POINTING TO OLDER ORIGINS: A collection of Paleolithic tools unearthed from a rock shelter in the U.A.E. suggest that humans might have left Africa some 125,000 years ago--rather than 60,000 years ago as genetic data suggests
Image: AAAS/SCIENCE
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Just beyond a shallow, narrow sea lay an open topography of grassy savanna, populated by plentiful game and few predators. This watery barrier—likely not more than five kilometers wide—would have been but a small obstacle for a group of modern humans accustomed to navigating African lakes with boats and rafts. But this short crossing, enabled by coincidental climate change, might have led the species—possibly for the first time—out of Africa and into Arabia, and eventually deeper into Asia, Europe and the rest of the globe.
After finding a trove of Paleolithic stone tools in what is today the United Arab Emirates (U.A.E.), a team of researchers now proposes that just such a pivotal journey across what is now the Red Sea occurred at least 125,000 years ago—about 75,000 years after Homo sapiens are thought to have evolved and tens of thousands of years earlier than they were thought to have left the African continent. And although small watercraft certainly helped, it was a trick of climatic shifts—a window of plentiful rains on the heels of a glacial period—that made the trip possible.
Direct human fossil evidence for such an early—and southeastward—migration is still lacking, however, the sand deposits around the stone tools suggest they have been buried 100,000 to 120,000 years. A middle Stone Age residence in this area would suggest that humans reached the Arabian Peninsula not from the more-northern Nile Valley 119,000 to 81,000 years ago or from the Mediterranean Sea's shores 65,000 to 40,000 years ago—as previous evidence has suggested—but rather directly from the Horn of Africa, and much earlier.
Even with "the confounding lack of diagnostic fossil evidence," says Chris Stringer, a professor of paleontology at the Natural History Museum in London and who was not involved in the research, the new archaeological work "provides important clues that early modern humans might have dispersed from Africa across Arabia, as far as the Strait of Hormuz, by 120,000 years ago." The new findings will be published in the January 28 issue of Science, and researchers think that the results could have broad implications for thinking not just about when and where humans first decamped from Africa, but also why and how.
"The mechanisms of getting out of Africa should be understood in a different way," Hans-Peter Uerpmann of the University of Tübingen in Germany and a co-author of the new study said in a telephone conference call with reporters on Wednesday. "Up until now we thought of cultural developments leading to the opportunity of people to move out of Africa. Now we see, I think, that it was the environment that was the key."
Flakes of Jebel Faya
The site where the tools were found, Jebel Faya, is about 65 kilometers from the coast of both the Persian Gulf and the Indian Ocean. Some 125,000 years ago, it would have been a grassy home to gazelles, ibex and wild asses. But before March 2006, when the first piece of a hand ax was identified, the site was known to local research teams as simply "a nice shady picnic place for a weekend without archaeology," Uerpmann said. But once striking stone tools started turning up, researchers realized they were on to something.
At the site, which is a collapsed rock shelter, excavators found three distinct layers of ancient tools (labeled A, B and C, with C being the oldest). "Assemblages A and B were similar, but assemblage C, the lowest, was radically different," said Anthony Marks, of Southern Methodist University in Dallas and research team member. The tools from the C group, which were dated to approximately 120,000 years ago, included denticulates, end-scrapers, foliates, hand axes and side-scrapers.
"We looked at what was in southeastern Arabia at that time, there was literally nothing,", Marks said during the Wednesday call. And, as Stringer points out, "the fact that artifacts in assemblage C at Jebel Faya do not resemble those associated with contemporaneous Homo sapiens [east of Egypt] signals yet more complexity in the exodus of modern humans from Africa."
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15 Comments
Add CommentAs I understand, fossilization most often occurs in very specific conditions - usually, I think, flowing water repeatedly overlaying a carcass with sediments. If so, environments that do not contain these conditions may not produce any fossils, regardless of any species populations that may exist there.
Reply | Report Abuse | Link to thisIn this case, fossil finds do not provide any representative sampling of resident population geographical distributions, and the absence of fossil evidence does not indicate any absence of population residency.
A fascinating article that tantalises with an exciting vista of earlier human migration. But a lot more evidence will be needed to confirm if this is the case and people need to remain open minded and wait for that evidence.
Reply | Report Abuse | Link to thisWOW! I've never seen anything quite that ignorant or offensive posted here. There is only ONE species of human extant on earth now. If you don't believe me ask geneticists. No one human being is more than a fraction of one percent different than another genetically. Not only are we one species but we've got remarkably low genetic diversity for a species as numerous as we are. Written large? We're inbred as all get out. Modern human populations went through what's called a genetic bottleneck sometime in the last 80 thousand years or so. That means we nearly became extinct at some point in the relatively recent past. Every man woman and child alive today is descended from a group that was probably no larger than a couple thousand people possibly as small as 250.
