Ostrich

## Description

The common ostrich (Struthio camelus ), or simply ostrich, is a species of flightless bird native to certain large areas of Africa and is the largest living bird species. It is one of two extant species of ostriches, the only living members of the genus Struthio in the ratite order of birds. The other is the Somali ostrich (Struthio molybdophanes ), which was recognized as a distinct species by BirdLife International in 2014 having been previously considered a distinctive subspecies of ostrich.

The common ostrich belongs to the order Struthioniformes. Struthioniformes previously contained all the ratites, such as the kiwis, emus, rheas, and cassowaries. However, recent genetic analysis has found that the group is not monophyletic, as it is paraphyletic with respect to the tinamous, so the ostriches are now classified as the only members of the order. Phylogenetic studies have shown that it is the sister group to all other members of Palaeognathae and thus the flighted tinamous are the sister group to the extinct moa. It is distinctive in its appearance, with a long neck and legs, and can run for a long time at a speed of 55 km/h (34 mph) with short bursts up to about 70 km/h (40 mph), the fastest land speed of any bird. The common ostrich is the largest living species of bird and largest living dinosaur. It lays the largest eggs of any living bird (the extinct elephant birds of Madagascar and the giant moa of New Zealand laid larger eggs).

The common ostrich's diet consists mainly of plant matter, though it also eats invertebrates and small reptiles. It lives in nomadic groups of 5 to 50 birds. When threatened, the ostrich will either hide itself by lying flat against the ground or run away. If cornered, it can attack with a kick of its powerful legs. Mating patterns differ by geographical region, but territorial males fight for a harem of two to seven females.

The common ostrich is farmed around the world, particularly for its feathers, which are decorative and are also used as feather dusters. Its skin is used for leather products and its meat is marketed commercially, with its leanness a common marketing point.

## Appearance

These enormous birds, usually taller than a human, live in the deserts and savannas of Africa. They are the tallest, largest, and heaviest birds alive, and one of the most unique. Their relatively small head features the largest eyes (5 cm in diameter) of any land animal, protected by their long black lashes. A male has bold black-and-white markings that are used to attract females, while females are light brown. Ostriches have rather prehistoric-looking feet, and are the only birds with only two toes on each foot. The inner one is thick and strong, and is adapted for running. It has a formidable claw, 10 cm long, which may be used in defense.

## Distribution

Ostriches live in the wild in western and eastern Africa, as well as South Africa. Once they roamed all over Africa, Asia, and the Arabian Peninsula. Ostriches farmed in Australia, New Mexico, and Israel have established feral populations. These birds inhabit open land and are native to the savannas and Sahel of Africa, both north and south of the equatorial forest zone. In southwest Africa, they inhabit the semi-desert or true desert. They can also be found in dry grasslands, scrubby areas, and pasturelands.

## Behavior

Ostriches live in flocks numbering 5 to 50, and are normally found alongside grazing animals such as antelope and zebras. During the breeding season, of about 5 months, flocks will occupy territories extending 2-15 sq km. Outside the breeding season, smaller, looser flocks of 2-5 members form. Ostriches have a lifestyle which is nomadic and mostly diurnal, being active early in the day as well as late. Males are territorial, defending their territory aggressively. These birds like water and frequently take baths, if given the opportunity, and are good swimmers. Sometimes, to escape detection, they lie down with their necks outstretched, which probably was the origin of the myth that an ostrich buries its head in the sand. They use posture to threaten a rival or predator, fluffing up the feathers of their wings and hissing loudly. These birds are fast runners and usually will comfortably outrun their predators. Ostriches are very vocal, and their sounds include whistling, booming, snorting and hissing.

## Diet

Ostriches are mainly herbivores (granivores), they eat buds, leaves, seeds and flowers, and sometimes lizards, grasshoppers and animal remains that carnivorous predators have left.

## Reproduction

Ostriches are polygynous, each male having three to five hens, with a “major” hen and several “minor” hens. Dominant males defend their territory and mate with their major hen and other hens within the area. The major hen is given more careful consideration, getting first choice of nesting ground. She lays her eggs first, then allows the others in the flock to produce theirs. The major hen will know which are her eggs and protects her clutch by pushing away other hens’ eggs. The mating season starts in March or April, running until September. The male will scrape out a nest, which is just a depression in the ground, then attracts the hens by dancing, fluffing up his feathers and flapping his wings, as well as swinging his head while going down on his knees. Females lay 2 to 11 creamy eggs in the communal nest. Only dominant male and major female guard the nest. The eggs are incubated for about 6 weeks. The female is on the nest during daylight hours, and the male at night. Within the first three days the chicks leave the nest. They fledge when they are 4 to 5 months old, and by about 18 months they are fully grown, reaching maturity at 2 to 4 years.

## Population

### Population threats

Although not considered globally threatened and still relatively abundant, in recent times, ostrich numbers have decreased, as has their range. Their feathers and eggs have been used by humans for a long time, almost causing their extermination in northern and southern Africa. Overgrazing has caused habitat destruction and greatly reduced their range, this currently being the main threat.

### Population number

According to the Animal-Corner resource, the total population size of the ostrich is around 2 million individuals worldwide. Currently this species is classified as Least Concern (LC) on the IUCN Red List, but its numbers today are decreasing.

## Fun Facts for Kids

The ostrich is unique amongst birds in having two toes on each of its feet. All other birds possess three or four toes.

"Strothio camelus", the ostrich’s scientific name, means camel-like.

The feathers of the ostrich are unusual because they don’t have the usual tiny hooks that keep the feather together, leaving the barbs or ‘branches’ loose, and giving the feathers a very soft, smooth feel.

Males change color during the breeding season, their skin turning bright red, signaling to the hens that they are ready to mate.

One ostrich egg weighs as much as 24 or so chicken eggs.

Ostriches peck curiously at small, shiny objects, being attracted to them.

In Nairobi National Park, one communal ostrich nest had 78 eggs from different females.

Lacking teeth, ostriches ingest pebbles in order to grind their food, with an adult ostrich carrying in its stomach about 1 kg of stones.

Contrary to popular belief, ostriches do not bury their heads in the sand to avoid danger. This may have been a misunderstanding of their sticking their heads in the sand to swallow sand and pebbles to help digest their fibrous food, or, as National Geographic suggests, of the defensive behavior of lying low, so that they may appear from a distance to have their head buried. Another possible origin for the myth lies with the fact that ostriches keep their eggs in holes in the sand instead of nests, and must rotate them using their beaks during incubation; digging the hole, placing the eggs, and rotating them might each be mistaken for an attempt to bury their heads in the sand.