There is a legend about the yak
In the ancient time, the ancestors living in the snow mountain, the grassland is not enough, so the brother discuss to the new grassland. The god is appearing, leading the herd. There is one white yak coming leading the yaks. And then fighting with the monster. Suddenly, it kills the monster. And then with the god reappearing, all the mountain snow are green, and people start their happy life.
Another is about yak is the other mountain. According to the fighting, luowang kill the zanpu. And then his wife give birth to blood. And then it becomes the minister of budaigongjia.
Tianzhu yak has long history, early in the 3000-4000 years, there is little yak moving in the mountain. In the long time livestock life, yak get he development.