They function as visors to protect the eyes from the dust that is prevalent in windy arid regions. Emus also have a tracheal pouch, which becomes more prominent during the mating season. At more than 30 cm (12 in) in length, it is quite spacious; it has a thin wall, and an opening 8 cm (3 in) long.

## Distribution

Australia is the only place emus are found and they inhabit almost the entire continent. There are fewer of them toward the center of the country and along the eastern coast. Historically they also lived on King and Kangaroo Islands, and on Tasmania, but on all three islands, the species is now extinct. Emus inhabit a range of habitats including grassland, dry forest, wooded savannah, and semi-desert, but not the tropical forests in northeastern Australia.

## Behavior

An emu is generally a solitary bird but will exhibit social behaviors when it is advantageous, such as sharing a nest and searching for food. Large groups will migrate together to the next source of food. During periods of incubation, emus are not nomadic. The home range of an individual measures 5 to 10 square km but is a dynamic area, as emus are always moving in search of food and water. This species is strictly diurnal. They wake very often during periods of sleep, due to threats from predators and the need to drink water. They exhibit playful curiosity with animals of their own and other species, particularly noted in captive environments. An example is biting or pecking another animal than running away, simply to get a response. They will swim when water is available, and are adept at this. These birds are able to communicate by means of an inflatable neck sack, creating sounds that carry 2 km. Their name is from their signature call, which sounds like "e-moo".

## Diet

Emus are omnivorous and eat seeds, flowers, fruits, and tender roots. During the summer they eat many insects, especially caterpillars, beetles, and grasshoppers, and also small vertebrates.

## Reproduction

Emus are polyandrous, which means that one female has multiple partners. A pair remains together for around five months, engaging in courtship, nest building, and the laying of eggs. The female is dominant during pair formation but when incubation begins, she becomes aggressive to all other emus, her mate included. She wanders off and leaves all the incubation to him. The mating season is from December to January, starting with the pair doing a courtship dance. Then the male builds a nest of twigs, leaves, and grass on the ground, in the shelter of vegetation. From April to May, 5 to 15 dark green eggs are laid. The male incubates them for about 8 weeks. Chicks are precocial and can walk within 24 hours. They are protected by their cryptic stripped down. They are able to leave the nest 2 to 7 days after hatching, running, and swimming very soon after that. The male looks after the young for 5 months, sometimes for as long as 18 months. They become mature by 2-3 years old.

## Population

### Population threats

Today the emu remains abundant and widespread. Following the arrival of settlers from Europe, emus were widely hunted for oil and meat, and their eggs were collected for food. As a result, they became extinct on several islands, including Tasmania.

### Population number

According to the IUCN Red List, the total emu population size is estimated at 630,000 to 725,000 mature individuals. Currently, this species is classified as Least Concern (LC) and its numbers today remain stable.

### Ecological niche

An emu disperses over a wide area the seeds from many low-growing plants, due to their nomadic migratory habits. Some seeds feature a specialized coating that, once digested, increases the chance they will sprout.

## Fun Facts

The word 'emu' does not come from the Aborigine language. It may come from an Arabic word meaning “large bird” and was later applied by early Portuguese explorers to the cassowaries of eastern Indonesia. It was then used for the emu by the early European explorers in Australia.

The male emu neither eats nor drinks during incubation. For this reason, beforehand, he builds up his fat reserves. During incubation, he goes into a state of torpor so the amount of water loss will be reduced during this period. But he turns the eggs a few times each day, stays on the nest or close to it, and preens.

An emu has two pairs of eyelids: one is for blinking and the other is to keep dust out.

A male makes a sound like a pig’s grunt and a female makes loud booming sounds.

Emus require water daily. When the weather is cold, they recycle air in their nasal passages to create moisture they can use.

Emus swallow pebbles and small rocks to assist in the grinding of food and to accelerate digestion.