Saber-toothed cats: Horrifying genetic defects revealed

A study published in Frontiers in Veterinary Science has documented an extraordinarily high burden of congenital spinal defects and nerve tumors in the saber-toothed cat Smilodon fatalis, evidence the authors argue points to severe inbreeding in the final millennia before the species vanished. The analysis examined more than 3,700 vertebrae recovered from the La Brea tar pits in Los Angeles, representing at least 849 individual cats that lived roughly 12,000 years ago. Tar pits as a pathological archive The La Brea asphalt seeps functioned as a natural trap: herbivores mired in the viscous bitumen attracted predators, which then became stuck themselves. This process accumulated thousands of skeletons in stratigraphic layers that span the end of the Pleistocene. For the current study, researchers used computed tomography to scan vertebrae from the collection, screening for developmental anomalies, degenerative changes, and neoplastic growths. Pathology type Cases identified Congenital vertebral defects More than 200 Fused vertebrae Nearly 50 Spinal nerve tumors (SNT) 3 confirmed Tumor frequency far exceeds modern benchmarks The three confirmed spinal nerve tumors translate to an estimated incidence of 353 cases per 100,000 individuals. For comparison, the reported incidence of comparable nerve-sheath tumors in humans is 0.38 per 100,000. The congenital defects — malformed, fused, or asymmetrical vertebrae — were distributed across the sample in numbers that the researchers say cannot be explained by random injury or post-mortem distortion.