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120-544: 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

240-415: A pinna and hair . Whales have an elongated head, especially baleen whales , due to the wide overhanging jaw. Bowhead whale plates can be 9 metres (30 ft) long. Their nostril(s) make up the blowhole , with one in toothed whales and two in baleen whales. The nostrils are located on top of the head above the eyes so that the rest of the body can remain submerged while surfacing for air. The back of

360-972: A better chance of preventing their prey from escaping, which is killed by being thrown around, rammed and jumped on. Arctic orcas may attack beluga whales and narwhals stuck in pools enclosed by sea ice, the former are also driven into shallower water where juveniles are grabbed. By contrast, orcas appear to be wary of pilot whales , which have been recorded to mob and chase them. Nevertheless, possible predation on long-finned pilot whales has been recorded in Iceland , and one study suggests short-finned pilot whales are among Caribbean Orcas' prey. Killer whales have been recorded attacking short-finned pilot whales in Peru as well. Orcas also prey on larger species such as sperm whales , grey whales , humpback whales and minke whales . On three separate occasions in 2019 orcas were recorded to have killed blue whales off

480-669: A cross between the bottlenose dolphin and the false killer whale) are kept at the Sea Life Park in Hawaii . Also two common/bottlenose hybrids reside in captivity: one at Discovery Cove and the other SeaWorld San Diego. In the early days, many bottlenose dolphins were wild-caught off the coast of Florida. Though the Marine Mammal Protection Act, established in 1972, allows an exception for the collection of dolphins for public display and research purposes when

600-448: A dead stranded animal in the Bay of Greifswald that had attracted a great deal of local interest. The orca is one of 35 species in the oceanic dolphin family , which first appeared about 11 million years ago. The orca lineage probably branched off shortly thereafter. Although it has morphological similarities with the false killer whale , the pygmy killer whale and the pilot whales ,

720-582: 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 . The International Union for Conservation of Nature assesses

840-501: A dramatic impact on prey species. However, whales in tropical areas appear to have more generalized diets due to lower food productivity. Orcas spend most of their time at shallow depths, but occasionally dive several hundred metres depending on their prey. Fish-eating orcas prey on around 30 species of fish. Some populations in the Norwegian and Greenland sea specialize in herring and follow that fish's autumnal migration to

960-601: A factor in the ability to produce sounds used in echolocation. Mysticeti, who don't have the ability to echolocate, possess general symmetry of the skull and facial region, while Odontoceti display a nasofacial asymmetry that is linked to their echolocating abilities. Differences in the level of asymmetry also seem to correlate with differences in the types of sounds produced. Mysticeti have exceptionally thin, wide basilar membranes in their cochleae without stiffening agents, making their ears adapted for processing low to infrasonic frequencies. The initial karyotype includes

1080-688: A form of animal abuse . Though cetaceans have been held in captivity in both North America and Europe by 1860— Boston Aquarial Gardens in 1859 and pairs of beluga whales in Barnum's American Museum in New York City museum— dolphins were first kept for paid entertainment in the Marine Studios dolphinarium founded in 1938 in St. Augustine , Florida . It was here that it was discovered that dolphins could be trained to perform tricks. Recognizing

1200-472: A form of animal abuse . The main arguments are that dolphins do not have enough freedom of movement in pools, regardless of pool size, (in the wild, dolphins swim hundreds of miles every day) and do not get enough stimulation. Dolphins often show repetitive behavior in captivity and sometimes become aggressive towards other animals or people. In some cases, the behavior of dolphins in captivity also results in their own death. The lifespan of dolphins in captivity

1320-439: A large melon and multiple, asymmetric air bags. River dolphins , unlike most other cetaceans, can turn their head 90°. Most other cetaceans have fused neck vertebrae and are unable to turn their head at all. The baleen of baleen whales consists of long, fibrous strands of keratin. Located in place of the teeth, it has the appearance of a huge fringe and is used to sieve the water for plankton and krill. Sperm whales have

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1440-584: A latitudinal basis to move between seasonal habitats. For example, the gray whale migrates 10,000 miles (16,000 km) round trip. The journey begins at winter birthing grounds in warm lagoons along Baja California, and traverses 5,000–7,000 miles (8,000–11,300 km) of coastline to summer feeding grounds in the Bering, Chuckchi and Beaufort seas off the coast of Alaska. Conscious breathing cetaceans sleep but cannot afford to be unconscious for long, because they may drown. While knowledge of sleep in wild cetaceans

1560-463: A long lifespan in captivity and a friendly appearance. Hundreds if not thousands of bottlenose dolphins live in captivity across the world, though exact numbers are hard to determine. Orcas are well known for their performances in shows, but the number of orcas kept in captivity is very small, especially when compared to the number of bottlenose dolphins, with only 44 captive orcas being held in aquaria as of 2012. The majority of orcas are located in

1680-523: A matriline is 5.5 animals. Because females can reach age 90, as many as four generations travel together. These matrilineal groups are highly stable. Individuals separate for only a few hours at a time, to mate or forage. With one exception, an orca named Luna , no permanent separation of an individual from a resident matriline has been recorded. Closely related matrilines form loose aggregations called pods, usually consisting of one to four matrilines. Unlike matrilines, pods may separate for weeks or months at

1800-541: A mistranslation of the Spanish "asesino de ballenas" (literally "whale killer"), reflecting their historical predation on whales. Since the 1960s, the use of "orca" instead of "killer whale" has steadily grown in common use. The genus name Orcinus means "of the kingdom of the dead", or "belonging to Orcus ". Ancient Romans originally used orca (pl. orcae ) for these animals, possibly borrowing Ancient Greek ὄρυξ ( óryx ), which referred (among other things) to

