Human males are not as fast as their prey, but they have two advantages. The first is that after learning to stand and balance on two feet, the early humans rapidly became the most efficient animals at moving. They lost their insulating hair as they discovered warming fires and clothes, meaning that they could cool themselves very efficiently by sweating, compared to most animals that rely on panting to cool their bodies when running. Humans take less energy per unit weight than any other mammal to move distances.
