67907News: Hunting was just final straw for mammoth, study finds
- Mar 31, 2008
Hunting was just final straw for mammoth, study finds
March 31, 2008
Courtesy Public Library of Science
and World Science staff
Does the human species have mammoth blood on its hands? Scientists have long debated whether climate change or human hunting were primarily responsible for consigning the shaggy elephant relative to history.
Woolly mammoths in an artist's rendition. (Courtesy Mauricio Anton)
A new study uses climate models and fossil distribution to conclude that the woolly mammoth went extinct mainly because a warming climate, while hunting was the final straw.
It has been particularly hard to untangle these two potential causes of extinction, as climate change and increased human hunting are linked, the researchers said. When the climate in mammoth lands started to become too warm for the beast, this let humans invade the area. Therefore, the mammoth faced the heat and predation pressure from hunting in the same regions at about the same times.
It had also been argued that, as the mammoth had survived many previous temperature fluctuations, only human hunting that was a new condition severe enough to cause its demise.
David Nogues-Bravo of Spain's National Natural Sciences Museum and colleagues claim to have settled the debate by using mathematical modelling to separate the two factors. They estimated climate and species distribution at five different times in mammoth history-ranging from 126,000 to 6,000 years ago-considering temperature and rainfall simulations alongside the age and locations of fossils.
The results show that the mammoth suffered a catastrophic habitat loss, with the species 6,000 years ago relegated to one-tenth of the habitat available to it 42,000 years ago, when glaciers were at their biggest.
In fact, things were much worse for the mammoth even earlier, when high temperatures also restricted its habitat 126,000 years ago, Nogues-Bravo and colleagues argued. At both these times, the climate-related habitat loss would have forced the species to the brink of extinction, they said. But the nail in the mammoth's coffin 6,000 years ago was that during the later crisis, the mammoth also faced evolutionarily "modern" humans, spelling its doom.
The study is published in this week's issue of the research journal PLoS Biology.
Source: World Science
McMammoth's has a lot to answer for.
Robert Karl Stonjek