Seals, walruses, sea lions and fur seals are all marine animals known as pinnipeds. Pinniped is a Latin-derived word that can be translated to mean “feather-footed” or “fin-footed,” describing an important characteristic that distinguishes each species. Pinnipeds are divided into three distinct families that comprise 33 different species. Species in each family share some similarities but have variances in size, color, behavior and habitat.

Currently, seal populations around the world are stable. Sea lions, however, are more affected by threats from climate change, pollution and hunting. Three species of sea lions are listed as endangered by the IUCN.

A Family Affair

Pinnipeds are divided into three distinct families, Phocidae, Otariidae and Odobenidae. The family of Phocidae contains all of the true seals. True seals live in the cold ocean waters of the Arctic and off the coast of Antarctica. Harp, ringed, hooded, spotted, bearded and ribbon seals live in the Arctic. Crabeater, Weddell, leopard and Ross seals live in the Antarctic. Fur seals and sea lions comprise the Otariidae family. Fur seals and sea lions live in the Northern Pacific between Asia and North America and off the coasts of South America, Antarctica, southwestern Africa and southern Australia. The third and final family is Odobenidae, which exclusively groups the tusked walruses. All pinnipeds divide their time between near-shore terrestrial habitats and the ocean.

Leopard seal in Antarctica smiling and lounging on the ice

Leopard seal © Ted Martens

Some 50 million years ago, pinnipeds split off from other carnivores. These species adapted giant flippers, thick layers of blubber and long whiskers, enabling them to survive harsh life in the cold ocean waters. True seals are believed to be the modern relatives of a common terrestrial weasel-like ancestor, while the sea lion family group are the descendants of a terrestrial bear-like ancestor.

Seal vs. Sea Lion

True seals have various characteristics that separate the species from others in the Pinniped suborder. First off, seals have no external ears. While sea lions and fur seals have external ears, seals just have ear holes. Scientists use this major distinction to refer to species in the family Otariidae as eared seals and Phocidae as earless seals.

Seals in Antarctica © John Mittan-Mor

Sea lions and fur seals have long flippers and can rotate their back flippers under their bodies, allowing them to walk or even gallop across land. Sea lions are unique in that they have a reflective membrane at the back of the eye that acts as a mirror, bouncing what little light they find in the ocean back through the eye a second time, helping them see underwater.

A pair of Galápagos sea lions Diving and swimming playfully

A pair of Galapagos sea lions © Richard de Gouveia

Seals, on the other hand, have short flippers and can’t rotate their hind legs, so they are forced to flop around on their bellies when onshore, moving forward using caterpillar-like hitching movements. Both species spend time in water and on land. Seals, however, are more aqua dynamic than sea lions, making them better adapted to live in water. Their hind flippers angle backward and don’t rotate, making them faster while swimming but slower crawlers on land.

weddell seal Sleeping seal peaceful in snow and ice Antarctica

Weddell seal © Colby Brokvist

Aside from the yearly mating season, seals prefer to be solitary creatures, often living in caves in the arctic snow. Some seals never leave the ice pack, instead poking breathing holes in the ice to survive. Sea lions, however, live in large colonies called herds or rafts that can reach upwards of 1,500 individuals. Due to their social nature, sea lions and fur lions are much louder than true seals. Sea lions and fur seals communicate through loud barking or bellowing, while seals usually grunt softly to communicate.

Fur seal © Richard De Gouveia

Galapagos Fur Seals vs. Galapagos Sea Lions

Part of the Republic of Ecuador, the Galapagos Islands are distributed on either side of the equator in the Pacific Ocean, surrounding the center of the Western Hemisphere.

Eared seal, Galapagos sea lion

Sea lion © Richard de Gouveia

Galapagos fur seals are endemic to the islands, and they belong to a genus of fur seals called Arctocephalus (or Arctophoca), meaning bear-headed. Fur seals differ from sea lions because they have incredibly long hind flippers. Both the sea lion and the fur seal come from the same family, “Otariidae,” which means “eared seal.” The Galapagos sea lion belongs to the genus Zalophus which contains two extant sea lion species and previously contained the Japanese sea lion, which went extinct in the 1970s.

The Galapagos Islands are one of the rare places on Earth where humans can build close connections with sea lions and fur seals. On Nat Hab’s Galapagos Hiking & Kayaking Adventure, sea lion sightings while snorkeling and sailing are a daily occurrence. Nat Hab has gained paddling permits that grant access to exclusive enclaves most visitors never get to see. The current population of Galapagos sea lions is estimated to be up to 50,000, while the fur seal population is somewhere between 10,000-15,000, making the islands the ideal location to encounter these species in their natural habitat.

Woman traveler laughing and smiling gleefully surrounded by Galápagos sea lions basking in the sun

© Emily Supernavage