Cave bear molars are wide and low-crowned with complex grinding surfaces, and the shearing carnassial blade found in meat-eating carnivorans is reduced. Microscopic wear patterns on the enamel match the abrasion of tough plant material. Stable nitrogen isotope ratios measured in cave bear bone collagen typically sit at values expected of a herbivore rather than a predator.
The bones themselves accumulated through ordinary hibernation mortality. A cave used across many millennia collects the remains of animals that entered to overwinter and did not wake, which is why some sites contain thousands of individuals without any implication of mass death or of ritual by humans.
Most dates place the extinction around twenty-four thousand years ago, near the last glacial maximum. A plant-based diet requiring reliable seasonal vegetation and long cave hibernation offers little flexibility when growing seasons shorten, and competition with humans for cave sites has also been proposed. Brown bears, which are omnivorous and less dependent on caves, came through the same period.