How elephants came to the island of Borneo has been unclear, and there are two prevailing theories as to how they arrived, according to Portugal's Instituto Gulbenkian de Ciência. One theory says people introduced elephants there about 300 years ago, while the other argues elephants arrived much earlier and diverged from Asian elephants hundreds of thousands of years ago.
But an Instituto Gulbenkian de Ciência-led team of researchers says its genetic analyses suggest a third scenario. As they write in Scientific Reports, they analyzed mitochondrial and microsatellite DNA from Bornean elephants to model their demographic history. While their modeling can't pinpoint the exact time elephants colonized Borneo, the researchers say it suggests that Borneo elephants went through a population bottleneck about 11,400 years to 18,300 years ago.
That, author Reeta Sharma notes in a statement, dates to the last glacial maximum when sea levels were much lower and elephants may have been able to travel between the islands of the archipelago to which Borneo belongs. "We cannot exclude more complex scenarios, but a historical human introduction seems very improbable, and so does a very ancient arrival," she adds.
Cardiff University's Benoit Goossens also says that understanding more about Bornean elephants will aid in conservation efforts — there are only about 2,000 Bornean elephants alive.