Cetacea
The order Cetacea (Template:IPAEng, L. cetus, whale) includes whales, dolphins and porpoises.
Cetus is Latin and is used in biological names to mean "whale"; its original meaning, "large sea animal," was more general. It comes from Ancient Greek  (ketos), meaning "whale" or "any huge fish or sea monster". Cetology is the branch of marine science associated with the study of cetaceans.
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.  As a group, they are noted for their high intelligence.
The order Cetacea contains ninety species, all marine except for five species of freshwater dolphins.  The order is divided into two suborders, Mysticeti (baleen whales) and Odontoceti (toothed whales, which includes dolphins and porpoises).

# Respiration, vision, hearing and echolocation
As mammals, cetaceans need to breathe air. Because of this, they need to come to the water's surface to exhale carbon dioxide and inhale a fresh supply of oxygen.  During diving, a muscular action closes the blowholes (nostrils), which remain closed until the cetacean next breaks the surface; when it surfaces, the muscles open the blowholes and warm air is exhaled.
Cetaceans' blowholes have evolved to a position on top of the head, allowing more time to expel stale air and inhale fresh air. When the stale air, warmed from the lungs, is exhaled, it condenses as it meets the cold air outside. As with a terrestrial mammal breathing out on a cold day, a small cloud of 'steam' appears. This is called the 'blow' or 'spout' and is different in terms of shape, angle and height, for each cetacean species. Cetaceans can be identified at a distance, using this characteristic, by experienced whalers or whale-watchers.
Cetaceans can go underwater for much longer periods of time than other mammals. Their duration under water varies greatly between speicies due to large physiological differences between many members of this Order. There are two studied advantages of cetacean physiology that let this Order (and other marine mammals) forage underwater for extended periods of time without breathing at the water surface.
Myoglobin concentrations in skeletal muscle of mammals have much variation. A New Zealand white rabbit has 0.08+/-0.06 g (in a 100 g Wet muscle) of myoglobin, whereas a Northern bottlenose whale has 6.34 g (in a 100 g Wet muscle) of myoglobin. Myoglobin, by nature, has a higher affinity to oxygen than haemoglobin. That is, myoglobin retains oxygen molecules better than hemoglobin. Therefore, it is useful to have higher concentrations of myoglobin when needed and there is no oxygen available for re-uptake. The higher the myoglobin concentration in cetacean skeletal muscle, the longer they can stay underwater and forage.
Increased body size is another way of elongating dive duration of large cetaceans. This is true because of two considered aspects. An increase in body size means that there is increase in muscle mass, therefore, increase in muscle oxygen stores. Another aspect is the universal correlation of mass and metabolic rate (Kleiber's law). In laymans terms Kleibers law states that the metabolic rate of a large animal is slower than a small animal per unit mass. From this we can conclude that larger animals will use up less oxygen than smaller animals (per mass unit).
The cetacean's eyes are set well back and to either side of its huge head. This means that cetaceans with pointed 'beaks' (such as dolphins) have good binocular vision forward and downward but others, with blunt heads (such as the Sperm Whale), can see either side but not directly ahead or directly behind. Tear glands secrete greasy tears, which protect the eyes from the salt in the water. Cetaceans also have an almost spherical lens in their eyes, which is most efficient at focusing what little light there is in the deep waters. Cetaceans make up for their generally quite poor vision (with the exception of the dolphin) with excellent hearing.
As with the eyes, the cetacean's ears are also small. Life in the sea accounts for the cetacean's loss of its external ears, whose function is to collect airborne sound waves and focus them in order for them to become strong enough to hear well. However, water is a better conductor of sound than air, so the external ear was no longer needed: It is no more than a tiny hole in the skin, just behind the eye. The inner ear, however, has become so well developed that the cetacean can not only hear sounds dozens of miles away, but it can also discern from which direction the sound comes.
Some cetaceans are capable of echolocation.  Many toothed whales emit clicks similar to those in echolocation, but it has not been demonstrated that they echolocate. Mysticeti have little need of echolocation, as they prey upon small fish that would be impractical to locate with echolocation. Some members of Odontoceti, such as dolphins and porpoises, do perform echolocation. These cetaceans use sound in the same way as bats - they emit a sound (called a click), which then bounces off an object and returns to them. From this, cetaceans can discern the size, shape, surface characteristics and movement of the object, as well as how far away it is. With this ability cetaceans can search for, chase and catch fast-swimming prey in total darkness. Echolocation is so advanced in most Odontoceti that they can distinguish between prey and non-prey (such as humans or boats); captive cetaceans can be trained to distinguish between, for example, balls of different sizes or shapes.
Cetaceans also use sound to communicate, whether it be groans, moans, whistles, clicks or the complex 'singing' of the Humpback Whale.

# Feeding
When it comes to food and feeding, cetaceans can be separated into two distinct groups. The toothed whales, Odontoceti like sperm whales, beluga whales, dolphins and porpoises, usually have lots of teeth that they use for catching fish, squid or other marine life. They do not chew their food, but swallow it whole. In the rare cases that they catch large prey, as when Orca (Orcinus orca) catch a seal, they tear chunks off it that in turn are swallowed whole.
The baleen whales or Mysticeti do not have teeth. Instead they have plates made of keratin (the same substance as human fingernails) which hang down from the upper jaw. These plates act like a giant filter, straining small animals (such as krill and fish) from the seawater. Cetaceans included in this group include the Blue Whale, the Humpback Whale, the Bowhead Whale and the Minke Whale.
