Human Evolution: Why Did We Start Running?

Human evolution has created our amazing running ability over the course of two or three million years. The question is, why? What possible use could we have for the crown of ultimate long-distance running species on the planet?

Numerous scientists have noted our lack of speed but incredible endurance, and pondered the use of such an ability.

Some, like Harvard Anthropology Professor Daniel Liberman (1), believe we gained our running prowess as a means of filling a unique hunting niche.

Our race only developed bows and arrows around 50,000 years ago, so Liberman argues humans literally started running animals to death, which proved so sucessful that it altered the path of human evolution. We'd start running at a slow but steady pace after an antelope or some other creature, he resons, and though it could easily outrun us , after hours and hours, we'd eventually wear it down and it it would collapse.
Human Evolution Persistence Hunt

It's not a preposterous idea, and there are instances of various isolated aboriginal peoples still conducting these hunts today, though not as a major source of calories. In the heat of the day, humans have a unique advantage: our ability to sweat off our heat. Most animals must rest and pant through the mouth, but as long as we're hydrated and we can sweat, we can keep running.

“Endurance running is part of a suite of shifts that made Homo human,” Lieberman said.

He's probably right, but it's unlikely that hunting ever had more than a tangental impact on human evolution.

Human Evolution: We Were Not Made For Meat Eating

Many anthropologists believe that hunting arose no earlier than 200,000 (2) or 100,000 years ago (3), too recent to have had a major impact on human evolution, and archaeology is on their side.

Fossil teeth belonging to our ancestors found in east Africa suggest a fruit-based diet, and stone tools found at a 1.5 million-year-old site a Koobi Fora Kenya were used to process plant materials, not animal protein (4).

The diet of early man was made up largely of high-fiber vegetables and fruit, as opposed to the modern high fat, animal protein-based diet of today, with its attendant chronic disorders (3).

Yet in his paper, "Endurance running and the evolution of Homo (5)," Lieberman proposes that it may have been access to endurance-hunted meat which gave us the protein needed for the enlargement of our brain, and spurred human evolution to make us the smartest creature on the planet.

There are some problems with this idea, however.

Humans have a body ideally suited for a for fruit eating, and lack all features ideal for procuring and consuming meat.

Dr. Douglas Graham has highlighted numerous characteristics that set us apart from meat eaters. These include, but are not limited to (6):

Claws: We don't have them, which makes tearing meat apart hard.
Teeth: Carnivores have sharp molars, while our are flat for mashing fruits and vegetables. Our canines don't look or act like fangs, nor do we have a mouth full of them.
Jaw: The ability to grind food by moving our jaws laterally is unique to plant eaters. Meat eaters have no lateral jaw movement.
Vison: We can see the full spectrum of color, making it easy to distinguish ripe from unripe fruit. Meat eaters typically do not see in full color.
Sleep: Humans spend about two thirds of every day awake. Carnivores sleep between 18 to 20 hours per day, and sometimes more.
Intestines: Our intestines are 12 times the length of our torso, which allows the slow absorption of sugars and other water-borne nutrients from fruit. In contrast, the digestive tract of a carnivore is three times the length of its torso. Meat tends to rot and ferment in our dank, lengthy intestines.
Carriage: We walk erect. All primary carnivores go on all fours.
Digestive Enzymes: We produce digestive enzymes for fruit digestion such as ptyalin. Meat eaters don't make any ptyalin, and have completely different enzyme ratios.

Also, suggesting that extra protein would spur mental expansion ignores cause and effect.

Muscle magazines will tell you you need huge quantities of protein to build large muscles and maintain energy and health, but science tells us otherwise (7).

No food can build muscle. The body builds muscle when a demand is put on the body. Obviously it needs the building blocks of food, but these are modest needs easily met by plants.

Similarly, even if we have the building blocks, we would need a demand on the brain to spur its growth.

Infants go through the quickest period of growth we experience, and yet are happy to consume one food: their mother's milk, which is a mere 6 percent protein.

In addition, when protein intake rises above 10 percent of calories, especially when it comes from dangerous animal protein, our health begins to decline, and we start developing diseases of affluence which never had earlier on in human evolution (10).

Human Evolution: We Are Fruit Hunters

The exuberant, intelligent and physically inspiring spider monkeys of Panama have long impressed Katharine Milton, a physical anthropologist at the University of California at Berkeley (8).

Compared to the sedate howler monkeys, which eat leaves for most of their calories, spider monkeys feast almost entirely on fruit, and eat only the tips of certain tender greens.

Human Evolution Baobab Fruit

Howlers travel slowly through the canopy on all fours, while spiders swing along like Tarzan, faster than Milton can keep up. She had to hire a local to -get this- run after them.

