First report of a South American short-faced bears' den (Arctotherium angustidens): palaeobiological and palaeoecological implications

Abstract

Here we report the first example of associated short-faced bear fossils from South America. The specimens represent three individuals referable to the Ensenadan (early to middle Pleistocene) species Arctotherium angustidens (Ursidae, Tremarctinae), the giant South American short-faced bear. Although the fossil record of short-faced bears in South America is very rich, they have not previously been recorded in association. These three individuals were found in a cave during quarry exploitation. We suggest that these bears represent the first record of a family group and open the discussion about cave utilization and hibernation or torpor by South American short-faced bears.

Key words:

• South America
• short-faced bear
• Arctotherium
• Tremarctinae
• Pleistocene

Acknowledgements

We thank Stephen McLoughlin, Blaine Schubert, Claudia Montalvo, Francisco Prevosti and Marcos Cenizo for valuable and useful suggestions on an early version of this manuscript, and Susana Bargo and Sergio Vizcaino for discussion on cave utilization by fossil xenarthrans. The authors also thank CONICET, CIC-PBA; ANPCyT PICT 38171; and the Secretaría de Ciencia y Técnica de la UNLP for financial support.