160-462: See text . Oceanic dolphins or Delphinidae are a widely distributed family of dolphins that live in the sea . Close to forty extant species are recognised. They include several big species whose common names contain "whale" rather than "dolphin", such as the Globicephalinae (round-headed whales, which include the false killer whale and pilot whale ). Delphinidae is a family within
320-530: A dolphinarium . Bottlenose dolphins are the most common species of dolphin kept in dolphinariums as they are relatively easy to train, have a long lifespan in captivity and have a friendly appearance. Hundreds if not thousands of bottlenose dolphins live in captivity across the world, though exact numbers are hard to determine. Other species kept in captivity are spotted dolphins , false killer whales and common dolphins , Commerson's dolphins , as well as rough-toothed dolphins , but all in much lower numbers than
480-445: A dorsal fin to prevent themselves from involuntarily spinning in the water. The oceanic dolphin ear is specifically adapted to the marine environment. In humans, the middle ear works as an impedance equalizer between the outside air's low impedance and the cochlear fluid's high impedance. In dolphins, and other marine mammals, there is no great difference between the outer and inner environments. Instead of sound passing through
640-620: A bay, where they become stranded and are then slaughtered. This practice was common in both the 19th and 20th centuries. The whales were hunted for bone, meat, oil, and fertilizer. In the Faroe Islands , pilot whale hunting started at least in the 16th century, and continued into modern times, with thousands being killed during the 1970s and 1980s. In other parts of the North Atlantic, such as Norway , West Greenland, Ireland and Cape Cod , pilot whales have also been hunted, but to
800-407: A body length of approximately 6.5 m, with males being 1 m longer than females. Their body mass reaches up to 1,300 kg in females and up to 2,300 kg in males. For short-finned pilot whales, adult females reach a body length of about 5.5 m, while males reach 7.2 m and may weigh up to 3,200 kg. Pilot whales can be found in oceans nearly worldwide, but data about current population sizes
960-636: A dolphin in his coat of arms as King of Naples and Sicily. In contemporary days, a dolphin is still used in the coat of arms of many cities, as well as in the coat of arms of Anguilla and the coat of arms of Romania , and the coat of arms of Barbados has a dolphin supporter . Cardinal Angelo Amato , prefect of the Congregation of the Causes of Saints , a dolphin in his coat of arms, as well as Cardinal Godfried Danneels , former Metropolitan Archbishop of Mechelen-Brussels . Dolphin A dolphin
1120-421: A dolphin-friendly way. The earliest campaigns with "Dolphin safe" labels were initiated in the 1980s as a result of cooperation between marine activists and the major tuna companies, and involved decreasing incidental dolphin kills by up to 50% by changing the type of nets used to catch tuna. The dolphins are netted only while fishermen are in pursuit of smaller tuna. Albacore are not netted this way, making albacore
1280-445: A few minutes. Feeding dives may last over ten minutes. They are capable of diving to depths of 600 meters, but most dives are to a depth of 30–60 m. Shallow dives tend to take place during the day, while deeper ones take place at night. When making deep dives, pilot whales often make fast sprints to catch fast-moving prey such as squid. Compared to sperm whales and beaked whales , foraging short-finned pilot whales are more energetic at
1440-433: A few, such as the orca, feed on large mammals such as seals. Male dolphins typically mate with multiple females every year, but females only mate every two to three years. Calves are typically born in the spring and summer months and females bear all the responsibility for raising them. Mothers of some species fast and nurse their young for a relatively long period of time. Dolphins produce a variety of vocalizations, usually in
1600-674: A flavor very similar to beef liver . Dolphin meat is high in mercury, and may pose a health danger to humans when consumed. The Faroe Islands population was exposed to methylmercury largely from contaminated pilot whale meat, which contained very high levels of about 2 mg methylmercury/kg. However, the Faroe Islands populations also eat significant amounts of fish. The study of about 900 Faroese children showed that prenatal exposure to methylmercury resulted in neuropsychological deficits at 7 years of age – World Health Organization There have been human health concerns associated with
1760-425: A fully asleep state where both eyes are closed and there is no response to mild external stimuli. In this case, respiration is automatic; a tail kick reflex keeps the blowhole above the water if necessary. Anesthetized dolphins initially show a tail kick reflex. Though a similar state has been observed with wild sperm whales , it is not known if dolphins in the wild reach this state. The Indus river dolphin has
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#17327721304521920-557: A grey saddle patch behind the dorsal fin . Other light areas are an anchor-shaped patch under the chin, a faint blaze marking behind the eye, a large marking on the belly, and a genital patch. The dorsal fin is set forward on the back and sweeps backwards. A pilot whale is more robust than most dolphins and has a distinctive large, bulbous melon . Pilot whales' long, sickle-shaped flippers and tail stocks are flattened from side to side. Male long-finned pilot whales develop more circular melons than females, although this does not seem to be
2080-576: A leader. They are also called "pothead whales" and "blackfish". The genus name is a combination of the Latin word globus ("round ball" or "globe") and the Greek word Kephale ("head"). Pilot whales are classified into two species; the long-finned pilot whale ( Globicephala melas ) and the short-finned pilot whale ( G. macrorhynchus ). The short-finned pilot whale was described, from skeletal materials only, by John Edward Gray in 1846. He presumed from
2240-477: A lesser extent. One fishery at Cape Cod harvested 2,000–3,000 whales per year during the late 19th and early 20th centuries. Newfoundland 's long-finned pilot whale fishery was at its highest in 1956, but declined shortly after and is now defunct. In the Southern Hemisphere, exploitation of long-finned pilot whales has been sporadic and low. Currently, long-finned pilot whales are only hunted at
2400-401: A male and a harem of females. Individuals communicate by sound, producing low-frequency whistles, and also produce high-frequency broadband clicks of 80–220 kHz, which are primarily used for echolocation . Gestation lasts from 10 to 18 months, and results in the birth of a single calf. Some species are well adapted for diving to great depths. They have a layer of fat, or blubber , under
2560-465: A male dolphin is, the more likely his body is to be covered with bite scars. Male dolphins can get into disputes over companions and females. Acts of aggression can become so intense that targeted dolphins sometimes go into exile after losing a fight. Male bottlenose dolphins have been known to engage in infanticide . Dolphins have also been known to kill porpoises (porpicide) for reasons which are not fully understood, as porpoises generally do not share
2720-419: A more limited capacity for color vision than most mammals. Most dolphins have slightly flattened eyeballs, enlarged pupils (which shrink as they surface to prevent damage), slightly flattened corneas and a tapetum lucidum (eye tissue behind the retina); these adaptations allow for large amounts of light to pass through the eye and, therefore, a very clear image of the surrounding area. They also have glands on
2880-450: A more limited capacity for color vision than most mammals. Most dolphins have slightly flattened eyeballs, enlarged pupils (which shrink as they surface to prevent damage), slightly flattened corneas and a tapetum lucidum ; these adaptations allow for large amounts of light to pass through the eye and, therefore, a very clear image of the surrounding area. They also have glands on the eyelids and outer corneal layer that act as protection for
3040-421: A newborn pilot whale travelling alongside her was observed off Western Iceland, leading scientists to question whether the relationship between these species might be far more complex than previously suggested. It is not known whether the newborn was adopted or abducted, but this same female killer whale was seen a year later interacting with a larger group of pilot whales. Of the cetaceans, pilot whales are among
3200-452: A pod does not seem to occur. During aggregations, males will temporarily leave their pods to mate with females from other pods. Male reproductive dominance or competition for mates does not seem to exist. After mating, a male pilot whale usually spends only a few months with a female, and an individual may sire several offspring in the same pod. Males return to their own pods when the aggregations disband, and their presence may contribute to
