Caribou crossing the Noatak River/NPS, Kyle JolyIt is a spectacle of the animal kingdom, one most of us don’t see in person, but are amazed when it is shown on television. “It” is the crossing of the Kobuk River far north in Alaska by hundreds of caribou. It is a swim caribou have been making in the landscape of present-day Kobuk Valley National Park and Preserve for thousands of years.

“I’m a very lucky person to have the job that I do and to see what I get to see,” admits Kyle Joly, a wildlife biologist for the National Park Service whose “office” embraces the landscapes of such places as Kobuk Valley, Gates of the Arctic National Park and Preserve, and Noatak National Preserve.

Kobuk Valley has been “the home of caribou migrations for 10,000 years. There’s an archaeological site there that’s dated hunting of caribou back that far,” Joly went on. “The river is probably a quarter-mile wide at that point, and there will be times when you have several hundred animals on the shore. You’ll have caribou nose-to-tail all the way across the river, and a couple hundred more piled up on the south bank. It’s definitely a wildlife spectacle that is on par with anything on the globe.”

That spectacle, of hundreds and even thousands of caribou traveling en masse, is a wonder of nature. It is also at times the longest migration on Earth, a claim that reindeer also can make.

“Most people don’t know this, but caribou and reindeer are actually the same species,” Joly said. “Caribou are found in North America and reindeer are found in Europe and Asia, but they’re the same species and they can interbreed freely. That species, both caribou and reindeer, have the longest terrestrial migrations on the planet, with a number of populations migrating 1200-1350 kilometers (745-839 miles) in a year.”

via Climate Change Could Be Influencing World’s Greatest Terrestrial Migrations