Why do aboriginal tribes all over the world live mostly in the mountains?

I have read several stories about the people with long lives, even from the Soviet Union time. At that time Georgia was a part of SU and was famous for the live length of the native people in the mountains. Not one story, but several from different villages about people who lived "unreasonably" long. Age over 100 was a king of "norm" and sometimes noted cases of 300-500 years old. However because all that people never had any official ID, formally this does not exist.

Have you noticed the fact the all around the world aboriginal tribes mostly live in mountains? All tribes in Taiwan (6 of them) are high mountain people.

According to the history of agriculture, all cultivated plants originate from one place - valley of the mountain Ararat.

During great flood only mountains tops where available to live above the water. Noah had landed to the top of Ararat and later slowly was moving down as water retreated. Than the agriculture was given to humanity in the form of seeds and certain domestic animals. All started in the valley of Mt. Ararat. 

Georgia mountains are close and connected to the valley of Ararat, so direct relatives of the pre-flood people, like Noah, start to spread over there.

However in the other parts of the world there were Igigi with their families (tribes) in the exile. They were informed about the coming flood and found refuge on the mountain tops. Later survivals moved down with the water, but still aboriginal tribes (direct descendants of Igigis) mostly stayed in the mountains and kept their original culture.

Here is my simple theory: often we can hear stories about persons with the long life from the traditional or aboriginal mountain villages because they are closer descendants of the Anunaki or Igigi. And by following ancient traditions sometimes they may extend their lives without knowing about it. For example, once we had a tourist trip around the mountains in Taiwan and tour guide showed us a special rock formation and told us that aboriginal people believe that should eat this rock for certain health benefits. Everyone from our group including me because of curiosity did eat a bite of that rock. And later everyone happily forgot about it. I remembered this only now while typing this mail. I should go back to the rock to listen more stories and to collect samples.

Making sense?