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.[3] With the ability to run at 70km/h (43.5mph),[4] they are the fastest birds on land. They are farmed worldwide, with significant industries in the Philippines and in Namibia. South Africa produces about 70% of global ostrich products,[5] 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 have been used by humans for millennia. Ostrich oil is another product that is made using ostrich fat.
The common ostrich was historically native to the Arabian Peninsula, and ostriches were present across Asia as far east as China and Mongolia during the Late Pleistocene and possibly into the Holocene.
Mating dance of the Ostrich.
Taxonomic history
The genus Struthio was first described by Carl Linnaeus in 1758. The genus was used by Linnaeus and other early taxonomists to include the emu, rhea, and cassowary, until they each were placed in their own genera.[2] The Somali ostrich (Struthio molybdophanes) has recently become recognized as a separate species by most authorities, while others are still reviewing the evidence.[6][7]
Evolution
Struthionidae is a member of the Struthioniformes, a group of paleognath birds which first appeared during the Early Eocene, 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 of Asia. It is therefore most likely that Struthionidae originated in Asia.[8]
The earliest fossils of the genus Struthio are from the early Miocene ~21 million years ago of Namibia in Africa, so it is proposed that genus is of African origin. By the middle to late Miocene (5–13 mya) they had spread to and become widespread across Eurasia.[9] 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 petroglyphs.[10][11][12][13]
Size comparison (with a chicken egg and a US dollar bill)
Ostrich with eggs
Distribution and habitat
Today, ostriches are only found natively in the wild in Africa, where they occur in a range of open arid and semi-arid habitats such as savannas and the Sahel, both north and south of the equatorial forest zone.[14] The Somali ostrich occurs in the Horn of Africa, having evolved isolated from the common ostrich by the geographic barrier of the East African Rift. 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.[15] The Arabian ostriches in Asia Minor and Arabia were hunted to extinction by the middle of the 20th century, and in Israel attempts to introduce North African ostriches to fill their ecological role have failed.[16] Escaped common ostriches in Australia have established feral populations.[17][18][19]
Species
A male Somali ostrich in a Kenyansavanna, showing its blueish neck
In 2008, S. linxiaensis was transferred to the genus Orientornis.[20] Three additional species, S. pannonicus, S. dmanisensis, and S. transcaucasicus, were transferred to the genus Pachystruthio in 2019.[21] Several additional fossil forms are ichnotaxa (that is, classified according to the organism's trace fossils 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.[22]
1 2 Janz, Lisa; etal. (2009). "Dating North Asian surface assemblages with ostrich eggshell: Implications for palaeoecology and extirpation". Journal of Archaeological Science. 36 (9): 1982–1989. Bibcode:2009JArSc..36.1982J. doi:10.1016/j.jas.2009.05.012.
1 2 Andersson, Johan Gunnar (1923). On the occurrence of fossil remains of Struthionidae in China. In: Essays on the cenozoic of northern China. Memoirs of the Geological Survey of China (Peking), Series A, No. 3, pp. 53–77. Peking, China: Geological Survey of China.
↑ Wang, S. (2008). "Rediscussion in the taxonomic assignment of Struthio linxiaensis Hou, et al., 2005". Acta Paleotologica Sinica. 47: 362–368.
↑ Zelenkov, N. V.; Lavrov, A. V.; Startsev, D. B.; Vislobokova, I. A.; Lopatin, A. V. (2019). "A giant early Pleistocene bird from eastern Europe: unexpected component of terrestrial faunas at the time of early Homo arrival". Journal of Vertebrate Paleontology. 39 (2): e1605521. Bibcode:2019JVPal..39E5521Z. doi:10.1080/02724634.2019.1605521. S2CID198384367.
↑ Andersson, Johan Gunnar (1943). "Research into the prehistory of the Chinese". Bulletin of the Museum of Far Eastern Antiquities. 15: 1–300.
General references
Andersson, Johan Gunnar (1943). "Researches into the prehistory of the Chinese". Bulletin of the Museum of Far Eastern Antiquities. 15: 1–300, plus 200 plates.
Brands, Sheila (14 Aug 2008). "Taxon: Genus Struthio". Project: The Taxonomicon. Retrieved 12 Jun 2012.
Davies, S. J. J. F. (2003). "Ostriches". In Hutchins, Michael (ed.). Birds I Tinamous and Ratites to Hoatzins. Grzimek's Animal Life Encyclopedia. Vol.8 (2nded.). Farmington Hills, MI: Gale Group. p.99. ISBN978-0-7876-5784-0.
Janz, Lisa; etal. (2009). "Dating North Asian surface assemblages with ostrich eggshell: Implications for palaeoecology and extirpation". Journal of Archaeological Science. 36 (9): 1982–1989. Bibcode:2009JArSc..36.1982J. doi:10.1016/j.jas.2009.05.012.
