High on the Tibetan Plateau of Central Asia, you'll find the largest remaining population of wild yaks (Bos mutus). This long-horned, shaggy creature has persevered through more than a century of poaching, habitat loss, and competition with domestic yaks and their human herders.

But now, these large black bovids are facing another challenge: climate change. The Tibetan Plateau (map) is experiencing an accelerated rate of rising temperatures—about double the rate seen in most of the rest of the world. And with that comes changes in precipitation patterns—including less snow, which is how the animals get their water. (Read "The Big Melt" in National Geographic magazine.)

So in the winters of 2006 and 2012, scientists traveled to this region, sometimes