while the caribou pass through their territory. 驯鹿经过领地时把握住机会

300. predators lie in wait.
     都有捕食者等待着他们
301. Here they are, Arctic wolves.
     就是他们 北极狼
302. They must seize their chance
     他们必须要在
303. while the caribou pass through their territory.
     驯鹿经过领地时把握住机会
304. The wolf runs at the herd,
     北极狼跑向鹿群
305. trying to flush out the weak or the slow.
     试图冲散群体中的弱者
306. A calf is separated.
     一只幼鹿走散了

来自《行星地球 第二季 第五集 Planet Earth S02E05 草原》第 303 行