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| Gemsbok |
I've previously looked at the various species of gazelle, and at the spiral-horned antelopes (which are actually "bovines"). Now it's time to look at the others.
Linnaeus' original catalogue of scientific names, published in 1758, included five species that we would now call antelopes. In that catalogue, they are listed as goats, based primarily on the shape of their horns, and therefore sit alongside the chamois and ibex. Two of these, the dorcas gazelle and the blackbuck, are now placed within the gazelle subfamily, while two others are relatively small "dwarf antelopes", which I will cover later.
The other is the gemsbok (Oryx gazella), which, despite the name that Linnaeus chose for it, is absolutely not a gazelle. He described it as living in India, which is either a mistake on his part or a staggeringly broad definition of "India", given that it actually inhabits southwestern Africa. More specifically, they are found in the wild across Namibia, most of Botswana, and the northern and western parts of South Africa. They may cross the border into Zimbabwe, and are certainly found in game reserves there, but no longer cross the Kunene River into Angola as they once did.
They were also introduced to New Mexico in the 1960s as game animals, apparently to replace native pronghorns strafed by the USAF during training missions in the 1940s. Discovering a complete absence of lions, leopards, and hyenas, the gemsbok prospered to the point that they may now pose a threat to the native ecosystem, with cougars apparently unable to take up the slack.
This is, you will note, a particularly desolate and arid part of the world, with much of it lying inside the Kalahari Desert. Indeed, gemsbok are very much creatures of the open plains, inhabiting wastelands too barren for most other animals of their size. They will enter sparse savannah woodlands when they have to, but only to cross between open spaces, perhaps fearful of what predators might be hiding there.
The word "gemsbok" comes, via Afrikaans, from a Dutch word meaning "chamois-buck", but it's hard to see why, given that they do not look even remotely like a chamois. They are, instead, moderately size antelopes, standing around 120 cm (4 feet) high at the shoulder, with both sexes having long, straight horns that can reach as much as 150 cm (4' 11") in length. They are a pale sandy colour over most of their bodies, but with a black stripe down the middle of their back and wide black stripes along the flanks. The face is white, with clear black markings, and there is a short, dark mane running down the neck. Males are slightly larger than females, but not by as much as in some other ruminants.
As one might expect, gemsbok have several adaptations that help them survive in their arid environment. Some of these are behavioural; they are most active during the cooler parts of the day and, while not truly nocturnal, also during moonlit nights. Understandably, they will seek out shade when they can find it and, when they can't (as is quite common where they live), position themselves so that the smallest part of their body is facing directly into the sun. They can also raise their body temperature by a full 4°C (7°F) during the hottest parts of the day so that they sweat less than they otherwise might.
They can go without water for protracted periods, and probably don't inhabit lands further east because the winters become uncomfortably wet; attempts by ranchers to introduce them to these areas have generally not been successful. An annual rainfall of about 30 cm (12 inches) seems to be the upper limit that they can tolerate, and even when they could forage in areas with damp soils caused by water drainage, they avoid doing so, sticking to rocky hillsides and dunes with short grasses.
They mainly eat grass, especially during the wet season when fresh sprouts appear. During the dry season, their diet becomes somewhat broader, so that they sometimes feed on shrubs and trees, and regularly dig into the soil to get at roots, bulbs, and wild cucumbers, sometimes reaching as deep as 1 metre (3 feet).
They live in small, mixed-sex herds of 5 to 40 individuals. These tend to remain in small, probably territorial regions, travelling no more than 2 km (1¼ miles) a day, unless they are spooked by a predator. Some older males, however, live on their own, keeping apart from their fellows, but able to visit multiple herds. While they can survive for days without water, they drink heavily at waterholes when they can, queuing up to do so, with the larger males pushing out everyone else to drink first - to the extent that females and young are first to die off during times of drought.
There does not seem to be a specific breeding season, with mating occurring throughout the year. Both the solitary males and those travelling with the herds get a look in, although the full details of their dominance hierarchies are not known. Newborn young are hidden in thickets, one of the few times that gemsbok will give up the advantage of open terrain with a clear view of their surroundings. They leave to rejoin the herd at three to four weeks of age, by which time their horns have sprouted. All the lactating females in a herd feed their young at the same time of day, after having rested.
