Good News, Genetic Studies Reveal Opportunities For Conservation Of The Sumatran Rhino

Badak Sumatera. (Wikimedia Commons/International Rhino Foundation)

JAKARTA - A genome study involving the latest population of the rhinos of Sumatra, inhabitants of a solitary rainforest, brings good news to scientists regarding the prospects for saving this endangered species.

The researchers found that the two wild rhino populations on the islands of Kalimantan and Sumatra have good genetic health and very low inbreeding rates.

Experts estimate that only about 80 rhinos remain after a separate population in Peninsular Malaysia went extinct in recent years. The Sumatran rhino is known to be the closest relative to the furry rhino which was among the well-known species of the last Ice Age, known for its two small horns and thin reddish-brown fur.

"With such a small population size, we would expect much higher inbreeding in the extant Sumatran rhino population. So these findings are good news for us", said Nicolas Dussex, a postdoctoral researcher at the Center for Palaeogenetics in Sweden who is helping lead the way study published in the journal 'Nature Communications' as reported by Reuters.

Sumatran rhino. (Wikimedia Commons / 26Isabella)

"In addition, while the fate of the Malaysian population is a stark warning of what might happen to the two remaining populations in Sumatra and Kalimantan, our findings suggest it may not be too late to find ways to preserve the genetic diversity of these species", Dussex continued.

In this study, researchers sequenced the genomes of seven rhinos from Borneo, eight from Sumatra and six from a population of the Malay Peninsula thought to be extinct since 2015.

The Sumatran rhino is the smallest of the five rhino species in the world, weighing around 1,540 to 1,760 pounds (700 to 800 kg). The elusive inhabitants of the rainforest, the most outspoken of the rhino species, remain solitary except to mate and raise offspring. It used to have a wide reach in Southeast Asia, from the foothills of the Himalayas to Kalimantan and Sumatra.

Poaching and the human destruction of homes have devastated its population, with its numbers falling by about 70 percent over the past two decades.

"In terms of the long-term survival of a species, genetic diversity is one of the key factors, as it allows adaptation to future environmental changes and disease", said Center for Palaeogenetics doctoral student and lead author of the study Johanna von Seth.

Sumatran rhino in the wild. (Wikimedia Commons / Willem v Strien)

"So, the fact that there is still a lot of diversity left is very promising if we can maintain it, of course assuming we can also reduce the impact of non-genetic factors", he continued.

The researchers said measures such as translocating rhinos for mating, a costly and logically challenging method, or using artificial insemination could allow for beneficial gene exchange between Bornean and Sumatran populations.

This species has shown low reproductive success in captivity and faces a high risk of inbreeding, interbreeding with close relatives, in the wild due to its small numbers.

Inbreeding creates a high risk of genetic defects and reduced genetic diversity. Scientists worry that these reports of tumors and low fertility among rhinos are evidence of a dangerous mating population.

"It is important to remember, the Sumatran rhino is still on the verge of extinction due to non-genetic factors", said Love Dalén, professor of evolutionary genetics at the Center for Palaeogenetics.

"So hopefully, although small, this result offers that if we manage to solve the problems caused by habitat destruction and hunting, there is at least the possibility that the survivors will not be perished by their poor genetic status", added Dalén.