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 The Pinnipeds: Seals, Sea Lions, and Walruses

The word pinniped means fin or flipper-footed and refers to the marine mammals that have front and rear flippers. This group includes seals, sea lions, and walruses. These animals live in the ocean but are able to come on land for long periods of time. Millions of years ago, the ancestors of pinnipeds lived on land. These were probably weasel or bear-like animals that spent more and more time in the ocean and eventually adapted to this marine environment. There are three families of pinnipeds: phocids (seals), otariids (sea lions) and odobenids (walruses).

Earless Seals or True Seals
Phocids are sometimes referred to as earless seals or true seals and can easily be identified by looking at their ears and flippers. They have ear holes but no external ear flaps. They also have small front flippers and move on land by flopping along on their bellies. At sea, true seals move their rear flippers back and forth like a fish's tail to propel themselves through the water.

Eared Seals
Another family of pinnipeds are the otariids, sometimes referred to as eared seals. This family includes sea lions and fur seals. You can recognize these animals by their flippers and ears. Unlike true seals, they have external ear flaps. Their front flippers are large, and on land they are able to bring all four flippers underneath their bodies and walk on them. In the water, they swim using their front flippers like oars.

Fur seals, in spite of having the word “seal” in their name, are actually closely related to sea lions. They have longer flippers than sea lions, along with a rich luxuriant coat of fur that was so prized by hunters that it brought them to the brink of extinction in the 19th century.

The third family of pinnipeds is the walrus (odobenids). Both males and females have tusks and vacuum-like mouths for sucking up shellfish from the ocean floor. They have air sacs in their neck that can inflate to allow them to float as if they were wearing life preservers. Walruses are one of the largest pinnipeds, with males reaching over 3,000 pounds (1,360 kg). They live in the North Atlantic and Pacific Oceans, in the arctic region. Walruses are protected under U.S. and Canadian laws, but limited hunting by the Inuit people is allowed.

The Pinnipeds of the California Coast
There are 34 extant species of pinnipeds in the world today, including 16 species of eared seals and 18 species of true seals. The following six species of pinnipeds can be found along the California coast:

Pacific harbor seal (Phoca vitulina)
Harbor seals are the smallest of California pinnipeds, with spotted fur and colorization that varies from white to dark brown. They tend to stay near the shore, in subtidal and intertidal zones, and can often be seen on floating docks or sheltered beaches. Their range within California extends along the entire coast of the state. Learn more...

Northern elephant seal (Mirounga angustirostris)
Northern elephant seals are grayish and tan in color and only come onshore to mate, give birth, and molt (shed) their fur. Males and females are very different in size and appearance. Female elephant seals reach up to 1,300 pounds (600 kg). Males can grow up to 4,500 pounds (2,000 kg), and they develop a large nose or proboscis that looks like an elephant's trunk. Learn more...

California sea lion (Zalophus californianus)
California sea lions have brown fur, act playful, like to stay together in large groups, and sound like barking dogs. You can often see them hauled out on offshore rocks or floating together in large groups called "rafts." Males can weigh up to 800 pounds (360 kg), while females may weigh up to 220 pounds (100 kg). Learn more...

Steller sea lion (Eumetopias jubatus)
The largest otariid species, Steller sea lions can weigh over 2,000 pounds (910 kg). Most of them live in Alaskan waters, but about 500 live in California. The population was in severe decline, but has since recovered enough that the subspecies found in the eastern Pacific (Eumetopias jubatus monteriensis), was delisted from the Endangered Species List in 2014. Learn more...

Northern fur seal (Callorhinus ursinus)
The most common species of fur seal seen in California is the northern fur seal. They are pelagic animals, spending most of their lives far offshore. As their name implies, they are very furry, with over 300,000 hairs per square inch. The northern fur seal population has been in decline in recent years and they are listed as "vulnerable" under the U.S. Endangered Species Act. Learn more...

Guadalupe fur seal (Arctocephalus townsendi)
Another fur seal, the Guadalupe fur seal, is found in Mexico and sometimes off the California coast. Once there were many of them in California, but they came close to extinction due to extensive hunting for their fur. With protection from the Mexican and U.S. governments, there are now estimated to be over 7,400 Guadalupe fur seals. Learn more...


Shop our online gift store and help The Marine Mammal Center care for our sea lion patients!

Wonderfully illustrated, this Pinnipedia Poster shows all the pinniped species of the world.

Guide to Marine Mammals of the World, a detailed guide to our pinniped pals from the National Audubon Society.

Threatened Species Adoptions and Totebag: 3 adoptions and an earth-friendly totebag.


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