It’s official: the Arctic tern has the longest migration of any animal in the world. The Arctic Tern Migration Project recently discovered that the tern flies over 70,000 kilometers (43,496 miles) annually, from its breeding grounds in the Arctic to its winter quarters in the Antarctic. That distance is more than twice what was previously estimated. Over the lifetime of one bird, it travels approximately 2.4 million kilometers, the equivalent of three trips to the moon and back. For a bird that weighs just over 100 grams (3.5 ounces), that’s fairly impressive.