My approach to the analysis of structural design of bat wings investigates a number of critical components of the whole wing, and synthesizes the results into an integrated picture. First, I have, after solving a number of unique technical problems, used in vivo strain analysis to obtain the first direct and detailed information concerning bone loading during flight, using the gray-headed flying foxes of eastern Australia (Pteropus poliocephalus) as an exemplar species. I have shown that the loading of the skeleton varies tremendously among wing bones, and that, in particular, the loading of the proximal portion of the wing, the humerus and radius, is dominated by unusually large torsional and shearing forces (Swartz, Bennett and Carrier, 1992). In contrast, the distal elements, the metacarpals and phalanges, experience almost pure bending loads that increase proximodistally to the largest values yet measured within vertebrates at the distal extremity of the proximal phalanx (Swartz, 1996a).