Not all Mysticeti feed on plankton: the larger whales tend to eat small shoaling fish, such as herrings and sardine, called micronecton. One species of Mysticeti, the Gray Whale (Eschrichtius robustus), is a benthic feeder, primarily eating sea floor crustaceans.

# Mammalian nature
Cetaceans are mammals, that is, members of the class Mammalia. The closest living relative of cetaceans is the hippopotamus.
As mammals, cetaceans have characteristics that are common to all mammals: They are warm-blooded, breathe in air through their lungs, bear their young alive and suckle them on their own milk, and have hair, although very little of it.
Another way of discerning a cetacean from a fish is by the shape of the tail. The tail of a fish is vertical and moves from side to side when the fish swims. The tail of a cetacean  called a fluke  is horizontal and moves up and down, as cetaceans' spines bend in the same manner as a human spine.

# Taxonomic listing
The classification here closely follows Dale W. Rice, Marine Mammals of the World: Systematics and Distribution (1998), which has become the standard taxonomy reference in the field. There is very close agreement between this classification and that of Mammal Species of the World: 3rd Edition (Wilson and Reeder eds., 2005). Any differences are noted using the abbreviations "Rice" and "MSW3" respectively. Further differences due to recent discoveries are also noted.
Discussion of synonyms and subspecies are relegated to the relevant genus and species articles.
- ORDER CETACEA
Suborder Mysticeti: Baleen whales
Family Balaenidae: Right whales and Bowhead Whale
Genus Balaena
Bowhead Whale, Balaena mysticetus
Genus Eubalaena
North Atlantic Right Whale, Eubalaena glacialis
North Pacific Right Whale, Eubalaena japonica
Southern Right Whale, Eubalaena australis
Family Balaenopteridae: Rorquals
Subfamily Balaenopterinae
Genus Balaenoptera
Common Minke Whale, Balaenoptera acutorostrata
Antarctic Minke Whale, Balaenoptera bonaerensis
Sei Whale, Balaenoptera borealis
Bryde's Whale, Balaenoptera brydei
Eden's Whale Balaenoptera edeni - Rice lists this as a separate species, MSW3 does not
Balaenoptera omurai - MSW3 lists this is a synonym of Bryde's Whale but suggests this may be temporary.
Blue Whale, Balaenoptera musculus
Fin Whale, Balaenoptera physalus
Subfamily Megapterinae
Genus Megaptera
Humpback Whale, Megaptera novaeangliae
 Genus Eobalaenoptera
 Harrison's Whale, Eobalaenoptera harrisoni
Family Eschrichtiidae
Genus Eschrichtius
Gray Whale, Eschrichtius robustus
Family Neobalaenidae: Pygmy Right Whale
Genus Caperea
Pygmy Right Whale, Caperea marginata
Suborder Odontoceti: toothed whales
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 Delphinus
Long-beaked Common Dolphin, Delphinus capensis
Short-beaked Common Dolphin, Delphinus delphis
Arabian Common Dolphin, Delphinus tropicalis. Rice recognises this as a separate species. MSW3 does not.
Genus Feresa
Pygmy Killer Whale, Feresa attenuata
Genus Globicephala
Short-finned Pilot Whale, Globicephala macrorhyncus
Long-finned Pilot Whale, Globicephala melas
Genus Grampus
Risso's Dolphin, Grampus griseus
Genus Lagenodelphis
Fraser's Dolphin, Lagenodelphis hosei
Genus Lagenorhynchus
Atlantic White-sided Dolphin, Lagenorhynchus acutus
White-beaked Dolphin, Lagenorhynchus albirostris
Peale's Dolphin, Lagenorhynchus australis
Hourglass Dolphin, Lagenorhynchus cruciger
Pacific White-sided Dolphin, Lagenorhynchus obliquidens
Dusky Dolphin, Lagenorhynchus obscurus
Genus Lissodelphis
Northern Right Whale Dolphin, Lissodelphis borealis
Southern Right Whale Dolphin, Lissodelphis peronii
Genus Orcaella
Irrawaddy Dolphin, Orcaella brevirostris
Australian Snubfin Dolphin, Orcaella heinsohni. 2005 discovery, thus not recognized by Rice or MSW3 and subject to revision.
Genus Orcinus
Killer Whale, Orcinus orca
Genus Peponocephala
Melon-headed Whale, Peponocephala electra
Genus Pseudorca
False Killer Whale, Pseudorca crassidens
Genus Sotalia
Tucuxi, Sotalia fluviatilis, but see the species article for a discussion
Genus Sousa
Pacific Humpback Dolphin, Sousa chinensis
Indian Humpback Dolphin, Sousa plumbea
Atlantic Humpback Dolphin, Sousa teuszii
Genus Stenella
Pantropical Spotted Dolphin, Stenella attenuata
Clymene Dolphin, Stenella clymene
Striped Dolphin, Stenella coeruleoalba
Atlantic Spotted Dolphin, Stenella frontalis
Spinner Dolphin, Stenella longirostris
Genus Steno
Rough-toothed Dolphin, Steno bredanensis
Genus Tursiops - Rice and MSW3 tentatively agree on this classification but see species article for more detail.
