Naturalists now recognise four kinds of African ostriches, which, although generally classed as distinct species, might perhaps be better regarded as local races of a single specific type. These, regarded as species, comprise the typical red-legged and red-thighed North African ostrich (_Struthio camelus_), ranging into Palestine and Arabia, and laying thickly pitted eggs; the Somali ostrich (_S. molybdophanes_), characterised by its bluish grey neck and thighs; the Masai ostrich (_S. masaicus_) of East Africa, with the bare parts red, the body-plumage of the cocks brownish black in place of black, and the eggs pitted; and, lastly, the South African _S. australis_, which lays smooth-shelled eggs and has the neck and thighs light bluish grey. In the Somali ostrich, which inhabits Somaliland and western Gallaland as far as the Juba River, the colour of the bare parts of the body may best be described as grey or slaty blue, while the margins of the beak and the front surfaces of the lower part of the legs are dull vermilion. Ostriches are essentially gregarious birds, associating either in small family parties comprising five or six birds, or in large flocks, which in East Africa mingle freely with herds of hartebeests, gnus, and bontequaggas. They require a wide extent of open country, with grass and, above all, water, of which they drink frequently and copiously. Although ostriches feed chiefly upon vegetable substances, they likewise consume worms, insects, molluscs, reptiles, and probably also small birds and mammals, while in captivity they will swallow almost anything that is offered them, including nails, keys, and copper coins. In a state of nature they swallow sand, earth, and small stones, in order to assist the action of their gizzards. [Illustration] The cocks appear to be polygamous, although some doubt has been expressed as to whether this is really the case; and it seems certain that several hens lay in the same nest, where as many as thirty eggs may be laid in a slight hollow in the sand. Incubation is undertaken by the cock alone, and it is he who looks after the chicks, which he tends with remarkable care. The chicks when they escape from the eggs (each of which weighs as much as twenty-four hens’ eggs) are as large as hens; and, with their bristly feather-quills, are rather suggestive of two-legged hedgehogs.