Adolphinis anaquatic mammalin thecladeOdontoceti (toothed whale). Dolphins belong to the familiesDelphinidae(the oceanic dolphins),Platanistidae(the Indianriver dolphins),Iniidae(the New World river dolphins),Pontoporiidae(thebrackishdolphins), and possibly extinctLipotidae(baiji or Chinese river dolphin). There are 40extant speciesnamed as dolphins.
Dolphins range in size from the 1.7-metre-long (5 ft 7 in) and 50-kilogram (110-pound)Maui's dolphinto the 9.5 m (31 ft) and 10-tonne (11-short-ton)orca.Various species of dolphins exhibitsexual dimorphismwhere the males are larger than females. They have streamlined bodies and two limbs that are modified into flippers. Though not quite as flexible asseals,they are faster; some dolphins can briefly travel at speeds of 29 kilometres per hour (18 mph) or leap about 9 metres (30 ft).[1]Dolphins use their conical teeth to capture fast-movingprey.They have well-developed hearing which 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, orblubber,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 theright whale dolphin,prefer colder climates. Dolphins feed largely on fish and squid, but 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 the form of clicks and whistles.
Dolphins are sometimes hunted in places such as Japan, in an activity known asdolphin drive hunting.Besides drive hunting, they also face threats frombycatch,habitat loss, andmarine 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 is thebottlenose dolphin,while there are around 60orcas in captivity.
Etymology
The name is originally fromGreekδελφίς(delphís), "dolphin",[2]which was related to the Greekδελφύς(delphus), "womb".[2]The animal's name can therefore be interpreted as meaning "a 'fish' with a womb".[3]The name was transmitted via theLatindelphinus[4](theromanizationof the later Greek δελφῖνος –delphinos[2]), which inMedieval Latinbecamedolfinusand inOld Frenchdaulphin,which reintroduced thephinto the worddolphin.The termmereswine( "sea pig" ) is also used.[5][6]
The termdolphincan be used to refer to most species in the familyDelphinidae(oceanic dolphins) and the river dolphin families ofIniidae(South American river dolphins), Pontoporiidae (La Plata dolphin),Lipotidae(Yangtze river dolphin) andPlatanistidae(Ganges river dolphin and Indus river dolphin).[7][8]Meanwhile, themahi-mahifish is called the dolphinfish.[9]In common usage, the termwhaleis used only for the larger cetacean species,[10]while the smaller ones with a beaked or longer nose are considered dolphins.[11]The namedolphinis used casually as a synonym forbottlenose dolphin,the most common and familiar species of dolphin.[12]There are six species of dolphins commonly thought of as whales, collectively known asblackfish:theorca,themelon-headed whale,thepygmy killer whale,thefalse killer whale,and the two species ofpilot whales,all of which are classified under the family Delphinidae and qualify as dolphins.[13]Although the termsdolphinandporpoiseare sometimes used interchangeably,porpoiseusually refers to the Phocoenidae family, which have a shorter beak and spade-shaped teeth and differ in their behavior.[12]
A group of dolphins is called aschoolor apod.Male dolphins are calledbulls,females are calledcowsand young dolphins are calledcalves.[14]
Hybridization
In 1933, three hybrid dolphins beached off the Irish coast; they werehybridsbetweenRisso'sand bottlenose dolphins.[15]This mating was later repeated in captivity, producing a hybrid calf. In captivity, a bottlenose and arough-toothed dolphinproduced hybrid offspring.[16]A common-bottlenose hybrid lives atSeaWorldCalifornia.[17]Other dolphin hybrids live in captivity around the world or have been reported in the wild, such as a bottlenose-Atlantic spottedhybrid.[18]The best known hybrid is thewholphin,a false killer whale-bottlenose dolphin hybrid. The wolphin is a fertile hybrid. Two wolphins currently live at theSea Life Parkin 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.[19]
Evolution
Dolphins are descendants of land-dwelling mammals of theartiodactylorder(even-toed ungulates). They are related to theIndohyus,an extinctchevrotain-like ungulate, from which they split approximately 48 million years ago.[20][21]
The primitive cetaceans, orarchaeocetes,first took to the sea approximately 49 million years ago and became fully aquatic by 5–10 million years later.[22]
Archaeocetiis a parvorder comprising ancient whales. These ancient whales are 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.[23][24][25][26]Their features became adapted for living in themarine environment.Major anatomical changes include the hearing set-up that channeled vibrations from the jaw to the earbone which occurred withAmbulocetus49 million years ago, astreamliningof the body and the growth of flukes on the tail which occurred around 43 million years ago withProtocetus,the migration of the nasal openings toward the top of thecraniumand the modification of the forelimbs into flippers which occurred withBasilosaurus35 million years ago, and the shrinking and eventual disappearance of the hind limbs which took place with the first odontocetes and mysticetes 34 million years ago.[27][28][29]The modern dolphinskeletonhas two small, rod-shaped pelvic bones thought to bevestigialhind limbs. In October 2006, an unusual bottlenose dolphin was captured in Japan; it had smallfinson each side of its genital slit, which scientists believe to be an unusually pronounced development of these vestigial hind limbs.[30]
Today, the closest living relatives of cetaceans are thehippopotamuses;these share a semi-aquatic ancestor that branched off from other artiodactyls some 60 million years ago.[31]Around 40 million years ago, a common ancestor between the two branched off into cetacea andanthracotheres;anthracotheres became extinct at the end of the Pleistocene two-and-a-half million years ago, eventually leaving only one surviving lineage: the two species of hippo.[32][33]
Anatomy
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 dolphinto the 9.5 m (31 ft 2 in) and 10 t (11 short tons)orca.Overall, they tend to be dwarfed by otherCetartiodactyls.Several species have female-biased sexual dimorphism, with the females being larger than the males.[34][35]
Dolphins have conical teeth, as opposed toporpoises' spade-shaped teeth. These conical teeth are used to catch swift prey such as fish, squid or large mammals, such as seals.[35]
Breathing involves expelling stale air from theirblowhole,in an upward blast, which may be visible in cold air, followed by inhaling fresh air into the lungs. Dolphins have rather small, unidentifiable spouts.[35][36]
All dolphins have a thick layer ofblubber,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 a thin layer of blubber, which develops at different paces depending on the habitat.[35][37]
Dolphins have a two-chambered stomach that is similar in structure to terrestrial carnivores. They havefundicandpyloricchambers.[38]
Dolphins' reproductive organs are located inside the body, with genital slits on the ventral (belly) side. Males have two slits, one concealing thepenisand one further behind for theanus.[39]Females have one genital slit, housing thevaginaand the anus, with amammary sliton either side.[40][41][42]
Integumentary system
The integumentary system is an organ system mostly consisted of skin, hair, nails and endocrine glands. The skin of dolphins is very important as it is specialized to satisfy specific requirements. Some of these requirements include protection, fat storage, heat regulation, and sensory perception. The skin of a dolphin is made up of two parts: the epidermis and the blubber, which consists of two layers including the dermis and subcutis.[43]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.[43]Dolphins are a part of the species Cetacea. The epidermis of this species is characterized by the lack of keratin and by a prominent intertwine of epidermalrete pegsand long dermal papillae.[43]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 the epidermal layer.[44]The thickness of a dolphin's epidermis varies, depending on species and age.
