HOMININS, HOMO ERECTUS AND COOKING

HOMININS AND COOKING

Some scientists suggest that fire may have been tamed as early as 1.8 million years ago based on the theory that Homo erectus needed to cook food such as tough meat, tubers and roots to make them edible. Cooked food is more edible and easy to digest. It takes a chimpanzee about an hour to absorb 400 calories from eating raw meat. By contrast it takes a modern human only a couple minutes to wolf down the same amount of calories in a sandwich.

Cooked food is more edible and easy to digest. It takes a chimpanzee about an hour to absorb 400 calories from eating raw meat. By contrast it takes a modern human only a couple minutes to wolf down the same amount of calories in a sandwich.

Some scholars have speculated that the invention of fire turned men from solitary eaters into communal ones. Cooking was a great advancement. With softer, meat, hominins could dispense with their heavy, grinding teeth and extensive guts (modern human intestines occupy a fifth of their gut compared to 50 percent in chimpanzee’s). In 1773, James Boswell wrote: “My definition of Man is a ‘Cooking Animal.’”

Ian Sample wrote in The Guardian:“The advent of cooking was one of the most crucial episodes in the human story, allowing our ancestors to broaden their diet and extract more calories from their food. Because it softened food, it also spelled an end to the days of endless chewing. There has been disagreement among experts on the issue. [Source: Ian Sample, The Guardian, August 22, 2011]

Richard Wrangham, a British evolutionary biologist at Harvard, claimed that harnessing fire to cook food was instrumental in the rise of modern humans in his 2010 book “Catching Fire: How Cooking Made Us Human.” Nicholas Mott wrote in National Geographic: “Applying fire to food also softens tough fibers, releases flavors, and speeds up the process of chewing and digesting. The extra nutrition, and the improved eating experience, allowed our prehistoric ancestors to spend less time searching for food—and less time chewing through tough plants for meager caloric reward. Cooking, therefore, gave us both the nutrition we needed to develop large brains and the time we needed to use them for things more interesting than chewing. [Source: Nicholas Mott, National Geographic, October 26, 2012]

According to Discovery.com: “Anthropologists think early humans began using fire to cook foods some 1.8 million years ago. Though the archaeological evidence is sparse, some scientists adopt this time frame and support that cooking may have lifted the energetic constraints that allowed humans to develop larger brains. Cooking meats may have allowed people to preserve food longer as well as save the immune system the trouble of fighting off certain foodborne pathogens that are killed by the cooking process.” [Source: news.discovery.com, November 9, 2011]

Fire and Homo Erectus

Sangiran Homo erectus Diorama Homo erectus learned to control fire about one million years ago. Some scientists speculate that early hominins gathered smoldering wood from lighting-ignited fires and used it to cook meat, and perhaps kept the coals burning so they could use the fire repeatedly over a relatively long period of time.

Some scientists suggest that fire may have been tamed as early as 1.8 million years ago based on the theory that Homo erectus needed to cook food such as tough meat, tubers and roots to make them edible. Some even speculate that australopthecines were the first to tame fire. The theory suggests that climate changes around 1.9 million years forced hominins to begin eating food like tubers, which they had hadn't eaten before but started eating then because no other food was available.

Archaeologists consider the emergence of stone tool manufacturing and the control of fire as the two hallmark events in the technological evolution of early humans. While experts agree the origins of stone tools date back at least 2.5 million years in Africa, the origin of fire control has been a prolonged and heated debate.

Although scientists estimate that hominin have been using fire for over a million, it is unclear they started using it on a regular basis, such as for cooking daily meals. According to to Associated Press: “Over the years, some experts have cited evidence of fire from as long as 1.5 million years ago, and some have argued it was used even earlier, a key step toward evolution of a larger brain. It's a tricky issue. Even if you find evidence of an ancient blaze, how do you know it wasn't just a wildfire?”

