The mice found at the Yuyaco volcano are known as the tallest mammals in the world.

The world’s tallest dormant volcano is not as desolate as scientists once thought,media CNET reported. Earlier this year, during a mountaineering expedition in northern Chile, researchers found and captured a yellow-backed leaf ear rat on the top of the 22,000-foot (6,705.6-meter) mountain top of the Yuyeaco volcano. The mouse broke the world record for the altitude of a mammal’s habitat set by scientists to date. Last year, the same species of rat was found at 20,340 feet.

The mice found at the Yuyaco volcano are known as the tallest mammals in the world.

In a study published Thursday in the Proceedings of the National Academy of Sciences, researchers from universities in the United States and Chile documented their rodent findings and explained that this could help scientists better understand how mammals adapt and survive harsh conditions at high altitudes.

“This finding suggests that we may be generally underestimating the altitude limits and physiological tolerance of small mammals, simply because some of the world’s highest peaks are still relatively unexploited places for biologists,” the study said.

The mice found at the Yuyaco volcano are known as the tallest mammals in the world.

Phyllotis xanthopygus rupestris lives high in the Andes, but also at sea level, making it an interesting mammal studied by scientists. “The scope is extraordinary,” Scott Steppan, a professor of biology at Florida State University, told National Geographic. “No other species can do that.”

Jay Storz, a biologist at the University of Nebraska, led a recent expedition to find the yellow-backed leaf-eared rat at the highest point. Although Storz and his team set up small traps to catch the rodents for research, when he found the mouse scurrying under a rock, he actually grabbed it by hand on a 22,000-foot hilltop.

“One of the worst conditions on Earth — some say, is the closest thing to Mars on our planet — these mice not only survived, but apparently thrived,” Steppan said in a statement. “This amazing altitude shows what extreme life can reach.”

Mario Perez-Mamani, a professional mountaineer who accompanied Storz on the expedition, captured the mouse trap in video. The yellow-backed leaf ear rat is not the only record-breaking rodent found on the Storz expedition. He also previously found a Phyllotis limatus at 16,633 feet, well above the highest altitude recorded in the species’ known habitat.