https://phys.org/news/2018-07-extinct-vegetarian-cave-diet-mystery.html

However, a paper published in the journal Historical Biology, sheds new light on this. A research team from Germany and Spain found that Deninger's bear likely had a similar diet to its descendant—the classic cave bear—as new analysis shows a distinct morphology in the cranium, mandible and teeth, which has been related to its dietary specialization of a larger consumption of vegetal matter.

To understand the evolution of the cave bear lineage, the researchers micro-CT scanned the rare fossils and digitally removed the sediments so as not to risk damaging the fossils. Using sophisticated statistical methods, called geometric morphometrics, the researchers compared the three-dimensional shape of the mandibles and skull of Deninger's bear with that of classic cave bears and modern bears.