HOMININS, HOMO ERECTUS AND FIRE

FIRE AND HOMO ERECTUS

Sangiran Homo erectus Diorama Homo erectus is believed to have learned to control fire about one million years ago. Some scientist speculate that early hominids 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. University of Toronto anthropologist Michael Chazan said: "The control of fire would have been a major turning point in human evolution. The impact of cooking food is well documented, but the impact of control over fire would have touched all elements of human society. Socializing around a camp fire might actually be an essential aspect of what makes us human."

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. Francesco Berna of Boston University told Archaeology magazine: learning to use fire was an important turning point for our species — both evolutionarily and culturally. "Control of fire is a tool for adapting to different environments," he says. "It provides warmth, it provides light...and it keeps away wild animals." [Source: Zach Zorich, Archaeology magazine, July-August 2012]

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?”

Does Eating Cooked Food Mean That Hominins Controlled Fire

Zach Zorich wrote in Archaeology: “Some paleoanthropologists believe that people have been eating cooked food, and therefore making fires, for millions of years. The evidence for this, so far, has been evolutionary changes in hominin skeletons, such as decreasing tooth and jaw sizes. But there has been very little direct archaeological evidence of fire use prior to 700,000 years ago.” [Source:Zach Zorich, Archaeology, Volume 65 Number 4, July/August 2012]

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.

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]

Evidence of Fire and Homo Erectus

Francesco Berna of Boston University and a multinational team of researchers have uncovered evidence that Homo erectus was using fire about one million years ago at Wonderwerk Cave in South Africa. According to Archaeology magazine: “Using a technique that allows researchers to conduct microscopic analysis of the chemical composition of a sample, Berna was able to identify burned pieces of bone and plant material in the cave's sediments. The sediment came from an excavation unit that is roughly 100 feet inside the cave, which makes it unlikely that the material was burned by a lightning strike or wildfire. According to Berna, learning to use fire was an important turning point for our species — both evolutionarily and culturally. "Control of fire is a tool for adapting to different environments," he says. "It provides warmth, it provides light...and it keeps away wild animals." [Source: Zach Zorich, Archaeology magazine, July-August 2012]

Evidence of very old fires backing up the theory mentioned above include thermally altered stone artifacts and circles of burned clay that have been dated to between 1.5 million and 1.7 million years ago. Charred animal bones found in Swartkrans cave near Pretoria have been dated to 1.5 million years. Swartkrans is home to an abundance of stone and bone tools dating back almost two million years as the source of 270 burned bones estimated to be more than one million years old. These bones may be evidence of the earliest known controlled fires. [Source: Erin Wayman, Smithsonian Magazine, January 2012]

The oldest largely accepted evidence of fire used by “Homo erectus” are burned animals bones found among remains of “ Homo erectus” in the same caves in Zhoukoudian, China where Peking man was found. The burned bones have been dated to about 500,000 years old. In Europe, there is evidence of 400,000-year-old, hominin-made fires. Critics argue that the charred animal bones could simply be the remains of bones in naturally occurring fires. Studies of the ashes in Zhoukoudian indicate they may have been produced by natural causes and washed into the cave. Anthropologists who study hunters and gatherers say that fires made by these people are small and leave little evidence.

20120202-Caune de Arago.jpg
Caune de Arago

The earliest really hard evidence of fire comes in the form of stone hearths and clay ovens made in the last 250,000 years by archaic humans. Human control of fire is well documented at sites dating from 150,000 to 200,000 years ago, and remains of hearths between 300,000 and 400,000 years old have been found at a handful of sites in France, Hungary, and China. In 1997, archaeologists from Liverpool University announced they found what may be one of Europe's oldest hearths at a 400,000-year-old Stone Age site in southeastern England. The find consisted of an area of red, baked sediments, whose limited expanse suggests a controlled fire rather than a natural one. The burnt sediments have been removed intact as part of a one-cubic-meter block so laboratory tests can be undertaken to help identify the nature of the burning. [Source: Archaeology magazine, Theresa A. McGill, November/December 1997]

The site, near Bury St. Edmunds in Suffolk, was in a favorable spot near a source of water. According to John Gowlett, who is directing the excavation, it seems to have been used over centuries during a lull between the Ice Ages, when numerous large mammals, including bear and deer, undoubtedly hunted by early humans, were found in the area. Thousands of flint flakes have been discovered at the camp, the by-products of stone tool manufacturing, and many have been matched to the cores from which they were struck.

