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Animal Info - Arabian Oryx
(Other Names:
阿拉伯剑羚, 阿拉伯羚,
阿拉伯大羚羊, アラビアオリックス, Orix de Arabia,
Oryx d'Arabie, Oryx Blanc, Oryx Branco, Weiße Oryx, White Oryx)
Oryx leucoryx
Contents
1. Profile (Picture)
2. Tidbits
3. Status and Trends (IUCN Status, Countries Where
Currently Found, Population Estimates, History of Distribution, Threats and Reasons
for Decline)
4. Data on Biology and Ecology (Weight, Habitat, Age to Maturity, Gestation
Period, Birth Season, Birth Rate, Early Development, Maximum Age, Diet, Behavior, Social
Organization, Minimum Viable Population, Genetics)
5. References
Profile
Pictures: Arabian Oryx #1
(30 Kb JPEG); Arabian Oryx #2
(Huffman 2004)
The Arabian oryx is a medium-sized antelope weighing 65 - 75 kg (140 - 170 lb). Prior
to its extinction in the wild, it is believed to have occurred in flat and undulating
gravel plains intersected by shallow wadis and
depressions, and the dunes edging sand deserts, with a diverse vegetation of trees,
shrubs, herbs, and grasses. The Arabian oryx eats mainly grasses.
Herbs, seedpods, fruit,
fresh growth of trees, tubers and roots also form part of its diet. It can go for weeks
without drinking water. The Arabian oryx apparently digs shallow depressions in soft
ground under trees and shrubs for resting.
The Arabian oryx lives in nomadic herds that follow the rare rains, and it is able to
utilize effectively the fresh plant growth that occurs after a rainfall. The normal group
size is 8 - 20 animals, but herds of up to 100 have been reported. A herd contains all
ages and both sexes. Such herds probably stay together for a considerable time. Oryx are
very compatible with one another - the low frequency of aggressive interactions allows
animals to share scattered shade trees under which they may spend 8 of the daylight hours
in the summer heat.
Around 1800 the Arabian oryx was thought to have occurred over most of the Arabian
Peninsula (which includes modern Israel, Jordan, Syria, Iraq, portions of Egypt
(Sinai Peninsula), Saudi Arabia, Oman, Yemen, United Arab Emirates, Bahrain, Kuwait
and Qatar). By 1970 it was found only in the southeastern regions of the Rub' al Khali
desert on the Arabian
Peninsula. The last one in the wild was shot in 1972. Animals raised in captive
populations were re-introduced into the wild in Oman
in 1982. Additional
re-introduced populations now occur in Bahrain,
Israel and Saudi
Arabia, with a total reintroduced population in the wild of approximately 886
in 2003.
The main cause of the extinction of the Arabian oryx in the wild was overhunting, both
hunting by Bedouin for meat and hides as well as sport hunting by motorized parties.
Poaching of re-introduced wild Arabian oryx has become a serious threat again. At least
200 oryx were taken or killed by poachers from the re-introduced wild Omani herd in three
years after poaching began there in February 1996.
Tidbits
*** The Arabian oryx is one of the world's rarest mammals.
*** "Even when modern rifles came into general use the species [of the Arabian
desert] held their own in the vast spaces to a very satisfactory extent. But the last
decade has witnessed the advent of a shocking predator, namely the 'Mighty Jeep'. It
cannot be long now before motorized hunting parties will sweep Arabia's fauna into
uttermost corners, where a subsequent drought will whiten its bones." (Foster-Vesey-Fitzgerald 1952)
*** "The last wild Arabian oryx was shot in 1972, leaving a few in private
collections in Arabia and the World Herd in the USA.
This herd grew out of the 1962 Operation Oryx, organized by the far-sighted Fauna and
Flora Preservation Society [now Fauna and Flora International] to ensure the survival of
the species in captivity. By 1982, ecological and social conditions in Oman were deemed right for the release of a carefully
developed herd, with the long-term aim of re-establishing a viable population." (Macdonald 1984)
*** The Arabian oryx is able to detect rainfall over great distances and moves towards
it to take advantage of the vegetation that springs up after a rain. The rainfall is
irregular, and the oryx must travel over an area of hundreds of sq km (a hundred sq mi) to
obtain adequate food.
Status and Trends
Countries Where the Arabian Oryx Is Currently Found:
2003: Occurs in re-introduced populations in Bahrain, Israel, Oman,
and Saudi Arabia. (IUCN
2004)
Population Estimates:
[Note: Figures given are for wild populations only.]
History of Distribution:
Around 1800 the Arabian oryx was thought to have occurred over most of the Arabian
Peninsula (which includes modern Israel, Jordan, Syria, Iraq, portions of Egypt
(Sinai Peninsula), Saudi Arabia, Oman, Yemen, United Arab Emirates, Bahrain, Kuwait
and Qatar). By 1970 it was found only in the southeastern regions of the Rub' al Khali
desert on the Arabian
Peninsula. The last one in the wild was shot in 1972.
