Mortality patterns and skeletal physical condition of the carnivorans from the Miocene assemblage of Batallones-1 (Madrid Basin, Spain)

Batallones-1 lower level assemblage contains numerous and diverse Miocene vertebrates that were deposited over time at the bottom part of a cavity. In this study, the age structure and skeletal physical condition of the four more abundant taxa, all of them carnivorans, are analysed to better delineate the taphonomic history undergone by the remains and the concentration mode of the assemblage. The prime-adult dominated profile of the two sabertoothed cats and the hyaenid can be related to a proneness of these individuals to search for resources in dangerous locations during the stressful period of dispersal. In turn, the amphicyonid profile, where juveniles are abundant, can be the result of the entrance in the cave of mothers with cubs. The demography of the analysed taxa has allowed to discard in Batallones-1 LLA mass, attritional or accidental death modes. Rather, the entrance of animals in the cavity was intentional and resulted in the entrapment of the individuals. Besides, the animals represented in Batallones-1 LLA do not show signals of poor physical condition as revealed by the comparison of the frequency of osteopathologies and broken canines in life of the extinct taxa with modern healthy counterparts. Consequently, incidence of injuries in the skeleton of these individuals can be discarded as a major cause of entrapment.This study was funded by the Spanish Government Ministry of Science and Innovation research projects CGL2008-05813-C02-01/BTE, CGL2007-60790/BTE, and CGL2010-19116/BOS and is included in the CAM-UCM 910607 Research Group. MSD was supported by the Fundación Española para la Ciencia y la Tecnología (FECYT) and the Spanish Ministry of Education Postdoctoral Fellowship Programme.N