Watch: Tiny mouse is world’s highest-dwelling mammal

The yellow-rumped leaf-eared mouse is a tiny mammal, but it stands over 22,000 feet tall. Recently found at the summit of Volcán Llullaillaco, a dormant volcano on the border of Chile and Argentina, the mouse (Phyllotis xanthopygus rupestris) has earned the title of the highest-dwelling mammal in the world. The discovery knocks the large-eared pika (Ochotona macrotis) down a notch. It was found at over 20,000 during a 1921 Mount Everest expedition.

The species claims one other record. It has the broadest altitude distribution of any known mammal, ranging all the way down to sea level.

Jay Storz, an evolutionary biologist at the University of Nebraska–Lincoln, and mountaineer Mario Pérez Mamani discovered the animal at the volcano’s summit. After collecting several mice from the same and different species, Storz and his team plan to look for genetic changes that allow them to deal with the high elevations.

“It’s very difficult to sustain any kind of physical activity, or mental activity for that matter,” Storz told Science News.

Read more from Science News here, and watch the video below.

Header Image: A yellow-rumped leaf-eared mouse similar to this one was found at the summit of Volcán Llullaillaco.
Credit: Marcial Quiroga-Carmona