Humans are hairless, clawless and mostly weapon-less. And so ancient people had to use their abilities to run long distances, sweat and show determination to get an advantage over faster, stronger and more dangerous animals. Let's start with their ability to run. Most animals that we consider to be excellent runners like cheetahs and leopards are built for speed, but not distance. Even animals best distance runners, such as horses and dogs, will only run for a long time if they absolutely have to. And yet each year millions of people around the world choose to run marathons because we're built to run long distances.
We can swing our arms, hold our bodies up straight and keep our head still. We have long legs and feet that store energy, which make it easier to take another step. Whereas other animals have to use a lot more energy to do this. Our ability to sweat might not seem like an advantage, but it allows us to lose heat when we're running in high temperatures. We can also breath through our noses and mouth when we run, which is important because other animals can’t. I think it's likely that ancient humans caught animals by tracking them during the hottest part of the day. They chase the animals again and again over long distances without stopping until the animal finally became overheated and collapsed.