1920-540: A more limited repertoire. Individuals likely learn their dialect through contact with pod members. Family-specific calls have been observed more frequently in the days following a calf's birth, which may help the calf learn them. Dialects are probably an important means of maintaining group identity and cohesiveness. Similarity in dialects likely reflects the degree of relatedness between pods, with variation growing over time. When pods meet, dominant call types decrease and subset call types increase. The use of both call types

2040-558: A permit is obtained, bottlenose dolphins have not been captured in American waters since 1989. In most Western countries, breeding programs have been set up to provide the dolphinariums with new animals. To achieve a sufficient birth rate and to prevent inbreeding, artificial insemination (AI) is occasionally used. The use of AI also allows dolphinariums to increase the genetic diversity of their population without having to bring in any dolphins from other facilities. The trade of dolphins

2160-456: A protective circle around their calves with their flukes facing outwards, using them to repel the attackers. There is also evidence that humpback whales will defend against or mob orcas who are attacking either humpback calves or juveniles as well as members of other species. Prior to the advent of industrial whaling , great whales may have been the major food source for orcas. The introduction of modern whaling techniques may have aided orcas by

2280-537: A set of chromosomes from 2n = 44. They have four pairs of telocentric chromosomes (whose centromeres sit at one of the telomeres ), two to four pairs of subtelocentric and one or two large pairs of submetacentric chromosomes. The remaining chromosomes are metacentric—the centromere is approximately in the middle—and are rather small. All cetaceans have chromosomes 2n = 44, except the sperm whales and pygmy sperm whales , which have 2n = 42. Cetaceans are found in many aquatic habitats. While many marine species, such as

2400-742: A small group, herring are often caught using carousel feeding : the orcas force the herring into a tight ball by releasing bursts of bubbles or flashing their white undersides. They then slap the ball with their tail flukes, stunning or killing up to 15 fish at a time, then eating them one by one. Carousel feeding has been documented only in the Norwegian orca population, as well as some oceanic dolphin species. In New Zealand, sharks and rays appear to be important prey, including eagle rays , long-tail and short-tail stingrays , common threshers , smooth hammerheads , blue sharks , basking sharks , and shortfin makos . With sharks, orcas may herd them to

2520-760: A specific body of water. The southern right whale dolphin and the hourglass dolphin live only in the Southern Ocean . The narwhal and the beluga live only in the Arctic Ocean. Sowerby's beaked whale and the Clymene dolphin exist only in the Atlantic and the Pacific white-sided dolphin and the northern straight dolphin live only in the North Pacific. Cosmopolitan species may be found in

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2640-549: A study of cytochrome b gene sequences indicates that its closest extant relatives are the snubfin dolphins of the genus Orcaella . However, a more recent (2018) study places the orca as a sister taxon to the Lissodelphininae, a clade that includes Lagenorhynchus and Cephalorhynchus . In contrast, a 2019 phylogenetic study found the orca to be the second most basal member of the Delphinidae, with only

2760-426: A terrestrial mammal breathing out on a cold day, a small cloud of 'steam' appears. This is called the 'spout' and varies across species in shape, angle and height. Species can be identified at a distance using this characteristic. The structure of the respiratory and circulatory systems is of particular importance for the life of marine mammals . The oxygen balance is effective. Each breath can replace up to 90% of

2880-439: A threat to humans, and no fatal attack has ever been documented in their natural habitat. There have been cases of captive orcas killing or injuring their handlers at marine theme parks. Orcas also feature strongly in the mythologies of indigenous cultures, and their reputation in different cultures ranges from being the souls of humans to merciless killers. Orcas, despite being dolphins, are commonly called "killer whales" due to

3000-798: A time. DNA testing indicates resident males nearly always mate with females from other pods. Clans, the next level of resident social structure, are composed of pods with similar dialects, and common but older maternal heritage. Clan ranges overlap, mingling pods from different clans. The highest association layer is the community, which consists of pods that regularly associate with each other but share no maternal relations or dialects. Transient pods are smaller than resident pods, typically consisting of an adult female and one or two of her offspring. Males typically maintain stronger relationships with their mothers than other females. These bonds can extend well into adulthood. Unlike residents, extended or permanent separation of transient offspring from natal matrilines

3120-540: A variety of techniques designed to stop them, such as the use of unbaited lines as decoys. Once, fishermen placed their boats several miles apart, taking turns retrieving small amounts of their catch, in the hope that the whales would not have enough time to move between boats to steal the catch as it was being retrieved. The tactic worked initially, but the orcas figured it out quickly and split into groups. In other anecdotes, researchers describe incidents in which wild orcas playfully tease humans by repeatedly moving objects

3240-458: A weight of over 10 t (9.8 long tons; 11 short tons). Calves at birth weigh about 180 kg (400 lb) and are about 2.4 m (7 ft 10 in) long. The skeleton of the orca is typical for an oceanic dolphin, but more robust. With their distinctive pigmentation, adult orcas are seldom confused with any other species. When seen from a distance, juveniles can be confused with false killer whales or Risso's dolphins . The orca

3360-416: A whale species, perhaps a narwhal . As part of the family Delphinidae , the species is more closely related to other oceanic dolphins than to other whales. They are sometimes referred to as "blackfish", a name also used for other whale species. "Grampus" is a former name for the species, but is now seldom used. This meaning of "grampus" should not be confused with the genus Grampus , whose only member

3480-430: Is Risso's dolphin . Orcinus orca is the only recognized extant species in the genus Orcinus , and one of many animal species originally described by Carl Linnaeus in his landmark 1758 10th edition of Systema Naturae . Konrad Gessner wrote the first scientific description of an orca in his Piscium & aquatilium animantium natura of 1558, part of the larger Historia animalium , based on examination of

