Insights on the evolution and adaptation toward high-altitude and cold environments in the snow leopard lineage.

How snow leopard gradually adapted to the extreme environments in Tibet remains unexplored due to the scanty fossil record in Tibet. Here, we recognize five valid outside-Tibet records of the snow leopard lineage. Our results suggest that the snow leopard dispersed out of the Tibetan Plateau multiple times during the Quaternary. The osteological anatomy of the modern snow leopard shows adaptation to the steep slope and, to a lesser extent, cold/high-altitude environment. Fossils and phylogeny suggest that the snow leopard experienced a gradual strengthening of such adaptation, especially since the Middle Pleistocene (~0.8 million years). Species distribution modeling suggests that the locations of the fossil sites are not within most suitable area, and we argue that local landscape features are more influential factors than temperature and altitude alone. Our study underscores the importance of integrating morphology, fossil records, and species distribution modeling, to comprehensively understand the evolution, ecology, and inform conservation strategies for endangered species.