Joel Berger

Wildlife biologist, University of Montana and Wildlife Conservation Society

Missoula, Mont., and Bronx, N.Y.

There are around 14 million domestic yaks in the world, but nobody knows how many wild yaks there are. They're a vulnerable species. The Tibetan Himalayan region, their home, has tens of thousands of glaciers, and as the snow and the ice melt, we're not sure what it's going to do to yaks. Our expedition to the Tibetan plateau last November and December was to get a better handle on where we can find yaks and start to figure out how they're going to respond to changes. We picked that time of year because everything is frozen solid, and we can drive across lakes and marshes. Temperatures get pretty cold: it's an interesting challenge to get out of a sleeping bag when it's −20 degrees Fahrenheit.

We did a snapshot survey in the northeastern corner of the Tibetan plateau, where we counted about 990 yaks. Poachers have targeted wild yaks for their meat and hide up until the past half a century. Our Chinese collaborators have done a great job with antipoaching patrols, and it appears that the yak numbers are coming back, but we don't have good measures of the trends.

Wild yaks used to occur down to elevations around 10,000 feet, whereas now they are restricted to elevations around 14,500 feet—and up to 17,500 feet. It's likely the reason that they don't occur at such elevations now is contact with people [who have encroached on their territory] rather than temperature intolerance.

When I think about these places at the limits of life, I think about the future. Ultimately, what can we do to ensure the persistence of wild yaks? What kind of actions do we need to take that also account for human livelihoods in that area? I work with colleagues, government employees and herders because they care just as much as I do. If we don't address the concerns of people, we're never going to conserve the species.