The gemsbok is a relatively common animal and, partly due to ranching reducing the demand for trophy hunting and partly due to them living where nobody really wants to go, their population is thought to be stable, and likely well over 350,000. The same cannot be said for their closest relatives.
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| Arabian oryx |
It is native to the whole of the Arabian region and to the desert regions to the north, once being found from the Sinai in Egypt across to Syria and Iraq, and as far south in the Arabian Peninsula as one could go. Perhaps even more than the gemsbok, it prefers desolate desert regions, living amongst sand dunes and bare rocky plains. They can happily tolerate daytime temperatures of up to 45°C (113°F) and, while they will drink when they can, appear able to survive indefinitely without water beyond that in their food, being unaffected by droughts lasting as long as six months.
By some measures, they are more drought-resistant than a camel.
Quite how they achieve this is unclear, although we do know that they retain more water than camels do in hot and dry conditions, being able to adjust their body temperature upwards by over 7°C (13°F) to reduce sweating. Like the gemsbok, they are active only during the day in winter, but around dawn and dusk, and well into the night during the hot days of summer. In fact, they only sleep around half as much in summer as in winter, averaging 3.7 hours per day, which they do during the day, instead of at night as they do in winter. They also have adaptations that allow them to keep their brain cooler, relative to their general body temperature, than other animals (including gemsbok), likely reducing the risk of heat stroke.
They eat much the same food as gemsbok, but perhaps with an even heavier emphasis on grass. Their herds are smaller, with around ten individuals each, and are highly mobile, wandering across vast stretches of desert. There is no set pattern to these migrations, which are driven partly by their apparent ability to sense rainfall at a distance and head in the direction of the resulting plant growth. The ranges of herds overlap, without apparent territoriality.
Even within the herd, the animals travel spaced out, with females without young at the front, followed by those with infants, then the dominant males, with subordinates bringing up the rear. Each adult grazes about 5 to 10 metres (16 to 33 feet) apart from the others, making the best use of sparse resources while still ensuring that the rest of the herd is clearly visible. Dominance is established by posing and looking tough rather than by actually fighting; so far as possible, they use their horns only in defence.
Breeding, and the way they raise their young, is much the same as in the gemsbok, with no set mating season. Males are, however, less inclined to travel on their own after reaching adulthood, although it does happen.
The projects were successful, allowing the captive animals to breed and produce young. Just in time, too, since it is now thought that the last wild animal died around 1972.
Sometimes, such projects prove unable to restore any of the animals to the wild, but not so here. Reintroductions to the wild began in 1978 in Jordan and have continued since, with descendants of the original herd being shipped to many other zoos to maintain the program. The Jordan program itself failed, being suspended in 1997 due to pressures caused by an influx of refugees from the Gulf War in Kuwait, but others continued.
Today, the largest number of wild Arabian oryxes live in Saudi Arabia, followed by the UAE (although it's debated how truly "wild" some of these latter are), with smaller populations in Oman and Israel. There are even some in Jordan, with the project having restarted in 2014. The total wild population is thought to be over a thousand, and seems to be stable, retaining more genetic diversity than might be feared given their near-extinction just over 40 years ago. This population, it should be noted, is high enough that the animal is no longer officially listed as an endangered species by the IUCN, although it certainly qualifies as threatened.
Moving south again, we come to the beisa oryx (Oryx beisa). The status of this species has been debated down the years, with it being considered a subspecies of the gemsbok for much of the 20th century. However, after being raised to species status in 1997, it was proposed in 2011 that it be further split into no fewer than three species. While these new species were recognised in some publications, they are generally considered as one today, albeit divided into two subspecies. (The third proposed species apparently interbreeding too much with one of the others to receive even that much distinction).
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| Beisa oryx (southern "fringe-eared" subspecies) |
It is less desert-adapted than its kin, as one might expect given the climate in this part of Africa. Instead, its habitat can best be described as semi-arid grasslands and scrub, dry by the standards of many places, but not truly barren. So far as we know, their diet is much the same as other oryx, and they prefer open terrain with a clear view of the surroundings, avoiding, for example, areas with tall grass.