Richard Wrangham’s Cooking Hypothesis

In 1999, Richard Wrangham, an influential primatologist at Harvard, proposed a theory of human origins called the “cooking hypothesis.” Kenneth Miller wrote in Discover: Wrangham aimed to fill a gap in the story of how early hominins like Australopithecus — essentially, apes that walked upright — evolved into modern Homo sapiens. Evolutionary science shows that our distant progenitors became bipedal 6 million to 7 million years ago. [Source: Kenneth Miller, Discover, December 17, 2013 /+]

Archaeologists believe early hominins evolved bigger brains as they walked, took up hunting and developed more complex social structures. That process led to the emergence of Homo habilis, the first creature generally regarded as human, 2.3 million years ago. Yet H. habilis’ brain was only moderately larger than Australopithecus’, and its body retained many apelike features. No one knows why, just 500,000 years later, a radically more advanced species — Homo erectus — emerged. Its brain was up to twice the size of its predecessor’s, its teeth were much smaller, and its body was quite similar to ours. /+\

“Wrangham credits the transformation to the harnessing of fire. Cooking food, he argues, allowed for easier chewing and digestion, making extra calories available to fuel energy-hungry brains. Firelight could ward off nighttime predators, allowing hominins to sleep on the ground, or in caves, instead of in trees. No longer needing huge choppers, heavy-duty guts or a branch swinger’s arms and shoulders, they could instead grow mega-craniums. The altered anatomy of H. erectus, Wrangham wrote, indicates that these beings, like us, were “creatures of flame.” There was one major problem with this hypothesis, however: Proving it would require evidence of controlled fire from at least 1.8 million years ago, when the first H. erectus appeared./+\

Reasoning Behind Richard Wrangham’s Cooking Hypothesis

Richard Wrangham

L.V. Anderson wrote on Slate.com: “This hypothesis stems from a few modern observations. When you eat cooked food, you have access to many more calories than if you eat the same food raw. There are two reasons: Our digestive systems can extract more calories from a cooked steak (for instance) than a raw steak, and it takes much less energy to cook and eat a steak than to gnaw on a raw one for hours. Access to cooked food means a hominin no longer needs enormous teeth to break down all that raw meat and roughage into swallowable hunks, nor does it need as robust a digestive system to process it all. The combination of more calories and less complicated intestines means more energy can be devote to cogitating—hence H. erectus’ relatively big brains, which suck up a lot of calories. As evidence for his theory, Wrangham likes to point to the fact that modern-day humans can’t thrive on an all-raw diet—raw foodists tend to stop menstruating, precluding reproduction. [Source: L.V. Anderson, Slate.com, October 5, 2012 \~/]

In his book “Catching Fire: Cooking Up a Pot of Civilization”, Jane Black wrote in the Washington Post, Richard Wrangham “argues that cooking, not meat-eating or social interdependence, is what differentiates us from other animals. Almost 2 million years ago cooked food helped a new species, homo erectus, with its large brain and small gut, emerge. And cooking is responsible for the development of agrarian societies, traditional gender roles and division of labor. In short, without a hot dinner, we would still be apes. [Source: Jane Black, Washington Post, July 12, 2009 +++]

“Wrangham is not the first to connect cooking to evolution; Jean-Anthelme Brillat-Savarin, the French gastronomist, suggested as much when he wrote in 1825: "It is by fire that man has tamed Nature itself." But Wrangham draws together previous studies and theories from disciplines as diverse as anthropology, biology, chemistry, sociology and literature into a cogent and compelling argument. +++

“Take the issue of digestion. Wrangham makes the case that our ability to heat food and thereby soften it spares our bodies a lot of hard work. And the calories saved in easy digestion reserve energy for other types of physical and intellectual activity. To understand why, simply consider how you feel after eating a light meal versus a heavy one. That shrimp salad demands less work from your intestines and makes you feel energetic afterwards; the 16-ounce steak makes you want to take a nap while your body attacks and breaks down the meal. The same differences apply to softer, cooked food versus raw, unprocessed food. +++

“Softer food can be eaten more quickly than raw food, and that fact has allowed the human species to reallocate the way it spends its time. In the Western world, men and women each spend an average of five percent of their time chewing, about 36 minutes in a 12-hour day, Wrangham reports. Raw food, in contrast, must be chewed longer. For a human being to eat the same diet as a great ape, researchers estimate that we would have to dedicate 42 percent or five hours simply to breaking down our food. +++

“With more free time, societies developed. Male hunters went farther afield in search of a prize, confident that they could get enough calories in a short time from cooked grains, nuts and berries collected by the community's gatherers. Women were bound to the fire. "Cooking freed women's time and fed their children but it also trapped women into a newly subservient role enforced by male-dominated culture," Wrangham writes. "Cooking created and perpetuated a novel system of male cultural superiority."” +++

Book “Catching Fire: Cooking Up a Pot of Civilization” by Richard Wrangham (Basic, 2009)

