Learn more about the marine mammals commonly found on Oregon beaches.

What is a marine mammal?

Three major types of marine mammals are found in the Pacific Northwest: pinnipeds (seals and sea lions), cetaceans (whales, dolphins and porpoises), and sea otters. They are all air-breathing, warm-blooded mammals that depend on the marine environment for their survival.

Three types of marine mammals in Oregon

Pinnipeds include seals, sea lions and walruses. They are semi-aquatic mammals that divide their time between foraging at sea and coming ashore to rest, mate, give birth, suckle their young, and/or molt (shed their hair).  Pinnipeds are characterized by a coat of fur, whiskers, and fore and hind flippers. They are derived from a bear-like ancestor thought to have lived about 23 million years ago.

There are two families of Pinnipeds that occur in Oregon. Phocids (seals) do not have external ear flaps, they have short front flippers with claws on their ends, and move on land by humping along on their bellies. Otariids (sea lions and fur seals) do have external ear flaps, long front flippers, and the ability to rotate their hind flippers under their pelvis to walk on all fours on land.

Cetaceans include any whale, dolphin or porpoise. Cetaceans are divided into two groups: Mysticetes (baleen whales) and Odontocetes (toothed whales). It is never normal to see whales, dolphins, and porpoises on the beach. Their bodies are not adapted to survive out of water for long periods.

Cetaceans are fully aquatic mammals, and can be differentiated from fish by the presence of a blowhole on top of the head and horizontal tail flukes that move up and down (fish have vertical tails that move back and forth). They are derived from a hoofed ancestor thought to have lived about 50 million years ago. Jump to Cetaceans


Sea otters are members of the weasel family that have adapted to life almost entirely in the water. Sea otters have short, paddle-like tails and webbed feet. They spend most of their time floating on their backs in the water. 

River otters may be mistaken for sea otters, as they sometimes venture into the marine environment. But sea otters are larger than river otters, and do not generally run around on land like river otters tend to do.



Pacific harbor seal * California sea lion * Steller sea lion * Northern elephant seal


Pacific Harbor Seal

(Phoca vitulina richardi)

Adult Harbor Seal

Adult harbor seal

Newborn harbor seal pup


  • No external earflaps
  • Color variable (gray to tan to brownish-black), with dark spots or mottling
  • Pups are gray to tan (white coat of lanugo fur typically indicates premature birth)


Maximum Measurements
  Length  Weight
Male 6'3" (1.9 m) 370 lb (170 kg)
Female 5'7" (1.7 m)

290 lb (130 kg)

It is normal for harbor seals to rest on land, although they usually choose places that are far from people and dogs, such as on offshore rocks or on a remote sand spit.

Harbor seal pups are frequently found alone on the beach. They are usually not stranded, but simply resting (as all baby mammals must do) and waiting for their mothers to come back ashore to nurse them. Adult female seals are shy and unlikely to rejoin a pup if there is activity nearby. They may only return to suckle their pup at night when people are not around. It is very important not to interfere with this process, and especially not to move a pup from where it is receiving care from its mother. Learn more

California Sea Lion

(Zalophus californianus)



  • Color dark brown; juveniles and females lighter
  • Extreme sexual dimorphism, males much larger than females
  • Males with prominent sagittal crest (light colored point on top of head), muscular neck
  • Bark-like vocalizations
Maximum sizes of California sea lions
  Length Weight
Male 7’10” (2.4 m) 860 lb (390 kg)
Female 6’7” (2.0 m) 240 lb (110 kg)

Sea lion on beach, barking

Adult male California sea lion

Most of the California sea lions found in Oregon are adult males. It is rare for females to travel north of their primary range off the coast of southern California and Baja California. These boisterous animals are quite common in bays and harbors, often hauling out on floating docks and jetties. Strandings are common on ocean beaches during the fall and spring, when large numbers of adult males are making lengthy migrations to and from the breeding areas of southern California.

Steller Sea Lion

(Eumetopias jubatus)


  • Broad front flippers
  • Color light brown to blond, darker ventrally than dorsally
  • Adult males much larger than females; thick mane of fur around neck
  • No sagittal crest on head
Maximum size of Steller sea lions
  Length Weight
Males 11’ (3.3 m) 2,400 lb (1,100 kg)
Females 9’6” (2.9 m) 770 lb (350 kg)

The Steller, the largest of the sea lions, is typically found near remote reefs and rocky haul out areas, particularly off the south coast, as well as in the lower Columbia River. Strandings of males and females occur sporadically, throughout the year, on ocean beaches.

Steller Sea Lion Close Up

Adult male Steller sea lion


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.

Northern Elephant Seal

(Mirounga angustirostris)


  • Adult males much are larger than females
  • Adult males have large inflatable proboscis
  • Color gray to brown with no markings
  • Black whiskers
  • “Catastrophic Molt” occurs annually April-August
Maximum size of Northern elephant seals
  Length Weight
Males 13’6” (4.1 m) 4,400 lb (2,000 kg)
Females 10’ (3 m) 1,300 lb (600 kg)

Although adult elephant seals are rarely reported in Oregon, juvenile elephant seals routinely come ashore on Oregon beaches, typically during the spring/summer molting season. Elephant seals go through an annual molting process, in which they come ashore to shed their hair and skin. This natural process takes weeks to complete, and is often marked by irregular breathing, weepy eyes, runny noses, and damaged-looking skin. But as bad as molting animals may look, they are going through a normal and necessary process, and are usually are not stranded.

Molting juvenile elephant seal

Molting juvenile elephant seal


During the 'catastrophic molt' elephant seals often appear sick, but they are undergoing a normal process.


harbor porpoise * gray whale

Harbor Porpoise

(Phocoena phocoena)


  • Robust body with a short beak
  • Color is dark gray dorsally, lighter gray laterally; throat and belly mostly white
  • Medium-sized dorsal fin is triangular in shape, located at mid-body
  • Teeth are spade shaped (flat on top), not pointed
Maximum size of harbor porpoises
  Length Weight
Male 5’2” (1.57 m) 134 lb (61 kg)
Female 5’6” (1.68 m) 168 lb (76 kg)

Harbor porpoises are often found close to Oregon beaches in spring and summer. Due to their small size, they are often mistaken for “baby whales.” If found alive on shore, they can sometimes be successfully returned to water.

Stranded harbor porpoise calf

Harbor porpoise calf

Dead porpoises are often scavenged very quickly by birds, so it is important to report and protect porpoise carcasses quickly so that valuable information about these animals is not lost.

Gray Whale

(Eschrichtius robustus)


  • Large body with mottled gray coloration
  • Head appears narrow and pointed
  • Mouth contains short (about 10 inches long), light colored baleen plates
  • No dorsal fin, but a hump followed by a series of bumps running caudally down back
  • Barnacles and whale lice grow over surface of body, particularly on the head
Maximum size of gray whales
Length Weight
49’ (15 m) 80,000 lb (35,000 kg)

Gray whales are very common off the Oregon coast, particularly during periods of migration between the summer foraging grounds in the high arctic and the winter calving waters of Baja California.

Stranded adult gray whale

Adult gray whale


Contrary to common belief, gray whales feeding close to shore are not in danger of stranding. They are bottom feeders, and frequently come extremely close to shore (near rocky cliffs and in the surf zone) to forage. Some gray whales dive near crab pot buoys to feed on mysid shrimp found near crab traps. This activity gives the mistaken impression that the whales are entangled in fishing gear.