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Did our stone-age ancestors chase down antelope across the hot, dry
savanna, armed with nothing but maybe some blunt sticks or rocks, for
hours on end, never letting the animals rest until they collapsed with
exhaustion, and the hunters, glistening with perspiration, could go in
for the kill?
Probably not.
The idea of ancient humans as persistence hunters, possessed of
superior physical capability, has a certain romance about it and has
become very popular with running enthusiasts. Some scientists suggest it
can explain several of the evolutionary traits humans have acquired
over the past two million years. There may be some groups who practice
it even today, though that’s hotly debated.
Despite the idea’s
foothold in popular culture, however, there is no hard evidence that
ancient humans were persistence hunters, much less that persistence
hunting shaped evolutionary traits. In fact, what evidence there is
doesn’t support the notion that early humans acquired their meaty meals
through feats of running endurance; it flatly contradicts it.
The theory that persistence hunting played a crucial part in the evolution of man was first suggested in 1984 by David Carrier,
who at the time was a doctoral student at the University of Michigan.
Carrier's idea was based on the observation that man is one of the only
mammals that cools itself by sweating. Most four-legged mammals pant to
cast off heat, which doesn't work nearly as well when running. Carrier
concluded that if our early human ancestors could chase an animal long
enough, the animal would overheat and collapse with heat exhaustion, and
the humans could step up and dispatch it easily.
Carrier's idea
was picked up and advanced by the Harvard paleoanthropologist Daniel
Lieberman. "As for anatomical, genetic, and paleontological evidence,
there are so many derived features of humans that make us good at
running and which have no other function, they clearly indicate humans
were selected for long distance running," Lieberman wrote in an email.
He has noted that those features—arched feet, short toes, wide shoulders, long Achilles tendons—seem to have originated around two million years ago, around the time when the genus Homo
evolved and our ancestors began making meat a regular part of their
diet. Persistence hunting, he's argued, might have been the evolutionary
driver.
Eventually, Lieberman's ideas came to the attention of the popular author Christopher McDougall, who wrote about the theory in "Born to Run,"
his bestselling 2009 book about endurance running. McDougall argued
that the features identified by Lieberman explain why we like to run
marathons, even ultra-marathons, and are fairly good at it. When we run
distances, he implied, we are fulfilling our biological destiny. The
running community, and the public generally, have embraced this idea
wholeheartedly.
But the idea is a supposition. It was formulated
as a way to explain characteristics humans possess. The best evidence
for humans engaging in persistence hunting is merely that we have
physical traits that suggest we could do so.
Henry Bunn, a
paleoanthropologist from the University of Wisconsin-Madison, has said
more than once that a person would have to be “incredibly naïve” to
believe the persistence hunting theory. Bunn recalls that he first heard
discussion of the theory at a conference in South Africa, and he
realized almost immediately that if you are going to chase an animal
that is much faster than you, at some point it will run out of sight and
you will have to track it. Tracking would require earth soft enough to
capture footprints and terrain open enough to give prey little place to
hide and disappear.
When he heard of the idea, Bunn had just been
in the Great Rift Valley of East Africa, one of the areas where it is
thought that Australopithecus, our first upright walking
ancestor, evolved into the first of the human genus. He knew the terrain
was probably not soft during the time period discussed by the
persistence hunting theory. And it was mixed savanna woodland, not open
plain. It's highly unlikely that primitive humans would have been
sophisticated enough to track under those conditions, Bunn and his
co-author, Travis Pickering, also of the University of Wisconsin, argued in their first paper questioning the persistence hunting theory.
Plus,
Bunn had spent time with the Hadza, a modern-day group of people in the
Great Rift Valley who are thought to live much like their ancient
ancestors did. The only time Bunn ever knew the Hadza to run was when
they were fleeing pelting rain, angry bees, or marauding elephants—and
maybe occasionally to scavenge.
Bunn and Pickering also knew there
was relevant fossil evidence: a pile of bones from the very time period
in question—1.8 million to 2 million years ago—found in the Olduvai
Gorge in Tanzania. The bones were discovered by Mary Leakey, the same
archeologist who, with Louis Leakey, found a 1.8 million year old
hominid jawbone that was once touted as the "missing link"
between apes and humans. The pile contained bones of ancient waterbuck,
antelope, and wildebeest that had been gathered by an early Homo group for butchering and sharing among them. Some of the bones had marks where rock choppers were used to cut the meat off.
Bunn
recognized a golden opportunity. “We don’t usually get such clear-cut
evidence to test something from 2 million years ago,” he said. He and
Pickering thought that if they could age the different animals in that
collection, they could glean whether the animals were scavenged,
persistence hunted, or hunted some other way. If the animals had been
scavenged or captured by persistence hunting, they likely would have
been either very young or very old. Savanna predators like lions and
leopards don’t chase the healthiest, fastest animals of a herd—and
presumably persistence hunters wouldn’t either. Rather, they’d chase the
ones that are easiest to catch.
But the researchers found
that most of the animals in the collection were either young adults or
adults in their prime. Of the 19 animals they could identify, only four
were very young or old.
To Bunn and Pickering, that suggested the
animals hadn’t been chased down. And because there were butchering marks
on the bones with the best meat, it was also safe to assume that animal
carcasses hadn’t been scavenged by humans after being killed by other
predators; the predators surely would have taken the prime portions for
themselves.
Instead, Bunn believes ancient human hunters relied
more on smarts than on persistence to capture their prey. In his paper
with Pickering, he suggests that our ancestors would wait in brushy,
forested areas for the animals to pass by. They may have even hidden in
the branches of trees, since hooved animals tend not to look up. That
would have allowed the hunters to get close enough to club the animal
with a sharp object.
It’s not entirely clear what that sharp
object would’ve been. Sharpened wooden spears don’t appear in the
archaeological record until about 400,000 years ago, and stone tipped
spears didn’t appear until much later. But this much is clear, Bunn
said: “In terms of the hard, archaeological evidence, persistence
hunting is just flatly contradicted.”
And then there is the horse race.
Back in 1980, two Welsh men
were sitting in the Neuadd Arms Hotel pub in Llanwrtyd Wells, Wales,
arguing about who was faster over long distances, man or horse. Before
the dispute came to blows or bitterness, they decided to settle the
question with an actual race, one of 22 miles. The race was such a
spectacle that it has become an annual event, each year attracting
hundreds of humans and dozens of horses.
Now, there are a number
of reasons why this is an imperfect test of the persistence hunting
theory. Compared with most mammals, for instance, horses are actually
fairly good endurance runners. And Wales is cool, not hot like the
African savanna. But it is also true that the course is intentionally
laid out to give the human the advantage.
So, how many times has a human won?
Twice. In 40 years.
If the prize were a meal, the humans would be starving.
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