Research overview: the American lion and Panthera evolution in the New World

The American lion, Panthera atrox, was one of the largest cats ever to live, roaming Pleistocene North America south of the ice sheets. This overview surveys ancient-DNA evidence indicating that the American lion was closely allied to the Eurasian cave lion lineage, having entered North America and become isolated south of the continental glaciers, where it diverged into a giant form. It discusses the relationships among cave lions, American lions, and modern lions, the debate over whether atrox was a lion or a distinct species, and how genetic data on these extinct giants refine the broader picture of Panthera dispersal across continents.