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Archaeologists Assess Killing Power of Stone Age Weapons

The views expressed are those of the author and are not necessarily those of Scientific American.

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Experimental spears

Stone-tipped spears and plain wooden spears were launched into ballistics gelatin. Image: Jayne Wilkins et al. in An Experimental Investigation of the Functional Hypothesis and Evolutionary Advantage of Stone-Tipped Spears. PLoS ONE 9(8): e104514. doi:10.1371/journal.pone.0104514 (2014)

Half a million years ago in South Africa early human ancestors shaped lumps of rock into lethal points and then attached them to wooden shafts, producing the earliest known stone-tipped spears. It took a lot more time and effort to make these multicomponent implements than to make a simple, untipped wooden spear, but the result was a deadlier means of dispatching prey. That’s what many archaeologists have assumed anyway. Few have put that claim to the test, however.

To that end, Jayne Wilkins of Arizona State University and her colleagues recently conducted a controlled experiment aimed at gauging the efficacy of wooden spears and stone-tipped spears. They focused on hand-delivered spear technology, as opposed to high-velocity projectile technology such as arrows, which were invented much later.  Using a calibrated crossbow to simulate spear thrusting, the investigators plunged replicas of the two types of weapons into ballistics gelatin, a substance that is similar in density to the muscle tissue of humans and other animals and that is typically used to show how modern ballistic weapons damage flesh. They then measured the penetration depth and the size and shape of the gelatin “wounds.”

The team found that both types of spears penetrated to about the same depth. The stone-tipped spears delivered significantly larger internal wounds, however, creating cavities that were nearly 25 percent larger than those left by the untipped spears.

“A larger wound track translates to more tissue damage, an increased probability of hitting the heart, lungs, and/or major blood vessels, and an increased probability of incapacitating prey,” the researchers explain in a paper published on August 27 in PLOS ONE. That boost in destructiveness would have provided a safer, more reliable way of bringing home the bacon. And enhanced access to meat, the authors say, would have had far reaching effects on our ancient ancestors:

“Regular use of this new technology could have reduced adult mortality, increased average lifespan, increased daily return rates of large, high-quality food packages, and decreased daily nutritional variance. These effects may have changed the amount and regularity of resources adults can contribute to dependents, with important implications for human life history. An increased juvenile period, higher female fertility, and pair-bonded cooperative breeding all may be explained in part by higher rates and reduced variability in successful resource capture among hunter-gatherers.”

Moreover, the technology could have changed the way early humans interacted, both with members of their own social groups as well as members of other groups:

“Computer simulations suggest that weapon use may be linked to human cooperation. Agents with extra-somatic weapons are more likely to cooperate with each other than agents without extra-somatic weapons, in part because of the increased risk of lethality when agents choose to defect.”

Amazing, isn’t it, how such a seemingly simple invention may have transformed humankind.



How Hunting Made Us Human

Scientific American Single-Topic Issue on Human Evolution (2014)





Kate Wong About the Author: Kate Wong is an editor and writer at Scientific American covering paleontology, archaeology and life sciences. Follow on Twitter @katewong.

The views expressed are those of the author and are not necessarily those of Scientific American.

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  1. 1. studyalot 3:00 pm 08/28/2014

    There are many hunters, especially archers, who can tell you a lot about killing animals with a sharp projectile. I don’t think that poking a stick with or without a stone point into gelatin tells you much

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  2. 2. Alitari 9:16 pm 08/28/2014

    Didn’t they do this a while ago on Mythbusters? They were testing time of production and lethality, but on arrows rather than spears. Napping a rock took a long time compared to the number of sharpened sticks you could make, but they came to a similar conclusion; the sharpened stick arrows could be used early in the hunt to weaken the prey, then stone tipped arrows would be used to finish them off.

    They also suggested that it might have been a matter of prestige; if you hunt with stone tipped arrows you’re using something that requires a lot of time and energy to make compared to someone hunting with just sharpened stick arrows.

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  3. 3. BuckSkinMan 10:02 pm 09/3/2014

    There’s basic confusion on the part of the researchers and Ms. Wong. The efficacy of sharpened stone projectiles is judged in therms of how much blood loss is created. It’s not about penetration depth or wound cavity size per se. Increasing wound cavity size does increase blood loss but even a deer shot with a modern arrow (much more efficient) will run for a distance before collapsing. An angry Aurochs or other mega fauna prey would likely remain violently reactive for a comparatively long time.

    Far more likely for paleolithic hunters would be for them to “gang stab” their prey. THIS is what required cooperation and coordination NOT from the (highly hypothetical) “safety committee” decision to cooperate in order to make it safer for fellow hunters.

    Really, I’m all for Science and scientific researchers but a phone call to any hunters they might know would clue them in a lot better than their own inexperienced, uninformed conjectures.

    Oh, and if they really wanted to simulate spear thrusts – they should have used live humans thrusting with normal human ability into ballistic gel.

    This article and the research it’s based on is farcical. A complete and kinda funny failure.

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  4. 4. nfcapitalist 4:33 pm 09/4/2014

    … the advantage might be to leave the spear point inside the animal, might even have used aconite or gone for the obvious, dried snake venom. Seem to remember there were grubs used by the !Kung San that would bring down large prey after being tracked for miles.

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