Blubber
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.[43]The thickness of 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.[45]
The blubber functions to streamline the body and to form specialized locomotor structures such as the dorsal fin, propulsive fluke blades and caudal keels.[43]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 highlyproprioceptive,which explains sensory perception.[43]Proprioception, which 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.[46]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.[43]The blubber manipulates the blood vessels to help the dolphin stay warm. When the temperature drops, the blubber constricts the blood vessels to reduce blood flow in the dolphin.[47]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 the dorsal fin, flukes, and flippers.[48]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 the extremities, meaning that the heart always has warm blood and it decreases the heat lost to the water in those thermal windows.[48]
Locomotion
Dolphins have two pectoral flippers, each containing four digits, a bonelessdorsal finfor 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); the orca, in comparison, can travel at speeds up to 55.5 km/h (34.5 mph).[citation needed]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.[49]
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.[50][51]River dolphinshave non-fused neck vertebrae and can turn their heads up to 90°.[52]Dolphins swim by moving their fluke and rear body vertically, while their flippers are mainly used for steering. Some speciesporpoiseout of the water, which allows them to travel faster. Their skeletal anatomy allows them to be fast swimmers. All species have adorsal finto prevent themselves from involuntarily spinning in the water.[35][37]
Some dolphins are adapted for diving to great depths. In addition to their streamlined bodies, some can selectively slow theirheart rateto conserve oxygen.[53][54]Some can also re-route blood from tissue tolerant of water pressure to the heart, brain and other organs. Theirhemoglobinandmyoglobinstore oxygen in body tissues, and they have twice as much myoglobin as hemoglobin.[55]
Senses
A dolphin ear has specific adaptations to themarineenvironment. In humans, themiddle earworks as an impedance equalizer between the outside air's lowimpedanceand thecochlearfluid'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 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.[56]
Dolphins generate sounds independently of respiration using recycled air that passes through air sacs and phonic (alternatively monkey) lips. Integral to the lips are oil-filled organs called dorsal bursae that have been suggested to be homologous to the sperm whale's spermaceti organ.[57]High-frequency clicks pass through the sound-modifying organs of the extramandibular fat body, intramandibular fat body and themelon.This melon consists of fat, and the skull of any such creature containing a melon will have a large depression. This allows dolphins to useecholocationfor orientation.[35][58][59][60][61]Though most dolphins do not have hair, they do havehair folliclesthat may perform some sensory function.[62]Beyond locating an object,echolocationalso provides the animal with an idea on an object's shape and size, though how exactly this works is not yet understood.[63]The small hairs on the rostrum of theboto(river dolphins of South America) are believed to function as atactile sense,possibly to compensate for the boto's poor eyesight.[64]
A dolphin eye 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 water's refraction of light. Their eyes contain bothrodandconecells, 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 a more limited capacity for color vision than most mammals.[65]Most dolphins have slightly flattened eyeballs, enlarged pupils (which shrink as they surface to prevent damage), slightly flattened corneas and atapetum 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 the eyelids andouter corneal layerthat act as protection for the cornea.[58]
Theolfactory lobesandnerveare absent in dolphins, suggesting that they have no sense of smell.[58]
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.[58]
Intelligence
Dolphins are known to teach, learn, cooperate, scheme, and grieve.[66]The neocortex of many species is home to elongatedspindle neuronsthat, prior to 2007, were known only in hominids.[67]In humans, these cells are involved in social conduct, emotions, judgment, and theory of mind.[68]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.[69]
Brain sizewas 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.Allometricanalysis indicates that mammalian brain size scales at approximately the ⅔ or ¾ exponent of the body mass.[clarification needed][70]Comparison of a particular animal's brain size with the expected brain size based on such allometric analysis provides anencephalization quotientthat can be used as another indication of animal intelligence.Orcashave the second largest brain mass of any animal on earth, next to thesperm whale.[71]Thebrain to body mass ratioin some is second only to humans.[72]
Self-awarenessis 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 likemeta-cognitive reasoning(thinking about thinking) that are typical of humans. Research in this field has suggested that cetaceans, among others, possess self-awareness.[73] The most widely used test for self-awareness in animals is themirror testin 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.[74]
Some disagree with these findings, arguing that the results of these tests are open to human interpretation and susceptible to theClever Hanseffect. This test 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 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.[74]
In 1995, Marten and Psarakos used television to test dolphin self-awareness.[75]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 the mirror test.[74]Some researchers have argued that evidence for self-awareness has not been convincingly demonstrated.[76]
Behavior
Socialization
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 asuperpod;such groupings may exceed 1,000 dolphins. Membership in pods 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.[77]Thisaltruismdoes not appear to be limited to their own species. The dolphinMokoinNew Zealandhas been observed guiding a femalepygmy sperm whaletogether with her calf out of shallow water where they had stranded several times.[78]They have also been seen protecting swimmers from sharks by swimming circles around the swimmers[79][80]or charging the sharks to make them go away.
Dolphins communicate using a variety of clicks, whistle-like sounds and other vocalizations. Dolphins also usenonverbal communicationby means of touch andposturing.[81]
Dolphins also display culture, something long believed to be unique to humans (and possibly otherprimatespecies). In May 2005, a discovery in Australia foundIndo-Pacific bottlenose dolphins(Tursiops aduncus) teaching their young to use tools. They cover theirsnoutswithspongesto protect them while foraging. This knowledge is mostly transferred by mothers to daughters, unlikesimianprimates, where knowledge is generally passed on to both sexes. Using sponges as mouth protection is a learned behavior.[82]Another learned behavior was discovered among river dolphins in Brazil, where some male dolphins use weeds and sticks as part of a sexual display.[83]
Forms of care-giving between fellows and even for members of different species[84](seeMoko (dolphin)) are recorded in various species – such as trying to save weakened fellows[85]or femalepilot whalesholding up dead calves for long periods.
