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.

---

• 

  

  
  The blue whale (Balaenoptera musculus) is a marine mammal and a baleen whale. Reaching a maximum confirmed length of 29.9 m (98 ft) and weighing up to 199 t (196 long tons; 219 short tons), it is the largest animal known ever to have existed. The blue whale's long and slender body can be of various shades of greyish-blue on its upper surface and somewhat lighter underneath. Four subspecies are recognized: B. m. musculus in the North Atlantic and North Pacific, B. m. intermedia in the Southern Ocean, B. m. brevicauda (the pygmy blue whale) in the Indian Ocean and South Pacific Ocean, and B. m. indica in the Northern Indian Ocean. There is a population in the waters off Chile that may constitute a fifth subspecies.
  
  In general, blue whale populations migrate between their summer feeding areas near the poles and their winter breeding grounds near the tropics. There is also evidence of year-round residencies, and partial or age/sex-based migration. Blue whales are filter feeders; their diet consists almost exclusively of krill. They are generally solitary or gather in small groups, and have no well-defined social structure other than mother–calf bonds. Blue whales vocalize, with a fundamental frequency ranging from 8 to 25 Hz; their vocalizations may vary by region, season, behavior, and time of day. Orcas are their only natural predators. (Full article...)
• 
  
  

  

  Cast of a skull at the Museo storia naturale di Pisa in Italy

  
  Zygophyseter varolai is an extinct sperm whale that lived during the Tortonian age of the Late Miocene 11.2 to 7.6 million years ago. It is known from a single specimen from the Pietra Leccese Formation in Italy. It was a member of a stem group of fossil macroraptorial sperm whales (often shortened to "raptorial") also including Brygmophyseter, Acrophyseter, and Livyatan. It probably grew to be around 6.5 to 7 meters (21 to 23 ft) in length and shared some characteristics with other raptorials, such as large teeth with tooth enamel that were functional in both the upper and lower jaws which the modern sperm whale (Physeter macrocephalus) lacks. It also had a beak, the ability to echolocate prey, and could have probably swum faster than the modern-day sperm whale which can reach 4 kilometers per hour (2.5 mph). These were probably used in the capture of large prey, such as large fish, seals, and whales. In fact, its common name, the killer sperm whale, refers to its feeding habits that would have had a resemblance to the modern-day killer whale (Orcinus orca). (Full article...)
• 

  

  
  The orca (Orcinus orca), or killer whale, is a toothed whale and the largest member of the oceanic dolphin family. It is the only extant species in the genus Orcinus and is recognizable by its black-and-white patterned body. A cosmopolitan species, they are found in diverse marine environments, from Arctic to Antarctic regions to tropical seas.
  
  Orcas are apex predators with a diverse diet. Individual populations often specialize in particular types of prey. This includes a variety of fish, sharks, rays, and marine mammals such as seals and other dolphins and whales. They are highly social; some populations are composed of highly stable matrilineal family groups (pods). Their sophisticated hunting techniques and vocal behaviors, often specific to a particular group and passed along from generation to generation, are considered to be manifestations of animal culture. (Full article...)
• 
  
  

  

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

  
  Kogia pusilla is an extinct species of sperm whale from the Middle Pliocene of Italy. 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 narwhal (Monodon monoceros) is a species of toothed whale native to the Arctic. It is the only member of the genus Monodon and one of two living representatives of the family Monodontidae. The narwhal has a similar build to the closely related beluga whale, with which it overlaps in range and can interbreed. It is a stocky cetacean with a relatively blunt snout, a large melon, and a shallow ridge in place of a dorsal fin. Males of this species have a large 1.5–3.0 m (4 ft 11 in – 9 ft 10 in) long tusk, which is a left protruded canine thought to serve as a weapon or as a tool for feeding, attracting mates or sensing water salinity. Specially adapted slow-twitch muscles, along with the jointed neck vertebrae and shallow dorsal ridge allow for easy movement through the Arctic environment, where the narwhal spends extended periods at great depths.
  
  The narwhal inhabits the Arctic waters of Canada, Greenland and Russia. Every year, it migrates to ice-free summering grounds, usually in shallow waters, and often returns to the same sites in subsequent years. Its diet mainly consists of polar and Arctic cod, Greenland halibut, cuttlefish, shrimp, and armhook squid. Plunging at depths of up to 2,370 m (7,780 ft), the narwhal is among the deepest-diving cetaceans. It travels in groups of three to eight, with aggregations of up to 1,000 occurring in the summer months. It mates in the offshore pack ice from March to May, and the young are born in July or August of the following year. When communicating, a variety of clicks, whistles and knocks are used. (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...)
• 

  

  The anatomist John Struthers (at left, in top hat) with the Tay Whale at John Woods's yard, Dundee, 1884, photographed by George Washington Wilson

  
  The Tay Whale, known locally as the Monster, was a humpback whale that swam into the Firth of Tay of eastern Scotland in 1883. It was harpooned in a hunt, but escaped, and was found floating dead off Stonehaven a week later. It was towed into Dundee by a showman, John Woods, and exhibited on a train tour of Scotland and England.
  
