人类可能相信自己是世界上最伟大的探险家，但事实并非如此。每天有数以百万计的动物沿着已经使用了几个世纪的路径在全球范围内迁徙。它们翱翔、飞行、游泳，从南极洲到非洲大草原，从太平洋到阿拉斯加。这个系列让观...
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