The Ostrich is one or two species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of large flightless bird
Flightless bird
Flightless birds are birds which lack the ability to fly, relying instead on their ability to run or swim. They are thought to have evolved from flying ancestors. There are about forty species in existence today, the best known being the ostrich, emu, cassowary, rhea, kiwi, and penguin...

s native to Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

, the only living member(s) of the genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

Struthio is a genus of bird in the order Struthioniformes.-Species:There are ten known species from this genus, of which eight are extinct. There are five more possible species of which trace fossils have been found...

. Some analyses indicate that the Somali Ostrich
Somali Ostrich
The Somali Ostrich is a large flightless bird, a distinct subspecies, sometimes considered a full species, of the Ostrich.-Taxonomy:...

 may be better considered a full species apart from the Common Ostrich, but most taxonomists consider it to be a subspecies.

Ostriches share the order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Struthioniformes with the kiwi
Kiwi are flightless birds endemic to New Zealand, in the genus Apteryx and family Apterygidae.At around the size of a domestic chicken, kiwi are by far the smallest living ratites and lay the largest egg in relation to their body size of any species of bird in the world...

s, emus, and other ratite
A ratite is any of a diverse group of large, flightless birds of Gondwanan origin, most of them now extinct. Unlike other flightless birds, the ratites have no keel on their sternum—hence the name from the Latin ratis...

s. It is distinctive in its appearance, with a long neck and legs and the ability to run at maximum speeds of about 70 kilometres per hour (43.5 mph), the top land speed of any bird.