Indian Ocean Bottlenose Dolphin, Tursiops aduncus
Common Bottlenose Dolphin,  Tursiops truncatus
Family Monodontidae
Genus Delphinapterus
Beluga, Delphinapterus leucas
Genus Monodon
Narwhal, Monodon monoceros
Family Phocoenidae: Porpoises
Genus Neophocaena
Finless Porpoise, Neophocaena phocaenoides
Genus Phocoena
Spectacled Porpoise, Phocoena dioptrica
Harbour Porpoise, Phocoena phocaena
Vaquita, Phocoena sinus
Burmeister's Porpoise, Phocoena spinipinnis
Genus Phocoenoides
Dall's Porpoise, Phocoenoides dalli
Family Physeteridae: Sperm Whale family
Genus Physeter
Sperm Whale, Physeter catodon (syn. P. macrocephalus)
Family Kogiidae - MSW3 treats Kogia as a member of Physeteridae
Genus Kogia
Pygmy Sperm Whale, Kogia breviceps
Dwarf Sperm Whale, Kogia sima
Superfamily Platanistoidea: River dolphins
Family Iniidae
Genus Inia
Amazon River Dolphin, Inia geoffrensis
Family Lipotidae - MSW3 treats Lipotes as a member of Iniidae
Genus Lipotes
 Baiji, Lipotes vexillifer
Family Pontoporiidae - MSW3 treats Pontoporia as a member of Iniidae
Genus Pontoporia
Franciscana, Pontoporia blainvillei
Family Platanistidae
Genus Platanista
Ganges and Indus River Dolphin, Platanista gangetica. MSW3 treats Platanista minor as a separate species, with common names Ganges River Dolphin and Indus River Dolphin, respectively.
Family Ziphidae, Beaked whales
Genus Berardius
Arnoux's Beaked Whale, Berardius arnuxii
Baird's Beaked Whale (North Pacific Bottlenose Whale), Berardius bairdii
Subfamily Hyperoodontidae
Genus Hyperoodon
Northern Bottlenose Whale, Hyperoodon ampullatus
Southern Bottlenose Whale, Hyperoodon planifrons
Genus Indopacetus
Indo-Pacific Beaked Whale (Longman's Beaked Whale), Indopacetus pacificus
Genus Mesoplodon, Mesoplodont Whale
Sowerby's Beaked Whale, Mesoplodon bidens
Andrews' Beaked Whale, Mesoplodon bowdoini
Hubbs' Beaked Whale, Mesoplodon carlhubbsi
Blainville's Beaked Whale, Mesoplodon densirostris
Gervais' Beaked Whale, Mesoplodon europaeus
Ginkgo-toothed Beaked Whale, Mesoplodon ginkgodens
Gray's Beaked Whale, Mesoplodon grayi
Hector's Beaked Whale, Mesoplodon hectori
Layard's Beaked Whale, Mesoplodon layardii
True's Beaked Whale, Mesoplodon mirus
Perrin's Beaked Whale, Mesoplodon perrini. This species was recognised in 2002 and as such is listed by MSW3 but not Rice.
Pygmy Beaked Whale, Mesoplodon peruvianus
Stejneger's Beaked Whale, Mesoplodon stejnegeri
Spade Toothed Whale, Mesoplodon traversii
Genus Tasmacetus
Tasman Beaked Whale (Shepherd's Beaked Whale), Tasmacetus shepherdi
Genus Ziphius
Cuvier's Beaked Whale, Ziphius cavirostris
- Suborder Mysticeti: Baleen whales
Family Balaenidae: Right whales and Bowhead Whale
Genus Balaena
Bowhead Whale, Balaena mysticetus
Genus Eubalaena
North Atlantic Right Whale, Eubalaena glacialis
North Pacific Right Whale, Eubalaena japonica
Southern Right Whale, Eubalaena australis
Family Balaenopteridae: Rorquals
Subfamily Balaenopterinae
Genus Balaenoptera
Common Minke Whale, Balaenoptera acutorostrata
Antarctic Minke Whale, Balaenoptera bonaerensis
Sei Whale, Balaenoptera borealis
Bryde's Whale, Balaenoptera brydei
Eden's Whale Balaenoptera edeni - Rice lists this as a separate species, MSW3 does not
Balaenoptera omurai - MSW3 lists this is a synonym of Bryde's Whale but suggests this may be temporary.
Blue Whale, Balaenoptera musculus
Fin Whale, Balaenoptera physalus
Subfamily Megapterinae
Genus Megaptera
Humpback Whale, Megaptera novaeangliae
 Genus Eobalaenoptera
 Harrison's Whale, Eobalaenoptera harrisoni
Family Eschrichtiidae
Genus Eschrichtius
Gray Whale, Eschrichtius robustus
Family Neobalaenidae: Pygmy Right Whale
Genus Caperea
Pygmy Right Whale, Caperea marginata
- Family Balaenidae: Right whales and Bowhead Whale
Genus Balaena
Bowhead Whale, Balaena mysticetus
Genus Eubalaena
North Atlantic Right Whale, Eubalaena glacialis
North Pacific Right Whale, Eubalaena japonica
Southern Right Whale, Eubalaena australis
- Genus Balaena
Bowhead Whale, Balaena mysticetus
- Bowhead Whale, Balaena mysticetus
- Genus Eubalaena
North Atlantic Right Whale, Eubalaena glacialis
North Pacific Right Whale, Eubalaena japonica
Southern Right Whale, Eubalaena australis
- North Atlantic Right Whale, Eubalaena glacialis
- North Pacific Right Whale, Eubalaena japonica
- Southern Right Whale, Eubalaena australis
- Family Balaenopteridae: Rorquals
Subfamily Balaenopterinae
Genus Balaenoptera
Common Minke Whale, Balaenoptera acutorostrata
Antarctic Minke Whale, Balaenoptera bonaerensis
Sei Whale, Balaenoptera borealis
Bryde's Whale, Balaenoptera brydei
Eden's Whale Balaenoptera edeni - Rice lists this as a separate species, MSW3 does not
Balaenoptera omurai - MSW3 lists this is a synonym of Bryde's Whale but suggests this may be temporary.
