and the bison are now slowly starving. 美洲野牛越来越饥饿

248. it's about to be buried.
     马上还会被大雪掩埋
249. Sixty million tons of snow now blanket this herd's territory.
     六千万吨的积雪覆盖在野牛群的领地上
250. Pushing through deep snow is exhausting work,
     在厚厚的积雪中行动非常耗费体力
251. and the bison are now slowly starving.
     美洲野牛越来越饥饿
252. Just keeping warm saps huge amounts of energy.
     仅仅保暖都需要耗费大量的能量
253. Their thick coats can insulate them down to minus 20 Fahrenheit.
     他们厚重的皮毛可耐受零下三十度的低温
254. It's now minus 40.
     现在是零下四十度

来自《行星地球 第二季 第五集 Planet Earth S02E05 草原》第 251 行