The snake Chironius monticola inhabits cloud forests at elevations of 3,300 to 10,500 feet (1,000 to 3,200 meters) in southern Peru's Manú National Park, on the western side of the Amazon Basin.

"Only a few snake species can live above 3,000 meters [9,800 feet]," said Rudolf von May, a postdoctoral fellow at the University of California, Berkeley who co-wrote a detailed survey of amphibians and reptiles in the park and its surrounding area, published in the journal Biota Neotropica.

Snakes are cold-blooded, he explained, so they need relatively warm temperatures to function. But "this snake is adapted to live at colder, higher elevations." Precisely how the snake does this is unknown, he added.

Von May and two colleagues—Alessandro Catenazzi of Southern