In the absence of competitors, 没有了竞争对手

216. North America was particularly hard-hit,
     北美尤其遭受重创
217. losing over 70% of its giants...
     失去了70%以上的巨兽
218. but not all.
     但也有例外
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

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 219 行