DNA clues in ‘mammoth graveyard’ could unlock mystery of why creatures died out

An expedition into the furthest reaches of the Siberian tundra has found DNA clues to the mystery of why the gigantic beasts died out 10,000 years ago - in the stomachs of the preserved carcasses of the last few mammoths to survive on Earth.

The expedition, from Lund University in Sweden, had to travel via helicopter to an area that the researchers describe as “totally nowhere”, with no roads and no trains connecting it to the rest of the world.

Their discovery, made using DNA technology unavailable to previous teams, could solve a mystery that has divided scientists for decades - why the ‘megafauna’, large mammals such as mammoths, sabre-toothed cata and huge ground sloths died out around 10,000 years ago.

Theories as to why the animals died out range from an increase in human hunting to climate change.

But the truth could lie in the creatures’ diet, the Lund team discovered. After seven expeditions to the Arctic, Lund University geology professor Per Möller thinks the answer may lie in the plant life of the area - analyzed in soil samples, and the preserved stomachs of eight woolly mammoth carcasses.


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“My role has been to oversee the collection of a large number of soil samples which are then analysed by biologists in laboratories”, says Möller. Möller cooperated with 30 research teams from around the world to investigate the mystery of why the ‘megafauna’ began to die out.

The researchers examined plant DNA residue in soil samples and were able to get an overview of the various plant species that dominated the mammoth steppe - something unknown to previous researchers.

The researchers also analysed the stomach contents of eight large mammal carcasses found preserved in the frozen ground to get a conclusive answer to what foods the animals preferred.

The conclusion is that the mammoth steppe was much more dominated by herbs than grass during the last ice age. This may have had an impact on large mammals. A herb-dominated diet is far more nutritious than a grass-dominated one.

The study also shows that when the last ice age ended and the much more humid interglacial period began, the plant composition on the Arctic tundra changed.

“The herbs then became less dominant, and grass took over”, says Per Möller.

Per Möller says it is conceivable that this process has been a major contributing factor to why many of the large mammals became extinct about 10,000 years ago.

So far, the scientific community has believed that the mammoth steppe was completely grass -dominated, an idea that was based on analyses of pollen in soil samples. However, the vegetation composition as shown by preserved DNA in the frozen soil gives quite a different picture; the new ability to analyse the plants' DNA residue is thus highly interesting to researchers, including Per Möller.

“We will have to re-evaluate a lot of old truths”, he says of the new technology.