MODERN HUMANS migrated out of Africa much earlier than realised. And their departure may have been speeded by changes in climate that made the going much easier.
New evidence from an archaeological site in the United Arab Emirates suggests that humans could have crossed to the eastern edge of the Arabian peninsula as early as 125,000 years ago. The current theories hold their departure did not take place until about 60,000 years ago. The research by an international team also indicates that the early migrants crossed the peninsula directly.
Scientists believe that anatomically modern humans had evolved in Africa by 200,000 years ago. There is less certainty about when and how they left Africa. The timing for when they departed is “a fundamental question in human evolutionary studies”, according to the researchers who discovered the new evidence.
Prof Hans-Peter Uerpmann from Eberhard Karls University in Germany led the team with lead author Dr Simon Armitage of Royal Holloway, University of London. "The deserts of the Arabian peninsula have been thought to represent a major obstacle for human dispersal out of Africa," the authors write this morning in the journal Science.
Their discovery of an ancient “toolkit” containing primitive hand axes, scrapers and perforators at Jebel Faya in the east of the peninsula raised questions, however. They established the age of the toolkit at between 100,000 and 125,000 years but it was in the wrong place, far too distant from where the humans using those kinds of tools were known to have existed. Reaching that site would also have been a huge challenge, with migration blocked by the arid Nejd plateau, plus the straits of Bab al-Mandab and Hormuz.
The researchers began studying sea level and climate change records for the region dating back 130,000 years. They found the peninsula was not so dry then and sea levels were significantly lower. The migration occurred “when the Bab al-Mandab was at a minimum”, they suggest.
A wetter peninsula would also have allowed migration “via the numerous wadi channels that extend from the Hajar mountains and into the Persian Gulf basin, passing Jebel Faya to the north and the south”, they add.
In this way these early migrants could have travelled north to the Fertile Crescent and east on to India, they argue.