Ostriches are large

flightless Flightless birds are birds that cannot fly, as they have, through evolution, lost the ability to. There are over 60 extant species, including the well-known ratites ( ostriches, emus, cassowaries, rheas, and kiwis) and penguins. The smal ...

birds Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

. Two living species are recognised, the

common ostrich The common ostrich (''Struthio camelus''), or simply ostrich, is a species of flightless bird native to certain areas of Africa. It is one of two extant species of ostriches, the only living members of the genus ''Struthio'' in the ratite group ...

, native to large parts of

sub-Saharan Africa Sub-Saharan Africa is the area and regions of the continent of Africa that lie south of the Sahara. These include Central Africa, East Africa, Southern Africa, and West Africa. Geopolitically, in addition to the list of sovereign states and ...

, and the Somali ostrich, native to the

Horn of Africa The Horn of Africa (HoA), also known as the Somali Peninsula, is a large peninsula and geopolitical region in East Africa.Robert Stock, ''Africa South of the Sahara, Second Edition: A Geographical Interpretation'', (The Guilford Press; 2004), ...

. They are the heaviest and largest living birds, with adult common ostriches weighing anywhere between 63.5 and 145 kilograms and laying the largest eggs of any living land animal.Del Hoyo, Josep, et al. Handbook of the birds of the world. Vol. 1. No. 8. Barcelona: Lynx edicions, 1992. With the ability to run at 70 km/h (43.5 mph), they are the fastest birds on land. They are farmed worldwide, with significant industries in the Philippines and in Namibia.

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

produces about 70% of global ostrich products, with the industry largely centered around the town of Oudtshoorn. Ostrich leather is a lucrative commodity, and the large feathers are used as plumes for the decoration of ceremonial headgear. Ostrich eggs and

meat Meat is animal Tissue (biology), tissue, often muscle, that is eaten as food. Humans have hunted and farmed other animals for meat since prehistory. The Neolithic Revolution allowed the domestication of vertebrates, including chickens, sheep, ...

have been used by humans for millennia. Ostrich oil is another product that is made using ostrich fat. Ostriches are of the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

''Struthio'' in the order

Struthioniformes Struthioniformes is an order of birds with only a single extant family, Struthionidae, containing the ostriches. Several other extinct families are known, spanning across the Northern Hemisphere, from the Early Eocene to the early Pliocene, incl ...

, part of the infra-class

Palaeognathae Palaeognathae (; ) is an infraclass of birds, called paleognaths or palaeognaths, within the class Aves of the clade Archosauria. It is one of the two extant taxon, extant infraclasses of birds, the other being Neognathae, both of which form Neo ...

, a diverse group of flightless birds also known as ratites that includes the

emu The emu (; ''Dromaius novaehollandiae'') is a species of flightless bird endemism, endemic to Australia, where it is the Tallest extant birds, tallest native bird. It is the only extant taxon, extant member of the genus ''Dromaius'' and the ...

s, rheas, cassowaries, kiwis and the extinct elephant birds and moas. The common ostrich was historically native to the

Arabian Peninsula The Arabian Peninsula (, , or , , ) or Arabia, is a peninsula in West Asia, situated north-east of Africa on the Arabian plate. At , comparable in size to India, the Arabian Peninsula is the largest peninsula in the world. Geographically, the ...

, and ostriches were present across Asia as far east as China and Mongolia during the

Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...

and possibly into the

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

Taxonomic history

The genus ''Struthio'' was first described by

Carl Linnaeus Carl Linnaeus (23 May 1707 – 10 January 1778), also known after ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

in 1758. The genus was used by Linnaeus and other early taxonomists to include the

, rhea, and cassowary, until they each were placed in their own genera. The Somali ostrich (''Struthio molybdophanes'') has recently become recognized as a separate species by most authorities, while others are still reviewing the evidence.

Evolution

Struthionidae is a member of the

, a group of paleognath birds which first appeared during the Early

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

, and includes a variety of flightless forms which were present across the Northern Hemisphere (Europe, Asia and North America) during the Eocene epoch. The closest relatives of Struthionidae within the Struthioniformes are the Ergilornithidae, known from the late Eocene to early

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58 The earliest fossils of the genus ''Struthio'' are from the early

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

~21 million years ago of Namibia in Africa, so it is proposed that genus is of African origin. By the middle to late

(5–13 mya) they had spread to and become widespread across Eurasia. While the relationship of the African fossil species is comparatively straightforward, many Asian species of ostrich have been described from fragmentary remains, and their interrelationships and how they relate to the African ostriches are confusing. In India, Mongolia and

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

, ostriches are known to have become extinct only around, or even after, the end of the last ice age; images of ostriches have been found prehistoric Chinese pottery and

petroglyph A petroglyph is an image created by removing part of a rock surface by incising, picking, carving, or abrading, as a form of rock art. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions ...

s. File: Struthio camelus MHNT.ZOO.2010.11.1.1.jpg, ''Struthio camelus'' egg – MHNT File:Ostrich & chicken egg comparison.jpg, Size comparison (with a chicken egg and a US dollar bill) File:Ostrich with eggs.jpg, Ostrich with eggs

Distribution and habitat

Today, ostriches are only found natively in the wild in

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

, where they occur in a range of open arid and semi-arid habitats such as

savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) biome and ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach th ...

s and the

Sahel The Sahel region (; ), or Sahelian acacia savanna, is a Biogeography, biogeographical region in Africa. It is the Ecotone, transition zone between the more humid Sudanian savannas to its south and the drier Sahara to the north. The Sahel has a ...