Evidence of Hominin Fire Use 1 Million Years Ago at at Wonderwerk Cave in South Africa

Wonderwerk Cave

Francesco Berna of Boston University and a multinational team of researchers have uncovered evidence that Homo erectus was using fire about one million years ago at Wonderwerk Cave in South Africa. According to Archaeology magazine: “Using a technique that allows researchers to conduct microscopic analysis of the chemical composition of a sample, Berna was able to identify burned pieces of bone and plant material in the cave's sediments. The sediment came from an excavation unit that is roughly 100 feet inside the cave, which makes it unlikely that the material was burned by a lightning strike or wildfire. [Source: Zach Zorich, Archaeology magazine, July-August 2012]

Ash and burnt bone samples found at South Africa's Wonderwerk Cave — a massive cave located near the edge of the Kalahari — suggest fires were frequently burned there. Research associated with that site makes "a pretty strong case". Berna presented the work with colleagues in the Proceedings of the National Academy of Sciences. [Source: Malcolm Ritter, Associated Press, April 4, 2012 ~]

Malcolm Ritter of Associated Press wrote: One expert said the new finding should be considered together with a previous discovery nearby, of about the same age. Burnt bones also have been found in the Swartkrans cave, not far from the new site, and the combination makes a stronger case than either one alone, said Anne Skinner of Williams College Another expert, Wil Roebroeks of Leiden University in The Netherlands, said that while the new research does not provide "rock solid" evidence, it suggests our ancestors probably did use fire there at that time. ~

“The ancestors probably brought burning material from natural blazes into the cave to establish the fires, said Michael Chazan of the University of Toronto, a study author. Stone tools at the site suggest the ancestors were Homo erectus. The scientists didn't find signs of fire preparation, like a hearth or a deep pit. But Berna said it's unlikely the fires were simply natural blazes, such as from lightning strikes. That's because the evidence shows repeated fires burned deep inside the cave, he said. The cave entrance is almost 100 feet away, and because of changes in the cave over the past 1 million years, the entrance was apparently even farther away when the fires burned, he said. In contrast, he said, the bones at Swartkrans could have been burned by a natural fire in the open before winding up in that cave. ~

“The scientists also found no sign that the Wonderwerk cave fires were ignited by spontaneous combustion of bat guano, which they called a rare but documented event. Berna and colleagues describe animal bones that show discoloring and a chemical signature of being heated. They also report microscopic bits of ash in excavated dirt from the cave, indicating burning of light material like leaves, grasses and twigs. And they found evidence of heating in samples of fractured stone. Several lines of evidence suggest the material was heated within the cave rather than blown or washed in from outside. It's not clear what the fires were used for. While the burnt bones suggest cooking, the ancestors might have eaten the meat raw and tossed the bones into the fire, Berna noted. Other possible uses might be warmth, light and protection from wild animals, he said. ~

“In a statement to The Associated Press, Roebroeks and Paola Villa of the University of the Witwatersrand in Johannesburg, South Africa, and the University of Colorado Museum in Boulder, said that while the new study probably demonstrates use of fire, they'd like to see signs of preparations like a hearth to be sure. In any case, they said, the work does not show that human ancestors were using fire regularly throughout their range that long ago. In a paper published in 2011, they traced such habitual use of fire to about 400,000 years ago.” ~

