Re-examination of two teeth found in a Sumatran cave in the 1880s has filled a major gap in our picture of human migrations, revealing that modern humans were living in Indonesia sometime between 63,000 and 73,000 years ago.
Just a few weeks ago, evidence placed humans in northern Australia 65,000 years ago. Even before that, evidence of the presence of modern humans in Australia predated anything found in South East Asia. Yet to have got there from Africa, we must have come through Indonesia. (Unlike trapdoor spiders, humans didn't raft across the Indian Ocean).
In Nature, scientists from Indonesia, Australia, and Europe combine to show that two teeth found at Lida Ajer, eastern Sumatra, came from modern humans, and were found in a layer of sediment 63,000-73,000 years old. Although the teeth were dug up more than a century ago, the nature of the cave floor gave the modern team confidence in identifying their original resting place.
Lida Ajer Cave was first excavated by Eugene Dubois, the anthropologist who discovered “Java Man”, a find that demonstrated the spread of Homo erectus beyond Africa. Dubois located two teeth he thought might have belonged to humans, but science at the time was unable to confirm their species. He also left sketches of the cave itself and a map of how to find it, but according to Dr Kira Westaway of Macquarie University, Sydney, the map was sufficiently vague that modern scientists have struggled to follow it. Westaway told IFLScience that locals all have different ideas as to which of the many caves in the area is Lida Ajer.
In the meantime, techniques for identifying the species from which the teeth came advanced. Seventy years ago, the possibility the teeth were from orangutans was ruled out, but while research at the time pointed to them being from modern humans, rather than Homo erectus or Neanderthals, anthropologists were not sufficiently convinced to consider the implications.