Saving the rhino gene

A two-ton rhinoceros measuring 5 ft tall and 10 ft long, with a fondness for browsing on low-lying shrubbery, hardly seems like a difficult animal to find.

A two-ton rhinoceros measuring 5 ft tall and 10 ft long, with a fondness for browsing on low-lying shrubbery, hardly seems like a difficult animal to find. Unless there are fewer than 60 left on the planet. That is the case with the Javan rhinoceros, often called the rarest large mammal on earth and perhaps the most endangered. Like its near and larger cousin, the Indian rhinoceros, the Javan has only one horn, compared with two for Africa8217;s black and white rhinos and the Sumatran of Asia. The Javan, like the Indian, also has large plates of folded skin that resemble armor but do not protect against guns.

Because they lead solitary, secretive lives in remote forests in Indonesia and Vietnam, these rhinos are very hard to study: images of them come from 8216;8216;camera traps8217;8217; activated by movement in the forest, and biologists get DNA samples from dung or from the horns and hides of dead animals. 8216;8216;It is totally amazing how little we know about these animals, their mating habits and social behaviour,8217;8217; said Dr Prithiviraj Fernando, director of the Center for Conservation and Research in Rajagiriya, Sri Lanka. 8216;8216;Till a decade ago people were debating whether the females have horns.8217;8217; They do.

Fernando was the lead author of a paper in the journal Conservation Genetics last month on the first detailed genetic study of the Javan rhino. None of the rhinos exist in zoos. Without considerable luck and daring political leadership, the last Javan rhino will vanish from the Asian mainland in the next few years, leaving only those on the island of Java, whose forebears became isolated by rising sea levels 500,000 to a million years ago.

By 1934, the species was all but extinct on the Asian mainland. Devastated by the eruption of Krakatoa in 1883, the Ujung Kulon peninsula was later recolonised by rhinos and other animals but not by humans. It has since become a national park, and strong anti-poaching measures are in place. But perversely, the rhinos8217; numbers have barely budged since 1980; the lack of human disturbance means that mature forests and exotic plants are replacing the shrubby lowland vegetation the animal prefers.

A further problem, the scientists say, is that the remaining rhino populations lack the genetic variation they need to combat disease, adapt to changing conditions and avoid the health and fertility problems that arise from inbreeding. The situation is especially desperate in Vietnam. But Fernando says, 8216;8216;There is still detectable genetic diversity within the Ujung Kulon animals, which tells us we can still save this population.8217;8217;

The task of saving the rhino is even more complicated because the Java and Vietnam populations represent different subspecies and should be managed separately to preserve any unique adaptations and mutations, said Don J. Melnick, a biologist at Columbia University and the project leader of the first Javan rhino genetic study through the university8217;s Center for Environmental Research and Conservation. But Melnick added that it might be too late to preserve a distinct subspecies in Vietnam. 8217;8217;

Gert Polet, a co-author of the Conservation Genetics paper and an adviser to the World Wide Fund for Nature8217;s programme to protect Asian rhinos and elephants, says all may not be lost in Vietnam. Security there has improved, Polet said, and government officials and local residents are more sensitive to the rhinos8217; needs. 8216;8216;It is not unthinkable that there is a male and breeding is taking place,8217;8217; he says.

MARK DERR