they are rarely the top predators their towering ancestors once were... 它们却极少像高大的祖先那般 成为顶级捕食者

261. Their exceptional intelligence and remarkable senses
     非凡的智慧和卓越的感官
262. have helped cephalopods colonize every ocean on Earth.
     帮助头足动物 占据了地球上每一片海洋
263. Yet, in the shallows,
     但是在浅海中
264. they are rarely the top predators their towering ancestors once were...
     它们却极少像高大的祖先那般 成为顶级捕食者
265. because in the ancient seas,
     因为在古老的海洋中
266. there was to be a changing of the guard.
     即将发生权力转移
267. Seventy million years after the great melt,
     大融化7000万年之后

来自《我们星球上的生命 第一季 第二集 Life on Our Planet S01E02 第一前线》第 264 行