Mice thrive at 6700 meters up —higher than any mammals were thought able to live

Few places are as inhospitable as the top of Llullaillaco, a 6700-meter volcano on the border between Chile and Argentina. Winds howl nonstop and no plants live there; daytime temperatures never get above freezing and plummet even more come nightfall. Oxygen levels are just 40% of those at sea level, too low for mammals to live there —or so biologists thought until 3 years ago when a research team captured a live leaf-eared mouse at its summit. Now new work shows this animal was not a fluke. The team has found other leaf-eared mice on additional volcano tops, and genomic studies of these summit dwellers and their lower elevation relatives confirm the rodents make their homes nearly 7000 meters above sea level, making them the highest dwelling vertebrate found so far. (Some birds soar higher but appear not to dwell at those elevations.) The team has also come across five other mouse species living above 5000 meters on various mountains in the Central Andes. The genomic results and other evidence reported today in Current Biology “lay to rest any doubt that mammals live at these really extreme altitudes,” says Grant Mcclelland,  a comparative physiologist at McMaster University who was not involved with the work. “It expands our understanding of the environmental limits of animals, especially mammals.” The cold temperatures and low oxygen associated with high altitudes have long been thought to set a limit on the heights where cold-blo...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research