摘要：SummaryThe saber-toothed catSmilodon fatalisis known predominantly from “predator trap” deposits, which has made many aspects of its life history difficult to infer. Here, we describe an association of at least two subadult and one adultS. fatalisfrom Pleistocene coastal deposits in Ecuador. The assemblage likely derived from a catastrophic mass mortality event, and thereby provides insights into the behavior of the species. The presence of a P3in the subadult dentaries suggests inheritance, a rare instance of familial relatedness in the fossil record. The siblings were at least two years old and were associated with an adult that was likely their mother, indicating prolonged parental care inS. fatalis. Comparison with the growth of pantherine cats suggests that S. fatalishad a unique growth strategy among big cats that combines a growth rate that is similar to a tiger and the extended growth period of a lion.Graphical AbstractDisplay OmittedHighlights•Association of two subadult and one adultSmilodon fatalisfrom Ecuador•Rare, likely genetic condition suggests subadults are siblings•S. fatalisappears to have exhibited fast growth over a prolonged period•Comparison with growth in lions and tigers suggests a unique growth strategyPaleontology; Ecology; Biological Sciences; Zoology; Evolutionary Biology; Evolutionary Ecology; Paleobiology
