[00:03.15]To find the answers, we need to rewind history around 14,000 years to a time when the first people set foot in North America. 
为了找到答案，我们需要重新回顾14000年前的历史，那时，第一批人类踏足北美大陆，
[00:13.79]The continent was about to undergo a profound change, a change these new arrivals may have played a part in.
而大陆也即将经历一次深刻的变化，这个变化就是由这些新的到访者带来的。
[00:22.42]Throughout the ice age, North America was home to a variety of giant creatures. 
在整个冰河时代，北美都遍布各种大型生物。
[00:45.44]But in little more than a thousand years of the first humans' arriving, almost two thirds of the largest animals were extinct.
但是就在人类踏足北美大陆一千年多一些的时间后，二分之三的大型动物都已经灭绝。
[01:00.62]What role did people play in this mass extinction? To learn about their lives, you have to look at the clues they left behind.
大型生物灭绝的范围如此之大，人类在其中起了怎样的作用？想要知道他们的生活，你就必须从他们遗留下来的痕迹中寻找线索。
[01:12.06]Archaeological finds tell us that the first people in North America had an advanced Stone Age technology. 
考古学发现告诉我们，北美洲第一批人类具有先进的石器时代的技术。
[01:21.56]They were master of flintknappers meticulously chipping and sharpening pieces of flint to make spears and cutting tools. 
他们擅长用打火石精细雕刻，用尖利的碎石片制作长矛以及削制工具。
[01:28.99]From the examples they left behind, it's obvious they were well equipped to hunt.
从他们留下的工具来看，很明显，他们打猎时很好地利用了这些工具。
[01:43.87]And we know from spear points found alongside mammoth remains that these hunters tackled even the biggest beasts on the continent. 
从猛犸象化石上的长矛凹痕我们可以看出，这些猎手们甚至可以扑杀北美大陆体型最大的生物。
[01:52.84]Mammoths would have been a prized source of protein, providing enough meat to feed their families for weeks. 
猛犸象肉蕴含丰富的蛋白质，扑杀一头，便能喂养他们的家庭数周。
[02:01.24]The hunters probably worked in pairs or small groups. Any mammoth straying from its own herd would have been singled out.
这些猎人们可能几个人一组或多个人一组。任何离群的猛犸象都可以成为他们的猎物。