3360-498: A quality cut of beef , with distinct yet subtle undertones recalling its marine origin. In both Japan and the Faroe Islands, the meat is contaminated with mercury and cadmium, causing a health risk for those who frequently eat it, especially children and pregnant women. In November 2008, an article in New Scientist reported that research done on the Faroe Islands resulted in two chief medical officers recommending against
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#17327721304523520-573: A short timespan. The gestation period varies with species; for the small tucuxi dolphin , this period is around 11 to 12 months, while for the orca, the gestation period is around 17 months. Typically dolphins give birth to a single calf, which is, unlike most other mammals, born tail first in most cases. They usually become sexually active at a young age, even before reaching sexual maturity . The age of sexual maturity varies by species and sex. Dolphins are known to display non-reproductive sexual behavior , engaging in masturbation , stimulation of
3680-448: A sick member of their group that got stranded. The pod also may be following a member of high importance that got stranded and a secondary social response makes them keep returning. Researchers from New Zealand have successfully used secondary social responses to keep a stranding pod of long-finned pilot whales from returning to the beach. In addition, the young members of the pod were taken offshore to buoys, and their distress calls lured
3840-401: A signature whistle of an individual they have not encountered for over twenty years. Research done on signature whistle usage by other dolphin species is relatively limited. The research on other species done so far has yielded varied outcomes and inconclusive results. Oceanic dolphins frequently leap above the water surface, this being done for various reasons. When travelling, jumping can save
4000-419: A sleep method that is different from that of other dolphin species. Living in water with strong currents and potentially dangerous floating debris, it must swim continuously to avoid injury. As a result, this species sleeps in very short bursts which last between 4 and 60 seconds. There are various feeding methods among and within species, some apparently exclusive to a single population. Fish and squid are
4160-473: A thick layer of blubber , the thickness of which depends on how far the species lives from the equator. This blubber also helps keep the animal warm providing insulation from the harsh climate or cold depths. It can also aid in protection to some extent as predators would have a hard time getting through a thick layer of fat. Calves are born with only a thin layer of blubber, but some species compensate for this with lanugos . Oceanic dolphins have two flippers on
4320-411: A thin layer of blubber, which develops at different paces depending on the habitat. Dolphins have a two-chambered stomach that is similar in structure to terrestrial carnivores. They have fundic and pyloric chambers. Dolphins' reproductive organs are located inside the body, with genital slits on the ventral (belly) side. Males have two slits, one concealing the penis and one further behind for
4480-821: A year in the mid-1990s. In 1988, 141 whales caught on the east coast of the U.S. were taken by the foreign Atlantic mackerel fishery, which forced it to be shut down. As with other marine mammals, pilot whales are susceptible to certain pollutants. Off the Faroes, France, the UK, and the eastern US, pilot whales were found to have been contaminated with high amounts of DDT and PCB . Pollutants such as DDT and mercury can be passed from mothers to their babies during gestation and lactation. The Faroes whales have also been contaminated with cadmium and mercury . However, pilot whales from Newfoundland and Tasmania were found to have had very low levels of DDT. Short-finned pilot whales off
4640-588: Is accompanied by more complex whistles and pulsed sounds. The number of whistles made increases with the number of subgroups and the distance in which the whales are spread apart. A study of short-finned pilot whales off the southwest coast of Tenerife in the Canary Islands has found the members of a pod maintained contact with each other through call repertoires unique to their pod. A later study found, when foraging at around 800 m deep, short-finned pilot whales make tonal calls. The number and length of
4800-433: Is accompanied by simple vocalizations. Differences have been found in the calls of the two species. Compared with short-finned pilot whales, long-finned pilot whales have relatively low-frequency calls with narrow frequency ranges. In one study of North Atlantic long-finned pilot whales, certain vocalizations were heard to accompany certain behaviors. When resting or "milling", simple whistles are emitted. Surfacing behavior
4960-447: Is adapted for both air and water; it is so well developed that some can survive even if they are blind. 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. Dolphins are widespread. Most species prefer the warm waters of the tropic zones, but some, such as the right whale dolphin , prefer colder climates. Dolphins feed largely on fish and squid, but
Oceanic dolphin - Misplaced Pages Continue
5120-403: Is also known as kinesthesia, is the body's ability to sense its location, movements and actions. Dolphins are sensitive to vibrations and small pressure changes. Blood vessels and nerve endings can be found within the dermis. There is a plexus of parallel running arteries and veins in the dorsal fin, fluke, and flippers. The blubber manipulates the blood vessels to help the dolphin stay warm. When
5280-525: Is an aquatic mammal in the clade Odontoceti ( toothed whale ). Dolphins belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins ), Iniidae (the New World river dolphins), Pontoporiidae (the brackish dolphins), and possibly extinct Lipotidae (baiji or Chinese river dolphin). There are 40 extant species named as dolphins. Dolphins range in size from
5440-573: Is called a school or a pod . Male dolphins are called bulls , females are called cows and young dolphins are called calves . In 1933, three hybrid dolphins beached off the Irish coast; they were hybrids between Risso's and bottlenose dolphins. This mating was later repeated in captivity, producing a hybrid calf. In captivity, a bottlenose and a rough-toothed dolphin produced hybrid offspring. A common-bottlenose hybrid lives at SeaWorld California. Other dolphin hybrids live in captivity around
5600-451: Is contained in the layer of blubber beneath the skin, and the muscle is high in myoglobin, the meat is a dark shade of red. In Japan, where pilot whale meat can be found in certain restaurants and izakayas , the meat is sometimes served raw, as sashimi , but just as often pilot whale steaks are marinated, cut into small chunks, and grilled. When grilled, the meat is slightly flaky and quite flavorful, somewhat gamey, though similar to
5760-522: Is deficient. The long-finned pilot whale prefers slightly cooler waters than the short-finned and is divided into two populations. The smaller group is found in a circumpolar band in the Southern Ocean from about 20 to 65°S . It may be sighted off the coasts of Chile , Argentina , South Africa , Australia , and New Zealand . An estimated more than 200,000 individuals were in this population in 2006. The second, much larger, population inhabits
5920-576: Is found in temperate and tropical waters of the Indian , Atlantic and Pacific Oceans. Its population overlaps slightly with the long-finned pilot whale in the temperate waters of the North Atlantic and Southern Oceans. About 150,000 individuals are found in the eastern tropical Pacific Ocean. More than 30,000 animals are estimated in the western Pacific, off the coast of Japan. Pilot whales are generally nomadic, but some populations stay year-round in places such as Hawaii and parts of California. They prefer
6080-494: Is herding, where a pod squeezes a school of fish into a bait ball . Individual members then take turns plowing through the ball, feeding on the stunned fish. Corralling is a method where dolphins chase fish into shallow water to catch them more easily. Orca and bottlenose dolphins have also been known to drive their prey onto a beach to feed on it, a behavior known as beach or strand feeding. Some species also whack fish with their flukes, stunning them and sometimes knocking them out of
6240-408: Is home to elongated spindle neurons that, prior to 2007, were known only in hominids. In humans, these cells are involved in social conduct, emotions, judgment, and theory of mind. Cetacean spindle neurons are found in areas of the brain that are analogous to where they are found in humans, suggesting that they perform a similar function. Brain size was previously considered a major indicator of
6400-495: Is located in a layer of blubber between the meat and the skin. When dolphin meat is eaten in Japan, it is often cut into thin strips and eaten raw as sashimi , garnished with onion and either horseradish or grated garlic , much as with sashimi of whale or horse meat ( basashi ). When cooked, dolphin meat is cut into bite-size cubes and then batter-fried or simmered in a miso sauce with vegetables. Cooked dolphin meat has
