Our northern fur seals, the stars of Life According to Fur Seals at the New Balance Foundation Marine Mammal Center, are famously known for their thick fur. They have many other special adaptations as well.

northern fur seal


Male and female fur seals vary greatly in size—this is called sexual dimorphism. While female northern fur seals can grow up to 4.5 feet in length and weigh up to 120 pounds, the males can grow as long as 7 feet and weigh a whopping 600 pounds.

northern fur seal flipper


Fur seals have bones that reach halfway down their hind (rear) flippers. Past this point, the flippers are made of cartilage, allowing seals to reach anywhere on their bodies to groom their fur coats. They can also rotate their flippers underneath themselves to walk on land.

northern fur seal fur


With about 300,000 hairs per square inch, the fur of a northern fur seal is the second thickest in the animal kingdom; the sea otter has the thickest fur. They have two coats of fur. The dark outer fur is very dark, while the undercoat is a peach color. Their fur is so thick, that water never reaches their skin. This allows fur seals to stay warm as they hunt for food in the frigid waters of the Northern Pacific Ocean.

northern fur seal whiskers


Fur seals use their whiskers, or vibrissae, to feel for vibrations in the water to hunt fish, avoid predators, and explore their environment.

northern fur seal ear


Like sea lions, northern fur seals belong to the “eared seal” family (Otariidae). They have great hearing.

northern fur seal


While northern fur seals don’t have color vision, they see in shades of black and white and have good eyesight.

northern fur seal teeth


Northern fur seals don’t chew their food. They swallow it whole. If a fish is too big to gulp down, the seals hold it tightly with their very sharp teeth and whip their head from side to side with such force the fish tears apart into bite-size pieces. Pinnipeds (a group that includes seals, sea lions, and walrus) have an average of 34 to 38 teeth, while humans have 32.

northern fur seal nails


Fur seals have three nails on each hind flipper. This helps them groom that thick fur. They can even bend their hind flipper in half to make full use of these nails.

Learn more about northern fur seals by visiting Central Wharf or reading more about them here: