Projectile weapons and carnivores

Dr. Steven Churchill. Photo (c) Duke University/Les Todd

Last Tuesday, Duke University paleontologist Steven Churchill gave a talk at Sigma Xi in Research Triangle Park about how projectile weapons literally changed the trajectory of human evolution — and caused the extinction of Europe’s large carnivore guild. (It’s been a busy week, so I’m only now settling down to write this!) Churchill views projectile weapons of all kinds as “potent tools of persuasion” that can be used for both social control and social disruption. In his view, modern weapons like guns are more than objects that a person wields, they are social tools that can be used either to bully others or to control and persuade people. If you accept his assertion, try carrying this idea with you back in time — way back to Pleistocene Europe between 60 and 15 thousand years ago.

The Pleistocene epoch, which spans from roughly 1.8 million to 10 thousand years ago, is known for its really large land animals. Really large. We’re talking rats the size of modern rabbits, and lions nearly a half-meter longer than today’s. One thousand pound cave bears, wooly mammoths, wooly rhinoceroses and sabre-toothed cats all shared the same landscape with Neanderthals and early modern humans.

And it is the interface of Neanderthals with modern humans coming out of Africa that really interests Churchill. He said the two species would likely have had contact 60 thousand years ago, and by 40 thousand years ago they were sharing the same European landscapes. But by about 25 thousand years ago, there were no more Neanderthals. And by 12 to 15 thousand years ago, all of Europe’s megafauna had died off.

Many researchers have asked, “What happened to the Neanderthals?” In Churchill’s view, modern humans out-competed them in large part because their skeleton’s were better suited to throwing projectile weapons. Why does being able to throw a spear or use an atlatl matter? Imagine that you have a spear in your hand; it has a wooden staff with a squat stone tip hefted tightly to the top. Using a weapon like this, you must ambush your prey to kill it, or attack it when it is at a disadvantage — like in a muddy swamp. If you were to chuck the spear at your prey, you’d likely be able to hit a target within five and a half meters. (Keep in mind it is pretty darn hard to sneak within five meters of a wild prey animal.)  But if you have a throwing spear that you can launch from an atlatl, your range increases to about 39.5 meters, which allows you to access dangerous and easily-spooked food sources, like a wooly mammoth, from a much greater distance.

In Churchill’s view, there was steep competition for meat in Pleistocene Europe. Isotope analyses show that a Neanderthal’s diet was primarily meat based. And out on the landscape, a complex guild of top predators fought fiercely for prey too: lions, saber tooth cats, hyenas and wolves all had to make a living. Churchill said he interprets various evidence to indicate that Neanderthals were likely “not the top carnivore.” He asserts that human use of projectile weapons, in this case spear throwing, allowed them to dominate preferred habit – essentially excluding Neanderthals and keeping carnivores at bay that may otherwise harm them (humans) or steal their meals.

Fleshing out his theory, he explained several anatomical features present in humans but missing in Neanderthals that enable being able to throw objects with a lot of force. For example, he said that Neanderthal upper arm bones were not as well conditioned to twisting, and their shoulder joints were not as well adapted to torsion as were modern humans. And humans had larger ulnar supinator crests — common in people who throw heavy objects habitually — whereas Neanderthals lacked crests. (Visit here for his published comparative study.) {1}

“Neanderthal’s were not invested in throwing techniques,” he said. Churchill took the sum of evidence and funneled it toward one conclusion. “Humans were likely the behaviorally dominant carnivore, and they probably used social systems to deal with the carnivores and exclude Neanderthals in a competition for resources,” he said. All the large-bodied carnivores in Pleistocene Europe, and the Neanderthals, died off by about 25 to 15 thousand years ago, he noted.

So, does he think that humans also used spear throwing to make war against Neanderthals? On this point, he crafted his words carefully, citing evidence of a fossil Neanderthal skull that he believes provides evidence that something killed its owner with a projectile weapon. Having ruled out that Neanderthals likely used spear-throwing technology (he believes that early humans likely developed this in Africa, and carried it out in their diaspora), he places his chips squarely on an interspecies homicide, claiming that modern man lobbed the deathly blow from afar in this single 75 to 50 thousand-year-old case. But, he quickly pointed out that there was probably a mix of both interspecies aggression and intermingling between modern man and his Neanderthal cousins.

The one thing Churchill did not talk about was the role of climate in the Pleistocene carnivore extinctions. When asked, he said that isotopic data did not suggest a strong correlation between specific climate change events and extinctions. Yet many other studies do indicate links. I am certainly not an expert in this field, and I think that Churchill’s assertions about the use of projectile weapons as both a hunting and social control tool were incredibly thought-provoking, but I could not entirely swallow his assertion that spear throwing was the causative thing that did in the large carnivores. For one thing, the Late Pleistocene mega-faunal extinctions occurred on several continents, including North and South America and Australia. To accept his theory, I think you’d have to also accept that spear-throwing did in the megafauna on these continents too. And you’d have to dismiss the idea that climate or even disease could have been players. {2}

I tend to gravitate more toward blended ideas that take into account synergistic effects or the possibility of multiple causalities… and this is where I’m landing on this one. Overall, it was a very thought-provoking presentation, but I couldn’t quite take that last step with him.

NOTES:
{1} Rhodes JA Churchill SE. Throwing in the Middle and Upper Paleolithic: inferences from an analysis of humeral retroversion. Journal of human evolution. 2009 Jan;56(1):1-10.

{2} As always, please leave a comment if you have additional information or want to discuss. Especially if you are a researcher or have specialized knowledge in this area.