AS THE numbers of a critically endangered species continue to decline, a point is reached where difficult decisions must be made. Should the few remaining individuals be left alone or caught and transferred to safer locations?
Is a captive breeding programme feasible? Catching wild animals is always risky, no trapping regime is completely safe, tranquillising drugs have side effects and anaesthesia carries risks. Being transported to unfamiliar locations stresses animals and creatures taken from the wild seldom prosper in captivity.
Even if a breeding programme succeeds, returning captive-bred young to the wild is never easy. Waldrapp ibis chicks, for example, were successfully raised under artificial conditions but, when released, they couldn’t find food or avoid predators. Trumpeter swan cygnets migrate with their parents, learning the routes from them. Hand-raised cygnets, deprived of this vital parental guidance, didn’t know which way to fly at migration time. They had to be shown where to go by following a micro-light aircraft. It cost millions of dollars to reintroduce captive-bred condors to California but the birds are dying of lead poisoning. They feed on the carcasses of deer shot by hunters. Intervention may offer a cure which is sometimes worse than the disease but, with a species on its last legs, it may be the only option. Conservationists are damned if they interfere and damned if they don’t.
Now it’s the turn of the Indonesian authorities to face some hard decisions. They are custodians of two of the world’s rarest mammals, the Javan and Sumatran rhinos. BBC News screened footage, recently, of three Javan rhino calves. They were filmed in their last stronghold, the Kulon National Park. This brings the number of Javan rhinos to 60, a good news story.
Vietnam had a small population of the Javan species. In 2011, poachers killed the last one, cutting off its horn to sell on the black market. The extinction in Vietnam is particularly poignant. Against the odds, the species had survived defoliation and the destruction of forests during ‘the American war’. The rhinos there were of a distinct sub-species, now no more. If the Indonesians don’t get their act together, the Sumatra rhino may suffer a similar fate.
The Sumatran species is shy and elusive. Visiting the jungles of Borneo some years ago I had vague hopes of seeing one. However, my expert local guide soon disabused me of that notion; encounters with this animal are so rare it wasn’t filmed until 2007.
First described scientifically in 1814, the Sumatran is the smallest of the world’s five surviving rhino species. Also known as the ‘hairy’ rhino, it has a reddish coat. Whereas the other two Asian species have one horn, this has two. The horns, consisting of compacted hair, are widely sought by Chinese medicine practitioners whose insatiable demands have driven the species to the brink of extinction. There were around 600 animals in 1985. Only three populations remain in Sumatra and one in Borneo.
Scientists from the University of Massachusetts have carried out a detailed survey of the species. Teams, expert in detecting signs of the rhino’s presence, have visited all the known haunts. They estimate that between 87 and 170 individuals survive in Sumatra. Borneo’s tiny rhino population, they say, is no longer viable. ‘Occurrence was negatively correlated with the presence of roads’ they note; this is an animal intolerant of human encroachment.
The Massachusetts’ surveyors think the species can still be saved. They have identified ‘intensive protection zones’, inside which rhinos would be safe. The small isolated populations, they recommend, should be consolidated and the proportion of breeding age females determined to ensure the amalgamated groups will be self-sustaining. Such measures are bound to be intrusive but the authorities, they warn, must ‘recognise the cost of doing nothing’.
© Irish Examiner Ltd. All rights reserved