Why did Stegodon, the elephant-like animals that were once widespread throughout Asia, decline and eventually disappear?
Stegodon were a group of trunked mammals, related to (but not the ancestors of) modern elephants. As they dispersed to many of the Southeast Asian islands with scarcer food resources, they evolved to become ‘dwarfed’.
PhD candidate Mika Puspaningrum, an Indonesian woman studying at the University of Wollongong, has used chemical clues from the outer coating (enamel) of Stegodon fossil teeth, to reconstruct changes in the diets and habitats of these animals over the last eight million years.
The work is part of Indonesian-Australian research piecing together the evolution of elephants and humans, co-led by Iwan Kurniawan from the Geology Museum Bandung, and includes scientists from the Indonesian National Research and Development Center of Archaeology with international collaborators.
“Stegodon teeth from the Indonesian island of Flores show that from one million years ago, they became almost exclusively grass-eaters,” says Dr Gerrit van den Bergh, the Australian lead researcher who is Mika’s supervisor.
They suspect that as the forested areas gave way to savannahs, Stegodon may have helped maintain the grasslands—which they shared with ‘the Hobbit’ Homo floresiensis, a relative of modern humans, for almost one million years.
Despite evidence that baby Stegodon were on the Hobbit menu by 60,000 years ago, apparently this didn’t lead to their extinction. The debate now continues as to why both Stegodon and Homo floresiensis eventually went extinct around 50,000 years ago, and whether it had anything to do with the arrival of the only remaining species of human— Homo sapiens.
Credit for banner image: Kerrie Grant.