The Evolution of Running: Before running, there was Lucy

Lucy as she is commonly known (her real scientific name is AL 288-1) is still hailed as possibly the oldest direct ancestor of the human species. Her skeleton was found in 1974 in Ethiopia and is estimated to be 3.2 million years old. 

Australopithecus afarensis – forensic facial reconstruction. Cicero Moraes

Lucy became famous because the features of her skeleton presented clear evidence that she had been walking upright and also provided further proof that humans first evolved out of Africa.

In other ways though, Lucy still was more like an ape. Her diet was likely vegetarian as indicated by her conical and ape-like rib-cage with space for a larger stomach and intestine to digest large volumes of plant matter.

Also, her brain was relatively small (500cc) and not significantly different from her ape relatives and – bipedal as she was – she certainly was not a runner.

In 2004, Daniel Liebermann, a professor of human evolutionary biology at Harvard University and a passionate runner himself, published a paper in Nature that changed our view on human evolution as humans developed a capability to not only walk but run for long distances at a time.

He describes that at around 2 million years ago, three things happened in parallel in our evolution as early humans: we started eating meat, our brains started to grow significantly and we developed anatomical and physiological adaptations that made us particularly good runners.

His hypothesis simply is that running is what makes us uniquely human and that running allowed our brains to grow.

The basic argument goes as follows. Humans have developed some specific features that allowed them to be skilled endurance runners such as: 

1. Early humans first showed “springy” feet (an arched foot, long Achilles tendon, closely packed bones in the foot and short toes) that allow for the return of energy from the impact of landing to push off and thereby reduce the energy cost of running
2. They also developed various mechanisms for stabilizing the head during running to counteract the significant vertical forces – you can easily observe these forces when running behind someone with a ponytail which is bobbing up and down while the head is perfectly stable
3. In addition, they had a slim torso, a narrow waist but wide shoulders and short arms – not very good for climbing trees but excellent for the necessary counter rotation of the head, arms and pelvis versus the trunk when running
4. They grew big muscles on the butt (despite them not being of much use in walking)
5. And very importantly, early humans developed superior temperature regulation by having sweat glands all over the body and a slim and naked torso which allows them to run even when it is hot

As a result, early (and current) humans can run for a long time at speeds that require four-legged animals (like the gazelle we would like to hunt) to have to gallop. Usually, quadrupeds cool down by panting as they lack sweat glands. Galloping though does not allow animals to pant and so they overheat if they have to gallop for extended times. 

Which leads us to persistence hunting, a form of hunting up until very recently still practiced by some indigenous populations like the Kalahari in Southern Africa. A group of people try to jointly outrun an animal preferably in  the middle of the day when it is particularly hot. The animal needs to rest to cool down but is tracked down again by the hunters who keep chasing it until it collapses from heat exhaustion (usually after the runners have covered a distance anywhere from a half-marathon to a marathon) and the hunters can easily kill the animal even without sophisticated tools or weapons. 

If indeed early humans were able to use their running skills to kill animals they could eat its meat. Meat has a much higher energy density than a pure plant based diet which in turn allowed brains to grow. Brains are expensive organs to maintain as they use a constant and high amount of energy independent of activity even when we are resting.

Therefore, having a more energy rich diet meant that we could afford a bigger brain that uses up this energy. As a consequence, it is easy to see how running started the feed-forward cycle of brain growth that was to follow over the next 2 million years. 

Indeed, you can still try persistence hunting at home (even if I would not recommend it) — Michael Baughman, an avid outdoors enthusiast and runner in 1978 wrote an article for Sports Illustrated about running down a deer close to his home in Oregon. When interviewed years later on his pursuit, he neatly summarized all the characteristics about this most ancient of human pursuits referring to the advantage of an open landscape (just like the African Savannah of our ancestors) for tracking the animal which outruns you on shorter distances as well as the advantage of the heat which we can take much better than the animal:

The country I did it in was quite open, with occasional willow thickets and fairly gentle hills. It was almost always possible to see for hundreds of yards. Deer are like sprinters, and a conditioned distance runner should be able to exhaust one if the country is open enough. It took about four hours, and I estimate I ran about 15 miles. It was also about 80 degrees on that day, which probably helped because deer do not do well in the heat.

For today’s runners, there are a few key lessons to learn from our ancient relatives:

1. What is good for our survival in evolutionary terms usually feels good as well – that is why easy running gives so much pleasure 
2. There is an intimate connection between endurance running and cognitive performance – given how difficult it is to track an animal when doing persistence hunting, running sharpens the mind and leads to better thinking (not only a stronger heart)
3. Also, do not be afraid to take a break and walk (some call it extensive interval training) – while there is something magical about the long-distances our ancestors ran, they did so while taking frequent walking breaks to relocate the animal and probably ran at no more than 70% of full capacity when hunting (and at very different speeds than when running away from a lion). Also, they usually did not run on consecutive days but only for 1-4 days a week. So do not feel bad about taking a walking break when running (especially if you are an older runner of today as taking a walking break greatly helps recovery) and do not forget to take your days off
4. Last but not least, running always used to be a social activity as these persistence hunters never hunted alone. Enjoy going for a run with your friends (and do not only sign up for an app that pretends to replace those social aspects), find a training partner, sign up for a running event or even better organize one yourself.