3600-654: Is bicornuate . Cetacean eyes are set on the sides rather than the front of the head. This means only species 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. Odontocetes have little to no ability to taste or smell, while mysticetes are believed to have some ability to smell because of their reduced, but functional olfactory system . Cetaceans are known to possess excellent hearing. At least one species,

3720-681: Is a behaviour in which a whale holds its head above water to view its surroundings. Resident orcas swim alongside porpoises and other dolphins . Orcas will engage in surplus killing , that is, killing that is not designed to be for food. As an example, a BBC film crew witnessed orca in British Columbia playing with a male Steller sea lion to exhaustion, but not eating it. Orcas are notable for their complex societies. Only elephants and higher primates live in comparably complex social structures . Due to orcas' complex social bonds, many marine experts have concerns about how humane it

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3840-447: 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

3960-525: Is another subject of debate. Research has shown that there is no significant difference between wild and captive survival rates for bottlenose dolphins. This does not, however, reflect a global state of affairs: for example, bottlenose dolphins in captive facilities in Jamaica suffer from extremely high mortality rates. Some scientists suggest that the "unusually high" intelligence of dolphins means that they should be recognized as "non-human persons". In 2013,

4080-871: Is called biphonation. The increased subset call types may be the distinguishing factor between pods and inter-pod relations. Dialects also distinguish types. Resident dialects contain seven to 17 (mean = 11) distinctive call types. All members of the North American west coast transient community express the same basic dialect, although minor regional variation in call types is evident. Preliminary research indicates offshore orcas have group-specific dialects unlike those of residents and transients. Norwegian and Icelandic herring -eating orcas appear to have different vocalizations for activities like hunting. A population that live in McMurdo Sound , Antarctica have 28 complex burst-pulse and whistle calls. Orcas have

4200-605: Is common, with juveniles and adults of both sexes participating. Some males become "rovers" and do not form long-term associations, occasionally joining groups that contain reproductive females. As in resident clans, transient community members share an acoustic repertoire, although regional differences in vocalizations have been noted. As with residents and transients, the lifestyle of these whales appears to reflect their diet; fish-eating orcas off Norway have resident-like social structures, while mammal-eating orcas in Argentina and

4320-515: Is considered to be functionally extinct due to human activity. The two parvorders, baleen whales (Mysticeti) and toothed whales (Odontoceti), are thought to have diverged around thirty-four million years ago. Baleen whales have bristles made of keratin instead of teeth . The bristles filter krill and other small invertebrates from seawater. Grey whales feed on bottom-dwelling mollusks. Rorqual family (balaenopterids) use throat pleats to expand their mouths to take in food and sieve out

4440-591: Is difficult to estimate, but they clearly prefer higher latitudes and coastal areas over pelagic environments. Areas which serve as major study sites for the species include the coasts of Iceland , Norway, the Valdés Peninsula of Argentina, the Crozet Islands , New Zealand and parts of the west coast of North America, from California to Alaska . Systematic surveys indicate the highest densities of orcas (>0.40 individuals per 100 km ) in

4560-430: Is home to elongated spindle neurons that, prior to 2019, were known only in hominids . In humans, these cells are thought to be involved in social conduct, emotions, judgment and theory of mind. Cetacean spindle neurons are found in areas of the brain homologous to where they are found in humans, suggesting they perform a similar function. The cetacean skeleton is largely made up of cortical bone , which stabilizes

4680-817: Is likely to be the result of scavenging remains dumped by whalers. One orca was also attacked by its companions after being shot. Although resident orcas have never been observed to eat other marine mammals, they occasionally harass and kill porpoises and seals for no apparent reason. Some dolphins recognize resident orcas as harmless and remain in the same area. Orcas do consume seabirds but are more likely to kill and leave them uneaten. Penguin species recorded as prey in Antarctic and sub-Antarctic waters include gentoo penguins , chinstrap penguins , king penguins and rockhopper penguins . Orcas in many areas may prey on cormorants and gulls . A captive orca at Marineland of Canada discovered it could regurgitate fish onto

4800-433: Is limited, toothed cetaceans in captivity have been recorded to exhibit unihemispheric slow-wave sleep (USWS), which means they sleep with one side of their brain at a time, so that they may swim, breathe consciously and avoid both predators and social contact during their period of rest. A 2008 study found that sperm whales sleep in vertical postures just under the surface in passive shallow 'drift-dives', generally during

4920-442: Is mainly limited to surfacing activities and milling (slow swimming with no apparent direction) after a kill. All members of a resident pod use similar calls, known collectively as a dialect . Dialects are composed of specific numbers and types of discrete, repetitive calls. They are complex and stable over time. Call patterns and structure are distinctive within matrilines. Newborns produce calls similar to their mothers, but have

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5040-427: Is mostly black but with sharply bordered white areas. The entire lower jaw is white and from here, the colouration stretches across the underside to the genital area; narrowing and expanding some, and extending into lateral flank patches close to the end. The tail fluke (fin) is also white on the underside, while the eyes have white oval-shaped patches behind and above them, and a grey or white "saddle patch" exists behind

5160-843: Is regulated by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (also known as the Washington Convention or CITES ). Endangered dolphin species are included in CITES' Appendix I, in which case trade is permitted only in exceptional circumstances. Species considered not to be threatened with extinction are included in Appendix II, in which case trade "must be controlled in order to avoid utilization incompatible with their survival". Most cetacean species traded for display in captivity to

5280-424: Is so well-adapted for both air and water that some blind specimens can survive. Some species, such as sperm whales, are well adapted for diving to great depths. Several species of toothed whales show sexual dimorphism , in which the males differ from the females, usually for purposes of sexual display or aggression. Cetacean bodies are generally similar to those of fish, which can be attributed to their lifestyle and

