Recognition of a mother's call by her pup is an important factor in allowing her to go to sea

Isabelle Charrier, biologist

The mother needs to hunt for fish a few days after the pup is born. She delays her first fishing trip until after the pup has learnt her voice.

When she returns, after weeks at sea, she locates her pup among many others in the rookery by calling out.

French scientists studying fur seals living on the remote Amsterdam Island off Antarctica found that pups acquired the ability to recognise their mother's call when they were two to five days old.

Fish hunt

The mothers rear the pups for the first 10 months of life. But they spend much of this time searching for fish in the vast hunting grounds of the Indian Ocean.

They may be gone for two to three weeks at a time, returning to dry land to feed their pups for three to four days.

The first fishing trip takes place about a week after birth, so the pup has to be able to recognise its mother's call almost immediately.

Remarkably, the mothers are reunited with their pups on their return to land in seven to 12 minutes.

Survival instinct

"In colonial mammals, the ability of pups to recognise their mother's voice is crucial for their survival as, in most species, females only feed their own offspring," say the team in the scientific journal Nature.

"The mother's departure date is linked to the pup's ability to recognise her voice," they add.

"This supports the idea that recognition of a mother's call by her pup is an important factor in allowing her to go to sea."

The work was carried out by biologists at the Laboratoire de Biologie Animale, Universite Jean Monnet, France.