One theory holds that human beings evolved by running. But humans are slower than either predator or prey animals. What gives?
Human being are vulnerable to cold and heat, have fragile tearable skin without the protection of thick coats, offspring that are difficult to birth and take forever to raise, and brains that suck down 1/6 of the body's energy per day.
Physically, we aren't a pick for evolutionary advancement. Most stories of the evolution of humans focus on mental abilities. Humans have big brains. We have complicated facial muscles that let them communicate their braininess through expression and through speech. We have clever hands that allow them to manipulate matter well enough to build the things their brains imagine.
All of this is true. But it's not alone. In addition to special mental ability, humans may have developed a special physical ability: jogging.
At the surface, jogging doesn't seem like anything special. Jogging won't get anyone out of the way of a lion. It won't help anyone run down a rabbit. Humans are generally much slower than our predators or our prey. And yet, we developed a host of physical traits meant for running.
One of the major traits our ancestors developed were tendons. Tendons around the knees to cushion and store energy, tendons on the ankles to spring forward, and perhaps most tellingly, a tendon connecting the head to the body. Not present in walking four-legged animals or in chimp-like human ancestors, ridges on the skull to anchor such a tendon were found the fantastically successful Homo Erectus. This tendon kept the head steady as the body ran, reducing injury and allowing it to keep eyes on the prey.
Another major trait was heating and cooling systems. Noses regulated the temperature of the air before letting it into the body, sweat glands shed heat without the need to pant. Hairless bodies allowed people to keep from overheating when their hairy prey would be feeling the strain of the sun.
There were also minor things, like moving arms and a big butt to help with balance, and a long neck to scope out prey.
All of these things are not important when walking, but figure hugely in jogging.
Which doesn't matter much, if it doesn't help humans get food, sex, or protection. Jogging is not so sexy, and doesn't help people escape large predators, but it can prove a successful way to hunt, especially when the temperature climbs.
Humans can efficiently shed heat by sweating. Animals, with their coat of fur, can't do the same. This means that endurance hunters don't have to outrun an animal, they just have to chase it until it drops from heat exhaustion. It sounds pretty daunting, and it is. Endurance hunts can take two to six hours. Those two to six hours aren't filled with sprinting, though. The hunters move at a rate of 4-6 miles per hour. Four miles an hour is a fast walk. Six miles per hour is a decent jog. The hunters don't have to run the animal down, just keep it in sight and keep it moving until it can't go any further. It's something that humans are seemingly uniquely qualified to do, and that confers a huge advantage.