Blue Whale, Balaenoptera musculus
Fin Whale, Balaenoptera physalus
Subfamily Megapterinae
Genus Megaptera
Humpback Whale, Megaptera novaeangliae
- Subfamily Balaenopterinae
Genus Balaenoptera
Common Minke Whale, Balaenoptera acutorostrata
Antarctic Minke Whale, Balaenoptera bonaerensis
Sei Whale, Balaenoptera borealis
Bryde's Whale, Balaenoptera brydei
Eden's Whale Balaenoptera edeni - Rice lists this as a separate species, MSW3 does not
Balaenoptera omurai - MSW3 lists this is a synonym of Bryde's Whale but suggests this may be temporary.
Blue Whale, Balaenoptera musculus
Fin Whale, Balaenoptera physalus
- Genus Balaenoptera
Common Minke Whale, Balaenoptera acutorostrata
Antarctic Minke Whale, Balaenoptera bonaerensis
Sei Whale, Balaenoptera borealis
Bryde's Whale, Balaenoptera brydei
Eden's Whale Balaenoptera edeni - Rice lists this as a separate species, MSW3 does not
Balaenoptera omurai - MSW3 lists this is a synonym of Bryde's Whale but suggests this may be temporary.
Blue Whale, Balaenoptera musculus
Fin Whale, Balaenoptera physalus
- Common Minke Whale, Balaenoptera acutorostrata
- Antarctic Minke Whale, Balaenoptera bonaerensis
- Sei Whale, Balaenoptera borealis
- Bryde's Whale, Balaenoptera brydei
- Eden's Whale Balaenoptera edeni - Rice lists this as a separate species, MSW3 does not
- Balaenoptera omurai - MSW3 lists this is a synonym of Bryde's Whale but suggests this may be temporary.
- Blue Whale, Balaenoptera musculus
- Fin Whale, Balaenoptera physalus
- Subfamily Megapterinae
Genus Megaptera
Humpback Whale, Megaptera novaeangliae
- Genus Megaptera
Humpback Whale, Megaptera novaeangliae
- Humpback Whale, Megaptera novaeangliae
-  Genus Eobalaenoptera
 Harrison's Whale, Eobalaenoptera harrisoni
-  Harrison's Whale, Eobalaenoptera harrisoni
- Family Eschrichtiidae
Genus Eschrichtius
Gray Whale, Eschrichtius robustus
- Genus Eschrichtius
Gray Whale, Eschrichtius robustus
- Gray Whale, Eschrichtius robustus
- Family Neobalaenidae: Pygmy Right Whale
Genus Caperea
Pygmy Right Whale, Caperea marginata
- Genus Caperea
Pygmy Right Whale, Caperea marginata
- Pygmy Right Whale, Caperea marginata
- Suborder Odontoceti: toothed whales
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 Delphinus
Long-beaked Common Dolphin, Delphinus capensis
Short-beaked Common Dolphin, Delphinus delphis
Arabian Common Dolphin, Delphinus tropicalis. Rice recognises this as a separate species. MSW3 does not.
Genus Feresa
Pygmy Killer Whale, Feresa attenuata
Genus Globicephala
Short-finned Pilot Whale, Globicephala macrorhyncus
Long-finned Pilot Whale, Globicephala melas
Genus Grampus
Risso's Dolphin, Grampus griseus
Genus Lagenodelphis
Fraser's Dolphin, Lagenodelphis hosei
Genus Lagenorhynchus
Atlantic White-sided Dolphin, Lagenorhynchus acutus
White-beaked Dolphin, Lagenorhynchus albirostris
Peale's Dolphin, Lagenorhynchus australis
Hourglass Dolphin, Lagenorhynchus cruciger
Pacific White-sided Dolphin, Lagenorhynchus obliquidens
Dusky Dolphin, Lagenorhynchus obscurus
Genus Lissodelphis
Northern Right Whale Dolphin, Lissodelphis borealis
Southern Right Whale Dolphin, Lissodelphis peronii
Genus Orcaella
Irrawaddy Dolphin, Orcaella brevirostris
Australian Snubfin Dolphin, Orcaella heinsohni. 2005 discovery, thus not recognized by Rice or MSW3 and subject to revision.
Genus Orcinus
Killer Whale, Orcinus orca
Genus Peponocephala
Melon-headed Whale, Peponocephala electra
Genus Pseudorca
False Killer Whale, Pseudorca crassidens
Genus Sotalia
Tucuxi, Sotalia fluviatilis, but see the species article for a discussion
Genus Sousa
Pacific Humpback Dolphin, Sousa chinensis
Indian Humpback Dolphin, Sousa plumbea
Atlantic Humpback Dolphin, Sousa teuszii
Genus Stenella
Pantropical Spotted Dolphin, Stenella attenuata
Clymene Dolphin, Stenella clymene
Striped Dolphin, Stenella coeruleoalba
Atlantic Spotted Dolphin, Stenella frontalis
Spinner Dolphin, Stenella longirostris
Genus Steno
Rough-toothed Dolphin, Steno bredanensis
Genus Tursiops - Rice and MSW3 tentatively agree on this classification but see species article for more detail.
