Big Climate Change Did Not Kill Neanderthals - Study
Date: 13-Sep-07
Country: UK
Author: Michael Kahn
Using a new method to calibrate carbon-14 dating, the
international team found the last Neanderthals died at least
3,000 years before a major change in temperatures occurred.
This suggests either modern humans or a combination of
humans and less severe climate change caused the species' demise
some 30,000 years ago, said Chronis Tzedakis, a paleoecologist
at the University of Leeds, who led the study published in the
journal Nature.
"What clearly emerges from our study is we can eliminate
abrupt, catastrophic climate change," he said in a telephone
interview.
"It does point toward humans being involved as a factor."
Neanderthals were a dead-end offshoot of the human line who
inhabited Europe and parts of west and central Asia.
Despite their image as club-carrying hairy brutes, research
suggests they were expert tool-makers, used animal skins to keep
warm and cared for each other.
Most researchers believe Neanderthals survived in Europe
until the arrival of fully modern humans about 30,000 years ago
but controversial findings last year indicated they might have
survived to as recently as 24,000 years ago.
Some have used the more recent date to link the
disappearance of the Neanderthals with drastic climate changes
during the destruction of ice shelves that allowed modern humans
to thrive, the researchers wrote.
But using radiocarbon dating on sediment samples collected
from deep beneath the sea off Venezuela, the team painted a
climate picture during the time of the last Neanderthals and
found they died out long before such severe climate events.
The team found that even though temperatures were
fluctuating 30,000 years ago, the swings were not severe and
similar to climate changes Neanderthals previously withstood.
Additionally, none of the dates ranging from 24,000 to
32,000 years ago that the researchers tested corresponded with
any big climate changes.
This makes it likely that a combination of climate change
and the impact of humans was responsible for the disappearance
of Neanderthals, Tzedakis said.
One theory is that colder weather in northern regions
spurred a migration of Neanderthals and modern-day humans to
southern Europe where the last known Neanderthals lived.
"They went through these climate events before and bounced
back," Tzedakis said. "Climate on its own may not be the most
parsimonious explanation."
