For early man, surviving and conquering niche environments, like that of the Tibetan Plateau of Asia, was a difficult task that required the perfect combination of conditions. Tribes needed to learn how to work together, to traverse harsh terrain, to find/build shelter, and above all they had to learn how to feed themselves year-round. And while the surmounting odds of surviving the domain known as the "Roof of the World" were stacked against them, with extreme altitudes, relentless winds, frigid temperatures and low-oxygen conditions complicating the living conditions they had in their new home, researchers now say that early men were able to conquer this uninhabited ecosystem thanks to a cold-hardy crop used to make beer - barley.

Publishing their results this week in the journal Science, archaeologists from the University of Cambridge described 53 archaeological sites in the Qinghai province in northwest China, where remnants revealed evidence of human habitation in intense regions from 5,600 to 11,000 feet above sea level. And while signs of periodic human presence in the region date back to the Ice Age at least 20,000 years ago, researchers say that permanent settlements with agriculture and livestock practices emerging 3,600 years ago were contingent on the introduction of species like barley which were imported into the region.

"They could quite plausibly be the earliest sustained settlements in the world at this altitude" co-author on the study, archaeologist Martin Jones says. "As barley is frost hardy and cold tolerant, it grows very well on the Tibetan Plateau even today."

"Therefore, barley agriculture could provide people enough - and sustained - food supplies even during wintertime."

While later practices and cultures brewed the aromatic barley with hops in order to create the alcoholic beverages now known as beer, early agricultural practices developed the grain alongside high-elevation crops like wheat as well, though neither crop was native to the region. Originally domesticated in the "Fertile Crescent" of Asia roughly 4,000 years ago, the introduction of the species and its hearty thriving came as a surprise and a blessing to the original pioneers of the Tibetan Plateau. But they weren't the only factors leading to their success.

Researchers also say that livestock was of vital importance in sustaining early settlements. And by domesticating sheep, around the same time as barley and wheat, early settlers were able to conquer extreme altitudes, and expand their habitats even higher over time.