TIBET: Without yaks, which provided an essential source of meat, milk, and transportation, humans would have struggled mightily to sustain themselves in the harsh conditions of Himalayan mountain valleys. However, until recently it was not known when yaks were first domesticated. Sequencing of DNA from animal bones found at the site of Bangga, one of the earliest agropastoral settlements on the southern Tibetan Plateau, has revealed that yak domestication occurred at least 2,500 years ago.