Indian Ocean Bottlenose Dolphin, Tursiops aduncus
Common Bottlenose Dolphin,  Tursiops truncatus
Family Monodontidae
Genus Delphinapterus
Beluga, Delphinapterus leucas
Genus Monodon
Narwhal, Monodon monoceros
Family Phocoenidae: Porpoises
Genus Neophocaena
Finless Porpoise, Neophocaena phocaenoides
Genus Phocoena
Spectacled Porpoise, Phocoena dioptrica
Harbour Porpoise, Phocoena phocaena
Vaquita, Phocoena sinus
Burmeister's Porpoise, Phocoena spinipinnis
Genus Phocoenoides
Dall's Porpoise, Phocoenoides dalli
Family Physeteridae: Sperm Whale family
Genus Physeter
Sperm Whale, Physeter catodon (syn. P. macrocephalus)
Family Kogiidae - MSW3 treats Kogia as a member of Physeteridae
Genus Kogia
Pygmy Sperm Whale, Kogia breviceps
Dwarf Sperm Whale, Kogia sima
Superfamily Platanistoidea: River dolphins
Family Iniidae
Genus Inia
Amazon River Dolphin, Inia geoffrensis
Family Lipotidae - MSW3 treats Lipotes as a member of Iniidae
Genus Lipotes
 Baiji, Lipotes vexillifer
Family Pontoporiidae - MSW3 treats Pontoporia as a member of Iniidae
Genus Pontoporia
Franciscana, Pontoporia blainvillei
Family Platanistidae
Genus Platanista
Ganges and Indus River Dolphin, Platanista gangetica. MSW3 treats Platanista minor as a separate species, with common names Ganges River Dolphin and Indus River Dolphin, respectively.
Family Ziphidae, Beaked whales
Genus Berardius
Arnoux's Beaked Whale, Berardius arnuxii
Baird's Beaked Whale (North Pacific Bottlenose Whale), Berardius bairdii
Subfamily Hyperoodontidae
Genus Hyperoodon
Northern Bottlenose Whale, Hyperoodon ampullatus
Southern Bottlenose Whale, Hyperoodon planifrons
Genus Indopacetus
Indo-Pacific Beaked Whale (Longman's Beaked Whale), Indopacetus pacificus
Genus Mesoplodon, Mesoplodont Whale
Sowerby's Beaked Whale, Mesoplodon bidens
Andrews' Beaked Whale, Mesoplodon bowdoini
Hubbs' Beaked Whale, Mesoplodon carlhubbsi
Blainville's Beaked Whale, Mesoplodon densirostris
Gervais' Beaked Whale, Mesoplodon europaeus
Ginkgo-toothed Beaked Whale, Mesoplodon ginkgodens
Gray's Beaked Whale, Mesoplodon grayi
Hector's Beaked Whale, Mesoplodon hectori
Layard's Beaked Whale, Mesoplodon layardii
True's Beaked Whale, Mesoplodon mirus
Perrin's Beaked Whale, Mesoplodon perrini. This species was recognised in 2002 and as such is listed by MSW3 but not Rice.
Pygmy Beaked Whale, Mesoplodon peruvianus
Stejneger's Beaked Whale, Mesoplodon stejnegeri
Spade Toothed Whale, Mesoplodon traversii
Genus Tasmacetus
Tasman Beaked Whale (Shepherd's Beaked Whale), Tasmacetus shepherdi
Genus Ziphius
Cuvier's Beaked Whale, Ziphius cavirostris
- 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 Delphinus
Long-beaked Common Dolphin, Delphinus capensis
Short-beaked Common Dolphin, Delphinus delphis
Arabian Common Dolphin, Delphinus tropicalis. Rice recognises this as a separate species. MSW3 does not.
Genus Feresa
Pygmy Killer Whale, Feresa attenuata
Genus Globicephala
Short-finned Pilot Whale, Globicephala macrorhyncus
Long-finned Pilot Whale, Globicephala melas
Genus Grampus
Risso's Dolphin, Grampus griseus
Genus Lagenodelphis
Fraser's Dolphin, Lagenodelphis hosei
Genus Lagenorhynchus
Atlantic White-sided Dolphin, Lagenorhynchus acutus
White-beaked Dolphin, Lagenorhynchus albirostris
Peale's Dolphin, Lagenorhynchus australis
Hourglass Dolphin, Lagenorhynchus cruciger
Pacific White-sided Dolphin, Lagenorhynchus obliquidens
Dusky Dolphin, Lagenorhynchus obscurus
Genus Lissodelphis
Northern Right Whale Dolphin, Lissodelphis borealis
Southern Right Whale Dolphin, Lissodelphis peronii
Genus Orcaella
Irrawaddy Dolphin, Orcaella brevirostris
Australian Snubfin Dolphin, Orcaella heinsohni. 2005 discovery, thus not recognized by Rice or MSW3 and subject to revision.
