Pinnipeds are carnivores that have adapted to an amphibious marine existence. They forage at sea but most come ashore or onto ice at some time of the year to mate, give birth, suckle their young, or to molt. Many of their anatomical features reflect compromises needed to succeed in both marine and terrestrial environments. Externally, pinnipeds share many characteristics with terrestrial carnivores (fissipeds) due to their need for mobility on land.
Pinnipeds have four webbed flippers used to propel their spindle-shaped bodies. Their sensory organs are adapted to function in both air and water: large eyes and well-developed whiskers allow feeding in dimly lit water; tail and external ears are small, limiting drag. Pinnipeds have retained canine teeth but molars are modified for consuming prey whole. All have fur, which is shed or molted annually, but they are insulated primarily by blubber.
Pinnipeds are present in habitats ranging from ice to tropics, coastal to pelagic waters, and may live a migratory or sedentary existence. They are opportunistic feeders and consume their varied prey whole or in chunks. Many pinnipeds are capable of long, deep repetitive dives (to 4500 ft depths and 2 hours). This phenomenal diving ability is possible because of several physiological traits shared by cetaceans, such as high blood volume and reduced heart rate.
CALIFORNIA SEA LION (Zalophus californianus)
California sea lions are “eared seals” native to the West Coast of North America. They live in coastal waters and on beaches, docks, buoys, and jetties. They are easily trained and intelligent and are commonly seen in zoos and aquariums. California sea lions are playful, intelligent, and very vocal (sounding like barking dogs). Like all marine mammals, they are protected under the Marine Mammal Protection Act. Their population has been increasing since at least 1975, after protections were put in place under the MMPA.
https://www.fisheries.noaa.gov/species/california-sea-lion
STELLER SEA LION (Eumetopias jubatus)
The Steller (or northern) sea lion is the largest member of the family Otariidae, the “eared seals,” which includes all sea lions and fur seals. Steller sea lions are named for Georg Wilhelm Steller, the German surgeon and naturalist on the Bering expedition who first described and wrote about the species in 1742. While they are the only living member of their genus, they share parts of their range with a smaller related species, California sea lions. Steller sea lions' impressive low-frequency vocalizations sound more like roars than California sea lions’ barks. They also share parts of their range with another otariid: northern fur seal.
https://www.fisheries.noaa.gov/species/steller-sea-lion
HARBOR SEAL (Phoca vitulina)
Harbor seals are one of the most common marine mammals along the U.S. West and East Coasts. They are commonly seen resting on rocks and beaches along the coast and on floating ice in glacial fjords with their head and rear flippers elevated in a “banana-like” position. On land they move clumsily by flopping on their bellies in an undulating motion called gallumphing, but in the water they gracefully propel themselves with their rear flippers. Harbor Seals spend their lives close to shore hunting for small fish.
https://www.fisheries.noaa.gov/species/harbor-seal
ELEPHANT SEAL (Mirounga angustirostris)
The northern elephant seal is the largest of the “true” seals in the Northern Hemisphere. Adult males use their large, inflatable noses during the winter breeding season to resonate sound when vocally threatening each other. The largest colonies of northern elephant seals are found off southern California in the Channel Islands. They have one of the longest migrations of any mammal; some have been recorded traveling over 13,000 miles roundtrip.Northern elephant seals were once thought to be extinct due to commercial sealing in the 1800s. A small population survived in Mexico and the population began to steadily increase in the early 1900s. Today, robust populations of northern elephant seals in the U.S. and Mexico are derived from those few hundred individuals that survived in Mexico.
https://www.fisheries.noaa.gov/species/northern-elephant-seal