Emu
Emu Facts
| Size | 4.9-6.2 feet (150-190 cm) |
| Speed | Up to 31 mph (50 km/h) |
| Weight | 66-120 pounds (30-55 kg) |
| Lifespan | 10-20 years |
| Food | Seeds, fruits, grasses, insects |
| Predators | Dingoes, eagles, foxes, wild dogs |
| Distribution | Australia |
| Habitat | Grasslands, eucalyptus forests, savannas |
| Order | Ratites |
| Family | Casuariidae |
| Scientific name | Dromaius novaehollandiae |
| Characteristics | Second largest bird, lays green eggs, has soft feathers |
Main Characteristics
Emus are large running birds with long legs and soft, lengthy feathers. They are the second largest birds in the world after ostriches – and the largest in Australia. While they cannot fly, they can run swiftly. Another unique aspect of emus is that they lay enormous dark green eggs! Additionally, unlike most other birds, it is the male emu that takes care of incubating the eggs and raising the chicks.
Ratites
Emus, along with ostriches, rheas, cassowaries, and kiwis, are classified as ratites birds. They are capable of running swiftly and efficiently. However, none of them can fly, as they are either too large and heavy or possess underdeveloped wings (like the kiwi).
Name
The term "Emu" likely originates from the Portuguese word ema or the Arabic term for "large bird." Portuguese explorers initially used this name for large running birds such as the South American rhea or the African ostrich, before it became associated specifically with the Australian running bird.
Distribution and Habitat
Emus are native to Australia. They favor open grasslands, savannas, light eucalyptus forests, and scrublands. They tend to avoid dense rainforests and extreme deserts.
Lifestyle
Emus are diurnal birds. They spend a significant amount of time searching for food and water, which means they are almost always on the move, covering distances of 15-25 km each day. They are most active in the mornings and during twilight. Although they are generally solitary, they do form small groups of about 20 individuals when they migrate.
Anatomy and Appearance
Size and Weight
Emus are the second largest birds in the world. They can reach a body height of 4.9-6.2 feet (150-190 cm) and a shoulder height of 3.2-4.2 feet (100-130 cm) (excluding the neck). Surprisingly, despite their size, they weigh only 66-120 pounds (30-55 kg).
Color
Emus have dark brown feathers that become lighter as they age. The skin on their neck and head is blue.
Feathers or Hair?
The plumage of emus resembles shaggy fur. In most birds, a single feather grows from one follicle, similar to how only one hair grows from a hair follicle in humans. However, this is not the case for emus. From one "hair" follicle, two (!) feather shafts grow. This is known as a double feather. Unlike the feathers of other birds, these lack hooks, making them very soft and droopy, giving the appearance of many fine hairs.
Legs and Calf Muscles
Emus have extremely strong hind legs with three toes. They are the only birds in the world that possess calf muscles similar to those of mammals. These muscles act like springs when they run, allowing for strides of up to 8.8 feet (2.7 meters).
Eyes
Emus have a transparent skin covering their eyes. This is known as the nictitating membrane, which functions like a third eyelid. It helps keep their eyes moist and protects them from dust and dirt in dry areas.
Diet
Emus are omnivores. They mainly enjoy plant-based foods such as leaves, grass, seeds, fruits, and berries. In addition, they consume beetles, caterpillars, grasshoppers, and other invertebrates. Lacking teeth to cut or chew their food, they simply swallow it whole. To aid in breaking down their meals, they also ingest small stones, which help crush the food in their stomachs.
Behavior
Are Emus Dangerous?
Emus are peaceful birds. They only become aggressive when threatened or to defend their nests.
How Do Emus Defend Themselves?
When faced with danger, Emus flee in a zigzag pattern! But what happens if they can't escape in time? They can become quite unpleasant. If a predator gets too close, they deliver a powerful kick with their strong legs. This can seriously injure the attacker, as they have three long, sharp toes on their feet!
Adapting to Heat and Cold
- In Heat: The feathers help the Emu maintain its body temperature. When it gets warm, it raises its wings and waves them. To cool down, it sometimes pants like a dog!
- In Cold: When it's cold, the Emu puffs up to trap warm air between its feathers.