Dolphins engage in acts of aggression towards each other. The older 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 ininfanticide.Dolphins have also been known to killporpoises(porpicide) for reasons which are not fully understood, as porpoises generally do not share the same diet as dolphins and are therefore not competitors for food supplies.[86][87]TheCornwall Wildlife Trustrecords about one such death a year. Possible explanations include misdirected infanticide, misdirected sexual aggression orplay behaviour.[88]
Reproduction and sexuality
Dolphincopulationhappens belly to belly; though many species engage in lengthyforeplay,the actual act is usually brief, but may be repeated several times within a short timespan.[89]Thegestation periodvaries with species; for the smalltucuxi dolphin,this period is around 11 to 12 months,[90]while for the orca, the gestation period is around 17 months.[91]Typically dolphins give birth to a single calf, which is, unlike most other mammals, born tail first in most cases.[92]They usually become sexually active at a young age, even before reachingsexual maturity.[89]The age of sexual maturity varies by species and sex.[93]
Dolphins are known to displaynon-reproductive sexual behavior,engaging inmasturbation,stimulation of the genital area of other individuals using therostrumor flippers, andhomosexual contact.[89][94][95]
Various species of dolphin have been known to engage in sexual behavior including copulation with dolphins of other species, and occasionally exhibitsexual behavior towards other animals,including humans.[96][97]Sexual encounters may be violent, with male bottlenose dolphins sometimes showing aggressive behavior towards both females and other males.[98]Male dolphins may also work together and attempt to herd females inestrus,keeping the females by their side by means of both physical aggression and intimidation, to increase their chances of reproductive success.[99]
Sleeping
Generally, dolphins sleep with only one brainhemisphereinslow-wave sleepat 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.[100][101][102] In captivity, dolphins seemingly enter 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 kickreflexkeeps the blowhole above the water if necessary.Anesthetizeddolphins initially show a tail kick reflex.[103]Though a similar state has been observed with wildsperm whales,it is not known if dolphins in the wild reach this state.[104]TheIndus river dolphinhas 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.[105]
Feeding
There are various feeding methods among and within 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. Orcas on occasion also hunt whale species larger than themselves.[106]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: 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 abait ball.Individual members then take turns plowing through the ball, feeding on the stunned fish.[106]Corralling is a method where dolphins chase fish into shallow water to catch them more easily.[106]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.[107][108]Some species also whack fish with their flukes, stunning them and sometimes knocking them out of the water.[106]
Reports of cooperative human-dolphin fishing date back to theancient Romanauthor andnatural philosopherPliny the Elder.[109]A modern human-dolphin partnership currently operates inLaguna,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.[110][111]
InShark Bay,Australia, dolphins catch fish by trapping them in hugeconch shells.[112]In "shelling", a dolphin brings the shell to the surface and shakes it, so that fish sheltering within fall into the dolphin's mouth. From 2007 to 2018, in 5,278 encounters with dolphins, researchers observed 19 dolphins shelling 42 times. The behavior spreads mainly within generations, rather than being passed from mother to offspring.
Vocalization
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 modulatedwhistles, burst-pulsed sounds, and clicks. Dolphins communicate with whistle-like sounds produced by vibrating connective tissue, similar to the way human vocal cords function,[113]and through burst-pulsed sounds, though 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 theloudest sounds made by marine animals.[114]
Bottlenose dolphins have been found to have signature whistles, a whistle that is unique to a specific individual. These whistles are used in order for dolphins to communicate with one another by identifying an individual. It can be seen as the dolphin equivalent of a name for humans.[115]These signature whistles are developed during a dolphin's first year; it continues to maintain the same sound throughout its lifetime.[116]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 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 distinguishing.[117]Bottlenose dolphins have a strong memory when it comes to these signature whistles, as they are able to relate to a signature whistle of an individual they have not encountered for over twenty years.[118]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.[119][120][121][122]
Because dolphins are generally associated in groups, communication is necessary. Signal masking is when other similar sounds (conspecific sounds) interfere with the original acoustic sound.[123]In larger groups, individual whistle sounds are less prominent. Dolphins tend to travel in pods, upon which there are groups of dolphins that range from a few to many. Although they are traveling in these pods, the dolphins do not necessarily swim right next to each other. Rather, they swim within the same general vicinity. In order to prevent losing one of their pod members, there are higher whistle rates. Because their group members were spread out, this was done in order to continue traveling together.
Jumping and playing
Dolphins frequently leap above the water surface, this being done for various reasons. When travelling, jumping can save the dolphin energy as there is less friction while in the air.[124]This type of travel is known as porpoising.[124]Other reasons include orientation, social displays, fighting,non-verbal communication,entertainment and attempting to dislodgeparasites.[125][126]
Dolphins show various types of playful behavior, often including objects, self-madebubble rings,other dolphins or other animals.[8][127][128]When playing with objects or small animals, common behavior includes carrying 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.[127]Dolphins have also been observed harassing animals in other ways, for example by dragging birds underwater without showing any intent to eat them.[127]Playful behaviour that involves another animal species with active participation of the other animal has also been observed. Playful dolphin interactions with humans are the most obvious examples, followed by those withhumpback whalesanddogs.[129][130]
Juvenile dolphins off the coast of Western Australia have been observed chasing, capturing, and chewing onblowfish.[131]While some reports state that the dolphins are becoming intoxicated on thetetrodotoxinin the fishes' skin,[132]other reports have characterized this behavior as the normal curiosity and exploration of their environment in which dolphins engage.[133]
Tail-walking
Although this behaviour is highly unusual in wild dolphins, severalIndo-Pacific bottlenose dolphins(Tursiops aduncus) of thePort River,north ofAdelaide,South Australia,have been seen to have exhibit "tail-walking".[134][135]This activity mimicks a standing posture, using the tail to run backwards along the water.[136]To perform this movement, the dolphin "forces the majority of its body vertically out of the water and maintains the position by vigorously pumping its tail".[135]
This started in 1988 when a female named Billie was rescued after becoming trapped in a pollutedmarina,[137]and spent two weeks recuperating with captive dolphins. Billie had previously been observed swimming and frolicking withracehorsesexercising in the Port River in the 1980s. After becoming trapped in a reedy estuary further down the coast, she was rescued and placed with several captive dolphins at a marine park to recuperate. There she observed the captive dolphins performing tail-walking.[136]After being returned to the Port River, she continued to perform this trick, and another dolphin, Wave, copied her. Wave, a very active tail-walker, passed on the skill to her daughters, Ripple and Tallula.[134]
After Billie's premature death, Wave started tail-walking much more frequently, and other dolphins in the group were observed also performing the behaviour.[135]In 2011, up to 12 dolphins were observed tail-walking, but only females appeared to learn the skill.[138]In October 2021, a dolphin was observed tail-walking over a number of hours.[137]
Scientists have found the spread of this behaviour, through up to two generations, surprising, as it brings no apparent advantage, and is very energy-consuming.[138]A 2018 study by Mike Rossley et al. suggested:[134]
Social learning is the most likely mechanism for the introduction and spread of this unusual behaviour, which has no known adaptive function. These observations demonstrate the potential strength of the capacity for spontaneous imitation in bottlenose dolphins, and help explain the origin and spread of foraging specializations observed in multiple populations of this genus.
