A lone wolf weighs as much as four coyotes,
一只狼的體重是草原狼的四倍，
but one on one it's still no match for a bison.
但是一對一，狼還是敵不過野牛VVXCC1g!(1R~1w#f。
Wolves, though, live and hunt in packs of up to 15
不過成員數(shù)最多可達15只的狼群，
and when they launch a cooperative attack, they're devastating.
只要同心協(xié)力發(fā)動攻擊，將會無往不利n[)_k7E+tH_E。
First they get the bison on the run, then filter out the weak
一開始先讓野牛開始狂奔，從中篩選出虛弱的，
and vulnerable and select the perfect target.
在挑選完美的目標(biāo)Gg(jSqk(80)。
Striking together, wolves can bring down prey many times their own size.
群起而攻的狼群，可以絞殺打他們數(shù)倍的獵物)[bS7w||l)hruaU]3f。
A million such chases must have taken place across these plains
像這樣的追逐在大草原上，必定發(fā)生過百萬次，
and we can still find echoes of these distant life-or-death encounters.
我們?nèi)匀豢梢园l(fā)現(xiàn)這些遠古生死際遇的回生Jv_#5i4+qd。
Not all evidence lies locked in bone and rock.
并非所有證據(jù)都封存在骨頭或石頭中63ThV~NSW(H-g]6]#8。
These pronghorn antelopes among the great survivors of the ice age reveal a lot about the distant past.
這些叉角羚也是雄奇的冰河期生還者之一，揭示著許多遠古的記憶*RBZAG;Ezn。
As well as being tough enough to stand extremes of temperature, they're famous for their speed.
他們堅毅強悍，足以撐過極為嚴(yán)寒的氣溫，并以它們的速度聞名itU_LvSe5v4LqjDva。
A sprinting pronghorn can top 60 miles an hour and cruise at 30 for several hours.
飛奔中的叉角羚時速可快達60英里，還能以30英里的時速續(xù)跑數(shù)個小時Ch00T(Kf&5Pa。
This kind of speed requires a very finely tuned physique.
這樣的奔馳速度需要非常優(yōu)越的完美體格*Dw~6@yj&%nyaG]FR。
Pronghorn have a massive heart and run with their mouths gaping open,
叉角羚擁有巨大的心臟,)n9IcSX,Xs。奔跑的時候，長大著嘴，
forcing extra air into their huge lungs.
吸入更多的空氣進入巨大的肺部zgN&|SPv]Cf。
But what's the point? No predator can run this fast.
重點何在呢？沒有掠食者能跑這么快[qV@^t=#ij_!。
Even the wolves can only manage 40 miles an hour.
就連狼跑起來最快也只有時速40英里KEuo*DX57K1Ygw。
So why do pronghorn feel this need for speed?
為什么叉角羚需要這樣的速度呢？
This is why—once there was a predator here that could outrun the pronghorn a cheetah.
這就是答案: 這里曾經(jīng)有過一種掠食者，可以追的上叉角羚和獵豹SL^J_HrX]nHaGz]]1。