Research at Wonderwerk Cave

On how the discovery of fire use at Wonderwerk Cave took place, Kenneth Miller wrote in Discover: “Like many archaeological discoveries, this one was accidental. Researchers weren’t looking for signs of prehistoric fire; they were trying to determine the age of sediments in a section of the cave where other researchers had found primitive stone tools. In the process, the team unearthed what appeared to be the remains of campfires from a million years ago — 200,000 years older than any other firm evidence of human-controlled fire. Their findings also fanned the flames of a decade-old debate over the influence of fire, particularly cooking, on the evolution of our species’s relatively capacious brains. [Source: Kenneth Miller, Discover, December 17, 2013 /+]

“At Wonderwerk, Boston University archaeologist Paul Goldberg — a specialist in soil micromorphology, or the small-scale study of sediments — dug chunks of compacted dirt from the old excavation area. He then dried them out and soaked them in a polyester resin so they would harden to a rocklike consistency. Once the blocks solidified, researchers sawed them into wafer-thin slices. The “eureka” moment came later, as the slices were examined under a microscope at Israel’s Weizmann Institute. “Holy cow!” Goldberg exclaimed. “There’s ashes in there!”/+\

“He and his colleagues saw carbonized leaf and twig fragments. Looking more closely, they identified burned bits of animal bones as well. The bones’ sharp edges, and the excellent preservation of the plant ash, indicated that neither wind nor rain had ushered in the burnt material. The burning clearly had occurred inside the cave./+\

“Then team member Francesco Berna subjected the sample to a test called Fourier transform infrared microspectroscopy (FTIR), which analyzes a material’s composition by measuring the way it absorbs infrared waves. Often used in crime labs to identify traces of drugs and fibers, FTIR can also determine the temperature to which organic matter has been heated — and Berna is among the first to adapt it for archaeology. When he ran an FTIR analysis on one of the sediment slices, the sample’s infrared signature showed that the cave material had been heated to between 750 and 1,300 degrees Fahrenheit. That was just right for a small fire made of twigs and grasses.” /+\

Quest for Evidence of the Earliest Fire

Wonderwerk Cave

Kenneth Miller wrote in Discover: “The clues indicating early use of fire tend to be subtle; it’s easy to miss them, but it’s also easy to see them when they’re not really there. What looks like charring on a rock or bone, for example, often turns out to be staining from minerals or fungus. And high-tech analytic techniques don’t always banish the ambiguity. [Source: Kenneth Miller, Discover, December 17, 2013 /+]

“In recent decades, a number of sites have vied for the title of earliest human-controlled fire. At Koobi Fora and Chesowanja, both in Kenya, small patches of reddened soil were found in areas containing stone tools up to 1.5 million years old. To try to prove that Early Stone Age campfires caused the discoloration, researchers in the 1980s and ’90s used techniques such as magnetic susceptibility analysis and thermoluminescence dating. The first tool detects burned earth by gauging fluctuations in its magnetic field; the second determines how long ago an object was heated by measuring the photons it emits when baked in a lab. Although these methods showed that burning had occurred, the evidence is simply too sparse to convince most archaeologists that humans — not wildfires or lightning — were responsible./+\

“Another promising site is a South African cave called Swartkrans, where archaeologists in the ’80s found burned bones in a section dating between 1 million and 1.5 million years ago. In 2004, Williams College chemist Anne Skinner analyzed the bones using electron spin resonance, which estimates the temperature to which an artifact has been heated by measuring molecular fragments called free radicals. She determined that the bones had reached at least 900 degrees — too hot for most wildfires, but consistent with a campfire. But since the cave has a gaping mouth and a downward-sloping floor, naysayers argue that the objects might have washed in later after being burned outside./+\

“Until the Wonderwerk Cave find, Gesher Benot Ya’aqov, a lakeside site in Israel, was considered to have the oldest generally accepted evidence of human-controlled fire. There, a team of scientists found traces of numerous hearths dating to between 690,000 and 790,000 years ago. A wide range of clues made this site convincing, including isolated clusters of burned flint, as if toolmakers had been knapping hand axes by several firesides. The team also found fragments of burned fruit, grain and wood scattered about./+\

