A CHESTNUT FOAL crosses the desert sand on uncertain legs. The heat is
intense. The sun stings. But this freshly minted animal doesn鈥檛 seem to notice.
With a soft neigh it reaches its mother and begins to suckle. About 50 metres
away Piet Swiegers kneels, a notepad on his thigh, and registers the new
arrival. 鈥淭hat is already the sixth newborn foal this year,鈥� he whispers
proudly.
Swiegers, a farmer and guest-house owner from southern Namibia, has watched
the wild horses of the Namib Desert pull back from the brink. Two years ago, a
year-long drought slashed the population in half鈥攋ust 70 animals survived.
Swiegers and other volunteers had despairingly carted bales of alfalfa into the
desert to stem the massive death toll. In the end, the animals were saved by the
same deluges that brought disaster to Mozambique earlier this year and last.
鈥淣ow there are about a hundred horses,鈥� says Swiegers.
Some people think Swiegers and the others who care for these animals are
wasting their time. They argue that the horses are not native to Namibia, and
that the area reserved exclusively for them in the far south of the
Namib-Naukluft Park would be best used as farmland. But the counter-arguments
are strong. The Namib horses are the only wild horse population on the entire
African continent. What鈥檚 more, they offer an unusual insight into how an
organism can adapt to even the most unforgiving environment.
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Back at his farmhouse, Swiegers gazes out on the breathtaking sight of
twilight in the Namib. The small, light-brown hills seem like a huge velvet
carpet in the soft rays of the sinking Sun. From a distance it is hard to
believe how cruel this desert can be. The region is regularly hit by droughts
that can last up to a year without a drop of rain. Then there are the extremes
of temperature. At night the thermometer often dips to zero, while in summer,
daytime temperatures can reach 40 掳C in the shade鈥攏ot that there鈥檚
much of that. Winter conditions can fluctuate between freezing rain one week and
searing heat the next.
So, what is a herd of wild horses doing here? Swiegers looks
amused鈥攖his is the question everyone wants answered. There are many
stories, he says, but most suggest the horses arrived in colonial days. At the
start of the 20th century the German colonial armies shipped in tens of
thousands of Trakehner cavalry horses to quash uprisings of rebellious tribes
and, later, to use in First World War battles against the British. One legend
has it that shortly before the German capitulation, a cavalry sergeant set his
horses free on the edge of the Namib Desert. His last words allegedly were:
鈥淢ake a better job of it than we did.鈥�
Another story suggests that today鈥檚 animals are the descendants of horses
imported in the 1900s by Germans building a railway between Keetmanshoop and the
harbour town of L眉deritz. More romantic is the tale of the German baron
Hans-Heinrich von Wolf, who with his wife, American millionairess Jayta
Humphries, spent a fortune trying to breed a new race of African saddle horses.
They brought German Trakehners, Hackneys, English thoroughbreds and South
African Cape horses to their ostentatious home at castle Duwisib鈥攁bout 200
kilometres north of where the wild horses live today. Von Wolf was killed in
1916 in the Battle of the Somme, leaving 300 horses at Duwisib. They could have
made their way south over the decades.
Other stories do not include a colonial component. Old fishermen in
L眉deritz relate tales of a disastrous shipwreck at the turn of the 20th
century in which European horses bound for Australia managed to swim ashore. And
Namibian purists, who would rather not have colonial blood flowing in the veins
of their desert horses, say simply that the Namib horses were brought to this
region by the Nama tribe in much earlier days. The truth may never be known, but
studies of the animals are starting to separate fact from fiction.
Next morning, in the desert, the herd gathers around a stone water trough
near a dilapidated railway station. This undoubtedly is a legacy of colonialism.
A century ago, German troops tapped an underground spring to secure a water
supply for their rail link to L眉deritz. These days trains don鈥檛 stop at the
outpost once known as Garub. But this place is an oasis for the Namib horses.
The unassuming trough, fed by a permanently dripping tap, is their lifeline.
Telan茅 Greyling knows this spot well. A biologist from the University
of Potchefstroom in South Africa, Greyling has spent years here studying the
horses鈥� behaviour. She has mapped the area in which they roam, watched how they
grow and mature, and observed their mating practices and their drinking and
feeding habits. By comparing the horses鈥� behaviour with other populations of
wild horses and also closely related species living in a similar environment,
such as zebra and oryx antelopes, Greyling estimates the Namib horses have been
wild for just 10 generations鈥攖hat鈥檚 between 80 and 100 years. This fits
with the recollections of old people from the area who can remember seeing
horses around Garub before the First World War. If Greyling鈥檚 estimate is right
it rules out the possibility that the Nama tribe introduced the animals.