Critics of Richard Wrangham’s Cooking Hypothesis

L.V. Anderson wrote on Slate.com: “There’s one problem with Wrangham’s elegant hypothesis: It’s hardly the scientific consensus. In fact, since 2009, when Wrangham explained his theory in the book Catching Fire, several archaeologists have come forward with their own, wildly divergent opinions about what is arguably the oldest intellectual property debate in the world. Who really mastered fire, in the sense of being able to create it, control it, and cook with it regularly? Was it Homo erectus, Neanderthals, or modern humans? [Source: L.V. Anderson, Slate.com, October 5, 2012 \~/]

Wrangham’s theory is elegant, but the archaeological record is a little more complicated. There is definitely evidence of fire around 1.6 million years ago in what is now Kenya. But archaeologists dispute whether this was manmade or natural fire. Further complicating Wrangham’s hypothesis is evidence that hominins may not have brought fire with them when H. erectus moved out of Africa into Europe around a million years ago. If fire was as transformative and beneficial as Wrangham said it was, you’d think our ancestors would have brought it with them when they moved to colder climes—or died out if they were unable to do so.

Nicholas Mott wrote in National Geographic: “ Proponents of raw-food diets don’t prepare their meals at all. Like the gorilla, they simply munch away on raw fruits and vegetables. Why? Some of them believe that heating food over 40 degrees Fahrenheit (4 degrees Celsius) destroys natural enzymes present in plants—molecular structures that help us digest proteins missing in processed foods. Others consider a retrogressive diet more environmentally sound, citing the various problems caused by modern industrial food production and distribution. And some folks simply eat raw foods as a quick way to shed a few pounds. [Source: Nicholas Mott, National Geographic, October 26, 2012]

“But “if you’re healthy, this is a terrible idea,” said Herculano-Houzel. “Sure, you’ll lose weight very fast—you’ll be eating all day and still feel starved.” That’s because the low nutritional yield from raw foods requires massive consumption. In other words, if you want to sustain an active lifestyle, eating raw foods takes time and energy of its own. Besides, said Herculano-Houzel, cooked food simply tastes better. “Even apes, when offered a choice of raw food or spaghetti and meatballs, will take the meatballs every time.”“

Cooking 1.9 Million Years Old?

Based on a studies of tooth sizes and the feeding behaviour of monkeys, apes and modern humans, Harvard scientists suggest that cooking was commonplace among Homo erectus and probably originated early, around 1.9 million years ago.Ian Sample wrote in The Guardian: The scientists “concluded that cooking was commonplace among Homo erectus, and probably originated early in that species' reign, if not before in more primitive humans. "This is part of an emerging body of science that shows cooking itself is important for our biology; that is, we are biologically adapted for cooking food," said Chris Organ, an evolutionary biologist at Harvard. [Source: Ian Sample, The Guardian, August 22, 2011 |=|]

“The researchers began by creating an evolutionary tree of monkeys, apes and modern humans. On to this they added information on how long various species spent feeding. Compared with chimpanzees, our closest living relatives, humans spent remarkably little time eating. Chimps typically spent more than one third of their day feeding, while for humans it was about 5 percent of their waking hours. |=|

“The scientists then added information on tooth sizes to the family tree, and this time they included details of extinct human ancestors and closely related species. The study showed that three species of humans, Homo erectus, Neanderthals (Homo neanderthalensis), and modern humans (Homo sapiens), evolved small molars relatively quickly, which could not be explained by general changes in head and jaw sizes. Instead, the scientists believe the invention of cooking could explain the changes in both tooth size and feeding times. As early humans learned how to cook, they no longer needed large back teeth to chew tough food, or had to spend hours chewing to gain enough calories. Over time, large teeth disappeared from our ancestors, to be replaced with far smaller ones. |=|

“According their report in the US journal Proceedings of the National Academy of Sciences, Homo erectus, which emerged in Africa around 1.9 million years ago, spent 6.1 percent of its time eating. Neanderthals, the authors claim, spent 7 percent of their time feeding. "We think that Homo erectus and Neanderthals were spending about as much of their day feeding as we do, which implies that they were both cooking," Organ said. |More primitive species, such as Homo habilis and Homo rudolfensis, which emerged before Homo erectus and the Neanderthals, spent 7.2 percent and 9.5 percent of their day eating. If the estimates are right, it suggests they may have been less accomplished cooks than Homo erectus and the Neanderthals. |=|

