Ratites are a group of large, flightless birds that includes ostriches, emus, rheas, cassowaries, and kiwis. They are distinguished by their flat breastbones and lack of a keel, which prevents them from being able to fly. Despite their inability to fly, ratites are very quick on their feet and can run at high speeds using their powerful legs. There are only 5 living species of ratites remaining today.
Ostrich
The ostrich is the largest and most well-known ratite. Native to Africa, ostriches can grow up to 9 feet tall and weigh over 300 pounds. Ostriches are distinctive for their long, bare necks, large eyes, and long legs. They have powerful legs that allow them to run at speeds up to 43 miles per hour, making them the fastest land bird in the world. Ostriches are covered in shaggy, two-toned feathers – their bodies are black with white wings and tail. They have only two toes on each foot. Ostriches are omnivorous and feed on plants, seeds, fruits, and some small animals.
Ostriches live in nomadic groups called herds that are led by a dominant breeding pair. Ostrich eggs are the largest of all eggs, averaging 6 inches long and 5 inches wide. The eggs can weigh up to 3 pounds. The female ostrich will lay her eggs in a communal nest that is watched over by one or more dominant females. Male ostriches may incubate the eggs at night. Ostrich chicks are precocial, meaning they hatch already covered in down feathers and are able to walk and feed themselves soon after hatching.
Ostriches are found in the wild in Africa, mostly south of the Sahara Desert. Their native habitat includes open savanna plains and the semi-arid Sahel region. However, ostriches have been introduced to some other parts of the world including Australia and areas of North America. Ostriches are raised commercially in many countries for their meat, leather, and decorative feathers. Some ostrich farms also allow tourists to ride ostriches.
Emu
Emus are the second largest ratite and are native to Australia. They can reach up to 6 feet in height and weigh over 100 pounds. Emus have long necks and legs, but their bodies are covered in shaggy, brown feathers. Their heads are featherless with bluish skin. Emus have three toes on each large, powerful foot. They can run at speeds up to 30 miles per hour.
Emus feed on fruits, seeds, insects, and flowers. They live in nomadic flocks of up to 50 birds. Male emus build nests on the ground where the female lays 5-15 green eggs. The male incubates the eggs and raises the chicks alone without any help from the female. Emu chicks grow quickly, reaching full size within 6 months. Emus are found in the wild across Australia in a variety of habitats including forests, savanna, and deserts.
Like ostriches, emus are sometimes raised on farms for their meat, oil, and leather. Emu oil is valued for its medicinal properties and as a natural moisturizer. The emu is an important cultural symbol to Aboriginal Australians. It appears in Aboriginal mythology and its feathers are used in rituals and ceremonies.
Greater Rhea
The greater rhea is a large, flightless bird native to South America. It stands up to 5 feet tall and can weigh over 60 pounds. The greater rhea has a small head with a pointed beak and long legs with three toes on each foot. Its body feathers are gray-brown while its wing feathers are black. Greater rheas are found in grasslands, savannas, and scrublands in central and eastern South America. They form small flocks that feed on plants and seeds.
Greater rheas breed seasonally – males build nests on the ground where multiple females will lay eggs. The male incubates and guards the eggs until they hatch. Rhea chicks can run shortly after hatching but are cared for by their fathers for the first six months of life. Greater rheas are still hunted for their meat and eggs across their native range. However, they remain widespread and are classified as a species of Least Concern by the IUCN Red List.
Common Rhea
Very similar to the greater rhea, the common rhea is found further south in open habitats across Argentina, Brazil, Paraguay, and Bolivia. The common rhea stands about 4 feet tall and weighs 40-55 pounds. It has gray-brown body plumage and lighter wing feathers. During the breeding season, males develop light blue skin on their heads and necks. Common rheas form flocks of 10-100 individuals.
Like other ratites, common rheas cannot fly but are fast runners with a top speed around 40 miles per hour. They build nests on the ground where females lay 10-60 eggs that are incubated solely by the male. Common rhea chicks reach full size in about 14 months. Their meat and hides are still hunted by people across their range. However, they remain widespread and are evaluated as Least Concern on the IUCN Red List.
Cassowary
Cassowaries are the only ratites native to the rainforests of Northern Australia and New Guinea. There are three species of cassowary – the southern, dwarf, and northern cassowary. Cassowaries are shorter than emus but heavier, weighing 130-200 pounds. They have black, hair-like feathers on their bodies, small wings with browner feathers, bright blue necks, and horn-like casques on their heads. Cassowaries are frugivores that mainly eat fallen fruits.
Cassowaries lead solitary lives but come together to breed and raise chicks. The male incubates the eggs and raises the chicks alone. If threatened, cassowaries can deliver dangerous kicks with their large feet that have dagger-like claws. Two of the three cassowary species are classified as Vulnerable to extinction by the IUCN Red List due to habitat loss, car collisions, and hunting for their meat.
Kiwi
Kiwis are the smallest ratites and the only ones native to New Zealand. There are five species of kiwi ranging in size from 15-25 inches in height and 2-7 pounds in weight. Kiwis are nocturnal and have small eyes, whiskers, and a long beak with nostrils at the tip that they use to probe the ground for food. Rather than wings, kiwis have small vestigial wings with claws that are hidden beneath their shaggy, hair-like feathers.
Kiwis live in monogamous pairs that share parenting duties. Females lay up to 3 eggs in burrows each season that are incubated by the male for up to 3 months – the longest incubation period of any bird. Kiwi chicks hatch fully feathered and are able to feed themselves, but they are still vulnerable. All kiwi species are threatened by habitat loss and predation by invasive mammals. Their populations continue to decline, with some species now numbering only in the hundreds.
Comparison of Ratites
Species | Location | Height | Weight | Diet | IUCN Status |
---|---|---|---|---|---|
Ostrich | Africa | 6-9 ft | 220-320 lbs | Omnivore | Not Threatened |
Emu | Australia | 5-6 ft | 55-110 lbs | Omnivore | Least Concern |
Greater Rhea | South America | 4-5 ft | 45-65 lbs | Herbivore | Least Concern |
Common Rhea | South America | 3.5-4 ft | 40-55 lbs | Herbivore | Least Concern |
Cassowary | Australia, New Guinea | 5-6 ft | 60-130 lbs | Frugivore | Vulnerable |
Kiwi | New Zealand | 15-20 in | 2-7 lbs | Insectivore | Vulnerable |
Conclusion
In summary, there are 5 living species of ratites remaining in the world today – the ostrich, emu, two types of rheas, cassowaries, and kiwis. Ratites are flightless birds characterized by their flat breastbones. While they lost their ability to fly, ratites compensated with adaptations like large size, powerful legs for running, and sharp claws for defense. Most ratites are omnivorous or herbivorous, feeding on fruits, seeds, plants, and some small animals.
Ostriches are the largest and fastest running ratites, native to Africa. Emus fill an ecological niche similar to ostriches, but are native to Australia instead. Rheas resemble small ostriches and are found in South America. Cassowaries are frugivores that live in the rainforests of Australia and New Guinea. Kiwis are the smallest, most specialized ratites – they are nocturnal insectivores adapted for life in New Zealand. Though some ratite species remain abundant, others are Vulnerable to extinction from threats like habitat loss and predation. Conservation efforts are needed to ensure the survival of all five remaining species of these fascinating flightless birds into the future.