From the paper Discovery of the world’s highest-dwelling mammal [1]
> Upper altitudinal limits of wild mammals in the Himalayas and Andes are generally thought to fall in the range 5200-5800 m above sea level. Such limits are surely dictated by food availability in addition to physiological capacities for tolerating hypoxia and extreme cold.
Which explains the significance of:
> we captured a specimen of the yellow-rumped leaf-eared mouse (Phyllotis xanthopygus rupestris) on the very summit of Llullaillaco at 6739 m
> Upper altitudinal limits of wild mammals in the Himalayas and Andes are generally thought to fall in the range 5200-5800 m above sea level. Such limits are surely dictated by food availability in addition to physiological capacities for tolerating hypoxia and extreme cold.
Which explains the significance of:
> we captured a specimen of the yellow-rumped leaf-eared mouse (Phyllotis xanthopygus rupestris) on the very summit of Llullaillaco at 6739 m
[1] https://www.biorxiv.org/content/10.1101/2020.03.13.989822v1