Sea Otters: Puppies of the Sea

We are continuing our series on ocean life, written by WAVES Project volunteer Trina.


This aquatic member of the weasel family is found along the northern and eastern coasts of the Pacific Ocean in North America and Asia. The sea otter spends most of its time in the water but, in some locations, comes ashore to sleep or rest. Sea otters have webbed feet, water-repellent fur to keep them dry and warm, and nostrils and ears that close in the water. They weigh between 14 and 45 kg therefore the heaviest member of the weasel family. They are one of the smallest sea mammals. They can live up to 23 years. Sea Otters are cool.

Feeding Habits 

While floating on their backs they are often seen with a clam or mussel and a rock that has been grabbed from the ocean floor. Otters will place the rock on their chests, and breaks open the shellfish by smashing it on the rock. This reveals the tasty meal inside. They also eat other aquatic creatures like sea urchins, crabs, squid, octopuses, and fish. They also eat a lot for their size, adult sea otters can eat 25%-30% of their body weight in one day!

Relax Like an Otter

Sea otters often float at the water’s surface, lying on their backs in a posture of serene repose. They sleep this way, often gathered in groups. Otters sometimes float in forests of kelp, or giant seaweed. They tangle themselves in the seaweed to keep them from drifting out to sea. This makes them feel safe.

Caring for Babies

Females give birth to one pup and usually have their first pup at the age of four or five. Their pregnancies last four to five months. Pups can be born any time of year, but in California most are born between January and March, and in Alaska most are born in the summer. When born, the pups weigh from three to five pounds. Sea otters are the only otters to give birth in the water. Mothers nurture their young while floating on their backs. They hold infants on their chests to nurse them, and quickly teach them to swim and hunt.

Animal Facts

  • Scientific Name: Enhydra lutris nereis
  • Animal Type: Marine Mammals
  • Diet: crabs, snails, urchins, clams, mussels and other invertebrates
  • Size: Up to 4 feet (1.2 m) and up to 50 pounds (23 kg) for females and 70 pounds (32 kg) for males
  • Relatives: weasels, river otters, ferrets; Family: Mustelidea (sea otters are the only exclusively marine member of this family)
  • Habitat: Kelp Forest
  • They are in danger

They take care of their coats—it helps them to remain waterproof and insulated against the cold. Sea otters have thick underfur that traps air to form an insulating layer against the chilly waters (they have no insulating fat). This coat is invaluable to otters, but it has worth to some humans as well. Sea otters were hunted for their fur to the point of near extinction. Sea otters in California are a threatened species due to past over hunting for their beautiful fur. Although sea otters are protected now, they remain vulnerable, especially to oil spills. Unlike other marine mammals, sea otters do not have a blubber layer. Therefore, they rely on their fur to keep warm. If their fur is oiled, it loses its insulating qualities and the sea otters soon chill. Otters are also affected by the oil fumes or poisoned by eating food exposed to oil. Most sea otters quickly die in an oil spill. Several thousand sea otters died in the 1989 Exxon oil spill in Valdez, Alaska. Other threats to sea otters include infectious diseases, parasites, boat strikes, entanglements, and toxins. Today, sea otters are protected by law.


Sea otters once thrived from Baja California and around the Pacific Rim to Russia and Japan before fur 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 nearly 3,000 animals 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 would threaten the entire California sea otter population. The center of the population’s range—from Monterey Bay to south of the Big Sur coast—can’t support higher numbers of sea otters, so they need to keep expanding their range to find new areas with abundant food. Bites from white sharks is a major threat to sea otters in this area.

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


Live Sea Otter CamEnjoy Monterey aquariums sea otters as they frolic and swim.

Watch now

Quick Facts

  • 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!)
  • A sea 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.)
  • An otter’s coat has pockets—pouches of loose skin under each forearm. An otter uses them to stash prey during a dive, which leaves its paws free to hunt some more.
  • Unlike the sea otters found in Alaska, sea otters on California’s central coast don’t eat fish.

WAVES Project volunteer Trina contributes articles for the newsletter periodically. She is dedicated to preserving our oceans and the remarkable creatures that live in them. Trina – age 13