6560-701: Is mostly transferred by mothers to daughters, unlike simian primates, where knowledge is generally passed on to both sexes. Using sponges as mouth protection is a learned behavior. Another learned behavior was discovered among river dolphins in Brazil, where some male dolphins use weeds and sticks as part of a sexual display. Forms of care-giving between fellows and even for members of different species (see Moko (dolphin) ) are recorded in various species – such as trying to save weakened fellows or female pilot whales holding up dead calves for long periods. Dolphins engage in acts of aggression towards each other. The older
Oceanic dolphin - Misplaced Pages Continue
6720-433: Is much less definitive than when used for primates, because primates can touch the mark or the mirror, while cetaceans cannot, making their alleged self-recognition behavior less certain. Skeptics argue that behaviors that are said to identify self-awareness resemble existing social behaviors, and so researchers could be misinterpreting self-awareness for social responses to another individual. The researchers counter-argue that
6880-545: Is no great difference between the outer and inner environments. Instead of sound passing through the outer ear to the middle ear, dolphins receive sound through the throat, from which it passes through a low-impedance fat-filled cavity to the inner ear. The ear is acoustically isolated from the skull by air-filled sinus pockets, which allow for greater directional hearing underwater. Dolphins generate sounds independently of respiration using recycled air that passes through air sacs and phonic (alternatively monkey) lips. Integral to
7040-441: Is not as common in females of long-finned pilot whales. Postreproductive females possibly play important roles in the survival of the young. Postreproductive females will continue to lactate and nurse young. Since they can no longer bear young of their own, these females invest in the current young, allowing them to feed even though they are not their own. Short-finned pilot whales grow more slowly than long-finned pilot whales. For
7200-620: Is not rigid; interchange is common. They establish strong social bonds, and will stay with injured or ill members, helping them to breathe by bringing them to the surface if needed. This altruism does not appear to be limited to their own species. The dolphin Moko in New Zealand has been observed guiding a female pygmy sperm whale together with her calf out of shallow water where they had stranded several times. They have also been seen protecting swimmers from sharks by swimming circles around
7360-552: Is relatively small for its size, yet they do retain a good degree of eyesight. As well as this, the eyes of a dolphin are placed on the sides of its head, so their vision consists of two fields, rather than a binocular view like humans have. When dolphins surface, their lens and cornea correct the nearsightedness that results from the refraction of light; they contain both rod and cone cells, meaning they can see in both dim and bright light. Dolphins do, however, lack short wavelength sensitive visual pigments in their cone cells indicating
7520-418: Is seen, by some, to be a sign of highly developed, abstract thinking. Self-awareness, though not well-defined scientifically, is believed to be the precursor to more advanced processes like meta-cognitive reasoning (thinking about thinking) that are typical of humans. Research in this field has suggested that cetaceans, among others, possess self-awareness. The most widely used test for self-awareness in animals
7680-684: Is the bottlenose dolphin , while there are around 60 orcas in captivity . The name is originally from Greek δελφίς ( delphís ), "dolphin", which was related to the Greek δελφύς ( delphus ), "womb". The animal's name can therefore be interpreted as meaning "a 'fish' with a womb". The name was transmitted via the Latin delphinus (the romanization of the later Greek δελφῖνος – delphinos ), which in Medieval Latin became dolfinus and in Old French daulphin , which reintroduced
7840-460: Is the mirror test in which a mirror is introduced to an animal, and the animal is then marked with a temporary dye. If the animal then goes to the mirror in order to view the mark, it has exhibited strong evidence of self-awareness. Some disagree with these findings, arguing that the results of these tests are open to human interpretation and susceptible to the Clever Hans effect. This test
8000-535: Is the mirror test in which a temporary dye is placed on an animal's body, and the animal is then presented with a mirror; they then see if the animal shows signs of self-recognition. In 1995, Marten and Psarakos used television to test dolphin self-awareness. They showed dolphins real-time footage of themselves, recorded footage, and another dolphin. They concluded that their evidence suggested self-awareness rather than social behavior. While this particular study has not been repeated since then, dolphins have since passed
8160-574: The Convention on the Conservation of Migratory Species of Wild Animals (CMS). Those from northwest and northeast Atlantic may also need to be included to Appendix II of CMS. The short-finned pilot whale is listed on Appendix II of CITES . The long-finned pilot whale has traditionally been hunted by " driving ", which involves many hunters and boats gathering in a semicircle behind a pod of whales close to shore, and slowly driving them towards
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#17327721304528320-690: The Dauphin de Viennois (later Dauphin of France ) through which it passed to the Counts of Forez , Albon and other French families, as well as several branches of the Bourbon family ( Count of Montpensier , Count of Beaujolais , among others) the Pandolfini of Florence, and the Delfini of Venice and Rome also used the dolphin as their "canting" armories. In the 19th century, Joseph Bonaparte adopted
8480-478: The Middle Ages , not much was known about the biology of the dolphin and it was often depicted as a sort of fish. Traditionally, the dolphins in heraldry still may take after this notion, sometimes showing the dolphin skin covered with fish scales . In the Middle Ages , the dolphin became an important heraldic element in the coats of arms of several European noble families, the most noticeable being those of
8640-574: The ancient Roman author and natural philosopher Pliny the Elder . A modern human-dolphin partnership currently operates in Laguna , Santa Catarina, Brazil. Here, dolphins drive fish towards fishermen waiting along the shore and signal the men to cast their nets. The dolphins' reward is the fish that escape the nets. Pilot whale Globicephala macrorhynchus Globicephala melas Globicephalus Pilot whales are cetaceans belonging to
8800-419: The anus . Females have one genital slit, housing the vagina and the anus, with a mammary slit on either side. The integumentary system is an organ system mostly consisting of skin, hair, nails and endocrine glands. The skin of dolphins is specialized to satisfy specific requirements, including protection, fat storage, heat regulation, and sensory perception. The skin of a dolphin is made up of two parts:
8960-485: The artiodactyl order (even-toed ungulates). They are related to the Indohyus , an extinct chevrotain -like ungulate, from which they split approximately 48 million years ago. The primitive cetaceans, or archaeocetes , first took to the sea approximately 49 million years ago and became fully aquatic by 5–10 million years later. Archaeoceti is a parvorder comprising ancient whales. These ancient whales are
9120-489: 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
9280-432: The mahi-mahi fish is called the dolphinfish. In common usage, the term whale is used only for the larger cetacean species, while the smaller ones with a beaked or longer nose are considered dolphins. The name dolphin is used casually as a synonym for bottlenose dolphin , the most common and familiar species of dolphin. There are six species of dolphins commonly thought of as whales, collectively known as blackfish :
9440-506: The orca , the melon-headed whale , the pygmy killer whale , the false killer whale , and the two species of pilot whales , all of which are classified under the family Delphinidae and qualify as dolphins. Although the terms dolphin and porpoise are sometimes used interchangeably, porpoise usually refers to the Phocoenidae family, which have a shorter beak and spade-shaped teeth and differ in their behavior. A group of dolphins
9600-450: The orca , the melon-headed whale , the pygmy killer whale , the false killer whale , and the two species of pilot whales , but they are classified under the family Delphinidae . Recent molecular analyses indicate that several delphinid genera (especially Stenella and Lagenorhynchus ) are not monophyletic as currently recognized. Thus, significant taxonomic revisions within the family are likely. Extinct taxon, according to
9760-418: The ph into the word dolphin . The term mereswine ("sea pig") is also used. The term dolphin can be used to refer to most species in the family Delphinidae (oceanic dolphins) and the river dolphin families of Iniidae (South American river dolphins), Pontoporiidae ( La Plata dolphin ), Lipotidae (Yangtze river dolphin) and Platanistidae (Ganges river dolphin and Indus river dolphin). Meanwhile,
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#17327721304529920-607: The 1.7-metre-long (5 ft 7 in) and 50-kilogram (110-pound) Maui's dolphin to the 9.5 m (31 ft) and 10-tonne (11-short-ton) orca . Various species of dolphins exhibit sexual dimorphism where the males are larger than females. They have streamlined bodies and two limbs that are modified into flippers. Though not quite as flexible as seals , they are faster; some dolphins can briefly travel at speeds of 29 kilometres per hour (18 mph) or leap about 9 metres (30 ft). Dolphins use their conical teeth to capture fast-moving prey . They have well-developed hearing which
10080-861: The 1960s resulted in the appearance of many dolphinaria around the world, making dolphins accessible to the public. Criticism and animal welfare laws forced many to close, although hundreds still exist around the world. In the United States , the best known are the SeaWorld marine mammal parks . In the Middle East the best known are Dolphin Bay at Atlantis, The Palm and the Dubai Dolphinarium . Various species of dolphins are kept in captivity. These small cetaceans are more often than not kept in theme parks, such as SeaWorld , commonly known as
10240-644: The 1970s and early 1980s, six pilot whales were captured alive by drive hunts and taken for public display. Pilot whales have historically had low survival rates in captivity, with the average annual survival being 0.51 years during the mid-1960s to early 1970s. There have been a few exceptions to the rule. Bubbles, a female short-finned pilot whale, who was displayed in Marineland of the Pacific and eventually at Sea World California, lived to be somewhere in her 50s when she eventually died on 12 June 2016. In 1968,
10400-573: The 9.5 m (31 ft 2 in) and 10 t (11 short tons) orca . Overall, they tend to be dwarfed by other Cetartiodactyls . Several species have female-biased sexual dimorphism, with the females being larger than the males. Dolphins have conical teeth, as opposed to porpoises ' spade-shaped teeth. These conical teeth are used to catch swift prey such as fish, squid or large mammals, such as seals. Breathing involves expelling stale air from their blowhole , in an upward blast, which may be visible in cold air, followed by inhaling fresh air into
10560-485: The Faroe Islands and Greenland. According to the IUCN the harvesting of this species for food in the Faroe Islands and Greenland has not resulted in any detectable declines in abundance. The short-finned pilot whale has also been hunted for many centuries, particularly by Japanese whalers . Between 1948 and 1980, hundreds of whales were exploited at Hokkaido and Sanriku in the north and Taiji , Izu , and Okinawa in
10720-668: The North Atlantic Ocean , in a band from South Carolina in the United States across to the Azores and Morocco at its southern edge and from Newfoundland to Greenland , Iceland, and northern Norway at its northern limit. This population was estimated at 778,000 individuals in 1989. It is also present in the western half of the Mediterranean Sea . The short-finned pilot whale is less populous. It
10880-489: The Paleobiology Database. The Delphinidae are the most diverse of the cetacean families, with numerous variations between species. They range in size from 1.2 m (3 ft 11 in) and 40 kg (88 lb) ( Haviside's dolphin ), to 9 m (30 ft) and 10 tonnes (orca). Most species weigh between 50 and 200 kg (110 and 440 lb). They typically have curved dorsal fins, clear 'beaks' at
11040-565: The Warner Bros film Free Willy . Dolphins are sometimes kept in captivity and trained to perform in shows. The most common species of dolphin in captivity is the bottlenose dolphin , and less than 50 orca were found in oceanariums in 2012. Delphinids, especially bottlenose dolphins, are able to hybridize with a wide variety of other delphinid species; wholphins are just one of many possible hybrids. Six species, sometimes referred to as "blackfish", are dolphins commonly called whales:
11200-401: The animal with an idea on an object's shape and size, though how exactly this works is not yet understood. The small hairs on the rostrum of the boto (river dolphins of South America) are believed to function as a tactile sense , possibly to compensate for the boto's poor eyesight. A dolphin eye is relatively small for its size, yet they do retain a good degree of eyesight. As well as this,
11360-674: The behaviors shown are evidence of self-awareness, as they are very different from normal responses to another individual. Whereas apes can merely touch the mark on themselves with their fingers, cetaceans show less definitive behavior of self-awareness; they can only twist and turn themselves to observe the mark. In 1995, Marten and Psarakos used television to test dolphin self-awareness. They showed dolphins real-time video of themselves, video of another dolphin and recorded footage. They concluded that their evidence suggested self-awareness rather than social behavior. While this particular study has not been repeated since then, dolphins have since passed
11520-527: The body and to form specialized locomotor structures such as the dorsal fin, propulsive fluke blades and caudal keels. There are many nerve endings that resemble small, onion-like configurations that are present in the superficial portion of the dermis. Mechanoreceptors are found within the interlocks of the epidermis with dermal ridges. There are nerve fibers in the dermis that extend to the epidermis. These nerve endings are known to be highly proprioceptive , which explains sensory perception. Proprioception, which
11680-546: The bottlenose dolphin. There are also fewer than ten pilot whales , Amazon river dolphins , Risso's dolphins , spinner dolphins , or tucuxi in captivity. Two unusual and very rare hybrid dolphins, known as wholphins , are kept at the Sea Life Park in Hawaii , which is a cross between a bottlenose dolphin and a false killer whale . Also, two common /bottlenose hybrids reside in captivity: one at Discovery Cove and
11840-473: The brain that are homologous to where they are found in humans, suggesting that they perform a similar function. Brain size was previously considered a major indicator of the intelligence of an animal. Since most of the brain is used for maintaining bodily functions, greater ratios of brain to body mass may increase the amount of brain mass available for more complex cognitive tasks. Allometric analysis indicates that mammalian brain size scales at approximately
12000-404: The calls seem to decrease with depth despite being farther away from conspecifics at the surface. As such, the surrounding water pressure affects the energy of the calls, but it does not appear to affect the frequency levels. When in stressful situations, pilot whales produce "shrills" or "plaintive cries", which are variations of their whistles. To elude predators, long-finned pilot whales off
12160-430: The case for long-finned pilot whales. In 2024, a gps-fitted long-finned pilot whale recorded a diving depth over 1,100 meters. Pilot whales are often infested with whale lice , cestodes , and nematodes . They also can be hosts to various pathogenic bacteria and viruses, such as Streptococcus , Pseudomonas , Escherichia , Staphylococcus , and influenza . One sample of Newfoundland pilot whales found that
12320-441: The case for short-finned pilot whales off the Pacific coast of Japan. Long-finned and short-finned pilot whales are so similar, it is difficult to tell the two species apart. They were traditionally differentiated by the length of the pectoral flippers relative to total body length and the number of teeth. The long-finned pilot whale was thought to have 9–12 teeth in each row and flippers one-fifth of total body length, compared to
12480-507: The case of the orca, also eat marine mammals and birds. All, however, are purely carnivorous . They typically have between 100 and 200 teeth, although a few species have considerably fewer. Various methods of feeding exist among and within oceanic species, some apparently exclusive to a single population. Fish and squid are the main food, but the false killer whale and the orca also feed on other marine mammals. Orca on occasion also hunt whales larger than themselves. One common feeding method
12640-485: The closest living relatives of cetaceans are the hippopotamuses ; these share a semi-aquatic ancestor that branched off from other artiodactyls some 60 million years ago. Around 40 million years ago, a common ancestor between the two branched off into cetacea and anthracotheres ; anthracotheres became extinct at the end of the Pleistocene two-and-a-half million years ago, eventually leaving only one surviving lineage:
12800-443: The consumption of dolphin meat in Japan after tests showed that dolphin meat contained high levels of mercury . There are no known cases of mercury poisoning as a result of consuming dolphin meat, though the government continues to monitor people in areas where dolphin meat consumption is high. The Japanese government recommends that children and pregnant women avoid eating dolphin meat on a regular basis. Similar concerns exist with
