Ostrich in the setting sun. The ostrich is a large flightless bird that is native to Africa. It is the largest living species of bird and is the only living member of the genus Struthio. Ostriches are classified as ratites, which are a group of birds that have evolved from the dinosaurs. They have a long neck, powerful legs, and a small head. Ostriches can run up to 43 mph and can cover distances of up to 5 miles in a single day. They are herbivores and eat a variety of plants, including grasses, leaves, fruits, and seeds. Ostriches live in groups called herds which can number from 10 to 100 birds. The eggs of ostriches are the largest eggs of any living bird species.