Effects of hibernation on the stable isotope signatures of adult and neonate cave bears


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Publication Date

January 2011


Stable isotope signatures (δ13C and δ15N) in bone collagen vary according to the metabolism, diet and environment of an animal, and are a valuable tool for paleoecological studies. In cave bears, the special metabolism during hibernation affects the pro-portion between light and heavy C and N isotopes in bone collagen. This effect is especially evident in neonates, whose tissue was formed during their mothers' hibernation, thus sharing the mother's δ13C y δ15N values during that period. By contrast, the values for adults represent the last years of life of the animal due to the slow turnover rate of the bone tissue. In this work we compare the δ13C and δ15N values in neonate and adult Ursus spelaeus from three caves of Galicia (Spain): Eirós, A Ceza and Liñares. The data obtained confirm that, even with differences in absolute values between the three populations, both in adults and neonates, hiberna-tion produces in all populations an increase in δ15N values, and more negative values on δ13C. This is consistent with the current knowledge of the metabolism of bears during hibernation, during which the animals do not eat, drink, defecate or urinate, and have to rely on fat storages and urea reuse in order to survive the winter dormancy.

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Quaternaire, Vol. 4 (2011).