Smithsonian National Zoological Park l Friends of the National Zoo



NSF Polar Program

U.S. Antarctic Program

The National Zoo's Antarctica Expedition is sponsored by the National Science Foundation's Office of Polar Programs.

All photographs depicting Weddell seals were taken under NMFS Permit No. 763-1485-00 issued under the authority of the Marine Mammal Protection Act.




$62.53 million raised; 78.2% of $80 million goal

Weddell Seal Project

The Weddell seal, most southern of all mammals except humans, is an example of a fascinating phenomenon. They feed very little if at all while nursing their young, and break down the fat and protein of their own bodies to support lactation. By a miracle of seal alchemy, the mother’s flesh is turned into milk that nourishes the young. The milk is so rich that Weddell seal pups quadruple their birth weights in only six weeks.

During this time, the once portly mother seal shrinks to almost half her initial mass. Great heaving rolls of flesh when they first come out on the ice, Weddell seal mothers look thin and worn only five weeks later, while their pups lounge on the ice in their silvery new coats.

The Weddell seals that come to the colony to give birth are not all the same. Some are small or lean, and do not seem to have the fat they need to feed their pup for the long six weeks ahead. We believe that mothers too thin to fast have to go out under the ice to hunt for food that will give them the energy and nourishment to make milk for their pups.

Some of the questions we would like to answer are:

  • Do all seals hunt, or only those that have to?
  • What happens if there is no food, or if hunting for what prey can be found takes more effort than it is worth?
  • Do young seals learn to hunt while they are still with their mothers, or only from necessity once they are abandoned and starving?

Read more about the project