  The Regius Professor of Anatomy at Aberdeen University, John Struthers dissected the whale, much of the time in public with a military band playing in the background, organised by Woods. The decomposing whale made Woods a great deal of money, and Struthers famous. (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...)
• 
  Cetacea is an infraorder that comprises the 94 species of whales, dolphins, and porpoises. It is divided into toothed whales (Odontoceti) and baleen whales (Mysticeti), which diverged from each other in the Eocene some 50 million years ago (mya). Cetaceans are descended from land-dwelling hoofed mammals, and the now extinct archaeocetes represent the several transitional phases from terrestrial to completely aquatic. Historically, cetaceans were thought to have descended from the wolf-like mesonychians, but cladistic analyses confirm their placement with even-toed ungulates in the order Cetartiodactyla.
  
  Whale populations were drastically reduced in the 20th century from intensive whaling, which lead to a moratorium on hunting by the International Whaling Commission in 1982. Smaller cetaceans are at risk of accidentally getting caught by fishing vessels using, namely, seine fishing, drift netting, or gill netting operations. (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...)
• 

  

  
  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...)
• 
  
  

  

  Rice's whale surfacing in the Gulf of Mexico

  
  Rice's whale (Balaenoptera ricei), also known as the Gulf of Mexico whale, is a species of baleen whale endemic to the northern Gulf of Mexico. Initially identified as a subpopulation of the Bryde's whale, genetic and skeletal studies found it to be a distinct species by 2021. In outward appearance, it is virtually identical to the Bryde's whale. Its body is streamlined and sleek, with a uniformly dark charcoal gray dorsal and pale to pinkish underside. A diagnostic feature often used by field scientists to distinguish Rice's whales from whales other than the Bryde's whale is the three prominent ridges that line the top of its head. The species can be distinguished from the Bryde's whale by the shape of the nasal bones, which have wider gaps due to a unique wrapping by the frontal bones, its unique vocal repertoire, and genetic differences.
  
  It is a medium-sized baleen whale that grows up to 12.65 meters (41.5 ft) in length and weighs up to 13.87–27.2 metric tons (13.65–26.77 long tons; 15.29–29.98 short tons). The Rice's whale inhabits a restricted stretch along the continental slope in the northeastern part of the Gulf of Mexico between depths of 150–410 meters (490–1,350 ft) off the coast of western Florida, although some whales have been sighted in the northwestern portions and the species may have inhabited a wider distribution throughout the Gulf in historical times. It does not migrate but remains within this area year-round. Little is known about the feeding behavior of Rice's whales, but data from a tagged individual revealed a diel vertical diving pattern, in which the whale spends most of the day feeding at or near the seafloor at depths of up to 271 meters (889 ft) and night at the surface. The whale's diet remains unknown, but lanternfish and hatchetfish are suspected prey. (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...)
• 
  
  

  

  Southern right whale breaching

  
  Right whales are three species of large baleen whales of the genus Eubalaena: the North Atlantic right whale (E. glacialis), the North Pacific right whale (E. japonica) and the Southern right whale (E. australis). They are classified in the family Balaenidae with the bowhead whale. Right whales have rotund bodies with arching rostrums, V-shaped blowholes and dark gray or black skin. The most distinguishing feature of a right whale is the rough patches of skin on its head, which appear white due to parasitism by whale lice. Right whales are typically 13–17 m (43–56 ft) long and weigh up to 100 short tons (91 t; 89 long tons) or more.
  
  All three species are migratory, moving seasonally to feed or give birth. The warm equatorial waters form a barrier that isolates the northern and southern species from one another although the southern species, at least, has been known to cross the equator. In the Northern Hemisphere, right whales tend to avoid open waters and stay close to peninsulas and bays and on continental shelves, as these areas offer greater shelter and an abundance of their preferred foods. In the Southern Hemisphere, right whales feed far offshore in summer, but a large portion of the population occur in near-shore waters in winter. Right whales feed mainly on copepods but also consume krill and pteropods. They may forage the surface, underwater or even the ocean bottom. During courtship, males gather into large groups to compete for a single female, suggesting that sperm competition is an important factor in mating behavior. Gestation tends to last a year, and calves are weaned at eight months old. (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...)

