- his cubs will leave their mother and start to hunt alone,
它的幼崽将离开母亲 开始独自捕猎 - having learned all the skills they need
到时它们将学会一切所需技能 - to survive at the top of the world.
可以在世界之巅生存下去 - Although they had conquered the land,
虽然哺乳动物征服了陆地 - the mammals didn't stop there.
但它们并未止步于此 - One branched out and went in an entirely different direction.
有一个分支 朝一个完全不同的方向发展 - Fifty million years ago,
5000万年前