There’s a chill in the air this week as we travel to a mountain range in Norway in search of muskoxen, Ice Age survivors that once roamed the far north alongside the woolly mammoth. Introduced to Norway from Greenland in the 1940s, muskoxen flourished on these cool, dry slopes until 2006, when the seemingly healthy animals began to die. Ari Daniel Shapiro investigates the muskox mystery.
