Published in The Hindu on May 12, 2011

How long back did the last of the Neanderthals walk in some parts of Europe, and for how long did they live after the arrival of modern humans into Europe?

Data gathered till date based on carbon dating techniques of Neanderthal remains found in different parts of Europe suggest that they lived till the time the first wave of modern humans reached Europe 40,000 to 30,000 years ago.

Co-existence

Evidence also suggests that modern humans and Neanderthals coexisted in parts of Europe before our close relatives vanished from the fossil records, implying the end of their presence on Earth. That the genomes of most modern humans contain 1-4 per cent of Neanderthal genes is proof of the coexistence.

The bones from which the Neanderthal DNA material was removed came from the Vindija Cave in Croatia, and were dated as between 38,300 and 44,400 years old.

But a new study published recently in The Proceedings of the National Academy of Sciences (PNAS) provides evidence that questions the very basis of our understanding of Neanderthals and human coexistence with our cousins.

According to a report in Nature, modern humans must have found Europe a ghost land with no trace of Neanderthals. Studying Neanderthal remains recovered from the foothills of the Caucasus Mountains, the authors found that our cousins had died some 10,000 years before modern humans arrived in Europe. The bones were recovered from a cave in western Russia called Mezmaiskaya.

According to the paper, the new thinking has less to do with the Neanderthal bones and more to do with the technique used to date them. They had used a more precise technique to date the fossils.

It is a well known fact that though carbon dating is robust, and is of little use while dating bones older than 30,000 years.

The limitation arises as all of the radioactive carbon gets decayed by then.

Yet, it cannot be absolutely denied that humans and Neanderthals lived as neighbours in Europe. For instance, Neanderthal remains found in Gorham’s cave in Gibraltor were dated as 24,000 years old, and are well within the upper limit of carbon dating usefulness.

So did any interbreeding between humans and their cousins take place in such places as Gibraltor, though not widespread in Europe? For that matter, how and when did the interbreeding ever take place?

Middle East

The implication of the PNAS study is that the genome admixture never took place in Europe. If at all, it could have and should have taken place well before humans arrived in Europe — probably in the Middle East.

“My gut feeling would be that probably the latest Neanderthals and the earliest modern humans may have overlapped for a bit, but not for too much,” Thomas Higham, a palaeoanthropologist at the University of Oxford, UK., and co-author of the PNAS study was quoted as saying in Nature.

Dr. Higham and other co-authors have taken upon themselves the task of accurately dating more Neanderthal remains.

This is to arrive at a timeline of their disappearance from Europe, and probably pinpoint the closer approximation of the time when we lived together with our relatives and the location where such coexistence happened.