Weddell seals, which are excellent divers, during lactation provide so much iron to their pups that the mothers then dramatically limit their own diving and underwater foraging capabilities.
Weddell seals, which are excellent divers, during lactation provide so much iron to their pups that the mothers then dramatically limit their own diving and underwater foraging capabilities.
This is according to a new paper, “Iron mobilization during lactation reduces oxygen stores in a diving mammal,” published in Nature Communications.
“Offload of large amounts of iron hinders female Weddell seals’ ability to maintain their own endogenous heme [hemoglobin and myoglobin] stores, and post-partum females have shorter dive durations following weaning than skip-breeders,” the paper states, referring to non-breeding seals that were used as a control group in the study. “High iron demand during lactation ultimately leaves dive capacity as a cost of reproduction in marine mammals.”
Seals have much greater iron loads than terrestrial mammals because the seals need those proteins to carry oxygen in their bodies, says Michelle Shero, lead author of the paper. “That basically acts as a sort of internal scuba tank for those animals that allows them to dive for so long,” says Shero, assistant scientist at Woods Hole Oceanographic Institution's Biology Department. “The females are essentially transferring their dive capacities to the pups when they nurse, through this transfer of iron. No one has looked at that before.”
Read more at: Woods Hole Oceanographic Institute
A female Weddell seal lays on the ice with her pup in Antarctica. A new WHOI-led study shows that during lactation, female Weddell seals provide so much iron to their pups that the mothers then need to dramatically limit their own diving and underwater foraging capabilities. (All images were taken under permit NMFS 17411-03) (Photo credit: Michelle Shero/ © Woods Hole Oceanographic Institution)
