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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

Status: Endangered


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

IUCN Status:

Countries Where the Arabian Oryx Is Currently Found:

2003: Occurs in re-introduced populations in BahrainIsrael, 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

Weight:

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)

Gestation Period:

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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By: Paul Massicot; Last modified: February 13, 2007; © 1999 - 2007 Animal Info