Andean Leaf-Eared Mice Evolved to Live Above 6,700 Meters, Detoxifying Toxic Plants
Updated
Updated · ZME Science · Jul 17
Andean Leaf-Eared Mice Evolved to Live Above 6,700 Meters, Detoxifying Toxic Plants
2 articles · Updated · ZME Science · Jul 17
Summary
More than 160 Andean leaf-eared mice sampled from sea level to nearly 7,000 meters showed a suite of adaptations that let them survive year-round on volcanic summits once thought too extreme for mammals.
At 6,700 meters, where oxygen is about 44% of sea-level levels, the mice generate heat efficiently with oxygen-sparing muscles packed with mitochondria and a metabolism shifted toward fat burning.
Genome analyses found little evidence of major structural rewiring; instead, natural selection appears to have fine-tuned existing genes even though high- and low-altitude mice still interbreed.
The biggest surprise was food: researchers found selection in genes that break down toxic plant compounds, suggesting survival depends not just on hypoxia tolerance but also on exploiting sparse, chemically defended vegetation.
Published in Science, the study broadens high-altitude biology beyond oxygen transport and could inform research on chronic oxygen deprivation in diseases such as cancer.
Could the genes of high-altitude mice hold the secret to fighting oxygen-starved tumors in cancer patients?
As Andean mice conquer the world's highest peaks, what other life is hiding in Earth's most 'uninhabitable' places?
Life at 6,739 Meters: The Unprecedented Survival of the Andean Leaf-Eared Mouse and Its Implications for Biology and Medicine
Overview
In July 2026, scientists made a groundbreaking discovery by finding the Andean leaf-eared mouse (*Phyllotis vaccarum*) living at 6,739 meters on Volcán Llullaillaco—the highest altitude ever recorded for any mammal. This remarkable observation shattered previous records and challenged what was thought possible for mammalian survival at extreme elevations. Building on years of research into how animals adapt to low-oxygen, high-altitude environments, this finding redefined our understanding of how mammals can thrive in such harsh conditions. The discovery highlights the species’ broad elevational range and opens new directions for studying extreme survival in mammals.