Marine mammals
Northern fur seal
Callorhinus ursinus
Able to sleep at sea by folding its flippers out of the water like sails, it spends nearly ten months a year at sea, far from any coast.
🗺️ Geographic range
The North Pacific, from the Pribilof Islands in Alaska to Japan.
📊 Population
Global population estimated by the IUCN at about 1.1 million individuals, declining since the 1970s for reasons still debated (food competition, oceanographic changes).
⚠️ Threats
Decline with causes still debated
Declining since the 1970s for reasons not conclusively established: food competition with fisheries and oceanographic changes have been suggested, without a single confirmed cause.
Source: IUCN — Red List of Threatened Species
Habitat
- Pacific Ocean · High seas / open water · Epipelagic zone · Permanent
Behaviour
- Diet
- Pelagic fish and squid, hunted at night near the surface.
- Hunting
- Repeated dives, sometimes at night, to follow the vertical migration of zooplankton and its prey.
- Reproduction
- Massive gatherings on a few islands for breeding, the rest of the year spent at sea.
Physiology
- Anatomy
- Thick insulating fur, the densest in the animal kingdom.
- Adaptations
- Can sleep at the surface by folding its front and rear flippers out of the water, a posture called "sailing".
🔗 Web of marine life
Predators
⚡ Its extraordinary abilities
- Can sleep at sea by folding its flippers out of the water like sails
- The densest fur in the animal kingdom, up to 300,000 hairs per square centimetre
🏆 Records
The densest fur known in a mammal
Up to 300,000 hairs per square centimetre.
If you cross paths with this animal…
Risk: Low.
Behaviour: Wary at sea, can become territorial on breeding colonies.
Advice: Keep your distance from colonies during the breeding season.
💡 Did you know?
- Spends about ten months a year at sea without ever touching land.
- Its fur has up to 300,000 hairs per square centimetre, a record among mammals.