“…the force per unit area, or stress, σ, that builds in a material under load in response to deformation, or strain, ε) can therefore provide an understanding of the overall structure's mechanical capabilities and limits, with stress distributions and yield behavior pointing to performance boundaries, all of which can offer clues to loading regimes likely to be experienced in vivo. Because EI accounts for both material and structural properties, it is a useful metric for characterizing mechanical function in comparative studies, particularly when linking organismal function with evolutionary and ecological pressures (Koehl, 1976(Koehl, , 1977Macleod, 1980;Etnier, 2003). Flexural stiffness has been shown to correlate with loading regime and direction for a range of biological body support systems, from the limb skeletons of batoids and dogs, to the jaws of whales and pelicans, to the exoskeletons of crabs (Kemp et al, 2005;Taylor et al, 2007;Field et al, 2011;Macesic and Summers, 2012); these taxonomic comparisons also illustrate that higher levels of bending resistance can be attained evolutionarily by increases in either E or I, or in both.…”