At the beginning of the 21st century giant sable, endemic to Angola, were believed to be extinct. In 2005 a small herd of female sable was caught on camera in Cangandala National Park – the first known photograph of giant sable since 1982.
The rediscovery of the species after the Angolan Civil War brought a new set of challenges for ecologists. In the absence of mature sable bulls, the last remaining female sables had hybridised with a solitary roan bull. Certain species will cross-breed when there is a lack of suitable mates. Even more unexpected, however, was the ability of the roan-sable offspring to breed, resulting in backcrosses.
“A backcross is the result of crossing a first generation hybrid with one of the parental species,” explains Pedro Vaz Pinto, conservation director of Kissama Foundation, the local non-governmental organisation behind The Giant Sable Conservation Project (GSCP).
When Vaz Pinto intervened in 2009 the herd consisted of nine pure giant sable females and nine hybrids. The hybrids were contained and sterilised, and pure sables were introduced from Luando Reserve to improve gene flow. This issue was resolved between 2009 and 2011. Cross-breeding occurred because roan and sable occupy overlapping niches and have similar social structures; both species are exclusive and will not tolerate other herbivores in their herd. However, unlike sable that mate in spring, roan tend to breed all year round, which makes roan bulls less territorial, whereas sable bulls are extremely aggressive.
In the absence of mature sable bulls, the last female sables hybridised with a solitary roan
Currently, there are an estimated 150 giant sable in Luando Nature Reserve and about 80 giant sable in Cangandala National Park. “Giant sable have never occurred outside these two protected areas,” Vaz Pinto says, “with the exception of a few dispersing animals in the 100km that separates the two conservation areas. Giant sable are miombo woodland specialists living in open forests that only grow in dystrophic soils. They have adapted to an ecosystem that is subject to more rainfall than anywhere across other sable’s distribution,” he adds.
With the sable breeding dynamics under control, the main threat to the sables is uncontrolled poaching. Gin traps and snares around waterholes are regular occurrences. In order to protect the remaining giant sable, GSCP set up a shepherd programme, recruiting local community members as law enforcement. The Angolan government has deployed rangers in areas where giant sable occur, in addition to the privately funded GSCP’s shepherd programme.
The project’s long-term goals include preventing agricultural encroachment and the continued protection of the sable. The occasional rotation of bulls between parks will maintain genetic diversity.
There are four subspecies of sable: southern, eastern, Zambian, and giant. According to Vaz Pinto, the most obvious difference between giant sable and the other subspecies is the size of the bulls’ horns. Mature giant sable bulls are notably bulkier and have longer and thicker horns between 52–58 inches on average.
Written by Georgina Lockwood
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