Richard Wrangham has tasted chimp
food, and he doesn’t like it. “The
typical fruit is very unpleasant,”
the Harvard University biological anthropologist
says of the hard, strangely shaped
fruits endemic to the chimp diet, some of
which look like cherries, others like cocktail
sausages. “Fibrous, quite bitter.
Not a tremendous amount of sugar.
Some make your stomach heave.”
After a few tastings in western Uganda,
where he works part of the year on
his 20-year-old project studying wild
chimpanzees, Wrangham came to the
conclusion that no human could survive
long on such a diet. Besides the
unpalatable taste, our weak jaws, tiny
teeth and small guts would never be
able to chomp and process enough
calories from the fruits to support our
large bodies.
Then, one cool fall evening in
1997, while gazing into his fireplace
in Cambridge, Mass., and contemplating
a completely different question—“
What stimulated human evolution?”—
he remembered the chimp
food. “I realized what a ridiculously
large difference cooking would
make,” Wrangham says. Cooking
could have made the fibrous fruits,
along with the tubers and tough, raw
meat that chimps also eat, much
more easily digestible, he thought—
they could be consumed quickly and
digested with less energy. This innovation
could have enabled our chimplike
ancestors’ gut size to shrink over
evolutionary time; the energy that
would have gone to support a larger
gut might have instead sparked the
evolution of our bigger-brained, larger-
bodied, humanlike forebears.
In the 10 years since coming on his theory,
Wrangham has stacked up considerable
evidence to support it, yet many
archaeologists, paleontologists and anthropologists
argue that he is just plain wrong.
Wrangham is a chimp researcher, the skeptics
point out, not a specialist in human
evolution. He is out of his league. Furthermore,
archaeological data does not support
the use of controlled fire during the
period Wrangham’s theory requires it to.
Wrangham, who first encountered
chimps as a student of Jane Goodall’s in
1970, began his career looking at the way
ecological pressures, especially food
distribution, affect chimp society. He
famously conducted research into
chimp violence, leading to his 1996
book Demonic Males. But ever since
staring into that fire 10 years ago, he
has been plagued with thoughts of
how humans evolved. “I tend to think
about human evolution through the
lens of chimps,” he remarks. “What
would it take to convert a chimpanzeelike
ancestor into a human?” Fire
to cook food, he reasoned, which led
to bigger bodies and brains.
And that is exactly what he found
in Homo erectus, our ancestor that
first appeared 1.6 million to 1.9 million
years ago. H. erectus’s brain was
50 percent larger than that of its predecessor,
H. habilis, and it experienced
the biggest drop in tooth size in
human evolution. “There’s no other
time that satisfies expectations that
we would have for changes in the
body that would be accompanied by
cooking,” Wrangham says.
The problem with his idea: proof is
slim that any human could control
fire that far back. Other researchers
believe cooking did not occur until
perhaps only 500,000 years ago. Consistent
signs of cooking came even later,
when Neandertals were coping
with an ice age. “They developed earth
oven cookery,” says C. Loring Brace,
an anthropologist at the University of
PALEOANTHROPOLOGY
RICHARD WRANGHAM
FLAME ON : Argues that the practice of cooking
food, beginning with Homo erectus, ultimately
enabled the human brain to evolve to its current
large size.
INTO THE FRYING PAN : His theory has many
skeptics because only scattered signs of fire use
by H. erectus exist. One example: a Chinese site
where H. erectus may have spat hackberry seeds into
early campfires (producing spectacular sparks).
ON THE IMPORTANCE OF THE STOVE : “Everywhere,
everyone expects a cooked meal every evening.”
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