Pronghorn

The modern pronghorn ( American antelope ) presents a puzzle .

现代的叉角羚（美洲羚羊）仍然是一个谜。

But the mother pronghorn must leave her calves alone while she grazes .

但是这位母亲叉角羚在放牧的时候必须离开她的小牛犊们。

Like pronghorns , springbok are very agile with sharp senses .

和叉角羚一样，敏锐的感官使得跳羚十分机警。

Pronghorns are designed for running , but sometimes they can accomplish amazing jumps , especially under immense pressure .

叉角羚卓越的奔跑能力与生俱来，它们的弹跳能力也十分惊人，尤其身处巨大压力时。

Pronghorns also have hooves that have cushions underneath that work as shock absorbers as they run .

同时，蹄子下面的软垫如减震器一般起保护作用，避免运动受伤。

To learn about those , we turn to the mystery of the pronghorn .

要想了解这些生物，我们首先来看看谜一般的叉角羚。

The answer is that the world in which the pronghorn evolved was a much more dangerous place than ours .

答案在于叉角羚进化时所处的环境远比现在的环境更加危险。

in theory , put the pronghorn back onto its ... uh , natural evolutionary trajectory according to these biologists .

在理论上就可以将叉角羚放回在其自然那的进化轨迹上来。

Why did the pronghorn evolve such speed ?

那么叉角羚为什么会进化出这么快的速度呢？

Typical of the grassland dwellers of the continent is the American antelope , or pronghorn .

美洲羚羊，或称叉角羚，是该大陆典型的草原植物。

The pronghorn is America 's fastest mammal .

叉角羚羊是美洲跑得最快的哺乳动物。

When the American cheetahs disappeared , their influence on the evolution of pronghorn and presumably on other prey animals stopped .

当美洲印度豹绝种以后，它们对叉角羚及其他可能猎食的动物进化的影响就停止了。

On a40-acre field at the edge of town where pronghorn antelope once grazed , they built it .

在该镇周边曾经出现羚羊的40英亩的土地上建造了这座监狱。

So it is conceivable that the pronghorn antelope would have continued to evolve , get faster maybe , if the cheetahs were still around .

所以可以想象，如果印度豹还存在的话，叉角羚本可以继续进化，跑的更快。

When a pronghorn in the herd sees danger , it raises the white patch of hair on its rump as a warning signal to the others .

叉角羚羊群中谁发觉险情，便将它臀部上的白色毛块突起，向其他羚羊发出危险信号。

But pronghorn have tremendous vision and are not fond of strangers , so Riis set up motion-triggered cameras to capture pictures like this .

但是叉角羚的视力非常好，它们很不喜欢身边有陌生人，所以里斯架设起了动态捕捉照相机。上面的照片就是这样拍摄的。

We believe it played a pivotal role in the evolution of the pronghorn antelope , the antelope 's amazing speed , to be exact , because natural selection would favor those antelope that could outrun a cheetah .

我们相信它在叉角羚的进化中起重要的作用，精确来讲，羚羊惊人的速度是一种自然选择的结果，因为只有能跑过印度豹的羚羊才能生存下来。

The predators we met earlier , the fleet-footed creatures who may have preyed on the pronghorn , were joined by another terrifying carnivore , a long-limbed hyena that resembled a modern wolf .

我们之前见识到了跑得飞快的以叉角羚为食的各种猎食动物，现在马上就会看到另一种残暴的食肉动物，一种长得很像现代狼的长腿土狼。