Seals are marine mammals belonging to the pinniped group, a name that means “fin-footed.” They are well adapted to life in the water, with streamlined bodies, flippers for swimming, and thick layers of blubber that help insulate them in cold oceans. While seals spend much of their time at sea, they must come ashore or onto ice to rest, molt, and give birth.
There are two main groups often referred to as seals: true seals (earless seals) and eared seals, which include sea lions and fur seals. True seals lack external ear flaps and move on land by wriggling on their bellies, while eared seals can rotate their hind flippers and walk more easily on land. Despite these differences, all seals share strong swimming abilities and excellent underwater vision.
Seals are carnivorous and feed mainly on fish, squid, crustaceans, and other marine animals. Their long whiskers, called vibrissae, are highly sensitive and allow them to detect vibrations and movements of prey in dark or murky water. Some species can dive to great depths and hold their breath for over an hour while hunting.
Many seal species are highly adapted to extreme environments, especially polar regions. Arctic and Antarctic seals rely on sea ice for breeding and resting, and some can maintain breathing holes in thick ice using their teeth. Their thick fur and blubber provide protection against freezing temperatures and icy waters.
Seals play an important role in marine ecosystems as both predators and prey. They help regulate fish populations and serve as a key food source for animals such as sharks, orcas, and polar bears. Changes in seal populations can significantly affect the balance of marine food webs.
Although some seal populations are stable or recovering, others face serious threats. Climate change, sea ice loss, pollution, fishing gear entanglement, and human disturbance all impact seal survival.
Types of Seals
Harbor Seal (Phoca vitulina)
Harbor seals are relatively small, with rounded heads and spotted gray or brown coats. They are known for hauling out on rocks, beaches, and ice floes. Harbor seals are highly adaptable and tolerate human presence better than many other seal species.
Found in: Coastal waters of the North Atlantic and North Pacific, including Canada, the United States, Europe, and Asia.
Gray Seal (Halichoerus grypus)
Gray seals are larger than harbor seals and have long, horse-like noses, especially in males. Their coats are mottled gray with dark patches. They are strong swimmers and can dive deeply to hunt fish.
Found in: North Atlantic Ocean, particularly around Canada, the northeastern United States, the UK, and northern Europe.
Ringed Seal (Pusa hispida)
Ringed seals are small, compact seals with distinctive light rings on their dark fur. They are closely associated with sea ice and are one of the most ice-dependent seal species. Ringed seals are also a primary prey species for polar bears.
Found in: Arctic regions of Canada, Greenland, Russia, and Alaska.
Hooded Seal (Cystophora cristata)
Hooded seals are best known for the inflatable nasal sac (“hood”) that adult males can expand to intimidate rivals. They have silvery-gray fur with dark patches and are capable of extremely deep dives.
Found in: Cold waters of the North Atlantic and Arctic Ocean.
Harp Seal (Pagophilus groenlandicus)
Harp seals are famous for their white-coated pups and the dark harp-shaped marking on the backs of adults. They are highly social and migrate long distances between feeding and breeding grounds.
Found in: North Atlantic and Arctic regions, especially around eastern Canada and Greenland.
Leopard Seal (Hydrurga leptonyx)
Leopard seals are large, powerful predators with long bodies, massive heads, and sharp teeth. Unlike most seals, they hunt penguins, seabirds, and even other seals. They are known for their aggressive hunting behavior.
Found in: Antarctic and sub-Antarctic waters.
Elephant Seal (Mirounga spp.)
Elephant seals are the largest of all seals, with males possessing an enlarged, trunk-like nose used for vocal displays. They can dive deeper and stay submerged longer than any other seal species.
Found in:
- Northern elephant seal: Pacific coast of North America
- Southern elephant seal: Southern Ocean and sub-Antarctic islands
Weddell Seal (Leptonychotes weddellii)
Weddell seals are known for their calm behavior and incredible diving abilities. They have robust bodies, short flippers, and often sing complex underwater vocalizations. They maintain breathing holes in thick ice using their teeth.
Found in: Coastal Antarctica, particularly around fast ice.
Monk Seal (Monachus & Neomonachus spp.)
Monk seals are among the rarest seals in the world. They have smooth, dark coats and prefer warm, tropical waters—unusual for seals. Monk seals are shy and often rest on remote beaches.