12960-654: The consumption of dolphin meat in the Faroe Islands , where prenatal exposure to methylmercury and PCBs primarily from the consumption of pilot whale meat has resulted in neuropsychological deficits amongst children. Legally consuming dolphin meat in the United States would be near impossible for most due to the Marine Mammal Protection Act , which forbids "...the act of hunting, killing, capture, and/or harassment of any marine mammal..." (Exceptions are made for certain groups of people, such as Alaska Natives .) Theoretically, one could only eat
13120-401: The consumption of pilot whale meat, considering it to be too toxic. In 2008, the local authorities recommended that pilot whale meat should no longer be eaten due to the contamination. This has resulted in reduced consumption, according to a senior Faroese health official. Pilot whales, mostly short-finned pilot whales, have been kept in captivity in various marine parks, arguably starting in
13280-495: The cornea. The olfactory lobes are absent in oceanic dolphins, suggesting that they have no sense of smell. Oceanic dolphins are not thought to have a good sense of taste, as their taste buds are atrophied or missing altogether. However, some have preferences between different kinds of fish, indicating some sort of attachment to taste. Most delphinids primarily eat fish, along with a smaller number of squid and small crustaceans, but some species specialize in eating squid, or, in
13440-491: The dispersal of their prey. Fish that are consumed include Atlantic cod , Greenland turbot, Atlantic mackerel , Atlantic herring , hake , and spiny dogfish in the northwest Atlantic. In the Faroe Islands , whales mostly eat squid, but will also eat fish species such as greater argentine and blue whiting . However, Faroe whales do not seem to feed on cod , herring , or mackerel , even when they are abundant. Pilot whales generally take several breaths before diving for
13600-466: The dolphin energy as there is less friction while in the air. This type of travel is known as porpoising. Other reasons include orientation, social displays, fighting, non-verbal communication , entertainment and attempting to dislodge parasites . Dolphins show various types of playful behavior , often including objects, self-made bubble rings , other dolphins, or other animals. When playing with objects or small animals, common behavior includes carrying
13760-425: The dolphin equivalent of a name for humans. These signature whistles are developed during a dolphin's first year; it continues to maintain the same sound throughout its lifetime. In order to obtain each individual whistle sound, dolphins undergo vocal production learning. This consists of an experience with other dolphins that modifies the signal structure of an existing whistle sound. An auditory experience influences
13920-402: The dorsal fin, flukes, and flippers. These thermal windows are a good way for dolphins to get rid of excess heat if overheating. Additionally in order to conserve heat, dolphins use countercurrent heat exchange. Blood flows in different directions in order for heat to transfer across membranes. Heat from warm blood leaving the heart will heat up the cold blood that is headed back to the heart from
14080-659: The east coast of Japan, which comprise genetically isolated stocks. Fossils of an extinct relative, Globicephala baereckeii , have been found in Pleistocene deposits in Florida. Another Globicephala dolphin was discovered in Pliocene strata in Tuscany, Italy, and was named G. etruriae . Evolution of Tappanaga , the endemic, larger form of short-finned pilots found in northern Japan, with similar characteristics to
14240-413: The epidermal layer. The thickness of a dolphin's epidermis varies, depending on species and age. Blubber is found within the dermis and subcutis layer. The dermis blends gradually with the adipose layer, which is known as fat, because the fat may extend up to the epidermis border and collagen fiber bundles extend throughout the whole subcutaneous blubber which is fat found under the skin. The thickness of
14400-411: The epidermis and the blubber, which consists of two layers including the dermis and subcutis. The dolphin's skin is known to have a smooth rubber texture and is without hair and glands, except mammary glands. At birth, a newborn dolphin has hairs lined up in a single band on both sides of the rostrum, which is their jaw, and usually has a total length of 16–17 cm . The epidermis is characterized by
14560-511: The extremities, meaning that the heart always has warm blood and it decreases the heat lost to the water in those thermal windows. Dolphins have two pectoral flippers, each containing four digits, a boneless dorsal fin for stability, and a fluke for propulsion. Although dolphins do not possess external hind limbs, some possess discrete rudimentary appendages, which may contain feet and digits. Orcas are fast swimmers in comparison to seals which typically cruise at 9–28 km/h (5.6–17.4 mph);
14720-484: The eyelids and outer corneal layer that act as protection for the cornea. The olfactory lobes and nerve are absent in dolphins, suggesting that they have no sense of smell. Dolphins are not thought to have a good sense of taste, as their taste buds are atrophied or missing altogether. Some have preferences for different kinds of fish, indicating some ability to taste. Dolphins are known to teach, learn, cooperate, scheme, and grieve. The neocortex of many species
14880-511: The eyes of a dolphin are placed on the sides of its head, so their vision consists of two fields, rather than a binocular view like humans have. When dolphins surface, their lens and cornea correct the nearsightedness that results from the water's refraction of light. Their eyes contain both rod and cone cells, meaning they can see in both dim and bright light, but they have far more rod cells than they do cone cells. They lack short wavelength sensitive visual pigments in their cone cells, indicating
15040-447: The females by their side by means of both physical aggression and intimidation, to increase their chances of reproductive success. Generally, dolphins sleep with only one brain hemisphere in slow-wave sleep at a time, thus maintaining enough consciousness to breathe and to watch for possible predators and other threats. Sleep stages earlier in sleep can occur simultaneously in both hemispheres. In captivity, dolphins seemingly enter
15200-414: The form of clicks and whistles. Dolphins are sometimes hunted in places such as Japan, in an activity known as dolphin drive hunting . Besides drive hunting, they also face threats from bycatch , habitat loss, and marine pollution . Dolphins have been depicted in various cultures worldwide. Dolphins are sometimes kept in captivity and trained to perform tricks. The most common dolphin species in captivity
15360-452: The front of their heads, and forehead melons , although exceptions to all of these rules are found. They have a wide range of colors and patterns. Oceanic dolphins have a torpedo-shaped, muscular body with an inflexible neck, limbs modified into flippers, nonexistent external ear flaps, a large tail fin, and a bulbous head. A dolphin skull has small eye orbits, a long snout, but not as long as its river dolphin counterpart, and eyes placed on
15520-539: The genital area of other individuals using the rostrum or flippers, and homosexual contact . Various species of dolphin have been known to engage in sexual behavior including copulation with dolphins of other species, and occasionally exhibit sexual behavior towards other animals , including humans. Sexual encounters may be violent, with male bottlenose dolphins sometimes showing aggressive behavior towards both females and other males. Male dolphins may also work together and attempt to herd females in estrus , keeping
15680-443: The hearing set-up that channeled vibrations from the jaw to the earbone which occurred with Ambulocetus 49 million years ago, a streamlining of the body and the growth of flukes on the tail which occurred around 43 million years ago with Protocetus , the migration of the nasal openings toward the top of the cranium and the modification of the forelimbs into flippers which occurred with Basilosaurus 35 million years ago, and
15840-432: The heart, brain and other organs. Their hemoglobin and myoglobin store oxygen in body tissues, and they have twice as much myoglobin as hemoglobin. [REDACTED] A dolphin ear has specific adaptations to the marine environment. In humans, the middle ear works as an impedance equalizer between the outside air's low impedance and the cochlear fluid's high impedance. In dolphins, and other marine mammals, there
16000-563: The intelligence of an animal. Since most of the brain is used for maintaining bodily functions, greater ratios of brain to body mass may increase the amount of brain mass available for more complex cognitive tasks. Allometric analysis indicates that mammalian brain size scales at approximately the ⅔ or ¾ exponent of the body mass. Comparison of a particular animal's brain size with the expected brain size based on such allometric analysis provides an encephalization quotient that can be used as another indication of animal intelligence. Orcas have
16160-403: The lack of keratin and by a prominent intertwine of epidermal rete pegs and long dermal papillae. The epidermal rete pegs are the epithelial extensions that project into the underlying connective tissue in both skin and mucous membranes. The dermal papillae are finger-like projections that help adhesion between the epidermal and dermal layers, as well as providing a larger surface area to nourish
16320-603: 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
16480-422: The late 1940s. Since 1973, some long-finned pilot whales from New England waters were taken and temporarily kept in captivity. Short-finned pilot whales off southern California, Hawaii and Japan have been kept in aquariums and oceanariums . Several pilot whales from southern California and Hawaii were taken into captivity during the 1960s and early 1970s, two of which were placed at SeaWorld San Diego . During
16640-613: The lips are oil-filled organs called dorsal bursae that have been suggested to be homologous to the sperm whale's spermaceti organ. High-frequency clicks pass through the sound-modifying organs of the extramandibular fat body, intramandibular fat body and the melon . This melon consists of fat, and the skull of any such creature containing a melon will have a large depression. This allows dolphins to use echolocation for orientation. Though most dolphins do not have hair, they do have hair follicles that may perform some sensory function. Beyond locating an object, echolocation also provides
16800-408: The lungs. Dolphins have rather small, unidentifiable spouts. All dolphins have a thick layer of blubber , thickness varying on climate. This blubber can help with buoyancy, protection to some extent as predators would have a hard time getting through a thick layer of fat, and energy for leaner times; the primary usage for blubber is insulation from the harsh climate. Calves, generally, are born with
16960-411: The main food, but the false killer whale and the orca also feed on other marine mammals. Orcas on occasion also hunt whale species larger than themselves. Different breeds of dolphins vary widely in the number of teeth they possess. The orca usually carries 40–56 teeth while the popular bottlenose dolphin has anywhere from 72 to 116 conical teeth and its smaller cousin the common dolphin has 188–268 teeth:
17120-404: The males are larger than females. They have streamlined muscular bodies and two limbs that are modified into flippers. Though not quite as flexible as seals , some dolphins can travel at speeds 29 km/h (18 mph) for short distances. Most delphinids primarily eat fish, along with a smaller number of squid and small crustaceans, but some species specialise in eating squid, or, in the case of
17280-471: The meat of a dolphin which died of natural causes, which would likely be highly undesirable (and potentially dangerous). Various fishing methods, like seine fishing for tuna and the use of drift and gill nets , unintentionally kill many oceanic dolphins. Accidental bycatch in gill nets is common and poses a risk for mainly local dolphin populations. Dolphin safe labels attempt to reassure consumers that fish and other marine products have been caught in
17440-426: The mirror test. In some parts of the world, such as Taiji, Japan and the Faroe Islands , dolphins are traditionally considered as food, and are killed in harpoon or drive hunts . Dolphin meat is consumed in a small number of countries worldwide, which include Japan and Peru (where it is referred to as chancho marino , or "sea pork"). Dolphin meat is dense and such a dark shade of red as to appear black. Fat
17600-437: The mirror test. Some researchers have argued that evidence for self-awareness has not been convincingly demonstrated. Dolphins are highly social animals, often living in pods of up to a dozen individuals, though pod sizes and structures vary greatly between species and locations. In places with a high abundance of food, pods can merge temporarily, forming a superpod ; such groupings may exceed 1,000 dolphins. Membership in pods
17760-447: The most common stranders . Because of their strong social bonds, whole groups of pilot whales will strand. Single stranders have been recorded and these are usually diseased. Group stranding tends to be of mostly healthy individuals. Several hypotheses have been proposed to explain group strandings. When using magnetic fields for navigation, the whales have been suggested to get perplexed by geomagnetic anomalies or they may be following
17920-821: The most common illness was an upper respiratory tract infection . Both species live in groups of 10–30, but some groups may number 100 or more. Data suggest the social structures of pilot whale pods are similar to those of " resident " killer whales. The pods are highly stable and the members have close matrilineal relationships. Pod members are of various age and sex classes, although adult females tend to outnumber adult males. They have been observed making various kin-directed behaviors, such as providing food. Numerous pods will temporarily gather, perhaps to allow individuals from different pods to interact and mate, as well as provide protection. Both species are loosely polygynous . Data suggest both males and females remain in their mother's pod for life; despite this, inbreeding within
18080-502: The nature and extent of that ability is not known. The clicks are directional and are for echolocation, often occurring in a short series called a click train. The click rate increases when approaching an object of interest. Dolphin echolocation clicks are amongst the loudest sounds made by marine animals . Bottlenose dolphins have been found to have signature whistles. These whistles are used in order for dolphins to communicate with one another by identifying an individual. It can be seen as
18240-421: The neck vertebrae, while increasing stability when swimming at high speeds, decreases flexibility, which means they are unable to turn their heads. Oceanic dolphins swim by moving their tail fin and rear body vertically, while their flippers are mainly used for steering. Some species log out of the water, which may allow them to travel faster. Their skeletal anatomy allows them to be fast swimmers. All species have
18400-410: The number of teeth that an individual carries varies widely between within a single species. Hybrids between common and bottlenose bred in captivity had a number of teeth intermediate between that of their parents. One common feeding method is herding, where a pod squeezes a school of fish into a small volume, known as a bait ball . Individual members then take turns plowing through the ball, feeding on
18560-404: The object or animal along using various parts of the body, passing it along to other members of the group or taking it from another member, or throwing it out of the water. Dolphins have also been observed harassing animals in other ways, for example by dragging birds underwater without showing any intent to eat them. Playful behaviour that involves another animal species with active participation of
18720-581: The older whales back out to sea. In September 2022, nearly 200 pilot whales died after becoming stranded on Ocean Beach, part of Tasmania's west coast. Authorities said only about 35 survived of the 230 that were stranded. The IUCN lists long-finned pilot whales as "least concern" in the Red List of Threatened Species . Long-finned pilot whales in the North and Baltic Seas are listed in Appendix II of
18880-401: The only truly dolphin-safe tuna. Loud underwater noises, such as those resulting from naval sonar use, live firing exercises, and certain offshore construction projects such as wind farms , may be harmful to dolphins, increasing stress, damaging hearing, and causing decompression sickness by forcing them to surface too quickly to escape the noise. The renewed popularity of dolphins in
19040-489: The orca, also eat marine mammals and birds. All, however, are purely carnivorous . They typically have between 100 and 200 teeth, although a few species have considerably fewer. Delphinids travel in large pods, which may number a thousand individuals in some species. Each pod forages over a range of tens to hundreds of square kilometres. Some pods have a loose social structure, with individuals frequently joining or leaving, but others seem to be more permanent, perhaps dominated by
19200-690: The orca, in comparison, can travel at speeds up to 55.5 km/h (34.5 mph). A study of a Pacific white-sided dolphin in an aquarium found fast burst acceleration, with the individual being able with 5 strokes (2.5 fluke beats) to go from 5.0 m s-1 to 8.7 m s-1 in 0.7 seconds. The fusing of the neck vertebrae, while increasing stability when swimming at high speeds, decreases flexibility, which means most dolphins are unable to turn their heads. River dolphins have non-fused neck vertebrae and can turn their heads up to 90°. Dolphins swim by moving their fluke and rear body vertically, while their flippers are mainly used for steering. Some species porpoise out of
