Temperature plays a key role in the biology of ectotherms, including anurans, which are found at higher elevations in the tropics than anywhere in the temperate zone. High-elevation tropical environments are characterized by extreme daily thermal fluctuation including high daily maxima and nightly freezing. Our study investigated the contrasting operative temperatures of the anurans Telmatobius marmoratus and Pleurodema marmoratum in different environmental contexts at the same elevation and biome above 5200 meters. Telmatobius marmoratus avoids...