Threats
Dolphins have few marine enemies. Some species or specific populations have none, making themapex predators.For most of the smaller species of dolphins, only a few of the larger sharks, such as thebull shark,dusky shark,tiger sharkandgreat white shark,are a potential risk, especially for calves.[139]Some of the larger dolphin species, especiallyorcas,may also prey on smaller dolphins, but this seems rare.[140]Dolphins also suffer from a wide variety of diseases and parasites.[141][142]TheCetacean morbillivirusin particular has been known to cause regionalepizooticsoften leaving hundreds of animals of various species dead.[143][144]Symptoms of infection are often a severe combination ofpneumonia,encephalitisand damage to the immune system, which greatly impair the cetacean's ability to swim and stay afloat unassisted.[145][146]A study at the U.S. National Marine Mammal Foundation revealed that dolphins, like humans, develop a natural form oftype 2 diabeteswhich may lead to a better understanding of the disease and new treatments for both humans and dolphins.[147]
Dolphins can tolerate and recover from extreme injuries such assharkbites although the exact methods used to achieve this are not known. Thehealingprocess is rapid and even very deep wounds do not cause dolphins tohemorrhageto death. Furthermore, even gaping wounds restore in such a way that the animal's body shape is restored, and infection of such large wounds seems rare.[148]
A study published in the journalMarine Mammal Sciencesuggests that at least some dolphins survive shark attacks using everything from sophisticated combat moves to teaming up against the shark.[149][150][151]
Humans
Some dolphin species are at risk of extinction, especially some river dolphin species such as the Amazon river dolphin, and theGangesandYangtze river dolphin,which are critically or seriously endangered. A 2006 survey found no individuals of the Yangtze river dolphin. The species now appears to befunctionally extinct.[152]
Pesticides,heavy metals, plastics, and other industrial and agricultural pollutants that do not disintegrate rapidly in the environment concentrate in predators such as dolphins.[153]Injuries or deaths due to collisions with boats, especially theirpropellers,are also common.
Various fishing methods, most notably purseseine fishingfortunaand the use ofdriftandgill nets,unintentionally kill many dolphins.[154]Accidentalby-catchin gill nets and incidental captures in antipredator nets that protect marine fish farms are common and pose a risk for mainly local dolphin populations.[155][156]In some parts of the world, such asTaijiin Japan and theFaroe Islands,dolphins are traditionally considered food and are killed inharpoonordrive hunts.[157]Dolphin meat is high in mercury and may thus pose a health danger to humans when consumed.[158]
Queensland'sshark cullingprogram, which has killed roughly 50,000 sharks since 1962, has also killed thousands of dolphins as bycatch.[159][160]"Shark control" programs in both Queensland andNew South Walesuseshark netsanddrum lines,which entangle and kill dolphins.[161]Queensland's "shark control" program has killed more than 1,000 dolphins in recent years,[160]and at least 32 dolphins have been killed in Queensland since 2014.[162]Ashark cullingprogram inKwaZulu-Natalhas killed at least 2,310 dolphins.[163]
Dolphin safe labelsattempt to reassure consumers that fish and other marine products have been caught in 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 the only truly dolphin-safe tuna.[164] Loud underwater noises, such as those resulting fromnavalsonaruse, live firing exercises, and certainoffshore constructionprojects such aswind farms,may be harmful to dolphins, increasing stress, damaging hearing, and causingdecompression sicknessby forcing them to surface too quickly to escape the noise.[165][166]
Dolphins and other smaller cetaceans are also hunted in an activity known as dolphin drive hunting. This is accomplished by driving a pod together with boats and usually into a bay or onto a beach. Their escape is prevented by closing off the route to the ocean with other boats or nets. Dolphins are hunted this way in several places around the world, including theSolomon Islands,theFaroe Islands,Peru,and Japan, the most well-known practitioner of this method. By numbers, dolphins are mostly hunted for theirmeat,though some end up indolphinariums.Despite the controversial nature of the hunt resulting in international criticism, and the possible health risk that the often polluted meat causes, thousands of dolphins are caught in drive hunts each year.
Impacts of climate change
Dolphins are marine mammals with broad geographic extent, making them susceptible to climate change in various ways. The most common effect of climate change on dolphins is the increasing water temperatures across the globe.[167]This has caused a large variety of dolphin species to experience range shifts, in which the species move from their typical geographic region to cooler waters.[168][169]Another side effect of increasing water temperatures is the increase inharmful algae blooms,which has caused a mass die-off of bottlenose dolphins.[167]
InCalifornia,the 1982–83El Niñowarming event caused the near-bottom spawningmarket squidto leave southern California, which caused their predator, thepilot whale,to also leave. As the market squid returned six years later,Risso's dolphinscame to feed on the squid.Bottlenose dolphinsexpanded their range from southern to central California, and stayed even after the warming event subsided.[168]ThePacific white-sided dolphinhas had a decline in population in the southwestGulf of California,the southern boundary of their distribution. In the 1980s they were abundant with group sizes up to 200 across the entire cool season. Then, in the 2000s, only two groups were recorded with sizes of 20 and 30, and only across the central cool season. This decline was not related to a decline of other marine mammals or prey, so it was concluded to have been caused by climate change as it occurred during a period of warming. Additionally, the Pacific white-sided dolphin had an increase in occurrence on the west coast ofCanadafrom 1984 to 1998.[170]
In theMediterranean,sea surface temperatureshave increased, as well assalinity,upwellingintensity, and sea levels. Because of this, prey resources have been reduced causing a steep decline in theshort-beaked common dolphinMediterranean subpopulation, which was deemed endangered in 2003. This species now only exists in theAlboran Sea,due to its high productivity, distinct ecosystem, and differing conditions from the rest of the Mediterranean.[171]
In northwest Europe, many dolphin species have experienced range shifts from the region's typically colder waters. Warm water dolphins, like the short-beaked common dolphin andstriped dolphin,have expanded north of western Britain and into the northernNorth Sea,even in the winter, which may displace thewhite-beakedandAtlantic white-sided dolphinthat are in that region. The white-beaked dolphin has shown an increase in the southern North Sea since the 1960s because of this. Therough-toothed dolphinandAtlantic spotted dolphinmay move to northwest Europe.[167]In northwestScotland,white-beaked dolphins (local to the colder waters of the North Atlantic) have decreased while common dolphins (local to warmer waters) have increased from 1992 to 2003.[172]Additionally,Fraser's dolphin,found in tropical waters, was recorded in the UK for the first time in 1996.[167]
River dolphinsare highly affected by climate change as high evaporation rates, increased water temperatures, decreased precipitation, and increasedacidificationoccur.[168][173]River dolphins typically have a higher densities when rivers have a lox index of freshwater degradation and better water quality.[173]Specifically looking at theGanges river dolphin,the high evaporation rates and increased flooding on the plains may lead to more human river regulation, decreasing the dolphin population.[168]
As warmer waters lead to a decrease in dolphin prey, this led to other causes of dolphin population decrease. In the case of bottlenose dolphins,mulletpopulations decrease due to increasing water temperatures, which leads to a decrease in the dolphins' health and thus their population.[168]At the Shark Bay World Heritage Area in Western Australia, the localIndo-Pacific bottlenose dolphinpopulation had a significant decline after a marine heatwave in 2011. This heatwave caused a decrease in prey, which led to a decline in dolphin reproductive rates as female dolphins could not get enough nutrients to sustain a calf.[174]The resultant decrease in fish population due to warming waters has also influenced humans to see dolphins as fishing competitors or even bait. Humans usedusky dolphinsas bait or are killed off because they consume the same fish humans eat and sell for profit.[168]In the central Brazilian Amazon alone, approximately 600pink river dolphinsare killed each year to be used as bait.[173]
Relationships with humans
In history and religion
Dolphins have long played a role in human culture.
