Mammals
Northern Fur Seal
Callorhinus ursinus · also called northern fur seals
Packed onto a remote Pribilof Island rookery alongside thousands of others, a northern fur seal carries fur so densely packed that a single square inch holds several hundred thousand individual hairs, a density that once made this species a prime target of the international fur trade.
Overview
The northern fur seal, Callorhinus ursinus, is a dense-furred eared seal native to open ocean waters of the North Pacific and Bering Sea, breeding primarily on remote islands including the Pribilof Islands of Alaska. Its record-breaking fur density, capacity for walking on land using rotated hind flippers, and history of severe depletion by commercial hunting make it one of the more conservation-significant marine mammals found in the North Pacific.
Fur too valuable for its own good
The very trait that helps the northern fur seal survive frigid ocean waters, an almost unmatched density of insulating fur, also made it one of the most heavily targeted marine mammals in commercial hunting history.
Status
Vulnerable and decreasing, having partially recovered from severe historical overhunting but continuing to face pressure from changing prey availability and ocean conditions at key breeding rookeries.
Northern Fur Seal: common questions
Why was the northern fur seal so heavily hunted historically?
This species has the densest fur documented in any mammal, with several hundred thousand hairs packed into a single square inch of skin, an exceptional insulating quality that made its pelt especially valuable commercially and drove intensive hunting throughout the 18th and 19th centuries.
How is the northern fur seal different from a true seal?
This species is an eared seal capable of rotating its hind flippers forward, allowing it to walk and even climb on land, unlike true seals such as the harbor seal, which can only move on land by humping and wriggling along on their bellies.
Why is the northern fur seal still considered Vulnerable despite past protections?
Although international agreements introduced protective hunting limits that allowed some recovery from historical overhunting, populations at key breeding rookeries have continued to show a decreasing trend in recent decades linked to changes in prey availability and ocean conditions, keeping the species classified as Vulnerable.
Where does the northern fur seal spend most of its time?
This species spends the vast majority of its life in the open ocean waters of the North Pacific and Bering Sea, coming ashore mainly to breed and give birth on a limited number of specific remote island rookeries, including the Pribilof Islands of Alaska.