Secrets of the woolly mammoth's disappearance
Friday, 08 Jun 2007 15:18
Woolly mammoths lived during the Ice Age
Science In Focus
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Woolly mammoths did not die out suddenly as some have thought but instead extinction occurred gradually over thousands of years, scientists claim today.
The creatures are thought to be one of the giants of the Ice Age and some researchers thought they died because of a sudden event at the end of this period.
For the latest study, scientists lifted the DNA from the bones, teeth, tusks of the extinct mammoths.
The researchers argue that their findings revealed a 'genetic signature' of a range expansion after the last interglacial period.
Writing in the online journal Current Biology, they propose that after the mammoths' migration, the population apparently levelled off and one of two lineages died out.
"In combination with the results on other species, a picture is emerging of extinction not as a sudden event at the end of the last ice age, but as a piecemeal process over tens of thousands of years involving progressive loss of genetic diversity," said Dr Ian Barnes of Royal Holloway, University of London.
"For the mammoth, this seems much more likely to have been driven by environmental rather than human causes, even if humans might have been responsible for killing off the small, terminal populations that were left."
Commenting on the importance of the findings, researcher Dr Adrian Lister of the University College London said: "At a time when we should be very concerned about the potential extinction of many existing large mammals, studying those that occurred in the geologically recent past can provide many insights.
"Our work, together with that of others, shows that the conditions for extinction can be set up long before the actual extinction event."