The Biology, Husbandry and Conservation Scimitar-horned Oryx ...

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Behavioural Ecology
JUERGEN ENGEL
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Part 1: Biology & Conservation
Prior to its extinction in the wild, the scimitar-horned oryx inhabited the arid grasslands
surrounding the Sahara (Newby, 1988). Living in this environment explains the behaviour of
the species that is characterised by crepuscular activity patterns, migratory tendencies and the
ability to adopt flexible strategies for foraging and social organisation.
Behavioural Ecology
Scimitar-horned oryx are primarily grazers, feeding on grasses and forbs when available, but
shifting to other food sources including browse when required (section 4). In its Sahelian
range, the species was noted to migrate over large distances in pursuit of adequate food and
water resources. Migrations of up to 1300km per year have been observed in the Republic of
Chad (Gillet, 1965, 1966b). The basic pattern was repeated every year: in the dry season
(March to May) the animals travelled southward, and after the first heavy rainfalls in June and
July, they moved back to the north (Brouin, 1950; Haltenorth, 1963; Schomber, 1963; Gillet,
1965, 1966b, 1971; Dolan, 1966; Newby, 1974), travelling mainly at dusk and dawn (Brouin,
1950; Gillet, 1965, 1966b, 1971). Scimitar-horned oryx are thought to have the ability to
respond to variations in air humidity over large distances, moving to areas where rainfall is
due (Gillet, 1965, 1966b; Newby, 1974).
Even when not migrating, scimitar-horned oryx were active early in the morning and late in the
afternoon, and frequently also into the night (Brouin, 1950; Dolan, 1966; Newby, 1974;
Gordon, 1991; Gordon & Gill, 1993). During the hottest hours of the day, from around 09.00 to
16.00, animals rested in the shade (Haltenorth, 1963; Kranz & Ralls, 1979; Gordon & Wacher,
1986; Wacher, 1986a). If there were no suitable trees and shrubs offering shade, scimitarhorned
oryx excavated hollows in the soil with their front hooves (Gillet, 1965, 1966b).
These activity patterns no doubt help to minimise water loss (Newby, 1975a, 1978a;
Wakefield, 1996a; Dolan, 1966; Anon, 1987a). However, the scimitar-horned oryx is also
physiologically adapted to arid environments and may go for long periods without drinking
(Dolan, 1966). During such times moisture is attained from food plants with bitter wild
melons Colocynthis vulgaris being an essential and staple water-food (Barzdo, 1982; Newby,
1988). Animals also search for plants like Indigofera viscosa late at night and in the early
morning that are densely covered with glandular hairs and produce a hygroscopic secretion,
further contributing to their water requirements (Gillet, 1965, 1966a).
A healthy adult scimitar-horned oryx has no natural enemies in its arid environment.
However, young and weak oryx may fall victim to lappet-faced vultures Torgos tracheliotus,
golden jackals Canis aureus, wild dogs Lycaon pictus, striped hyenas Hyaena hyaena, spotted
hyenas Crocuta crocuta, cheetah Acinonyx jubatus, and in former times, lions Panthera leo
(Gillet, 1965, 1966a; Newby, 1974, 1988).
Social Organisation & Behaviour
Before their extinction in the wild, scimitar-horned oryx herds are reported to have been
relatively small (Bonnet, 1909; Brouin, 1950), ranging between 10-30 animals (Rode, 1943;
Dolan, 1966; Gillet, 1971; Newby, 1974, 1975a, 1978a, 1988; Kranz & Ralls, 1979; Newby,