Woolly Mammoths Were Killed Off by Trees
Mon, Dec 17, 2007
Cavemen have been getting a bad rap long before that awful show based on the Geico commercials came out.
For years we’ve taken it as gospel truth that the woolly mammoth was hunted to extinction by our hairy ancestors. Some scientists, however, are suggesting that what wiped out the mammoth was not hunting, but trees.
It is much easier to picture the violent extinction of a species than the opposing scenario. We can easily imagine fur clad hunters stabbing the giant beasts with spears until one day there were no more left. You could even picture the hair covered animals being too hot to survive in the rising temperatures at the end of the ice age. It’s a bit harder to imagine the mammoths being killed off by a lot of trees.
We’re not talking about any Lord of the Rings style fighting trees or anything, although that would be a much cooler article. The trees were just regular forests which expanded to previously uncovered territory at the end of the last ice age, but their marching expansion still spelled doom for the elephant relatives.
It all comes down to food. Mammoths thrived most in large areas of frozen grassland. Around 10,000 years ago, temperatures started to rise. The frozen grasslands where the animals lived and fed started to be replaced by forests expanding from the warmer climates. No more frozen grasslands meant no more food.
University College London palaeobiologist Adrian Lister conducted the study. Lister analyzed the DNA from hundreds of mammoth fossils, and found that the animals changed so slightly over the course of 20 thousand years or so that they would have been unable to adapt to the new environment.
Lister said: “The DNA we have been able to extract from mammoth bones is like a clock and allows us to trace the evolutionary story in great detail now.”
He thinks the story of the mammoths went something like this, saying:
“In the middle of the last ice age, around 30,000 years ago, there were millions of mammoths roaming over a huge area. Around 20,000 years later there were hardly any left. As the forests moved in, the mammoths were pushed out of their normal habitat. These animals are mostly governed by vegetation rather than climate and so they were squeezed into very small populations as the forests took over the cold grasslands. I don’t think that people played a major role in wiping them out, although they may have pushed those final populations over the edge. The major impact factor was the change in the vegetation from grassland to trees.”
There have been other recent suggestions as to how the mammoths became extinct. An American research team suggested that meteorites bombarding the earth caused the demise of the animals. They found tusks that had been hit with shrapnel from the meteorites in Alaska recently.
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: Woolly Mammoths Met their Match: Legions of Trees - Ecoscraps Says:
December 17th, 2007 at 10:51 pm[...] For years we’ve taken it as gospel truth that the woolly mammoth was hunted to extinction by our hairy ancestors. Some scientists, however, are suggesting that what wiped out the mammoth was not hunting, but trees. As the last Ice Age melted, forests expanded and the Mammoths’ grazing grounds shrank until the Mammoths were no more. [...]
January 6th, 2008 at 5:21 am
This is an article from the Peoria Journal Star on a discovery I made. See what you make of it.
Mammoth may aid climate research
Lincoln College Mammoth could provide insight into how modern animals will react to climate change
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Friday, January 4, 2008
By CHRIS YOUNG
of Gatehouse News Service
LINCOLN - Parts of a woolly mammoth discovered in Logan County in 2005 may provide clues to how modern birds and animals could react to climate change.
Jeffrey Saunders, curator and chairman of geology at the Illinois State Museum, said the discovery of the Lincoln College Mammoth by student Judd McCullum in 2005 surprised scientists when it turned out to have lived much more recently than anyone thought.
Scientists thought the tusk and tooth would date to about 22,000 years ago, a time consistent when mammoths and mastodons were roaming Illinois and glaciers were still part of the landscape.
Those discoveries along with another tooth and a partial jaw discovered recently by McCullom’s professor, Dennis Campbell, were found to have been from an animal living in Logan County about 13,500 years ago, well after the last glaciers retreated north.
Woolly mammoths are supposed to have inhabited the cold, harsh and mostly treeless plain at the edge of the ice sheets. The Lincoln College mammoth lived more than 400 miles away from that environment and probably never saw glacial ice.
Pollen records show trees such as black ash dominating at that time, as spruce - normally associated with colder climates - was starting to decline.
“The environment is out of whack according to conventional wisdom,” Saunders said.
Other mammoth discoveries with late dates have left scientists scrambling to explain why the creatures were still around. Usually, the explanation comes around to some sort of refuge, or microclimate, being present where Ice Age conditions persisted, possibly because of wind coming off glaciers that kept a region cool.
Now, Saunders says, the refuge explanation may not be necessary. The mammoths may simply have stayed where they were born.
“It was a robust, long-lived male,” Saunders of the Lincoln College mammoth. “If it wanted to move, it could have.
“It made do.”
So what was the mammoth doing in a moist, even swampy environment in Logan County so late in the Ice Age?
The answer may give scientists some insight into how present-day birds and animals react to climate change, a hot topic among researchers, politicians and the general public.
Saunders says research shows DNA of Arctic foxes that lived in central Europe during the Ice Age does not appear in Arctic foxes living in far north regions today. That could mean the foxes living in Europe failed to adapt to changing climate and did not simply move north as the ice sheets fell back. They died out, and their distinct DNA with them.
Could the same be said for the Lincoln College Mammoth? Did mammoths and other large Pleistocene mammals stay put and fail to migrate with changing conditions?
If that turns out to be the case, present-day animals could face similar circumstances.
“It is unlikely that animals will be willing to move northward as climates move northward,” he said. “They will be overwhelmed by what happens to them.”
Even if animals are willing to migrate, some plants upon which they depend may not make the transition to new locales, especially if the soil or other factors do not favor their growth, even if temperature and rainfall do.
There are three main theories as to why large Pleistocene Era mammals became extinct. Most scientists believe climate change, hunting by early human inhabitants, some kind of disease - or perhaps a combination of these - spelled the end.
Seeking answers to all of these questions will make for plenty of work for scientists for years to come.
“You don’t get bored because something new always comes about,” said Saunders, who marks 30 years with the Illinois State Museum in 2008. “That’s the way science works.”
January 6th, 2008 at 7:06 am
The most important lesson I came away from intro history a few decades ago was that when there are multiple plausible theories about causation of something, they are likely all true to some extent, the old blind guys figuring out an elephant routine. So, eco changes, disease carried by humans and their living baggage, (domesticated critters) and the old over-hunting by bigger brained simians are likely all true. But go ahead and argue it for another 50 years, it at least gives an excuse for more publishing.