Why Fire Makes Us Human

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Wherever humans have gone in the world, they have carried with them two things, language and fire. As they traveled through tropical forests they hoarded the precious embers of old fires and sheltered them from downpours. When they settled the barren Arctic, they took with them the memory of fire, and recreated it in stoneware vessels filled with animal fat. Darwin himself considered these the two most significant achievements of humanity. It is, of course, impossible to imagine a human society that does not have language, but—given the right climate and an adequacy of raw wild food—could there be a primpoitive tribe that survives without cooking? In fact, no such people have ever been found. Nor will they be, according to a provocative theory by Harvard biologist Richard Wrangham, who believes that fire is needed to fuel the organ that makes possible all the other products of culture, language included: the human brain.


Every animal on earth is constrained by its energy budget; the calories obtained from food will stretch only so far. And for most human beings, most of the time, these calories are burned not at the gym, but invisibly, in powering the heart, the digestive system and especially the brain, in the silent work of moving molecules around within and among its 100 billion cells. A human body at rest devotes roughly one-fifth of its energy to the brain, regardless of whether it is thinking anything useful, or even thinking at all. Thus, the unprecedented increase in brain size that hominids embarked on around 1.8 million years ago had to be paid for with added calories either taken in or diverted from some other function in the body. Many anthropologists think the key breakthrough was adding meat to the diet. But Wrangham and his Harvard colleague Rachel Carmody think that’s only a part of what was going on in evolution at the time. What matters, they say, is not just how many calories you can put into your mouth, but what happens to the food once it gets there. How much useful energy does it provide, after subtracting the calories spent in chewing, swallowing and digesting? The real breakthrough, they argue, was cooking.

Wrangham, who is in his mid-60s, with an unlined face and a modest demeanor, has a fine pedigree as a primatologist, having studied chimpanzees with Jane Goodall at Gombe Stream National Park. In pursuing his research on primate nutrition he has sampled what wild monkeys and chimpanzees eat, and he finds it, by and large, repellent. The fruit of the Warburgia tree has a “hot taste” that “renders even a single fruit impossibly unpleasant for humans to ingest,” he writes from bitter experience. “But chimpanzees can eat a pile of these fruits and look eagerly for more.” Although he avoids red meat ordinarily, he ate raw goat to prove a theory that chimps combine meat with tree leaves in their mouths to facilitate chewing and swallowing. The leaves, he found, provide traction for the teeth on the slippery, rubbery surface of raw muscle.

Written By: Jerry Adler
continue to source article at smithsonianmag.com

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  1. The use of fire to cook food is definetely a way to increase intelligence eventually, but the fact that humans lost their body hair/ fur to become naked was surely the driving force behind seeking fire in the first place….cooking came as a secondary consequence, bare skin makes human beings highly sensitive and responsive to the temperature and humidity. We are a sensory animal with advanced conciousness and the ability to manipulate the environment to our needs. The lack of body fur /hair and our naked sensory skin drove many functions of humanity – surely that is more likely to be the link between primitive humans becoming early modern sapiens – by taking natural embers and keeping them lit and then eventually learning to make fire themselves to keep warm and to use as a weapon against predators, the cooking of food came later and only added to intelligence. Maybe the use of fire occured around the same time as humans lost their body hair, because the intelligence was already in humans before the first meat was thrown on the fire.

    • In reply to #1 by Light Wave:

      The use of fire to cook food is definetely a way to increase intelligence eventually, but the fact that humans lost their body hair/ fur to become naked was surely the driving force behind seeking fire in the first place….cooking came as a secondary consequence, bare skin makes human beings highly…

      Isn’t it possible that they invented fire first and then lost their body hair because it was no longer needed?

    • In reply to #1 by Light Wave:

      … but the fact that humans lost their body hair/ fur to become naked was surely the driving force behind seeking fire in the first place..

      That does not sound right, Why not just evolve more hair? fairly easy considering their ancestors were hairy.

