The Northern Fur Seal (Callorhinus ursinus) is an eared seal found along the north Pacific Ocean, the Bering Sea and the Sea of Okhotsk. It is the largest member of the fur seal subfamily (Arctocephalinae) and the only species in the genus Callorhinus. Northern fur seals have extreme sexual dimorphism, with males being 30-40% longer and more than 4.5 times heavier than adult females. The head is foreshortened in both sexes because of the very short down-curved muzzle, and small nose, which extends slightly beyond the mouth in females and moderately in males. The pelage is thick and luxuriant, with a dense underfur that is a creamy color.
Ten Facts about Northern Fur Seal
- Male and female seals come together only during breeding season. Once they are mature, males never stray far from the breeding area. Females, however, make an annual migration to hunt in waters as far south as California.
- The northern fur seal spends most of its life hunting for food in the north Pacific. Its main food is fish, although it also eats squid and crustaceans.
- Males can be as large as 2.1 m and 270 kg. Females can be up to 1.5 m and 50 kg or more. Newborns weigh 5.4-6 kg, and are 60-65 cm long.
- Seals aggregate on traditional breeding grounds (rookeries) in May.
- Like all other otariids, northern fur seals are polygynous, with some males breeding with up to 50 females in a single breeding season.
- After remaining with their pups for the first eight to ten days of their life, females begin foraging trips lasting up to a week. These trips last for about four months before weaning, which happens abruptly, typically in October.
- Peak mating occurs somewhat later than peak birthing from late June to late July.
- They attain sexual maturity at the age of 3 years, while there gestation period is 93 - 110 days.
- They can live up to 22 years.
- They can give birth 1 - 4 cubs at a time.