5400-759: Is swallowed whole. Teeth are shaped like cones (dolphins and sperm whales), spades ( porpoises ), pegs ( belugas ), tusks ( narwhals ) or variable (beaked whale males). Female beaked whales' teeth are hidden in the gums and are not visible, and most male beaked whales have only two short tusks. Narwhals have vestigial teeth other than their tusk, which is present on males and 15% of females and has millions of nerves to sense water temperature, pressure and salinity. A few toothed whales, such as some orcas , feed on mammals, such as pinnipeds and other whales. Toothed whales have well-developed senses – their eyesight and hearing are adapted for both air and water, and they have advanced sonar capabilities using their melon . Their hearing

5520-444: 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

5640-426: Is to keep them in captivity . Resident orcas in the eastern North Pacific live in particularly complex and stable social groups. Unlike any other known mammal social structure, resident whales live with their mothers for their entire lives. These family groups are based on matrilines consisting of the eldest female (matriarch) and her sons and daughters, and the descendants of her daughters, etc. The average size of

5760-412: Is vital for deep diving, since beyond a depth around 100 m (330 ft), the lung tissue is almost completely compressed by the water pressure. The stomach consists of three chambers. The first region is formed by a loose gland and a muscular forestomach (missing in beaked whales); this is followed by the main stomach and the pylorus . Both are equipped with glands to help digestion. A bowel adjoins

5880-614: The Acuario Nacional de Cuba . In recent years, the Solomon Islands have also allowed the collection and export of dolphins for public display facilities. A 2005 law banned the export of dolphins, however, this ban was seemingly overturned in 2007 when some 28 dolphins were shipped to Dubai . Many animal welfare groups such as the World Animal Protection consider keeping dolphins in captivity to be

6000-459: The Amazon river dolphin . The collarbone is completely absent. Cetaceans have a cartilaginous fluke at the end of their tails that is used for propulsion. The fluke is set horizontally on the body and used with vertical movements, unlike fish and ichthyosaurs, which have vertical tails which move horizontally. Cetaceans have powerful hearts. Blood oxygen is distributed effectively throughout

6120-492: The Atlantic white-sided dolphin ( Leucopleurus acutus ) being more basal. The three to five types of orcas may be distinct enough to be considered different races , subspecies , or possibly even species (see Species problem ). The IUCN reported in 2008, "The taxonomy of this genus is clearly in need of review, and it is likely that O. orca will be split into a number of different species or at least subspecies over

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6240-540: The Crozet Islands behave more like transients. Orcas of the same sex and age group may engage in physical contact and synchronous surfacing. These behaviours do not occur randomly among individuals in a pod, providing evidence of "friendships". Like all cetaceans , orcas depend heavily on underwater sound for orientation, feeding, and communication. They produce three categories of sounds: clicks, whistles, and pulsed calls. Clicks are believed to be used primarily for navigation and discriminating prey and other objects in

6360-510: The Crozet Islands , mothers push their calves onto the beach, waiting to pull the youngster back if needed. In March 2023, a female orca was spotted with a newborn pilot whale in Snæfellsnes . People who have interacted closely with orcas offer numerous anecdotes demonstrating the whales' curiosity, playfulness, and ability to solve problems. Alaskan orcas have not only learned how to steal fish from longlines , but have also overcome

6480-400: The Crozet Islands , orcas feed on South American sea lions and southern elephant seals in shallow water, even beaching temporarily to grab prey before wriggling back to the sea. Beaching, usually fatal to cetaceans, is not an instinctive behaviour, and can require years of practice for the young. Orcas can then release the animal near juvenile whales, allowing the younger whales to practice

6600-511: The EU . Japan , Mexico and the United States are also home to a relatively large number of dolphinariums. The water in the pools has to be constantly filtered to keep it clean for the dolphins and the temperature and composition of the water has to be controlled to match the conditions dolphins experience in the wild. In the absence of a common international regulation, guidelines regarding

6720-587: The Faroe Islands . In the Antarctic, orcas range up to the edge of the pack ice and are believed to venture into the denser pack ice, finding open leads much like beluga whales in the Arctic. However, orcas are merely seasonal visitors to Arctic waters, and do not approach the pack ice in the summer. With the rapid Arctic sea ice decline in the Hudson Strait , their range now extends deep into

6840-783: The Indian Ministry of Environment and Forests prohibited the captivity of dolphins on these grounds, finding it "morally unacceptable to keep them captive for entertainment purpose". In 2019, the Ending the Captivity of Whales and Dolphins Act became law in Canada. Two facilities would be affected, Marineland of Canada and the Vancouver Aquarium . When passed in June 2019, Marineland was reported to have 61 cetaceans, while

6960-532: The beaked whale family, several species of the porpoise family, orcas, pilot whales , eastern spinner dolphins and northern right whale dolphins show this characteristic. Males in these species developed external features absent in females that are advantageous in combat or display. For example, male sperm whales are up to 63% percent larger than females, and many beaked whales possess tusks used in competition among males. Hind legs are not present in cetaceans, nor are any other external body attachments such as

7080-664: The blue whale , the humpback whale and the orca , have a distribution area that includes nearly the entire ocean, some species occur only locally or in broken populations. These include the vaquita , which inhabits a small part of the Gulf of California and Hector's dolphin , which lives in some coastal waters in New Zealand. Most river dolphin species live exclusively in fresh water. Many species inhabit specific latitudes, often in tropical or subtropical waters, such as Bryde's whale or Risso's dolphin . Others are found only in

7200-404: The melon as a head buckle. This is filled with air sacs and fat that aid in buoyancy and biosonar . The sperm whale has a particularly pronounced melon; this is called the spermaceti organ and contains the eponymous spermaceti , hence the name "sperm whale". Even the long tusk of the narwhal is a vice-formed tooth. In many toothed whales, the depression in their skull is due to the formation of

