The order

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 Cetacea (icon) includes the marine mammals commonly known as whale

Whale

Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

s, dolphin

Dolphin

Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

s, and porpoise

Porpoise

Porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen...

s. Cetus is Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

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

Ancient Greek

Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

  (), meaning "whale" or "any huge fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 or sea monster

Sea monster

Sea monsters are sea-dwelling mythical or legendary creatures, often believed to be of immense size.Marine monsters can take many forms, including sea dragons, sea serpents, or multi-armed beasts. They can be slimy or scaly and are often pictured threatening ships or spouting jets of water...

". In Greek mythology

Greek mythology

Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...

 the monster Perseus

Perseus

Perseus ,Perseos and Perseas are not used in English. the legendary founder of Mycenae and of the Perseid dynasty of Danaans there, was the first of the mythic heroes of Greek mythology whose exploits in defeating various archaic monsters provided the founding myths of the Twelve Olympians...

 defeated was called Ceto

Ceto

In ancient Greek, the word ketos - Latinized as cetus - denotes a large fish, a whale, a shark, or a sea monster. The sea monsters slain by Perseus and Heracles were each referred to as a cetus by ancient sources. The term cetacean originates from cetus. In Greek art, cetea were depicted as...

, which is depicted by the constellation

Constellation

In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

 of Cetus

Cetus

Cetus is a constellation. Its name refers to Cetus, a sea monster in Greek mythology, although it is often called 'the whale' today. Cetus is located in the region of the sky that contains other water-related constellations such as Aquarius, Pisces, and Eridanus.-Ecliptic:Although Cetus is not...

. Cetology

Cetology

Cetology is the branch of marine mammal science that studies the approximately eighty species of whales, dolphins, and porpoise in the scientific order Cetacea...

 is the branch of marine science associated with the study of cetaceans.

Cetaceans are the mammal

Mammal

Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s best adapted to aquatic life

Aquatic adaptation

Several animal groups have undergone aquatic adaptation, going from being purely terrestrial animals to living at least part of the time in water. The adaptations in early speciation tend to develop as the animal ventures into water in order to find available food. As successive generations spend...

. 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 from the cooler water they inhabit by a thick layer of blubber

Blubber

Blubber is a thick layer of vascularized adipose tissue found under the skin of all cetaceans, pinnipeds and sirenians.-Description:Lipid-rich, collagen fiber–laced blubber comprises the hypodermis and covers the whole body, except for parts of the appendages, strongly attached to the musculature...

. Some species are noted for their high intelligence

Cetacean intelligence

Cetacean intelligence denotes the cognitive capabilities of the Cetacea order of mammals, which includes whales, porpoises, and dolphins.-Brain size:...

.

Respiration

Cetaceans breathe air. They surface periodically to exhale carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 and inhale a fresh supply of oxygen

Oxygen

Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

. During diving, a muscular action closes the blowholes

Blowhole (biology)

In biology, a blowhole is the hole at the top of a cetacean's head through which the animal breathes air. It is homologous with the nostril of other mammals. As whales reach the water surface to breathe, they will forcefully expel air through the blowhole. Not only is air expelled, but mucus and...

 (nostril

Nostril

A nostril is one of the two channels of the nose, from the point where they bifurcate to the external opening. In birds and mammals, they contain branched bones or cartilages called turbinates, whose function is to warm air on inhalation and remove moisture on exhalation...

s), 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

Evolution of cetaceans

The cetaceans are marine mammal descendants of land mammals. Their terrestrial origins are indicated by:* Their need to breathe air from the surface;* The bones of their fins, which resemble the limbs of land mammals...

 to a position at the top of the head, simplifying breathing in sometimes rough seas. When the stale air, warmed from the lungs, is exhaled, it condenses as it meets colder external air. 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 varies by species in terms of shape, angle and height. Species can be identified at a distance using this characteristic.

Cetaceans can remain under water for much longer periods than most other mammals, (approximately 7–30 minutes, varying by species) due to large physiological differences. Two studied advantages of cetacean physiology let this order (and other marine mammals) forage underwater for extended periods without breathing:

• Mammalian myoglobin
  Myoglobin
  Myoglobin is an iron- and oxygen-binding protein found in the muscle tissue of vertebrates in general and in almost all mammals. It is related to hemoglobin, which is the iron- and oxygen-binding protein in blood, specifically in the red blood cells. The only time myoglobin is found in the...
  
   concentrations in skeletal
  Skeleton
  The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
  
   muscle
  Muscle
  Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
  
   have much variation. New Zealand
  New Zealand
  New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
  
   white rabbits have 0.08 gram (0.00282191696840896 oz) +/- 0.6 gram (0.0211643772630672 oz) myoglobin in 100 grams (3.5 oz) of wet muscle, whereas a northern bottlenose whale has 6.34 gram (0.22363691974641 oz). Myoglobin, by nature, has a higher oxygen affinity than hemoglobin
  Hemoglobin
  Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...
  
  . The higher the myoglobin concentration in skeletal muscle, the longer the animal can stay underwater.

• Increased body size also increases maximum dive duration. Greater body size implies increased muscle mass and increased oxygen stores. Cetaceans also obey Kleiber's law
  Kleiber's law
  Kleiber's law, named after Max Kleiber's biological work in the early 1930s, is the observation that, for the vast majority of animals, an animal's metabolic rate scales to the ¾ power of the animal's mass. Symbolically: if q0 is the animal's metabolic rate, and M the animal's mass, then Kleiber's...
  
  , which states that mass and metabolic rate are inversely related. I.e., larger animals consume less oxygen than smaller animals per unit mass.

Vision, hearing and echolocation

Cetacean eyes are set on the side rather than the front of the head. This means that only cetaceans with pointed 'beaks' (such as dolphins) have good binocular vision forward and downward. Tear glands secrete greasy tears, which protect the eyes from the salt in the water. The lens is almost spherical, which is most efficient at focusing the minimal light that reaches deep water. Cetaceans make up for their generally poor vision (with the exception of the dolphin) with excellent hearing.

