But they weren't alone. 但它们并不孤单

219. In the absence of competitors,
     没有了竞争对手
220. bison took over the great plains...
     野牛接手大平原
221. ...roaming in huge numbers.
     四处游荡 数量庞大
222. But they weren't alone.
     但它们并不孤单
223. With fewer big prey to choose from,
     由于大型猎物减少
224. bison became the focus of another group of survivors.
     野牛成为另一群幸存者的重点目标
225. Age-old enemies.
     宿敌

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 222 行