Isotopic evidence for omnivory among European cave bears: Late Pleistocene Ursus spelaeus from the Peştera cu Oase, Romania

Abstract

Previous bone collagen carbon and nitrogen isotopic studies of Late Pleistocene European cave bears (Ursus spelaeus) have shown that these bears frequently had low nitrogen isotope values, similar to those of herbivores and indicating either unusual physiology related to hibernation or a herbivorous diet. Isotopic analysis of animal bone from the Peştera cu Oase (Cave with Bones), Romania, shows that most of its cave bears had higher nitrogen isotope values than the associated herbivores and were, therefore, omnivorous. The Oase bears are securely identified as cave bears by both their morphology and DNA sequences. Although many cave bear populations may have behaved like herbivores, the Oase isotopic data demonstrate that cave bears were capable of altering their diets to become omnivores or even carnivores. These data therefore broaden the dietary profile of U. spelaeus and raise questions about the nature of the carnivore guild in Pleistocene Europe.

Fig. 1.

Left anterolateral views of Peştera cu Oase adult U. spelaeus crania. From top to bottom, N32.1 (female), O34.62b (female), N32.21 (male), and N37.49 (male). The protuberance on the N32.21 dorsal neurocranium is a stalagmite.

Fig. 2.

Isotope data for cave bears and other fauna from the Peştera cu Oase, Romania. Filled diamonds, U. spelaeus; open squares, C. lupus; filled triangles, C. elaphus; open triangles, C. ibex. S-EVA values are used except for the specimens for which only OxA data are available.

Fig. 3.

Distributions of δ¹⁵N values for U. spelaeus remains from European OIS 4–2 Late Pleistocene sites (Table 1) and the Peştera cu Oase (SI Table 2). Samples: Liñares (1), Eirós (2), southern France and Pyrenees (3), Chauvet (4), Scladina 1A (5), Divje Babe (6), eastern Alps (7), Muierii and Cioclovina (8), European (9), and Oase (10).