THEY were some of the largest beasts to ever walk the earth.

Giant woolly mammoths and rhinos roamed the frozen Ice Age tundras more than 50,000 years ago.

Now a Southampton University academic is among scientists spearheading groundbreaking research giving insight into what these iconic ancient animals ate.

Professor Mary Edwards was part of a project led by the Copenhagen University in Denmark exploring how such large mammals could survive in such a frozen wasteland.

For the first time, researchers used DNA sequences extracted from frozen soils in Siberia and Alaska-Yukon and from stomachs of the creatures preserved in permafrost of these polar regions.

Until now analyses of ancient vegetation has been based on studying fossil pollen which suggested that vegetation in cold environments was made up of graminoids such as grasses and sedges.

But this technique means they can harvest DNA which is normally lost when animals and plants decay to discover their diets.

Their results showed that vegetation there 25,000 years ago was rich in herbaceous flowering plants called “forbes” usually found in grasslands, meadows and tundra.

It suggests forbes were dominant across the landscape until graminoids and more woody plants became more prevalent.

Prof Edwards, a physical geographer who specialises in permafrost deposits, said: “Permafrost is frozen soil and sediment which acts like a giant freezer, preserving plant and animal remains from ancient ecosystems.

“By analysing this preserved DNA, we have found that flowering plants, known as forbes, were far more prevalent than previously thought.”

She said they would have been a critical source of nutrition for huge animals such as mammoth, woolly rhino, bison and horses.

She added: “Analysing plant DNA has provided us with a unique perspective on this now extinct northern ecosystem and given new insights into how such large animals could survive extreme cold and harsh ice age conditions.”