Mammals
Steller Sea Lion
Eumetopias jubatus · also called Steller's sea lion, northern sea lion
On a rocky rookery along the North Pacific coast, a massive male Steller sea lion roars a deep, resonant call across the colony, the largest sea lion species in the world defending territory within a population still recovering from a decline scientists have never fully explained.
Overview
The Steller sea lion, Eumetopias jubatus, is the largest sea lion species in the world, native to coastal and nearshore ocean waters across a broad range of the North Pacific, from California north through Alaska and across to Russia and Japan. Its imposing size, powerful roaring vocalisations, and dramatic, still only partly understood population crash in Alaska make it one of the more conservation-significant and scientifically puzzling marine mammals found in the North Pacific.
A giant with an unsolved mystery
Despite decades of research, the sudden collapse of Steller sea lion numbers across parts of Alaska in the late 20th century has never been fully explained, leaving this massive marine mammal at the centre of one of the North Pacific’s more persistent ecological puzzles.
Status
Near Threatened, with the western population segment still classified as Endangered under US law even as some other populations have stabilised or begun to recover.
Steller Sea Lion: common questions
Why did Steller sea lion populations decline so dramatically?
This species experienced a dramatic population decline across parts of Alaska in the late 20th century, and while researchers have proposed several contributing factors including changes in prey availability, increased predation, and competition with fisheries, the exact combination of causes behind the crash remains only partly understood.
How big is the Steller sea lion compared to other sea lions?
This species is the largest of all sea lion species in the world, with males considerably outweighing females and reaching sizes well beyond most other eared seal species, making it easy to distinguish by sheer scale where its range overlaps with smaller sea lion species.
How is the Steller sea lion different from a true seal?
This species is an eared seal capable of rotating its hind flippers forward, allowing it to walk and climb confidently on rocky shorelines, unlike true seals, which can only move on land by humping and wriggling along on their bellies.
Has the Steller sea lion recovered from its population decline?
Partially; some populations have stabilised or begun to recover since the crash, but the western population segment remains classified as Endangered under US law, contributing to the species' overall Near Threatened conservation status despite improvement in certain areas.