Sealife guideOcean giants: exploring the sea mammalsMarine vertebrates
Last updated on 10/16/2025 at 11:50 PM
Marine mammals include notably the cetaceans such as whales, dolphins, orcas and sperm whales, as well as pinnipeds like seals, walruses, sea lions and finally the sirenia which include manatees.
Marine mammals are characterized by a respiratory system made up of lungs. They therefore need to regularly surface to breathe.
Cetaceans
Cetaceans comprise more than 80 different species and are divided into two subgroups: the baleen whales, also called Mysticetes and the toothed whales, also called Odontocetes.
Baleen whales

Anatomy of baleen whales
Toothed whales
There are about thirty species of dolphins, all grouped within the family of Delphinidae.

Atlantic spotted dolphin
(Stenella frontalis)
(Stenella frontalis)

Atlantic white-sided dolphin
(Leucopleurus acutus)
(Leucopleurus acutus)

False killer whale
(Pseudorca crassidens)
(Pseudorca crassidens)

White headed dolphin
(Cephalorhynchus hectori)
(Cephalorhynchus hectori)
Pinnipeds
Mammals between land and sea
Pinnipeds include the well-known seals, sea lions and walruses, as well as the lesser-known sea lions and elephant seals. They are marine mammals perfectly adapted to aquatic life while maintaining a strong connection to land. Their name literally means « feathered feet », a reference to their limbs transformed into true flippers, which allow them to swim with remarkable agility. Under their skin, a thick layer of blubber protects them from the cold and serves as an energy reserve during long periods spent in icy waters.

Antarctic fur seal
(Arctocephalus gazella)
(Arctocephalus gazella)

Australian sea lion
(Neophoca cinerea)
(Neophoca cinerea)

Harbor seal
(Phoca vitulina)
(Phoca vitulina)
Champions of adaptation
Whether resting on the ice floes, diving hundreds of meters deep, or moving gracefully among the waves, pinnipeds are true champions of adaptation. Sea lions use their front flippers to move on land, while seals, less agile on land, excel in diving. The walrus, with its massive ivory tusks, stands out for its Arctic lifestyle and shellfish-based diet. These animals, both powerful and graceful, perfectly illustrate the successful transition between terrestrial and marine life.
Discover sea mammals

Amazon river dolphin
(Inia geoffrensis)
(Inia geoffrensis)

Antarctic fur seal
(Arctocephalus gazella)
(Arctocephalus gazella)

Atlantic white-sided dolphin
(Leucopleurus acutus)
(Leucopleurus acutus)

Commerson's dolphin
(Cephalorhynchus commersonii)
(Cephalorhynchus commersonii)

Common bottlenose dolphin
(Tursiops truncatus)
(Tursiops truncatus)

Florida manatee
(Trichechus manatus latirostris)
(Trichechus manatus latirostris)

Gray whale
(Eschrichtius robustus)
(Eschrichtius robustus)

Striped dolphin
(Stenella coeruleoalba)
(Stenella coeruleoalba)
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Poisson lézard, anoli
(Synodus intermedius)
(Synodus intermedius)
