10. About the dating of the first use of fire.

How dare I assume that this taming of fire occurred some 2 million years ago? Most paleos don’t go farther back than the 790,000 years old Gesher Benot Ya’aqov site in Israel, where charred wood and seeds were recovered[1]. Most paleos only accept evidence of fire use when there are hearth stones used; but even today San people don’t use hearth stones when the cook a tuber en route. They dig up a tuber, gather some dry material and branches, sit down, make fire with turning around the point of a digging stick between the hand palms onto a dry piece of wood. When the tinder glows, they blow it in flame et voila!: fire. Some brave paleos accept the evidence from Swartkrans and Chesowanja dating 1.5 million years ago, but that is the limit.

For me as a humanosopher, there are three kinds of evidence of an earlier use. First: there is no other way our ancestor-australopiths could have evolved smaller teeth and more gracile chewing apparatus (mouth) than through more soft and digestible food. Second: no other way to become larger beings and with larger brainpans, than through some kind of radically improved food supply. As experimentally proven by Richard Wrangham[2], a raw (not cooked, not grilled, not roasted) chimpanzee diet would be simply inadequate to sustain larger-brained beings of human size. Three: palaeontologists such as Ralph Rowlett and Randy Bellomo studied the differences in the soil beneath a natural fire and a campfire. The soil under campfires reaches much higher temperatures and a campfire leaves behind a bowl-shaped layer of highly oxidized and magnetized soil. At Koobi Fora in the African Rift Valley, Jack Harris of Rutgers University in New Jersey found such evidence of campfires dating 1.6 million years ago. Fire control must have started a long time before that moment.

‘2 million years ago’ is of course not an exact date; it is just an educated guess.

Perhaps controlled fire existed even earlier than these 2 million years ago. The first ‘professional’ stone tools found at Kada Gona are 2.6 million years old. They attest to a new niche for protein: meat.

For the start of meat consumption, we have to look back to about 6 million years ago: to the hides that could be found all over the Miocene savannah. In the following millions of years the hooligans of the savannah, ever more audacious with their stones, learned to chase away feeding predators from their prey. That was the moment when the males began to contribute to the diet: carrion became an increasingly important part of nutrition.

About 2,5 million years ago, the earth climate became even more cool and dry: the onset of the Ice Ages. Woodland savannah began to turn into desert savannah. The carrion competition grew more fierce. The best sources of carrion, the pachyderms (elephants, rhinos, hippos) had skins that were too thick for lions and hyenas and vultures to penetrate. Those predators had to wait until, after two or three days, the skin cracked open by decomposition gasses. However, with their knife-sharp stone tools the ancestor-australopiths could start processing the dead animal immediately!

The evidence of the stone tools of Kada Gona (2,6 million years ago) is recently transcended by the publication of the Dikika Research Project: evidence of stone tool use and meat-eating dating back 3,4 million years![3] And who made and handled this early stone tools? In June 2010, the discovery of Kadanuumuu, a 3.6 million years old australopith, was published. Its skeleton was found in Afar, where also the famous Lucy-skeleton was found. But Kadanuumuu was nearly a half million years older, much taller and had a more humanlike shoulder blade. So in my view, these people were the butchers of the Dikika antelope from 3,4 million years ago.

The image on the right is a artist reconstruction of the Dikika Child fossil

Meat was a new protein niche for our hooligan ancestors. It incited them to improve their stone ‘knives’. For millions of years, the standard way to make a ‘knife’ or scraper had been to smash a stone against another stone or rock, and then pick out the best ‘knife’. In the new circumstances, this was no longer sufficient. I think knapping the ‘knife’ from a core stone with a hammer stone was too risky for long, bent ape fingers (they still needed those ape fingers for climbing quickly into trees for sleeping and safety). But in order to improve the stone ‘knives’ they needed some knapping technique; and in order to develop a knapping technique they would need shorter, “handier” fingers.

