这些庞然大物都是孤独行者，特别是在现在的海洋里。 过去，聚集成群往往是鱼类躲避掠食的方式， 但现在这样却无异于自杀。
So being a loner is a great thing, especially in today's seas because schooling used to be salvation for fishes, but it's suicide for fishes now.
就如许多引进的物种一样，美国貂也能通过生态系统杀出一片生机，因为它们没有本土的天敌，而它们所掠食的物种还没有进化到可以躲避它们的掠食。
Like many introduced species, American mink can slash their way through the ecosystem, as they have no native predators, and their prey species haven't evolved to avoid them.
有时候，色彩的快速变换可以用来惊吓掠食者或威胁入侵者。
Sometimes a sudden shift in color can be used to startle potential predators or threaten intruders.
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