POSTED 17 MAY 2007
The 5 W's of the people of the fire
WHO used fire among
Eventually, just about everybody. "I can't think of any humans who do not have fire," says Sissel Schroeder of the University of Wisconsin-Madison. By her estimate, archaeological evidence indicates the invention was widespread among our human ancestors by 125,000 years ago.
The question "who invented fire?" may mask the reality: Many people may deserve credit, Schroeder says. "We know a lot of major innovations happened multiple times. Agriculture, writing, and ... just about every other invention arose multiple times in different places."
Richard Wrangham, a primatologist at Harvard University, considers the use of cooked food to be "a human universal." The human digestive system, he says, is "adapted to using processed food, cooked food. We do very poorly without it."
Call us the people of the fire...
WHY use fire?
Control of fire may be the first human invention, and arguably the most useful. Fire was a key to survival, says archeologist Robert Goodby. "Fire gives us instant dominance over all other animals, just because they fear fire. We have plenty of evidence, that before 1.5 million years ago, early hominids were being eaten all the time by big cats and other predators. That pretty much stops when you have fire."
Fire was used across large parts of North America to smoke hides for preservation, says Schroeder. Fire provided light at night and heat for gatherings. Plains Indians used it to burn off underbrush so hunters could spot prey. Fires fired ceramics, and the first leak-proof containers were fired in Japan 12,000 to 13,000 years ago for storing food and water. For archeologists, ceramics, like the metal artifacts that were also born in fire, became a key means for understanding the dates and trading relationships of ancient peoples.
Fire was used for smelting metal (reducing the oxide in ore to pure metal): starting with lead (around 8,500 years ago), copper (more than 7,000 years ago), then iron (more than 3,000 years ago). Fire was also used to cast and forge metals into weapons, tools and adornments. Metal-working so revolutionized society that major eras of human culture and history (the copper, bronze and iron ages) were named after the widespread use of specific metals.
And hundreds of thousands of years before the first smelters, fire was used for cooking. This is not mainly a matter of taste: For all we know, the scent of raw mastodon was then as captivating as the aroma of a juicy cheeseburger is today. More importantly, heat changes food chemically, making more nutrients available. Wrangham says studies indicate that starchy foods provide 20 percent to 60 percent more calories after cooking; and protein availability in eggs increases by about 50 percent.
To break down the stout collagen fibers in raw meat, you'd have to chew it for hours, Wrangham wrote (see #1 in the bibliography). (Sample McArcheoDonald's slogan: "I'm chewin' it. Still chewin' it..."). Overall, Wrangham says. "There is substantial evidence that a key benefit we get from cooked food is the increase in net calories. It's striking that humans actually eat less food than other primates, but have a greater daily energy expenditure, and that is because of cooking."
Wrangham insists that cooking has become a necessity: Humans cannot survive on raw food alone. Even modern people, who do not face the energy demands of a hunter-gatherer, lose weight on a diet of 100 percent raw food, and many women cease menstruating, considered a sign of starvation.
Having more calories available, Wrangham says, fuels energy-hog organs like the brain. Cooking also allows mothers to feed their babies softened food, which allows faster weaning -- and a quicker pregnancy for the mother. Cooking, therefore, can fuel population growth both directly and indirectly.
WHEN was fire tamed?
The question is simple, but the answer is complex and contentious. The oldest solid archeological evidence for controlled fire dates back 125,000 to 230,000 years, says Schroeder. The 230,000-plus site in southwest Europe, called Terra Amata, "has hearths located within shelters which are hard to identify, but are sometimes put forward as an early case of cooking," she says. Several conclusive sites in Europe and the Near East date to 125,000 years ago. These sites contain burned stones typical of hearths, charred bones and sometimes even ash. Most of these hearths are in caves, Schroeder adds, where preservation was more complete than in open-air sites like Terra Amata.
But the absence of evidence is not necessarily evidence of absence, and Wrangham approaches the "first fire" question from a different set of facts. Why, he asks, did the brains, heads and bodies of our Hominid ancestors jump in size about 1.9 million years ago?
Wrangham, a primatologist, starts his answer by pointing to a subtle difference in the diet of chimpanzees and gorillas. Both animals eat fruit, but only gorillas can subsist if necessary on leaves and stems alone. Nevertheless, he says this subtle distinction in diet accounts for huge physical and social differences between the two primates.
So if an almost trivial dietary distinction has major effects, what should we expect from the large-scale dietary changes wrought by cooking, which made new foods available and existing ones more useful? To Wrangham, these massive changes should be reflected by a massive change in our ancestors' bodies: "You would think the impact of cooking would be enormous."
