Washington, Nov 26 : A new study by scientists has revealed that giant cave bears that once inhabited a large swathe of Europe, died out 27,800 years ago due to climate change, around 13 millennia earlier than was previously believed.
The new date coincides with a period of significant climate change, known as the Last Glacial Maximum, when a marked cooling in temperature resulted in the reduction or loss of vegetation forming the main component of the cave bears' diet.
Researchers suggest it was this deterioration in food supply that led to the extinction of the cave bear, one of a group of 'megafauna', including woolly mammoth, woolly rhinoceros, giant deer and cave lion, to disappear during the last Ice Age.
They found no convincing evidence of human involvement in the disappearance of these bears.
The team used both new data and existing records of radiocarbon dating on cave bear remains to construct their chronology for cave bear extinction.
"Our work shows that the cave bear, among the megafauna that became extinct during the Last Glacial period in Europe, was one of the earliest to disappear," said Dr Martina Pacher of the Department of Palaeontology at the University of Vienna.
"Other, later extinctions happened at different times within the last 15,000 years," she added.
Many scientists previously claimed that cave bears survived until at least 15,000 years ago, but Dr Pacher and Professor Anthony J. Stuart of the Natural History Museum, London, claim that the methodology of these earlier studies included many errors in dating as well as confusion between cave bear and brown bear remains.
The pair also concluded, from evidence on skull anatomy, bone collagen and teeth, that these extinct mammals were predominantly vegetarian, eating a specialized diet of high-quality plants.
Compared with other megafaunal species that would also become extinct, the cave bear had a relatively restricted geographical range, being confined to Europe, which may offer an explanation as to why it died out so much earlier than the rest.
"Its highly specialized mode of life, especially a diet of high-quality plants, and its restricted distribution left it vulnerable to extinction as the climate cooled and its food source diminished," said Dr Pacher.