Found in:
- Mediterranean monk seal: Mediterranean Sea
- Hawaiian monk seal: Hawaiian Islands
(The Caribbean monk seal is extinct.)
Crabeater Seal (Lobodon carcinophaga)
Despite its name, the crabeater seal mainly feeds on krill, using its specially adapted, sieve-like teeth to filter food from the water. It is one of the most abundant large mammals on Earth.
Found in: Antarctic waters and pack ice surrounding the continent.
Ross Seal (Ommatophoca rossii)
Ross seals are rarely seen and poorly studied. They have large eyes, a small head, and are famous for producing complex, high-pitched underwater vocalizations.
Found in: Remote Antarctic pack ice regions.
Bearded Seal (Erignathus barbatus)
Bearded seals are named for their long, thick whiskers, which they use to detect prey on the seafloor. They are large, slow-moving seals that prefer shallow Arctic waters.
Found in: Arctic Ocean, including waters around Canada, Alaska, Russia, and Greenland.
Ribbon Seal (Histriophoca fasciata)
Ribbon seals are easily recognized by their striking black coats with bold white bands encircling the neck, forelimbs, and midsection. They are solitary and ice-dependent.
Found in: North Pacific Ocean, especially the Bering and Okhotsk Seas.
Spotted Seal (Phoca largha)
Spotted seals have light-colored coats covered in dark spots and are closely related to harbor seals. They rely heavily on sea ice for resting and breeding.
Found in: North Pacific and Arctic regions, including eastern Russia, Alaska, and northern Japan.
Caspian Seal (Pusa caspica)
The Caspian seal is one of the smallest seal species and one of the few found entirely in inland waters. It is endangered due to pollution and habitat loss.
Found in: Caspian Sea (bordered by Russia, Kazakhstan, Turkmenistan, Iran, and Azerbaijan).
Baikal Seal (Pusa sibirica)
Also called the nerpa, the Baikal seal is the only seal species that lives exclusively in freshwater. It has thick fur and a compact body adapted to cold conditions.
Found in: Lake Baikal, Siberia, Russia.
Southern Fur Seal (Arctocephalus spp.)
Southern fur seals are technically eared seals but are often grouped with seals in general discussions. They have dense underfur, long flippers, and are agile swimmers.
Found in: Southern Hemisphere coastal waters, including South America, southern Africa, Australia, and sub-Antarctic islands.
Northern Fur Seal (Callorhinus ursinus)
Northern fur seals are highly migratory and known for their thick fur and strong sexual dimorphism, with males much larger than females.
Found in: North Pacific Ocean, especially around the Bering Sea and Alaska.
Australian Fur Seal (Arctocephalus pusillus doriferus)
The Australian fur seal is the largest fur seal species. It has thick brown fur, a long snout, and strong flippers, making it agile both in water and on land.
Found in: Coastal waters and islands of southern Australia, especially Bass Strait.
Cape Fur Seal (Arctocephalus pusillus pusillus)
Cape fur seals are highly social and form massive breeding colonies. They have coarse outer fur, strong necks, and are excellent swimmers.
Found in: Southwestern and southern African coastlines, particularly Namibia and South Africa.
Subantarctic Fur Seal (Arctocephalus tropicalis)
This medium-sized fur seal has a pointed muzzle and dense underfur. It breeds on remote islands and spends much of its life at sea.
Found in: Subantarctic islands of the southern Indian and Atlantic Oceans.
Antarctic Fur Seal (Arctocephalus gazella)
Antarctic fur seals were once hunted nearly to extinction but have made a strong recovery. They are fast swimmers and feed mainly on krill and fish.
Found in: Antarctic and subantarctic waters, especially South Georgia and nearby islands.
South American Sea Lion (Otaria flavescens)
Often grouped with seals, this eared pinniped has visible external ears and a loud, barking call. Males have thick manes and aggressively defend territories.
Found in: Coastal South America along both the Atlantic and Pacific Oceans.
Steller Sea Lion (Eumetopias jubatus)
The largest sea lion species, Steller sea lions have massive heads, thick necks, and powerful bodies. They are vocal and often seen resting on rocky shores.
Found in: North Pacific Ocean, from Japan and Russia to Alaska and western Canada.