National Geographic : 1921 Sep
Photograph byDr. A.L.Shelton A CAMP OF NOMADS IN THE TIBETAN HIGHLANDS These nomads change their camps from the valleys to the mountain heights according to the seasonofthe year. Inthespring they follow the new grass as it appears below the ever-receding snow-line. In the fall, as the snow-line descends again,they keep just below itwith their herds of yak, until in midwinter they are in the lowest valleys (see page 298).