“Then came Wonderwerk. The ash-filled sediment that Goldberg and Berna found came from a spot approximately 100 feet from the entrance to the tunnel-like cave, too far to have been swept in by the elements. The team also found circular chips of fractured stone known as pot-lid flakes — telltale signs of fire — in the same area. These clues turned up throughout the million-year-old layer of sediment, indicating that fires had burned repeatedly at the site.”/+\

“Does that mean fire drove the evolution of H. erectus? Is the cooking hypothesis correct? The occupants who left these ashes at Wonderwerk lived nearly a million years after the emergence of H. erectus. Goldberg and Berna point out that it’s unclear whether the cave’s inhabitants knew how to start a fire from scratch or depended on flames harvested from grass fires outside the cave. If they were eating barbecue, it may have been only an occasional luxury. Whether that could have had an impact on human development remains an open question.” /+\

Humans Started Fires in Israel 790,000 Years Ago?

A study by Israel scientists suggests that hominins learned to start fires about 790,000 years ago and this may have played a role in the migration of ancient humans from Africa to Europe. Although no ancient matches or other kind of fire starter were found at the site, experts believe that burned flint patterns found in the same place proves a fire-making ability, Reuters reported. [Source: Ancient Foods, PressTV, October 27, 2008]

According to PressTV: “Studying the flints found at an archaeological site on the bank of the river Jordan, Hebrew University scientists in Jerusalem (al-Quds) found that ancient humans could start fire, rather than relying on natural phenomena such as lightning. “The new data shows there was a continued, controlled use of fire through many civilizations and that they were not dependent on natural fires,” archaeologist Nira Alperson-Afil said.

“Since the site is located in the Jordan valley, between Africa and Europe, experts believe the invention of fire has had a great role in the migration of humans northward. “Once they mastered fire to protect themselves from predators and provide warmth and light, they were secure enough to move into and populate unfamiliar territory,” said Alperson-Afil.

In June 2015, scientists announced that they had firm evidence that fire was being used on a regular basis at Quesem Cave in Israel more than 300,000 years ago as evidenced by large quantities of burnt bone, heated soil lumps, ash deposits, and most significantly, a 300,000-year-old hearth in the center of the cave. An analysis of the hearth revealed that it has been used repeatedly over time. [Source :Mark Miller, Ancient Origins, July 22, 2015]

Peking Man and Fire

Peking Man

For a long time, one of the oldest largely-accepted examples of fire used by an ancestor of modern humans is a group of burned animals bones found among remains of Homo erectus in the same caves in Zhoukoudian, China where Peking man was found. The burned bones have been dated to be about 500,000 years old. In Europe, there is evidence of fire that is 400,000 years old.

In 2015, Chinese scientists asserted that Peking Man set up fireplaces and cooked food about 600,000 years ago—the earliest evidence for fire use by a human species. They found fireplaces enclosed by a circle of rocks and burned rocks, soil and bones at the Zhoukoudian site. Gao Xing, with the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, said archaeologists spent three years excavating the site and found lime that he says resulted from limestone being burned."Source: Mark Miller, Ancient Origins, July 22, 2015 /*/]

The China Daily reported: “A fire site, sintering soil, and burned rocks and bones were uncovered at the site, said Gao Xing."Some of the animal bones were entirely carbonized, turned black both outside and inside," Gao said. "It is safe for us to conclude that this is the result of burning." Fire sites encircled by rocks and lime resulting from the burning of limestone were also found, Gao said. [Source: China Daily, July 19, 2015 |+|]

Ashes, burned bones and rocks, as well as charred seeds were also found at Zhoukoudian fame in 1929, Gao said, leading many archaeologists to agree that Peking Man knew how to use fire. But there has always been skepticism that they resulted from natural fire. "The evidence this time is more convincing," Gao said. "It has been found under the earth untouched, without weather damage. "This shows us that Peking Man could not only keep kindling, but knew how to control fire." |+|

Mark Miller wrote in Ancient Origins: “Although scientists estimate that ancient humans began using fire over a million years ago, it had been unclear when people starting using it on a regular basis, for example, for cooking daily meals. Discoveries earlier this year in Quesem Cave in Israel confirmed people were using fire 300,000 years ago, but the Zhoukoudian find provides even earlier evidence. /*/

Fire Not Widely Used Until 350,000 Years Ago — Why Then?

