3D Modeling of Bone Daggers from Papua New Guinea
· Managed by: Dana Carpenter
Bone daggers were once widespread in New Guinea. Their purpose was both symbolic and utilitarian, with the primary function of stabbing and killing men at close quarters. Most daggers were shaped from the tibiotarsus of cassowaries, but daggers shaped from human femora carried greater social prestige. The cross-sectional curvature of human bone daggers would suggest superior mechanical performance, but the material properties of cassowary bone are unknown. It is therefore uncertain whether the macrostructure of human-bone daggers exists to compensate for inferior material properties or to preserve the value of a prestigious object. To explore this question, we used computed tomography to examine the structural mechanics of 10 daggers accessioned in the Hood Museum of Art, Dartmouth College. We found that human and cassowary bone have similar material properties and that the cross-sectional geometry of human-bone daggers results in higher moments of inertia and a greater resistance to bending. The superior mechanical performance of human-bone daggers was supported with data from finite element models, which found greater resistance to larger loads with fewer failed elements. Taken together, our findings suggest that human bone daggers were engineered to preserve symbolic capital, an outcome that agrees well with the predictions of signalling theory. This MorphoSource project contains the 3D surface files (.stl format) used to perform the analysis.