But the last broad change in hominid structure occurred about 1.9 million years ago, he says, long before the first documented fire. "We humans remain essentially the same size and have the same sexual dimorphism [size difference between the sexes]. ... None of this correlates with the archeological evidence about fire."
Wrangham says the conundrum can have two solutions: "Either there is a massive biological problem: Why fire came in 200,000 or 300,000 years ago without affecting us. Or there is a big archeological problem: Why don't we see much evidence for fire before that time? For me, it is much easier to explain the loss of fire evidence than the contradiction of the biological evidence."
At that point, the Playstation/George Foreman Grill cannot be far behind!
HOW were fires made? HOW did
they learn to cook?
Before matches or butane lighters, most people probably started fires through friction: They assembled some tinder and rubbed a hard stick against a soft one, or used a bow to spin one stick against another. Other possible sources of early fire included lightning, and flames at natural gas vents in the Earth
In the old days, fires were difficult to start, and many ancient peoples likely kept them lit, says Neil Whitehead, a professor of anthropology at University of Wisconsin-Madison, who studies the Caribbean and Latin America. For people who lived in one place, "What is so interesting is that you might picture some fires as going on for a very, very long time. In the house, they almost never go out, and in some temples they never go out."
Those old enough to recall President John F. Kennedy probably know that his grave is marked by an eternal flame, to emphasize the significance of his life and help assuage the national grief over his assassination.
Photo: Arlington National Cemetery
The need to feed fires may have contributed to vast social changes, says Schroeder. "Fire created a physical locality where people could gather, but it also required the continued investment of people in sustaining it, caring for it. That meant cooperation, sharing labor. Fire had a lot of things that would bring people together and cement their relationship." Indeed, she notes that early anthropologist Louis Henry Morgan "argued that the hearth was the nexus point for the development of family."
Photo: Library of Congress
And how did our ancestors invent cooking? Schroeder admits there is no incontrovertible evidence for how the first chefs got cooking, but she suggests that early humans emulated the animals they observed so closely. Predators like falcons and eagles, she says, "are some of the first animals to appear at sites of [natural] fires," where they have learned to expect a reliable supply of prey. Early humans, curious what the birds were eating, would "find food that had been naturally cooked as the fire burned down. If they had the brain capacity to piece these patterns together, they might make the connection, 'Oh, this taste, flavor, the smell of these burned animals and plants... Burning does this, maybe we can begin to experiment.'"
WHERE were fires made?
Firepits may be found in the open, but those found inside caves are better preserved, and indeed, the light of the fire would have "made it possible for people to inhabit the deep recesses of caves, and be productive, to make tools," says Schroeder. Cave fires may not have been too smoky, she adds. "We do find cave sites with hearths, so depending on the kind of cave, there probably was enough ventilation in some of them. Fire extended the range of places people could live and work."
(And also when they could work. Fires were a major improvement on moonlight, and whether you wanted to process food, fabricate tools, or make clothes, firelight was the place to just do it.)
As mentioned, fire was used by pre-modern people pretty much across the globe. May we say this incredibly useful technology spread like, er, wildfire?
So what: WHY this
interest in fire?
Fires fascinate for many reasons. They were, says Goodby, a natural hangout: "With fire, you can cook, you have heat, and ... you get smoke to help keep the bugs down. So the hearth is a natural social focus."
Courtesy Robert Goodby, Department of Anthropology, Franklin Pierce College.
And that focus makes hearths and the things found near them all the more fascinating to archeologists. Even though archeology is better for documenting material culture than behavior, finds associated with hearths may still offer clues to how our ancestors acted. For example, a New Hampshire hearth from 3,300 years ago was surrounded by hundreds of stone flakes, a common waste left from the chipping process used to shape arrowheads and other stone tools. Oddly, the stone flakes were too soft for tools, says Goodby, but they were made from a type of stone that fractures much like good tool-stone.
The discovery, Goodby says, had one reasonable explanation: "I concluded this was great stuff for kids to practice on. They got all this experience without wasting the valuable stone, which is rare up here." If you buy his conclusion, you see how the archeological record can show evidence of learning -- a classic human activity.
Perhaps the ultimate reason to study ancient fire is to understand how cooking has changed us. Cooking, simply, makes more nutrients available. Despite the craze for raw food, common sense and our own eyes tell us that virtually everybody cooks the staples: meat, rice, corn, wheat, even many vegetables.
Wrangham says our digestive apparatus has evolved to eat cooked food. The evidence, he says, "probably means our guts are now too small to allow us to survive on raw food, and too high a proportion of the gut is devoted to absorption rather than fermentation." In other words, too much small intestine, not enough large...
Why does outdoor fire retain its allure?
Megan Anderson, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David Tenenbaum, feature writer; Amy Toburen, content development executive