- Bathing: Emus enjoy bathing in shallow waters. After a bath, they shake themselves off like a wet dog to dry their feathers.
Wandering: Following the Rain
Emus sometimes travel long distances in search of food and water. They usually head in the direction where they suspect rain. In winter, they primarily move south, and in summer, they head north.
Senses and Abilities
Speed
The emu may not be as fast as the ostrich, but it can reach an impressive speed of up to 31 mph (50 km/h). With each stride, it can cover a distance of 8.8 feet (2.7 meters).
Unusual Sounds
Emus produce very unique sounds. They hiss, grunt, bark, and growl. One notable sound is called "booming". These are deep drum and timpani-like noises created by the females using an inflatable air sac in their throat. The "booming" can even be heard from over one mile (1.5 km) away.
Lifespan
In the wild, emus typically live for 10-20 years. The oldest emu on record lived to be 38 years old.
Enemies and Threats
Natural Enemies
Adult emus have few enemies in Australia due to their size. The most dangerous natural predator is the dingo, which often hunts in packs and tries to grab the emu by the neck. For chicks and eggs, threats include wedgetail eagles, large monitor lizards, and quolls
Human Impact
The emu is not considered an endangered species. However, it faces several threats: agriculture (mainly for livestock), road construction and traffic, dingo fences, and climate change. Additionally, introduced predators like foxes, as well as feral dogs and cats, hunt the eggs and chicks.
Importance for the Ecosystem
Emus consume seeds and nuts. However, these are not digested and pass through the stomach and intestines intact. As these animals wander several miles each day, they assist in sowing new plants. Additionally, they help maintain the balance of insect populations.
Reproduction
Green Giant Eggs
Emu eggs are dark green to nearly black and feature a rough shell. They measure about 13-15 cm in length, have a diameter of 9 cm, and weigh 500-700 g – equivalent to the weight of around 10-12 chicken eggs.
The Hens (!) Court the Males
In emu behavior, it's the hens that court the males, not the other way around. The female circles the male from a distance of 10-50 m. If he shows interest, he approaches, and they mate. Over a span of two to three days, they lay a total of 5-15 eggs. After this, the hen moves on to mate and lay more eggs. So, what happens next? Are the eggs left unattended?
The Father Incubates Alone
Fortunately, male emus are very caring fathers. Once the eggs are in the nest, they stop eating and drinking to guard and incubate the nest around the clock. For eight weeks! By the time the chicks hatch, the father has usually lost about a third of his body weight.
And He Raises the Chicks
Even after the chicks hatch, the male diligently cares for them. He protects them from all dangers and teaches them what they can eat. After six months, the chicks are fully grown. However, they remain with their father for an additional 12 months.
First Bird with Twin Chicks
Twin births are known not only in humans but also in mammals. However, they are quite rare in the bird world. The emu is the first bird documented to have produced completely identical, monozygotic twin chicks.
Fun Facts
Emu in the Sky
Among the Aborigines, the emu is represented not by stars, but by dark dust clouds in the Milky Way.
The Emu War of 1932
In 1932, emus devastated wheat fields. The Australian government enlisted soldiers to shoot them. However, due to the emus' incredible speed and their ability to change direction suddenly, the "war" had to be called off unsuccessfully.
A Popular Symbol
In Australia, over 600 locations are named after the emu: mountains, lakes, rivers, towns, beer brands, magazines, and much more. Alongside the kangaroo, the emu is even featured on the Australian coat of arms. Both animals symbolize progress, as they find it difficult to move backward.
The Emu Is Related to:
- Cassowary
Animals in the Same Habitat:
- Bearded Dragon
- Brown Snake
- Cockatoo
- Dingo
- Echidna
- Koala
- Red Kangaroo
- Wombat
Sources:
- Genetically identical avian twins (https://www.cambridge.org)
- Bird Families of the World: Ratites and Tinamous: Tinamidae, Rheidae, Dromaiidae, Casuariidae, Apterygidae, Struthionidae (https://www.researchgate.net)
- Pelvic limb musculature in the emu Dromaius novaehollandiae (Aves: Struthioniformes: Dromaiidae): adaptations to high-speed running (https://pubmed.ncbi.nlm.nih.gov)
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