As with the eyes, cetacean ears

EARS

EARS may refer to:* Electoral software* Electronic Arts, Redwood Shores campus.* Emirates Amateur Radio Society...

 are also small. Life in the sea accounts for the cetacean's loss of its external ears, whose function is to collect and focus airborne sound waves. However, water conducts sound better than air, so the external ear is unneeded: it is a tiny hole in the skin, just behind the eye. The highly developed inner ear can detect sounds from dozens of miles away and discern from which direction the sound comes.

Odontoceti are generally capable of echolocation

Animal echolocation

Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects...

. From this, Odontoceti can discern the size, shape, surface characteristics, distance and movement of an object. 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 Odontoceti can be trained to distinguish between, for example, balls of different sizes or shapes. Mysticeti have exceptionally thin, wide basilar membranes in their cochleae without stiffening agents - making their ears adapted for processing low to infrasonic frequencies.

Cetaceans also use sound to communicate

Communication

Communication is the activity of conveying meaningful information. Communication requires a sender, a message, and an intended recipient, although the receiver need not be present or aware of the sender's intent to communicate at the time of communication; thus communication can occur across vast...

, whether it be groans, moans, whistles, clicks or the complex 'singing' of the humpback whale

Humpback Whale

The humpback whale is a species of baleen whale. One of the larger rorqual species, adults range in length from and weigh approximately . The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the...

.

Besides hearing and vision, at least one species, the Tucuxi

Tucuxi

The Tucuxi , alternately bufeo gris or bufeo negro is a dolphin found in the rivers of the Amazon Basin. The word "tucuxi" is derived from the Tupi language word tuchuchi-ana and has now been adopted as the species' common name...

 or Guiana Dolphin, is able to use electroreception to sense prey.

Feeding

The toothed whales such as the sperm whale, beluga, dolphins and porpoises, have teeth that they use for catching fish

Fish

Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

, squid

Squid

Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...

 or other marine life. They do not chew but swallow prey whole. When they catch large prey, such as when the orca

Orca

The killer whale , commonly referred to as the orca, and less commonly as the blackfish, is a toothed whale belonging to the oceanic dolphin family. Killer whales are found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas...

 (Orcinus orca) catches a seal

Pinniped

Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...

, they bite off and swallow one chunk at a time.

Mysticeti instead have baleen

Baleen

Baleen or whalebone is a filter-feeder system inside the mouths of baleen whales. The baleen system works when a whale opens its mouth underwater and then water pours into the whale's mouth. The whale then pushes the water out, and animals such as krill are filtered by the baleen and remain as food...

 plates made of keratin

Keratin

Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...

 (the same substance as human fingernails) which hang from the upper jaw. These plates filter small animals (such as krill

Krill

Krill is the common name given to the order Euphausiacea of shrimp-like marine crustaceans. Also known as euphausiids, these small invertebrates are found in all oceans of the world...

 and fish) from the seawater. Cetaceans included in this group include the Blue, Humpback, Bowhead and Minke whales.

Not all Mysticeti feed on plankton

Plankton

Plankton are any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. That is, plankton are defined by their ecological niche rather than phylogenetic or taxonomic classification...

: the larger species eat small shoaling fish, such as herring

Herring

Herring is an oily fish of the genus Clupea, found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Three species of Clupea are recognized. The main taxa, the Atlantic herring and the Pacific herring may each be divided into subspecies...

 and sardine

Sardine

Sardines, or pilchards, are several types of small, oily fish related to herrings, family Clupeidae. Sardines are named after the Mediterranean island of Sardinia, around which they were once abundant....

, called micronecton. The gray whale

Gray Whale

The gray whale, Eschrichtius robustus, is a baleen whale that migrates between feeding and breeding grounds yearly. It reaches a length of about , a weight of , and lives 50–70 years. The common name of the whale comes from the gray patches and white mottling on its dark skin. Gray whales were...

 (Eschrichtius robustus), is a benthic

Benthos

Benthos is the community of organisms which live on, in, or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.Many organisms...

 feeder, primarily eating sea floor crustacean

Crustacean

Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s.

Mammalian nature

Cetaceans are mammals, that is, members of the class

Class (biology)

In biological classification, class is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, order, family, genus, and species, with class fitting between phylum and order...

 Mammalia. Their closest living relatives are the even-toed ungulate

Even-toed ungulate

The even-toed ungulates are ungulates whose weight is borne about equally by the third and fourth toes, rather than mostly or entirely by the third as in odd-toed ungulates such as horses....

s, such as the hippopotamus

Hippopotamus

The hippopotamus , or hippo, from the ancient Greek for "river horse" , is a large, mostly herbivorous mammal in sub-Saharan Africa, and one of only two extant species in the family Hippopotamidae After the elephant and rhinoceros, the hippopotamus is the third largest land mammal and the heaviest...

 and deer

Deer

Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...

.
Mammalian characteristics include warm-blooded

Warm-blooded

The term warm-blooded is a colloquial term to describe animal species which have a relatively higher blood temperature, and maintain thermal homeostasis primarily through internal metabolic processes...

ness, breathing air through their lungs, and suckling

Breastfeeding

Breastfeeding is the feeding of an infant or young child with breast milk directly from female human breasts rather than from a baby bottle or other container. Babies have a sucking reflex that enables them to suck and swallow milk. It is recommended that mothers breastfeed for six months or...

 their young, and growing hair

Hair

Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....

, although very little of it.

Another way of distinguishing a cetacean from a fish is the shape of the tail. Fish tails are vertical and move from side to side when the fish swims. Cetacea tails—called a fluke—are horizontal and move up and down, because cetacea spines bend in the same manner as a human

Human

Humans are the only living species in the Homo genus...

 spine.

Taxonomy

The order Cetacea contains about 90 species, all marine except for 4 species of freshwater dolphins

River dolphin

River dolphins are the four living species of dolphin that reside in freshwater rivers and estuaries. River dolphins inhabit areas of Asia and South America. They are classed in the Platanistoidea superfamily of cetaceans. Three species live in fresh water rivers. The fourth species, the La Plata...

. The order contains two suborders, Mysticeti  (baleen whales) and Odontoceti (toothed whales, which includes dolphins and porpoises). The species range in size from Commerson's dolphin

Commerson's Dolphin

Commerson's Dolphin is one of four dolphins in the Cephalorhynchus genus. The species has also the common names Skunk Dolphin, Piebald Dolphin and Panda Dolphin...

, smaller than a human, to the Blue Whale

Blue Whale

The blue whale is a marine mammal belonging to the suborder of baleen whales . At in length and or more in weight, it is the largest known animal to have ever existed....

, the largest animal ever known to have lived.

Evolution

The cetaceans (whale

Whale

Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

s, dolphin

Dolphin

Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

s and porpoise

Porpoise

Porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen...

s) are marine mammal

Marine mammal

Marine mammals, which include seals, whales, dolphins, and walruses, form a diverse group of 128 species that rely on the ocean for their existence. They do not represent a distinct biological grouping, but rather are unified by their reliance on the marine environment for feeding. The level of...

 descendants of the artiodactyl family Raoellidae, a group of land mammals characterized by an even-toed ungulate skull, slim limbs, and an ear with significant similarities to that of early whales. The terrestrial origins of cetaceans are indicated by their need to breathe air from the surface or the bones of their fins, which resemble the limbs of land mammals, including the vestigial remains of hind legs inherited from the four-legged ancestors.

The question of how land animals evolved into ocean-going leviathan

Leviathan

Leviathan , is a sea monster referred to in the Bible. In Demonology, Leviathan is one of the seven princes of Hell and its gatekeeper . The word has become synonymous with any large sea monster or creature...

s was a mystery until discoveries starting in the late 1970s in Pakistan

Pakistan

Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...

 revealed several stages in the transition of cetaceans from land to sea:

Pakicetus Pakicetus Pakicetus is a genus of extinct terrestrial carnivorous mammal of the family Pakicetidae which was endemic to Pakistan from the Eocene .Pakicetus existed for approximately...	Ambulocetus Ambulocetus Ambulocetus was an early cetacean that could walk as well as swim. It lived during early Eocene some 50-49 million years ago. It is a transitional fossil that shows how whales evolved from land-living mammals. The Ambulocetus fossils were found in Pakistan by anthropologist Johannes Thewissen...	Kutchicetus Kutchicetus Kutchicetus is an extinct genus of early carnivorous freshwater whales of the family Remingtonocetidae endemic to the coastline of the ancient Tethys Ocean during the Eocene living from 55.8—40.4 mya, existing for approximately .-Taxonomy:...	Protocetus Protocetus Protocetus atavus is an extinct species of primitive cetacean from Egypt. It lived during the middle Eocene period 45 million years ago....	Janjucetus Janjucetus Janjucetus is an extinct genus of whale, and a basal form of the Mysticeti, a clade which includes the extant baleen whales. The only known species, Janjucetus hunderi, lived during the late Oligocene, about 25 million years ago in coastal seas off southeast Australia. Unlike modern mysticetes, it...	Squalodon Squalodon Squalodon is an extinct genus of whales, belonging to the family Squalodontidae. Named by Grateloup in 1840, it was originally believed to be an iguanodontid dinosaur but has since been reclassified. The name Squalodon comes from Squalus, a genus of shark...

This series of images does not capture the true phylogenetic evolution

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

 of a particular species, but they are illustrative representation of the evolution of cetaceans from terrestrial four-legged mammals, from their probable ancestor, through different stages of adaptation to aquatic life to modern cetaceans type; aerodynamic body shape, fully developed caudal fin and vestigial hind legs. The separation of cetaceans in suborder baleen whales and suborder toothed whales, occurred during the Oligocene

Oligocene

The Oligocene is a geologic epoch of the Paleogene Period and extends from about 34 million to 23 million years before the present . As with other older geologic periods, the rock beds that define the period are well identified but the exact dates of the start and end of the period are slightly...

 (Janjucetus and Squalodon represent the early forms of their suborders).

Mysticeti vs Odontoceti

Fossils indicate that before evolving baleen, Mysticeti also had teeth, so defining the Odontoceti via teeth alone is problematic. Instead, paleontologists have identified other features uniting fossil and modern odontocetes that are not shared by Mysticetes. It was also assumed that toothed whales evolved their assymetrical skulls as an adaptation to their echolocation, but newer discoveries indicate that the common ancestor of the present whales actually had a contorted skull as well. Cranial asymmetry is now known to have evolved in ancient whales as part of a set of traits linked to directional hearing, including pan-bone thinning of the lower jaws, the development of mandibular fat pads, and the isolation of the ear region . This likely means that while the asymmetry in the Odontoceti skull has increased over time, the Mysticeti skull has evolved from asymmetrical to a symmetrical.

Characteristic	Odontoceti	Mysticeti
Feeding	Echolocation Animal echolocation Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects... , fast	Filter feeder, not fast
Size	|Smaller (except Sperm whale Sperm Whale The sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...  and Beaked Whale Beaked whale Beaked whales are 21 species of toothed whales, members of the family Ziphiidae, are notable for their elongated beaks. Beaked whales are one of the world's most extreme divers. They can dive for long periods—20 to 30 minutes is common, and 85 minute dives have been recorded—and to... )	Larger (except pygmy right whale Pygmy Right Whale The pygmy right whale is a baleen whale, the sole member of the family Neobalaenidae. First described by John Edward Gray in 1846, it is the smallest of the baleen whales, ranging between and in length and 3,000 and 3,500 kg in mass... )
Blowhole	One	Two
Dentition Dentition Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, the characteristic arrangement, kind, and number of teeth in a given species at a given age...	|Teeth	Baleen Baleen Baleen or whalebone is a filter-feeder system inside the mouths of baleen whales. The baleen system works when a whale opens its mouth underwater and then water pours into the whale's mouth. The whale then pushes the water out, and animals such as krill are filtered by the baleen and remain as food...  plates
Melon Melon (whale) The melon is an ovoid-shaped, fatty organ found in the forehead of all toothed whales , including dolphins and porpoises and believed to be used in echolocation....	Ovoid, in anterior facial region	Vestigial or none
Skull Skull The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...  and facial tissue	Dorsally asymmetric	|Symmetric
Sexual dimorphism Sexual dimorphism Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...	Some species have larger males	Females always larger
Mandible Mandible The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...	Symphyseal (fused anteriorly)	Nonsymphyseal
Pan bone of lower jaw	Yes	No
Maxillae projection	Outward over expanded supraorbital processes	Under eye orbit, with bony protuberance anterior to eye orbit
Olfactory nerve Olfactory nerve The olfactory nerve, or cranial nerve I, is the first of twelve cranial nerves. It is instrumental in the sense of smell. Derived from the embryonic nasal placode, the olfactory nerve is capable of regeneration.-Anatomy:...  and bulb Olfactory bulb The olfactory bulb is a structure of the vertebrate forebrain involved in olfaction, the perception of odors.-Anatomy:In most vertebrates, the olfactory bulb is the most rostral part of the brain. In humans, however, the olfactory bulb is on the inferior side of the brain...	Absent	Vestigal
Periotic bone Periotic bone Periotic bone is the single bone that surrounds the ear of mammals. It is formed from the fusion of the pro-otic, epiotic, and opisthotic bones.- External links :* http://www.encyclopedia.com/doc/1O8-perioticbone.html...	External to skull Skull The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates... , fused with tympanic bulla	Fused with skull Skull The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...

Classification

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
      Balaenidae
      Balaenidae is a family of mysticete whales that contains two living genera. Commonly called the right whales as it contains mainly right whale species...
      
      : Right whale
      Right whale
      Right whales are three species of large baleen whales consisting of two genera in the family Balaenidae of order Cetacea. Their bodies are very dark gray or black and rotund....
      
      s and bowhead whale
      Bowhead Whale
      The bowhead whale is a baleen whale of the right whale family Balaenidae in suborder Mysticeti. A stocky dark-colored whale without a dorsal fin, it can grow to in length. This thick-bodied species can weigh to , second only to the blue whale, although the bowhead's maximum length is less than...
      
      
      • Genus Balaena
        Balaena
        Balaena is a genus of cetacean in the Balaenidae family. This family is also known as the Right Whales, which can cause confusion as there is also a species of whale called the Right Whale. The only extant species is the Bowhead whale. The fossil record of Balaena, dating to the late Miocene,...
        
        
        • Bowhead whale
          Bowhead Whale
          The bowhead whale is a baleen whale of the right whale family Balaenidae in suborder Mysticeti. A stocky dark-colored whale without a dorsal fin, it can grow to in length. This thick-bodied species can weigh to , second only to the blue whale, although the bowhead's maximum length is less than...
          
          , Balaena mysticetus
      • Genus Eubalaena
        • North Atlantic right whale
          North Atlantic Right Whale
          The North Atlantic right whale which means "good, or true, whale of the ice") is a baleen whale, one of three right whale species belonging to the genus Eubalaena, formerly classified as a single species. With only 400 in existence, North Atlantic right whales are among the most endangered whales...
          
          , Eubalaena glacialis
        • North Pacific right whale
          North Pacific Right Whale
          The North Pacific right whale is a very large, robust baleen whale species that is now extremely rare and endangered. The Northeast Pacific subpopulation, that summers in the southeastern Bering Sea and Gulf of Alaska, may have no more than 50 animals...
          
          , Eubalaena japonica
        • Southern right whale
          Southern Right Whale
          The southern right whale is a baleen whale, one of three species classified as right whales belonging to the genus Eubalaena. Like other right whales, the southern right whale is readily distinguished from others by the callosities on its head, a broad back without a dorsal fin, and a long arching...
          
          , Eubalaena australis
    • Family Balaenopteridae: Rorquals
      • Subfamily Balaenopterinae
        • Genus Balaenoptera
          Balaenoptera
          Balaenoptera is a genus of Balaenopteridae, the Rorqual whales, and contains eight species. The species Balaenoptera omurai was published in 2003...
          
          
          • Common minke whale
            Common Minke Whale
            The common minke whale or northern minke whale, , is a species of minke whale within the suborder of baleen whales.-Taxonomy:...
            
            , Balaenoptera acutorostrata
          • Antarctic minke whale
            Antarctic Minke Whale
            The Antarctic minke whale or southern minke whale , is a species of minke whale within the suborder of baleen whales.-Taxonomy:...
            
            , Balaenoptera bonaerensis
          • Sei whale
            Sei Whale
            The sei whale , Balaenoptera borealis, is a baleen whale, the third-largest rorqual after the blue whale and the fin whale. It inhabits most oceans and adjoining seas, and prefers deep offshore waters. It avoids polar and tropical waters and semi-enclosed bodies of water...
            
            , Balaenoptera borealis
          • Bryde's whale
            Bryde's Whale
            Bryde's whales are baleen whales, one of the "great whales" or rorquals. They prefer tropical and temperate waters over the polar seas that other whales in their family frequent. They are largely coastal rather than pelagic. Bryde's whales are very similar in appearance to sei whales and almost as...
            
            , Balaenoptera brydei
          • Eden's whale Balaenoptera edeni – Rice lists this as a separate species, MSW3 does not
          • Omura's whale – MSW3 lists this is a synonym of Bryde's whale but suggests this may be temporary.
          • Blue whale
            Blue Whale
            The blue whale is a marine mammal belonging to the suborder of baleen whales . At in length and or more in weight, it is the largest known animal to have ever existed....
            
            , Balaenoptera musculus
          • Fin whale
            Fin Whale
            The fin whale , also called the finback whale, razorback, or common rorqual, is a marine mammal belonging to the suborder of baleen whales. It is the second longest whale and the sixth largest living animal after the blue whale, bowhead whale, and right whales, growing to nearly 27 metres long...
            
            , Balaenoptera physalus
      • Subfamily Megapterinae
        • Genus Megaptera
          • Humpback whale
            Humpback Whale
            The humpback whale is a species of baleen whale. One of the larger rorqual species, adults range in length from and weigh approximately . The humpback has a distinctive body shape, with unusually long pectoral fins and a knobbly head. It is an acrobatic animal, often breaching and slapping the...
            
            , Megaptera novaeangliae
    • Family Eschrichtiidae
      Eschrichtiidae
      Eschrichtiidae is a family of baleen whales in the suborder Mysticeti.At least five genera are recognised, but only a single species from one genus is still alive, the gray whale, Eschrichtius robustus....
      
      
      • Genus Eschrichtius
        • Gray whale
          Gray Whale
          The gray whale, Eschrichtius robustus, is a baleen whale that migrates between feeding and breeding grounds yearly. It reaches a length of about , a weight of , and lives 50–70 years. The common name of the whale comes from the gray patches and white mottling on its dark skin. Gray whales were...
          
          , Eschrichtius robustus
    • Family Neobalaenidae: Pygmy Right Whale
      • Genus Caperea
        • Pygmy right whale
          Pygmy Right Whale
          The pygmy right whale is a baleen whale, the sole member of the family Neobalaenidae. First described by John Edward Gray in 1846, it is the smallest of the baleen whales, ranging between and in length and 3,000 and 3,500 kg in mass...
          
          , Caperea marginata
  • Suborder Odontoceti: toothed whales
    • Family Delphinidae: Dolphin
      Dolphin
      Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
      
      
      • Genus Cephalorhynchus
        Cephalorhynchus
        Cephalorhynchus is a genus in the dolphin family Delphinidae. It consists of four species:*Commerson's Dolphin, Cephalorhyncus commersonii*Chilean Dolphin, Cephalorhyncus eutropia*Heaviside's Dolphin, Cephalorhyncus heavisidii...
        
        
        • Commerson's dolphin
          Commerson's Dolphin
          Commerson's Dolphin is one of four dolphins in the Cephalorhynchus genus. The species has also the common names Skunk Dolphin, Piebald Dolphin and Panda Dolphin...
          
          , Cephalorhyncus commersonii
        • Chilean dolphin
          Chilean Dolphin
          The Chilean Dolphin , also known as the Black Dolphin, is one of four dolphins in the Cephalorhynchus genus. The dolphin is only found off the coast of Chile, it is commonly referred to in the country as Tunina....
          
          , Cephalorhyncus eutropia
        • Heaviside's dolphin
          Heaviside's Dolphin
          The Haviside's Dolphin , or mistakenly the Heaviside's Dolphin, is a small dolphin that is found off the coast of Namibia and the west coast of South Africa...
          
          , Cephalorhyncus heavisidii
        • Hector's dolphin
          Hector's Dolphin
          Hector's dolphin is the best-known of the four dolphins in the genus Cephalorhynchus and is found only in New Zealand. At about 1.4 m in length, it is one of the smallest cetaceans....
          
          , Cephalorhyncus hectori
      • Genus Delphinus
        • Long-beaked common dolphin
          Long-beaked Common Dolphin
          The Long-beaked Common Dolphin is a species of common dolphin. It has a more restricted range than the Short-beaked Common Dolphin . It has a disjointed range in coastal areas in tropical and warmer temperate oceans...
          
          , Delphinus capensis
        • Short-beaked common dolphin
          Short-beaked Common Dolphin
          The short-beaked common dolphin is a species of common dolphin. It has a larger range than the long-beaked common dolphin , occurring throughout warm-temperate and tropical oceans, with the possible exception of the Indian Ocean...
          
          , Delphinus delphis
        • Arabian common dolphin, Delphinus tropicalis. Rice recognises this as a separate species. MSW3 does not.
      • Genus Feresa
        • Pygmy killer whale
          Pygmy Killer Whale
          The pygmy killer whale is a small, rarely seen cetacean of the oceanic dolphin family . It derives its common name from sharing some physical characteristics with the orca It is the smallest species that has "whale" in its common name. In fact, "killer" may be more apt in the case of the pygmy...
          
          , Feresa attenuata
      • Genus Globicephala
        • Short-finned pilot whale
          Short-finned Pilot Whale
          The Short-finned Pilot Whale is one of the two species of cetacean in the genus Globicephala. It is part of the oceanic dolphin family , though its behaviour is closer to that of the larger whales....
          
          , Globicephala macrorhyncus
        • Long-finned pilot whale
          Long-finned Pilot Whale
          The long-finned pilot whale is one of the two species of cetacean in the genus Globicephala. It belongs to the oceanic dolphin family , though its behavior is closer to that of the larger whales.-Description:...
          
          , Globicephala melas
      • Genus Grampus
        • Risso's dolphin
          Risso's Dolphin
          Risso's dolphin is the only species of dolphin in the genus Grampus.-Taxonomy:Risso's dolphin is named after Antoine Risso, whose description formed the basis of the first public description of the animal, by Georges Cuvier, in 1812...
          
          , Grampus griseus
      • Genus Lagenodelphis
        • Fraser's dolphin
          Fraser's Dolphin
          Fraser's Dolphin or Sarawak Dolphin is a cetacean in the family Delphinidae found in deep waters in the Pacific Ocean and to a lesser extent in the Indian and Atlantic Oceans.-Taxonomy:...
          
          , Lagenodelphis hosei
      • Genus Lagenorhynchus
        Lagenorhynchus
        Lagenorhynchus is a genus in the order Cetacea, traditionally containing six species:* white-beaked dolphin, Lagenorhynchus albirostris* Atlantic white-sided dolphin, Lagenorhynchus acutus...
        
        
        • Atlantic white-sided dolphin
          Atlantic White-sided Dolphin
          The Atlantic White-sided Dolphin is a distinctively coloured dolphin found in the cool to temperate waters of the North Atlantic Ocean.-Taxonomy:...
          
          , Lagenorhynchus acutus
        • White-beaked dolphin
          White-beaked Dolphin
          The White-beaked dolphin is a marine mammal belonging to the family Delphinidae in the suborder Odontoceti .-Taxonomy:...
          