Selected picture

Humpback Whales often breach the waters surface.

Photo credit: Cornelia Oedekoven

Many whales are known to breach the waters surface. The act of leaping generates more power than any other act performed by a non-human animal.

Some whales, such as Sperm Whales, perform a breach by travelling vertically upwards from depth, and heading straight out of the water. Others, such as the Humpback Whale (pictured), travel close to the surface and parallel to it, and then jerk upwards at full speed to perform a breach. In a typical breach, as performed by a Humpback or Right Whale, the whale clears the water at an angle of about 30° to the horizontal.

More on whale behaviour

More did you know...

A Harbour Porpoise.

• ...that while the main predators of the Harbour Porpoise are Great white sharks and Orcas, Bottlenose Dolphins have been witnessed attacking and killing porpoises in response to a lessing food supply.
• ...Aboriginal whalers are permitted to hunt cetaceans, despite the IWC's memorandum on commercial hunting.
• ...the melon is an oval shaped oily, fatty lump of tissue found at the centre of the forehead of most dolphins and toothed whales, located between the blowhole and the end of the head.
• ...the Spinner Dolphin is so called because of its acrobatic displays in which they will spin longitudinally along their axis as they leap through the air.
• ...that the Tay Whale was a Humpback whale unlucky enough to be spotted near Dundee, Scotland, then the UK's premier whaling port, in early December, 1883.

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.

• 
  Humpback whales lunge-feeding in the course of bubble net fishing
• 
  A phylogenetic tree showing the relationships among cetacean families. (from Evolution of cetaceans)
• 
  Female right whale with calf
• 
  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)
• 
  Antarctic minke whale illustration
• 
  Bowhead whale illustration
• 
  A whale as depicted by Conrad Gessner, 1587, in his Historiae animalium (from Toothed whale)
• 
  Common minke whale illustration
• 
  Acrophyseter skull (from Evolution of cetaceans)
• 
  The remains of a North Atlantic right whale after it collided with a ship propeller
• 
  The nose of the whale is filled with a waxy substance that was widely used in candles, oil lamps, and lubricants (from Toothed whale)
• 
  Megalodon hunted Miocene baleen 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)
• 
  Archaeomysticetes, like Janjucetus, had teeth.
• 
  Pakicetus attocki skeleton (from Evolution of cetaceans)
• 
  Baleen whales vary considerably in size and shape, depending on their feeding behavior. (from Baleen whale)
• 
  Sei whale illustration
• 
  A protest against Japan's scientific whaling
• 
  Species of the infraorder Cetacea (from Evolution of cetaceans)
• 
  Biosonar by cetaceans (from Toothed whale)
• 
  Pacific white-sided dolphins porpoising (from Toothed whale)
• 
  Japanese scientific whaling on a pair of Antarctic minke whales (from Baleen whale)
• 
  Pygmy right whale illustration
• 
  Archaeocetes (like this Basilosaurus) had a heterodont dentition (from Evolution of cetaceans)
• 
  The heart of a blue whale with a person standing next to it
• 
  Orange whale lice on a right whale
• 
  Atlantic white-sided dolphin caught in a drive hunt in Hvalba on the Faroe Islands being taken away with a forklift (from Toothed whale)
• 
  Their eyes are relatively small for their size.
• 
  Gray whale illustration
• 
  World population graph of blue whales
• 
  Spectrogram of dolphin vocalizations. Whistles, whines, and clicks are visible as upside down V's, horizontal striations, and vertical lines, respectively. (from Toothed whale)
• 
  Accessory baleen plates taper off into small hairs (from Baleen whale)
• 
  An orca by the name of Ulises performing at SeaWorld, 2009 (from Toothed whale)
• 
  A humpback whale skeleton. Notice how the jaw is split into two.
• 
  Bryde's whale (rorqual) (from Baleen whale)
• 
  Eden's whale illustration
• 
  Blue whale illustration
• 
  Orca hunting a Weddell seal (from Toothed whale)
• 
  Restoration of Janjucetus hunderi (from Baleen whale)
• 
  Possible relationships between cetaceans and other ungulate groups. (from Evolution of cetaceans)
• 
  Anatomy of the bottlenose dolphin (from Toothed whale)
• 
  North Atlantic right whale illustration
• 
  Features of a sperm whale skeleton (from Toothed whale)
• 
  Humpback whale illustration
• 
  Fin whale illustration
• 
  South Atlantic right 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 of the first researchers to propose dolphin-assisted therapy for humans later renounced it?
• ... that the South Asian river dolphin is nearly blind and relies on echolocation for navigation?
• ... that one can swim with humpback whales in the Niue Nukutuluea Multiple-Use Marine Park?

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