The Evolution of the Human Capacity for “Killing at a Distance”: The Human Fossil Evidence for the Evolution of Projectile Weaponry

Recent analyses of MSA and Middle Paleolithic points suggest that true long-range projectile weaponry — most likely in the form of spearthrower-delivered darts — evolved in Africa sometime between 90–70 ky BP, and was part of the tool kit of modern humans who expanded out of Africa after this time. This possibility has important implications for our understanding of behavior change during the MSA, the evolution of modern human predatory behavior and subsistence strategies, and the nature of the competitive interactions that occurred between modern humans and the archaic humans they encountered on their diaspora from Africa. Research into the origins of projectile weapons can be informed by analyses of the skeletal remains of the prehistoric humans who made and used them, since habitual behavior patterns — especially biomechanically stressful actions like forceful throwing — can be imprinted on the skeleton through both genetic and epigenetic pathways. Previous analyses of humeral diaphyseal geometry in Neandertals and early modern Europeans concluded that habitual, forceful throwing is reflected in the fossil record only after 20 ky BP, suggesting a relatively late origin of projectile weaponry. In contrast, recent work on humeral torsion angles in these same groups reveals some evidence to suggest that throwing-based projectile weaponry was commonly used by the earliest modern Europeans. Other aspects of the skeleton, such as scapular glenoid fossa and ulnar supinator crest morphology, might contain a signature of habitual throwing, but have not yet been examined. Here we analyze variation in scapular and ulnar morphology within and between groups of fossil and recent humans relative to the question of the origins of projectile weaponry. Although the results are not clear-cut, the overall pattern of osteological indicators is consistent with the claim that projectile weapons arose in the African later MSA and moved into Europe in the hands of modern humans.