Research overview: stable isotope methods for reconstructing fossil felid diet

This overview surveys the stable isotope techniques used to reconstruct the diets of extinct cats. Carbon isotopes in bone and tooth collagen and enamel record whether prey fed on plants using different photosynthetic pathways, distinguishing grassland from woodland food webs, while nitrogen isotopes track trophic level and indicate how high a predator sat in its ecosystem. The survey reviews how researchers sample and purify collagen, account for contamination and diagenesis, and interpret isotopic values relative to contemporary prey, as applied to Smilodon, cave lions, and other fossil felids. It discusses the strengths and limitations of these proxies, how they convert questions about ancient diet into quantitative measurements, and why isotope geochemistry has become a cornerstone method for studying the feeding ecology of vanished predators.