Northern Fur Seal (Callorhinus ursinus)


Family:                    Otariidae

Status:                     Vulnerable.

Size:                        Length 5 to 7 ft., weight 90 to 600 lbs.

Diet:                        Piscivore.

Characteristics:        Social.

Area:                       Waters off western Canada & the U.S., Japan and eastern Russia.

Offspring:                One pup per year.



·         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.” 

·         Fur seals are known and named for their thick fur, which has 300,000 hairs per square inch. 

·         Females and young males look black when wet.



Adult male fur seals are much larger than females, and have lighter coloured fur. In fact, the two genders are so different in appearance that it was once believed they were two different species. Fur seals feed mostly during the night, and eat a large variety of small fish and squid. They can dive up to 600 feet under the water’s surface when searching for food. They appear 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. Adult males stay in the north during the cold winter months, while females and juveniles travel annually to warmer waters in the south.



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’re sick. They were once hunted for their meat and blubber as well as their gorgeous fur, which was extremely popular in coats worn at football games in the 1930s and 1940s. Northern fur seals were hunted extensively since their discovery in the mid-1700s, and their numbers dropped from millions to less than one million. In 1911, the North Pacific Fur Seal Convention was formed and they are now protected under the Marine Mammal Protection Act as a “depleted species.” Unfortunately, the population is believed to be further declining from lack of food due to commercial fishing and many seals die when they become tangled in fishing gear.



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 with a day or two of arriving. Any number from 20 to 100 females establish themselves in each territory, and the male mates with many of them. The pregnant females usually mate again seven to ten days after giving birth. The mating season lasts one to two months, during which time the males fast, losing up to 20 percent of their body weight. Pups weigh between 10 to 12 pounds at birth (males are approximately 2 pounds heavier than the females) and have a black pelt that gradually lightens to dark brown. Pups are nursed for three to four months. Twelve percent of northern fur seal pups die in their first month from anaemia, caused by hookworm, and only ten to fifty percent of pups live to reach a year. Females don’t begin to mate until they’re three to five years of age, and from eight to thirteen, they usually give birth once per year. Males are sexually mature at six, but aren’t large enough to defend a territory until nine or ten. Female seals have been known to live to 26, while the record for a male is 17 years of age.