Evolution had to find a balance between the need for long, bent fingers for climbing and making nests in trees on one side, and the need for shorter, handier fingers for knapping better knives on the other. It was the use of the fire that altered this balance. Since the fire provided protection from predators, this made it possible to stay on the ground instead of climbing in a treetop to build nests. Because our australopith ancestors no longer needed to climb trees at night, they no longer needed long “ape” fingers. This allowed the development of shorter, handier fingers suitable for better knife production.

[1] in a recent PNAS article (March 2011) the paleos Roebroeks and Villa suggest that the real control of fire is not older than 400.000 years; we have to take in consideration that their research only concerns European archaeological sites, and that they emphasize that earlier use of fire was possible in an opportunistic way: using smoldering wood from a natural fire, keeping it smoldering in a gourd or something
[2] Cooking Up Bigger Brains (2008); Wrangham himself did a research experiment by trying to live on a chimpanzee diet of fruit and raw meat: he found it not feasible for humans!
3] in a PNAS-article 17 Oct.’10 Dominguez-Rodrigo et al. charged this claim and proposed the marks as inflicted by animals trampling on the bones. However, they didn’t look at the original specimens but based their arguments on photos of the bones. Moreover, their research lacked the rigor of multiple person blind testing. The arguments were easily fielded. The paper was rushed forward in a scientifically unjustified hurry.

2 Responses to “10. About the dating of the first use of fire.”

  • Alan:

    The Humans as Scavengers Myth
    I would like to suggest a challenge to a minor comment towards the end of your piece: eating carrion.
    It has become a bit popular in Paleoanthropology to suggest that early homo hunter-gatherers were scavengers rather than proper hunters, largely on the premise that a dead animal is easier to catch. What, however, is the reality of the ecological economy on the Serengeti? Dead animals are easier to catch and the big players figured that out millions of years before homo showed up. Lions at the top of the list followed by hyenas and jackals. The smaller players in the meat market are such as leopards and cheetahs who kill and eat what they can before the scavengers run them off. Homo would most likely have entered this business with that same strategy. It is easier to catch and kill an antelope or zebra than to chase away a pride of lions from one already dead.
    Let’s look also at our guts. Chimp and man alike eat fresh food, spoiled food makes us sick and a good case of diarrhea to anyone living a calorie challenged life is likely fatal. Preserving food and keeping it edible is today a trillion dollar business. If any human ever evolved to eat spoiled food they would have a great advantage – they could eat what is now waste. We see no evidence of this digestion ever evolving. Humans as scavengers does not seem to fit the evidence.

    See also: http://popular-archaeology.com/issue/june-2012/article/the-hard-stuff-of-culture-oldowan-archaeology-at-kanjera-south-kenya

    Consider also: If early homo was a scavenger at the bottom of the meat chain, then moved up to top predator, some other critter would have moved into that niche. But I see no scavengers at the bottom save vultures, and among spoiled meat eaters, scavengers all appear near the top or eat worse than jackals. I suspect that was always the case.

    • admin:

      @ Alan,

      Thanks for your comment, and for the interesting link!

      Indeed, our guts are no longer equipped to eat carrion today. And chimp guts
      never were: chimps and bonobos can hunt in their forests. Our earliest
      ape-men ancestors needed to become bipedal, so much slower than quadrupeds.

      In my scenario, as meat eaters they started bottom of the ladder: scraping
      the rest tissue on the skins they found on the open savanna. Residues from
      sabretoothers or lions, from hyenas or jackals of the second shift, and from
      the vultures of the third shift. Natural selection favored guts that could
      digest carrion.

      After many generations a gang of men shouting and throwing stones dared
      chase away competitors from their prey: first the vultures, later the hyenas
      or jackals, and in the end even lions, at least for a moment, to cut of
      quickly a piece of meat.

      Even today hunters do this sometimes. Lions and other ‘big players’ have
      learned to avoid confrontation with humans. When Pygmies are not hunting but
      move through the forest, they laugh and sing an clap hands to make noise so
      that those animals can skedaddle in time.

      In the end, the stomachs that had been adapted to eating carrion may have
      evolved to the more sensitive stomachs that we humans have today; factors
      such as the introduction of fire (being able to cook things) may have
      contributed to this reverse adaptation.

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