All they can do is continue their migration 它们只能继续迁徙

81. ...knows it's a lost cause.
    知道木已成舟
82. They have no choice but to back down
    它们别无选择 只得退下
83. and protect the generations that remain.
    继续保护余下的后代
84. All they can do is continue their migration
    它们只能继续迁徙
85. across the cold tundra-steppe.
    穿过这寒冷的冻原
86. While ice never completely engulfed the planet,
    尽管冰雪从未覆盖整个地球
87. its impact was still felt across the globe...
    但它仍对全球产生了影响

来自《我们星球上的生命 第一季 第八集 Life on Our Planet S01E08 冰与火的世纪》第 84 行