17 June 2010, by Tamera Jones
Cave lions probably became extinct across Europe and Asia 14,000 years ago because a warmer climate drastically reduced the availability of their favourite hunting arenas, say scientists.
Around 1000 years later, the lion also went extinct in Alaska and the Yukon in north-west Canada.
The researchers say as the climate warmed around 14,700 years ago, forests and shrubs steadily replaced the open, steppe-like environment that had dominated for thousands of years, reducing the amount of clear space for the lion to hunt in.
'We can't say exactly why cave lions went extinct, but what we can say is that there's a definite correlation between climate change, vegetation change and the lion's extinction a few hundred years later,' says Professor Tony Stuart from the Durham University, who led the research.
'What is clear is that as the climate changed the environment, this had a big effect on everything.'
Professor Tony Stuart, Durham University
'At the moment, we have no idea why there's a 1000 year gap between the cave lion's extinction in Eurasia and its extinction in Alaska and Yukon,' he admits.
Although the cave lion's modern equivalent (Panthera leo) is now only found in Sub-Saharan Africa and in a wildlife sanctuary in north-west India, its long-extinct relative roamed the plains of Europe, northern Asia and Alaska and northwest Canada from around 60,000 years ago until about 14,000 years ago.
From the numerous fossils dated from the same period, scientists know that the lion's preferred prey were probably bison, reindeer, horse, giant deer and musk ox.
Before this research, many scientists thought that the cave lion (Panthera spelaea) may have gone extinct because its prey went extinct and the lion slowly ran out of food.
'We've pretty much ruled this out now,' explains Stuart. 'Most of the cave lion's likely prey survived for thousands of years after the cave lion went extinct. The only one that went extinct around the same time was the woolly rhino and this is unlikely to have been a major prey item.'
Stuart and his colleague Professor Adrian Lister from London's Natural History Museum report in Quaternary Science Reviews how they built up a dataset of 111 carbon dates, including 93 new dates on cave lion bones or teeth from museums in Europe, Russia and North America.
The bones and teeth came from all over the cave lion's range in Europe, northern Asia, Alaska and The Yukon.
Their results suggest the cave lion went extinct around about the same time across Europe and northern Asia. The most recent date came from a cave lion skeleton found in France. Carbon dating revealed that this individual died about 14,141 years ago.
They found the youngest bones from Alaska and The Yukon region dated back to 13,300 and 13,800 years ago.
Other researchers have argued that the arrival of humans on the cave lion's patch may have contributed to its extinction.
'So far, there's no strong evidence for this. Although more research looking at the timing of the arrival of people in the area would help resolve this.'
'What is clear is that as the climate changed the environment, this had a big effect on everything,' says Stuart.
The modern Asiatic lion reclaimed much of south-eastern Europe around 6000 to 8000 years after the cave lion went extinct in Eurasia.
'It's remarkable that the modern lion re-colonised a large region of south-eastern Europe not that long after the cave lion disappeared,' adds Stuart.