Reply | Report Abuse | Link to thisThe great variety of surface variation in people is just that. Surface variation. While there are definitely some genetic distinctions from one geographical region to another and some of those distinctions are functionally important (IE specific mutations that confer resistance to parasites or the ability to digest milk into adulthood) none is sufficient to qualify any other group of humans on planet earth as a separate species. No matter how you slice it the differences are ridiculously tiny. There is more genetic variation from two different chimpanzee troops a couple miles apart in africa (Members of the same species, I might add) than there is in the entirety of humanity.
I strongly suggest you do a bit more reading... Maybe something not on a conspiracy website.
I will grant you one and only one point. Some of the differences in humans that occur regionally can be medically significant if current data are to be trusted, but again this doesn't pass muster in the big picture as a reason to define any group as being a separate species.
For the record ethical and moral people don't need a reason to avoid bigotry and racism. No justification is necessary for what is clearly ugly and wrong.
Man, the trolls come out of the woodwork on this site. Must mean SCIAM is doing a good job. The whack jobs feel threatened. Yeah I know calling them whack jobs isn't productive, but I'm having a mental health moment.
Reply | Report Abuse | Link to thisAnyway, outstanding article. :-)
Don't feed the trolls guys ......... Come on ! :)
Reply | Report Abuse | Link to thisIt is an indication of migration of a small group from Mars when Mars was alive and human beings were at the height of their civilization. Some clues may come from Mars after Russia is successful in their piloted mission to Moon.
Reply | Report Abuse | Link to thisdebu, I truly hope that was in jest. Otherwise I can't imagine why someone of your mental capacity is reading the Sci-Am website.
Reply | Report Abuse | Link to thisI agree Doug, Deb is wrong. Those artifacts are actually much older than thought. They were made by an advanced group of velociraptors, right before the big asteroid hit. Real question is, did they make it into space and survive? Think 'greys'. Note that there is no fossil evidence of H. Sapiens. Other question is: Is my theory more entertaining than Deb's? By the way, it is an interesting article.
Reply | Report Abuse | Link to thisI think this advanced group of people left some behind!
Reply | Report Abuse | Link to thisSpiff
Dispersal occurs in animal populations. Whenever a barrier can be overcome by a breeding pair or more, successful dispersal has happened.
Reply | Report Abuse | Link to thisWhat is called paleolithic includes groups of hominins that broke stone into useful tools. Paleontologists can discriminate among the techniques with which tools were made. These tools look and are described as requiring complex work.
An important point is that finders have proxy dated and found the approximate age of the tool leavers. At that time the Sahara and the Arabian deserts were quite different in climate.
It is doubtful that any significant number of preagrarian people were slaves. Expect hunters to eat meat. Hunter-gathers had to range within territories that were sufficient in size to thrive, and bringing slaves just increases mouths to feed. I leave you with a more obvious use for strangers with whom one disputes.
Significantly larger brains than our averages, were the norm until the agrarian revolution. Some theories associate larger brains with decreased disposition to subservience.
Consider that nation-states, and city-states, and their practices would be highly unlikely, as the characteristics of hunter-gatherers are individualistic relative to almost all present cultures, with bands being less than 20-30, only visiting others for short periods. The others with whom they visited were likely related, and friendly, as foot locomotion prevents breeding populations from distant travel and raiding.
Point? Commentators must look beyond their own biases.
Dominance has specific meanings in various fields of inquiry, and the pretension of dominance to which some commentators appear to adhere, is extremely temporary in a species that continually reforms coalitions in which individuals achieve social dominance.
To use resources is not dominance, but a characteristic of individuals and populations. The results of overblooming species tend to hold the seeds of their collapse.
Like other readers, I am curious as to the reasons for that population bottleneck which occurred after the period of this finding. Dispersed populations, if too thinned by a catastrophic or demographic effect, might find it hard to reconnect, and a cascade of loss occurs.
This tool in the picture, look to me like Homoerictus tools
Reply | Report Abuse | Link to thisThe tool in the picture look to me like Homoerectus tools
Reply | Report Abuse | Link to thisCan any one please tell 'why the migration along Nile is discarded and a coastal route is preferred'. Is it not a river route more vegetated and easy to get food? The earliest human being born and lived inland,is it not natural will be afraid of the vast expanse of water of the sea? Not that in this travel he had to cross long expanse of water to reach the Arabian peninsula as the sea level was very much low.
Reply | Report Abuse | Link to thisV.K.GUPTAN vkguptan@hotmail.com
I believe that most of human history is under water and once the means to study these artifacts happens the results will require rewriting the history books.It is quite possible that a number of very advanced civilizations have existed in the past 50,000 years.
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