This video is interesting; you see one male Yak is rolling on the ground, marking its territory, while you’ll see another male behind which has come to protect its territory. The stray male is chased away by the herders.
These animals are not scared in Bhutan but they are protected and live in unison with their herders. The herders live most of the year at high altitudes and never bath, they oil their skin to avoid burning or cracking. This was a rare chance to see the herders going back up to 4000+ metres which they do once per year.