Genus Orcinus
Killer Whale, Orcinus orca
Genus Peponocephala
Melon-headed Whale, Peponocephala electra
Genus Pseudorca
False Killer Whale, Pseudorca crassidens
Genus Sotalia
Tucuxi, Sotalia fluviatilis, but see the species article for a discussion
Genus Sousa
Pacific Humpback Dolphin, Sousa chinensis
Indian Humpback Dolphin, Sousa plumbea
Atlantic Humpback Dolphin, Sousa teuszii
Genus Stenella
Pantropical Spotted Dolphin, Stenella attenuata
Clymene Dolphin, Stenella clymene
Striped Dolphin, Stenella coeruleoalba
Atlantic Spotted Dolphin, Stenella frontalis
Spinner Dolphin, Stenella longirostris
Genus Steno
Rough-toothed Dolphin, Steno bredanensis
Genus Tursiops - Rice and MSW3 tentatively agree on this classification but see species article for more detail.
Indian Ocean Bottlenose Dolphin, Tursiops aduncus
Common Bottlenose Dolphin,  Tursiops truncatus
- Genus Cephalorhynchus
Commerson's Dolphin, Cephalorhyncus commersonii
Chilean Dolphin, Cephalorhyncus eutropia
Heaviside's Dolphin, Cephalorhyncus heavisidii
Hector's Dolphin, Cephalorhyncus hectori
- Commerson's Dolphin, Cephalorhyncus commersonii
- Chilean Dolphin, Cephalorhyncus eutropia
- Heaviside's Dolphin, Cephalorhyncus heavisidii
- Hector's Dolphin, Cephalorhyncus hectori
- Genus Delphinus
Long-beaked Common Dolphin, Delphinus capensis
Short-beaked Common Dolphin, Delphinus delphis
Arabian Common Dolphin, Delphinus tropicalis. Rice recognises this as a separate species. MSW3 does not.
- Long-beaked Common Dolphin, Delphinus capensis
- Short-beaked Common Dolphin, Delphinus delphis
- Arabian Common Dolphin, Delphinus tropicalis. Rice recognises this as a separate species. MSW3 does not.
- Genus Feresa
Pygmy Killer Whale, Feresa attenuata
- Pygmy Killer Whale, Feresa attenuata
- Genus Globicephala
Short-finned Pilot Whale, Globicephala macrorhyncus
Long-finned Pilot Whale, Globicephala melas
- Short-finned Pilot Whale, Globicephala macrorhyncus
- Long-finned Pilot Whale, Globicephala melas
- Genus Grampus
Risso's Dolphin, Grampus griseus
- Risso's Dolphin, Grampus griseus
- Genus Lagenodelphis
Fraser's Dolphin, Lagenodelphis hosei
- Fraser's Dolphin, Lagenodelphis hosei
- Genus Lagenorhynchus
Atlantic White-sided Dolphin, Lagenorhynchus acutus
White-beaked Dolphin, Lagenorhynchus albirostris
Peale's Dolphin, Lagenorhynchus australis
Hourglass Dolphin, Lagenorhynchus cruciger
Pacific White-sided Dolphin, Lagenorhynchus obliquidens
Dusky Dolphin, Lagenorhynchus obscurus
- Atlantic White-sided Dolphin, Lagenorhynchus acutus
- White-beaked Dolphin, Lagenorhynchus albirostris
- Peale's Dolphin, Lagenorhynchus australis
- Hourglass Dolphin, Lagenorhynchus cruciger
- Pacific White-sided Dolphin, Lagenorhynchus obliquidens
- Dusky Dolphin, Lagenorhynchus obscurus
- Genus Lissodelphis
Northern Right Whale Dolphin, Lissodelphis borealis
Southern Right Whale Dolphin, Lissodelphis peronii
- Northern Right Whale Dolphin, Lissodelphis borealis
- Southern Right Whale Dolphin, Lissodelphis peronii
- Genus Orcaella
Irrawaddy Dolphin, Orcaella brevirostris
Australian Snubfin Dolphin, Orcaella heinsohni. 2005 discovery, thus not recognized by Rice or MSW3 and subject to revision.
- Irrawaddy Dolphin, Orcaella brevirostris
- Australian Snubfin Dolphin, Orcaella heinsohni. 2005 discovery, thus not recognized by Rice or MSW3 and subject to revision.
- Genus Orcinus
Killer Whale, Orcinus orca
- Killer Whale, Orcinus orca
- Genus Peponocephala
Melon-headed Whale, Peponocephala electra
- Melon-headed Whale, Peponocephala electra
- Genus Pseudorca
False Killer Whale, Pseudorca crassidens
- False Killer Whale, Pseudorca crassidens
- Genus Sotalia
Tucuxi, Sotalia fluviatilis, but see the species article for a discussion
- Tucuxi, Sotalia fluviatilis, but see the species article for a discussion
- Genus Sousa
Pacific Humpback Dolphin, Sousa chinensis
Indian Humpback Dolphin, Sousa plumbea
Atlantic Humpback Dolphin, Sousa teuszii
- Pacific Humpback Dolphin, Sousa chinensis
- Indian Humpback Dolphin, Sousa plumbea
- Atlantic Humpback Dolphin, Sousa teuszii
- Genus Stenella
Pantropical Spotted Dolphin, Stenella attenuata
Clymene Dolphin, Stenella clymene
Striped Dolphin, Stenella coeruleoalba
Atlantic Spotted Dolphin, Stenella frontalis
Spinner Dolphin, Stenella longirostris
- Pantropical Spotted Dolphin, Stenella attenuata
- Clymene Dolphin, Stenella clymene
- Striped Dolphin, Stenella coeruleoalba
- Atlantic Spotted Dolphin, Stenella frontalis
- Spinner Dolphin, Stenella longirostris
- Genus Steno
Rough-toothed Dolphin, Steno bredanensis
- Rough-toothed Dolphin, Steno bredanensis
- Genus Tursiops - Rice and MSW3 tentatively agree on this classification but see species article for more detail.