Zach Zorich, Archaeology magazine Humans first made controlled use of fire about a million years ago, but there isn’t much evidence that it was used widely at that early date. A team of researchers from the University of Arizona and the University of Haifa examined the evidence of fire use at 11 Paleolithic sites in the Levant and found that it was not common until around 350,000 years ago. [Source:Zach Zorich, Archaeology magazine, May-June 2015]

When and how fire came to be used by humans has become an area of renewed interest to paleoanthropologists. “There are all kinds of interesting evolutionary developments inherent in how fire is incorporated as an element of technology, and even of social life, that we haven’t really thought about because we were mainly concerned with the earliest use of fire,” says Steven Kuhn of the University of Arizona.

Beyond just providing warmth, fire kept predators away and led to cooked food and better nutrition, and it also may have been a focal point for social activities. According to Kuhn, there is evidence that the way living spaces were organized changes when people adopt fire. Why this change in fire use occurred is a matter of conjecture. It could be that earlier than 350,000 years ago people were controlling and using naturally occurring fires, says Kuhn, and that only later did they learn to start fires on their own.

Fire an Inspiration for Hominins

Some scientists say there is evidence suggesting that fire may have influenced the evolution of the human mind. Thomas Wynn wrote in Smithsonian Magazine: “It’s well-known that fire enabled the survival of early humans by providing warmth as well as a means to cook food and forge better weapons. Yet research into cognitive evolution—a field of study that brings together psychology, anthropology, neuroscience and genetics—suggests that fire’s most lasting impact was how our responses to it altered our brains, helping endow us with capabilities such as long-term memory and problem-solving. [Source: Thomas Wynn, Smithsonian Magazine, December 2012 /^]

“Archaeological evidence suggests that the controlled use of fire began with Homo erectus, who emerged nearly two million years ago. For those early hominins, a fire at night served as a light source and a way to deter predators. John Gowlett, a University of Liverpool archaeologist, argues that this innovation led to a profound change in how our brains regulate time. After the sun goes down, our ape cousins spend the entire evening asleep or inactive in nests. But the creation of artificial daylight enabled the hominin brain to adapt and evolve to the point where humans now remain alert and active for over 16 hours a day./^\

“Psychologist Frederick L. Coolidge of the University of Colorado further argues that fire altered the quality of sleep. During rapid eye movement (REM) sleep, the most vivid dreaming occurs and the brain consolidates long-term “procedural memories,” which allow us to retain skills and repeat previously learned tasks. The downside is that REM sleep is accompanied by a form of near paralysis known as muscle atonia—not the state you want to be in if you’re surrounded by animals that want to eat you. Using fire to keep predators away would have made it safe for early hominins to indulge in more REM (modern humans spend 25 percent of sleep in REM, compared with up to 15 percent for apes and monkeys), improving their ability to learn multistep tasks such as tool manufacturing. /^\

“Fire might also have improved our ability to think about many things at once and relate them to one another. This “working memory” is an essential trait for imagining and executing complicated plans. Psychologist Matt Rossano of Southeastern Louisiana University speculates that small social groups first achieved this altered mental state some 100,000 years ago around the campfire. Focusing on a specific object—in this case, fire—is a way to achieve a meditative state. The brain regions that activate to trigger meditation overlap extensively with the regions governing working memory. And, since meditation also has benefits for health, Rossano proposes that evolution would have favored those who were good meditators, allowing them to pass their ability along to their progeny. /^\

“By regulating attention, our ancestors were able to make contingency plans—in which alternative responses to problems were planned in advance. These attributes gave us a marked advantage in the face of competition from archaic humans such as Neanderthals; they also underpin our ability to cope with the huge variety of tasks required by modern life. The most enduring tool that fire ever made might just be the human mind. The next time you find yourself lost in thought while gazing at a fireplace ablaze or even a solitary candle flame, consider this: Being mesmerized by fire might have sparked the evolution of the human mind.” /^\

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