There were once 60 million bison, 这里曾有六千万只北美野牛

135. But further south, summers are longer and the grasslands flourish.
     但是在更远的南边 夏天的时间更长,草原更加茂盛
136. The prairies of North America.
     北美大草原
137. This rich pasture once supported the greatest herds ever seen on our planet.
     这里的大草原肥沃甘美 曾经养育着地球上最大的动物群落
138. There were once 60 million bison,
     这里曾有六千万只北美野牛
139. but no animal is immune to intensive hunting by man
     然而没有哪种动物能够幸免于人类的大捕杀
140. or the destruction of its habitat.
     野牛的栖息地也惨遭破坏
141. And a century ago, the bison were reduced to barely 1,000.
     一百年前 野牛的数量曾锐减至不到一千

来自《行星地球 第一季 第七集 Planet Earth S01E07 伟大草原》第 138 行