Humans - Long Distance Runners

I always thought I was running for a reason. Even if I didn't know the reason.

Like I was running for my ancestors or something. Or I was looking up in the sky for "birds of prey" to see if they were circling, and I was running to beat them to the prize.

Or I was running after some mythical animal that I was hunting. They pant, I sweat. Advantage me.

Or I was being chased by something. Something big and invisible.

Supposedly people can outrun horses over long distances on a hot day. Man, I know I bet on some ponies on hot summer days that I could have probably out-run.