InGreek myths,dolphins were seen invariably as helpers of humankind. Dolphins also seem to have been important to theMinoans,judging by artistic evidence from the ruined palace atKnossos.During the 2009 excavations of a majorMycenaeancity atIklaina,a striking fragment of a wall painting came to light, depicting a ship with three human figures and dolphins. Dolphins are common inGreek mythology,and many coins fromancient Greecehave been found which feature a man, a boy or a deity riding on the back of a dolphin.[175]TheAncient Greekswelcomed dolphins; spotting dolphins riding in a ship's wake was considered a good omen.[176]In both ancient and later art,Cupidis often shownriding a dolphin.A dolphinrescued the poetArionfrom drowning and carried him safe to land, atCape Matapan,a promontory forming the southernmost point of thePeloponnesus.There was a temple toPoseidonand a statue of Arion riding the dolphin.[177]
The Greeks reimagined thePhoeniciangodMelqartas Melikertês (Melicertes) and made him the son ofAthamasandIno.He drowned but was transfigured as the marine deity Palaemon, while his mother becameLeucothea.(cfIno.) At Corinth, he was so closely connected with the cult of Poseidon that theIsthmian Games,originally instituted in Poseidon's honor, came to be looked upon as the funeral games ofMelicertes.Phalanthuswas another legendary character brought safely to shore (in Italy) on the back of a dolphin, according toPausanias.
Dionysuswas once captured byEtruscanpirateswho mistook him for a wealthy prince they could ransom. After the ship set sail Dionysus invoked his divine powers, causing vines to overgrow 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 andtransformedthem 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 bothAphroditeandApollo.
"Dolfin" was the name of an aristocratic family in the maritimeRepublic of Venice,whose most prominent member was the 13th-centuryDogeGiovanni Dolfin.
InHindu mythologytheGanges river dolphinis associated withGanga,the deity of theGangesriver. The dolphin is said to be among the creatures which heralded the goddess' descent from the heavens and her mount, theMakara,is sometimes depicted as a dolphin.[178]
TheBoto,a species ofriver dolphinthat resides in theAmazon River,are believed to be shapeshifters, orencantados,who are capable of having children with human women.
There are comparatively few surviving myths of dolphins inPolynesiancultures, in spite of their maritime traditions and reverence of other marine animals such assharksandseabirds;unlike these, they are more often perceived as food than as totemic symbols. Dolphins are most clearly represented inRapa NuiRongorongo,and in the traditions of theCaroline Islandsthey are depicted similarly to the Boto, being sexually active shapeshifters.[179]
Heraldry
Dolphins are also used as symbols, for instance in heraldry. When heraldry developed in theMiddle Ages,little was known about the biology of the dolphin and it was often depicted as a sort of fish. Thestylised heraldic dolphinstill conventionally follows this tradition, sometimes showing the dolphin skin covered withfish scales.
A well-known historical example was the coat of arms of the former province of theDauphinéin southern France, from which were derived the arms and the title of theDauphin of France,the heir to the former throne of France (the title literally meaning "The Dolphin of France" ).
Dolphins are present in thecoat of arms of Anguillaand thecoat of arms of Romania,[180]and thecoat of arms of Barbadoshas a dolphinsupporter.[181][182]
Thecoat of arms of the town of Poole,Dorset, England, first recorded in 1563, includes a dolphin, which was historically depicted in stylised heraldic form, but which since 1976 has been depicted naturalistically.[183]
In captivity
Species
The renewed popularity of dolphins in the 1960s resulted in the appearance of manydolphinariaaround the world, making dolphins accessible to the public. Criticism andanimal welfarelaws forced many to close, although hundreds still exist around the world. In the United States, the best known are theSeaWorldmarine mammal parks. In the Middle East the best known areDolphin BayatAtlantis, The Palm[184]and theDubai Dolphinarium.[185]
Various species of dolphins are kept in captivity. These small cetaceans are more often than not kept in theme parks, such asSeaWorld,commonly known as adolphinarium.Bottlenose dolphinsare 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 arespotted dolphins,false killer whalesandcommon dolphins,Commerson's dolphins,as well asrough-toothed dolphins,but all in much lower numbers than the bottlenose dolphin. There are also fewer than tenpilot whales,Amazon river dolphins,Risso's dolphins,spinner dolphins,ortucuxiin captivity.[186]An unusual and very rarehybriddolphin, known as awolphin,is kept at the Sea Life Park in Hawaii, which is a cross between a bottlenose dolphin and afalse killer whale.[187]
The number oforcaskept in captivity is very small, especially when compared to the number of bottlenose dolphins, with 60captive orcasbeing held in aquaria as of 2017[update].[188]The orca'sintelligence,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 the wild in Iceland, 19 from Japan, and three from 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.[37]
Organizations such as theMote Marine Laboratoryrescue andrehabilitatesick, wounded, stranded or orphaned dolphins while others, such as theWhale and Dolphin ConservationandHong Kong Dolphin Conservation Society,work on dolphin conservation and welfare.Indiahas declared the dolphin as its national aquatic animal in an attempt to protect theendangeredGanges river dolphin.TheVikramshila Gangetic Dolphin Sanctuaryhas been created in theGangesriver for the protection of the animals.[189]
Controversy
There is debate over the welfare of cetaceans in captivity, and often welfare can vary greatly dependent on the levels of care being provided at a particular facility. In the United States, facilities are regularly inspected by federal agencies to ensure that a high standard of welfare is maintained.[citation needed]Additionally, facilities can apply to become accredited by the Association of Zoos and Aquariums (AZA), which (for accreditation) requires "the highest standards of animal care and welfare in the world" to be achieved. Facilities such as SeaWorld and the Georgia Aquarium are accredited by the AZA. Organizations such asWorld Animal Protectionand theWhale and Dolphin Conservationcampaign against the practice of keeping them in captivity. In captivity, they often develop pathologies, such as thedorsal fincollapse seen in 60–90% of male orca. Captives have vastly reduced life expectancies, on average only living into their 20s, although there are examples of orcas living longer, including several over 30 years old, and two captive orcas, Corky II and Lolita, are in their mid-40s. In the wild, females who survive infancy live 46 years on average, and up to 70–80 years in rare cases. Wild males who survive infancy live 31 years on average, and up to 50–60 years.
