How Strong were the Neandertals? Leverage and Muscularity at the Shoulder and Elbow in Mousterian Foragers Abstract Strength – the ability to exert relatively large forces on objects in the external world – was likely a critical component of Neandertal adaptation to Pleistocene Eurasia. Neandertal postcranial skeletons tend to be robust, reflecting a body that was well adapted to generating and withstanding large forces. A consideration of the size of muscle attachment sites and of mechanical advantage (or leverage) in the upper limb of Neandertals, early modern humans and recent human samples reveals pronounced upper body strength in the Neandertals relative to most modern humans. Upper body strength was probably important to hunting success in the context of close- range hunting with hand-delivered weapons, and greater strength probably increased the diversity of prey species the Neandertals could hunt. Long- range projectile weaponry, as possibly employed by early modern humans, would have relaxed to a great degree the need for upper body strength in hunting success. H ow strong were the Neandertals? It is axiomatic that Neandertals had robust skeletons, with bones and joint systems that were well-adapted to withstand relatively large forces (1–9). Since the mag- nitude of biomechanical loads, rather than their frequency, appears to be the most potent osteogenic stimulus (10–12), the robusticity of the Neandertal skeleton suggests that these archaic humans were regularly generating bending and other forces on their skeletons that were larger than those normally incurred by modern humans living in agricultural or industrial economies. Most forces operating on the skeleton, whether internal (e.g., tension generated by muscles, joint reaction forces) or ex- ternal (e.g., ground reaction forces, gravity acting on held objects), are proportional to the ability of muscles to produce tension (13): by infer- ence, the robust skeletons of Neandertals suggest that they had elevated levels of muscular strength relative to most modern humans. Strength – considered here as the ability to exert force on objects in the external world – was likely an important component of Neandertal adaptation. Among African bovids, Grand (14:375) noted that muscle mass was central to habitat choice, dietary specialization, social struc- ture, and male agnostic behavior, and was thus »part of the fabric of be- havioral ecology« in these antelopes. While muscle mass may no longer be part of the behavioral ecology of humans living in industrialized, STEVEN E. CHURCHILL 1 JILL A. RHODES 2 1 Department of Biological Anthropology and Anatomy Duke University Durham, North Carolina 27708 USA 2 Department of Biological Anthropology and Anatomy Duke University Durham, North Carolina 27708 USA Correspondence: Steven E. Churchill Department of Biological Anthropology and Anatomy Duke University Durham, North Carolina 27708 USA E-mail: churchy@duke.edu Key words: hominin paleontology, paleoanthropology, biomechanics, functional morphology. Received April 27, 2006. PERIODICUM BIOLOGORUM UDC 57:61 VOL. 108, No 4, 457–470, 2006 CODEN PDBIAD ISSN 0031-5362 Original scientific paper