DIETARY ECOLOGY OF SMILODON ACROSS TIME AND SPACE

Climate change, including glacial cooling and interglacial warming, can influence dietary behavior, potentially affecting prey preferences and the degree of carcass utilization. In this study, we investigated the dietary behavior of Smilodon in Florida during the Pleistocene using dental microwear texture analysis (DMTA). We used DMTA metrics, complexity (Asfc) and anisotropy (epLsar), to capture their dietary habits in their final days to weeks before their death. Our research encompassed three main comparisons of DMTA metrics to assess the dietary hypothesis that Smilodon diets were consistent across space and time, including between glacial and interglacial sites in Smilodon gracilis, across time between species in Florida, and across space in Smilodon fatalis. First, we compared Florida’s glacial (Inglis 1A) and interglacial (Leisey Shell Pit 1A) sites of Smilodon gracilis, revealing a significant positive increase in epLsar values (p = 0.0321) during the glacial period, suggesting a shift to a tougher diet. Second, we conducted a temporal and species comparison from the early to late Pleistocene, during which S. gracilis was replaced by S. fatalis. This comparison revealed no differences between species, indicating niche conservation across time. Third, we performed a regional comparison of S. fatalis between Florida and previous DMTA data from Rancho La Brea, CA (RLB). This comparison revealed no difference in any DMTA variable, suggesting conservation of dietary behavior across space. While much of our understanding of Pleistocene carnivores in North America stems from Rancho La Brea, these data help provide a more comprehensive understanding of Smilodon dietary ecology across space and time. Specifically, our study clarifies Smilodon’s dietary habits in the ancient Floridian landscape, highlights the dietary adaptability and sensitivity of top predators to climate fluctuations, and demonstrates niche conservatism across space and time. These findings provide crucial insights into the adaptative strategies and ecological role of Smilodon in Florida during periods of significant environmental change.