Ostrich
Ostriches are large flightless birds. Two living species
are recognised; the common ostrich, native to large parts of Sub-Saharan Africa, and
the Somali ostrich, native to the Horn of
Africa.
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 70 km/h (43.5 mph),[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.
Ostriches are 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, cassowaries, kiwi and
the extinct elephant birds and moa.
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.
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.
Distribution and habitat