Indian Ocean Bottlenose Dolphin, Tursiops aduncus
Common Bottlenose Dolphin,  Tursiops truncatus
- Indian Ocean Bottlenose Dolphin, Tursiops aduncus
- Common Bottlenose Dolphin,  Tursiops truncatus
- Family Monodontidae
Genus Delphinapterus
Beluga, Delphinapterus leucas
Genus Monodon
Narwhal, Monodon monoceros
- Genus Delphinapterus
Beluga, Delphinapterus leucas
- Beluga, Delphinapterus leucas
- Genus Monodon
Narwhal, Monodon monoceros
- Narwhal, Monodon monoceros
- Family Phocoenidae: Porpoises
Genus Neophocaena
Finless Porpoise, Neophocaena phocaenoides
Genus Phocoena
Spectacled Porpoise, Phocoena dioptrica
Harbour Porpoise, Phocoena phocaena
Vaquita, Phocoena sinus
Burmeister's Porpoise, Phocoena spinipinnis
Genus Phocoenoides
Dall's Porpoise, Phocoenoides dalli
- Genus Neophocaena
Finless Porpoise, Neophocaena phocaenoides
- Finless Porpoise, Neophocaena phocaenoides
- Genus Phocoena
Spectacled Porpoise, Phocoena dioptrica
Harbour Porpoise, Phocoena phocaena
Vaquita, Phocoena sinus
Burmeister's Porpoise, Phocoena spinipinnis
- Spectacled Porpoise, Phocoena dioptrica
- Harbour Porpoise, Phocoena phocaena
- Vaquita, Phocoena sinus
- Burmeister's Porpoise, Phocoena spinipinnis
- Genus Phocoenoides
Dall's Porpoise, Phocoenoides dalli
- Dall's Porpoise, Phocoenoides dalli
- Family Physeteridae: Sperm Whale family
Genus Physeter
Sperm Whale, Physeter catodon (syn. P. macrocephalus)
- Genus Physeter
Sperm Whale, Physeter catodon (syn. P. macrocephalus)
- Sperm Whale, Physeter catodon (syn. P. macrocephalus)
- Family Kogiidae - MSW3 treats Kogia as a member of Physeteridae
Genus Kogia
Pygmy Sperm Whale, Kogia breviceps
Dwarf Sperm Whale, Kogia sima
- Genus Kogia
Pygmy Sperm Whale, Kogia breviceps
Dwarf Sperm Whale, Kogia sima
- Pygmy Sperm Whale, Kogia breviceps
- Dwarf Sperm Whale, Kogia sima
- Superfamily Platanistoidea: River dolphins
Family Iniidae
Genus Inia
Amazon River Dolphin, Inia geoffrensis
Family Lipotidae - MSW3 treats Lipotes as a member of Iniidae
Genus Lipotes
 Baiji, Lipotes vexillifer
Family Pontoporiidae - MSW3 treats Pontoporia as a member of Iniidae
Genus Pontoporia
Franciscana, Pontoporia blainvillei
Family Platanistidae
Genus Platanista
Ganges and Indus River Dolphin, Platanista gangetica. MSW3 treats Platanista minor as a separate species, with common names Ganges River Dolphin and Indus River Dolphin, respectively.
- Family Iniidae
Genus Inia
Amazon River Dolphin, Inia geoffrensis
- Genus Inia
Amazon River Dolphin, Inia geoffrensis
- Amazon River Dolphin, Inia geoffrensis
- Family Lipotidae - MSW3 treats Lipotes as a member of Iniidae
Genus Lipotes
 Baiji, Lipotes vexillifer
- Genus Lipotes
 Baiji, Lipotes vexillifer
-  Baiji, Lipotes vexillifer
- Family Pontoporiidae - MSW3 treats Pontoporia as a member of Iniidae
Genus Pontoporia
Franciscana, Pontoporia blainvillei
- Genus Pontoporia
Franciscana, Pontoporia blainvillei
- Franciscana, Pontoporia blainvillei
- Family Platanistidae
Genus Platanista
Ganges and Indus River Dolphin, Platanista gangetica. MSW3 treats Platanista minor as a separate species, with common names Ganges River Dolphin and Indus River Dolphin, respectively.
- Genus Platanista
Ganges and Indus River Dolphin, Platanista gangetica. MSW3 treats Platanista minor as a separate species, with common names Ganges River Dolphin and Indus River Dolphin, respectively.
- Ganges and Indus River Dolphin, Platanista gangetica. MSW3 treats Platanista minor as a separate species, with common names Ganges River Dolphin and Indus River Dolphin, respectively.
