they need little energy to keep warm... 所以它们不需要多少能量 就能保持温暖

11. Temperatures can drop below minus 50 degrees.
    温度会降至零下50度以下
12. Only those built for the cold can survive.
    只有为寒冷而生的生物才能存活
13. A bison's thick coat is such good insulation,
    野牛厚厚的皮毛是出色的隔热材料
14. they need little energy to keep warm...
    所以它们不需要多少能量 就能保持温暖
15. which is just as well,
    这也非常重要
16. as grass is hard to find beneath the snow.
    因为冰雪之下很难找到草
17. But bison aren't the only hungry ones here.
    但野牛并不是这里唯一饥饿的动物

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 14 行