Firm Evidence of Cooking in Israel from 780,000 Year Ago

In November 2022, an Israeli-led group of researchers announced that they had found evidence of cooking in the 780,000-year-old remains of a huge carp-like fish discovered in northern Israel. The previous earliest evidence of cooking dated from about 170,000 BC. [Source: Raffi Berg — BBC News, November 16, 2022]

The BBC reported: The remains of the two-meter (6.5 foot) fish were found at the Gesher Benot Yaaqob archaeological site which spans the River Jordan about 14 kilometers (8.5 miles) north of the Sea of Galilee .Researchers led by Dr Irit Zohar of Tel Aviv University studied crystals from the enamel of the fish's teeth, which were found in large quantities at the site. The way the crystals had expanded was a sign that they had not been exposed to direct fire, but cooked at a lower temperature.

"Gaining the skill required to cook food marks a significant evolutionary advance, as it provided an additional means for making optimal use of available food resources," said Professor Naama Goren-Inbar from the Hebrew University of Jerusalem, who directed the excavation. "It is even possible that cooking was not limited to fish, but also included various types of animals and plants."

The scientists determined that the fish once populated the ancient Hula Lake which existed at the site until it was drained in the 1950s to try to eradicate malaria-carrying mosquitoes. Other archaeological evidence found at the site indicates it was inhabited by groups of hunter-gatherers for tens of thousands of years. The team believe the location of such freshwater areas offers a clue to the route followed by early man on its migration out of Africa to the Levant and further afield.

Did Our Early Ancestors Boil Their Food in Hot Springs?

Some of the oldest remains of early human ancestors — dating to 1.9 million years ago — have been unearthed in Olduvai Gorge. According to a highly speculative MIT press release: A team led by researchers at MIT and the University of Alcalá in Spain has discovered evidence that hot springs may have existed in Olduvai Gorge around that time, near early human archaeological sites. The proximity of these hydrothermal features raises the possibility that early humans could have used hot springs as a cooking resource, for instance to boil fresh kills, long before humans are thought to have used fire as a controlled source for cooking. [Source: Jennifer Chu, MIT News Office, September 15, 2020]

“As far as we can tell, this is the first time researchers have put forth concrete evidence for the possibility that people were using hydrothermal environments as a resource, where animals would’ve been gathering, and where the potential to cook was available,” says Roger Summons, the Schlumberger Professor of Geobiology in MIT’s Department of Earth, Atmospheric, and Planetary Sciences (EAPS).

Ainara Sistiaga, a Marie Skłodowska-Curie fellow based at MIT and the University of Copenhagen, found lipids in sediments deposited 1.7 million years ago in Tanzania that resembled lipids shed found in the hot springs of Yellowstone National Park. The region where the team collected the sediments is adjacent to sites of early human habitation featuring stone tools, along with animal bones. It is possible, then, that nearby hot springs may have enabled hominins to cook food such as meat and certain tough tubers and roots.

Exactly how early humans may have cooked with hot springs is still an open question. They could have butchered animals and dipped the meat in hot springs to make them more palatable. In a similar way, they could have boiled roots and tubers, much like cooking raw potatoes, to make them more easily digestible. Animals could have also met their demise while falling into the hydrothermal waters, where early humans could have fished them out as a precooked meal. “If there was a wildebeest that fell into the water and was cooked, why wouldn’t you eat it?” Sistiaga poses.

Did a Quest for Tasty Food Prompt Cooking and Evolution?

Donna Ferguson wrote in The Guardian: Human evolution and exploration of the world were shaped by a hunger for tasty food — “a quest for deliciousness” — according to two leading academics. Ancient humans who had the ability to smell and desire more complex aromas, and enjoy food and drink with a sour taste, gained evolutionary advantages over their less-discerning rivals. Some of the most significant inventions early humans made, such as stone tools and the controlled use of fire, were also partly driven by their pursuit of flavour and a preference for food they considered delicious, according to the new hypothesis. [Source: Donna Ferguson, The Guardian, March 7, 2021]

“This key moment when we decide whether or not to use fire has, at its core, just the tastiness of food and the pleasure it provides. That is the moment in which our ancestors confront a choice between cooking things and not cooking things,” said Rob Dunn, a professor of applied ecology at North Carolina State University. “And they chose flavour.”

