and have been hunting bison in America for more than 100,000 years. 其在美洲捕杀野牛的历史 已经超过10万年
a mammal armed with more intelligence and adaptability than any before. 一种哺乳动物 拥有史上最强的智力和适应性
But there is one more chapter in the mammal story still to be told. 但是哺乳动物的故事 还有一章仍待讲述
This is much more than about speed. 这不仅仅是速度的问题
they use oxygen far more effectively than Maiacetus. 它们利用氧气的效率远高于慈母鲸
the skies belong to the bats once more. 天空再次归蝙蝠所有
it became a harsher, more difficult place to live. 它成为了 一个更恶劣、更难以生存的地方