One theory suggests that the Red Deer Cave people were early humans that settled into the region more than 100,000 years ago and became isolated. The high mountains and deep valleys are ideal in isolating species geographically, so it is possible for a species to migrate to the area and become genetically isolated over time. The environment and climate of Southwest China are unique owing to the tectonic uplift of the Qinghai-Tibetan Plateau. The Yunnan province still today has some of the greatest biodiversity in all of China.