The East African oryxes have traditionally been treated as a single species, Oryx beisa (and often even considered conspecific with the Gemsbok, O. gazella, of southwestern Africa). According to Groves (2011), however, although they are very similar in appearance they are best treated as three distinct species: Beisa Oryx (O. beisa), found in northern and central Somalia and the Ogaden region of Ethiopia north to Berbera, west to Eritrea, and south into the Awash Valley; Oryx (O. gallarum), found in northern Kenya and northeastern Uganda and extending into Somalia and southeastern Ethiopia; and Fringe-eared Oryx (O. callotis), found in southeastern Kenya and northeastern Tanzania.
The Beisa Oryx is a large antelope with a thick neck, long face, and long straight horns. It is found mainly in desert country, arid grassland, and scrub. It typically occurs in small herds of 7 to 30 individuals. It is reported to be common in the Awash National Park, but declining elsewhere due to hunting and overgrazing. Population declines likely approached 25% over the past three generations.
(Kingdon 1997; Groves 2011)
- Groves, C.P. 2011. Genus Oryx. Pp. 688-692 in: Wilson, D.E. and Mittermeier, R.A., eds. Handbook of the Mammals of the World. Volume 2. Hoofed Mammals. Lynx Edicions, Barcelona.
- Kingdon, J. 1997. The Kingdon Field Guide to African Mammals. Academic Press, San Diego.
There is no recent confirmation of Beisa Oryx occurrence in Eritrea, where its status is uncertain. Likewise, the failure to locate any oryx during a 1995 aerial survey of Bokora Corridor, Matheniko and adjoining areas of Karamoja suggests that it has either disappeared completely from Uganda or at best survives in very small numbers (East 1999).
Fringe-eared Oryx are distributed entirely south of the Tana River in eastern Kenya and north-east Tanzania, with a major centre of distribution in Tsavo (East) and the Galana Ranch region (Cobb 1976), spreading west and south to Mkomazi, Amboseli and sporadically appearing in Serengeti (Wacher and Kingdon in press).
Habitat and Ecology
Molecular Biology and Genetics
Barcode data: Oryx beisa
Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen.
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Statistics of barcoding coverage: Oryx beisa
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
IUCN Red List Assessment
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East (1999), correcting for undercounting bias, gives estimated total populations of about 50,000 Beisa Oryx and 17,000 Fringe-eared Oryx (East 1999). Population trends are probably gradually downward over most of the species’ current range, with exceptions in areas such as Sibiloi and Laikipia (Beisa Oryx) and Kajiado, Tarangire and Mkomazi (Fringe-eared).
About 60% of Fringe-eared Oryx are in protected areas, particularly in Tsavo, Kajiado and Kilifi (Kenya) and Tarangire and Mkomazi (Tanzania).
More effective protection and management of the remaining populations in areas where the species still occurs in substantial numbers but its populations are in decline, such as the Awash Valley, Omo-Mago-Chew Bahir, northern Kenya and Tsavo, would greatly enhance the long-term survival prospects of this species (East 1999).
Populations of Beisa Oryx are maintained in captivity.
East African oryx
The East African oryx (Oryx beisa), also known as the beisa is a species of antelope from East Africa. It has two subspecies: the common beisa oryx (Oryx beisa beisa) found in steppe and semidesert throughout the Horn of Africa and north of the Tana River, and the fringe-eared oryx (Oryx beisa callotis) south of the Tana River in southern Kenya and parts of Tanzania. In the past, some taxonomists considered it a subspecies of the gemsbok (Oryx gazella), but they are genetically distinct; the diploid chromosome count is 56 for the beisa and 58 for the gemsbok.
The East African oryx stands just over a metre at the shoulder and weighs around 175 lb (79 kg). It has a grey coat with a white underside, separated from the grey by a stripe of black, with black stripes where the head attaches to the neck, along the nose, and from the eye to the mouth and on the forehead. The mane is small and chestnut-coloured; the ringed horns are thin and straight. They are found on both sexes and typically measure 75–80 cm (30–31 in). Comparably, the gemsbok has an entirely black tail, a black patch at the base of the tail, and more black on the legs (including a patch on the hindlegs) and lower flanks. The smaller Arabian oryx is overall whiter with largely dark legs.
East African oryx live in semidesert and steppes, where they eat grasses, leaves, fruit and buds. They are able to store water by raising their body temperatures (so as to avoid perspiration). They gather in herds of five to 40 animals, often with females moving at the front and a large male guarding from the rear. Some older males are solitary. Radio tracking studies show the solitary males are often accompanied for brief periods by breeding-condition females, so it is probable they are executing a strategy to maximise their chances of reproduction.
References[edit source | edit]
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- IUCN SSC Antelope Specialist Group (2008). Oryx beisa. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 13 November 2008.Database entry includes a brief justification of why this species is of Near Threatened.
- Grubb, P. (16 November 2005). Wilson, D. E.; Reeder, D. M, eds. Mammal Species of the World (3rd ed.). Johns Hopkins University Press. ISBN 978-0-8018-8221-0. OCLC 62265494.