The reduced number of toes is an adaptation that appears to aid in running, useful for getting away from predators. The bird has just two toes on each foot (most birds have four), with the nail on the larger, inner toe resembling a hoof. The tarsus of the common ostrich is the largest of any living bird, measuring 39 to 53 cm ( 15 + 1⁄ 2 to 21 in) in length. The strong legs of the common ostrich are unfeathered and show bare skin, with the tarsus (the lowest upright part of the leg) being covered in scales: red in the male, black in the female.
HANDBOOK OF THE BIRDS OF THE WORLD OSTRICH SKIN
Their skin varies in color depending on the subspecies, with some having light or dark gray skin and others having pinkish or even reddish skin. However, the head and bill are relatively small for the birds' huge size, with the bill measuring 12 to 14.3 cm ( 4 + 3⁄ 4 to 5 + 3⁄ 4 in). The eyes are shaded from sunlight from above. The long neck and legs keep their head up to 2.8 m (9 ft 2 in) above the ground, and their eyes are said to be the largest of any land vertebrate – 50 mm (2 in) in diameter – helping them to see predators at a great distance. The skin of the female's neck and thighs is pinkish gray, while the male's is gray or pink dependent on subspecies. The head and neck of both male and female ostriches is nearly bare, with a thin layer of down. Females and young males are grayish-brown and white. However, the tail of one subspecies is buff. The feathers of adult males are mostly black, with white primaries and a white tail. At one year of age, common ostriches weigh approximately 45 kilograms (100 lb). During the first year of life, chicks grow at about 25 cm (10 in) per month. New chicks are fawn in color, with dark brown spots. At sexual maturity (two to four years), male common ostriches can be from 2.1 to 2.8 m (6 ft 11 in to 9 ft 2 in) in height, while female common ostriches range from 1.7 to 2.0 m (5 ft 7 in to 6 ft 7 in) tall. Exceptional male ostriches (in the nominate subspecies) can weigh up to 156.8 kg (346 lb). camelus), was found to average 111 kg (245 lb) in unsexed adults. massaicus) average 115 kg (254 lb) in males and 100 kg (220 lb) in females, while the nominate subspecies, the North African ostrich ( S. Ĭommon ostriches usually weigh from 63 to 145 kilograms (139–320 lb), or as much as one to two adult humans. Its skin is used for leather products and its meat is marketed commercially, with its leanness a common marketing point. The common ostrich is farmed around the world, particularly for its feathers, which are decorative and are also used as feather dusters. Mating patterns differ by geographical region, but territorial males fight for a harem of two to seven females. If cornered, it can attack with a kick of its powerful legs. When threatened, the ostrich will either hide itself by lying flat against the ground or run away. It lives in nomadic groups of 5 to 50 birds. The common ostrich's diet consists mainly of plant matter, though it also eats invertebrates and small reptiles. The common ostrich is the largest living species of bird and lays the largest eggs of any living bird (the extinct elephant birds of Madagascar and the giant moa of New Zealand laid larger eggs).
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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. 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. 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. Struthioniformes previously contained all the ratites, such as the kiwis, emus, rheas, and cassowaries. The common ostrich belongs to the order Struthioniformes. 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 very distinctive subspecies of ostrich.
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It is one of two extant species of ostriches, the only living members of the genus Struthio in the ratite order of birds. 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. syriacus Rothschild, 1919 Arabian ostrich australis Gurney, 1868 South African ostrich camelus Linnaeus, 1758 North African ostrich