Windhoek - Namibia's wild horses, which inhabit the barren Naukluft plain on the country's western seaboard, remain mysterious and enigmatic, despite a contentious past lost in the obscurity of history.
The most common theory about their obscure origin involves an ex-army officer of German descent, Hansheinrich von Wolf, who early in the 20th century bred horses at his residence, Duisweb Castle, to sell to the German Schutztruppe, or military colonial force.
With the outbreak of World War 1, Von Wolf re-enlisted and was killed in the Battle of the Somme in France in 1916.
Duisweb was reportedly abandoned by his family and the horses are believed to have strayed into the Namib Naukluft, eventually remaining in the vicinity of the Garub waterhole, 160km away.
The second theory is that the horses are descendants of animals abandoned in 1915 by invading South African troops who wrestled Namibia from German control.
The horses, numbering about 100 at any given time and mostly dark in colour with full tails and manes, today confine themselves to the vicinity of the Garub waterhole, a few kilometres east of the small settlement of Aus.
They have become a frequent sight for people travelling between Aus and the harbour town of Löderitz.
Hans Roedtman, an Aus resident who has spent 30 years studying the horses, says they possess a unique gene that has assisted them in adapting to surviving in harsh desert conditions. "The population has been isolated for more than 90 years. This gene has possibly mutated in each generation as the horses have adapted to the environment," said Roedtman.
He says that although the herds seldom stray further than 25km from water, they are capable of drinking only every 30 to 72 hours.
"They drink infrequently," he said. One mare has been recorded to have spent 103 hours between drinks. Although the horses survive on the sparse shrubs and grasses scattered on the dry Naukluft plains, fodder is provided when grazing is depleted.
"We have observed them eating their own droppings in times of severe food shortages, which is evidence of the adaptations they've made to survive," says Roedtman.
They also align their bodies with the sun, Roedtman says, to minimise exposure to solar radiation. To conserve energy, the horses refrain from unnecessary play and rapid movement. "They have unique physical adaptations to survive in desert conditions that are among the harshest on the planet," says Roedtman.
But despite their tourist popularity and unique status as the world's only desert-dwelling population of wild horses, they do have detractors. Zoologist Dieter Bergström says the horses do not naturally occur in the Namib desert and cannot be classified as wild.
"The horses are not native to Namibia's natural fauna bio-diversity. Feral horses is a more apt description in this case," he said.
Bergström questioned their impact on indigenous flora.
"Oryx and springbok numbers correlate with the amount of available grazing at any given time.
"But the horse population is not subject to this natural constraint and can impact on the survival of other species," he said.
Hidipo Ya Tiva, the Namibian environmental and tourism spokesperson, said the impact of the horses was negligible and did not warrant their removal. "The horses are an important part of our heritage and a tourist attraction," he said.
Namibian law protected the horses from any form of human intervention to reduce their numbers.
"When necessary, the government does capture a number of horses to ease environmental pressures," said Tiva.
Horses earmarked for removal were captured and sold on auction.
"The horses are part of Namibia's historical landscape and there is no evidence documenting a negative impact on the bio-diversity of the Naukluft," he said.