Cave bear teeth were very large and show greater wear than most modern bear species, suggesting a diet of tough materials.
However, tubers and other gritty food, which cause distinctive tooth wear in modern brown bears, do not appear to have constituted a major part of cave bears' diets on the basis of dental microwear analysis.

The morphological features of the cave bear chewing apparatus, including loss of premolars, have long been suggested to indicate their diets displayed a higher degree of herbivory than the Eurasian brown bear.
Indeed, a solely vegetarian diet has been inferred on the basis of tooth morphology.
Results obtained on the stable isotopes of cave bear bones also point to a largely vegetarian diet in having low levels of nitrogen-15 and carbon-13, which are accumulated at a faster rate by carnivores as opposed to herbivores.

However, some evidence points toward the occasional inclusion of animal protein in cave bear diets.
For example, toothmarks on cave bear remains in areas where cave bears are the only recorded potential carnivores suggests occasional cannibalistic scavenging, possibly on individuals that died during hibernation, and dental microwear analysis indicates the cave bear may have fed on a greater quantity of bone than its contemporary, the smaller Eurasian brown bear.
Additionally, cave bear remains from Peștera cu Oase in the southwestern tip of the Romanian part of the Carpathian Mountains had elevated levels of nitrogen-15 in their bones, indicative of omnivorous diets, although the values are within the range of those found for the strictly herbivorous mammoth.

Although the current prevailing opinion concludes that cave bears were largely herbivorous, and more so than any modern species of the genus Ursus, increasing evidence points to omnivorous diets, based both on regional variability of isotopic composition of bone remains indicative of dietary plasticity, and on a recent re-evaluation of craniodental morphology that places the cave bear squarely among omnivorous modern bear species with respect to its skull and tooth shapes.
Cave bear teeth were very large and show greater wear than most modern bear species, suggesting a diet of tough materials. However, tubers and other gritty food, which cause distinctive tooth wear in modern brown bears, do not appear to have constituted a major part of cave bears' diets on the basis of dental microwear analysis.
The morphological features of the cave bear chewing apparatus, including loss of premolars, have long been suggested to indicate their diets displayed a higher degree of herbivory than the Eurasian brown bear. Indeed, a solely vegetarian diet has been inferred on the basis of tooth morphology. Results obtained on the stable isotopes of cave bear bones also point to a largely vegetarian diet in having low levels of nitrogen-15 and carbon-13, which are accumulated at a faster rate by carnivores as opposed to herbivores.
However, some evidence points toward the occasional inclusion of animal protein in cave bear diets. For example, toothmarks on cave bear remains in areas where cave bears are the only recorded potential carnivores suggests occasional cannibalistic scavenging, possibly on individuals that died during hibernation, and dental microwear analysis indicates the cave bear may have fed on a greater quantity of bone than its contemporary, the smaller Eurasian brown bear. Additionally, cave bear remains from Peștera cu Oase in the southwestern tip of the Romanian part of the Carpathian Mountains had elevated levels of nitrogen-15 in their bones, indicative of omnivorous diets, although the values are within the range of those found for the strictly herbivorous mammoth.
Although the current prevailing opinion concludes that cave bears were largely herbivorous, and more so than any modern species of the genus Ursus, increasing evidence points to omnivorous diets, based both on regional variability of isotopic composition of bone remains indicative of dietary plasticity, and on a recent re-evaluation of craniodental morphology that places the cave bear squarely among omnivorous modern bear species with respect to its skull and tooth shapes.
Cave bear