Alaska Department of Fish and Game biologist Jim Dau is among the state's most experienced caribou researchers, having spent much of the past 25 years on the tundra, observing the huge Western Arctic herd and gleaning further insight by talking to villagers about changes they've noted. Dau tells Smithsonian magazine that while he lacks hard data on the cause of the herd's decline over the past decade, he has suspicions.
In the last six, eight, ten years, we’ve had more rain-on-snow events than we used to. We’ve had more moisture fall, and it’s created icing conditions that seal the food. There’s food down there, but either the caribou can’t get to it, or when they finally do get to it, they’ve expended more energy getting there than they get out of it. I think that is what tipped the balance and started this herd going down.
I can also tell you I’ve seen more wolves in the last three to five years than I ever have, and brown bear numbers seem to be going up. That’s what virtually every villager I talk to tells me as well.
Read more at Smithsonian.com: Where's Rudolph? Inside the decline of Alaska's caribou