Like the other oryxes, their diet is dominated by grass. Only around 12% of their diet consists of anything else, including shrubs and roots dug up from the ground in a similar manner to the gemsbok. They live in herds of 30 to 40 individuals, and seem much more mobile than gemsbok, often travelling several miles a night; like their relatives, they can be active at various times throughout the day, only avoiding the worst of the heat.
While some males travel alone, they dominate herds when they live among them. They seem more aggressive than the other species, with fights between males being relatively common, especially when a solitary male tries to muscle in on a herd-living male with an established harem.
Beisa oryx are hunted for their meat and hides, with the latter often being used to make local clothing due to its durability. The great majority live outside of protected areas, and this has led to dramatic declines in their population, which is thought to have dropped to around half of its former number in the first two decades of the 21st century. As a result, even though there are many thousands still remaining - far more than there are of the Arabian oryx - the beisa has been considered an endangered species since 2018.
The scimitar-horned oryx (Oryx dammah) is of similar size to the gemsbok, but has whitish fur over most of the body, fading to a light reddish-brown on the forequarters, and lacking any of the black markings seen in the other species. Even the head has only a single reddish patch on the bridge of the nose, and is otherwise white. It also has much smaller scent glands in front of the eyes, although that is less obvious at a distance. The name, however, comes from the horns, which are marginally longer than those of the gemsbok, and, unlike all other oryxes, are curved, not straight, sweeping back over the body.
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| Scimitar-horned oryx |
The presence of a rainy season allows the oryx to supplement its usual diet of sandbur, panicgrass and crowfoot grass with saucer-berry, indigo legumes and wild melons. They once travelled for long distances across their range, seeking out areas with recent rainfall, travelling as the weather changed rather than along any particular route. Reports indicated that the largest female led the way, although it remains possible that she was being directed by a male further back in the herd, since males are dominant in other respects. The herds of 10 to 30 individuals travel mostly at night, staying out of the heat, and doing most of their feeding in the early morning before the sun gets too hot. They breed throughout the year except, for some reason, during a one to three-month pause in the spring when the females become temporarily infertile.
The scimitar-horned oryx, however, is no longer as widespread as it once was. The last populations north of the Sahara were wiped out in the early 20th century, leaving only those on the southern side of the desert. This was, and to some extent remains, a politically turbulent area, making any attempts at conservation difficult. Hunting for meat, hides, and trophies was the main pressure on their population, with the decline accelerating as firearms became more common. Numbers declined during World War II, possibly because of the influx of French soldiers, and those that remained took a second big hit during the 1980s civil war in Chad. Expansion of pastoral land for herding livestock, aided by digging wells in the arid landscape, added further pressure, and in 2000, the species was declared to be entirely extinct in the wild.
It had probably actually died out a few years earlier.
Examples did still exist in zoos, however, the animals' rugged physiology and dramatic appearance doubtless helping them. In fact, those that did survive descended from populations across at least the southern part of their former wide range, meaning that they maintained a fair degree of genetic diversity. In 2016, an attempt was made to reintroduce the animals to Chad. Despite this being one of the world's poorest countries, and remaining politically unstable to this day, the animals survived, with new herds being added from zoos over the ten years since.
By 2023, the herds had survived long enough that it was obvious that even wild-born oryxes must have been breeding and raising calves of their own. That, together with a minimum timeframe of five years since the reintroduction started, was enough to allow the species to be lifted out of the "extinct in the wild" category and to become an endangered species - a couple of steps up from where they had been.
We don't know exactly how many are alive today, all of them living in that one area of central Chad, but the 2023 estimate was that there were at least 140, and possibly over 500 at that time. It isn't a lot, but it's better than nothing.
The oryxes are, however, merely four out of the seven recognised species in their particular subfamily of antelopes. Next time, I will be looking at the other three, one of which may be very familiar to certain readers of my non-scientific writing...
[Photos by "pdeley", "MathKnight", Riaan Marais, and Charles J. Sharp, from Wikimedia Commons. Cladogram adapted from Bibi 2013.]
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