Diet reconstruction in cave bears from craniodental morphology: past evidences, new results and future directions

ABSTRACT

The diet of the cave bear (Ursus spelaeus) is a controversial topic, as different paleobiological approaches (e.g. dental wear, isotopic biochemistry, skull morphometrics) result in different dietary inferences for the cave bear, ranging from carnivory to pure herbivory. Here, we review the main results obtained from these approaches, with special emphasis on those obtained from the morphometric analyses of the cave bear craniodental skeleton. Then, we compute a between-group Principal Components Analysis from a set of 3D-landmarks digitized on 103 mandibles of living bears and extinct cave bears and using a phylomorphospace approach. Moreover, we also reconstructed the evolutionary trajectory of the cave bear mandible from the hypothetical shape of its inferred ancestor. Our results indicate that the mandible of the cave bear possess specific traits indicative of a highly-herbivorous diet or, at least, more herbivorous than their closest living relative, the brown bear (Ursus arctos). Moreover, we also propose new directions for future research to obtain more detailed inferences on the potential food resources consumed by the cave bear being crucial to understand the ‘life and death’ of this vanished animal.

KEYWORDS:

• Dietary inferences
• cave bear
• craniodental morphology
• geometric morphometrics

Acknowledgements

We are grateful to Alejandro Pérez-Ramos for helping with the edition of Figure 1. The comments of two anonymous reviewers helped to improve the clarity and rigor of the manuscript and are greatly appreciated.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Ministerio de Ciencia e Innovación [CGL2012-37866; CGL2015-68300P].