Ostriches are the tallest, heaviest birds alive today
Struthio camelus, the common ostrich of African open country, cannot fly yet outruns most predators. Males stand about 2.1 to 2.75 meters and may weigh 100 to 130 kilograms, while farms worldwide harvest feathers, leather, and meat from the giants.
This flightless species belongs to Struthioniformes; older schemes swept all ratites into that order, though modern classifications narrow the grouping. Diet is mainly plants plus invertebrates and small reptiles. Birds move in nomadic groups that exploit shifting food and water. Humans raise them for decorative plumes, dusters, hides, and steaks far from ancestral ranges.
It once ranged across Africa north and south of the Sahara, much of Asia Minor and Arabia; DNA from fossil eggshells at eight sites in Rajasthan, Gujarat and Madhya Pradesh shows ostriches lived in India some 25,000 years ago. Genetic work also showed the old ratite order was not a natural group, so ostriches now stand alone in Struthioniformes. Linnaeus named the species, and camelus nods to the Greek strouthokamelos, camel-sparrow, for its dry habitat. Farmed birds released in Australia left a small feral population in the outback.
Its eyes, 50 millimetres across, are the largest of any land vertebrate, and the head can sit 2.8 metres above the ground. The feathers lack the hooks that zip flight feathers together, so they insulate instead, and the flat breastbone has no keel for wing muscles. Unlike every other living bird, it passes urine separately from faeces. When chased it can top 70 kilometres per hour and cruise at 50, the fastest two-legged animal, and a forward-only kick can deliver about 225 kilograms of force. Groups of 5 to 50 are typical, but outside the breeding season most sightings are of pairs or lone birds.
Source: Common ostrich
