_Struthio camelus_, the Ostrich or "Camel-bird" of North Africa, now extends from Barbary to Arabia, and even to Mesopotamia, though no longer found, as of old, in Egypt or Central Asia, its former occurrence in Baluchistan being somewhat open to question. It is black with white wings and tail, having a flesh-coloured neck covered with brownish down, and partially bare tibiae of the same hue. The female and young male are almost entirely cinereous, while the chicks are clothed with bristly yellowish-white down with blackish stripes. The eggs of the typical northern bird have a surface like ivory, while those from Southern Africa are marked with close-set pits, whence some authorities recognise a different species (_S. australis_) in the latter region, distinguishable, moreover, by the bluish colour of the naked parts. Examples from Somaliland and the adjoining districts of East Africa to Lake Tanganyika are separated as _S. molybdophanes_, on account of the leaden colour of the unfeathered portions, coupled with a red patch on the front of the metatarsus. The eggs are smoother than in the southern species, but similarly pitted. The fossil forms _S. asiaticus_ from the Pliocene of the Siwalik Hills of India, and _S. karatheodori_ from the Upper Miocene of Samos complete the family, while _S._ (_Struthiolithus_) _chersonensis_ has been founded on a petrified egg from the government of Cherson in South Russia. {28}[Illustration: FIG. 8.–Ostrich. _Struthio camelus._ × 1/19.] The Ostrich stands about eight feet high, being the largest of existing birds; it frequents sandy wastes and dry arid localities, such as are found in the Sahara and the plains and valleys of Southern Africa, while districts studded with low bushes are not unfrequently tenanted. Though the fable of the head being hidden to avoid detection is of course devoid of foundation, this species is timid and wild in its native haunts, and being keen-sighted as well as wary, gives an impression of great restlessness. From the fact that a single stride is said to cover twenty-five feet or more, it will readily be understood that the speed is very great, exceeding that of a galloping horse; but, owing to its habit of running in a curve, it is generally possible to intercept the bird's path at a distance from the point where it started. In motion the head is held forward, and the wings are outspread, while both beak and feet are used as weapons of defence when capture is imminent, the latter delivering strong sideways kicks, which make close quarters very dangerous. Forty or fifty individuals may at times be seen in company; the usual parties, however, consist of five or six at most, especially during the breeding season, when the polygamous cock escorts a flock of several hens, obtained by battle or allured by courting performances earlier in the season. A liking for the companionship of zebras, hartebeests and other antelopes, has been noticed by various observers.