How much energy does it take to raise a Weddell seal pup?

I'm delighted to back such a worthy project! Mary Lynn

Jason, Thanks for the questions! Our project has quite a bit of data on pup mass at birth and weaning. What we've found is that pups of young and old mothers are born at a lower mass than pups of prime age females. When we weigh pups at weaning though we find that pups of young mothers are still relatively lighter than other pups but pups of old and prime age females are nearly the same weight. This would imply that older mothers are investing more energy into weaning a heavy pup. If older females are in fact investing more energy into their pups we would expect to find a greater proportional mass loss in older females than the other two age classes. The study of southern elephant seals compared the mass loss during lactation and mass gain during post-weaning foraging of females across different islands. The study found that southern elephant seals at certain islands on average have much lower absolute masses but lose and gain a proportionally similar amount of mass throughout the year. You can read the full paper at this link: http://journals.cambridge.org/action/displayFulltext?type=1&fid=9080713&jid=ANS&volumeId=25&issueId=06&aid=9080710&bodyId=&membershipNumber=&societyETOCSession=

Good luck! Great project.

"Using mass measurements derived from photographs we can assess how Weddell seal mothers energetic investment changes with age. " I'm curious what you *expect* to find. Something similar to those southern elephant seals on which this technique has been used before, or something different? And what were those results on those elephant seals?