Tibetan nomadic yak herder Karsal's wife, Phurba, has milked one of the family's dris in the early morning at their tent on the Tibetan Plateau. (Karsal is featured in the book What I Eat: Around the World in 80 Diets.) The male yaks remain free at night, grazing at higher elevations, and the dris and their calves are tethered close to the tent to make milking in the morning convenient.