Seals & Sea Lions

Seals and sea lions belong to a group of marine mammals called pinnipeds, which means fin or flipper-footed. These animals live in the ocean, but are able to come on land for long periods of time. Some species have evolved the ability to hold their breath for up to two hours and dive to depths of more than 6,500 feet when looking for food.

There are two families of pinnipeds: Phocids and Otariids. Phocids are also known as earless seals or “true” seals. 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, these seals move their rear flippers back and forth like a fish's tail to propel themselves through the water. Phocids include the harbor seal and Hawaiian monk seal.

Otariids, also known as eared seals, include sea lions and fur seals such as the Steller sea lion and the northern fur seal. 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. Otariids propel themselves in the water by paddling their front flippers and using their rear flippers to steer. 

All seals and sea lions are protected under the Marine Mammal Protection Act, and some are also listed under the Endangered Species Act. Together with our partners, we work to study, protect, and conserve these unique marine mammals and their habitats.


Species News

Two stranding responders carry a stranded harbor porpoise away from some rocks A harbor porpoise is retrieved from the rocks at Odiorne Point State Park, New Hampshire. Credit: Seacoast Science Center
Spotted, gray harp seal on sandy shore moving towards the ocean water. "Seuss," a juvenile harp seal, was released on Blue Shutters Beach, Rhode Island, following successful rehabilitation at Mystic Aquarium. Credit: Mystic Aquarium
A mother Hawaiian monk seal and her pup lay side by side on a sandy beach. Hawaiian monk seal RK80 (Keolakai) gave birth to her first pup, Makana, in February 2024 on Oʻahu. Credit Hawaiʻi Marine Animal Response (NOAA Fisheries Permit #24359)
Aerial view of Bogoslof Island in June 2022 showing the impact of the volcanic eruption from 2019 Aerial survey imagery from June 2022 along with a white outline showing the former size in 2019. Erosion has changed the island dramatically since it tripled in size after the eruptions in 2016-2017. Credit: NOAA Fisheries/Alexey Altukhov and Burlyn Birkemeier.

Multimedia

Cape Shirreff field camp against a backdrop of mountains in Antarctica. Credit: NOAA Fisheries Cape Shirreff field camp on Livingston Island, one of the most breathtaking places in Antarctica. Credit: NOAA Fisheries
A Hawaiian monk seal pup lays in the sand A young, female Hawaiian monk seal pup, identified as "PM6," lying in the sand at Kalaupapa, Molokai in 2017. This is the fourth pup of mom "RI25." Credit: NOAA/Tracy Mercer (Permit #16632-02).

Research

Peer-Reviewed Research

Publications by Northeast Passive Acoustics Branch Staff

We regularly publish their findings in scientific journals and Center-produced documents.

Cape Shirreff Situation Reports 2023-2024

These reports highlight science activities and events from the U.S. Antarctic Marine Living Resources Program Field Camp at Cape Shirreff, Livingston Island, part of the South Shetland Islands of Antarctica

Peer-Reviewed Research

First Demographic Parameter Estimates for the Mediterranean Monk Seal Population at Madeira, Portugal

We provide the first comprehensive demographic assessment of the Endangered Mediterranean monk seal…

Passive Acoustic Research in the Atlantic Ocean

Marine mammals and many fish produce and receive sound in the ocean. In an environment where vision is limited, hearing is one of the most important senses. These animals rely on sound for navigating, socializing, establishing dominance, attracting…

Viewing Marine Life

Watching marine animals in their natural habitat can be a positive way to promote conservation and respect for animals and their environment.

On Shipwreck Beach on the south coast of Kauai, Hawaii, an endangered Hawaiian monk seal takes a nap on the beach. The sign in the foreground instructs people to walk around the seal.

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