Weddell seal iron dynamics and oxygen stores across lactation

The profound impacts that maternal provisioning of finite energy resources has on offspring survival have been extensively studied across mammals. However, in addition to calories, we tested whether high hemoprotein concentrations in diving mammals necessitates exceptional female-to-pup iron transfer. To answer this question adult female Weddell seals (Leptonychotes weddellii) were handled across the austral summer. This included post-partum females during lactation and post-weaning. To demonstrate that any observed changes in iron dynamics were due to lactation, equivalent skip-breeding females (i.e., that did not produce a pup) were also handled. We measured numerous indices of iron mobilization (ferritin, serum iron, total-iron-binding-capacity, transferrin saturation, milk iron concentration), hemoprotein concentrations, and oxygen stores.