Colours of Wildlife: Oribi
Created | Updated Feb 18, 2018
Oribi
Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
Again I have for you an antelope that is largely unknown, even in the places where it occurs. This is an Oribi, Ourebia ourebi. The name comes from the Nama, 'arab', which became 'orabi' in the Cape-Khoi and then 'oribi' in English. This is a small, slender and graceful antelope, related to klipspringers, dikdiks, steenboks and sunis. The species occurs patchily in South Africa, as well as East Africa, but in south-central and north-central to west sub-Saharan Africa, its distribution is continuous. It actually has quite a vast range, one of the most extensive of any African antelope. Thus it is quite strange that so few people even know of it.
The World's Biggest Dwarf
The group in which the oribi is classified, the Neotragini, is called the Dwarf Antelope tribe. It contains the tiniest antelopes in the world, the Royal and Dwarf Antelopes. The other members are also small, but of them all, the oribi is the largest. Adults reach a shoulder height of 67 cm/26" and a bodyweight of 22 kg. In this species, unusually for the antelopes, the ewes average slightly larger and heavier than the rams. Only the rams carry the straight-to-somewhat-forward-curving, sharp horns.
Oribis can be mistaken for steenboks, but have longer, more slender legs and necks, proportionally smaller ears, and more prominent white blazes on their faces. Below the ear, similar to the Mountain Reedbuck, but unlike the steenbok, they have a black patch of skin. They also have boldly bi-coloured tails, black above and white below, while the upper tail surface of the steenbuck is the same rufous colour as the body. Oribis in South Africa are also unusual in having distinct summer- and winter pelages, the sleek summer coat being replaced by a soft, dense, fleecy winter coat. They have glands between their hooves, in their groins, and beneath 'brushes' of fur below their knees and ankles. The groin glands secrete a powdery stuff which smells like facial cream – sorry, but my sources don't supply an actual brand name!
Oribi Gorge
In South Africa, oribis are associated with moist grasslands, often in mountainous or hilly (but not precipitous or steep) terrain. They're absent from the province where I live, Limpopo; they occur in some parts of Mpumalanga, and in the Eastern Cape, but are most frequent in Kwazulu-Natal, especially in the 'midlands'. One place has been named for them, the Oribi Gorge, in the south of the province, not far from the city of Durban. This is a beautiful, rugged gorge cut through the grassy terrain by the meandering Umzimkulwana River. The gorge has a length of 24 km/15 miles, a maximum width of 5 km/3 miles, and a maximum depth of 400 m/1300'. The gorge itself is actually not inhabited by the oribis! Its steep and rocky slopes are covered in forest and thicket. The oribis live in the remaining grassland above the gorge. The gorge is one of South Africa's most impressive natural features, and worth a visit.
Odoriferous Oribis
Most dwarf antelopes stay in or close to the shelter of forests and thickets. Oribis, by contrast, inhabit open grassland with at most a sparse cover of trees and shrubs. They prefer the grass quite short, though they will use patches of longer grass for shelter. The benefit from the grazing activity of herds of larger mammals, which keeps lush grass down to a short length for them. Regular grass fires can perform the same service. While adult rams like to stake out territories, especially in rutting season, they sometimes need to move away when the food runs out, to seek out lusher pastures elsewhere.
Within this open terrain, oribis depend to some degree on visual cues, like a rocking-horse running gait similar to that of reedbucks, and verbal cues like whistles and bleats, but more interestingly have adapted and elaborated the kind of scent-communication used by their forest-living forebears to a remarkable degree. An adult oribi ram has no less than fourteen different sites on his body that exude odoriferous secretions! Those on his feet and legs and in his groin mark the grasses and shrubs wherever he moves. He uses the scent glands on the inner corners of his eyes to mark tall and stiff grass stalks; he will bite off the tip of a stalk that is too tall, to make it the right height. When a female urinates or defecates, a male will come along and sniff at it, mark a nearby grass stalk, and scratch around the place with his hooves. His entire territory becomes saturated with his scent, and it gets concentrated around the ewe (or ewes – some rams are bigamists). She comes to associate his scent with her entire environment – he becomes a vital part of her world.
This kind of scent-marking evolved in the small, forest-living ancestors of oribis, who all had small territories. It is much more difficult for the oribis inhabiting their large territories of open grassland, to manufacture so much 'perfume' to scent the whole place with, and this must indeed put quite a strain on their physiologies.
While oribis today are still widespread, and common in parts of their range, they're not doing so well in South Africa. Hunting has eliminated many of them; they're still hunted in rural areas by men with teams of dogs and using flash-lights at night, or snared, in spite of being protected by law. Hunters with guns have a huge advantage, since oribis have a curious habit of, when fleeing, running for a few hundred yards and then stopping to look around at whatever disturbed them.
Aside from direct persecution, oribis also suffer from man-made changes to their environment. Much of their grassland habitat has been destroyed, turned into grain or produce farms, or planted with alien trees to use for wood. Other habitat has deteriorated, mainly because of over- or under-grazing either by domestic livestock or by mismanaged game stock. When the grass is either too tall and dense, or too sparse, or when trees and bushes encroach on grassland, it becomes unfavourable for the oribis. Some introductions into suitable habitat in large nature reserves have been attempted, but these haven't been very successful. But where oribis occur, they can actually exist harmoniously alongside domestic cattle, and private land-owners have done much to conserve them. Overall we therefore need to keep a close watch on the surviving populations, and devise specific conservation tactics to benefit them – and be patient, since results will likely only occur over the long term.
