Acta Zoologica Cracoviensia, 60(2) 2017
Issue:
VOL 60(2) 2017
DOI:
10.3409/azc.60_2.01
Keywords:
14C dating, cave bear, extinction, Last Glacial Maximum, megafauna, Pleisto-cene, radiocarbon dates, Ursus spelaeus, Ursus ingressus
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Estimating the extinction time of two cave bears, Ursus spelaeus and U. ingressus
Abstract:
Although cave bear remains have been described since the end of 18th century, recent discoveries and methods provide new knowledge about the typical representative of Pleistocene megafauna, which did not survive the Last Glacial Maximum. Genetic studies supplemented by morphometric analyses showed that this mammal differentiated in the Late Pleistocene into two main forms called Ursus spelaeus and U. ingressus. The latter is regarded more expansive and replaced the native U. spelaeus in some areas of Western Europe. Taking into account the differences between these bears, it is interesting to determine if these forms became extinct at different or similar times. Therefore, we assessed their extinction times, applying seven methods using 205 dated records of cave bear ascribed to these two forms. The average extinction time of U. spelaeus was about 25,600 cal. yr BP (Before Present) and of U. ingressus about 24,800 cal. yr BP. The estimations showed that that U. ingressus could survive up to ca. 1,000 years longer than its relative U. spelaeus. The longer survival of the former could be related to its greater morphological variability and better adaptation to arid continental environments, as well as a stronger tendency to occasional omnivory. Both bears became extinct within the coldest phase of the last glacial period, Greenland Stadial 3, which implies that climate cooling was the main factor of their extinction. The climate deterioration decreased vegetation productivity, and could also have had negative consequences on the prolonged hibernation period when the bears were more susceptible to the activity of humans and predators.
