Southern sea otter

At the Aquarium

Keeping our sea otters busy is a full time job, and an important one too. Giving the otters fun toys and teaching them new behaviors, like walking onto a scale or holding a target with their paws, helps keep them healthy and happy.

It's fun for our staff too!  

Natural History

To stay warm in chilly ocean waters, otters wear the world's densest fur. At its thickest, this two-layer fur is made up of more than a million hairs per square inch. (You've probably got 100,000 hairs or less on your whole head!)

To keep their luxurious coats waterproof, otters spend many hours a day cleaning and grooming. Such good grooming coats their fur with natural oils from their skin and fluffs it with insulating air bubbles.


Sea otters once thrived from Baja California to the Pacific Northwest of North America through Alaskan and Russian waters and into Japan before hunters nearly exterminated them in the 1700s and 1800s. The California population has grown from a group of about 50 survivors off Big Sur in 1938 to just over 2,000 today. Although their numbers have increased, sea otters still face serious risks: oil from a single tanker spill near San Francisco or off the central coast could wipe out the entire California sea otter population.

The Aquarium partners with state, federal and academic researchers to study otters in the wild. The more we learn about otter behavior, biology and health, the better we can protect these threatened animals.

Cool Facts

An otter may hunt on the seafloor, but always returns to the surface to eat. Floating there on its back, it uses its chest as a table. (And if dinner's a crab or clam, the otter may use a rock to crack open its prey.)

To help it stay warm in cold water, a sea otter burns calories at nearly three times the rate you do. An otter fuels its fast metabolism by eating up to a quarter of its weight in food a day. (A 150-pound person would have to eat 35 to 40 pounds of food a day to match that!)

An otter's coat has pockets—flaps of skin under each front leg. An otter uses them to stash prey during a dive, which leaves its paws free to hunt some more.