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 The most accurate timeline yet for the demise of our closest
relatives, published on Wednesday, shows Neanderthals overlapped
with present-day humans in Europe for between 2,600 and 5,400 years
before disappearing about 40,000 years ago.
Pinpointing how and when the Neanderthals became extinct has been
tough because the mainstay process of radiocarbon dating is
unreliable for samples that are more than 30,000 years old, due to
contamination.
The latest six-year project by researchers at the University of
Oxford used modern methods to remove contaminants and accurately
date nearly 200 samples of bone, charcoal and shell from 40
important archaeological sites across Europe.
The data showed that Neanderthals vanished from Europe between
39,000 and 41,000 years ago - but rather than being replaced rapidly
by modern humans, their disappearance occurred at different times
across sites from the Black Sea to the Atlantic.
"Now that we are using better techniques, the picture is becoming
much more clear in terms of the process by which Neanderthals
disappeared from Europe," said lead researcher Tom Higham. "Our
results suggest there was a mosaic of populations."
Scientists already know from DNA evidence that there was some
interbreeding between the two groups, although it is not clear
whether this occurred once or many times. Recent studies have
suggested between 1.5 and 2.1 percent of the DNA of modern
non-African human populations originates from Neanderthals.
"In a way, our close cousins, as Neanderthals are, aren't extinct,"
according to Higham. "They carry on in us today."
Paleoanthropologist Chris Stringer of the Natural History Museum in
London, who was not involved in the research, said the new findings
were "striking" and backed up the idea that modern humans and
Neanderthals may have learnt from each other.
He believes interbreeding probably first occurred in Asia soon after
modern humans began to leave Africa around 60,000 years ago, so the
latest evidence indicates the two populations may have been in some
kind of contact for up to 20,000 years - much longer than in Europe
alone.
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NOT SO DIM-WITTED
Many scientists now reject the notion that Neanderthals were
dim-witted brutes and point to evidence of use of symbolic objects,
which may have been learnt from modern humans.
The Oxford team dated a number of items from sites of so-called
transitional stone tool industries - viewed as either the work of
the last of the Neanderthals or early modern humans - and found they
were all between 40,000 and 45,000 years old, indicating a period of
possible cultural exchange.
Interestingly, they found no evidence that Neanderthals and modern
humans lived particularly closely together. Rather, Neanderthals
probably survived in dwindling populations in pockets of Europe
before dying out altogether.
It is unclear what killed off the Neanderthals, although theories
include an inability to adapt to climate change and increased
economic competition from more agile modern humans.
While the latest work provides the most robust timeline so far of
the last days of the Neanderthals, there are still gaps in coverage,
particularly in Siberia and eastern regions of Eurasia. That is
something the researchers plan to address in follow-up
investigations.
"Ultimately, our aim is to create kind of movies that show the
arrival and departure of different sub-species of humans across
Europe," Higham said in an interview filmed in his lab. "We are
part-way towards that but there is a still a lot more work we can
do."
Some scientists have hypothesized that late-surviving groups of
Neanderthals lived in places such as Gibraltar after 40,000 years
ago, but the latest dating provides no evidence of this, according
to the Oxford team, whose findings were published in the journal
Nature.
(editing by David Stamp)
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