The cave bear (Ursus spelaeus) is an extinct species which lived in Eurasia, where it appeared around 200,000 years ago. A descendant of Ursus deningeri, the cave bear owes its name to the discovery (in 1794) of its bones in an underground environment. Remains are particularly abundant in these environments as a result of its prolonged occupation of caves in the cold season. The wallows made by the bears enable us to identify the areas occupied during hibernation, and the trails of footprints to reconstruct their routes through the cave.
Larger and more solid than the brown bear, the cave bear can also be distinguished by a very steep forehead, which gave it a stepped profile, together with a jaw with a rounded lower edge and an upward facing nasal opening. These identifying elements are present in the specimens depicted in the Recess of the Bears, showing that the animal was attentively observed by Palaeolithic artists, who were also familiar with the brown bear, already present in Europe in the same period.
DNA analyses have been carried out on the bones of bears from all sectors of the cave and have made it possible to obtain the complete mitochondrial genome of the cave bear. The comparison of different specimens shows low genetic diversity, which is characteristic of a small population and a species threatened by extinction. The bones present on the cave floor make it possible to date the cave's latest occupations by bears. This appears to have been during the Aurignacian phase of the human use of the cave, 35,000 years ago.