Portal:Cetaceans

The Cetaceans Portal

A Sperm Whale fluke

Cetacea (/sɪˈteɪʃə/; from Latin cetus 'whale', from Ancient Greek κῆτος (kêtos) 'huge fish, sea monster') is an infraorder of aquatic mammals belonging to the order Artiodactyla that includes whales, dolphins and porpoises. Key characteristics are their fully aquatic lifestyle, streamlined body shape, often large size and exclusively carnivorous diet. They propel themselves through the water with powerful up-and-down movement of their tail which ends in a paddle-like fluke, using their flipper-shaped forelimbs to maneuver.

While the majority of cetaceans live in marine environments, a small number reside solely in brackish water or fresh water. Having a cosmopolitan distribution, they can be found in some rivers and all of Earth's oceans, and many species inhabit vast ranges where they migrate with the changing of the seasons.

Cetaceans are famous for their high intelligence, complex social behaviour, and the enormous size of some of the group's members. For example, the blue whale reaches a maximum confirmed length of 29.9 meters (98 feet) and a weight of 173 tonnes (190 short tons), making it the largest animal ever known to have existed.

There are approximately 89 living species split into two parvorders: Odontoceti or toothed whales (containing porpoises, dolphins, other predatory whales like the beluga and the sperm whale, and the poorly understood beaked whales) and the filter feeding Mysticeti or baleen whales (which includes species like the blue whale, the humpback whale and the bowhead whale). Despite their highly modified bodies and carnivorous lifestyle, genetic and fossil evidence places cetaceans as nested within even-toed ungulates, most closely related to hippopotamus within the clade Whippomorpha. (Full article...)

Recognized content -

Entries here consist of Good and Featured articles, which meet a core set of high editorial standards.

---

• 
  
  

  

  Top (left) and underside (right) views of the skull

  
  Kogia pusilla is an extinct species of sperm whale from the Middle Pliocene of Italy, also known as the Littleness Sperm Whale. related to the modern-day dwarf sperm whale (K. sima) and pygmy sperm whale (K. breviceps). It is known from a single skull discovered in 1877, and was considered a species of beaked whale until 1997. The skull shares many characteristics with other sperm whales, and is comparable in size to that of the dwarf sperm whale. Like the modern Kogia, it probably hunted squid in the twilight zone, and frequented continental slopes. The environment it inhabited was likely a calm, nearshore area with a combination sandy and hard-rock seafloor. K. pusilla likely died out due to the ice ages at the end of the Pliocene. (Full article...)
• 

  

  
  The sperm whale or cachalot (Physeter macrocephalus) is the largest of the toothed whales and the largest toothed predator. It is the only living member of the genus Physeter and one of three extant species in the sperm whale family, along with the pygmy sperm whale and dwarf sperm whale of the genus Kogia.
  
  The sperm whale is a pelagic mammal with a worldwide range, and will migrate seasonally for feeding and breeding. Females and young males live together in groups, while mature males (bulls) live solitary lives outside of the mating season. The females cooperate to protect and nurse their young. Females give birth every four to twenty years, and care for the calves for more than a decade. A mature, healthy sperm whale has no natural predators, although calves and weakened adults are sometimes killed by pods of killer whales (orcas). (Full article...)
• 
  
  

  

  The holotype and only specimen

  
  Orcinus meyeri is a fossil species of Orcinus (killer whales) found in the Early Miocene deposits of southern Germany, known from two jaw fragments and 18 isolated teeth. It was originally described as Delphinus acutidens in 1859, but reclassified in 1873. Its validity is disputed, and it may be a synonymous with the ancient sperm whale Physeterula dubusi. It was found in the Alpine town of Stockach in the Molasse basin, which was a coastal area with strong tidal currents. (Full article...)
• 
  
  

  

  Cast of skull at the Natural History Museum of the University of Pisa

  
  Livyatan is an extinct genus of macroraptorial sperm whale containing one known species: L. melvillei. The genus name was inspired by the biblical sea monster Leviathan, and the species name by Herman Melville, the author of the famous novel Moby-Dick about a white bull sperm whale. Herman Melville often referred to whales as "Leviathans" in his book. It is mainly known from the Pisco Formation of Peru during the Tortonian stage of the Miocene epoch, about 9.9–8.9 million years ago (mya); however, finds of isolated teeth from other locations such as Chile, Argentina, the United States (California), South Africa and Australia imply that either it or a close relative survived into the Pliocene, around 5 mya, and may have had a global presence. It was a member of a group of macroraptorial sperm whales (or "raptorial sperm whales") and was probably an apex predator, preying on whales, seals and so forth. Characteristically of raptorial sperm whales, Livyatan had functional, enamel-coated teeth on the upper and lower jaws, as well as several features suitable for hunting large prey.
  
  Livyatan's total length has been estimated to be about 13.5–17.5 m (44–57 ft), almost similar to that of the modern sperm whale (Physeter macrocephalus), making it one of the largest predators known to have existed. The teeth of Livyatan measured 36.2 cm (1.19 ft), and are the largest biting teeth of any known animal, excluding tusks. It is distinguished from the other raptorial sperm whales by the basin on the skull spanning the length of the snout. The spermaceti organ contained in that basin is thought to have been used in echolocation and communication, or for ramming prey and other sperm whales. The whale may have interacted with the large extinct shark megalodon (Otodus megalodon), competing with it for a similar food source. Its extinction was probably caused by a cooling event at the end of the Miocene period causing a reduction in food populations. The geological formation where the whale has been found has also preserved a large assemblage of marine life, such as sharks and marine mammals. (Full article...)
• 
  
  

  

  A fin whale surfacing in Greenland

  
  The fin whale (Balaenoptera physalus), also known as the finback whale or common rorqual, is a species of baleen whale and the second-longest cetacean after the blue whale. The biggest individual reportedly measured 26 m (85 ft) in length, with a maximum recorded weight of 77 to 81 tonnes. The fin whale's body is long, slender and brownish-gray in color, with a paler underside to appear less conspicuous from below (countershading).
  
  At least two recognized subspecies exist, one in the North Atlantic and one across the Southern Hemisphere. It is found in all the major oceans, from polar to tropical waters, though it is absent only from waters close to the pack ice at the poles and relatively small areas of water away from the open ocean. The highest population density occurs in temperate and cool waters. Its prey mainly consists of smaller schooling fish, small squid, or crustaceans, including copepods and krill. Mating takes place in temperate, low-latitude seas during the winter. Fin whales are often observed in pods of 6–10 animals, with whom they communicate utilizing frequency-modulated sounds, ranging from 16 to 40 hertz. (Full article...)
• 
  
  

  

  Holotype skull of A. deinodon

  
  Acrophyseter is a genus of extinct sperm whale that lived in the Late Miocene off the coast of what is now Peru. The genus comprises two species: A. deinodon and A. robustus. It is part of a group of macroraptorial sperm whales that all share several features for hunting large prey, such as deeply rooted and thick teeth. Acrophyseter measured 4–4.5 metres (13–15 ft) in length, making it the smallest macroraptorial sperm whale currently known. Because of its short pointed snout and strongly curved front teeth, it probably fed on the large marine vertebrates of its time, such as seals and other whales. (Full article...)
• 

  

  
  Pilot whales are cetaceans belonging to the genus Globicephala. The two extant species are the long-finned pilot whale (G. melas) and the short-finned pilot whale (G. macrorhynchus). The two are not readily distinguishable at sea, and analysis of the skulls is the best way to distinguish between the species. Between the two species, they range nearly worldwide, with long-finned pilot whales living in colder waters and short-finned pilot whales living in tropical and subtropical waters. Pilot whales are among the largest of the oceanic dolphins, exceeded in size only by the orca. They and other large members of the dolphin family are also known as blackfish.
  
  Pilot whales feed primarily on squid, but will also hunt large demersal fish such as cod and turbot. They are highly social and may remain with their birth pod throughout their lifetime. Short-finned pilot whales are one of the few non-primate mammal species in which females go through menopause, and postreproductive females continue to contribute to their pod. Pilot whales are notorious for stranding themselves on beaches, but the reason behind this is not fully understood. Marine biologists have shed some light on the matter, suggesting that it is due to the mammals inner ear (their principal navigational sonar) being damaged from noise pollution in the ocean, such as from cargo ships or military exercises. The conservation status of short-finned and long-finned pilot whales has been determined to be least concern. (Full article...)
• 
  
  

  

  Skull of Janjucetus hunderi at the Melbourne Museum

  
  Janjucetus is an extinct genus of cetacean, and a basal baleen whale (Mysticeti), from the Late Oligocene around 25 million years ago (mya) off south-east Australia, containing one species J. hunderi. Unlike modern mysticetes, it possessed large teeth for gripping and shredding prey, and lacked baleen, and so was likely to have been a predator that captured large single prey animals rather than filter feeding. However, its teeth may have interlocked, much like those of the modern-day filter-feeding crabeater seal (Lobodon carcinophaga), which would have allowed some filter-feeding behaviour. Its hunting behaviour was probably similar to the modern-day leopard seal (Hydrurga leptonyx), probably eating large fish. Like baleen whales, Janjucetus could not echolocate; however, it did have unusually large eyes, and so probably had an acute sense of vision. The only specimen was found on the Jan Juc beach, where the remains of the extinct whales Mammalodon, Prosqualodon and Waipatia have also been discovered. (Full article...)
• 

  

  
  The false killer whale (Pseudorca crassidens) is a species of oceanic dolphin that is the only extant representative of the genus Pseudorca. It is found in oceans worldwide but mainly in tropical regions. It was first described in 1846 as a species of porpoise based on a skull, which was revised when the first carcasses were observed in 1861. The name "false killer whale" comes from having a skull similar to the orca (Orcinus orca), or killer whale.
  
  The false killer whale reaches a maximum length of 6 m (20 ft), though size can vary around the world. It is highly sociable, known to form pods of up to 50 members, and can also form pods with other dolphin species, such as the common bottlenose dolphin (Tursiops truncatus). It can form close bonds with other species, as well as have sexual interactions with them. But the false killer whale has also been known to eat other dolphins, though it typically eats squid and fish. It is a deep-diver; maximum known depth is 927.5 m (3,043 ft); maximum speed is ~ 29 km/h (18 mph). (Full article...)
• 

  

  
  The humpback whale (Megaptera novaeangliae) is a species of baleen whale. It is a rorqual (a member of the family Balaenopteridae) and is the only species in the genus Megaptera. Adults range in length from 14–17 m (46–56 ft) and weigh up to 40 metric tons (44 short tons). The humpback has a distinctive body shape, with long pectoral fins and tubercles on its head. It is known for breaching and other distinctive surface behaviors, making it popular with whale watchers. Males produce a complex song typically lasting 4 to 33 minutes.
  
  Found in oceans and seas around the world, humpback whales typically migrate up to 16,000 km (9,900 mi) each year. They feed in polar waters and migrate to tropical or subtropical waters to breed and give birth. Their diet consists mostly of krill and small fish, and they use bubbles to catch prey. They are promiscuous breeders, with both sexes having multiple partners. Orcas are the main natural predators of humpback whales. (Full article...)
• 
  
  

  

  Clockwise from top left: humpback whale, gray whale, North Atlantic right whale, and common minke whale

  
  Baleen whales (/bəˈliːn/), also known as whalebone whales, are marine mammals of the parvorder Mysticeti in the infraorder Cetacea (whales, dolphins and porpoises), which use keratinaceous baleen plates (or "whalebone") in their mouths to sieve planktonic creatures from the water. Mysticeti comprises the families Balaenidae (right and bowhead whales), Balaenopteridae (rorquals), Eschrichtiidae (the gray whale) and Cetotheriidae (the pygmy right whale). There are currently 16 species of baleen whales. While cetaceans were historically thought to have descended from mesonychians, molecular evidence instead supports them as a clade of even-toed ungulates (Artiodactyla). Baleen whales split from toothed whales (Odontoceti) around 34 million years ago.
  
  Baleen whales range in size from the 6 m (20 ft) and 3,000 kg (6,600 lb) pygmy right whale to the 31 m (102 ft) and 190 t (210 short tons) blue whale, the largest known animal to have ever existed. They are sexually dimorphic. Baleen whales can have streamlined or large bodies, depending on the feeding behavior, and two limbs that are modified into flippers. The fin whale is the fastest baleen whale, recorded swimming at 10 m/s (36 km/h; 22 mph). Baleen whales use their baleen plates to filter out food from the water by either lunge-feeding or skim-feeding. Baleen whales have fused neck vertebrae, and are unable to turn their heads at all. Baleen whales have two blowholes. Some species are well adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water. (Full article...)
• 

  

  Boudewijn Seapark dolphinarium in Bruges, Belgium

  
  A dolphinarium is an aquarium for dolphins. The dolphins are usually kept in a pool, though occasionally they may be kept in pens in the open sea, either for research or public performances. Some dolphinariums (sometimes called dolphinaria in plural) consist of one pool where dolphins perform for the public, others are part of larger parks, such as marine mammal parks, zoos or theme parks, with other animals and attractions as well.
  
  While cetaceans have been held in captivity since the 1860s, the first commercial dolphinarium was opened only in 1938. Their popularity increased rapidly until the 1960s. Since the 1970s, increasing concern for animal welfare led to stricter regulation, which in several countries ultimately resulted in the closure of some dolphinariums. Despite this trend, dolphinariums are still widespread in Europe, Japan and North America. The most common species of dolphin kept in dolphinariums is the bottlenose dolphin, as it is relatively easy to train and has a long lifespan in captivity. While trade in dolphins is internationally regulated, other aspects of keeping dolphins in captivity, such as the minimum size and characteristics of pools, vary among countries. Though animal welfare is perceived to have improved significantly over the last few decades, many animal rights groups still consider keeping dolphins captive to be a form of animal abuse. (Full article...)
• 

  

  
  Granny (born c. 1936-1951 approx, died c. 2016), also known as J2, was a female orca of the J pod of southern resident orcas notable for her long life. Early estimates placed her birth in 1911, putting her at 105 years old at the time of her death. However, this estimate was later theorized to have been based on mistaken information and more recent studies put her at 65–80 years old. If she was 105, she would have been the oldest known orca at the time of her death. Granny lived in the northeast Pacific Ocean and coastal bays of Washington state and British Columbia. She was last seen on October 12, 2016, and was considered deceased by The Center for Whale Research in January 2017. (Full article...)
• 
  
  

  

  Restored skeleton

  
  Brygmophyseter, known as the biting sperm whale, is an extinct genus of toothed whale in the sperm whale family with one species, B. shigensis. When it was first described in 1994, the species was placed in the genus Scaldicetus based on tooth morphology, but this was later revised in 1995. In 2006, it was classified into the genus Naganocetus, which is considered to be a junior synonym. The only known specimen, a nearly complete skeleton, was dated to be around 16–15 million years old (middle Miocene). Brygmophyseter is thought to have been 6.5–7 meters (21–23 ft) long, and it probably had 11 or 12 teeth in the upper and lower jaws. Brygmophyseter is part of a group of macroraptorial sperm whales (often shortened to "raptorial") which tended to be apex predators using their large teeth to catch struggling prey such as whales. It had a spermaceti organ which was probably used for biosonar like in the modern sperm whale. The whale has made an appearance on The History Channel's TV series Jurassic Fight Club. (Full article...)
• 
  
  

  

  Artistic reconstruction

  
  Arktocara is an extinct genus of river dolphin from the Oligocene epoch of Alaska, containing one species, A. yakataga. Having been discovered in 25-million-year-old strata near the 60th parallel north, it is perhaps the oldest-known crown toothed whale and the northmost river dolphin discovered. It was a member of the now-extinct family Allodelphinidae, along with the genera Allodelphis, Goedertius, Ninjadelphis, and Zarhinocetus. It measured approximately 2.26 or 2.28 meters (7.4 or 7.5 ft), comparable to its closest living relative, the South Asian river dolphin, which measures 2.4 meters (7.9 ft). However, the animal probably had an elongated beak and neck, so it may have been longer. The animal is known only from a partially preserved skull. Its ecology may have been similar to the modern-day Dall's porpoise, and it may have competed with contemporaneous delphinoids. Its remains were found in the Poul Creek Formation, which has also yielded several mollusk species. (Full article...)

Selected picture

A pair of humpback whales lung-feeding.

Photo credit: U.S Government's Minerals Management Service

Humpback Whales blow a curtain of bubbles around their prey and then lunge through them with their mouths open. The Humpbacks strain the tiny creatures, called krill, through the baleen in their mouths.

More on lunge-feeding

More did you know...

A Bottlenose Dolphin Breaching the water

• ...dolphins often leap clear of the water when travelling at speed. This is because the density of water is much greater than that of air and they are able to travel faster by leaping out of the water.

• ...both whales and dolphins carry ‘whale lice’ — small crustaceans that inhabit folds in the skin of whales and dolphins, feeding off the loose skin.

• ...whale and dolphin mothers ‘suckle’ their young underwater! Mothers have muscular mammary glands and ‘squirt’ their milk into the calf’s mouth, to ensure that the calf takes in as much of the energy rich milk as possible.

• ...on average, a whale or dolphin will eat four to five percent of its body weight in food per day. That means that a 100 ton blue whale will eat almost five tons of krill per day, or that a 200kg bottlenose dolphin will eat 10kg of fish per day!

• ...newborn cetacean calves ‘suckle’ three to four times each hour and will suckle from their mothers for six months or more.

Things you can do..

Here are some Cetaceans WikiProject tasks you can do. Patrol: Look through the Category:Cetaceans for recent changes Assessment: Unassessed cetacea articles and unknown-importance cetacea articles. Copyedit/Formatting: Bottlenose dolphin, Beached whale, Cetacea Expand: Hector's beaked whale, Ginkgo-toothed beaked whale, Shepherd's beaked whale, Archaeoceti, Cumberland Sound beluga, Blubber, Baiji, Humpback dolphin, Amazon river dolphin Verify: Spinner dolphin, Whale, Dolphin, Cetacea Stubs: Bolivian river dolphin (new species), Cephalorhynchus Images: Pictures of the baiji are wanted.

General images -

The following are images from various cetacean-related articles on Wikipedia.

• 
  Anatomy of the bottlenose dolphin (from Toothed whale)
• 
  Gray whale illustration
• 
  An orca by the name of Ulises performing at SeaWorld, 2009 (from Toothed whale)
• 
  Possible relationships between cetaceans and other ungulate groups. (from Evolution of cetaceans)
• 
  Orange whale lice on a right whale
• 
  Biosonar by cetaceans (from Toothed whale)
• 
  Megalodon hunted Miocene baleen whales (from Baleen whale)
• 
  Bryde's whale (rorqual) (from Baleen whale)
• 
  Humpback whales lunge-feeding in the course of bubble net fishing
• 
  Humpback whale illustration
• 
  Bowhead whale illustration
• 
  Restoration of Janjucetus hunderi (from Baleen whale)
• 
  Japanese scientific whaling on a pair of Antarctic minke whales (from Baleen whale)
• 
  Diagram illustrating sound generation, propagation and reception in a toothed whale. Outgoing sounds are red and incoming ones are green (from Toothed whale)
• 
  Fossil of Squalodon (from Toothed whale)
• 
  Pacific white-sided dolphins porpoising (from Toothed whale)
• 
  Sei whale illustration
• 
  A protest against Japan's scientific whaling
• 
  Blue whale illustration
• 
  The remains of a North Atlantic right whale after it collided with a ship propeller
• 
  Common minke whale illustration
• 
  Archaeomysticetes, like Janjucetus, had teeth.
• 
  A humpback whale skeleton. Notice how the jaw is split into two.
• 
  Dolphins (aquatic mammals) and ichthyosaurs (extinct marine reptiles) share a number of unique adaptations for fully aquatic lifestyle and are frequently used as extreme examples of convergent evolution (from Evolution of cetaceans)
• 
  Atlantic white-sided dolphin caught in a drive hunt in Hvalba on the Faroe Islands being taken away with a forklift (from Toothed whale)
• 
  South Atlantic right whale illustration
• 
  Orca hunting a Weddell seal (from Toothed whale)
• 
  Their eyes are relatively small for their size.
• 
  Pygmy right whale illustration
• 
  Baleen whales vary considerably in size and shape, depending on their feeding behavior. (from Baleen whale)
• 
  Female right whale with calf
• 
  Archaeocetes (like this Basilosaurus) had a heterodont dentition (from Evolution of cetaceans)
• 
  Pakicetus attocki skeleton (from Evolution of cetaceans)
• 
  World population graph of blue whales
• 
  A phylogenetic tree showing the relationships among cetacean families. (from Evolution of cetaceans)
• 
  Species of the infraorder Cetacea (from Evolution of cetaceans)
• 
  Acrophyseter skull (from Evolution of cetaceans)
• 
  Eden's whale illustration
• 
  Features of a sperm whale skeleton (from Toothed whale)
• 
  Antarctic minke whale illustration
• 
  The nose of the whale is filled with a waxy substance that was widely used in candles, oil lamps, and lubricants (from Toothed whale)
• 
  North Atlantic right whale illustration
• 
  The heart of a blue whale with a person standing next to it
• 
  Accessory baleen plates taper off into small hairs (from Baleen whale)
• 
  A whale as depicted by Conrad Gessner, 1587, in his Historiae animalium (from Toothed whale)
• 
  Spectrogram of dolphin vocalizations. Whistles, whines, and clicks are visible as upside down V's, horizontal striations, and vertical lines, respectively. (from Toothed whale)
• 
  Fin whale illustration
• 
  The skeleton of a bowhead whale with the hind limb and pelvic bone structure circled in red. This bone structure stays internal during the entire life of the species. (from Evolution of cetaceans)

Did you know (auto-generated)

• ... that Celia Kaye won the Golden Globe Award for Most Promising Newcomer in 1965 for her starring role in Island of the Blue Dolphins?
• ... that one can swim with humpback whales in the Niue Nukutuluea Multiple-Use Marine Park?
• ... that the South Asian river dolphin is nearly blind and relies on echolocation for navigation?
• ... that one of the first researchers to propose dolphin-assisted therapy for humans later renounced it?

Selected media

List articles

• List of cetaceans
• List of extinct cetaceans
• List of whale species
• List of dolphin species
• List of porpoise species
• List of whale vocalizations

Related portals

WikiProjects

WikiProjects

The content you are reading was created by Wikipedia volunteers. See WikiProject Cetaceans for more.

Related WikiProjects include:

• Tree of Life
• Biology
• Science
• Birds
• Mammals
• Marine Life
• Sharks

• See also: Wikispecies, a Wikimedia project dedicated to the classification of species.

Cetacean articles

Represents a Featured article, Represents a Good article

Categories

Category puzzle

Select [►] to view subcategories

Cetaceans

Cetaceans of Europe

Cetaceans of the Pacific Ocean

Cetacean-related lists

Lists of cetaceans

Individual cetaceans

Cetacean anatomy

Archaeoceti

Baleen whales

Cetaceans and humans

Cetaceans of the Arctic Ocean

Cetaceans of the Atlantic Ocean

Cetaceans of the Indian Ocean

Cetacean diseases

Dolphins

Cetacean genera

Prehistoric cetaceans

Cetacean research and conservation

Cetaceans of the Southern Ocean

Toothed whales

Whales

Cetacean stubs

See also

For additional lists of marine life-related featured articles and good articles see:

• Portal:Fish/Recognized content
• Portal:Marine life/Recognized content
• Portal:Sharks/Selected articles

Associated Wikimedia

The following Wikimedia Foundation sister projects provide more on this subject:

• 

  Commons
  Free media repository

• 

  Wikibooks
  Free textbooks and manuals

• 

  Wikidata
  Free knowledge base

• 

  Wikinews
  Free-content news

• 

  Wikiquote
  Collection of quotations

• 

  Wikisource
  Free-content library

• 

  Wikispecies
  Directory of species

• 

  Wikiversity
  Free learning tools

• 

  Wikivoyage
  Free travel guide

• 

  Wiktionary
  Dictionary and thesaurus

Discover Wikipedia using portals

• 

  List of all portals

• 

  The arts portal

• 

  Biography portal

• 

  Current events portal

• 

  Geography portal

• 

  History portal

• 

  Mathematics portal

• 

  Science portal

• 

  Society portal

• 

  Technology portal

• 

  Random portal

• 

  WikiProject Portals