OSTRICH

Ostriches (Struthio camelus); at left is the male (Struthio camelus), largest living bird, a flightless species found in Africa. It belongs to the family Struthionidae, order Struthioniformes. The adult male may be 2.5 m (nearly 8 feet) tallalmost half of its height is neckand weigh 155 kg (345 pounds); the female is somewhat smaller. The ostrich's egg, averaging about 150 mm (6 inches) in length by 125 mm (5 inches) in diameter and weighing up to 1.35 kg (3 pounds), is presently the world's largest. The male is mostly black but has white plumes in the wings and tail; females are mostly brown. The head and most of the neck, reddish to bluish in colour, is lightly downed; the legs, including the powerful thighs, are naked. The head is small, the bill short and rather wide; the big brown eyes have thick black lashes. The ostrich lives in flocks of 5 to 50, usually in the company of grazing animals. The ostrich relies on its strong legsuniquely two-toed, with the main toe developed almost as a hoofto escape its enemies, chiefly humans and the larger carnivores. A frightened ostrich can achieve a speed of 65 km per hour (40 miles per hour). If cornered it can deliver dangerous kicks. Ostriches live mainly on plant matter but take some animal food; they can go without water for long periods. Breeding males emit roars and hisses as they fight for a harem of three to five hens. The communal nest scraped in the ground may contain 15 to 60 shiny, whitish eggs. The male sits by night; the females take turns by day. The chicks hatch in about 40 days and when a month old can keep up with running adults. To escape detection, chicks as well as adults may lie on the ground with neck outstretched, a habit that may have given rise to the legend that the ostrich buries its head in the sand when danger threatens. Ostrich plumes adorned the helmets of medieval European knights, and in the 19th century such plumes were sold for women's finery. This demand led to the establishment of ostrich farms in South Africa, the southern United States, Australia, and elsewhere, but the trade collapsed after World War I. The hide provides a soft, fine-grained leather. Ostriches have been trained for saddle and sulky racing, but they tire easily and are not well suited for training. They do well in captivity and may live 50 years. The ostrich is typical of a special group of flightless birds (see ratite). The forms, differing slightly in skin colour, size, and egg features, formerly were considered separate species but are merely races of S. camelus. Most familiar is the North African ostrich, S. camelus camelus, ranging, in much-reduced numbers, from Morocco to The Sudan. The Syrian ostrich, S. camelus syriacus, of Syria and Arabia became extinct in 1941. Fossil ostriches are known from Early Pliocene rock (about 5 million years old) from southern Russia, India, and north-central China.