This African huntress needs to run as fast as she can so she doesn't end up a light snack for this Tyrannosaurus rex.

While T. rex's multi-ton mass would have slowed it down relative to other theropods, its top speed---18 to 25 miles per hour depending on which sources you trust---would have exceeded most humans at least in a short burst. But I tend to imagine it more as an ambush hunter than a pursuit predator. On the other hand, some anthropologists believe that humans are actually better built for endurance running than other animals; foraging hunters like the Khoisan of southernmost Africa have taken advantage of this by relentlessly running after their prey until it tires before they do.