[190]Captivity usually bears little resemblance to wild habitat, and captive whales' social groups are foreign to those found in the wild. Critics claim captive life is stressful due to these factors and the requirement to perform circus tricks that are not part of wild orca behavior. Wild orcas may travel up to 160 kilometres (100 mi) in a day, and critics say the animals are too big and intelligent to be suitable for captivity.[191]Captives occasionally act aggressively towards themselves, their tankmates, or humans, which critics say is a result ofstress.[192]
Although dolphins generally interact well with humans, some attacks have occurred, most of them resulting in small injuries.[193]Orcas,the largest species of dolphin, have been involved in fatalattacks on humansin captivity. The record-holder of documented orca fatal attacks is a male namedTilikum,[194][195][196]who lived atSeaWorldfrom 1992 until his death in 2017.[197]Tilikum has played a role in the death of three people in three different incidents (1991, 1999 and 2010).[198]Tilikum's behaviour sparked the production of the documentaryBlackfish,which focuses on the consequences of keeping orcas in captivity. There are documented incidents in the wild, too, but none of them fatal.[199]
Fatal attacks from other species are less common, but there is a registered occurrence off the coast ofBrazilin 1994, when a man died after being attacked by abottlenose dolphinnamedTião.[200][201]Tiãohad suffered harassment by human visitors, including attempts to stick ice cream sticks down hisblowhole.[202]Non-fatal incidents occur more frequently, both in the wild and in captivity.
While dolphin attacks occur far less frequently than attacks by other sea animals, such assharks,some scientists are worried about the careless programs of human-dolphin interaction. Dr. Andrew J. Read, a biologist at the Duke University Marine Laboratory who studies dolphin attacks, points out that dolphins are large and wild predators, so people should be more careful when they interact with them.[193]
Several scientists who have researched dolphin behaviour have proposed that dolphins' unusually high intelligence in comparison to other animals means that dolphins should be seen asnon-human personswho should have their own specific rights and that it ismorallyunacceptable to keep them captive for entertainment purposes or to kill them either intentionally for consumption or unintentionally as by-catch.[203][204]Four countries –Chile,Costa Rica,Hungary,andIndia– have declared dolphins to be "non-human persons" and have banned the capture and import of live dolphins for entertainment.[205][206][207]
Military
A number of militaries have employed dolphins for various purposes from finding mines to rescuing lost or trapped humans. Themilitary use of dolphinsdrew scrutiny during the Vietnam War, when rumors circulated that theUnited States Navywas training dolphins to kill Vietnamese divers.[208]The United States Navy denies that at any point dolphins were trained for combat. Dolphins are still being trained by the United States Navy for other tasks as part of theU.S. Navy Marine Mammal Program.The Russian military is believed to have closed its marine mammal program in the early 1990s. In 2000 the press reported that dolphins trained to kill by theSoviet Navyhad been sold toIran.[209]
The military is also interested in disguising underwater communications as artificial dolphin clicks.[210]
Therapy
Dolphins are an increasingly popular choice ofanimal-assisted therapyfor psychological problems and developmental disabilities. For example, a 2005 study found dolphins an effective treatment for mild to moderate depression.[211]This study was criticized on several grounds, including a lack of knowledge on whether dolphins are more effective than common pets.[212]Reviewsof this and other published dolphin-assisted therapy (DAT) studies have found important methodological flaws and have concluded that there is no compelling scientific evidence that DAT is a legitimate therapy or that it affords more than fleeting mood improvement.[213]
Consumption
Cuisine
In some parts of the world, such asTaiji, Japanand theFaroe Islands,dolphins are traditionally considered as food, and are killed inharpoonordrive hunts.[157] Dolphin meat is consumed in a small number of countries worldwide, which include Japan[214]andPeru(where it is referred to aschancho marino,or "sea pork" ).[215]While Japan may be the best-known and most controversial example, only a very small minority of the population has ever sampled it.[216]
Dolphin meat is dense and such a dark shade of red as to appear black. Fat is located in a layer ofblubberbetween the meat and the skin. When dolphin meat is eaten in Japan, it is often cut into thin strips and eaten raw assashimi,garnished with onion and eitherhorseradishor grated garlic, much as withsashimiofwhaleorhorse meat(basashi). When cooked, dolphin meat is cut into bite-size cubes and then batter-fried or simmered in amisosauce with vegetables. Cooked dolphin meat has a flavor very similar tobeef liver.[217]
Health concerns
There have been human health concerns associated with the consumption of dolphin meat in Japan after tests showed that dolphin meat contained high levels ofmercury.[218]There are no known cases ofmercury poisoningas 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.[219]
Similar concerns exist with the consumption of dolphin meat in theFaroe Islands,whereprenatalexposure tomethylmercuryandPCBsprimarily from the consumption of pilot whale meat has resulted inneuropsychologicaldeficits amongst children.[218]
TheFaroe Islandspopulation was exposed tomethylmercurylargely from contaminated pilot whale meat, which contained very high levels of about 2 mg methylmercury/kg. However, the Faroe Islands populations also eat significant numbers of fish. The study of about 900 Faroese children showed that prenatal exposure to methylmercury resulted in neuropsychological deficits at 7 years of age
See also
References
- ^Grady, John M.; Maitner, Brian S.; Winter, Ara S.; Kaschner, Kristin; Tittensor, Derek P.; Record, Sydne; Smith, Felisa A.; Wilson, Adam M.; Dell, Anthony I.; Zarnetske, Phoebe L.; Wearing, Helen J. (January 24, 2019)."Metabolic asymmetry and the global diversity of marine predators".Science.363(6425): eaat4220.doi:10.1126/science.aat4220.ISSN0036-8075.PMID30679341.S2CID59248474.
