Andean leaf-eared mouse survives at 22,000 feet, study reveals metabolic adaptations

A study published July 9 in Science reveals how the Andean leaf-eared mouse (Phyllotis xanthopygus) survives at 22,000 feet on Llullaillaco volcano, the highest elevation for any mammal. Researchers captured 167 mice from high and low elevations in the Central Andes (2020–2023) and tested their responses to cold, low-oxygen conditions. Highland mice showed greater oxygen absorption, transport, and use, with more mitochondria and a reliance on fats rather than carbohydrates for heat generation. Genetic changes related to metabolism and detoxification of toxic plants were identified. The species also has the broadest elevational range of any mammal, living from sea level to volcano summits. Mummified remains found on three Andean volcanoes suggest routine high-altitude habitation. Co-authors include Grant McClelland (McMaster University), Naim Bautista (University of Oklahoma), and Jay Storz (University of Nebraska–Lincoln). The findings may inform treatments for human cardiovascular diseases.