Cooked food tasted more delicious than uncooked food — and that’s why we opted to continue cooking it, he says: not just because, as academics have argued, cooked roots and meat were easier and safer to digest, and rewarded us with more calories. “Having a big brain becomes less costly when you free up more calories from your food by cooking it,” said Dunn, who co-wrote Delicious: The Evolution of Flavour and How it Made Us Human with Monica Sanchez, a medical anthropologist.

However, accessing more calories was not the primary reason our ancestors decided to cook food. “Scientists often focus on what the eventual benefit is, rather than the immediate mechanism that allowed our ancestors to make the choice. We made the choice because of deliciousness. And then the eventual benefit was more calories and fewer pathogens.”

Study of Gorillas Shows Why Cooking Gave Hominins Bigger Brains

Gorillas have to forage and eat for 8.8 hours a day or more. This, scientists suggest, shows how cooking gave humans spare energy for brain growth. Maev Kennedy wrote in The Guardian: Research into these matters “explains why great apes such as gorillas, which can have bodies three times the size of humans, have considerably smaller brains. Though gorillas typically spend up to eight hours feeding, their diet influenced an evolutionary tradeoff between body and brain size; supporting both big bodies and big brains would be impossible on a raw food diet. [Source: Maev Kennedy, The Guardian. October 22, 2012]

“The brain is so energy-hungry that in humans it represents 20 percent of the resting metabolic rate, even though it only represents 2 percent of body mass, suggest Professor Suzana Herculano-Houzel and Karina Fonseca-Azevedo of the Institute of Biomedical Sciences at the Federal University of Rio de Janeiro. "Why are the largest primates not those endowed with the largest brains as well? Rather than evidence that humans are an exception among primates, we consider this disparity to be a clue that, in primate evolution, developing a very large body and a very large brain have been mutually excluding strategies, probably because of metabolic reasons." |=|

“Gorillas, they suggest, already live on the limit of viability, foraging and eating for 8.8 hours a day, and in extreme conditions increasing this to as much as 10 hours a day. In contrast, humans' move to a cooked diet, possibly first adopted by Homo erectus, and their bigger brains yet smaller bodies, left spare energy which allowed further rapid growth in brain size and the chance to develop the big brain as an asset rather than a liability, through expanded cognitive capacity, flexibility and complexity. "We propose that this change from liability to asset made possible the rapid increase in brain size that characterises the evolution of Homo species, leading to ourselves. We may thus owe our vast cognitive abilities to the invention of cooking – which, to my knowledge, is by far the easiest and most obvious answer to the question, what can humans do that no other species does?" Herculano-Houzel commented on the paper, published in the journal PNAS, the Proceedings of the Natural Academy of Sciences of the USA. |=|

“The paper builds on the earlier research by Richard Wrangham, who said he hoped later work would look at tradeoffs within the body allowing energy from smaller organs to be diverted to the brain – for instance our relatively small guts. "Human guts are about 60 percent of the expected size for a primate. The small size of human guts (combined with our having the same basal metabolic rate as any other primate, relative to body mass) means that we have some spare energy, which contributes to explaining how we can afford a relatively large brain. And the reason we have been able to evolve small guts is that we have been able to rely on eating our food cooked."” |=|

Mice Experiment Shows Cooked Meat Provides More Energy Than Raw Meat

Discovery.com reported: “For years, scientists have thought cooked foods are easier to digest, and thus, are more nutritious than non-cooked eats. Before now, though, they lacked the evidence needed to confirm these claims for meat. But a recent experiment suggests that cooked meat packs more nutritional value than its raw counterpart. The findings could give clues to how early humans gained more energy from cooking meats as well as provide insight on ways to maximize nutrition today. [Source: news.discovery.com, November 9, 2011]

“The researchers tested foods in the ways that they’re actually digested in organisms, rather than analyzed outside of the body. The experiment involved feeding groups of mice variations of organic beef or sweet potatoes over a 40-day period. Different diets included raw/intact, raw/pounded, cooked/intact and cooked/pounded foods (either the beef or the sweet potato). Mice could eat food freely, and researchers monitored the rodents’ activity levels and body mass. While activity didn’t differ across groups, body mass did. All mice lost weight on the diets, but those consuming cooked foods lost less than others eating raw foods. This means that the mice were getting more energy from the cooked foods, especially the meat.