They may be modern in origin, but the horses have changed enough in the past
century for them to be considered as a separate and unique breed, rather than
just a curious herd of feral animals. In 1994, Gus Cothran from the University
of Kentucky, Lexington, compared blood samples taken from Namib horses with
those from the 121 horse breeds registered in a worldwide data bank. He found a
previously unknown factor in the horses鈥� blood group, which he named q. Cothran
concludes that the mutation responsible for q must have arisen after the herd
was isolated in the desert. Although it has no known survival advantage at
present, he says it may be important in the future.
Cothran鈥檚 study also found that the Namib horses are highly
inbred鈥攕econd only to Blue Arabians from the US. All this inbreeding has
left them with a genetic profile quite different from that of any other breed.
Cothran鈥檚 analysis showed that the greatest similarity is with Arabs from the US
and with another group of Arabs from Poland known as Shagyas. This means Namib
horses share common ancestors with European breeds. Once again, it seems to
validate the stories of their colonial origins.
The Namib horses bear a strong resemblance to Trakehners and thoroughbreds,
while their colouring and movement suggest Hackney and Cape horse ancestry. But
such observations are not reliable because the extreme environment will have
affected the physical appearance of the animals. Studies by retired South
African biologist Frans van der Merwe indicate, for example, that over several
generations the animals have shrunk. They currently stand at between 1.4 metres
and 1.5 metres at the withers, but van der Merwe鈥檚 analysis of their muscle and
bone structure suggests their recent ancestors were around 10 centimetres
taller. This could be an adaptation to reduce the surface area exposed to the
sun. Another change is the unusually thick coat they grow in winter as
insulation against the desert鈥檚 bitter cold.
Nobody knows whether there have also been internal physiological adaptations
in the Namib horses. But a century is a mere eye-blink in evolutionary terms, so
you wouldn鈥檛 expect to see much change at the genetic level. Besides, physical
adaptations are not nearly as important as behavioural changes, according to
Greyling. 鈥淗orses adapt their behaviour to survive in these conditions,鈥� she
says. 鈥淭hey are probably one of the most adaptable species on Earth.鈥� They have
no problem coping with a wide variety of temperatures and can live on poor
quality feed. Greyling points out that their minimum requirements of grass and a
regular water supply are similar to those of the oryx, a native of these
deserts.
Greyling鈥檚 own studies reveal that the Namib horses have learned to eke out
their water for much longer than their domesticated cousins. 鈥淭hey come to the
water trough at intervals which vary between 30 and 72 hours,鈥� she says. Some
Namib horses can last as long as 100 hours without water. It鈥檚 difficult to
estimate how much fluid they need, but Greyling suspects it is about the same as
other horses. 鈥淚 tried to quantify their water consumption once by calculating
the volume of water consumed per number of horses over one week in December with
reasonably hot temperatures and I found an average of 30 litres per horse per
day,鈥� she says.
The animals鈥� grazing habits are also unusual. Greyling discovered that when
food is available the horses graze day and night鈥�17 hours out of 24, on
average. This is much longer than other wild horses. Camargue horses in southern
France, for example, graze for 13 hours daily. The reason, says Greyling, is
probably just that it鈥檚 very time-consuming pulling the sparse blades of grass
from the sand of the Namib Desert.
For now, the herd manages to get by on meagre rations. But even these are
being eroded. As fences go up around farms and game reserves in the area, the
horses are left with little access to good pasture. They are also surrounded by
natural barriers to migration鈥攎ountains, high dunes and the Atlantic
Ocean. Besides, the dripping tap at their railroad trough ties them to this
area. All this leaves them with little room for manoeuvre when drought comes,
which it regularly does in this part of the world.
In the past, such crises have been alleviated by the efforts of Swiegers and
other volunteers. The Namibian Ministry of Environment also feeds the animals at
such times. But this policy it hotly contested. Many Namibians see the horses as
a nuisance and argue that if they cannot fend for themselves they should be left
to die of natural causes.
But what is natural? Greyling says that if the horses weren鈥檛 so fenced in
they could move to areas where the grazing was better. She also points out that
a generation ago, large herds of oryx and gazelle, 10,000 or 20,000 strong,
lived in this area. Nobody knows exactly why they are no longer here, but
there鈥檚 no doubt that human activity has played a part. 鈥淕lobal weather patterns
have changed over the past ten years and have influenced weather patterns in the
desert,鈥� she says. 鈥淎nd if the horses are not that well adapted, neither are the
other inhabitants.鈥�
For now, though, times are good and there is plenty for the horses to eat.
The herd moves on from the water trough. A young colt jumps up next to a rival
and tries to intimidate him by biting his neck. A neighing sounds through the
valley and echoes off a nearby mountain. These animals appear strong and
healthy鈥攏o longer the skeletons that walked the desert during the drought
of 1999.
But despite the breed鈥檚 remarkable resilience, these are animals living on
the brink. Those, including Swiegers, who care for these horses are under no
illusions. Their fate is in human hands. Are we going to push them over the
edge?
