Mammals had a long way to go to become masters of the world's oceans, 哺乳动物想要成为海洋的主宰 还有很长的路要走
The Maiacetus is running out of air. 慈母鲸的氧气快用完了
Twice the length of a great white shark. 身长是大白鲨的两倍
The mammal's intelligence is his only defense... 哺乳动物的智慧是它唯一的防御手段
two-and-a-half-meter-long ancestors of the whales. 身长2.5米 是鲸的祖先
It's in the water that they come alive... 在水中 它们才会活跃起来
...attracted by the abundance of food hidden beneath the waves. 它们被海浪之下的丰富食物所吸引
The mammals' journey into the oceans was a gradual one. 哺乳动物进入海洋的过程是渐进式的
other mammals were moving into the sea... 另一些哺乳动物则正在下海
At the same time as bats were first moving into the air, 在蝙蝠首次上天的同时