“The paper’s authors think a few mechanisms might be at play. First, cooking seems to unwind proteins in meat, which could make it easier to digest in the small intestine before gut bacteria take their share of the pie. In addition, cooking meat seems to loosen muscle fiber connections, making the foods easier to chew. The way foods are prepared — whether they’re pounded, crushed, sliced, and so on — also matters. Pounded foods appeared to provide more energy, but not as much as cooking. Yet while pounding breaks down the structure of food fibers, it doesn’t have as much of an effect on cells at the molecular level. This is where cooking has the advantage. Incorporating both cooking and pounding produced the best results.”

Debate about Which Hominins First Started Cooking

L.V. Anderson wrote on Slate.com: “According to Wrangham, H. erectus must have had fire—just look at their anatomy! H. erectus had smaller jaws and teeth (and smaller faces in general), shorter intestinal tracts, and larger brains than even earlier hominins, such as Australopithecus afarensis, for instance, who were boxier, more apelike, and probably duller. Wrangham argues that H. erectus would not have developed its distinctive traits if the species hadn’t been regularly eating softer, cooked food. [Source: L.V. Anderson, Slate.com, October 5, 2012 \~/]

“If H. erectus didn’t bring fire mastery to Europe, who did? Archaeologists Wil Roebroeks of Leiden University in the Netherlands and Paola Villa of the University of Colorado Museum found evidence for frequent use of fire by European Neanderthals between 400,000 and 300,000 years ago. Roebroeks and Villa looked at all the data collected at European sites once inhabited by hominins and found no evidence of fire before about 400,000 years ago—but plenty after that threshold. Evidence from Israeli sites put fire mastery at about the same time. H. sapiens arrived on the scene in the Middle East and Europe 100,000 years ago, but our species didn’t have a discernible impact on the charcoal record. Roebroeks and Villa conclude that Neanderthals must have been the ones who mastered fire. \~/

“One of the beautiful things about the archaeological record is that archaeologists are always willing to debate about it. Attributing fire to Neanderthals is an overly confident reading of the evidence, according to archaeologist Dennis Sandgathe of British Columbia’s Simon Fraser University. Of course the number of campsites with evidence of fire increased between 1 million and 400,000 years ago, he says—the number of campsites, period, increased during this time in proportion with population growth. But that doesn’t mean the use of fire was universal among European hominins—there are plenty of Neanderthal campsites out there that show little or no evidence of fire, and Sandgathe has personally excavated some of them. What’s more, Sandgathe told me when I asked him about Roebroeks’ and Villa’s data, “We actually have better data than they do when it comes to Neanderthal use of fire.” \~/

“According to Sandgathe and his colleagues, hominins didn’t really master fire until around 12,000 years ago—well after Neanderthals had disappeared from the face of the planet (or merged into the human gene pool via interbreeding, depending on your view). Sandgathe and his colleagues excavated two Neanderthal cave sites in France and found, surprisingly, that the sites’ inhabitants used hearths more during warm periods and less during cold periods. Why on earth would Neanderthals not build fires when it was freezing outside? In “On the Role of Fire in Neandertal Adaptations in Western Europe: Evidence from Pech de l’Aze´ IV and Roc de Marsal, France,” Sandgathe advances the hypothesis that European Neanderthals simply didn’t know how to make fire. All they could do was harvest natural fires—those caused by lightning, for instance—to occasionally warm their bodies and cook their food. (This explains why Sandgathe found more evidence of fire from warm periods: Lightning is far less common during cold spells.) \~/

“Roebroeks and Villa think Sandgathe’s reasoning is flawed: After all, there isn’t evidence of fire at every modern human campsite, either, when you look at sites from the Upper Paleolithic period, which concluded about 10,000 years ago. “However, nobody would argue that Upper Paleolithic hunter-gatherers were not habitual users of fire,” they wrote in a response to Sandgathe et al.’s criticism of their work. Wrangham, meanwhile, thinks both Sandgathe et al. and Roebroeks et al. ignore some critical nonarchaeological evidence: his point that contemporary humans can’t survive on a diet of uncooked food. Accepting Sandgathe’s hypothesis, Wrangham wrote in an email, “means that the contemporary evidence is wrong, or that humans have adapted to need cooked food only in the last 12,000 years. Both suggestions are very challenging!” \~/

