Northern fur seal

How it lives

Northern fur seals breed on crowded island rookeries. Older males arrive first, in May, and hold ground without feeding. Females arrive from about mid-June and give birth a few days later. One male may mate with up to about 50 females. Pregnancy lasts about a year because the fertilised egg pauses for about four months before it implants. Mothers make feeding trips of up to about a week and recognise their own pup by its voice. Pups nurse for 3 to 4 months, and weaning is abrupt, typically in October. In the wild, males live up to about 18 years and females up to about 27.

Where it goes

Northern fur seals spend the summer breeding season on a few island rookeries and most of the rest of the year at sea. In winter the animals move south. Seals from Russian rookeries regularly enter Japanese and Korean waters, and Alaskan animals travel along the eastern Pacific to British Columbia and as far south as Baja California.

We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.

Populations

The species was estimated at about 1.1 million animals, with roughly half breeding on the Pribilof Islands. NOAA reports the Eastern Pacific stock at 626,618 seals (2019) and the California stock at about 15,018 (2022). Pup production on the Pribilof Islands was the lowest in 100 years in 2016, and that stock has been listed as depleted under the US Marine Mammal Protection Act since 1988. In Russia, about 20 percent of the world population breeds on four rookeries on the Commander Islands, two on Bering Island and two on Medny Island, and one source gives 200,000 to 250,000 animals there. Other breeding groups are about 100,000 on Tyuleniy Island and 60,000 to 70,000 in the central Kuril Islands. I did not find a Russia-wide trend in the pages I read. The IUCN lists the species as Vulnerable (assessed 2015).