The common ostrich, or simply ostrich, is a species of flightless bird native to certain large areas of Africa. It is one of two extant species of ostriches, the only living members of the genus Struthio in the ratite order of birds. The other is the Somali ostrich, which was recognized as a distinct species by BirdLife International in 2014 having been previously considered a distinctive subspecies of ostrich.
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, including a variety of flightless forms like the Paleotididae, Geranoididae, Eogruidae and Ergilornithidae, the latter two thought to be closely related to Struthionidae.
Ratites are a polyphyletic group consisting of all birds within the infraclass Palaeognathae that lack keels and cannot fly. They are mostly large, long-necked, and long-legged, the exception being the kiwi, which is also the only nocturnal extant ratite.
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 several species known from Holocene fossils such as the Asian ostrich. The common ostrich is the more widespread of the two living species, and is the largest living bird species. The extinct genus Pachystruthio from the Late Pliocene-Early Pleistocene of Eurasia is one of the largest birds ever.
Elephant birds are extinct flightless birds belonging to the order Aepyornithiformes that were native to the island of Madagascar. They are thought to have become extinct around 1000 AD, likely as a result of human activity. Elephant birds comprised three species, one in the genus Mullerornis, and two in Aepyornis.Aepyornis maximus is possibly the largest bird to have ever lived, with their eggs being the largest known for any amniote. Elephant birds are palaeognaths, and their closest living relatives are kiwi, suggesting that ratites did not diversify by vicariance during the breakup of Gondwana but instead convergently evolved flightlessness from ancestors that dispersed more recently by flying.
Anas is a genus of dabbling ducks. It includes the pintails, most teals, and the mallard and its close relatives. It formerly included additional species but following the publication of a molecular phylogenetic study in 2009 the genus was split into four separate genera. The genus now contains 31 living species. The name Anas is the Latin for "duck".
Flightless birds have, through evolution, lost the ability to fly. There are over 60 extant species, including the well-known ratites and penguins. The smallest flightless bird is the Inaccessible Island rail. The largest flightless bird, which is also the largest living bird in general, is the common ostrich.
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 infraclasses of birds, the other being Neognathae, both of which form Neornithes. Palaeognathae contains five extant branches of flightless lineages, termed ratites, and one flying lineage, the Neotropic tinamous. There are 47 species of tinamous, five of kiwis (Apteryx), three of cassowaries (Casuarius), one of emus (Dromaius), two of rheas (Rhea) and two of ostriches (Struthio). Recent research has indicated that paleognaths are monophyletic but the traditional taxonomic split between flightless and flighted forms is incorrect; tinamous are within the ratite radiation, meaning flightlessness arose independently multiple times via parallel evolution.
The Arabian ostrich, 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.
Palaeotis is a genus of paleognath birds from the middle Eocene epoch of central Europe. One species is known, Palaeotis weigelti. The holotype specimen is a fossil tarsometatarsus and phalanx. Lambrect (1928) described it as an extinct bustard, and gave it its consequent name. After a suggestion by Storrs L. Olson, a review of the type specimen and the referral of several other fossils by Houde and Haubold (1987) concluded that Palaeotis is a palaeognath and assigned it to the same order as ostriches; the Struthioniformes. In 2021, it was considered a member of the family Paleotididae alongside Galligeranoides from the Early Eocene of France, which were found to be basal members of the Struthioniformes.
The Somali ostrich, 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 previously considered a subspecies of the common ostrich, but was identified as a distinct species in 2014.
The Asian or Asiatic ostrich, is an extinct species of ostrich that lived during the Neogene period on the Indian subcontinent.
Bird ichnology is the study of avian life traces in ornithology and paleontology. Such life traces can include footprints, nests, feces and coproliths. Scientists gain insight about the behavior and diversity of birds by studying such evidence.
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, and China. The genus contains three species: P. pannonicus, P. dmanisensis, and P. transcaucasicus, which were all formerly placed with the ostrich genus, Struthio. An incomplete femur from the Nihewan Formation (China) has been assigned to Pachystruthio indet. P. dmanisensis has been estimated standing 3.5 meters tall and weighing up to 450 kg (990 lb), making it much larger than the modern ostrich and one of the largest known birds.
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.
Orientornis is an extinct species of ratite from the Miocene of China.
The North African ostrich, red-necked ostrich, or Barbary ostrich is the nominate subspecies of the common ostrich from West and North Africa. It has the largest average size among the subspecies of ostriches, making it the largest living bird.
Incognitoolithus is an oogenus of medioolithid fossil bird egg. It is notable for bearing evidence of predation, possibly from a bird pecking the eggshell.
Geranoididae is a clade of extinct birds from the early to late Eocene and possibly early Oligocene of North America and Europe. These were mid-sized, long-legged flightless birds. Recent research shows that these birds may actually be palaeognaths related to ostriches.
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