The field research team has discovered a 29 year old Weddell seal mom with her 20th pup at the Hutton Cliffs Weddell seal pupping colony in Erebus Bay. "This is a special female," says Montana State University ecologist and Co-Principal Investigator Jay Rotella who is working with the field team out on the sea ice. "She was born in 1983 at North Base [of the Erebus Glacier Tongue] and has had all her pups at Hutton Cliffs."
At 29 years old with her 20th pup born this year, she is one of the oldest Weddell mothers in the project's extensive database, and one of the most productive Weddell mothers in the history of the Erebus Bay population study. The Weddell mom and pup are shown below in a photo by Jason Jones with the Weddell seal population study field research team.
Because of the project's long-term database of Weddell seals in the Erebus Bay study area, a database now covering 43 years, researchers are able to determine the pupping histories of most of these females. They know when and where the mother seals were born, what years they had pups, and where, and whether those pups survived to have pups of their own.
By accessing the project's extensive database, Jay Rotella reports that the 29 year old seal first returned to the Erebus Bay pupping colony at Hutton Cliffs at ages 5 and 6 without a pup in either of those early years. She then had her first pup at age 7, which is average for new Weddell moms.
What is so remarkable about this Weddell mom is that she has since had pups at ages 8, 9, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, and 29. Jay says, "That is pretty unusual in that she had 16 pups in a row and has had 20 pups overall!" Weddell seal moms usually have around 2 pups every 3 years. This seal skipped the most recent two years (ages 27 and 28) without having a pup, however she did show up at the South Base pupping colony both of those years.
Most Weddell seal females live to around 15 years of age if they can make it through their first difficult years after weaning and being left to fend for themselves. Only around 20% of Weddell female pups will survive long enough to have pups themselves; and they usually produce on average only a handful of pups each in their lifetimes.
Weddell seal females born in Erebus Bay tend to return to Erebus Bay to have their pups, showing strong birth-site fidelity. This 29 year old Weddell mom has given birth to all of her pups at Hutton Cliffs, which is a relatively short distance from her birth place at the North Base of the Erebus Glacier Tongue.