7320-477: The nominate subspecies . Four types have been documented in the Antarctic , Types A–D. Two dwarf species, named Orcinus nanus and Orcinus glacialis , were described during the 1980s by Soviet researchers, but most cetacean researchers are skeptical about their status. Complete mitochondrial sequencing indicates the two Antarctic groups (types B and C) should be recognized as distinct species, as should

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7440-404: 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

7560-433: The tucuxi or Guiana dolphin, is able to use electroreception to sense prey. The external ear has lost the pinna (visible ear), but still retains a narrow ear canal . The three small bones or ossicles that transmit sound within each ear are dense and compact , and differently shaped from those of land mammals. The semicircular canals are much smaller relative to body size than in other mammals. A bony structure of

7680-692: The 1972 Marine Mammal Protection Act in the United States , combined with a more critical view on animal welfare, forced many dolphinariums around the world to close. A prominent example is the United Kingdom ; in the early 1970s there were at least 36 dolphinariums and traveling dolphin shows, however, the last dolphinarium closed its doors in 1993. The last dolphinarium in Hungary was closed in 1992. In 2005 both Chile and Costa Rica prohibited keeping cetaceans captive. However, around 60 dolphinariums currently exist across Europe, of which 34 are within

7800-513: The 1990s was controversially attributed by some scientists to orca predation, although with no direct evidence. The decline of sea otters followed a decline in seal populations, which in turn may be substitutes for their original prey, now decimated by industrial whaling. Orcas have been observed preying on terrestrial mammals , such as moose swimming between islands off the northwest coast of North America. Orca cannibalism has also been reported based on analysis of stomach contents, but this

7920-401: The 2000s that 2,321 orcas were in the seas around Japan. Orcas are apex predators , meaning that they themselves have no natural predators. They are sometimes called "wolves of the sea", because they hunt in groups like wolf packs. Orcas hunt varied prey including fish, cephalopods , mammals, seabirds , and sea turtles . Different populations or ecotypes may specialize, and some can have

8040-635: The American states California, New York, and South Carolina. Other countries have laws so restrictive that is virtually impossible to keep cetaceans in captivity: Brazil, Luxembourg, Nicaragua, Norway, and the United Kingdom. France tried to ban keeping or breeding cetaceans in captivity in 2017, but the ban was overturned on technical grounds by the Conseil d'État in 2018. On 29 September 2020, Environment Minister Barbara Pompili announced that France's three remaining dolphinariums would be closed within

8160-706: The North Pacific transients, leaving the others as subspecies pending additional data. A 2019 study of Type D orcas also found them to be distinct from other populations and possibly even a unique species. Orcas are the largest extant members of the dolphin family. Males typically range from 6 to 8 m (20 to 26 ft) long and weigh in excess of 6 t (5.9 long tons; 6.6 short tons). Females are smaller, generally ranging from 5 to 7 m (16 to 23 ft) and weighing about 3 to 4 t (3.0 to 3.9 long tons; 3.3 to 4.4 short tons). Orcas may attain larger sizes as males have been recorded at 9.8 m (32 ft) and females at 8.5 m (28 ft). Large males can reach

8280-489: The Norwegian coast. Salmon account for 96% of northeast Pacific residents' diet, including 65% of large, fatty Chinook . Chum salmon are also eaten, but smaller sockeye and pink salmon are not a significant food item. Depletion of specific prey species in an area is, therefore, cause for concern for local populations, despite the high diversity of prey. On average, an orca eats 227 kilograms (500 lb) each day. While salmon are usually hunted by an individual whale or

8400-675: The Pacific, Atlantic and Indian Oceans. However, northern and southern populations become genetically separated over time. In some species, this separation leads eventually to a divergence of the species, such as produced the southern right whale , North Pacific right whale and North Atlantic right whale . Migratory species' reproductive sites often lie in the tropics and their feeding grounds in polar regions. Thirty-two species are found in European waters, including twenty-five toothed and seven baleen species. Many species of whales migrate on

8520-591: The Vancouver Aquarium had just one dolphin remaining. The law has a grandfather clause , permitting those cetaceans already in captivity to remain where they are, but breeding and further acquisition of cetaceans is prohibited, subject to limited exceptions. According to animal rights organizations that monitor the subject, the following jurisdictions have full or partial bans on keeping dolphins in captivity: Bolivia, Canada, Costa Rica, Croatia, Cyprus, Greece, Hungary, India, Slovenia, Switzerland, Turkey, and

8640-470: The age of 10 and reach peak fertility around 20, experiencing periods of polyestrous cycling separated by non-cycling periods of three to 16 months. Females can often breed until age 40, followed by a rapid decrease in fertility. Orcas are among the few animals that undergo menopause and live for decades after they have finished breeding. The lifespans of wild females average 50 to 80 years. Some are claimed to have lived substantially longer: Granny (J2)

8760-402: The amount of brain mass available for cognitive tasks. Allometric analysis of the relationship between mammalian brain mass (weight) and body mass for different species of mammals shows that larger species generally have larger brains. However, this increase is not fully proportional. Typically the brain mass only increases in proportion to somewhere between the two-thirds power (or the square of

8880-522: The animal in the water. For this reason, the usual terrestrial compact bones, which are finely woven cancellous bone , are replaced with lighter and more elastic material. In many places, bone elements are replaced by cartilage and even fat, thereby improving their hydrostatic qualities. The ear and the muzzle contain a bone shape that is exclusive to cetaceans with a high density, resembling porcelain . This conducts sound better than other bones, thus aiding biosonar . The number of vertebrae that make up

9000-439: The body wall. The stable lumbar and tail include the other vertebrae. Below the caudal vertebrae is the chevron bone . The front limbs are paddle-shaped with shortened arms and elongated finger bones, to support movement. They are connected by cartilage. The second and third fingers display a proliferation of the finger members, a so-called hyperphalangy. The shoulder joint is the only functional joint in all cetaceans except for

