biostudies-literatureUnknown18(7)Schmokel HSkeletal disease may hamper the behavior of large predators both living and extinct. We investigated the prevalence of osteochondrosis dissecans (OCD), a developmental bone disease affecting the joints, in two Ice Age predators: the saber-toothed cat Smilodon fatalis and dire wolf Aenocyon dirus. As published cases in modern Felidae and wild Canidae are rare, we predicted that subchondral defects resembling OCD would be rare in the extinct predators. We examined limb joints in juvenile and adult S. fatalis: 88 proximal humeri (shoulder), 834 distal femora (stifle), and 214 proximal tibiae. We also examined limb joints in juvenile and adult A. dirus: 242 proximal humeri, 266 distal femora, and 170 proximal tibiae. All specimens are from the Late Pleistocene Rancho La Brea fossil locality inPloS onee0287656https://www.ebi.ac.uk/biostudies/studies/S-EPMC10337945biostudies-literatureSubchondral defects resembling osteochondrosis dissecans in joint surfaces of the extinct saber-toothed cat Smilodon fatalis and dire wolf Aenocyon dirus.PMC10337945Farrell ASchmokel HBalisi MFfalseSubchondral defects resembling osteochondrosis dissecans in joint surfaces of the extinct saber-toothed cat Smilodon fatalis and dire wolf Aenocyon dirus.Skeletal disease may hamper the behavior of large predators both living and extinct. We investigated the prevalence of osteochondrosis dissecans (OCD), a developmental bone disease affecting the joints, in two Ice Age predators: the saber-toothed cat Smilodon fatalis and dire wolf Aenocyon dirus. As published cases in modern Felidae and wild Canidae are rare, we predicted that subchondral defects resembling OCD would be rare in the extinct predators. We examined limb joints in juvenile and adult S. fatalis: 88 proximal humeri (shoulder), 834 distal femora (stifle), and 214 proximal tibiae. We also examined limb joints in juvenile and adult A. dirus: 242 proximal humeri, 266 distal femora, and 170 proximal tibiae. All specimens are from the Late Pleistocene Rancho La Brea fossil locality in2023-01-01T00:00:00Z20232026-05-09T14:03:08.2Z2025-04-22T21:11:24.383ZS-EPMC103379453743696710.1371/journal.pone.0287656