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?
scientists have noted our lack of speed but incredible endurance, and
pondered the use of such an ability.
Harvard Anthropology Professor Daniel Liberman (1), believe we gained
our running prowess as a means of filling a unique hunting niche.
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.
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.
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,”
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
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).
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
its attendant chronic disorders (3).
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
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):
We don't have them, which makes tearing meat apart hard.
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.
The ability to grind food by
moving our jaws laterally is unique to plant eaters. Meat eaters have
no lateral jaw movement.
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.
Humans spend about two thirds of every day awake. Carnivores sleep
between 18 to 20 hours per day, and sometimes more.
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
walk erect. All primary carnivores go on all fours.
Enzymes: We produce digestive enzymes for fruit digestion such
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.
magazines will tell you you need huge quantities of protein to build
large muscles and maintain energy and health, but science tells us
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
Similarly, even if we have the building blocks, we would need a demand
on the brain to spur its growth.
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
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
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).
to the sedate howler monkeys, which eat leaves for most of their
calories, spider monkeys feast almost entirely on fruit, and
only the tips of certain tender greens.
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.
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
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.
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
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
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
from tree to tree was no longer an option on the savanna, yet it
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
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.
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
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
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.
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,
:Harvard anthropologist Daniel Lieberman on why humans run."
CBC News. 11 April, 2007. (12) Dominy,
Nathaniel J. “Fruits, fingers, and fermentation: The sensory cues
foraging primates”, Integrative and Comparative Biol, 44
(4): 295-303, 2004.
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