  2. In reply to #1 by Light Wave:

    The use of fire to cook food is definetely a way to increase intelligence eventually, but the fact that humans lost their body hair/ fur to become naked was surely the driving force behind seeking fire in the first place….cooking came as a secondary consequence, bare skin makes human beings highly…

    That doesn’t sound likely at all, and is based entirely on imagination. We see monkeys eating cooked food ( burned by humans or natural forest fires) as a way to aid in digestion and allow for diversification of diet. Monkeys that eat charcoal bits are able to eat plants that otherwise cause them discomfort. Carbonization is at the root of our omnivorous ability. The carbon boost increases the economic viability of growing a bigger brain, allowing for the consciousness to control fire.

    Since speaking from imagination is very common in speculating on our origins, I propose the constant natural forest fires that have sculpted the design of many species also forged us. Perhaps drawn to the charcoal or predator-free perimeter surrounding a forest fire, our ancestors thrived. I imagine we were kicking cinders with bare feet for aeons, long before anyone harvested or domesticated fire. We were pyronated. Perhaps warmth allowed for sexual-selection to promote the hairless trend. The main problem I have with seeking fire as a result of hairlessness is there are plenty of hairless animals, and they are not known for seeking fire. The big chicken and egg paradox here is cephalization and carbonated food. Which came first? That’s what my totally made up story resolves for. If fire is our environment, it is a portable one. Firestick hunting changed the environment wherever humans spread and provided great surpluses of highly edible food, including meat.

    I like how the article focuses on the raw food fad. I appreciate anything that gives me more lisence to say, ‘STFU hippie’.

  3. Humans didn’t invent fire they witnessed it around and knew what it could do, it took quite a jump from using what was around, to making fire themselves to cook food….. I just wondered how close the link between hairlessness and fire use was in humans ? No doubt cooked food made bigger brains either way………. In response to Red Dog you said some animals eat cooked food ? what ? when does that happen…the animals don’t cook it for themselves ?… Questions are not an ‘imaginary opinion’, just a view, I’m not a scientist and dont claim to be one…..everyone is entitled to their view about origins on this site… but some things don’t leave much archaeological evidence and so speculation is not a threat and its not a wildly crazy idea either.

    • In reply to #4 by Light Wave:

      Humans didn’t invent fire they witnessed it around and knew what it could do, it took quite a jump from using what was around, to making fire themselves to cook food….. I just wondered how close the link between hairlessness and fire use was in humans ? No doubt cooked food made bigger brains eith…

      Scientists speak from imagination too, and sometimes absurdities are taken very seriously (serious enough to electroshock someones genitals, which is pretty serious). Take for instance the stories that were once told about the etiology of homosexuality, and how this resulted in conversion therapies that still persist to this day (currently outside the AMA’s purview). A lot of things make sense, to which there is absolutely no truth. It is a common epistemic error to think prosaic explanations are at all more viable.

      The most common hairlessness explanation I hear is sexual selection on the Serengeti; starting to walk upright, less hair exhibited genetic virtue of skin and muscle. Basically, it’s just sexy. I love the Aquatic Ape theory, that we lost our hair not from fire but from water, but this is not science, just a beautiful story.

    • In reply to #4 by Light Wave:

      I just wondered how close the link between hairlessness and fire use was in humans ?

      I don’t think hairlessness and cooking are related because:

      1. You don’t sit by the fire non-stop.
      2. the fire only warms one side of you at a time.
      3. women did cooking, not men.
      4. men have beards but not women.
      5. would body hair protect or hurt when a spark lands?

      Why are we hairless? I speculate:

      1. makes it tougher for lice.
      2. easier to swim
      3. more efficient cooling for long distance running/pursuit of prey
      4. we had invented clothes. We could custom tune the amount of cover needed.
      • In reply to #13 by Roedy:

        Why are we hairless? I speculate:

        From my reading, your idea #3 has the most interest at this point.

        more efficient cooling for long distance running/pursuit of prey

        I’m not convinced that sexual selection has any usefulness as an explanation (mentioned by others above) for hair loss. If production of body hair is directly related to testosterone production, then wouldn’t more male body hair = evidence of high testosterone = fertility + aggressive behavior (good for defense) and therefore be selected for rather than against?

