Endangered Sumatran Rhinoceros Displays Surprisingly Good Health, Genome Research Reveals

Genome research on the remaining Sumatra rhinoceros populations offers positive prospects of saving the endangered species from extinction, according to a report from Reuters.

In the study, "Genome sequencing delivers hope and warning for the survival of the Sumatran rhinoceros," and published from Nature Communications, scientists from Stockholm University said on Monday that their research on two wild rhino populations in the islands of Borneo and Sumatra showed surprisingly good health and unexpectedly low levels of inbreeding.

Sumatran Rhinoceros, Close Descendant to Ice Age Wholly Rhinos

Researchers predict that about 80 of the rhino still exists after another population on the Malayan peninsula went extinct. The Sumatran rhinoceros is the nearest existing relative of the wholly rhinoceros that lived in the Ice Age. It is known for its reddish-brown hair and two small horns.

Researchers expect much higher inbreeding among extant Sumatran rhinoceros populations given their small population sizes at present, a Science Daily article said. They stress that the extinction of rhinoceros' Malaysian population serves as a stern warning of the two remaining populations in Borneo and Sumatra suffering the same fate. Yet, the study suggests it is not too late to save its genetic diversity.

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The scientists sequenced the genomes of seven Borneo rhinos, eight others from Sumatra, and another six from the Malay Peninsula population that since 2015 had been considered extinct.

The Sumatran rhinoceros is known as the smallest among the five existing species in the world, weighing around 700 to 800 kilograms (1540 to 1760 pounds). These rhinos inhabited rainforests and have been observed as the most vocal species. They are mostly solitary, except when mating and rearing offspring. They lived in the foothills of the Himalayas, down to Sumatra and Borneo in Southeast Asia.

Sumatran Rhinoceros on the Brink of Extinction

Habitation destruction and poaching have claimed its population, with numbers dropping by around 70 percent in the past two decades, as they fall to the brink of extinction, a BBC report said.

Researchers said genetic diversity is a key factor in the survival of the species because it enables their adaptation to possible environmental changes or diseases. As such, having a lot of diversity is a good sign if it can be maintained by reducing the effects of non-genetic factors.

They said steps, which include translocating rhinos for mating, which is an expensive and difficult process, or artificial insemination could lead to an advantageous exchange of genes between the populations in Borneo and Sumatra. The species exhibited low reproductive success while in captivity and faced an elevated risk of inbreeding, which means mating with close relatives due to its small numbers.

Inbreeding, however, would cause an increased risk of genetic flaws and lowered genetic diversity. Researchers feared that the reported existence of low fecundity and tumors were proof of a precariously inbred population.

Study Shows Hope for the Sumatran Rhinos

The Sumatran rhino, the researchers said, remains on the verge of extinction because of non-genetic factors. But there is hope with the study findings that the problem caused by poaching and habitat destruction could be solved. In doing so, there is an opportunity that survivors will not be ill-fated due to their poor genetic status, they said.