Ancient finger points to earlier migration
It was a scrap of finger bone, little more than an inch long, lying unnoticed amid a desert the size of Ireland. Weathering by sand and time left archaeologists unsure even which finger it belonged to.
This 85,000-year-old fragment, however, has just helped to revolutionise our understanding of early human history because it should not have been in Arabia for another 25,000 years.
It is the latest in a series of spectacular finds that have upended palaeontology in the past three years.
Researchers think that it ties many of those previous finds together, by showing that humans could have spread across the planet, as far as eastern Asia, long before the conventional narrative believed possible.
Michael Petraglia, of the Max Planck Institute for the Science of Human History, said: ‘‘This find suggests Homo sapiens were moving out of Africa far earlier, 20 to 25 thousand years earlier, than expected.’’
Until recently there was a consensus, supported by genetic evidence, that modern humans left Africa in a wave 60,000 years ago before colonising Europe and Asia. Finds around North Africa and the Levant have challenged this, most recently the 185,000-year-old jawbone of a human found in an Israeli cave. Even more excitingly, but more tentatively, fossils in China and stone tools in Australia suggested that Homo sapiens travelled further still.
These finds were always less conclusive though, and could not be definitively linked to Homo sapiens. By showing that humans went beyond Israel, into the modern day al-nafud desert, Huw Groucott, from Oxford University and a paper co-author, argued it was now more likely these were Homo sapiens too. He thinks they may have exploited climate change to spread in waves.
In Arabic, Nafud means ‘‘void’’. The al-nafud desert is bleak, even for Saudi Arabia, but it was not always so. The few travellers to brave its caravan routes would be surprised to learn they are crunching over hippopotamus bones.
These hippos, which date from the same time as the finger bone, would have migrated into Arabia thanks to fluctuations in the monsoon, which made the Sahara and the Arabian peninsula more lush. Professor Petraglia said that this was probably behind the migration of humans too.
‘‘Animals would have been pulled into the Sahara and also out of Africa too. And of course hunters and gatherers would have been following them.’’
Chris Stringer of the Natural History Museum, speaking about the research published in Nature Ecology and Evolution, said: ‘‘It now seems likely that early modern humans were in southern China about 100,000 years ago, and they had reached Australia by about 65,000 years ago.’’