Prehistoric humans settled on the Tibetan Plateau, also known as the “roof of the world,” about 3,600 years ago. And what helped them survive such high altitudes? Barley, according to a new study published in the journal Science. Science said that without frost-resistant crops, especially barley, it would have been almost impossible for early humans to establish permanent settlements on the roof of the world.

Barley Tibetan plateau

How Tibetans got barley

A team of scientists led by Martin Jones, an archaeology professor at the University of Cambridge, studied animal bones, plant remains and artifacts from 53 sites in the northeastern Tibetan Plateau to find out how ancient humans were able to survive, thrive and build a unique culture in the high altitude. Evidence suggests that there was intermittent human presence as early as 20,000 years ago.

But the first semi-permanent villages in the Tibetan Plateau settled only about 5,200 years ago. Crops and livestock appeared even later. Those settlements were limited to altitude below 2,500 meters. Then, about 4,000 years ago, barley and wheat were introduced to this region from the so-called Fertile Crescent, which covered modern day Israel, Syria, Iraq, and Jordan. Domesticated sheep also came to the Tibetan Plateau around the same time.

Tibetan plateau no ideal place to live

Gradually, Tibetans began to move upland, relying less and less on millet as they switched to barley. Thus, they were able to establish permanent settlements above 3,000 meters. Barley is still an important cereal for modern Tibetans. They had to shun millet crops due to their frost sensitivity. Millet couldn’t hold up to the frosts present above 3,000 meters. The Tibetan Plateau is no ideal place to live because of its high altitude, relentless winds, frigid temperatures and low-oxygen.

Notably, scientists said that the early human settlements in the colder, higher altitude took place at a time when the world was getting colder. There might be insufficient food resources as the temperature drops, prompting people to move to other areas or adopt new technologies. Scientists from the UK, United States and China participated in the study.