is heating our planet faster than at any time in the last 500 million years. 正在以五亿年来从未有过的速度 令地球升温
their muscles are always at a temperature for maximum performance... 肌肉始终保持在最佳性能的温度
At the same time as bats were first moving into the air, 在蝙蝠首次上天的同时
to survive at the top of the world. 可以在世界之巅生存下去
At these altitudes, mammals must feed regularly to keep warm. 海拔如此之高 哺乳动物必须定时进食以保持体温
the Americas were still at the mercy of the terror birds. 美洲仍在骇鸟的蹂躏之下