Ancient ancestors of other Bear species, cave bears were massive, stocky mammals that once roamed forested valleys and rocky highlands. They had broad skulls, strong jaws, and thick, coarse fur that varied from brown to dark gray. Adults were even larger than Polar Bear males, with large, powerful limbs ended in heavy claws suited for digging and climbing.
Cave bears were primarily herbivorous, feeding on roots, berries, nuts, and other vegetation, though some individuals may have supplemented their diet with small animals or carrion. They were largely solitary, though they sometimes gathered near abundant food sources. As their name implied, they used caves for shelter and hibernation, often leaving deep scratch marks and dens filled with the remains of their meals.
During hibernation, cave bears would retreat into these dens for months at a time, subsisting on stored fat. Mothers gave birth in the safety of the cave, nursing one to three cubs until they were strong enough to leave. Though usually non-aggressive, cave bears could become formidable if threatened or if cubs were nearby.