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Animal Info - Scimitar-horned Oryx
(Other Names: 弯角剑羚,
弯角大羚羊, 彎角羚,
シロオリックス, Algazelle,
Antilope Oryx, Begar al Ouach, Orix de Cimitarra, Oryx Algazelle, Oryx Blanc, Oryx de Libye, Sahara
Oryx, Säbelantilope, Scimitar Oryx, Wach)
Oryx dammah (O. tao)
Status: Extinct
in the Wild
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, Maximum Age, Diet, Behavior,
Social Organization, Density and Range, Mortality and Survival)
5. References
Profile
Pictures: Scimitar-horned
Oryx #1 (Huffman 2004);
Scimitar-horned
Oryx #2 (62 Kb JPEG) (AZA
Antelope TAG)
The scimitar-horned oryx, named for its scimitar-shaped horns, weighs up to 220 kg (480 lb).
The scimitar-horned oryx inhabits the sub-desert lands - the transition zones between true desert
(Sahara) and the Sahel, with a rainfall of between 75 and 150 mm (3 - 6"). It is found in rolling dunes, grassy steppes and wooded inter-dunal
depressions. It very rarely penetrates either true desert or true Sahel
country. The scimitar-horned oryx selectively feeds on a variety of foods - primarily grasses, but also
legumes and leaves and the fruit of trees and shrubs. It is well adapted to arid lands, being able to
go for 9 - 10 months without drinking water by utilizing the moisture in the vegetation it
eats.
The scimitar-horned oryx is a gregarious, living in
groups with a wide range of sizes. In the past, at certain times of the
year, in areas of fresh pasture or surface water after rainfall, or during the wet season
migrations, herds numbered up to 1000 or more. Herds of scimitar-horned
oryx migrated north into the Sahara during the wet season and returned south at the
beginning of the dry season.
The scimitar-horned oryx was formerly distributed from Mauritania in
the west to the Red Sea in the east, but it declined drastically, apparently to
extinction in the wild. Overhunting
is the major cause of the decline, especially after motorized hunting with modern firearms
began. Hunting has been carried out by nomads, oil surveyors, and military personnel, for
meat, hides and sport. In addition, its habitat became increasingly drier and less
suitable, due to long-term climate change as well as to overgrazing by livestock and man's
destruction of tree cover. Furthermore, the increasing presence of livestock
drove
the oryx away from the pastures where it formerly obtained both food and water.
Tidbits
*** In the early 1970's, the scimitar-horned oryx, together with the addax,
were considered the most endangered of the African antelopes (Curry-Lindahl 1972). The scimitar-horned oryx
has proved to be even more vulnerable to human
disturbance than the addax, because of its inability to penetrate
the harsh desert except when scarce rain has fallen to promote plant growth.
*** The scimitar-horned oryx has a number of physiological adaptations to conserve body
water that help it survive in its desert habitat. For example, its kidneys are very
efficient at minimizing the loss of water in urine, and it sweats only when its body temperature exceeds 46 deg C (116 deg F).
*** In 1986, a breeding herd of 10 juvenile scimitar-horned oryx (5 males and
5 females), were released into the Bou Hedma National Park in Tunisia.
These oryx reproduced successfully and by 1997, the first ten oryx had produced
a herd of 84 animals. (Intl.
Found. Cons. Wildl. 2004)
Status and Trends
- 1960's - 1970's: Vulnerable
- 1980's - 1994:
Endangered
- 1996: Critically
Endangered (Criteria: A1c, C1+2a)
- 2000 - 2004: Extinct in the Wild (IUCN
2004)
Countries Where the Scimitar-horned Oryx Is Currently Found:
2004: Occurs in Israel (introduced populations)
and Tunisia (re-introduced populations).
May occur in Niger. (IUCN
2004)
Population Estimates:
[Note: Figures given are for wild populations only.]
History of Distribution:
During the Middle Ages the scimitar-horned oryx was probably the most numerous
large mammal
of the semideserts just south of the Sahara. It was distributed from Mauritania in the west to the Red Sea in the
east, along the
interface between true desert and less arid Sahelian or Mediterranean habitats
under an annual rainfall of between 75 and 150 mm (3 - 6").
Even as late as the 1920's and 30's it was considered common over much of its range from
the Atlantic to the Nile. By the 1950's its range was fragmented, although substantial
numbers survived in some areas. By the late 1970's it only survived in scattered populations. By
the mid-1980's it was said to be on the brink of extinction. By 2000, it was thought to be extinct in the wild, although there was a recent
unsubstantiated sighting of four animals in northern Niger
(IUCN 2004).
A summary chronology of extinctions of the scimitar-horned oryx in the wild:
Tunisia (1910), Morocco (1973), Egypt (1975), Algeria (1987), Mali (1990), Niger
(1990), Sudan (?), Libya (?), Chad (2000) (Mallon & Kingswood
2001, IUCN 2004)
Distribution Map
(15 Kb GIF) (African Mammals
Databank 2004)
Threats and Reasons for Decline:
The original decline of the scimitar-horned oryx started with climatic changes that led to the
drying out of the Sahara. As the desert expanded to north and to south, the
scimitar-horned oryx was pushed
northward and southward, and desertification divided it into two isolated populations. The
northern group probably was never as common as the southern group.
