Lola Gayle, STEAM Register
Based on an isotope analysis of collagen from the bones of an extinct cave bear, Senckenberg scientists say the large mammals most likely were very picky eaters, subsisting on a purely vegetarian diet. According to their study, the team also proposes that it was this inflexible diet that lead to the bear's extinction some 25,000 years ago.
Modern brown bears (Ursus arctos) are omnivores, meaning they consume everything from plants, mushrooms, berries, smaller mammals, fish and insects. But the cave bear is a different story, according to Professor Dr. Hervé Bocherens of the Senckenberg Center for Human Evolution and Palaeoenvironment (HEP) at the University of Tübingen.
"According to our newest findings, these extinct relatives of the brown bear lived on a strictly vegan diet," he said in a statement.
The cave bear (Ursus spelaeus) lived in Europe during the Pleistocene and became extinct during the Last Glacial Maximum. Cave bear skeletons were first described in 1774 by Johann Friederich Esper in his book Newly Discovered Zoolites of Unknown Four Footed Animals. While scientists at the time believed the skeletons could belong to apes, canids, felids, or even dragons or unicorns, Esper postulated that they actually belonged to polar bears (Ursus maritimus). Twenty years later, Johann Christian Rosenmüller, an anatomist at the Leipzig University, gave the species its binomial name.
Cave bears, which ranged from Northern Spain to the Urals, were noticeably larger than their modern-day relatives. Despite their name, they did not actually live in caves but only used them for hibernation, the researchers said. Nevertheless, the occasional death of animals in various European caves over several tens of thousands of years eventually led to enormous accumulations of bones and teeth from these large fur-bearing animals.
Several of these bones, which were found in Belgium's Goyet Cave, were analyzed by Prof. Bocherens and an international team of scientists from Japan, Canada, Belgium and Germany.
"We were particularly interested in what exactly the cave bears ate, and whether there is a connection between their diet and their extinction," Prof. Bocherens said.
The team conducted an isotopic analysis of the collagen from the bears' bones, finding that composition of individual amino acids in the collagen shows that the bears lived on a strictly vegan diet.
"Similar to today's giant panda (Ailuropoda melanoleuca), the cave bears were therefore extremely inflexible in regard to their food," Bocherens said, "We assume that this unbalanced diet, in combination with the reduced supply of plants during the last ice age, ultimately led to the cave bear's extinction."
The team next plans to examine additional cave bear bones from various European locations, as well as conduct controlled feeding experiments with modern bears, in order to further solidify their findings.
Results are published in the Journal of Quaternary Science.