Research overview: divergence between cave lions and modern lions

This overview examines genetic and fossil evidence bearing on when the cave lion lineage split from the ancestors of modern lions. Ancient DNA studies estimate that Panthera spelaea diverged from the line leading to living lions on the order of half a million years ago, after which the two lineages evolved independently with no clear evidence of interbreeding despite their ranges approaching one another. The survey reviews how molecular clocks calibrated with dated fossils produce these estimates, how the timing fits the broader history of Panthera, and what the lack of gene flow implies about reproductive or geographic separation. It discusses why establishing the cave lion as a long-distinct lineage, rather than a mere subspecies, has reshaped how researchers classify and interpret the great Ice Age lions.