9120-416: The body. They are warm-blooded, i.e., they hold a nearly constant body temperature. Cetaceans have lungs, meaning they breathe air. An individual can last without a breath from a few minutes to over two hours depending on the species. Cetacea are deliberate breathers who must be awake to inhale and exhale. When stale air, warmed from the lungs, is exhaled, it condenses as it meets colder external air. As with

9240-403: The brain folds around the insula and expands more laterally than in terrestrial mammals. As a result, the cetacean prefrontal cortex (compared to that in humans) rather than frontal is laterally positioned. Brain size was previously considered a major indicator of intelligence . Since most of the brain is used for maintaining bodily functions, greater ratios of brain to body mass may increase

9360-556: The clade Whippomorpha . Cetaceans have been extensively hunted for their meat, blubber and oil by commercial operations. Although the International Whaling Commission has agreed on putting a halt to commercial whaling, whale hunting is still going on, either under IWC quotas to assist the subsistence of Arctic native people or in the name of scientific research, although a large spectrum of non-lethal methods are now available to study marine mammals in

9480-542: The cube root) and the three-quarters power (or the cube of the fourth root) of the body mass. m brain ∝ ( m body ) where k is between two-thirds and three-quarters. Thus if Species B is twice the size of Species A, its brain size will typically be somewhere between 60% and 70% higher. Comparison of a particular animal's brain size with the expected brain size based on such an analysis provides an encephalization quotient that can be used as an indication of animal intelligence. The neocortex of many cetaceans

9600-587: The day, during which whales do not respond to passing vessels unless they are in contact, leading to the suggestion that whales possibly sleep during such dives. Orca 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

9720-474: The decline of these as well. Other marine mammal prey includes seal species such as harbour seals , elephant seals , California sea lions , Steller sea lions , South American sea lions and walruses . Often, to avoid injury, orcas disable their prey before killing and eating it. This may involve throwing it in the air, slapping it with their tails, ramming it, or breaching and landing on it. In steeply banked beaches off Península Valdés , Argentina, and

9840-472: The difficult capture technique on the now-weakened prey. In the Antarctic, type B orcas hunt Weddell seals and other prey by "wave-hunting". They "spy-hop" to locate them on resting on ice floes, and then swim in groups to create waves that wash over the floe. This washes the prey into the water, where other orcas lie in wait. In the Aleutian Islands , a decline in sea otter populations in

9960-648: The dorsal fin and across the back. Males and females also have different patterns of black and white skin in their genital areas. In newborns, the white areas are yellow or orange coloured. Antarctic orcas may have pale grey to nearly white backs. Some Antarctic orcas are brown and yellow due to diatoms in the water. Both albino and melanistic orcas have been documented. Orca pectoral fins are large and rounded, resembling paddles, with those of males significantly larger than those of females. Dorsal fins also exhibit sexual dimorphism , with those of males about 1.8 m (5 ft 11 in) high, more than twice

10080-492: The dorsal fin and the pattern of white or grey in the saddle patch are unique. Published directories contain identifying photographs and names for hundreds of North Pacific animals. Photographic identification has enabled the local population of orcas to be counted each year rather than estimated, and has enabled great insight into life cycles and social structures. Orcas are found in all oceans and most seas. Due to their enormous range , numbers, and density, relative distribution

10200-527: The elevation of Eastern North American resident and transient orcas as distinct species, O. ater and O. rectipinnus respectively. The Society for Marine Mammalogy declined to recognize the two species, citing uncertainty as to whether the types constituted unique species or subspecies. "Pending a more complete global review and revision", the Society provisionally recognized them as subspecies Orcinus orca ater and O. o. rectipinnus , with O. o. orca as

10320-530: The fin are for stabilization and steering in the water. The male genitals and the mammary glands of females are sunken into the body. The male genitals are attached to a vestigial pelvis . The body is wrapped in a thick layer of fat, known as blubber . This provides thermal insulation and gives cetaceans their smooth, streamlined body shape. In larger species, it can reach a thickness up to one-half meter (1.6 feet). Sexual dimorphism evolved in many toothed whales. Sperm whales, narwhals , many members of

10440-403: 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

10560-405: The habitat conditions. Their body is well-adapted to their habitat, although they share essential characteristics with other higher mammals ( Eutheria ). They have a streamlined shape, and their forelimbs are flippers . Almost all have a dorsal fin on their backs, but this can take on many forms, depending on the species. A few species, such as the beluga whale , lack them. Both the flipper and

10680-526: The humans are trying to reach, or suddenly start to toss around a chunk of ice after a human throws a snowball. The orca's use of dialects and the passing of other learned behaviours from generation to generation have been described as a form of animal culture . The complex and stable vocal and behavioural cultures of sympatric groups of killer whales ( Orcinus orca ) appear to have no parallel outside humans and represent an independent evolution of cultural faculties. Female orcas begin to mature at around

10800-434: The largest brain mass of any animal on Earth, averaging 8,000 cm (490 in ) and 7.8 kg (17 lb) in mature males. The brain to body mass ratio in some odontocetes, such as belugas and narwhals, is second only to humans. In some whales, however, it is less than half that of humans: 0.9% versus 2.1%. In cetaceans, evolution in the water has caused changes to the head that have modified brain shape such that

10920-603: The liver of sharks. In one case a single orca was observed killing and eating a great white shark on its own. Orcas are sophisticated and effective predators of marine mammals . They are recorded to prey on other cetacean species, usually smaller dolphins and porpoises such as common dolphins , bottlenose dolphins , Pacific white-sided dolphins , dusky dolphins , harbour porpoises and Dall's porpoises . While hunting these species, orcas usually have to chase them to exhaustion. For highly social species, orca pods try to separate an individual from its group. Larger groups have

