Ostriches are large

flightless Flightless birds are birds that through evolution lost the ability to fly. There are over 60 extant species, including the well known ratites ( ostriches, emu, cassowaries, rheas, and kiwi) and penguins. The smallest flightless bird is ...

birds of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial n ...

''Struthio'' in the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Struthioniformes, part of the infra-class

Palaeognathae Palaeognathae (; ) is a infraclass of birds, called paleognaths, within the class Aves of the clade Archosauria. It is one of the two extant infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae con ...

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

emu The emu () (''Dromaius novaehollandiae'') is the second-tallest living bird after its ratite relative the ostrich. It is endemic to Australia where it is the largest native bird and the only extant member of the genus '' Dromaius''. The ...

s, rheas, and

kiwi Kiwi most commonly refers to: * Kiwi (bird), a flightless bird native to New Zealand * Kiwi (nickname), a nickname for New Zealanders * Kiwifruit, an edible berry * Kiwi dollar or New Zealand dollar, a unit of currency Kiwi or KIWI may also ref ...

s. There are two living species of ostrich: the

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

, native to large areas of sub-Saharan Africa and the

Somali ostrich The Somali ostrich (''Struthio molybdophanes''), also known as the blue-necked ostrich, is a large flightless bird native to the Horn of Africa. It is one of two living species of ostriches, the other being the common ostrich. It was also previou ...

, 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), ...

. The common ostrich was also historically native to the Arabian Peninsula, and ostriches were present across Asia as far east as Mongolia during the

Late Pleistocene The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch within ...

and possibly into the

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

. They lay the largest eggs of any living land animal. With the ability to run at 70 km/h (43.5 mph), they are the fastest birds on land. They are farmed worldwide, particularly for their feathers as they are used as decoration and feather dusters. Their skin is also used for leather products. They are the heaviest living birds.

Taxonomic history

The genus ''Struthio'' was first described by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, ...

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

, rhea, and

cassowary Cassowaries ( tpi, muruk, id, kasuari) are flightless birds of the genus ''Casuarius'' in the order Casuariiformes. They are classified as ratites (flightless birds without a keel on their sternum bones) and are native to the tropical ...

, 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.Birdlife International (2012)

Evolution

Struthionidae Struthionidae (; ) is a family of flightless birds, containing the extant ostriches and their extinct relatives. The two extant species of ostrich are the common ostrich and Somali ostrich, both in the genus ''Struthio'', which also contains seve ...

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

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

, 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 in the geologic time scale that extends from 5.333 million to 2.58 The earliest fossils of the genus ''Struthio'' are from the early

Miocene The Miocene ( ) is the first 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 means "less recent" ...

~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, 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 in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

, 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) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to ...

s and the

Sahel The Sahel (; ar, ساحل ' , "coast, shore") is a region in North Africa. It is defined as the ecoclimatic and biogeographic realm of transition between the Sahara to the north and the Sudanian savanna to the south. Having a hot semi-arid c ...

, both north and south of the equatorial forest zone. The

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. In the past it was considered to be part of a ...

. 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 ostrich The Arabian ostrich (''Struthio camelus syriacus''), Syrian ostrich, or Middle Eastern ostrich is an extinct subspecies of the ostrich that lived on the Arabian Peninsula and in the Near East until the mid-20th century. Distribution Its range ...

es in

Asia Minor Anatolia, tr, Anadolu Yarımadası), and the Anatolian plateau, also known as Asia Minor, is a large peninsula in Western Asia and the westernmost protrusion of the Asian continent. It constitutes the major part of modern-day Turkey. The ...

and

Arabia The Arabian Peninsula, (; ar, شِبْهُ الْجَزِيرَةِ الْعَرَبِيَّة, , "Arabian Peninsula" or , , "Island of the Arabs") or Arabia, is a peninsula of Western Asia, situated northeast of Africa on the Arabian Plate. ...

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

Israel Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ...

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 some ...

populations.

Species

In 2008, ''S. linxiaensis'' was transferred to the genus ''

Orientornis ''Orientornis'' is an extinct species of ratite from the Miocene of China. Description Remains of a pelvis, including a synsacrum, were recovered from mudstone in the Linxia Basin, Guanghe County, Gansu Province, northwest China. Based on the si ...

.'' Three additional species, ''S. pannonicus'', ''S. dmanisensis'', and ''S. transcaucasicus'', were transferred to the genus '' Pachystruthio'' in 2019. Several additional fossil forms are ichnotaxa (that is, classified according to the organism's

trace fossil A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, ...

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 Ostriches are large flightless birds of the genus ''Struthio'' in the order Struthioniformes, part of the infra-class Palaeognathae, a diverse group of flightless birds also known as ratites that includes the emus, rheas, and kiwis. There are t ...

