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

Six temporary white tents setup along the beach with an inflatable boat resting on the shoreline. This photo was taken from a small boat after the temporary field camp was setup at the beginning of the field season in May 2022. Field camp at Manawai (Pearl and Hermes Reef). This temporary home to four NOAA biologists is similar to the other camps throughout the Papahānaumokuākea Marine National Monument. Credit: NOAA Fisheries/Laura McCue.
Gray whales swimming Gray whales were nearly hunted to extinction by commercial whaling. Protections under the MMPA, ESA, and the end of commercial whaling have allowed the species to recover. Credit: NOAA Fisheries (Permit #19091).
Two harbor seals in their pool. They are hauled out of the water on a wooden pier in the pool. In the foreground, a young seal is on her belly, head to the left, tail arching to the right. Deep scarring is visible on her forehead and the side of her face. In the background a large male lies on his belly just behind the young seal, facing the camera head on. Pool toys used in training are floating nearby. Harbor seals Kitt and Bubba hauled out in their pool at the Woods Hole Science Aquarium. Credit: NOAA Fisheries/Hannah Colwell


NOAA Ship Oscar Elton Sette off Maui in 2004. NOAA Ship Oscar Elton Sette off Maui in 2004. Homeported in Honolulu, Hawaii, NOAA Ship Oscar Elton Sette is a multipurpose oceanographic research vessel that conducts fisheries assessments, physical and chemical oceanography research, marine mammal and marine debris surveys. The ship operates throughout the central and western Pacific Ocean. Credit: NOAA/Ray Boland.


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