if others are on the lookout. 因为旁边有站岗的“哨兵”

55. You might expect that grazers would avoid each other's patch
    你或许会认为食草动物 总是尽量互相避让
56. but this is a special alliance from which both partners benefit.
    但是这种特殊联盟能使双方都得到好处
57. It's not so risky to put your head down
    它们可以毫无顾虑地埋头吃草
58. if others are on the lookout.
    因为旁边有站岗的“哨兵”
59. Ethiopian wolves -
    西门豺
60. they won't attempt an attack in broad daylight.
    它们一般不会在大白天发动进攻
61. But at dusk the plateau becomes a more dangerous place.
    可是一到傍晚 高原便成了 一个危机四伏的地方

来自《行星地球 第一季 第二集 Planet Earth S01E02 山地》第 58 行