Following is a transcript of the video. Narrator: Cheetahs are the fastest land animal in the world. But did you know that humans can leave them in the dust? At least, in the long run. That's ...

Australopithecus afarensis is one of the best-known early human ancestors dating from 2.9-3.9 million years ago ... Run fast (bursts of speed to outpace an unaware animal), and run for long amounts of ...