while the caribou pass through their territory. 驯鹿经过领地时把握住机会
trying to flush out the weak or the slow. 试图冲散群体中的弱者
The caribou mothers now join together, 母驯鹿现在聚集起来
each with an infant exactly the same age. 每只都带着一只同样大小的幼鹿
They're testing the legs that will carry them thousands of miles, 他们正在测试自己跋山涉水用的四肢
It may look playful, but there's no harder life on the grasslands 看起来很好玩 但草原上最艰苦的生活