Archaeologists working in the Arabian peninsula are re-documenting the first human migrations out of Africa, and offer new evidence that modern humans reached the Persian Gulf as much as 65,000 years earlier than previously believed.
The international team of researchers said the modern humans might have followed a direct route to the Arabian Peninsula, heading across the Red Sea, rather than traveling via the Nile Valley or the Near East as previous studies had suggested.
The researchers, led by Hans-Peter Uerpmann from Eberhard Karls University in Tübingen, Germany, discovered an ancient human toolkit at the Jebel Faya archaeological site in the United Arab Emirates, which resembled technology used by early humans in east Africa but not the craftsmanship that emerged from the Middle East.
The toolkit included relatively primitive hand axes, perforators and scrapers, suggesting that technological innovation was not necessary for early humans to migrate to the Arabian Peninsula.
The researchers calculated the age of the stone tools using a technique known as luminescence dating, and determined that the artifacts were about 100,000 to 125,000 years old.
"These 'anatomically modern' humans — like you and me — had evolved in Africa about 200,000 years ago and subsequently populated the rest of the world," said Simon Armitage from Royal Holloway, University of London, lead author of the study.
"Our findings should stimulate a re-evaluation of the means by which we modern humans became a global species."
The researchers also analyzed sea level and climate-change records for the region during the last interglacial period, approximately 130,000 years ago. They determined that the Bab al-Mandab Strait, which separates Arabia from the Horn of Africa, would have narrowed due to lower sea-levels, allowing safe passage prior to and at the beginning of that last interglacial period.
At that time, the Arabian Peninsula was much wetter than today, with greater vegetation cover and a network of lakes and rivers. This would have allowed early humans access into Arabia and then into the Fertile Crescent and India, the researchers said.
"Archaeology without ages is like a jigsaw with the interlocking edges removed — you have lots of individual pieces of information but you can't fit them together to produce the big picture," said Armitage.
"At Jebel Faya, the ages reveal a fascinating picture in which modern humans migrated out of Africa much earlier than previously thought, helped by global fluctuations in sea-level and climate change in the Arabian Peninsula."
The study appears in the January 28 issue of the journal Science.