Northern Fur Seal (Callorhinus ursinus)


Class: Mammalia
Order: Pinnipedia
Family:    Otariidae
Size:    Length: 4.5 to 7 feet (1.4 to 2.1 m)
Weight: 90 to 600 pounds (30 to 272 kg)
Diet: A variety of small fish and squid
Distribution: Waters off western Canada & the U.S., Japan and eastern Russia
Young:  1 pup per year
Animal Predators:  Sharks, killer whales, foxes and Steller’s sea lions
IUCN Status: Vulnerable
Terms: Young: Pup
Lifespan: Female seals up to 26; males up to 17 years of age.



·         Fur seals were first described scientifically by Georg Wilhelm Steller in 1742.

·         They were first named “sea bears” by Europeans, and their scientific name also means “bear-like.” 

·         12 percent of northern fur seal pups die in their first month from anaemia, caused by hookworm.



Adult male fur seals are much larger than females, and have medium grey or dark brown coloured fur, while females have medium to dark silver coloured fur. In fact, the two genders are so different in appearance that it was once believed they were two different species. They have thick under fur, which has over 350,000 hairs per square inch. Females and young males look black when wet.



Male and female northern fur seals have very different migration patterns. Females and juveniles travel annually to the warmer southern waters of places such as Southeast Alaska, California and Japan, while males males only go as far south as the Gulf of Alaska and the Southern Bering Sea. The total world population of northern fur seals is estimated at less than one million, with three quarters of those breeding on the Pribilof Islands of St. George and St. Paul in the southern Bering Sea. Other breeding sites are located on the central Kuril Islands, Tyuleniy Island in the Okhotsk Sea, the Commander Islands, Bogoslof Island in the Aleutian Islands, and San Miguel Island in southern California. They only come to the islands for breeding, and remain in the open ocean otherwise, unless they are sick. 


Feeding Habits

Fur seals feed mostly during the night, and eat a large variety of small fish and squid. They can dive up to 754 feet (230 m) under the water’s surface when searching for food. 



Males are the first to arrive in the breeding areas during mating season, and establish their own territories. When the females arrive in mid-June, the pregnant ones give birth within a day or two of arriving. From 20 to 100 females establish themselves in each territory, and the male mates with many of them. The pregnant females usually mate again five to seven days after giving birth. The mating season lasts one to two months, during which time the males fast, losing up to 25 percent of their body weight. Pups weigh between nine and 14 pounds at birth (males are approximately two pounds heavier than the females) and have black pelts that gradually lighten to dark brown. Pups are nursed for three to four months. Females do not begin to mate until they are two to five years of age, and from eight to 13, they usually give birth once per year. Males are sexually mature at four to six years of age, but are not large enough to defend a territory until they are eight to 10 years of age. 



They are very playful and can be seen diving in and out of the water together. When at rest, fur seals float on the surface of the water. Male and female fur seals are only found together during mating season. 



They were once hunted for their meat and blubber as well as their fur, which was extremely popular in coats worn (especially at football games) in the 1930s and 1940s. Northern fur seals were hunted extensively since their discovery in the mid-1700s, during which time millions of northern fur seals were killed. In 1911, the North Pacific Fur Seal Convention was formed; it has since lapsed. Currently, the Pribilof/Bogoslof Islands population is protected under the U.S. Marine Mammal Protection Act as a depleted species.” Since 1993, northern fur seals have been protected in Canada by the Marine Mammal Regulations. However, the population is believed to be further declining from lack of food due to commercial fishing; also, many seals die when they become tangled in fishing gear.



Northern Fur Sea; Wildlife Fact File, IM Pub, US