Mouse hanging out atop volcano called world’s highest-dwelling mammal – CNET [CNET]

The world’s highest summits aren’t as desolate as scientists once thought. During a mountaineering expedition in northern Chile earlier this year, researchers spotted and captured a yellow-rumped leaf-eared mouse atop the 22,000-foot summit of Volcan Llullaillaco.

The mouse broke the world record for the highest-dwelling mammal documented by scientists to date. Last year, the same species of mouse was spotted at 20,340 feet. 

In a study published Thursday in the journal Proceedings of the National Academy of Sciences, university researchers from the US and Chile document their rodent discovery and explain that it could help scientists better understand how mammals adapt to and survive harsh conditions at high altitudes.

“The discovery suggests we may have generally underestimated the altitudinal range limits and physiological tolerances of small mammals simply because the world’s highest summits remain relatively unexplored by biologists,” the study says.

The yellow-rumped leaf-eared mouse (Phyllotis xanthopygus rupestris) dwells high in the Andes mountains but also lives at sea level, which makes it an interesting mammal for scientists to study. 

“That wide of a range is extraordinary,” Florida State University biology professor Scott Steppan told National Geographic. “No other species does that.”

University of Nebraska biologist Jay Storz led the recent expedition that found the yellow-rumped leaf-eared mouse at the highest point. Even though Storz and his team set small traps to capture rodents for study, he actually caught the mouse atop of the 22,000-foot summit by hand when he spotted it scurrying under a rock.

“In one of the harshest environments on Earth — considered by some as the closest thing on our planet to Mars — these mice not only survive but apparently thrive,” Steppan said in a statement. “This astonishing elevation shows to what extremes life is capable of.”

Professional mountaineer Mario Perez-Mamani, who accompanied Storz on the expedition, captured the mouse-catching moment on video.

The yellow-rumped leaf-eared mouse wasn’t the only rodent breaking records on Storz’s expedition. He also found a Lima leaf-eared mouse (Phyllotis limatus) at 16,633 feet. That surpassed previous altitude-dwelling records for this species.