The Mongolian pastoral nomads relied on their animals for survival and moved their habitat several times a year in search of water and grass for their herds. Their lifestyle was precarious, as their constant migrations prevented them from transporting reserves of food or other necessities. Rarely having the luxury of surpluses to tide them through difficult times, they were extremely vulnerable to the elements. Heavy snows, ice, and droughts (judging from contemporary times, droughts afflicted Mongolia about twice a decade) jeopardized their flocks and herds and heightened their sense of fragility. The spread of disease among the livestock could also spell disaster. Herders hunted and farmed to a limited extent but were dependent on trade with China in times of crisis.
"Mongolian Herders Struggling to Survive," by John Leicester, in Mongol Tolbo 21 (March 2001): 6-7.