This windblown debris, Steppan guesses, is probably their main source of food-but doesn’t seem very substantial. Why do the mice live at such a high elevation, where there is half the oxygen found at sea level? How do they survive in such conditions, where it also dips down to temperatures of -50 degrees Centigrade in the winter? And what do they eat?Īs for the last question, the climbers found almost no plant life that might provide sustenance, besides bits of lichen and plant chaff blown up from lower elevations. The comparison to Mars is also not a stretch: Schmidt and colleagues have been studying microbes here for years, which somehow survive in a soil whose surface can swing 125 degrees Fahrenheit in a single day-and these microorganisms help them understand how life might be able to survive on another less hospitable planets. The finding adds intrigue to Llullaillaco, which already has one of the highest-elevation lakes, the famous mummies, and unique microbes. “I was actually totally shocked that it was so precise.” “Each of the seven DNA fragments fell out in the exact place in the phylogeny,” Steppan says. It was an exact match with the yellow-rumped leaf-eared mouse. These researchers, including Steven Schmidt at the University of Colorado, Boulder, found another mouse that year, and collected a DNA sample from the soil outside the rodent’s hole. The pair sought out Steppan, an expert in Andean mice, and they collaborated with another team that climbed up Llullaillaco in 2016. “It struck me that this was probably a major finding,” Bowen says. In this case of the leaf-eared mice, these individuals are thought to be part of an established population.įarson wasn’t aware of the import of his sighting until he told Bowen. There have also been sightings of yaks and blue-sheep around 20,000 feet, but this is outside of their known habitable zone. Large-eared pikas, the previous record-holder, have been observed at 20,100 feet-more than 200 feet lower.

Yellow rumped leaf eared mouse