- Family Ziphidae, Beaked whales
Genus Berardius
Arnoux's Beaked Whale, Berardius arnuxii
Baird's Beaked Whale (North Pacific Bottlenose Whale), Berardius bairdii
Subfamily Hyperoodontidae
Genus Hyperoodon
Northern Bottlenose Whale, Hyperoodon ampullatus
Southern Bottlenose Whale, Hyperoodon planifrons
Genus Indopacetus
Indo-Pacific Beaked Whale (Longman's Beaked Whale), Indopacetus pacificus
Genus Mesoplodon, Mesoplodont Whale
Sowerby's Beaked Whale, Mesoplodon bidens
Andrews' Beaked Whale, Mesoplodon bowdoini
Hubbs' Beaked Whale, Mesoplodon carlhubbsi
Blainville's Beaked Whale, Mesoplodon densirostris
Gervais' Beaked Whale, Mesoplodon europaeus
Ginkgo-toothed Beaked Whale, Mesoplodon ginkgodens
Gray's Beaked Whale, Mesoplodon grayi
Hector's Beaked Whale, Mesoplodon hectori
Layard's Beaked Whale, Mesoplodon layardii
True's Beaked Whale, Mesoplodon mirus
Perrin's Beaked Whale, Mesoplodon perrini. This species was recognised in 2002 and as such is listed by MSW3 but not Rice.
Pygmy Beaked Whale, Mesoplodon peruvianus
Stejneger's Beaked Whale, Mesoplodon stejnegeri
Spade Toothed Whale, Mesoplodon traversii
Genus Tasmacetus
Tasman Beaked Whale (Shepherd's Beaked Whale), Tasmacetus shepherdi
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
- Arnoux's Beaked Whale, Berardius arnuxii
- Baird's Beaked Whale (North Pacific Bottlenose Whale), Berardius bairdii
- Subfamily Hyperoodontidae
Genus Hyperoodon
Northern Bottlenose Whale, Hyperoodon ampullatus
Southern Bottlenose Whale, Hyperoodon planifrons
Genus Indopacetus
Indo-Pacific Beaked Whale (Longman's Beaked Whale), Indopacetus pacificus
Genus Mesoplodon, Mesoplodont Whale
Sowerby's Beaked Whale, Mesoplodon bidens
Andrews' Beaked Whale, Mesoplodon bowdoini
Hubbs' Beaked Whale, Mesoplodon carlhubbsi
Blainville's Beaked Whale, Mesoplodon densirostris
Gervais' Beaked Whale, Mesoplodon europaeus
Ginkgo-toothed Beaked Whale, Mesoplodon ginkgodens
Gray's Beaked Whale, Mesoplodon grayi
Hector's Beaked Whale, Mesoplodon hectori
Layard's Beaked Whale, Mesoplodon layardii
True's Beaked Whale, Mesoplodon mirus
Perrin's Beaked Whale, Mesoplodon perrini. This species was recognised in 2002 and as such is listed by MSW3 but not Rice.
Pygmy Beaked Whale, Mesoplodon peruvianus
Stejneger's Beaked Whale, Mesoplodon stejnegeri
Spade Toothed Whale, Mesoplodon traversii
- Genus Hyperoodon
Northern Bottlenose Whale, Hyperoodon ampullatus
Southern Bottlenose Whale, Hyperoodon planifrons
- Northern Bottlenose Whale, Hyperoodon ampullatus
- Southern Bottlenose Whale, Hyperoodon planifrons
- Genus Indopacetus
Indo-Pacific Beaked Whale (Longman's Beaked Whale), Indopacetus pacificus
- Indo-Pacific Beaked Whale (Longman's Beaked Whale), Indopacetus pacificus
- Genus Mesoplodon, Mesoplodont Whale
Sowerby's Beaked Whale, Mesoplodon bidens
Andrews' Beaked Whale, Mesoplodon bowdoini
Hubbs' Beaked Whale, Mesoplodon carlhubbsi
Blainville's Beaked Whale, Mesoplodon densirostris
Gervais' Beaked Whale, Mesoplodon europaeus
Ginkgo-toothed Beaked Whale, Mesoplodon ginkgodens
Gray's Beaked Whale, Mesoplodon grayi
Hector's Beaked Whale, Mesoplodon hectori
Layard's Beaked Whale, Mesoplodon layardii
True's Beaked Whale, Mesoplodon mirus
Perrin's Beaked Whale, Mesoplodon perrini. This species was recognised in 2002 and as such is listed by MSW3 but not Rice.
Pygmy Beaked Whale, Mesoplodon peruvianus
Stejneger's Beaked Whale, Mesoplodon stejnegeri
Spade Toothed Whale, Mesoplodon traversii
- Sowerby's Beaked Whale, Mesoplodon bidens
- Andrews' Beaked Whale, Mesoplodon bowdoini
- Hubbs' Beaked Whale, Mesoplodon carlhubbsi
- Blainville's Beaked Whale, Mesoplodon densirostris
- Gervais' Beaked Whale, Mesoplodon europaeus
- Ginkgo-toothed Beaked Whale, Mesoplodon ginkgodens
- Gray's Beaked Whale, Mesoplodon grayi
- Hector's Beaked Whale, Mesoplodon hectori
- Layard's Beaked Whale, Mesoplodon layardii
- True's Beaked Whale, Mesoplodon mirus
- Perrin's Beaked Whale, Mesoplodon perrini. This species was recognised in 2002 and as such is listed by MSW3 but not Rice.
- Pygmy Beaked Whale, Mesoplodon peruvianus
- Stejneger's Beaked Whale, Mesoplodon stejnegeri
- Spade Toothed Whale, Mesoplodon traversii
- Genus Tasmacetus
Tasman Beaked Whale (Shepherd's Beaked Whale), Tasmacetus shepherdi
- Tasman Beaked Whale (Shepherd's Beaked Whale), Tasmacetus shepherdi
- Genus Ziphius
Cuvier's Beaked Whale, Ziphius cavirostris
- Cuvier's Beaked Whale, Ziphius cavirostris
Extinct