In two different years, during the height of the fall migration, I’ve watched as the entire herd stopped. Not for four or six hours but for two to three weeks. Then, within a several-day period, they resumed the fall migration. They must have keyed off some large stimuli, such as weather. But I don’t think it was just that because their halt and resumption of travel were so synchronous. It seemed like caribou that were separated by tens of miles and large geographic features, such as mountains, were somehow aware of each other’s movements. I don’t know how they could do that, but I suspect we grossly underestimate the sensory capabilities of caribou.
Rut happens during the fall migration, which is really an exciting time. Group sizes tend to get a little bigger during rut, and bulls become totally obnoxious chasing cows, other bulls; they pose to show off their antlers and grunt continually. It’s the only time of year that bulls vocalize.
In the spring, pregnant cows start migrating north about three weeks ahead of the bulls, and it’s pretty much a steady plod with these big long lines written out in the snow. It’s just beautiful to see these almost serpentine trails weaving out over the hills and mountains.
The Western Arctic Herd is the largest in the United States—aside from bragging rights, what’s the significance?
The herd’s ecological importance is incredible. It affects the entire food chain, all the way from bacteria to the biggest predators, such as wolves and brown bears. They affect the vegetation not just by what they remove with their lips by but trampling. They not only remove nutrients and energy from the environment, but contribute back towards the whole cycle with their feces and urine. They shed antlers and eventually their bodies and skeletons after death.
They’re also incredibly important to people. The Inupiaq people have subsisted on marine mammals and terrestrial mammals, like caribou, for thousands and thousands of years, but it’s more than just a source of protein for them. Caribou are really central to their cultural identities and many of their customs, such as the development of extensive social networks for sharing subsistence food that go along with hunting and using caribou.
They’re also incredibly important to the commercial operators who transport hunters, hikers or floaters, the people who come up here from the Lower 48. Regardless of where people live or why they visit remote portions of Alaska, an opportunity to see thousands or even tens of thousands of caribou in a one to two week period is truly memorable.
What’s to blame for the herd’s declining numbers?
I’ve lived here and been a biologist for 25 years; I fly up to 600 hours a year looking at caribou and I talk to literally hundreds and hundreds of people, asking them the same question you just asked me. I don’t have any hard data to tell you.
Here is what I think is going on. 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.