The highest dwelling mammal – a mouse – has been discovered at 6700 metres above sea level, where conditions are so harsh they have been compared to Mars
Source:
https://www.newscientist.com/article/2237997-worlds-highest-mammal-discovered-at-the-top-of-a-mars-like-volcano/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home