The 125,000-year-old stone tools were discovered from a rock shelter located just behind the white vehicle near the base of the Jebel Faya hills in the United Arab Emirates. (Above) Stone axes recovered from the site.

New Delhi, Jan. 27: Stone-age tools from 125,000 years ago discovered in the Arabian peninsula suggest that the first exodus of modern humans from Africa into Asia, and eventually India, occurred much earlier than widely believed.

The tools, found by an international team of archaeologists and scientists at Jebel Faya in the United Arab Emirates, provide fresh evidence against the hypothesis that modern humans first left Africa about 65,000 years ago.

The researchers said the tools demonstrate the presence of anatomically modern humans, or Homo sapiens, in eastern Arabia about 125,000 years ago.

The findings will appear in the US journal Science tomorrow. They corroborate earlier archaeological evidence provided by stone-age tools from Jwalapuram in Andhra Pradesh that suggested modern humans had reached southern India about 80,000 years ago.

“These findings should stimulate a re-evaluation of the routes by which modern humans became a global species,” said Simon Armitage, a researcher in physical geography at the Royal Holloway at the University of London and lead author of the study.

“We’ve pushed back the date of the earliest out-of-Africa expansion of modern humans by quite a long time, and we think we understand the geographic and climatic conditions that allowed them to cross over into Arabia,” Armitage told The Telegraph.

Although archaeologists have long debated the date of modern humans’ journey out of Africa, genetic studies, which allow scientists to explore the roots of modern human populations and prehistoric migrations, have in recent years pointed to an exodus about 65,000 years ago.

“But the location and the type of stone tools at Jebel Faya and Jwalapuram support a much earlier exit from Africa,” said Ravi Korisettar, an archaeologist at Karnatak University in Dharwad, Karnataka, who had excavated the Jwalapuram site.

Archaeologists have long suspected the validity of dates from genetic studies. While changes in genetic material over generations may show patterns of past movements of people, genetic analysis is not a precise method for dating, Korisettar said.

Armitage and his colleagues also analysed paleo-climate data that suggest that modern humans crossed the Red Sea at its narrowest point, the Bab-al-Mandab strait, into an Arabian peninsula that was dramatically different from the arid desert that it is today.

The climate data indicate that about 125,000 years ago, Arabia was much wetter with a network of lakes, rivers and green vegetation.

How modern humans crossed the Red Sea remains a mystery. “It was a period of low sea level, but they would still have had to cross about five kilometres of sea,” Armitage said. “They may have waded, swam or used a raft —we’ll probably never know.”

The actual crossing may have occurred about 130,000 years ago and the wetter Arabian habitat allowed the humans to spread into the interiors, reaching Jebel Faya by 125,000 years ago. From there, they moved across the strait of Hormuz into Iran.

A team of archaeologists from Germany, the Emirates, Britain and America excavated the Jebel Faya rock shelters, and Armitage dated the stone tools through optical studies. One of the tools was dated to 123,000 years ago, while another was 127,000 years old.

Earlier excavations in India and other parts of Asia had revealed even older stone tools crafted by Homo erectus, an ancestor of modern humans that lived from 1.8 million years to about 200,000 years ago, when modern humans first appeared.

Scientists believe the Jebel Faya and Jwalapuram dates are consistent with an earlier exit. “They had about 45,000 years to get from eastern Arabia to Jwalapuram in southern India,” said Korisettar. But what route they followed is still unclear.

Before the analysis of tools at Jwalapuram, the earliest Homo sapiens tools to be dated in India, from the central Indian river valleys, were about 40,000 years old.

The Jwalapuram tools are embedded in a layer of volcanic ash associated with an eruption in Indonesia about 74,000 years ago, which happens to be the world’s largest known eruption over the past two million years.