11040-442: The lower teeth when the mouth is closed. The firm middle and back teeth hold prey in place, while the front teeth are inclined slightly forward and outward to protect them from powerful jerking movements. Orcas have good eyesight above and below the water, excellent hearing, and a good sense of touch. They have exceptionally sophisticated echolocation abilities, detecting the location and characteristics of prey and other objects in

11160-422: 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

11280-469: The middle and inner ear, the auditory bulla , is composed of two compact and dense bones (the periotic and tympanic). It is housed in a cavity in the middle ear; in the Odontoceti (apart from in the physeterids , this cavity is filled with dense foam and completely surrounds the bulla, which is connected to the skull only by ligaments. This may isolate the ear from sounds transmitted through the bones of

11400-639: The minimum size of the pools vary between countries. To give an indication of pool sizes, the European Association for Aquatic Mammals recommends that a pool for five dolphins should have a surface area of 275 m (2,960 sq ft) plus an additional 75 m (810 sq ft) for every additional animal, have a depth of 3.5 m (11 ft) and have a water volume of at least 1,000 m (35,000 cu ft) with an additional 200 m (7,100 cu ft) for every additional animal. If two of these three conditions are met, and

11520-690: The next 7 to 10 years, and no new dolphinariums could be opened, and no new marine mammals could be bred or imported. A month earlier on 31 August 2020, the Brussels Capital Region (which has no dolphinaria) announced it was working on a ban on any future creation of dolphinariums to safeguard the welfare of any marine mammals that might end up being kept within its territory. Cetaceans ( see text for families) Cetacea ( / s ɪ ˈ t eɪ ʃ ə / ; from Latin cetus  ' whale ', from Ancient Greek κῆτος ( kêtos )  ' huge fish , sea monster ')

11640-583: The next few years." Although large variation in the ecological distinctiveness of different orca groups complicate simple differentiation into types, research off the west coast of North America has identified fish-eating "residents", mammal-eating "transients" and "offshores". Other populations have not been as well studied, although specialized fish and mammal eating orcas have been distinguished elsewhere. Mammal-eating orcas in different regions were long thought likely to be closely related, but genetic testing has refuted this hypothesis. A 2024 study supported

11760-472: The northeast Atlantic around the Norwegian coast, in the north Pacific along the Aleutian Islands , the Gulf of Alaska and in the Southern Ocean off much of the coast of Antarctica . They are considered "common" (0.20–0.40 individuals per 100 km ) in the eastern Pacific along the coasts of British Columbia , Washington and Oregon , in the North Atlantic Ocean around Iceland and

11880-760: The northwest Atlantic. Occasionally, orcas swim into freshwater rivers. They have been documented 100 mi (160 km) up the Columbia River in the United States. They have also been found in the Fraser River in Canada and the Horikawa River in Japan. Migration patterns are poorly understood. Each summer, the same individuals appear off the coasts of British Columbia and Washington. Despite decades of research, where these animals go for

12000-451: The orca's conservation status as data deficient because of the likelihood that two or more orca types are separate species . Some local populations are considered threatened or endangered due to prey depletion, habitat loss , pollution (by PCBs ), capture for marine mammal parks , and conflicts with human fisheries . In late 2005, the southern resident orcas were placed on the U.S. Endangered Species list . Orcas are not usually

12120-609: The public or for use in swimming with dolphins and other interaction programs are listed on Appendix II. However, the dolphin trade still continues. A live bottlenose dolphin is estimated to be worth between a few thousand to several tens of thousands of US dollars , depending on age, condition and prior training. Captures are reported to be on the rise in the South Pacific and the Caribbean , Cuba has also been an exporter of dolphins in recent years, this being organized by

12240-422: The rest of the year remains unknown. Transient pods have been sighted from southern Alaska to central California. Worldwide population estimates are uncertain, but recent consensus suggests a minimum of 50,000 (2006). Local estimates include roughly 25,000 in the Antarctic, 8,500 in the tropical Pacific, 2,250–2,700 off the cooler northeast Pacific and 500–1,500 off Norway. Japan's Fisheries Agency estimated in

12360-524: The second-heaviest brains among marine mammals (after sperm whales , which have the largest brain of any animal). Orcas have more gray matter and more cortical neurons than any mammal, including humans. They can be trained in captivity and are often described as intelligent, although defining and measuring "intelligence" is difficult in a species whose environment and behavioural strategies are very different from those of humans. Orcas imitate others, and seem to deliberately teach skills to their kin. Off

12480-400: The size of the female's, with the male's fin more like an elongated isosceles triangle , whereas the female's is more curved. In the skull, adult males have longer lower jaws than females, as well as larger occipital crests . The snout is blunt and lacks the beak of other species. The orca's teeth are very strong, and its jaws exert a powerful grip; the upper teeth fall into the gaps between

12600-426: The skull is significantly shortened and deformed. By shifting the nostrils to the top of the head, the nasal passages extend perpendicularly through the skull. The teeth or baleen in the upper jaw sit exclusively on the maxilla . The braincase is concentrated through the nasal passage to the front and is correspondingly higher, with individual cranial bones that overlap. In toothed whales, connective tissue exists in

12720-908: The skull, something that also happens in bats . Cetaceans use sound to communicate , using groans, moans, whistles, clicks or the 'singing' of the humpback whale. Odontoceti are generally capable of echolocation . They can discern the size, shape, surface characteristics, distance and movement of an object. They can search for, chase and catch fast-swimming prey in total darkness. Most Odontoceti can distinguish between prey and nonprey (such as humans or boats); captive Odontoceti can be trained to distinguish between, for example, balls of different sizes or shapes. Echolocation clicks also contain characteristic details unique to each animal, which may suggest that toothed whales can discern between their own click and that of others. While differences in ear structure associated with echolocating abilities are found amongst Cetacea, cranial asymmetry has also been found to be