- ^abcLiddell, Henry George; Scott, Robert."δελφίς".A Greek-English Lexicon.Perseus Digital Library.
- ^Dolphin(Fourth ed.).Dictionary.com.RetrievedDecember 17,2006.
{{cite book}}:|work=ignored (help) - ^"delphinus, Charlton T. Lewis, Charles Short,A Latin Dictionary,on Perseus Digital Library ".
- ^"Killer Zionist dolphins? Hamas claims they exist".The Jerusalem Post.January 11, 2022.RetrievedMay 9,2024.
- ^Caracciolo, Frankie (June 19, 2017)."Biology Says It Sucks to Be This Rare Albino Dolphin".Inverse.RetrievedMay 9,2024.
- ^Aquatic Life of the World.Marshall Cavendish. November 1, 2000. p. 652.ISBN978-0-7614-7170-7.RetrievedJuly 23,2013.
- ^abWalker, Sally M. (November 2007).Dolphins.Lerner Publications. pp. 6, 30.ISBN978-0-8225-6767-7.
- ^"Coryphaena hippurus".FishBase.RetrievedJanuary 15,2016.
- ^Stephen Leatherwood (1988).Whales, Dolphins, and Porpoises of the Eastern North Pacific and Adjacent Arctic Waters: A Guide to Their Identification.Courier Dover Publications. p. 6.ISBN978-0-486-25651-1.RetrievedJuly 23,2013.
- ^Ron Hirschi (April 2002).Dolphins.Marshall Cavendish. p. 7.ISBN978-0-7614-1443-8.RetrievedJuly 23,2013.
- ^abStephanie Nowacek; Douglas Nowacek (2006).Discovering Dolphins.Voyageur Press. pp. 5, 9.ISBN978-0-7603-2561-2.RetrievedJuly 23,2013.
- ^Leatherwood, S.; Prematunga, W.P.; Girton, P.; McBrearty, D.; Ilangakoon, A.; McDonald, D (1991).Records of 'blackfish' (killer, false killer, pilot, pygmy killer, and melon-headed whales) in the Indian Ocean Sanctuary, 1772–1986 inCetaceans and cetacean research in the Indian Ocean Sanctuary.UNEP Marine Mammal Technical Report. pp. 33–65.ASINB00KX9I8Y8.
- ^"Style guide, animal names".Dictionary.com.Archived fromthe originalon November 14, 2007.RetrievedNovember 4,2007.
- ^"Dolphin Safari sightings log".2006. Archived fromthe originalon November 10, 2006.RetrievedDecember 17,2006.
- ^"Mammals of Texas – Rough-toothed Dolphin".Texas Tech University. 1997. Archived fromthe originalon September 15, 2008.RetrievedDecember 8,2006.
- ^Robin's Island."Dolphins at SeaWorld California".Archived fromthe originalon July 23, 2011.RetrievedDecember 17,2006.
- ^Denise L. Herzing; Kelly Moewe; Barbara J. Brunnick (2003)."Interspecies interactions between Atlantic spotted dolphins, Stenella frontalis and bottlenose dolphins, Tursiops truncatus, on Great Bahama Bank, Bahamas"(PDF).Archived fromthe original(PDF)on June 14, 2007.RetrievedDecember 17,2006.
- ^Lee, Jeanette J. (April 15, 2005)."Whale-Dolphin Hybrid Has Baby 'Wholphin'".Livescience.com. Associated Press. Archived fromthe originalon April 17, 2005.RetrievedMarch 2,2013.
- ^Northeastern Ohio Universities Colleges of Medicine and Pharmacy."Whales Descended From Tiny Deer-like Ancestors".ScienceDaily.RetrievedDecember 21,2007.
- ^Dawkins, Richard (September 6, 2016).The Ancestor's Tale: A Pilgrimage to the Dawn of Evolution.Houghton Mifflin Harcourt.ISBN978-0-547-52512-9.
- ^Thewissen,J. G. M.; Williams, E. M. (November 1, 2002). "THE EARLY RADIATIONS OF CETACEA (MAMMALIA): Evolutionary Pattern and Developmental Correlations".Annual Review of Ecology and Systematics.33(1): 73–90.doi:10.1146/annurev.ecolsys.33.020602.095426.
- ^"Introduction to Cetacea: Archaeocetes: The Oldest Whales".University of Berkeley.RetrievedJuly 25,2015.
- ^Thewissen, J. G. M.;Cooper, L. N.; Clementz, M. T.; Bajpai, S.; Tiwari, B. N. (2007)."Whales originated from aquatic artiodactyls in the Eocene epoch of India"(PDF).Nature.450(7173): 1190–1194.Bibcode:2007Natur.450.1190T.doi:10.1038/nature06343.PMID18097400.S2CID4416444.
- ^Fahlke, Julia M.; Gingerich, Philip D.; Welsh, Robert C.; Wood, Aaron R. (2011)."Cranial asymmetry in Eocene archaeocete whales and the evolution of directional hearing in water".PNAS.108(35): 14545–14548.Bibcode:2011PNAS..10814545F.doi:10.1073/pnas.1108927108.PMC3167538.PMID21873217.
- ^"More DNA Support for a Cetacea/Hippopotamidae Clade: The Blood-Clotting Protein Gene y-Fibrinogen".BBC News.May 8, 2002.RetrievedAugust 20,2006.
- ^"New Dawn".Walking with Prehistoric Beasts.2002. Discovery Channel.
- ^Rose, Kenneth D. (2001)."The Ancestry of Whales"(PDF).University of Washington. pp. 2216–2217.
- ^Bebej, R. M.; ul-Haq, M.; Zalmout, I. S.; Gingerich, P. D. (June 2012). "Morphology and Function of the Vertebral Column inRemingtonocetus domandaensis(Mammalia, cetacea) from the Middle Eocene Domanda Formation of Pakistan ".Journal of Mammalian Evolution.19(2): 77–104.doi:10.1007/S10914-011-9184-8.S2CID17810850.
- ^Lovett, Richard A. (November 8, 2006)."Dolphin With Four Fins May Prove Terrestrial Origins".National Geographic.Archived fromthe originalon November 13, 2006.RetrievedJuly 27,2012.
- ^Gatesy, John (February 3, 1997)."whales' closest relative"(PDF).University of Arizona. Archived fromthe original(PDF)on October 15, 2015.RetrievedAugust 29,2015.
- ^"The evolution of whales".University of Berkeley.RetrievedAugust 29,2015.
