Arctic circle

the long version

"Every year without fail, caribou from the Yukon and Alaska set off in early April to a small corner of Alaska to give birth to their young. The journey - an ordeal of mountains and blizzards, ravenous wolves, scant forage, and river crossings with ice chunks the size of pickup trucks - is the longest migration of any land animal on earth. Despite these formidable obstacles, the females find their way to the calving grounds on the coast of the Beaufort Sea, deliver their calves in June, and then begin their long journey home."--Pub. desc.