Posted on 03 September 2003
DNA testing proves that Borneo pygmy elephants are an indigenous and distinct subspecies, with different characteristics from their Asian elephant cousins on mainland Asia and Sumatra.
Petaling Jaya, Malaysia - DNA tests have shown that the elephants living on the island of Borneo, shared by Malaysia and Indonesia, are an indigenous and genetically distinct subspecies of Asian elephant, with different characteristics from their cousins on mainland Asia and Sumatra. Conservation of the subspecies, which has been given the common name of Borneo pygmy elephants, should be managed separately from other Asian elephants.
Different characteristics between Borneo elephants and Asian elephants had already been recognized. “For a start, they are relatively tame and mild-tempered compared to other Asian elephants. Borneo’s elephants are also smaller in size,” says WWF-Malaysia Chairman Tengku Zainal Adlin.
There has also been a long-standing debate over the origin of Borneo's elephants — whether they are introduced or indigenous. One theory suggested that they are descended from tame elephants presented as gifts to the Sultan of Sulu by the British East India Company in the 17th century. The second theory argued that they are indigenous to Borneo, arriving from Sumatra via a bridge of swampy land when sea levels were lower during the ice age more than 10,000 years ago and then being trapped on the island after sea levels rose and severed the link with Sumatra.
The distinguishing differences coupled with the origin debate led experts to investigate whether Borneo elephants are a genetically distinct subspecies. With permission granted by the Sabah Wildlife Department, WWF’s Asian Rhino & Elephant Action Strategy (AREAS) Programme with cooperation from S.O.S. Rhino collected dung from elephants in different parts of Sabah in order to perform DNA testing on intestinal cells found in the mucus adhering to fresh dung. This technique of obtaining DNA does not harm the elephants, as they are not captured for testing.
The dung samples were sent to Columbia University’s Department of Ecology, Evolution and Environmental Biology for DNA analysis and comparison with DNA from Asian elephants from Sri Lanka, India, Bhutan, Bangladesh, Thailand, Laos, Vietnam, Cambodia, Peninsular Malaysia, and Sumatra.
The DNA analysis showed that Borneo’s elephants were isolated about 300,000 years ago from their cousins on mainland Asia and Sumatra. Since then, the elephants have become smaller with relatively larger ears, longer tails, and relatively straight tusks. The evolutionary history of Borneo’s elephants justifies their recognition as a separate evolutionary significant unit (ESU). The analysis also disproves the argument that they were introduced to the island in the 17th century.
The genetic distinctiveness of Borneo elephants makes them one of the highest priority populations for conservation. As such, they should be managed separately from other Asian elephants. They should not be crossbred with other Asian elephants in ex situ management, and research should be conducted on their reproductive rates, juvenile survival, and other indicators of detrimental effects of inbreeding.
• Dung samples were collected from the lower Kinabatangan, Kalabakan Forest Reserve, Gunung Rara Forest Reserve, and Ulu Segama Forest Reserve, Sabah.
• The study was made possible by support from the Sabah Wildlife Department, Malaysia, Columbia University, US, and WWF’s Asian Rhino and Elephant Action Strategy (AREAS) Programme, and by funding from WWF, Ms Nancy Abraham, and the US Fish and Wildlife Service Division of the International Conservation Asian Elephant Conservation Fund.
For further information
Teoh Teik Hoong
Tel: +60 3 7803 3772