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Ostrich

2007 Schools Wikipedia Selection. Related subjects: Birds

                     iOstrich

                             Conservation status

   Least Concern (LC)
            Scientific classification

   Kingdom: Animalia
   Phylum:  Chordata
   Class:   Aves
   Order:   Struthioniformes
   Family:  Struthionidae
            Vigors, 1825
   Genus:   Struthio
   Species: S. camelus

                                Binomial name

   Struthio camelus
   Linnaeus, 1758

   The ostrich (Struthio camelus) is a flightless bird native to Africa.
   It is the only living species of its family, Struthionidae, and its
   genus, Struthio. They are distinct in their appearance, with a long
   neck and legs and the ability to run at speeds of about 65 km/h (40
   mph). Ostriches are the largest living species of bird and are farmed
   in many areas all over the world. The scientific name for the ostrich
   is from the Greek for "camel sparrow" in allusion to their long necks.

Description

   Ostriches usually weigh from 90 to 130 kg (200 to 285 pounds), although
   some male ostriches have been recorded with weights of up to 155 kg
   (340 pounds). The feathers of adult males are mostly black, with some
   white on the wings and tail. Females and young males are grayish-brown,
   with a bit of white. The small vestigial wings are used by males in
   mating displays. They can also provide shade for chicks. The feathers
   are soft and serve as insulation, and are quite different from the
   stiff airfoil feathers of flying birds. There are claws on two of the
   wings' fingers. The strong legs of the ostrich lack feathers. The bird
   stands on two toes, with the bigger one resembling a hoof. This is an
   adaptation unique to ostriches that appears to aid in running.

   At sexual maturity (two to four years old), male ostriches can be
   between 1.8 m and 2.7 m (6 feet and 9 feet) in height, while female
   ostriches range from 1.7 m to 2 m (5.5 ft to 6.5 ft). During the first
   year of life, chicks grow about 25 cm (10 inches) per month. At one
   year, ostriches weigh around 45 kg (100 pounds). An ostrich can live up
   to 75 years.

Systematics and distribution

   The ostrich belong to the Struthioniformes order ( ratites). Other
   members of this group include rheas, emus, cassowaries and the largest
   bird ever, the now-extinct Aepyornis. However, the classification of
   the ratites as a single order has always being questioned, with the
   alternative classification restricting the Struthioniformes to the
   ostrich lineage and elevating the other groups to order status also.
   Presently, molecular evidence is equivocal while paleobiogeographical
   and paleontological considerations are slightly in favour of the
   multi-order arrangement.
   The present-day distribution of ostriches.
   Enlarge
   The present-day distribution of ostriches.

   Ostriches occur naturally in the savannas and the Sahel of Africa, both
   north and south of the equatorial forest zone. Five subspecies are
   recognized:
     * S. c. australis in Southern Africa
     * S. c. camelus in North Africa, sometimes called the North African
       ostrich or red-necked ostrich.
     * S. c. massaicus in East Africa, sometimes called the Masai ostrich.
       During the mating season, the male's neck and thighs turn
       pink-orange. Their range is from Ethiopia and Kenya in the east to
       Senegal in the west, and from eastern Mauritania in the north to
       southern Morocco in the south.
     * S. c. syriacus in the Middle East, sometimes called the Arabian
       ostrich or Middle Eastern ostrich, was a subspecies formerly very
       common in the Arabian Peninsula, Syria, and Iraq; it became extinct
       around 1966.
     * S. c. molybdophanes in Somalia, Ethiopia, and northern Kenya, is
       called the Somali ostrich. During the mating season, the male's
       neck and thighs turn blue. Its range overlaps with S.c. massaicus
       in northeastern Kenya.

   Analyses indicate that the Somali ostrich may be better considered a
   full species. mtDNA haplotype comparisons suggest that it diverged from
   the other ostriches not quite 4 mya due to formation of the Great Rift
   Valley. Subsequently, hybridization with the subspecies that evolved
   southwestwards of its range, S. c. massaicus, has apparently been
   prevented to occur on a significant scale by ecological separation, the
   Somali ostrich preferring 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
   (Freitag & Robinson, 1993).

   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, but as there is considerable variation of this character and
   there were no other differences between these birds and adjacent
   populations of S. c. camelus, it is not anymore considered valid. This
   population has disappeared in the later half of the 20th century. In
   addition, there have been 19th century reports of the existence of
   small ostriches in North Africa; these have been referred to as
   Levaillant's Ostrich (Struthio bidactylus) but remain a hypothetical
   form not supported by material evidence (Fuller, 2000). Given the
   persistence of savanna wildlife in a few mountaineous regions of the
   Sahara (such as the Tagant Plateau and the Ennedi Plateau), it is not
   at all unlikely that ostriches too were able to persist in some numbers
   until recent times after the drying-up of the Sahara.

