Data from: New Guinea bone daggers were engineered to preserve social prestige

Bone daggers were once widespread in New Guinea. Their purpose was both
symbolic and utilitarian; they functioned as objects of artistic
expression with the primary function of stabbing and killing people at
close quarters. Most daggers were shaped from the tibiotarsus of
cassowaries, but daggers shaped from the femora of respected men carried
greater social prestige. The greater cross-sectional curvature of human
bone daggers indicates superior strength, 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 of human femora or to preserve the symbolic value of a
prestigious object. To explore this question, we used computed tomography
to examine the structural mechanics of 11 bone daggers, 10 of which are
museum-accessioned objects of art. We found that human and cassowary bone
have similar material properties and that the geometry of human bone
daggers results in higher moments of inertia and a greater resistance to
bending. Data from finite element models corroborated the superior
mechanical performance of human bone daggers, revealing 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.