我们平时去一个不熟悉的地方,常常需要手机导航帮忙。可是自然界中有些生物,却像是天生就自带指南针属性,可以长途跋涉不迷路,例如帝王蝶、鲑鱼、龙虾、海龟、迁徙的鸟类等。还有一些生物,会按照地球磁场的方向筑巢、打洞或者睡眠,如指南白蚁、裸鼹鼠等。科学家们认为,生物之所以具有这种神奇的“方向感”,原因之一在于它们的感觉系统除了视觉、听觉、嗅觉、触觉、味觉之外,还有被称为“第六感”的磁觉,即生物利用地磁场准确寻找正确的方向。
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