London: Flowering plants may have been a critical source of nutrition for large ancient mammals, shows a new research.
Using DNA testing, an international team of researchers has unearthed a unique view of the diet of large mammals which roamed the northern hemisphere in the last ice-age.
The researchers, led by the University of Copenhagen, Denmark, sequenced DNA taken from samples of frozen soils and the stomachs of creatures preserved in the permafrost of Siberia and Alaska-Yukon -- an area many times the size of Britain.
Permafrost is frozen soil and sediment which acts like a giant freezer, preserving countless plant and animal remains from ancient ecosystems.
"It is ideal for this kind of study because the DNA is not lost to the normal processes of decay," said professor Mary Edwards from the University of Southampton in Britain.
The results show that nearly 25,000 years ago, vegetation in this area was rich in `forbs` - herbaceous flowering plants usually found in grasslands, meadows and tundra.
"By analysing this preserved DNA, we found that flowering plants, known as forbs, were far more prevalent than previously thought," Edwards added.
The study shows they may have been a major source of nutrition for huge animals such as mammoth, woolly rhino, bison and horse.
Until now, research on vegetation over the past 50,000 years has been based mainly on studying fossil pollen, showing that vegetation in cold environments, supporting large herbivores, was mainly made up of graminoids - plants such as grasses and sedges.
Analysing plant DNA gives new insights into how such large animals could survive extreme cold and harsh ice-age conditions, Edwards said.
The findings were published in the scientific journal Nature.