The cave bear (Ursus spelaeus sensu lato) is a typical representative of Pleistocene
megafauna which became extinct at the end of the Last Glacial. Detailed knowledge
of cave bear extinction could explain this spectacular ecological transformation.
The paper provides a report on the youngest remains of the cave bear dated to 20,930
+/- 140 C-14 years before present (BP). Ancient DNA analyses proved its affiliation
to the Ursus ingressus haplotype. Using this record and 205 other dates, we determined,
following eight approaches, the extinction time of this mammal at 26,100-24,300 cal.
years BP. The time is only slightly earlier, i.e. 27,000-26,100 cal. years BP, when
young dates without associated collagen data are excluded. The demise of cave bear
falls within the coldest phase of the last glacial period, Greenland Stadial 3. This
finding and the significant decrease in the cave bear records with cooling indicate
that the drastic climatic changes were responsible for its extinction. Climate deterioration
lowered vegetation productivity, on which the cave bear strongly depended as a strict
herbivore. The distribution of the last cave bear records in Europe suggests that
this animal was vanishing by fragmentation into subpopulations occupying small habitats.
One of them was the Krakow-Czestochowa Upland in Poland, where we discovered the latest
record of the cave bear and also two other, younger than 25,000 C-14 years BP. The
relatively long survival of this bear in karst regions may result from suitable microclimate
and continuous access to water provided by deep aquifers, indicating a refugial role
of such regions in the Pleistocene for many species.