Flightless bird also included here. Flightless bird Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species including the well known ratites (ostrich, emu, cassowary, rhea and kiwi) and penguins. The smallest flightless bird is the Inaccessible Island rail (length 12.5 cm, weight 34.7 g). The largest (both heaviest and tallest) flightless bird, which is also the largest living bird, is the ostrich (2.7 m, 156 kg). Ostriches are farmed for their decorative feathers, meat and their skins, which are used to make leather. Many domesticated birds, such as the domestic chicken and domestic
Palaeognathae flying birds that were common in the Cenozoic of the northern hemisphere, were also paleognaths. He argues that the lithornithiform bird "Paleotis", known from fossils in Denmark (northern hemisphere), shared unique anatomical features of the skull that make it a member of the same order as the ostriches. He also argued that the kiwis should not have reached New Zealand, which moved away from the mainland in the Early Cretaceous, if their ancestor was flightless; this claim at least has been vindicated by the discovery of the possibly volant "Proapteryx". He therefore deduced that lithornithiform ancestors could have reached the