Fig. 2. Mineral content as % dry mass (DM) in eight species of elasmobranch, including one axially undulating batoid, the electric ray. There are significant differences among species (F_7,159=15.061; P<0.001). We tested material properties of 20 vertebrae each from five gray smooth-hounds M. californicus (boxed). Letters above the box and whisker plot denote significant differences and species are color-coded by order. N=10, except for M. californicus (N=100).