Andean Leaf-Eared Mouse Thrives in Toxic Volcanic Soil at Extreme Altitudes

Surviving at extreme altitudes is already a considerable challenge for most mammals, let alone in an environment that harbors other equally deadly threats. The Andean leaf-eared mouse (Phyllotis vaccarum) not only manages to live at the summit of volcanoes nearly 7,000 meters high, where temperatures are almost always below freezing and oxygen is extremely scarce, but it also must contend with toxins present in the volcanic soil and the surrounding vegetation. A study published in the journal Science on July 9, 2026, reveals how this small mammal has become one of the most tenacious creatures in the world, with the widest distribution range from sea level to the peaks of the Andes. The population of Andean leaf-eared mice living on the summit of Llullaillaco volcano, on the border of Argentina and Chile, endures at an altitude of 6,739 meters, where the air pressure is only 45 kilopascals, equivalent to about 44 percent of the oxygen available at sea level. The research, led by Schuyler Liphardt along with a team from the University of Nebraska-Lincoln and several other institutions, combines physiological experiments with genomic analysis to understand the adaptive mechanisms of the Andean leaf-eared mouse. Before this discovery, such altitudes were believed to be beyond the survival capabilities of any mammal; even highly trained and acclimatized human climbers can only withstand such low oxygen levels for a single day's ascent, not for permanent habitation. Efficient Body Heat Production The research team tested the breathing and body heat production capabilities of mice from populations residing at these extreme heights. This study sheds light on the physiological adaptations that allow these small mammals to thrive in an environment previously considered uninhabitable for their kind.