Sanjim, a member of Mongolia's nomadic Tsaatan people, stands on the left as veterinarian Nansalmaa Myagar administers antibiotics to a reindeer. Her aide holds an IV in the background. Disease and inbreeding are serious threats to the Tsaatan's reindeer herds.

Read the news story about the Tsaatan people and their reindeer.

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Photo gallery by Chelsea Lane-Miller
National Geographic News