        That’s why I think that on balance, there must be a very strong reason for males to lose body hair over time. Long distance running to wear out prey animals and the ability to sweat profusely seems the best reason I’ve heard so far. It’s purely anecdotal and therefore not worth anything, but are human females so repulsed by male body hair that we could actually have influenced it’s quantity over eons? I have doubts about that. I realize that our currently reproducing generation apparently favors a bare minimum or total lack of body hair in mates but aside from the 20-somethings out there on the scene now, I’ve never heard of much objection to male body hair in the past from other women unless the guy is covered with a thick pelt all over and in fact women I know agree that a certain amount (subjective) of male body hair is sexually attractive.

        In my late twenties I was at the beach with a crowd and one of the men of the same age, for some reason, had absolutely no body hair and this confused and repulsed me as I thought he looked like a large sexually immature child who still behaved like an adult male would. Yuck factor in full effect. Like I said above, anecdotal and speculation. I’ve never seen any surveys on the subject of women and their opinions of male body hair but if they’re out there I’d like to know about them.

  4. In reply to #3 by This Is Not A Meme:

    I like how the article focuses on the raw food fad. I appreciate anything that gives me more lisence to say, ‘STFU hippie’.

    haha. Dear Meme, not sure where you’re from but if you have the chance to take a stroll in an American Wal Mart you may change your mind about the raw foodists. I don’t think I have the ability to stick to a raw food diet but I give them credit for taking action against the creeping accumulation of adipose tissue that is readily apparent in this place. It’s totally out of control, take my word on that one.

    Have you heard of the Paleo-diet?

    http://en.wikipedia.org/wiki/Paleolithic_diet

    I’m pretty sure I can’t stick to Paleo-diet either. :-( There are advertisements in the Boston area for roommates to move in and live in a “Paleo-house”. I’m very interested to know what goes on in these houses. Is it just a Paleo-diet or are they attempting to reproduce Paleo social arrangements as well? I’d sure like to be a fly on the wall in one of these situations. :-D har! har! Maybe Richard Wrangham should look into it and write a book. He’s speaking at Harvard this coming week, by the way.

    • In reply to #5 by LaurieB:

      In reply to #3 by This Is Not A Meme:

      I like how the article focuses on the raw food fad. I appreciate anything that gives me more lisence to say, ‘STFU hippie’.

      haha. Dear Meme, not sure where you’re from but if you have the chance to take a stroll in an American Wal Mart you may change your mind…

      I’m pretty familiar with the different philosophical diets. Grew up in the midwest, never eaten meat. That basically requires a crash course in organic chemistry, or a critical foray through nutritional ‘sciences’. I respect the beliefs and even have a few somewhat outrageous ideas of my own; one of which involves the virtues of eating burnt food, and I’ve got a compelling argument for it, but I’m just making stuff up.

      For me the fatal flaw in these philosophical diets is the notion of an ideal, and that we can actualize to that ideal. There is no ideal in reality, hence the etymology of the word. Food is basically poisonous and kills us very slowly. It’s addictive. With a plentiful supply of vitamin C, our ancestors lost (for economic reasons) the enzymes to synthesize it on their own. Now we must eat citrus or die. It’s an ugly, tragic, highly functional paradox of nature, the kind that distressed Darwin.

      In this strange and apparently cruel operation one circumstance is truly remarkable. The larva of the Ichneumon, though every day, perhaps for months, it gnaws the inside of the caterpillar, and though at last it has devoured almost every part of it except the skin and intestines, carefully all this time it avoids injuring the vital organs, as if aware that its own existence depends on that of the insect upon which it preys!
      -Kirby

      I own that I cannot see as plainly as others do, and as I should wish to do, evidence of design and beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars, or the cat should play with mice.
      -Darwin

      These stories about what diet is best and why are just stories, attempts to make sense of something that is fundamentally senseless. Our metabolism is the story of our evolution, and its chaotic intricacy, people’s preexisting assumptions express through it like the Forer Effect or a Rorschach test. Raw Foodism and Paleo are Luddite diets, and this sentiment is present in the wikipedia article you linked. Then there are transhumanist CRON diets, which googling now I see are recently challenged. Diets based on ancestral cline, color, elemental spirit, etc. It’s all just stories, and if you’ll excuse me I must research if the Aquatic Ape Theory has a diet book, because if not my next post will be from my new beach-house on the central coast of Vietnam.

