Mongolia has a many-thousand year history of herding livestock. But in the past two decades, tens of thousands have left the countryside because of a natural disaster you may have never heard of. "Dzud" kills animals en masse during winter. Short Wave reporter Emily Kwong brings host Maddie Sofia this story from the grassland steppe, capturing how an agrarian community has adapted to environmental change. Follow host Maddie Sofia @maddie_sofia and reporter Emily Kwong @emilykwong1234 on Twitter. Email the show at shortwave@npr.org.