'' (Brandt 1873) Lambrecht 1921 (Pliocene of SE Europe to WC Asia) – oospecies ** †''

Struthio coppensi ''Struthio coppensi'' is an extinct species of ostrich located near Elisabethfeld, Namibia. This ostrich is believed to have lived during the Miocene, about 20 mya, and is the oldest member of the ''Struthio'' genus Genus ( plural genera ) i ...

'' Mourer-Chauviré et al. 1996 (Early Miocene of Elizabethfeld, Namibia) ** †''

Struthio daberasensis Ostriches are large flightless birds of the genus ''Struthio'' in the order Struthioniformes, part of the infra-class Palaeognathae, a diverse group of flightless birds also known as ratites that includes the emus, rheas, and kiwis. There are ...

'' Pickford, Senut & Dauphin 1995 (Early – Middle Pliocene of Namibia) – oospecies ** †''

Struthio epoasticus Ostriches are large flightless birds of the genus ''Struthio'' in the order Struthioniformes, part of the infra-class Palaeognathae, a diverse group of flightless birds also known as ratites that includes the emus, rheas, and kiwis. There are ...

'' Bonaparte 1856 ** †''

Struthio kakesiensis ''Struthio kakesiensis'' is an extinct oospecies of ratite bird known from eggshell fossils found in Laetoli, Tanzania. It was related to the modern day ''Struthio Ostriches are large flightless birds of the genus ''Struthio'' in the order S ...

'' 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 Ostriches are large flightless birds of the genus ''Struthio'' in the order Struthioniformes, part of the infra-class Palaeognathae, a diverse group of flightless birds also known as ratites that includes the emus, rheas, and kiwis. There are ...

'' Lowe 1933 (Late Pleistocene of Tanzania) – probably subspecies of ''S. camelus'' ** †''

Struthio orlovi ''Struthio orlovi'' is an extinct species of ratite bird from the Miocene of Moldavia Moldavia ( ro, Moldova, or , literally "The Country of Moldavia"; in Romanian Cyrillic: or ; chu, Землѧ Молдавскаѧ; el, Ἡγεμον� ...

'' 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)J. G. Andersson, Essays on the cenozoic of northern China. ''Memoirs of the Geological Survey of China (Peking)'', Series A, No. 3 (1923), pp. 1–152, especially pp. 53–77: "On the occurrence of fossil remains of Struthionidae in China."; and J. G. Andersson, Research into the prehistory of the Chinese. Bulletin of the Museum of Far Eastern Antiquities 15 (1943), 1–300, plus 200 plates. oospecies(?) ** †''

Struthio asiaticus The Asian or Asiatic ostrich (''Struthio asiaticus''), is an extinct species of ostrich that lived during the Neogene period on the Indian subcontinent. The early records that ranged from the Pliocene epoch in Africa to Pleistocene-Holocene epoc ...

'' Brodkorb 1863, Asian ostrich (Early Pliocene – Early Holocene of Central Asia to China? and Morocco) ** '' Struthio camelus'',

*** ''

Struthio camelus camelus The North African ostrich, red-necked ostrich, or Barbary ostrich (''Struthio camelus camelus'') is the nominate subspecies of the common ostrich from West and North Africa. It is the largest subspecies, making it the largest living bird. Evolu ...

'', North African ostrich *** ''

Struthio camelus massaicus The Masai ostrich (''Struthio camelus massaicus''), also known as the East African ostrich is a red-necked subspecies variety of the common ostrich and is endemic to East Africa. It is one of the largest birds in the world, second only to its sis ...

'', Masai ostrich *** ''

Struthio camelus australis The South African ostrich (''Struthio camelus australis''), also known as the black-necked ostrich, Cape ostrich or southern ostrich is a subspecies of the common ostrich endemic to Southern Africa. It is widely farmed for its meat, eggs and feat ...

'',

South African ostrich The South African ostrich (''Struthio camelus australis''), also known as the black-necked ostrich, Cape ostrich or southern ostrich is a subspecies of the common ostrich endemic to Southern Africa. It is widely farmed for its meat, eggs and feat ...

*** †''

Struthio camelus syriacus The Arabian ostrich (''Struthio camelus syriacus''), Syrian ostrich, or Middle Eastern ostrich is an extinct subspecies of the Common ostrich, ostrich that lived on the Arabian Peninsula and in the Near East until the mid-20th century. Distribut ...

'',

** ''

Struthio molybdophanes The Somali ostrich (''Struthio molybdophanes''), also known as the blue-necked ostrich, is a large flightless bird native to the Horn of Africa. It is one of two living species of ostriches, the other being the common ostrich. It was also previo ...

'',

Citations

General references

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