Where’s Rudolph? Inside the Decline of Alaska’s Caribou | Science | Smithsonian
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Where’s Rudolph? Inside the Decline of Alaska’s Caribou

The antlered herd’s population is declining – what’s going on in the Alaskan wilderness?

smithsonian.com

As Christmas approaches, young eyes will be focused on the sky searching for a glimpse of Santa and his reindeer—or are they caribou? The differences between the two are mostly taxonomic—both are subspecies of Rangifer tarandus, but Jim Dau of Alaska’s Department of Fish and Game is quite familiar with the subtleties of the antlered cousins.

Dau studies the Western Arctic caribou herd, among the largest in the world at 300,000 strong, that ranges over an area about 143,000 square miles in northwestern Alaska. While those figures might sound impressive, the caribou population has been steadily declining since 2003, when the herd peaked at nearly half a million. The decline is a source of concern for biologists studying the trend’s effects on the food chain, as well as for the more than 40 native villages that rely on the animals for food and as a cultural centerpiece.

The herd’s calving grounds are located within the National Petroleum Reserve-Alaska, also home to North America’s largest coal deposit. Currently, the Bureau of Land Management, which oversees the NPR-A, is in the last stages of finalizing the NPR-A’s new management plan—a document that will be instrumental in dictating the future of the Western Arctic caribou and to what degree energy development might infringe on the caribou’s turf.

Dau has spent the last 25 years living in remote Arctic villages in order to study the regal beasts.

Aside from the fact that caribou aren’t employed to haul Santa’s sleigh, what’s the difference between reindeer and caribou?

In North America, reindeer can be privately owned while caribou are wild animals that are public resources.

There are also biological differences between North American reindeer, which were transplanted to northwestern Alaska from Europe beginning in the late 1800s, and caribou. For example, the whole annual cycle of reindeer is one month ahead of that for northern Alaska caribou—for example they rut a month earlier and give birth a month earlier.

As well, there are physical and behavioral differences between them. Caribou tend to be taller and rangier than reindeer; as a result, caribou can run much faster than reindeer. Female reindeer tend to be heavier with larger and more fully developed antlers than adult cow [female] caribou. For bulls, these differences are reversed. Although most reindeer are colored similarly to caribou, reindeer are occasionally white or spotted while the pelage of caribou rarely varies. Caribou are generally much less trusting of man than reindeer, although the latter quickly become increasingly wild when untended by herders.

The Western Arctic Caribou herd’s annual migration may not be as famous as the reindeers’ mythical trip on Christmas Eve, but it’s amazing in its own right.

During the fall migration caribou are often spread throughout most of their range. For the Western Arctic Caribou Herd this encompasses about 143,000 square miles. An individual caribou from this herd may migrate 300 to 500 straight-line miles from the beginning to the end of its migration. Of course, caribou don’t move in straight lines, for more than several seconds anyway, and an individual may travel several times that distance during the course of a migration as it searches for food, evades predators and seeks out other caribou.

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