European Cave Bears

Had Pure Herbivorous Diet

An isotopic analysis of fossil collagen from the bones collected in three Romanian caves indicates that the cave bear (Ursus spelaeus), an extinct species of bear that lived 300,000-25,000 years ago in Europe, the Mediterranean and Asia, was exclusively herbivorous.

Reconstruction of the cave bear (Ursus spelaeus). Image credit: Sergio de la Larosa / CC BY-SA 3.0.

The cave bear was a very large type of bear that formed the sister lineage of living brown bears and polar bears.

The animal lived during the Pleistocene epoch and became extinct approximately 25,000 years ago.

It was 2.7-3.5 m (8.9-11.5 feet) long and up to 1.7 m (5.6 feet) at the shoulder, and has a mass between 225 and 500 kg.

Dietary habits of the cave bear has widely been debated as different paleobiological studies produced different dietary inferences for the animal, ranging from carnivory to pure herbivory.

“It comes as big surprise that these animals — despite their size and the fact they lived in a cold and dry environment — exclusively subsisted on plants,” said senior author Professor Herve Bocherens, a researcher in the Senckenberg Center for Human Evolution and Palaeoenvironment and the Department of Geosciences, Biogeology at the University of Tübingen.

“While this vegetarian lifestyle has already been proven for the vast majority of cave bears in Europe, fossil discoveries from Romania gave rise to a lively scientific discussion as to whether cave bears in that region may also have fed on meat.”

For the study, Professor Bocherens and colleagues used 20,000 to 49,000-year-old skeletal remains of six adult cave bears from the three Romanian cave sites: Măgura, Cioclovina and Răsuflătoarei.

“Well-preserved bone specimens of cave bears from these three sites allowed us to examine the feeding behavior of the individuals from this region,” the researchers said.

They analyzed the nitrogen isotope values of amino acids in the bone collagen from the cave bear specimens.

“We measured special amino acids in the fossil bone collagen and subsequently compared the values with those from other cave bear bones as well as typical carnivores and herbivores; in our case, a lion and a horse,” Professor Bocherens added.

“Our results show that Romanian cave bears subsisted on an exclusively vegetarian diet before they became extinct about 25,000 years ago.”

The study was published in the journal Scientific Reports.

_____

Y.I. Naito et al. Heavy reliance on plants for Romanian cave bears evidenced by amino acid nitrogen isotope analysis. Sci Rep 10, 6612; doi: 10.1038/s41598-020-62990-0