The ostrich is unlike other birds in many important characters. It is not a typical bird. While it has feathers and wings, its feathering is not normal, and the muscles of the wings are lacking. In the minds of most persons it is associated with the circus menagerie rather than with the poultry yard, but, as we shall see, this singular bird has a place in domestication and, as a useful land bird, belongs to the poultry group. There are two species of ostriches, but only one of these is of economic value. =Description.= The ostrich is the largest of living birds. A full-grown male standing erect measures from six to seven feet in height. The largest specimens weigh about three hundred pounds. As, in the atmosphere which now surrounds the earth, a creature of such size and weight cannot fly at all, the wings of the ostrich have become atrophied, and the muscles of the wings, which form the plump, meaty breasts of flying birds, are entirely wanting. Not only have these muscles disappeared, but the breastbone, which in flying birds is very large in proportion to the rest of the skeleton, and has a deep, longitudinal keel in the middle, is comparatively small in the ostrich and has no keel at all. The ostrich, having no power of flight, is dependent for safety upon its speed in running; so its legs are long and strong, and the muscles which move them are very large. Indeed, there is very little meat on an ostrich except on the thighs. It can run much faster than a horse. Because its foot must be adapted to running at great speed, the ostrich has only two toes. Its neck is very long and slender, and its head is very small and flat. In such a head there is little room for brains. The ostrich is a very stupid creature, but it does not, as is commonly supposed, hide its head in the sand and imagine that, not being able to see its enemies, it cannot be seen by them. That is a myth apparently based upon the fact that, when in repose, an ostrich sometimes lies with its long neck stretched upon the ground. [Illustration: Fig. 179. Side view of male ostrich. (Photograph from the Bureau of Animal Industry, United States Department of Agriculture)] Since the wings of the ostrich are useless for flight, the flight feathers have lost the structure adapted to that purpose and have developed into beautiful plumes. The tail feathers have also undergone a similar change. These wing and tail feathers are the ostrich feathers of commerce. The neck and head of the ostrich are almost bare of feathers. The body is covered with feathers, but not as densely as in most birds. There are just enough feathers on the body of an ostrich to protect the skin from exposure when they lie flat. The areas on the skin where there are no feathers are much larger than on other birds. The thighs of the ostrich are bare. The skin is in some varieties of a bluish-gray; in other varieties the bare parts are red and the skin of the body is yellow.