19360-578: The other animal can also be observed, however. Playful human interaction with dolphins is one example, but playful interactions have been observed in the wild with a number of other species as well, including humpback whales and dogs . Oceanic dolphins are known to teach, learn, cooperate, scheme, and grieve. The neocortex of many species is home to elongated spindle neurons that, prior to 2007, were known only in hominids. In humans, these cells are involved in social conduct, emotions, judgment, and theory of mind. Cetacean spindle neurons are found in areas of
19520-487: The other at SeaWorld San Diego . Orca 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 orca being held in aquaria as of 2012. The orca's intelligence , trainability, striking appearance, playfulness in captivity and sheer size have made it a popular exhibit at aquaria and aquatic theme parks. From 1976 to 1997, 55 whales were taken from
19680-403: The outer ear to the middle ear, dolphins receive sound through the throat, from which it passes through a low-impedance fat-filled cavity to the inner ear. The dolphin ear is acoustically isolated from the skull by air-filled sinus pockets, which allow for greater directional hearing underwater. Dolphins send out high frequency clicks from an organ known as a melon . This melon consists of fat, and
19840-478: The poet Arion from drowning and carried him safe to land, at Cape Matapan , a promontory forming the southernmost point of the Peloponnesus . There was a temple to Poseidon and a statue of Arion riding the dolphin. Dionysus was once captured by Etruscan pirates who mistook him for a wealthy prince they could ransom. After the ship set sail Dionysus invoked his divine powers, causing vines to overgrow
20000-425: The predecessors of modern whales, stretching back to their first ancestor that spent their lives near (rarely in) the water. Likewise, the archaeocetes can be anywhere from near fully terrestrial, to semi-aquatic to fully aquatic, but what defines an archaeocete is the presence of visible legs or asymmetrical teeth. Their features became adapted for living in the marine environment . Major anatomical changes include
20160-488: 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 . The animals were named "pilot whales" because pods were believed to be "piloted" by
20320-451: The ruined palace at Knossos . Dolphins are common in Greek mythology , and many coins from ancient Greece have been found which feature a man, a boy or a deity riding on the back of a dolphin. The Ancient Greeks welcomed dolphins; spotting dolphins riding in a ship's wake was considered a good omen. In both ancient and later art, Cupid is often shown riding a dolphin . A dolphin rescued
20480-429: The same depth. When they reach the end of their dives, pilot whales will sprint, possibly to catch prey, and then make a few buzzes. This is unusual, considering that deep-diving, breath-holding animals would be expected to swim slowly to conserve oxygen. The animal's high metabolism possibly allows it to sprint at deep depths, which would also give it shorter diving periods than some other marine mammals. This may also be
20640-425: The same diet as dolphins and are therefore not competitors for food supplies. The Cornwall Wildlife Trust records about one such death a year. Possible explanations include misdirected infanticide, misdirected sexual aggression or play behaviour . Dolphin copulation happens belly to belly; though many species engage in lengthy foreplay , the actual act is usually brief, but may be repeated several times within
20800-540: The same direction. In loafing groups, whales number between 12 and 30 individuals resting. Mating and other behaviors may take place. Pilot whales have one of the longest birth intervals of the cetaceans, calving once every three to five years. Most matings and calvings occur during the summer for long-finned pilot whales. For short-finned pilot whales of the Southern Hemisphere, births are at their highest in spring and autumn, while in Northern Hemisphere,
20960-586: The second largest brain mass of any animal on earth, next to the sperm whale . The brain to body mass ratio in some is second only to humans. Self-awareness is seen, by some, to be a sign of highly developed, abstract thinking. Self-awareness, though not well-defined scientifically, is believed to be the precursor to more advanced processes like meta-cognitive reasoning (thinking about thinking) that are typical of humans. Research in this field has suggested that cetaceans, among others, possess self-awareness. The most widely used test for self-awareness in animals
21120-512: The ship where the mast and sails had been. He turned the oars into serpents, so terrifying the sailors that they jumped overboard, but Dionysus took pity on them and transformed them into dolphins so that they would spend their lives providing help for those in need. Dolphins were also the messengers of Poseidon and sometimes did errands for him as well. Dolphins were sacred to both Aphrodite and Apollo . Dolphins are sometimes used as symbols, for instance in heraldry. When heraldry developed in
21280-695: The short-finned pilot whale with its 7–9 teeth in each row and flippers one-sixth of total body length. Studies of whales in the Atlantic showed much overlap in these characteristics between the species, making them clines instead of distinctive features. Thus, biologists have since used skull differences to distinguish the two species. The size and weight depend on the species, as long-finned pilot whales are generally larger than short-finned pilot whales. Their lifespans are about 45 years in males and 60 years in females for both species. Both species exhibit sexual dimorphism . Adult long-finned pilot whales reach
21440-449: The short-finned pilot whale, females become sexually mature at 9 years old and males at about 13–16 years. For the long-finned pilot whale, females reach maturity at around eight years and males at around 12 years. Pilot whales emit echolocation clicks for foraging and whistles and burst pulses as social signals (e.g. to keep contact with members of their pod). With active behavior, vocalizations are more complex, while less-active behavior
21600-486: The shrinking and eventual disappearance of the hind limbs which took place with the first odontocetes and mysticetes 34 million years ago. The modern dolphin skeleton has two small, rod-shaped pelvic bones thought to be vestigial hind limbs. In October 2006, an unusual bottlenose dolphin was captured in Japan; it had small fins on each side of its genital slit, which scientists believe to be an unusually pronounced development of these vestigial hind limbs. Today,
21760-403: The sides of its head. Several species exhibit sexual dimorphism, with the males being larger than the females. Breathing involves expelling stale air from the blowhole , forming an upward, steamy spout, followed by inhaling fresh air into the lungs; a spout only occurs when the warm air from the lungs meets the cold external air, so it may only form in colder climates. All oceanic dolphins have
21920-473: The skeleton that the whale had a large beak. The long-finned pilot whale was first classified by Thomas Stewart Traill in 1809 as Delphinus melas . Its scientific name was eventually changed to Globicephala melaena . Since 1986, the specific name of the long-finned pilot whale was changed to its original form melas . Other species classifications have been proposed but only two have been accepted. There exist geographic forms of short-finned pilot whales off
22080-507: The skin to keep warm in the cold water. Although oceanic dolphins are widespread, most species prefer the warmer waters of the tropic zones, but some, like the right whale dolphin , prefer colder climates. Some have a global distribution, like the orca. Oceanic dolphins feed largely on fish and squid, but a few, like the orca, feed on large mammals, like seals. Male dolphins typically mate with multiple females every year, but females only mate every two to three years. Calves are typically born in
22240-440: The skull of any such creature containing a melon will have a large depression. This allows dolphins to produce biosonar for orientation. Though most dolphins do not have hair, they do have hair follicles that may perform some sensory function. Beyond locating an object, echolocation also provides the animal with an idea on an object's shape and size, though how exactly this works is not yet understood. The eye of oceanic dolphins
22400-456: The south. These fisheries were at their highest in the late 1940s and early 1950s; 2,326 short-finned pilot whales were harvested in the mid- to late 1980s. This had decreased to about 400 per year by the 1990s. Pilot whales have also fallen victim to bycatches . In one year, around 30 short-finned pilot whales were caught by the squid round-haul fishery in southern California. Likewise, California's drift gill net fishery took around 20 whales
