Researchers found a yellow-rumped leaf-eared mouse (Phyllotis xanthopygus rupestris) at a record altitude of 6,739 meters, or 22,100 feet, above sea level. This mouse is living on the summit of Volcán Llullaillaco, a dormant volcano on the border of Chile and Argentina. It becomes the world record holder as the highest-dwelling mammal yet documented.
The record was previously held by the large-eared pika (Ochotona macrotis), reported at an altitude of 6,130 meters during a 1921 Mount Everest expedition. Though few birds can fly at even higher altitudes. But the body of a mammal is much more different than avian species. Here is the video of the miraculous mouse.
Jay Storz, an evolutionary biologist at the University of Nebraska–Lincoln, and mountaineer Mario Pérez Mamani discovered the animal at the summit of Volcán Llullaillaco, a dormant volcano on the border of Chile and Argentina. In this place there is only about 44 percent of the oxygen available compared to sea level and temperature is also rarely above freezing and can drop as low as -60° Celsius. Storz said,
It is very difficult to sustain any kind of physical activity, or mental activity for that matter.
Storz and colleagues captured several yellow-rumped leaf-eared mice, including this record breaker. The team reports this capture on July 16 in proceedings of the National Academy of Sciences. The team plans to look for genetic changes that might have equipped these animals to survive at high elevations. Surprisingly, another yellow-rumped leaf-eared mouse was found at sea level, indicating that this species has the broadest altitude distribution of any mammal, in addition to the altitude record.
Graham Scott, a physiologist at McMaster University in Hamilton, Canada said,
It's so amazing that they're up there. Understanding how these and other animals survive under low-oxygen conditions could provide insight into how humans could overcome diseases that cause reduced oxygen levels.