information:filtering, structural:summarization
Subspecies

Four subspecies are recognized:

Some analyses indicate that the Somali ostrich is now considered a full species; the Tree of Life Project, The Clements Checklist of Birds of the World, BirdLife International, and the IOC World Bird List recognize it as a different species. A few authorities, including the Howard and Moore Complete Checklist of the Birds of the World, do not recognize it as separate. Mitochondrial DNA haplotype comparisons suggest that it diverged from the other ostriches not quite 4 mya due to formation of the East African Rift. Hybridization with the subspecies that evolved southwestwards of its range, S. c. massaicus, has apparently been prevented from occurring on a significant scale by ecological separation; the Somali ostrich prefers bushland where it browses middle-height vegetation for food while the Masai ostrich is, like the other subspecies, a grazing bird of the open savanna and miombo habitat.

The population from Río de Oro was once separated as Struthio camelus spatzi because its eggshell pores were shaped like a teardrop and not round. As there is considerable variation of this character and there were no other differences between these birds and adjacent populations of S. c. camelus, the separation is no longer considered valid. However, a study analysing the postcranial skeleton of all living and recently extinct species and subspecies of ostriches appeared to validate S. c. spatzi based on its unique skeletal proportions. This population disappeared in the latter half of the 20th century. There were 19th-century reports of the existence of small ostriches in North Africa; these are referred to as Levaillant's ostrich (Struthio bidactylus) but remain a hypothetical form not supported by material evidence.