  5. I imagine there’s much more that the use of fire facilitated, beyond cooking and warmth and protection. Assuming language had already begun to evolve, the opportunity to sit around the fire late into the night and talk probably accelerated the development of higher concepts than the mundane survival skills. The ability to start a fire probably defined the first shamans, the phenomenon being regarded as magic.

    I speculate that this led to awareness of the potential for hominid ‘agency’ over the environment, as well as the obvious banishment of the predators in the dark, real or imagined.

  6. Our body size has something to do with it. A fire has to bring advantages which outweigh the expended effort in collecting and hording combustible material, and a fire to be of much use has to be of a certain size. If it is too small it is easily extinguished by wind or a slight shower and it gives little warmth and not enough heat to cook or heat water with. If it is too big it consumes more fuel than can be provided by a primate with two hands. A sustainable and useful fire which wouldn’t rapidly consume all available material is almost conveniently the right size for our purposes and our capacity to keep it going.

    Sshhh don’t tell creationists they’d cite it as evidence of a design feature.

  7. The use of fire and cooking to increase the energy efficiency of digestion is an elegant idea that delivers a few testable hypotheses. Innate wild food energy density in a geographic area might reasonably be matched with a corresponding population density. Now we must add a further requirement of innate fuel availability and also a fire preserving habitat (caves are good!)

    Fire use should correlate with height if nutrition is improved. Rate of heat loss should reduce with increased bulk/height as surface area increases less rapidly than mass, creating the added advantage of thermal efficiency for the well nourished body. Added direct (heat) and indirect (high calorie cooking) energy to a more energy efficient, larger body is a triple whammy and really does become a potent driver for hairless-ness.

  8. Dear comment No 11, Hot sun, hairless Serengeti dwellers. Seems a bit chicken or egg to me. I know lots of animals get winter coats but they don’t become naked in summer. Also the male of our species can be very hairy. Have you ever seen a chimpanzee with a handlebar moustache or a waistlength beard? Just a thought.

  9. OLD TOY BOY – are you serious, hairlessness is genetic, humans can’t conrol it or how they evolve
    RED DOG – sorry I mis quoted you as saying something about animals eating cooked food – It was in fact This is not a meme.
    THIS IS NOT A MEME – Not sure I follow what you are saying, Other animals are naked but dont seek fire…erm yes but only humans CAN seek fire and maybe because they were naked !! Humans have evolved eating a lot of cooked food other animals have not
    ROEDY – you miss quoted me..saying Hairlessness and cooking are not related… I didn’t say that….I said Hairlessness and FIRE USE are related…if your bare skin is cold, you may want to make fire and raw food is still available if you are hungry.
    Anyway fellow commentors My bad for hijacking this thread with hairlessness as opposed to the article of “Did Cooked food make us human” ? I’d say Highly likely – although master manipulation of our environment helped too.

  10. Lots of interesting ideas here but one or two commenters need to revisit natural selection. Attributes are not gained for potential use. In reply to No 13, lice are still doing very well and long distance running in pursuit of prey does not seem to me a very viable strategy. Lots of sweating means dehydration and the savanna is a dry habitat. They would have needed to carry water. Also fire would not have been needed for warmth in tropical areas. It is also notable that hunter gatherers have lived into modern times in fairly cold areas; southern Patagonia and southern Australia for example, and stayed more or less naked. The whole business of clothes is an intriguing subject.

  11. I have been wondering if the popularity of barbecuing food is somehow connected to the ancient practice of humans using fire to cook food, going back one to two million years. Is there a genetic component, i.e., an evolved human proclivity to use fire to cook food?

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