What is a fur seal, anyway?

Fur seals are pinnipeds, which include seals, sea lions, and walrus.  “Pinniped” means flipper-footed.  Fur seals belong to the otariid [oh-tah-RYE-id] family, or eared seals, which includes the fur seals and sea lions.  This family is different from the true seals (phocids [FOE-sids]), and there are three main ways to tell them apart:

1)  Their ears.  Fur seals and sea lions have ear flaps (called “pinnae”) that you can see on their heads.  True seals have ears, but you can’t see their location from afar.  There is just a little hole on each side of their head that shows you where their ears are.

2)  Their flippers.  Fur seals and sea lions have long front and back flippers, and they can tuck their back flippers beneath them to walk (or waddle) on land.  True seals have stubby front flippers and cannot tuck their back flippers for walking.  To move on land, true seals move along by undulating their blubbery bodies like an inchworm.

3)  Their swim.  Fur seals and sea lions swim with their front flippers.  They move the flippers in a figure-eight motion, the same movement that a hummingbird uses to fly.  In fact, they do look like they are flying underwater when you watch them swim!  True seals use their back flippers to swim, moving their webbed feet (and the lower third of their bodies) side-to-side to move through the water.

 Northern fur seal pup (eared seal).

Northern elephant seal pup (true seal).

What about the walrus?  Walruses are in their own family, and they have a mixture of the characteristics listed above.  They do not have external ear flaps, but they can tuck their back flippers to walk on land.  Like true seals, they use their back flippers to swim.  The most distinctive characteristic of walruses is their tusks.  Both males and females have tusks, and they use them as defense against polar bears and other walruses.

Walrus (Odobenus rosmarus).

What is the difference between a fur seal and a sea lion?  They are in the same family, and share the characteristics of eared seals listed above.  The difference is their insulation.  Fur seals have thick, waterproof fur, which they use to keep warm in the water.  Sea lions have short, non-waterproof fur, and instead rely on blubber for insulation.  So fur seals aren’t true seals – they are sea lions with a fur coat!