Study blames humans for prehistoric bear demise
August 15, 2019
Scientists said on Thursday that the decline of a prominent prehistoric cave bear coincided with the arrival of Homo sapiens in Eastern Europe.
The research, published in the Scientific Reports journal, blamed human activities rather than cooling in the Ice Age for the extinction of the strictly herbivorous species.
Researchers reconstructed the past population dynamics of the cave bear by obtaining data from 59 bear caves unearthed at 14 sites in France, Germany, Italy, Poland, Serbia, Spain and Switzerland.
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The data revealed that the cave bear's population saw a decline around 50,000 years ago, the same time when Homo sapiens arrived in Europe. A major population decline began about 40,000 years ago as Homo sapiens spread across the continent. The cave bear eventually went extinct about 20,000 years ago.
The cave bear, whose scientific name is Ursus spelaeus, inhabited Europe in the Ice Age alongside animals like the cave lion, woolly rhino, woolly mammoth and steppe bison. The bear was as big as a polar bear and was depicted in prehistoric cave paintings.
Climate cooling or human actions?
"There is more and more evidence that modern humans have played a determinant role in the decline and extinction of large mammals once they spread around the planet, starting around 50,000 years ago," said biogeologist Herve Bocherens of the University of Tübingen in Germany.
"This happened not just by hunting these mammals to extinction, but by causing demographic decline of keystone species, such as very large herbivores, that led to ecosystems' collapse and a cascade of further extinctions," Bocherens added.
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Scientists have long debated whether the cave bear extinction was a result of cooling climate that reduced vegetation crucial to their diet or human hunting and encroachment upon bear caves. But paleogeneticist Verena Schuenemann of the University of Zurich said the latest study discovered that the cave bear's decline predated climate cooling associated with the most recent Ice Age.
Schuenemann said the bear's population had remained stable during two long cold stretches and multiple other cooling periods.
Fresh evidence
The study claims that the arrival of Homo sapiens, which originated in Africa more than 300,000 years ago and later spread worldwide, presaged doom for numerous species across Eurasia, the Americas and Australia.
Scientists say that before the arrival of Homo sapiens, the cave bear's population had remained robust even though it shared its territory with another human species, the Neanderthals, who also went extinct after Homo sapiens invaded Eurasia.
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