12840-404: The sound of exploding harpoons indicating the availability of prey to scavenge, and compressed air inflation of whale carcasses causing them to float, thus exposing them to scavenging. However, the devastation of great whale populations by unfettered whaling has possibly reduced their availability for orcas, and caused them to expand their consumption of smaller marine mammals, thus contributing to

12960-405: The south coast of Western Australia, including an estimated 18–22-meter (59–72 ft) individual. Large whales require much effort and coordination to kill and orcas often target calves. A hunt begins with a chase followed by a violent attack on the exhausted prey. Large whales often show signs of orca attack via tooth rake marks. Pods of female sperm whales sometimes protect themselves by forming

13080-457: The spine varies by species, ranging from forty to ninety-three. The cervical spine , found in all mammals, consists of seven vertebrae which, however, are reduced or fused. This fusion provides stability during swimming at the expense of mobility. The fins are carried by the thoracic vertebrae , ranging from nine to seventeen individual vertebrae. The sternum is cartilaginous. The last two to three pairs of ribs are not connected and hang freely in

13200-500: The stomachs, whose individual sections can only be distinguished histologically . The liver is large and separate from the gall bladder . The kidneys are long and flattened. The salt concentration in cetacean blood is lower than that in seawater, requiring kidneys to excrete salt. This allows the animals to drink seawater. The urinary bladder is proportionally smaller in cetaceans than in land mammals. The testes are located internally, without an external scrotum . The uterus

13320-482: The success of Marine Studios, more dolphinariums began keeping dolphins for entertainment. In the 1960s, keeping dolphins in zoos and aquariums for entertainment purposes increased in popularity after the 1963 Flipper movie and subsequent Flipper television series . In 1966, the first dolphin was exported to Europe . In these early days, dolphinariums could grow quickly due to a lack of legislation and lack of organised animal welfare . New legislation, most notably

13440-481: The surface and strike them with their tail flukes, while bottom-dwelling rays are cornered, pinned to the ground and taken to the surface. In other parts of the world, orcas have preyed on broadnose sevengill sharks , small whale sharks and even great white sharks . Competition between orcas and white sharks is probable in regions where their diets overlap. The arrival of orcas in an area can cause white sharks to flee and forage elsewhere. Orcas appear to target

13560-458: The surface, attracting sea gulls, and then eat the birds. Four others then learned to copy the behaviour. Day-to-day orca behaviour generally consists of foraging , travelling, resting and socializing. Orcas frequently engage in surface behaviour such as breaching (jumping completely out of the water) and tail-slapping. These activities may have a variety of purposes, such as courtship, communication, dislodging parasites , or play . Spyhopping

13680-483: The surrounding environment, but are also commonly heard during social interactions. Northeast Pacific resident groups tend to be much more vocal than transient groups in the same waters. Residents feed primarily on Chinook and chum salmon, which are insensitive to orca calls (inferred from the audiogram of Atlantic salmon). In contrast, the marine mammal prey of transients hear whale calls well and thus transients are typically silent. Vocal behaviour in these whales

13800-531: The third is not more than 10% below standard, the EAAM considers the pool size to be acceptable. Various species of dolphins are kept in captivity as well as several other small whale species such as harbour porpoises , finless porpoises and belugas , though in those cases the word dolphinarium may not be fitting as these are not true dolphins. Bottlenose dolphins are the most common species of dolphins kept in dolphinariums as they are relatively easy to train, have

13920-427: The total lung volume. For land mammals, in comparison, this value is usually about 15%. During inhalation, about twice as much oxygen is absorbed by the lung tissue as in a land mammal. As with all mammals, the oxygen is stored in the blood and the lungs, but in cetaceans, it is also stored in various tissues, mainly in the muscles. The muscle pigment, myoglobin , provides an effective bond. This additional oxygen storage

14040-455: The various SeaWorld parks in the United States. Other species kept in captivity are spotted dolphins , gray whales , false killer whales , pilot whales and common dolphins , Commerson's dolphins , as well as rough-toothed dolphins , but all in much lower numbers than the bottlenose dolphin. There are fewer than ten Amazon river dolphins , Risso's dolphins , or tucuxi in captivity. Two unusual and very rare hybrid dolphins ( wolphins ,

14160-577: The water by emitting clicks and listening for echoes, as do other members of the dolphin family. The mean body temperature of the orca is 36 to 38 °C (97 to 100 °F). Like most marine mammals, orcas have a layer of insulating blubber ranging from 7.6 to 10 cm (3.0 to 3.9 in) thick beneath the skin. The pulse is about 60 heartbeats per minute when the orca is at the surface, dropping to 30 beats/min when submerged. An individual orca can often be identified from its dorsal fin and saddle patch. Variations such as nicks, scratches, and tears on

14280-705: The water. Balaenids ( right whales and bowhead whales ) have massive heads that can make up 40% of their body mass. Most mysticetes prefer the food-rich colder waters of the Northern and Southern Hemispheres, migrating to the Equator to give birth. During this process, they are capable of fasting for several months, relying on their fat reserves. The parvorder of Odontocetes – the toothed whales – include sperm whales, beaked whales, orcas, dolphins and porpoises. Generally their teeth have evolved to catch fish, squid or other marine invertebrates , not for chewing them, so prey

14400-407: The wild. Cetaceans also face severe environmental hazards from underwater noise pollution , entanglement in abandoned ropes and nets, collisions with ships, plastic and heavy metals build-up, to accelerating climate change , but how much they are affected varies widely from species to species, from minimally in the case of the southern bottlenose whale to the baiji (Chinese river dolphin) which

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