The world’s highest-dwelling mammal
You may have experienced shortness of breath on a visit to some mountainous place. This is because there is less oxygen at high altitudes. Recently, a yellow-rumped leaf-eared mouse, Phyllotis xanthopygus rupestris, was found at 6,739 meters above sea level on the summit of Volcán Llullaillaco, a dormant volcano on the border of Chile and Argentina in South America. For comparison, Mount Everest is 8,848 meters high.
It is very surprising that mammals can live at such high altitudes, since there is only about 44 percent of the oxygen available at sea level. It is difficult to sustain any kind of physical activity, or even mental activity, in a place where temperature is rarely above freezing and can drop as low as –60° Celsius.
From Sciencenews.org