The spiders’ territory is huge, some 750 acres, ten times that of the howler monkeys, though Milton believes it may be as large as two thousand acres. Their long-distance forays for fruit are astounding.

Within their territory they eat at least 100 species of fruit, and keep track of thousands of fruit-bearing trees. They can recall exactly where these these are, when they're in season, and how best to get to them and back.

Their groups are capable of dividing and subdividing to make sure everyone gets fed, and each was capable of fending for itself. Howlers, on the other hand, tend to stay together, and when trouble strikes, they're confused and timid.

The spiders, with all their teasing and playfulness, their group dynamics, and their complicated understanding of the circumstances, reminded Milton of people, she said.

Human Evolution: The Oportunity Fruit Provided

Some scientists now argue fruit eating and the adaptations necessary for it spurred the incredible minds of our primate relatives (9), while ignoring the idea that it could have done the same for humans. However, recently scientists have begun to consider us primarily fruit eaters (12).

The geologic record of the the Sahara tells a tale of regular shifts between long periods of rain and the the acompanying expansion of the rich African forests, and drier periods when the desert grew, and the forests receded into savanna.

During these periods, our ancestors would have been faced with a choice: retreat south with the forest and decrease, or they venture out into the Sahel savanna region

Traveling from tree to tree was no longer an option on the savanna, yet it was still rich with fruit. We tend to think of savannas in terms of grassy plains, but there are still plenty of trees in many of these regions. The Northern Congolian forest-savanna area is one example.

Baobab fruit, aizen and jackalberry are three examples of fruit that play a critical role in the diets of the people of the savanna regions to this day, and they likely served the same purpose for the speciies in its infancy, when they provided sustance and spurred human evolution.

The fruit was out there, but with the canopy significantly reduced and a layer of grasses growing up to take advantage of the light streaming through, humans venturing there had a lot more to worry about.

If our ancestors wanted to dwell in the new savanna, they would have face the numerous predators which couldn't reach them in their forested homes, forcing them to learn ever-more complicated group dynamics and strategies, just like the spider monkeys. Without the option of swinging from tree to tree, we also required a new way of rapid locomotion between food sources, and that was running.

This, then, was the spur in human evolution that developed our running abilities and put a demand on our brains.

Lieberman argues that our tree climbing ability was lost when we developed our running ability (11), but anyone who has ever scrambled up a tree knows that we retain enough dexterity in that area to make reaching fruit, if not arboreal travel, still easily within our reach.

Padding across the plains in search of fruit lets us take advantage of a new niche and spurred human evolution to make us the best runners on the planet.

I'm no anthropologist, and some may baulk at my fruit hunter theory, but it seems at least as plausible as one that relies on a non existent meat affinity that is contradicted by our very health.

I'm leery of anyone who says they know what humans evolved to do. Our abilities are so flexible that saying we were meant for any one thing seems prepostuerous, yet of all things, gathering fruit seems unavoidable.

Human Evolution: Following Up

Read about the incredible distance running ability human evolution created here.

Read about the healthy raw food diet that mimics what our ancestors ate millions of years ago.

Human Evolution Sources:

(1) Lieberman, Daniel. “Why Humans Run: The Biology and Evolution of Marathon Running,” April 12, 2007 Lecture in the Harvard Museum of Natural History's Geological Lecture Hall.
(2) Binford, Lewis. "Were there elephant hunters at Toorala?"
(3) Zihlman, Adrienne. "Women as Shapers of the Human Adaptation" in "Women the Gatherer." F Dahlberg, Ed.
(4) Binford, Lewis. "Faunal Remains from Klasies River Mouth."
(5) Bramble, Dennis M. Daniel E. Lieberman, "Endurance running and the evolution of Homo." Nature, 18 November 2004
(6) Graham, Dr. Douglas N., "The 80/10/10 Diet". 2006.
(7) Perlot, Andrew. "Vegetable Protein Is All You Need".
(8) Radetsky, Peter. "Gut Thinking" Discover. May 1995.
(9) Emmanuelle Normand, Simone Ban, Christophe Boesch. "Forest chimpanzees (Pan troglodytes verus) remember the location of numerous fruit trees." Animal Cognition. 31 May 2009
(10) Campbell, T. Colin. "The China Study." 2006.
(11) Hadzipetros, Peter. "Q&A :Harvard anthropologist Daniel Lieberman on why humans run." CBC News. 11 April, 2007.
(12) Dominy, Nathaniel J. “Fruits, fingers, and fermentation: The sensory cues available to foraging primates”, Integrative and Comparative Biol, 44 (4): 295-303, 2004.

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