When thinking of the Pleistocene epoch, terrifying megafauna probably come to mind. Cave lions, dire wolves, saber-toothed cats and cave bears are just some of the monstrous beasts that walked the Earth during the last ice age but which are now extinct. But one of these creatures was not like the others.

It turns out that cave bears (Ursus spelaeus), some of the largest bears to ever roam Europe, were vegetarians, reports Phys.org. It's not usually how we think of bears — save for the cuddly panda — but this was one clawed behemoth that wouldn't have had humans on the menu.

Researchers have long suspected that cave bears were at least predominantly vegetarian due to their dentition. While these bears had huge teeth, those teeth appear to have been better suited for grinding than slashing. A new study analyzing the dentition of the cave bear's evolutionary ancestry, however, might just have settled it.

The teeth tell the story

A research team from Germany and Spain looked closely at known remains of teeth from the so-called Deninger's bear, a direct ancestor of the cave bear. The new analysis used sophisticated statistical methods, called geometric morphometrics, to compare the shapes of the mandibles and skulls of both bears.

"The analyses showed that Deninger's bear had very similarly shaped mandibles and skull to the classic cave bear," explained Anneke van Heteren, lead-author of the study.

So at the very least, Deninger's bear would already have been adapted to a vegetarian diet before the cave bear descended from them.

"There is an ongoing discussion on the extent to which the classic cave bear was a vegetarian. And, this is especially why the new information on the diet of its direct ancestor is so important, because it teaches us that a differentiation between the diet of cave bears and brown bears was already established by 500 thousand years ago and likely earlier," explained Mikel Arlegi, co-author of the study.

Of course, you still probably wouldn't have wanted to wander into a cave where a cave bear was nesting. While they may have preferred fruits and nuts to flesh and bones, they would have been more than capable of defending themselves. Even so, it's comforting to think that the world of the Pleistocene had at least one less gigantic predator in it, and one more gentle giant.

One of the largest bears to ever walk Europe was a vegetarian
The extinct cave bear Ursus spelaeus appears to have descended from a vegetarian line of bears.