Fossils from a Laos cave provide the earliest evidence of modern humans in mainland South-East Asia. Uncovered fragments of bone belonging to Homo sapiens may date back 86,000 years, shedding new light on how our species migrated from Africa to Asia.
Since 2009, several modern human fossils – dating to between 46,000 and 70,000 years ago – have been discovered in Tam Pà Ling, a cave in north-east Laos. Now, Fabrice Demeter at the University of Copenhagen, Denmark, and his colleagues have added two more fossils to the collection.
“One of my Laos colleagues saw what we thought was a big piece of stone,” says Demeter. “After we removed it, I realised that it was white. I [then] knew it was a piece of bone.” Upon analysis, the fossil turned out to be small fragment of a human skull. The researchers also unearthed a piece of a human tibia, or shinbone.
Using radioactive isotopes to date the sediment surrounding the fossils in the cave, the team estimates they are between 68,000 and 86,000 years old. “In mainland South-East Asia, this is the first time we’ve got such old specimens,” says Demeter.
The findings suggest that early modern humans travelled to South-East Asia earlier than previously thought. Prior estimates put this at around 50,000 years ago, with these humans migrating out of Africa and beginning to populate the rest of the world, including Asia. Most people alive today are descended from these early humans, aside from Indigenous Australians, whose ancestors may have left Africa even earlier than this.
“Since we now have fossils that go back closer to 80,000 years, it tells us that there were multiple migrations out of Africa,” says co-author Laura Shackelford at the University of Illinois Urbana-Champaign.
Genetic data suggests that most earlier migrations probably failed, she says. The fossils discovered in Tam Pà Ling could belong to the ancestors of Indigenous Australians, whose remains found in Australia date back much earlier than 50,000 years ago, but with little information about where they came from. More research is needed into this, says Demeter.
“One of the most debated topics in palaeoanthropology today continues to be modern human origins,” says Christopher J. Bae at the University of Hawai’i at Manoa. “This particular study shows quite clearly that modern humans were in the region earlier than originally supposed.”