This photograph shows a member of the research team at the summit of Ojos del Salado, 6,893 m (Puna de Atacama, Chile-Argentina). Credit: Mario Pérez Mamani.
Key points:
- Researchers were surprised to find mummified mice at the summit of volcanoes in Chile, over 6,000 meters above sea level.
- They were even more surprised when analysis showed the mice traveled up there by themselves to live, rather than hitching a ride with humans.
- The team is now looking into how a warm-blooded mammal can survive the tough, Martian-like environment at the volcano summits.
The summits of volcanoes in the Puna de Atacama of Chile and Argentina are the closest thing on Earth to the surface of Mars due to their thin atmosphere and freezing temperatures. At their extreme elevations of over 6,000 meters above sea level, experts had originally concluded that mammalian life simply wasn’t possible. Now, a team of researchers and mountaineers from the University of Nebraska–Lincoln show that’s not necessarily true.
In a new study in Current Biology, researchers detail their discovery of mummified mice at the apex of the volcanoes, thus expanding the limits of vertebrate life on Earth.
Senior author Jay Storz, a biologist at University of Nebraska, Lincoln, and his colleagues discovered the first mouse mummy on the summit of Volcán Salín by chance when they stumbled across the desiccated cadaver at the edge of a rock pile. Then, they went looking for more.
Searching 21 volcano summits, the mountaineers have found 13 mummified mice on volcano summits with an elevation greater than 6,000 meters. In some cases, the mummies were accompanied by skeletal remains of numerous other mice.
Radiocarbon dating showed that the mummified mice found on the summits of two volcanoes were a few decades old at most. Those from a third site were older, estimated at about 350-years-old. Genetic analysis of the summit mummies demonstrated that they represent a species of leaf-eared mouse called Phyllotis vaccarum, which is known to occur at lower elevations in the region.
Initially, the researchers thought the rodents hitched a ride with the Incas, who once pilgrimaged a thousand-plus miles to what they considered sacred sites. However, even 350 years ago is a full century after the last of the Incan empire fell.
“It now seems more and more clear, that the mice got there of their own accord,” Storz said. “It just boggles the mind that any kind of animal, let alone a warm-blooded mammal, could be surviving and functioning in that environment.”