Fig. 5.

Mass-specific molar equivalents of heme calculated from (A) blood (hemoglobin) and (B) muscle (myoglobin) oxygen stores in northern elephant seals and humans. Molar heme equivalents were calculated using a hemoglobin molecular weight of 65,000 g mol⁻¹ and myoglobin molecular weight of 17,000 g mol⁻¹. Data for species-specific blood volumes, muscle mass, hemoglobin and myoglobin concentrations are from previous studies (Kendrew et al., 1958; Hill et al., 1962; Åkeson et al., 1968; Oscai et al., 1968; Simpson et al., 1970; Bryden, 1972; Möller and Sylven, 1981; Hassrick et al., 2010; Ponganis et al., 2011).