Northern Fur Sealキタオットセイ

Callorhinus ursinusVU— Vulnerable

The northern fur seal is a wide-ranging eared seal of the North Pacific, Bering Sea, and Sea of Okhotsk, with roughly half of its 1.1 million individuals breeding on Alaska's Pribilof Islands. Males grow dramatically larger than females and develop a mane-like ruff during the breeding season. Once hunted heavily for its fur, the species is now protected under international treaties but remains listed as Vulnerable, with the Pribilof population still classified as depleted.

Northern Fur Seal (reference photo)
Photo: U.S. Fish and Wildlife Service / Public domain / Source / cropped

Species Data

Classification
Carnivora / Otariidae Source
Distribution
Ranges across the North Pacific, Bering Sea, and Sea of Okhotsk from southern Japan to Baja California; an estimated 1.1 million individuals exist, with roughly half breeding on Alaska's Pribilof Islands. Source

Did You Know?

  • Males exhibit extreme sexual dimorphism, growing 4.5 times heavier than females and developing a mane-like ruff of fur around the neck during the breeding season. Source
  • The 1911 North Pacific Fur Seal Convention is regarded as the first international treaty aimed at wildlife conservation. Source
  • With the exception of the San Miguel Island population, northern fur seals migrate long distances south for the winter. Source

Where to See This Species

3 facilities · 0 individuals

How to tell Sea Lions, Seals, Fur Seals, and Walruses apart →

ふくしま海洋科学館 (Fukushimakaiyoukagakukan)FukushimaOpened in 2000

公式に飼育個体を紹介。野生保護の実績を持つ。 Source

市立玉野海洋博物館 (Shiritsu Tamanokaiyou Hakubutsukan)OkayamaOpened in 1953

渋川マリン水族館として展示。西日本では希少な飼育館。 Source

青森県営浅虫水族館 (Aomorikeneiasamushi Suizokukan)AomoriOpened in 1983

2018年に三沢海岸で保護した個体を含め複数頭を飼育。 Source

Conservation Story

Conservation Status

IUCNレッドリストでVulnerable(危急種)に分類されている。プリビロフ諸島個体群は特に「Depleted(枯渇)」に指定されており、1970年代以降産仔数が約50%減少した。

Habitat

北太平洋、オホーツク海、ベーリング海の亜寒帯海域とその周辺の島々を繁殖地とする。

Threats

Conservation & Breeding Efforts

Sources

ja.wikipedia.org en.wikipedia.org

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FAQ

Why is the northern fur seal considered Vulnerable?
Despite international protection since the early 20th century, its main breeding population on the Pribilof Islands has declined roughly 50% in pup production since the 1970s, and the causes remain debated among researchers. Source
How different in size are male and female northern fur seals?
Males are dramatically larger, reaching up to 270 kg compared to roughly 50 kg for females — one of the most extreme size differences among seals. Source
What international agreement helped protect northern fur seals?
The 1911 North Pacific Fur Seal Convention, the first international wildlife conservation treaty, restricted commercial hunting, and commercial harvesting was banned entirely by 1985. Source

Source: ja.wikipedia.org en.wikipedia.org www.iucnredlist.org