Jaw from a mysterious human species shows early embrace of the high life

Four decades ago, a monk came to pray at a limestone cave two miles above sea level in the Tibetan Plateau. There the monk found half of a human mandible. He took the bone from the cave, and his village gave it to scientists working in the area, who stored the jawbone in an archaeological collection.
In 2010, archaeologists began studying the fossil and made a remarkable discovery: This high-altitude jaw is not like yours or mine. Proteins pried out of its ancient teeth revealed the mandible belonged to a Denisovan, an extinct human species related to Neanderthals.