          , Lagenorhynchus albirostris
        • Peale's dolphin
          Peale's Dolphin
          Peale's Dolphin is a small dolphin found in the waters around Tierra del Fuego at the foot of South America. It is also commonly known as the Black-chinned Dolphin or even Peale's Black-chinned Dolphin...
          
          , Lagenorhynchus australis
        • Hourglass dolphin
          Hourglass Dolphin
          The hourglass dolphin is a small dolphin in the family Delphinidae that inhabits Antarctic and sub-Antarctic waters....
          
          , Lagenorhynchus cruciger
        • Pacific white-sided dolphin
          Pacific White-sided Dolphin
          The Pacific White-sided Dolphin is a very active dolphin found in the cool to temperate waters of the North Pacific Ocean.-Taxonomy:...
          
          , Lagenorhynchus obliquidens
        • Dusky dolphin
          Dusky Dolphin
          The dusky dolphin is a dolphin found in coastal waters in the Southern Hemisphere. Its specific epithet is Latin for "dark" or "dim". It is very closely genetically related to the Pacific white-sided dolphin, but current scientific consensus is that they are distinct species...
          
          , Lagenorhynchus obscurus
      • Genus Lissodelphis
        • Northern right whale dolphin
          Northern Right Whale Dolphin
          The Northern right whale dolphin is a small and slender species of marine mammal found in the North Pacific Ocean. The Northern right whale dolphin travels in groups of up to 2000, often with other cetaceans, in deep waters of the North Pacific...
          
          , Lissodelphis borealis
        • Southern right whale dolphin
          Southern Right Whale Dolphin
          The southern right whale dolphin, Lissodelphis peronii, is a small and slender species of mammal found in cool waters of the southern hemisphere...
          
          , Lissodelphis peronii
      • Genus Orcaella
        Orcaella
        The snubfin dolphins are a genus of dolphins containing two members: the Irrawaddy Dolphin and Australian Snubfin Dolphin. The genus was long believed to be monotypic with the only species being the Irrawaddy Dolphin; however, in 2005, genetic analysis showed that the Australian Snubfin Dolphin is...
        
        
        • Irrawaddy Dolphin
          Irrawaddy dolphin
          The Irrawaddy dolphin is a euryhaline species of oceanic dolphin found in discontinuous subpopulations near sea coasts and in estuaries and rivers in parts of the Bay of Bengal and Southeast Asia.-Etymology and taxonomic history:...
          
          , Orcaella brevirostris
          • Australian snubfin dolphin
            Australian Snubfin Dolphin
            The Australian snubfin dolphin is a dolphin found off the northern coasts of Australia. It closely resembles the Irrawaddy dolphin and was not described as a separate species until 2005. The Australian snubfin is tri-coloured, while the Irrawaddy dolphin only has two colours on its skin...
            
            , 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
          Melon-headed Whale
          The melon-headed whale is a cetacean of the oceanic dolphin family . It is closely related to the pygmy killer whale and pilot whale, and collectively these dolphin species are known by the common name blackfish. It is also related to the false killer whale...
          
          , Peponocephala electra
      • Genus Pseudorca
        • False killer whale
          False Killer Whale
          The False Killer Whale is a cetacean, and the third largest member of the oceanic dolphin family . It lives in temperate and tropical waters throughout the world. As its name implies, the False Killer Whale shares characteristics, such as appearance, with the more widely known Orca...
          
          , Pseudorca crassidens
      • Genus Sotalia
        • Tucuxi
          Tucuxi
          The Tucuxi , alternately bufeo gris or bufeo negro is a dolphin found in the rivers of the Amazon Basin. The word "tucuxi" is derived from the Tupi language word tuchuchi-ana and has now been adopted as the species' common name...
          
          , Sotalia fluviatilis, see the species article for a discussion
        • Costero
          Costero
          The Costero is found in the coastal waters to the north and east of South America. The common name "costero" has been suggested by Caballero and colleagues due to the species' affinity for coastal habitats. The Costero is a member of the oceanic dolphin family . Physically it resembles the...
          
          , Sotalia guianensis, 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
        Stenella
        Stenella is a genus of aquatic mammals in Delphinidae, the family informally known as the oceanic dolphins.Currently five species are recognised in this genus:*Pantropical Spotted Dolphin, S. attenuata*Atlantic Spotted Dolphin, S. frontalis...
        
        
        • Pantropical spotted dolphin
          Pantropical Spotted Dolphin
          The Pantropical Spotted Dolphin is a species of dolphin found in all the world's temperate and tropical oceans. The species was beginning to come under threat due to the killing of millions of individuals in tuna purse seines...
          
          , Stenella attenuata
        • Clymene dolphin
          Clymene Dolphin
          The Clymene dolphin , in older texts known as the Short-snouted spinner dolphin, is a dolphin endemic to the Atlantic Ocean.- Taxonomy :...
          
          , Stenella clymene
        • Striped dolphin
          Striped Dolphin
          The Striped Dolphin is an extensively studied dolphin that is found in temperate and tropical waters of all the world's oceans.-Taxonomy:...
          
          , Stenella coeruleoalba
        • Atlantic spotted dolphin
          Atlantic Spotted Dolphin
          The Atlantic Spotted Dolphin is a dolphin found in the Gulf Stream of the North Atlantic Ocean. Older members of the species have a very distinctive spotted coloration all over their body.-Taxonomy:...
          
          , Stenella frontalis
        • Spinner dolphin
          Spinner Dolphin
          The Spinner Dolphin is a small dolphin found in off-shore tropical waters around the world. It is famous for its acrobatic displays in which they spin longitudinally along their axis as they leap through the air.-Taxonomy:...
          
          , Stenella longirostris
      • Genus Steno
        • Rough-toothed dolphin
          Rough-toothed Dolphin
          The Rough-toothed dolphin is species of dolphin that can be found in deep warm and tropical waters around the world.The species was first described by Georges Cuvier in 1823...
          
          , 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
        • Burrunan dolphin
          Burrunan dolphin
          The Burrunan dolphin is a recently-described species of bottlenose dolphin found in parts of Victoria, Australia. By size, the Burrunan dolphin is between the other two species of bottlenose dolphin and only around 150 individuals have been found in two locations.-Taxonomy:The species was formally...
          
          , Tursiops australis
        • Common bottlenose dolphin
          Common Bottlenose Dolphin
          Tursiops truncatus, commonly known as the Common Bottlenose Dolphin, is the most well-known species from the family Delphinidae.Common bottlenose dolphins are the most familiar dolphins due to the wide exposure they receive in captivity in marine parks, dolphinarias, in movies, and television...
          
          , Tursiops truncatus
    • Family Monodontidae
      Monodontidae
      The cetacean family Monodontidae comprises two unusual whale species, the narwhal, in which the male has a long tusk, and the white beluga whale...
      
      
      • Genus Delphinapterus
        • Beluga, Delphinapterus leucas
      • Genus Monodon
        • Narwhal
          Narwhal
          The narwhal, Monodon monoceros, is a medium-sized toothed whale that lives year-round in the Arctic. One of two living species of whale in the Monodontidae family, along with the beluga whale, the narwhal males are distinguished by a characteristic long, straight, helical tusk extending from their...
          
          , Monodon monoceros
    • Family Phocoenidae: Porpoise
      Porpoise
      Porpoises are small cetaceans of the family Phocoenidae; they are related to whales and dolphins. They are distinct from dolphins, although the word "porpoise" has been used to refer to any small dolphin, especially by sailors and fishermen...
      
      s
      • Genus Neophocaena
        • Finless Porpoise
          Finless Porpoise
          The finless porpoise is one of six porpoise species. In the waters around Japan, at the northern end of its range, it is known as the sunameri . A freshwater population found in the Yangtze River in China is known locally as the jiangzhu or "river pig". There is a degree of taxonomic uncertainty...
          
          , Neophocaena phocaenoides
      • Genus Phocoena
        • Spectacled porpoise
          Spectacled Porpoise
          The Spectacled Porpoise is a rarely seen member of the porpoise family. The species is readily distinguished from other porpoises by a characteristic dark ring around the eyes, which gives the animals their name. This ring is commonly surrounded by a farther lighter ring...
          
          , Phocoena dioptrica
        • Harbour porpoise
          Harbour Porpoise
          The harbour porpoise is one of six species of porpoise. It is one of the smallest marine mammals. As its name implies, it stays close to coastal areas or river estuaries, and as such, is the most familiar porpoise to whale watchers. This porpoise often ventures up rivers, and has been seen...
          
          , Phocoena phocaena
        • Vaquita
          Vaquita
          The vaquita is a rare species of porpoise. It is endemic to the northern part of the Gulf of California. Estimates of the number of individuals alive range from 100 to 300. The word "vaquita" is Spanish for little cow...
          
          , Phocoena sinus
        • Burmeister's porpoise
          Burmeister's Porpoise
          Burmeister's Porpoise is a species of porpoise endemic to the coast of South America. It was first described by Hermann Burmeister, for whom the species is named, in 1865...
          
          , Phocoena spinipinnis
      • Genus Phocoenoides
        • Dall's porpoise
          Dall's Porpoise
          Dall's porpoise is a species of porpoise found on the North Pacific. It came to worldwide attention in the 1970s when it was disclosed for the first time to the public that salmon fishing trawls were killing a lot, thousands of Dall's porpoises and other cetaceans each year by accidentally...
          
          , Phocoenoides dalli
    • Family Physeteridae: Sperm whale family
      Sperm whale family
      Physeteroidea is a superfamily including just three living species of whale; the Sperm Whale, in the genus Physeter, and the Pygmy Sperm Whale and Dwarf Sperm Whale, in the genus Kogia...
      
      
      • Genus Physeter
        • Sperm whale
          Sperm Whale
          The sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...
          
          , Physeter catodon (syn. P. macrocephalus)
    • Family Kogiidae – MSW3 treats Kogia as a member of Physeteridae
      • Genus Kogia
        • Pygmy sperm whale
          Pygmy Sperm Whale
          The Pygmy Sperm Whale is one of three species of toothed whale in the sperm whale family. They are not often sighted at sea, and most of what is known about them comes from the examination of stranded specimens.-Taxonomy:...
          
          , Kogia breviceps
        • Dwarf sperm whale
          Dwarf Sperm Whale
          The Dwarf Sperm Whale is one of three species in the sperm whale family. They are not often sighted at sea. As such, most information is a result of the study of stranded carcasses.-Taxonomy:...
          
          , Kogia sima
    • Superfamily Platanistoidea: River dolphins
      • Family Iniidae
        Iniidae
        Iniidae is a family of river dolphins containing one living and three extinct genera.-Taxonomy:The family was described by John Edward Gray in 1846.Current classifications include a single living genera, Inia, with one species and three subspecies...
        
        
        • Genus Inia
          Inia
          Inia is a genus of river dolphin containing one or possibly two species.-Taxonomy:The genus was described by Alcide d'Orbigny in 1834 when Delphinus geoffrensis, described by Henri Marie Ducrotay de Blainville in 1817, was recognized to be a unique taxon...
          
          
          • Amazon river dolphin, Inia geoffrensis
            • Bolivian river dolphin
              Bolivian River Dolphin
              The Bolivian river dolphin is a subspecies of the Amazon river dolphin. Although older publications as well as some recent publications consider the boliviensis population as distinct species from Inia geoffrensis, the great majority of the scientific community including the IUCN consider...
              
              , Inia boliviensis
      • † 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
          La Plata Dolphin
          The La Plata Dolphin or Franciscana is found in coastal Atlantic waters of southeastern South America. Taxonomically it is a member of the river dolphin group and the only one that actually lives in the ocean and saltwater estuaries, rather than inhabiting exclusively freshwater...
          
          
          • La Plata dolphin
            La Plata Dolphin
            The La Plata Dolphin or Franciscana is found in coastal Atlantic waters of southeastern South America. Taxonomically it is a member of the river dolphin group and the only one that actually lives in the ocean and saltwater estuaries, rather than inhabiting exclusively freshwater...
            
            , Pontoporia blainvillei
      • Family Platanistidae
        • Genus Platanista
          • Ganges and Indus River dolphin
            Ganges and Indus River Dolphin
            The South Asian River Dolphin is a freshwater or river dolphin found in India, Nepal and Pakistan which is split into two sub-species, the Ganges River Dolphin and Indus River Dolphin...
            
            , Platanista gangetica. MSW3 treats Platanista minor as a separate species, with common names Ganges River Dolphin and Indus River Dolphin
            Indus River dolphin
            The Indus River dolphin is a sub-species of freshwater or river dolphin found in the Indus River of Pakistan...
            
            , respectively.
  • Superfamily Ziphioidea: Beaked whales
    • Family Ziphidae,
      • 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
          Mesoplodont whale
          Mesoplodont whales are fourteen species of whale in the genus Mesoplodon, making it the largest genus in the cetacean order. Two species were described as recently as 1991 and 2002 , and marine biologists predict the discovery of more species in the future. They are the most poorly known group of...
          
          
          • Sowerby's beaked whale
            Sowerby's Beaked Whale
            Sowerby's beaked whale , also known as the North Atlantic/North Sea beaked whale, was the first beaked whale to be described. James Sowerby, an English naturalist and artist, first described the species in 1804 from a skull obtained from a male that had stranded in the Moray Firth, Scotland, in 1800...
            
            , Mesoplodon bidens
          • Andrews' beaked whale
            Andrews' Beaked Whale
            Andrews' beaked whale , sometimes known as the deep-crest beaked whale or splay-toothed whale, is one of the most poorly known members of a poorly known genus...
            
            , Mesoplodon bowdoini
          • Hubbs' beaked whale
            Hubbs' Beaked Whale
            Hubbs' beaked whale was initially thought to be an Andrews' beaked whale when discovered by ichthyologist Carl Hubbs; however, it was named in his honor when it was discovered to be a new species. This species has the typical dentition found in the genus, but its main outstanding features are a...
            
            , Mesoplodon carlhubbsi
          • Blainville's beaked whale
            Blainville's Beaked Whale
            Blainville's beaked whale , or the dense-beaked whale, is the widest ranging mesoplodont whale and perhaps the most documented. Henri de Blainville first described the species in 1817 from a small piece of jaw—the heaviest bone he had ever come across—which resulted in the name densirostris...
            
            , Mesoplodon densirostris
          • Gervais' beaked whale
            Gervais' Beaked Whale
            Gervais' beaked whale , sometimes known as the Antillian beaked whale, Gulf Stream beaked whale, or European beaked whale is the most frequently stranding type of mesoplodont whale off the coast of North America...
            
            , Mesoplodon europaeus
          • Ginkgo-toothed beaked whale
            Ginkgo-toothed Beaked Whale
            The ginkgo-toothed beaked whale is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth...
            
            , Mesoplodon ginkgodens
          • Gray's beaked whale
            Gray's Beaked Whale
            Gray's beaked whale , sometimes known as Haast's beaked whale, the Scamperdown whale, or the southern beaked whale, is one of the better-known members of the genus Mesoplodon. The scientific name refers to John Edward Gray, a zoologist at the British Museum. This species is fairly gregarious and...
            
            , Mesoplodon grayi
          • Hector's beaked whale
            Hector's Beaked Whale
            Hector's beaked whale , is a small mesoplodont living in the Southern Hemisphere. This whale is named after Sir James Hector, a founder of the colonial museum in Wellington, New Zealand...
            
            , Mesoplodon hectori
          • Strap-toothed whale, Mesoplodon layardii
          • True's beaked whale
            True's Beaked Whale
            The True's Beaked Whale is a medium sized whale in the Mesoplodont genus. The common name is in reference to Frederick W. True, a curator at the United States National Museum...
            
            , Mesoplodon mirus
          • Perrin's beaked whale
            Perrin's Beaked Whale
            Perrin's beaked whale is the newest species of beaked whale to be described. The first two specimens were found in May 1975 stranded on the California coast, with two more specimens being found in 1978 and 1979, and the last in September 1997...
            
            , Mesoplodon perrini. This species was recognised in 2002 and as such is listed by MSW3 but not Rice.
          • Pygmy beaked whale
            Pygmy Beaked Whale
            The pygmy beaked whale , also known as the bandolero beaked whale, Peruvian beaked whale and lesser beaked whale, is the smallest of the mesoplodonts and one of the newest discoveries. There were at least two dozen sightings of an unknown beaked whale named Mesoplodon sp...
            
            , Mesoplodon peruvianus
          • Stejneger's beaked whale
            Stejneger's Beaked Whale
            Stejneger's beaked whale , sometimes known as the Bering Sea beaked whale or the Saber-toothed whale, is a poorly-known member of the genus Mesoplodon inhabiting the northern North Pacific Ocean. Leonhard Hess Stejneger initially described the species in 1885 from a skull, and nothing more of the...
            
            , Mesoplodon stejnegeri
          • Spade-toothed whale, Mesoplodon traversii
      • Genus Tasmacetus
        • Shepherd's beaked whale
          Shepherd's Beaked Whale
          Shepherd's beaked whale , also commonly called Tasman's beaked whale or simply the Tasman whale, is a cetacean of the family Ziphidae. The whale has been little studied. Only four confirmed at sea sightings have been made and 42 strandings recorded . It was first known to science in 1937, being...
          
          , Tasmacetus shepherdi
      • Genus Ziphius
        • Cuvier's beaked whale
          Cuvier's Beaked Whale
          Cuvier's beaked whale is the most widely distributed of all the beaked whales. It is the only member of the genus Ziphius. Another common name for the species is goose-beaked whale because its head is said to be shaped like the beak of a goose. Georges Cuvier first described it in 1823 from part...
          
          , Ziphius cavirostris

†Recently extinct

External links

Including a page on taxonomy

• EIA Cetacean campaign: Reports and latest info.
• EIA in USA: reports etc.