The decline of the southern group worsened beginning with the arrival of Europeans in
western and westcentral Africa in the latter part of the 19th century and the installation
of numerous military posts in the arid regions. As firearms and horses increased, and then
motorized vehicles were introduced, hunting began to take a major toll. The hunting was carried out by
nomads for meat and hides for domestic consumption and trade, and by oil surveyors and
troops. Not only were animals shot from motorized vehicles, sometimes with automatic
weapons, but many of the slow-running desert animals died of heat exhaustion, calves were
abandoned in the chase and unborn young aborted. During World War II, military operations probably led
to considerable additional hunting to feed the armies. Finally, the civil war which began
in Chad in the 1960's had a serious effect.
In addition to the major impact of overhunting, the increasing presence of livestock,
stimulated by deep wells for watering cattle on the edge of the Sahel, drove the oryx away from the pastures where it
formerly obtained both food and water.
Data on Biology and Ecology
The scimitar-horned oryx weighs up to 220 kg (480 lb).
Habitat:
The scimitar-horned oryx inhabits the sub-desert lands - the transition zones between true
desert (Sahara) and the Sahel, with a rainfall of between 75 and 150 mm (3 - 6"). It is found in rolling dunes, grassy steppes and wooded
inter-dunal depressions. It very rarely penetrates either true desert or true Sahel
country (Newby 1980).
The scimitar-horned oryx occurs in the Mediterranean
Basin Biodiversity
Hotspot (Cons.
Intl.).
Age to Maturity:
Young are sexually mature by 2 years of age (Burnie
& Wilson 2001).
8 - 8.5 months.
Birth Season:
Births may occur throughout the year but with peaks occurring during
the late cold/early hot season (February - April) and the late rainy/early cold season
(September - November) (East
1990).
Birth Rate:
A female scimitar-horned oryx has 1 young per birth.
Early Development:
The mother leaves the herd to calve but returns within hours. Young
are weaned by 14 weeks (Burnie
& Wilson 2001).
Maximum Age:
Captive animals have lived for 17 years (Kingdon
1997).
Diet:
The scimitar-horned oryx selectively feeds on a variety of foods - primarily grasses, but also
legumes and leaves and the fruit of trees and shrubs (Mallon & Kingswood
2001).
Like many arid-area adapted mammals, scimitar-horned oryx are able
to survive without drinking water for 9 - 10 mouths, drawing sufficient moisture from their
plant food (Newby 1980).
Behavior:
In the Sahelian range of the scimitar-horned oryx, seasonal migrations
over significant distances, up to several hundred km (1-200 miles), have been recorded. During
the hot season, from March to May, the oryx are found in the southern part of
their range. At the beginning of the rains, that appear in the south of the Sahel
at the end of May or the beginning of June, they move further south, to
the sub-Sahelian wooded steppes. At the end of June or in July, they perform
rapid, massive migrations towards the north of their range, where the rains
have started, taking advantage of the pastures to the extent that competition
with domestic herds permits. In August they reach the northernmost latitudes,
between 16 and 17 deg N latitude. In October and November, the larger herds
disperse for the cold season. They return in March towards the summer
quarters. This cycle varies as a function of variations in the annual
rainfall. (Beudels-Jamar et al.
1998)
The scimitar-horned oryx is primarily crepuscular,
although it also feeds during moonlit nights. During the day it rests in the
shade if available. (Mallon & Kingswood
2001)
Social Organization:
Scimitar-horned oryx are gregarious.
They are found in herds whose size constantly changes, depending on the size
of the patches of vegetation they are feeding on. New herds collect and
disperse as ephemeral vegetation comes and goes in response to irregular
rainfall. In the past the groups could be quite large - a single herd of 10,000 oryx was sighted in 1936.
As oryx populations shrank, so did the herd size.
Density and Range:
One estimate of typical density suggested one scimitar-horned oryx for
every 40 sq km (15 sq mi) of desert habitat (Kingdon
1997).
Mortality and Survival:
Observations in Chad showed that the scimitar-horned oryx had an annual birth rate of
approximately 12 - 15% of the total population, and the number of surviving
juveniles may have been as high as 10 - 14% annually (Newby
1980).
References
African Mammals Databank
2004,
Arkive,
AZA 1994a, AZA
Antelope TAG, Bassett
1975, Beudels-Jamar et al.
1998, Burnie & Wilson 2001,
Burton & Pearson 1987, Cons.
Intl., Curry-Lindahl 1972, East
1990, Fossil
Rim Wildlife Center, Huffman
1999f, Intl. Found.
Cons. Wildl. 2004, Huffman 2004, IUCN 1969, IUCN 1994,
IUCN 1996, IUCN 2000,
IUCN 2003a, IUCN
2004, Kingdon 1997, Macdonald 1984,
Mallon & Kingswood 2001, Newby 1978, Newby
1980, Nowak & Paradiso 1983, Oryx 1970, Oryx
1982c, Oryx 1984, Oryx 1986g, Oryx
1987, Oryx 1989e, Stuart & Stuart 1996
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