22560-609: The southern coast of Australia have been observed to mimic the calls of orcas while scavenging for food. This behaviour is thought to deter orca pods from approaching the pilot whales. Pilot whales have been occasionally observed mobbing or chasing other species of cetaceans. In several parts of the world, including off Iceland, long-finned pilot whales have been frequently documented chasing killer whales. The reasons for these chases are unknown, but it has been proposed that they might be due to either competition for prey or an anti-predation strategy. In 2021 an adult female killer whale with
22720-576: The spring and summer, and females bear all the responsibility for raising them. Mothers of some species fast and nurse their young for relatively long times. Dolphins produce a variety of vocalizations, usually in the form of clicks and whistles. Oceanic dolphins are sometimes hunted in places such as Japan, in an activity known as dolphin drive hunting . Besides drive hunting, they also face threats from bycatch , habitat loss, and marine pollution . Dolphins have been depicted in various cultures worldwide. They occasionally feature in literature and film, as in
22880-430: The stunned fish. Corralling is a method where dolphins chase fish into shallow water to catch them more easily. Orcas and bottlenose dolphins have also been known to drive their prey onto a beach to feed on it, a behaviour known as beach or strand feeding. Some species also whack fish with their flukes, stunning them and sometimes knocking them out of the water. Reports of cooperative human-dolphin fishing date back to
23040-410: The subcutaneous blubber or fat depends on the dolphin's health, development, location, reproductive state, and how well it feeds. This fat is thickest on the dolphin's back and belly. Most of the dolphin's body fat is accumulated in a thick layer of blubber. Blubber differs from fat in that, in addition to fat cells, it contains a fibrous network of connective tissue. The blubber functions to streamline
23200-576: The superfamily Delphinoidea , which also includes the porpoises (Phocoenidae) and the Monodontidae ( beluga whale and narwhal ). River dolphins are relatives of the Delphinoidea. Oceanic dolphins range in size from the 1.7-metre-long (5 ft 7 in) and 50-kilogram (110-pound) Maui's dolphin to the 9.4-metre (31 ft) and 10-metric-ton (11-short-ton) orca , the largest known dolphin. Several species exhibit sexual dimorphism ;
23360-526: The survival of the other pod members. No evidence of "bachelor" groups has been found. Pilot whale pods off southern California have been observed in three different groups: traveling/hunting groups, feeding groups and loafing groups. In traveling/hunting groups, individuals position themselves in chorus lines stretching two miles long, with only a few whales underneath. Sexual and age-class segregation apparently occurs in these groups. In feeding groups, individuals are very loosely associated, but may move in
23520-634: The swimmers or charging the sharks to make them go away. Dolphins communicate using a variety of clicks, whistle-like sounds and other vocalizations. Dolphins also use nonverbal communication by means of touch and posturing . Dolphins also display culture, something long believed to be unique to humans (and possibly other primate species). In May 2005, a discovery in Australia found Indo-Pacific bottlenose dolphins ( Tursiops aduncus ) teaching their young to use tools. They cover their snouts with sponges to protect them while foraging. This knowledge
23680-428: The temperature drops, the blubber constricts the blood vessels to reduce blood flow in the dolphin. This allows the dolphin to spend less energy heating its own body, ultimately keeping the animal warmer without burning energy as quick. In order to release heat, the heat must pass the blubber layer. There are thermal windows that lack blubber, are not fully insulated and are somewhat thin and highly vascularized, including
23840-402: The time in which calving peaks can vary by population. For long-finned pilot whales, gestation lasts 12–16 months, and short-finned pilot whales have a 15-month gestation period. The calf nurses for 36–42 months, allowing for extensive mother-calf bonds. Young pilot whales will take milk until as old as 13–15 years of age. Short-finned pilot whale females will go through menopause , but this
24000-403: The two species of hippo. Dolphins have torpedo-shaped bodies with generally non-flexible necks, limbs modified into flippers, a tail fin, and bulbous heads. Dolphin skulls have small eye orbits, long snouts, and eyes placed on the sides of its head; they lack external ear flaps. Dolphins range in size from the 1.7 m (5 ft 7 in) long and 50 kg (110 lb) Maui's dolphin to
24160-464: The underside toward the head, a dorsal fin , and a tail fin. These flippers contain four digits. Although oceanic dolphins do not possess fully developed hind limbs, some possess discrete rudimentary appendages, which may contain feet and digits. Oceanic dolphins are fast swimmers in comparison to seals who typically cruise at 11–27 km/h (7–17 mph); the orca, in comparison, can travel at speeds of up to 55.5 km/h (34.5 mph). The fusing of
24320-435: The water, which allows them to travel faster. Their skeletal anatomy allows them to be fast swimmers. All species have a dorsal fin to prevent themselves from involuntarily spinning in the water. Some dolphins are adapted for diving to great depths. In addition to their streamlined bodies, some can selectively slow their heart rate to conserve oxygen. Some can also re-route blood from tissue tolerant of water pressure to
24480-421: The water. Oceanic dolphins are capable of making a broad range of sounds using nasal airsacs located just below the blowhole. Roughly three categories of sounds can be identified: frequency modulated whistles, burst-pulsed sounds, and clicks. Dolphins communicate with whistle-like sounds produced by vibrating connective tissue, similar to the way human vocal cords function, and through burst-pulsed sounds, though
24640-664: The waters of the shelf break and slope . Once commonly seen off of Southern California, short-finned pilot whales disappeared from the area after a strong El Niño year in the early 1980s, according to the National Oceanic and Atmospheric Administration . In October 2014, crew and passengers on several boats spotted a pod of 50–200 off Dana Point, California . Although pilot whales are not known to have many predators, possible threats come from humans and killer whales. Both species eat primarily squid . The whales make seasonal inshore and offshore movements in response to
24800-516: The west coast of the US have had high amounts of DDT and PCB in contrast to the low amounts found in whales from Japan and the Antilles. Pilot whale meat is available for consumption in very few areas of Japan , mainly along the central Pacific coast, and also in other areas of the world, such as the Faroe Islands. The meat is high in protein (higher than beef) and low in fat. Because a whale's fat
24960-445: The whales found along Vancouver Island and northern USA coasts, has indicated that the geniture of this form could be caused by the extinction of long-finned pilots in north Pacific in the 12th century, where Magondou , the smaller, southern type possibly filled the former niches of long-finned pilots, adapting and colonizing into colder waters. Pilot whales are mostly dark grey, brown, or black, but have some light areas such as
25120-452: The whistle development of each dolphin. Dolphins are able to communicate to one another by addressing another dolphin through mimicking their whistle. The signature whistle of a male bottlenose dolphin tends to be similar to that of his mother, while the signature whistle of a female bottlenose dolphin tends to be more distinguishable. Bottlenose dolphins have a strong memory when it comes to these signature whistles, as they are able to relate to
25280-573: The wild in Iceland, 19 in Japan and three in Argentina. These figures exclude animals that died during capture. Live captures fell dramatically in the 1990s, and by 1999, about 40% of the 48 animals on display in the world were captive-born. In Greek myths , they were seen invariably as helpers of humankind. Dolphins also seem to have been important to the Minoans , judging by artistic evidence from
25440-577: The world or have been reported in the wild, such as a bottlenose- Atlantic spotted hybrid. The best known hybrid is the wholphin , a false killer whale-bottlenose dolphin hybrid. The wolphin is a fertile hybrid. Two wolphins currently live at the Sea Life Park in Hawaii; the first was born in 1985 from a male false killer whale and a female bottlenose. Wolphins have also been observed in the wild. Dolphins are descendants of land-dwelling mammals of
25600-425: The ⅔ or ¾ exponent of the body mass. Comparison of a particular animal's brain size with the expected brain size based on such allometric analysis provides an encephalization quotient that can be used as another indication of animal intelligence. Orca have the second largest brain mass of any animal on earth, next to the sperm whale . The brain to body mass ratio in some is second only to humans. Self-awareness
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