RT Journal Article SR Electronic T1 Computed tomography reveals hip dysplasia in the extinct Pleistocene saber-tooth cat Smilodon JF bioRxiv FD Cold Spring Harbor Laboratory SP 2020.01.07.897348 DO 10.1101/2020.01.07.897348 A1 Balisi, Mairin A. A1 Sharma, Abhinav K. A1 Howard, Carrie M. A1 Shaw, Christopher A. A1 Klapper, Robert A1 Lindsey, Emily L. YR 2021 UL http://biorxiv.org/content/early/2021/06/26/2020.01.07.897348.abstract AB Reconstructing the behavior of extinct species is challenging, particularly for those with no living analogues. However, damage preserved as paleopathologies on bone can record how an animal moved in life, potentially reflecting behavioral patterns. Here, we assess hypothesized etiologies of pathology in a pelvis and associated right femur of a Smilodon fatalis saber-toothed cat, one of the best-studied species from the Pleistocene-age Rancho La Brea asphalt seeps, California, USA, using visualization by computed tomography (CT). The pelvis exhibits massive destruction of the right hip socket that was interpreted, for nearly a century, to have developed from trauma and infection. CT imaging reveals instead that the pathological distortions characterize chronic remodeling that began at birth and led to degeneration of the joint over the animal’s life. These results suggest that this individual suffered from hip dysplasia, a congenital condition common in domestic dogs and cats. This individual reached adulthood but could not have hunted properly nor defended territory on its own, likely relying on a social group for feeding and protection. While extant social felids are rare, these fossils and others with similar pathologies are consistent with a spectrum of social strategies in Smilodon supported by a predominance of previous studies.Competing Interest StatementThe authors have declared no competing interest.