, both north and south of the equatorial forest zone. The Somali ostrich occurs in the

, having evolved isolated from the common ostrich by the geographic barrier of the

East African Rift The East African Rift (EAR) or East African Rift System (EARS) is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. It was formerly considered to be part of a l ...

. In some areas, the common ostrich's Masai subspecies occurs alongside the Somali ostrich, but they are kept from interbreeding by behavioral and ecological differences. The Arabian ostriches in

Asia Minor Anatolia (), also known as Asia Minor, is a peninsula in West Asia that makes up the majority of the land area of Turkey. It is the westernmost protrusion of Asia and is geographically bounded by the Mediterranean Sea to the south, the Aegean ...

and

Arabia The Arabian Peninsula (, , or , , ) or Arabia, is a peninsula in West Asia, situated north-east of Africa on the Arabian plate. At , comparable in size to India, the Arabian Peninsula is the largest peninsula in the world. Geographically, the ...

were hunted to extinction by the middle of the 20th century, and in

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

attempts to introduce North African ostriches to fill their ecological role have failed. Escaped common ostriches in Australia have established

feral A feral (; ) animal or plant is one that lives in the wild but is descended from domesticated individuals. As with an introduced species, the introduction of feral animals or plants to non-native regions may disrupt ecosystems and has, in som ...

populations.

Species

In 2008, ''S. linxiaensis'' was transferred to the genus '' Orientornis.'' Three additional species, ''S. pannonicus'', ''S. dmanisensis'', and ''S. transcaucasicus'', were transferred to the genus ''

Pachystruthio ''Pachystruthio'' is a genus of extinct bird which lived in Eurasia from the Late Pliocene to the Middle Pleistocene. Its fossils have been found in Hungary, Greece Crimea, Georgia (country), Georgia, and China. The genus contains three species: ...

'' in 2019. Several additional fossil forms are ichnotaxa (that is, classified according to the organism's

trace fossil A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with body fossils, which are the fossilized remains of part ...

s such as footprints rather than its body) and their association with those described from distinctive bones is contentious and in need of revision pending more good material. The species are: *Prehistoric ** †'' Struthio barbarus'' Arambourg 1979 ** †'' Struthio brachydactylus'' Burchak-Abramovich 1939 (Pliocene of Ukraine) ** †'' Struthio chersonensis'' (Brandt 1873) Lambrecht 1921 (Pliocene of SE Europe to WC Asia) – oospecies ** †'' Struthio coppensi'' Mourer-Chauviré et al. 1996 (Early Miocene of Elizabethfeld, Namibia) ** †'' Struthio daberasensis'' Pickford, Senut & Dauphin 1995 (Early – Middle Pliocene of Namibia) – oospecies ** †'' Struthio kakesiensis'' Harrison & Msuya 2005 (Early Pliocene of Laetoli, Tanzania) – oospecies ** †'' Struthio karingarabensis'' Senut, Dauphin & Pickford 1998 (Late Miocene – Early Pliocene of SW and CE Africa) – oospecies(?) ** †'' Struthio oldawayi'' Lowe 1933 (Late Pleistocene of Tanzania) – probably subspecies of ''S. camelus'' ** †'' Struthio orlovi'' Kuročkin & Lungo 1970 (Late Miocene of Moldavia) ** †'' Struthio wimani'' Lowe 1931 (Early Pliocene of China and Mongolia) *

** †'' Struthio anderssoni'' Lowe 1931, East Asian ostrich (Late Pleistocene of China to Mongolia) ** †'' Struthio asiaticus'' Brodkorb 1863, Asian ostrich (Early Pliocene – Early Holocene of Central Asia to China? and Morocco) ** '' Struthio camelus'',

*** '' Struthio camelus camelus'', North African ostrich *** '' Struthio camelus massaicus'', Masai ostrich *** '' Struthio camelus australis'', South African ostrich *** †'' Struthio camelus syriacus'', Arabian ostrich ** '' Struthio molybdophanes'', Somali ostrich

Citations

General references

* * * * * * {{Authority control Extant Miocene first appearances Flightless birds Miocene birds Ratites Taxa named by Carl Linnaeus