Evolution

   Ostrich, Melbourne Zoo
   Enlarge
   Ostrich, Melbourne Zoo

   The earliest fossil of ostrich-like birds is the Central European
   Palaeotis from the Middle Eocene, a middle-sized flightless bird that
   was originally believed to be a bustard. Its distribution indicates
   that its ancestors must have flown across the ocean which at that time
   separated the continents from each other, and this indicates that
   theories about evolution and dispersal of the ratites need much more
   research before a consensus can be reached. Apart from this enigmatic
   bird, the fossil record of the ostriches continues with several species
   of the modern genus Struthio which are known from the Early Miocene
   onwards. While the relationship of the African species is comparatively
   straightforward, a large number of Asian species of ostrich have been
   described from very fragmentary remains, and their interrelationships
   and how they relate to the African ostriches is very confusing. In
   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
   there on prehistoric pottery and as petroglyphs. There are also records
   in maritime history of ostriches being sighted way out at sea in the
   Indian Ocean and when discovered on the island of Madagascar the
   sailors of the 18th century referred to them as Sea Ostriches, although
   this has never been confirmed.

   Several of these fossil forms are ichnotaxa and their association with
   those described from distinctive bones is contentious and in need of
   revision pending more good material (Bibi et al., 2006).
     * Struthio coppensi (Early Miocene of Elizabethfeld, Namibia)
     * Struthio linxiaensis (Liushu Late Miocene of Yangwapuzijifang,
       China)
     * Struthio orlovi (Late Miocene of Moldavia)
     * Struthio karingarabensis (Late Miocene - Early Pliocene of SW and
       CE Africa) - oospecies(?)
     * Struthio kakesiensis (Laetolil Early Pliocene of Laetoli, Tanzania)
       - oospecies
     * Struthio wimani (Early Pliocene of China and Mongolia)
     * Struthio daberasensis (Early - Middle Pliocene of Namibia) -
       oospecies
     * Struthio brachydactylus (Pliocene of Ukraine)
     * Struthio chersonensis (Pliocene of SE Europe to WC Asia) -
       oospecies
     * Asian Ostrich, Struthio asiaticus (Early Pliocene - Late
       Pleistocene of Central Asia to China)
     * Struthio oldawayi (Early Pleistocene of Tanzania) - probably
       subspecies of S. camelus
     * Struthio anderssoni - oospecies(?)

Behaviour

   Ostriches live in nomadic groups of 5 to 50 birds that often travel
   together with other grazing animals, such as zebras or antelopes. They
   mainly feed on seeds and other plant matter; occasionally they also eat
   insects such as locusts. Lacking teeth, they swallow pebbles that help
   as gastroliths to grind the swallowed foodstuff in the gizzard. An
   adult ostrich typically carries about 1 kg of stones in its stomach.
   Ostriches can go without water for a long time, exclusively living off
   the moisture in the ingested plants. However, they enjoy water and
   frequently take baths.

   With their acute eyesight and hearing, they can sense predators such as
   lions from far away.

   In popular mythology, the ostrich is famous for hiding its head in the
   sand at the first sign of danger. The Roman writer Pliny the Elder is
   noted for his descriptions of the ostrich in his Naturalis Historia,
   where he describes the ostrich and the fact that it hides its head in a
   bush. There have been no recorded observations of this behavior. A
   common counter-argument is that a species that displayed this behaviour
   would not likely survive very long. The myth may have resulted from the
   fact that, from a distance, when ostriches feed they appear to be
   burying their head in the sand because they deliberately swallow sand
   and pebbles to help grind up their food. Burying their heads in sand
   will in fact suffocate the ostrich. When lying down and hiding from
   predators, the birds are known to lay their head and neck flat on the
   ground, making them appear as a mound of earth from a distance. This
   even works for the males, as they hold their wings and tail low so that
   the heat haze of the hot, dry air that often occurs in their habitat
   aids in making them appear as a nondescript dark lump. When threatened,
   ostriches run away, but they can also seriously injure with kicks from
   their powerful legs.

   The ostrich's behaviour is also mentioned in what is thought to be the
   most ancient book of the Bible in God's discourse to Job ( Job
   39.13-18). It is described as joyfully proud of its small wings,
   unmindful of the safety of its nest, treats its offspring harshly,
   lacks in wisdom, yet can put a horse to shame with its speed.
   Elsewhere, ostriches are mentioned as proverbial examples of bad
   parenting (see Arabian Ostrich for details).

   Ostriches are known to eat almost anything ( dietary indiscretion),
   particularly in captivity where opportunity is increased.

