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    Caribou

    Caribou -- or reindeer -- aren't confined to the North Pole. In fact, some North American caribou make the longest migration of any land mammal, traveling over 3,000 miles. The elk-like animals have large hooves that help them walk on the rough Arctic and subarctic landscape and paddle efficiently through water. The hollowed-out hoof also facilitates easy digging through snow for food; its sharp edges help caribou balance on rocks and ice.