Cetacea: Meaning (information, definition, explanation, facts)

Cetaceans
Humpback Whale breeching
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Cetacea
Suborders
Mysticeti Odontoceti

The order Cetacea includes whales, dolphins and porpoises.

Cetus is Latin and is used in biological names to mean "whale"; its original meaning was more general, "large sea animal". It comes from Greek ketos, a sea monster.

Cetaceans are the mammals most fully adapted to aquatic life. Their body is fusiform (spindle-shaped). The forelimbs are modified into flippers. The tiny hindlimbs are vestigial, they do not attach to the backbone and are hidden within the body. The tail has horizontal flukes.

Cetaceans are nearly hairless, and are insulated by a thick layer of blubber.

Cetacea contains 10 families, and about 80 species.

Taxonomical listing

The specification shown here closely follows that of "Marine Mammals of the World. Systematics and Distribution", by Dale W. Rice (1998). Published by the Society of Marine Mammalogy as Special Publication No. 4, the tract has become the standard taxonomy reference in the field. See the Society's website (here) for further details. Differences reflect usage of common names and further discoveries since the publication of that work.

• ORDER CETACEA
  • Suborder Mysticeti: Baleen whales
    • Family Balaenidae: Right whales and Bowhead Whale
      • Genus Eubalaena
        • Atlantic Northern Right Whale, Eubalaena glacialis
        • Pacific Northern Right Whale, Eubalaena japonica
        • Southern Right Whale, Eubalaena australia
        • Bowhead Whale, Eubalaena mysticetus
    • Family Balaenopteridae: Rorquals
      • Subfamily Balaenopterinae
        • Genus Balaenoptera
          • Fin Whale, Balaenoptera physalus
          • Sei Whale, Balaenoptera borealis
          • Bryde's Whale, Balaenoptera brydei
          • Pygmy Bryde's Whale, (Eden's Whale) Balaenoptera edeni
          • Blue Whale, Balaenoptera musculus
          • Northern Minke Whale, Balaenoptera acutorostrata
          • Southern Minke Whale, (Antarctic Minke Whale) Balaenoptera bonaerensis
          • Balaenoptera omurai, discovery announced November 2003. No common name yet in usage
      • Subfamily Megapterinae
        • Genus Megaptera
          • Humpback Whale, Megaptera novaeangliae
    • † Genus Eobalaenoptera
      • † Eobalaenoptera harrisoni, fossil species first discovered June 2004. No common name.
    • Family Eschrichtiidae
      • Genus Eschrichtius
        • Gray Whale, Eschrichtius robustus
    • Family Neobalaenidae: Pygmy Right Whale
      • Genus Caperea
        • Pygmy Right Whale, Caperea marginata
  • Suborder Odontoceti: toothed whales
    • Superfamily Platanistoidea: River dolphins
      • Family Iniidae
        • Genus Inia
          • Amazon River Dolphin, Inia geoffrensis
      • Family Lipotidae
        • Genus Lipotes
          • Chinese River Dolphin, Lipotes vexillifer
      • Family Platanistidae
        • Genus Platanista
          • Ganges and Indus River Dolphin, Platanista gangetica
      • Family Pontoporiidae
        • Genus Pontoporia
          • La Plata Dolphin, Pontoporia blainvillei
    • Family Monodontidae
      • Genus Monodon
        • Narwhal, Monodon monocerus
      • Genus Delphinapterus
        • Beluga, Delphinapterus leucas
    • Family Phocoenidae: Porpoises
      • Genus Neophocaena
        • Finless Porpoise, Neophocaena phocaenoides
      • Genus Phocoena
        • Harbour Porpoise, Phocoena phocaena
        • Vaquita, Phocoena sinus
        • Spectacled Porpoise, Phocoena dioptrica
        • Burmeister's Porpoise, Phocoena spinipinnis
      • Genus Phocoenoides
        • Dall's Porpoise, Phocoenoides dalli
    • Family Physeteridae: Sperm Whale family
      • Genus Physeter
        • Sperm Whale, Physeter macrocephalus
    • Family Kogiidae
      • Genus Kogia
        • Dwarf Sperm Whale, Kogia sima
        • Pygmy Sperm Whale, Kogia breviceps