Difficulty Studying Early Fire Use and Cooking

L.V. Anderson wrote on Slate.com: “Why on earth can’t scientists agree on whether people mastered fire 1.8 million years ago or 12,000 years ago? That’s a 150-fold difference. Well, figuring out who burned what, when, is not an easy business. For one thing, archaeologists can’t always tell what caused a fire: a volcano, for instance, a lightning strike, or hominin ingenuity. And even if there is clear evidence of hominin fire use—a hearth at a formerly inhabited cave, for instance—it’s almost impossible to tell whether it was created by people from scratch or merely stolen from a natural fire and then transported to a hearth, where it was kept alive as long as possible. Scientists call this kind of fire use opportunistic. [Source: L.V. Anderson, Slate.com, October 5, 2012 \~/]

“What’s more, even when people were creating fires, the evidence of said fires doesn’t always stay put. Ashes have a tendency to blow away instead of embedding themselves neatly in the archaeological record, while water can take evidence of fire from its original location and carry it someplace completely different. Then there’s human error: As Sandgathe et al. write in their discussion of the available evidence, “There are … examples where residues originally interpreted as the remains of fires are later identified as something else.” (I hate it when that happens.) At one site in China, for instance, layers of earth originally believed to be ashes were later revealed to be silt and unburned bits of organic matter. \~/

“Archaeological methods are improving, and they may well end up bearing out Wrangham’s hypothesis. In a paper published earlier this year, archaeologists used advanced techniques (known as micromorphological and Fourier-transform infrared microspectroscopy) to examine sediment and reveal evidence of fire at a million-year-old South African cave site. \~/

“Wrangham is also hopeful that other disciplines will provide evidence for his theory. “I suspect genetics will help,” he says. “If we can pin down the genes underlying the adaptation to cooked food, we may be able to date the control of fire close enough to settle the big question.” “Sure, that would be pretty compelling evidence,” admits Sandgathe. But he’s hopeful that genetics will bolster his hypothesis: that Neanderthals survived frigid glacial periods not because they regularly used fire, but because they had thick body hair. “At some point someone may announce the discovery of the gene or genes that code for thickness of body hair, and so could answer that question,” he says. \~/

“Judging from the way things are going, this debate may rage on for a good while longer. And there is room for more than one right answer: It’s possible that different groups mastered fire independently of one another at different points in time. But laypeople can take comfort in knowing that, even if we don’t know yet who first mastered fire—our simple ancestors almost 2 million years ago, our more advanced cousins 400,000 years ago, or our direct antecedents about 10,000 years ago—there’s no doubt who holds the intellectual property rights to it today. We even put it in an oven and made it our own.” \~/

Cooked Food Versus Raw Food

Ann Gibbons wrote in National Geographic: “The latest clue as to why our modern diet may be making us sick comes from Harvard primatologist Richard Wrangham, who argues that the biggest revolution in the human diet came not when we started to eat meat but when we learned to cook. Our human ancestors who began cooking sometime between 1.8 million and 400,000 years ago probably had more children who thrived, Wrangham says. Pounding and heating food “predigests” it, so our guts spend less energy breaking it down, absorb more than if the food were raw, and thus extract more fuel for our brains. “Cooking produces soft, energy-rich foods,” says Wrangham. Today we can’t survive on raw, unprocessed food alone, he says. We have evolved to depend upon cooked food. [Source: Ann Gibbons, National Geographic, September 2014 /*/]

“To test his ideas, Wrangham and his students fed raw and cooked food to rats and mice. When I visited Wrangham’s lab at Harvard, his then graduate student, Rachel Carmody, opened the door of a small refrigerator to show me plastic bags filled with meat and sweet potatoes, some raw and some cooked. Mice raised on cooked foods gained 15 to 40 percent more weight than mice raised only on raw food. /*/

“If Wrangham is right, cooking not only gave early humans the energy they needed to build bigger brains but also helped them get more calories from food so that they could gain weight. In the modern context the flip side of his hypothesis is that we may be victims of our own success. We have gotten so good at processing foods that for the first time in human evolution, many humans are getting more calories than they burn in a day.”

Image Sources: Wikimedia Commons except Wonderwerk Cave, University of Toronto and Wonderwerkcave.com and Richard Wrangham, Harvard University

Text Sources: National Geographic, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Nature, Scientific American. Live Science, Discover magazine, Discovery News, Ancient Foods ancientfoods.wordpress.com ; Times of London, Natural History magazine, Archaeology magazine, The New Yorker, Time, Newsweek, BBC, The Guardian, Reuters, AP, AFP and various books and other publications.

Last updated April 2024