Kinabatangan: Borneo's elephants are an evolutionary significant unit (ESU)

Posted on 31 October 2003

Borneo’s Pygmy Elephant has been recognised as a separate evolutionary significant unit (ESU).
Recent DNA sampling has shed light on why the elephants of Borneo are so different from their cousins on mainland Asia and Sumatra. They are smaller in size and have relatively bigger ears and longer tails in proportion to their bodies. According to Columbia University’s Department of Ecology, Evolution and Environmental Biology for DNA analysis, Borneo’s Pygmy Elephant, as it has been called, is indeed an entirely separate population. The evidence suggests that they became isolated from other elephant populations about 300,000 years ago and developed their distinctive characteristics over this time.

The mucus adhering to fresh elephant dung contains epithelial intestinal cells which are used for DNA testing. To conduct the study, elephant dung samples were collected from different parts of Sabah, including the Lower Kinabatangan, by WWF’s Asian Rhino & Elephant Action Strategy (AREAS) Programme in cooperation with S.O.S. Rhino. The DNA samples were then compared to those of other Asian elephants from Sri Lanka, India, Bhutan, Bangladesh, Thailand, Laos, Vietnam, Cambodia, Peninsular Malaysia, and Sumatra.

Now that Borneo’s Pygmy Elephant has been recognised as a separate evolutionary significant unit (ESU), it must be considered one of the highest priority populations for conservation in the wild. It is even more important that natural forested habitat should be conserved if it is to survive.

This study was made possible by support from the Sabah Wildlife Department, Columbia University, U.S.A. and WWF's Asian Rhino and Elephant Action Strategy (AREAS) Programme. Funding was provided by WWF US, WWF-Netherlands, Ms Nancy Abraham, and U.S. Fish and Wildlife Service Division of International Conservation Asian Elephant Conservation Fund. 

For more information please contact: 
Justine Vaz 
Editor, Partners for Wetlands
The elephants of Borneo are smaller than their Asian elephant cousins elsewhere
© WWF-Malaysia/Caroline PANG

Related links