    • Family Ziphidae, Beaked whales
      • Genus Ziphius
        • Cuvier's Beaked Whale, Ziphius cavirostris
      • Genus Berardius
        • Arnoux's Beaked Whale, Berardius arnuxii
        • Baird's Beaked Whale (North Pacific Bottlenose Whale), Berardius bairdii
      • Genus Tasmacetus
        • Tasman Beaked Whale (Shepherd's Beaked Whale), Tasmacetus shepherdi
      • Subfamily Hyperoodontidae
        • Genus Indopacetus
          • Indo-Pacific Beaked Whale (Longman's Beaked Whale), Indopacetus pacificus
        • Genus Hyperoodon
          • Northern Bottlenose Whale, Hyperoodon ampullatus
          • Southern Bottlenose Whale, Hyperoodon planifrons
        • Genus Mesoplodon, Mesoplodont Whale
          • Hector's Beaked Whale, Mesoplodon hectori
          • True's Beaked Whale, Mesoplodon mirus
          • Gervais' Beaked Whale, Mesoplodon europaeus
          • Sowerby's Beaked Whale, Mesoplodon bidens
          • Gray's Beaked Whale, Mesoplodon grayi
          • Pygmy Beaked Whale, Mesoplodon peruvianus
          • Andrew's Beaked Whale, Mesoplodon bowdoini
          • Bahamonde's Beaked Whale, Mesoplodon bahamondi
          • Hubb's Beaked Whale, Mesoplodon carlhubbsi
          • Ginko-toothed Beaked Whale, Mesoplodon gingkgodens
          • Stejneger's Beaked Whale, Mesoplodon stejnegeri
          • Layard's Beaked Whale, Mesoplodon layardii
          • Blainville's Beaked Whale, Mesoplodon densirostris
    • Family Delphinidae: Dolphin
      • Genus Cephalorhynchus
        • Commerson's Dolphin, Cephalorhyncus commersonii
        • Chilean Dolphin, Cephalorhyncus eutropia
        • Heaviside's Dolphin, Cephalorhyncus heavisidii
        • Hector's Dolphin, Cephalorhyncus hectori
      • Genus Steno
        • Rough-toothed Dolphin, Steno bredanensis
      • Genus Sousa
        • Atlantic Humpback Dolphin, Sousa teuszi
        • Indian Humpback Dolphin, Sousa plumbea
        • Pacific Humpback Dolphin, Sousa chinensis
      • Genus Sotalia
        • Tucuxi, Sotalia fluviatilis
      • Genus Tursiops
        • Bottlenose Dolphin, Tursiops truncatus
        • Indian Ocean Bottlenose Dolphin, Tursiops aduncus
      • Genus Stenella
        • Pantropical Spotted Dolphin, Stenella attenuata
        • Atlantic Spotted Dolphin, Stenella frontalis
        • Spinner Dolphin, Stenella longirostris
        • Clymene Dolphin, Stenella clymene
        • Striped Dolphin, Stenella coeruleoalba
      • Genus Delphinus
        • Short-beaked Common Dolphin, Delphinus delphis
        • Long-beaked Common Dolphin, Delphinus capensis
        • (Arabian Common Dolphin, Delphinus tropicalis)
      • Genus Lagenodelphis
        • Fraser's Dolphin, Lagenodelphis hosei
      • Genus Lagenorhynchus
        • White-beaked Dolphin, Lagenorhynchus albirostris
        • Atlantic White-sided Dolphin, Lagenorhynchus acutus
        • Pacific White-sided Dolphin, Lagenorhynchus obliquidens
        • Dusky Dolphin, Lagenorhynchus obscurus
        • Black-chinned Dolphin, Lagenorhynchus australis
        • Hourglass Dolphin, Lagenorhynchus cruciger
      • Genus Lissodelphis
        • Northern Right Whale Dolphin, Lissodelphis borealis
        • Southern Right Whale Dolphin, Lissodelphis peronii
      • Genus Grampus
        • Risso's Dolphin, Grampus griseus
      • Genus Peponocephala
        • Melon-headed Whale, Peponocephala electra
      • Genus Feresa
        • Pygmy Killer Whale, Feresa attenuata
      • Genus Pseudorca
        • False Killer Whale, Pseudorca crassidens
      • Genus Orcinus
        • Orca, Orcinus orca
      • Genus Globicephala
        • Long-finned Pilot Whale, Globicephala melas
        • Short-finned Pilot Whale, Globicephala macrorhyncus
      • Genus Orcaella
        • Irrawaddy Dolphin, Orcaella brevirostris

The cetaceans are descendants of land-living mammals, most likely of the Artiodactyl order. They entered the water roughly 50 million years ago. See evolution of cetaceans for the details.