Animals raised in captive populations were re-introduced into the wild in Oman in 1982. This herd did well, increasing to over 400
animals by 1996. At that point poachers began taking oryx from this herd, and the
herd decreased to 106 (100 males, 6 females) by 2003. Additional
re-introduced populations occur in Bahrain,
Israel and Saudi
Arabia, with a total reintroduced population in the wild of approximately 886
in 2003 (IUCN
2004).
Threats and Reasons for Decline:
The main cause of the extinction of the Arabian oryx in the wild was overhunting, both
hunting by Bedouin for meat and hides as well as sport hunting by motorized parties.
The Oman population has been devastated by illegal live capture for sale to
private collections and this remains the main threat. The security of animals
that wander outside the protected areas where they have been released cannot be
guaranteed. Drought and overgrazing have reduced habitat quality in places and
limited the choice of potential release further release sites. (IUCN
2004)
Data on Biology and Ecology
The Arabian oryx weighs 100 - 210 kg (220 - 460 lb).
Habitat:
The Arabian oryx is believed to have occurred in flat and undulating gravel plains
intersected by shallow wadis and depressions, and the
dunes edging sand deserts, with a diverse vegetation of trees, shrubs, herbs, and grasses.
The Arabian oryx occurs in the Arabian Fog Woodlands & Shrublands Global 200
Ecoregion. (Olson & Dinerstein
1998, Olson & Dinerstein 1999)
Age to Maturity:
The first birth is usually between the ages of 25 and 46 months. Thus, under good
conditions, 2-year old females should give birth. (Saltz 1998)
9 months.
Birth Season:
Births can occur in any month.
Birth Rate:
Under favorable conditions a female can produce a calf once a year.
"Data on age-related reproductive success in Arabian oryx are limited. I found no
data on age-related reproductive success in adult females... Births take place every 9.5 -
13.3 months. Thus, I assumed 1 year between births under good conditions, or, in other
words, a reproductive rate of 1.0 calves/female/year. If male:female birth ratio is 1:1,
then one obtains 0.5 female calves/adult female/year." (Saltz 1998)
Early Development:
A young oryx is usually weaned by the time it is 4.5 months old.
Maximum Age:
Probably about 20 years.
Diet:
The Arabian oryx eats mainly grasses. Herbs, seedpods, fruit, fresh growth of trees,
tubers and roots also form part of its diet. It can go for weeks without drinking water.
A metabolic analysis concluded that adult Arabian oryx consume 1.35 kg/day
(3.0 lb/day) of dry matter (494 kg/year) (1090 lb/year) (Treydte
et al. 2001).
Behavior:
The Arabian oryx has several adaptations that enable it to remain
independent of water sources during the summer by fulfilling its water needs
from its forage. For example, it spends the hot part of the day lying
completely inactive under shade trees, conducting body heat into the ground to
reduce water loss from evaporation; and it forages at night, selecting
water-rich food species. (van
Heezik et al. 2003)
Social Organization:
The Arabian oryx lives in nomadic herds that follow the rare rains, and it is able to
utilize effectively the fresh plant growth that occurs after a rainfall. The normal group
size is 8 - 20 animals, but herds of up to 100 have been reported. A herd contains all
ages and both sexes. Such herds probably stay together for a considerable time. Oryx are
very compatible with one another - the low frequency of aggressive interactions allows
animals to share scattered shade trees under which they may spend 8 of the daylight hours
in the summer heat.
Minimum Viable Population:
"...there were insufficient data to carry out a detailed viability analysis for
the Arabian oryx..." (Saltz 1998)
Genetics:
Genetic analyses of the re-introduced Omani population of Arabian oryx in 1995
confirmed that the re-introduced population did not carry all of the genetic variation of
the aboriginal population. However, no association between inbreeding coefficients and
fitness components were found, although there were associations between measures of
microsatellite DNA variation and juvenile survival indicating both inbreeding and
outbreeding depression. The high rate of intrinsic growth of the Omani population
suggested that simultaneous inbreeding and outbreeding were not major threats to
population viability. (Spalton et al. 1999)
Genetic data revealed that low but significant population differentiation
was found between most Arabian oryx groups, suggesting that management of
Arabian oryx has led to substantial genetic mixing between populations. (Marshal
et al. 1999)
References
Arab. Oryx Proj. 2003,
Arabian oryx.com, AZA 1998, AZA
Antelope TAG, Burton
& Pearson 1987, Curry-Lindahl 1972, Fossil Rim Wildlife Center, Foster-Vesey-Fitzgerald 1952, Harrison 1968, Huffman
2004, IUCN 1969, IUCN
1994, IUCN 1996, IUCN
2000, IUCN 2003a,
IUCN 2004,
Macdonald 1984, Marshal
et al. 1999, Nowak & Paradiso 1983, Olson & Dinerstein 1998, Olson & Dinerstein 1999, Oryx 1982d, Oryx
1993a, Oryx 1994, Oryx 1997f, Ostrowski et al. 1998, Saltz 1998, Seddon
et al. 2003, Spalton
et al. 1999, Treydte et al. 2001,
van Heezik et al. 2003, WCMC/WWF 1997
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