In 2000, University of Tübingen paleobiologist Susanne Münzel unearthed a bear vertebra with a tiny triangular piece of flint embedded in it. The stone was likely a broken spear point, hard evidence of a successful bear hunt 29,000 years ago.
Münzel also found bear bones that had clearly been scratched and scraped by stone tools. Cut marks on skulls and leg bones showed that the bears had been skinned and their flesh cut away. "There must have been cave bear hunting, otherwise you wouldn't find meat cut off the bone," she says. Many of the bones were from baby bears, perhaps caught while hibernating.
Cave bears disappeared not long after humans spread throughout Europe. Could hunting have led to the bears' extinction? That's not likely, according to Washington University at St. Louis anthropologist Erik Trinkaus. "People living in the late Pleistocene weren't stupid," he says. "They spent an awful lot of time avoiding being eaten, and one of the ways to do that is to stay away from big bears." If hunting was an isolated event, as he argues, there must be another reason the bears died out.
Hervé Bocherens' test tubes may hold the clues. Running his white powder through a mass spectrometer, he identifies different isotopes, or chemical forms, of elements such as carbon and nitrogen that reflect what the bears were eating and how quickly they grew. After studying hundreds of bones from dozens of sites in Europe, Bocherens has found that cave bears mainly ate plants.
That would have made the bears particularly vulnerable to the last ice age, which began around 30,000 years ago. The prolonged cold period shortened or eliminated growing seasons and changed the distributions of plant species across Europe. Cave bears began to move from their old territories, according to a DNA analysis led by researchers at the Max Planck Institute in Leipzig of teeth found near the Danube River. The cave bear population there was relatively stable for perhaps 100,000 years, with the same genetic patterns showing up generation after generation. But about 28,000 years ago, newcomers with different DNA patterns arrived—a possible sign of hungry bears suddenly on the move.
But climate change can't be solely to blame for the bears' extinction. According to the latest DNA study, a Max Planck Institute collaboration including Bocherens, Münzel and Trinkaus, cave bear populations began a long, slow decline 50,000 years ago—well before the last ice age began.
The new study does support a different explanation for the cave bear's demise. As cavemen—Neanderthals and then a growing population of modern humans—moved into the caves of Europe, cave bears had fewer safe places to hibernate. An acute housing shortage may have been the final blow for these magnificent beasts.
Andrew Curry writes frequently about archaeology and history for Smithsonian.