   Ostriches can tolerate a wide range of temperatures. In much of its
   habitat temperature differences of 40°C between night- and daytime can
   be encountered. Their temperature control mechanism is more complex
   than in other birds and mammals, utilizing the naked skin of the upper
   legs and flanks (see the photo of the "dancing" female ostrich below)
   which can be covered by the wing feathers or bared according to whether
   the bird wants to retain or lose body heat.

Reproduction

   An ostrich's nest
   Enlarge
   An ostrich's nest

   Ostriches become sexually mature when 2 to 4 years old; females mature
   about six months earlier than males. The species is iteroparous, with
   the mating season beginning in March or April and ending sometime
   before September. The mating process differs in different geographical
   regions. Territorial males will typically use hisses and other sounds
   to fight for a harem of 2 to 5 females (which are called hens). The
   winner of these fights will breed with all the females in an area but
   only form a pair bond with one, the dominant female. The female
   crouches on the ground and is mounted from behind by the male.

   Ostriches are oviparous. The females will lay their fertilized eggs in
   a single communal nest, a simple pit scraped in the ground and 30 to 60
   cm deep. Ostrich eggs can weigh 1.3 kg and are the largest of all eggs,
   though they are actually the smallest eggs relative to the size of the
   bird. The nest may contain 15 to 60 eggs, with an average egg being 6
   inches (15 cm) long, 5 inches (13 cm) wide, and weigh 3 pounds (1.4
   kg). They are shiny and whitish in colour. The eggs are incubated by
   the females by day and by the male by night, making use of the
   different colors of the two sexes to escape detection. The gestation
   period is 35 to 45 days. Typically, the male will tend to the
   hatchlings.

   The life span of an ostrich can extend from 30 to 70 years, with 50
   being typical.

Ostriches and humans

   In the past, ostriches were mostly hunted and farmed for their
   feathers, which used to be very popular as ornaments in ladies' hats
   and such. Their skins were also valued to make a fine leather. In the
   18th century, they were almost hunted to extinction; farming for
   feathers began in the 19th century. The market for feathers collapsed
   after World War I, but commercial farming for feathers and later for
   skins, took off during the 1970s.

   The Arabian Ostriches in the Near and Middle East were hunted to
   extinction by the middle of the 20th century.

   Today, ostriches are bred all over the world, including climates as
   cold as that of Sweden. They will prosper in climates between 30 and
   −30 °C, and are farmed in over 50 countries around the world, but the
   majority are still found in Southern Africa. Since they also have the
   best feed to weight ratio gain of any land animal in the world (3.5:1
   whereas that of cattle is 6:1), they are bound to appear attractive to
   farmers. Although they are farmed primarily for leather and secondarily
   for meat, additional useful byproducts are the eggs, offal, and
   feathers. It is traditional to place seven of the large eggs on the
   roof of an Ethiopian Orthodox church, to symbolise the Heavenly and
   Earthly Angels.

   It is claimed that ostriches produce the strongest commercially
   available leather^1. Ostrich meat tastes similar to lean beef and is
   low in fat and cholesterol, as well as high in calcium, protein and
   iron.

   Ostriches are large enough for a small human to ride them; typically,
   the human will hold on to the wings while riding. They have been
   trained in some areas of northern Africa and Arabia as racing mounts.
   Ostrich races in the United States have been criticized by animal
   rights organizations, however there is little possibility of this
   becoming a widespread practice due to the fact that the animals are
   difficult to saddle (and ostriches are known to have a rather irascible
   temper).

   Ostriches are classified as dangerous animals in Australia, the US and
   the UK. There are a number of recorded incidents of people being
   attacked and killed. Big males can be very territorial and aggressive
   and can attack and kick very powerfully with their legs. An ostrich
   will easily outrun any human athlete. Their legs are powerful enough to
   eviscerate large animals.

Ostrich farming

   The town of Oudtshoorn in South Africa has the world's largest
   population of ostriches. Many farms and specialized breeding centres
   have been set up around the town such as the Safari Show Farm and the
   Highgate Ostrich Show Farm. The CP Nel Museum is a museum that
   specializes in the history of the ostrich.

Gallery

   Head of an ostrich.

   An ostrich egg.

   Ostrich eggs for sale in a Polish supermarket.

   Male and female ostriches "dancing" by flapping their wings.

   Male and female ostriches on a farm in New Zealand.

   Ostrich farm between Phoenix and Tucson, Arizona.

   Ostriches in a zoo in Krasnoyarsk city ( Siberia).

   Thermographic image of two ostriches in wintertime.
   Retrieved from " http://en.wikipedia.org/wiki/Ostrich"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
