High‑altitude mouse found near 7,000 meters may redefine mammal survival limits

Key Points:

• Researchers discovered leaf-eared mice living at nearly 7,000 meters in the Andes, surpassing the previously believed mammalian altitude limit of 5,500 meters, challenging assumptions about life in extreme environments.
• The mice survive harsh conditions—freezing temperatures, low oxygen, scarce water, and limited plant life—through a combination of physiological adaptations, including enhanced heat retention and oxygen use, with muscle tissue resembling that of endurance athletes.
• These high-altitude mice rely heavily on fats for energy and have evolved genetic changes enabling them to metabolize unusual, scarce food sources like lichens and detoxify harmful plant compounds.
• The study highlights evolution as a complex, multilayered process where multiple bodily systems adapt simultaneously to environmental pressures, expanding understanding of life's limits on Earth.
• Findings emphasize that animals face multiple simultaneous challenges beyond temperature, suggesting evolutionary responses may be more diverse and unpredictable, with implications for species adapting to climate change.