- ^Boisserie, Jean-Renaud; Lihoreau, Fabrice; Brunet, Michel (2005)."The position of Hippopotamidae within Cetartiodactyla".Proceedings of the National Academy of Sciences.102(5): 1537–1541.Bibcode:2005PNAS..102.1537B.doi:10.1073/pnas.0409518102.PMC547867.PMID15677331.
- ^Katherine Ralls; Sarah Mesnick.Sexual Dimorphism(PDF).pp. 1005–1011. Archived fromthe original(PDF)on July 25, 2019.RetrievedAugust 29,2015.
- ^abcdef"Cetacean Curriculum – A teacher's guide to introducing and using whales, dolphins, & porpoises in the classroom"(PDF).American Cetacean Society. November 28, 2004. Archived fromthe original(PDF)on August 7, 2012.RetrievedDecember 20,2013.
Sound production in cetaceans is a complex phenomenon not fully understood by scientists.
- ^Scholander, Per Fredrik (1940). "Experimental investigations on the respiratory function in diving mammals and birds".Hvalraadets Skrifter.22.
- ^abcKlinowska, Margaret; Cooke, Justin (1991).Dolphins, Porpoises, and Whales of the World: the IUCN Red Data Book(PDF).RetrievedAugust 29,2015.
- ^Stevens, C. Edward; Hume, Ian D. (1995).Comparative Physiology of the Vertebrate Digestive System.Cambridge University Press. p. 317.
- ^William F. Perrin; Bernd Wursig; J. G.M.Thewissen(February 26, 2009).Encyclopedia of Marine Mammals.Academic Press.ISBN978-0-08-091993-5.RetrievedJune 28,2013.
- ^Carol J. Howard (December 1, 1995).Dolphin Chronicles.Random House Digital, Inc. pp. 129–.ISBN978-0-553-37778-1.RetrievedNovember 26,2012.
- ^Bernd G. Würsig; Bernd Wursig, Melany Wursig (2010).The Dusky Dolphin: Master Acrobat Off Different Shores.Academic Press. pp. 156–.ISBN978-0-12-373723-6.RetrievedNovember 26,2012.
- ^Edward F. Gibbons Jr.; Barbara Susan Durrant; Jack Demarest (1995).Conservation Endangered Spe: An Interdisciplinary Approach.SUNY Press. pp. 435–.ISBN978-0-7914-1911-3.RetrievedNovember 26,2012.
- ^abcdefgCozzi, Bruno; Huggenberger, Stefan; Oelschläger, Helmut (2017).Anatomy of Dolphins: Insights into Body Structure and Function.Elsevier Inc. p. 23.ISBN978-0124072299.
- ^Paxton, Steve; Peckham, Michelle; Knibbs, Adele (2003)."The Leeds Histology Guide".
- ^"All About Bottlenose Dolphins – Adaptations".seaworld.org.RetrievedDecember 6,2020.
- ^Kremers, Dorothee; Célérier, Aurélie; Schaal, Benoist; et al. (May 11, 2016)."Sensory Perception in Cetaceans: Part I—Current Knowledge about Dolphin Senses As a Representative Species".Frontiers in Ecology and Evolution.4.doi:10.3389/fevo.2016.00049.ISSN2296-701X.
- ^"How Does Blubber Keep Animals Warm?".animals.mom.com.RetrievedDecember 6,2020.
- ^ab"How does blubber keep whales warm?".Whale & Dolphin Conservation USA.October 27, 2012.RetrievedDecember 6,2020.
- ^Tanaka, Hiroto; Li, Gen; Uchida, Yusuke; Nakamura, Masashi; Ikeda, Teruaki; Liu, Hao (2019)."Measurement of time-varying kinematics of a dolphin in burst accelerating swimming".PLOS ONE.14(1): e0210860.Bibcode:2019PLoSO..1410860T.doi:10.1371/journal.pone.0210860.ISSN1932-6203.PMC6353170.PMID30699184.
- ^"Beluga Whale: The White Melon-headed Creature Of The Cold".Yellowmagpie.com. June 27, 2012.RetrievedAugust 12,2013.
- ^"About Whales".Whalesalive.org.au. June 26, 2009. Archived fromthe originalon August 12, 2013.RetrievedAugust 12,2013.
- ^"Boto (Amazon river dolphin)Inia geoffrensis".American Cetacean Society.2002.RetrievedSeptember 12,2015.
- ^"Dolphins conserve oxygen and prevent dive-related problems by consciously decreasing their heart rates before diving".phys.org.RetrievedDecember 8,2020.
- ^Fahlman, Andreas; Cozzi, Bruno; Manley, Mercy; Jabas, Sandra; Malik, Marek; Blawas, Ashley; Janik, Vincent M. (2020)."Conditioned Variation in Heart Rate During Static Breath-Holds in the Bottlenose Dolphin (Tursiops truncatus)".Frontiers in Physiology.11:604018.doi:10.3389/fphys.2020.604018.ISSN1664-042X.PMC7732665.PMID33329056.S2CID227128277.
Available underCC BY 4.0.
- ^Norena, S. R.; Williams, T. M. (2000). "Body size and skeletal muscle myoglobin of cetaceans: adaptations for maximizing dive duration".Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology.126(2): 181–191.doi:10.1016/s1095-6433(00)00182-3.PMID10936758.
- ^Nummela, Sirpa;Thewissen, J.G.M;Bajpai, Sunil; Hussain, Taseer; Kumar, Kishor (2007)."Sound transmission in archaic and modern whales: Anatomical adaptations for underwater hearing"(PDF).The Anatomical Record.290(6): 716–733.doi:10.1002/ar.20528.PMID17516434.S2CID12140889.
- ^Cranford, Ted W.; Amundin, Mats; Norris, Kenneth S. (1996). "Functional morphology and homology in the odontocete nasal complex: Implications for sound generation".Journal of Morphology.228(3): 223–285.doi:10.1002/(SICI)1097-4687(199606)228:3<223::AID-JMOR1>3.0.CO;2-3.ISSN0362-2525.PMID8622183.
- ^abcdThomas, Jeanette A.; Kastelein, Ronald A., eds. (2002).Sensory Abilities of Cetaceans: Laboratory and Field Evidence.Vol. 196.doi:10.1007/978-4899-0858-2(inactive January 31, 2024).ISBN978-1-4899-0860-5.
{{cite book}}:CS1 maint: DOI inactive as of January 2024 (link) - ^Perrin, William F.; Wursig, Bernd;Thewissen,J.G.M. 'Hans', eds. (February 26, 2009).Encyclopedia of Marine Mammals.Academic Press.ISBN978-0-08-091993-5.
- ^Ketten, Darlene R. (1992)."The Marine Mammal Ear: Specializations for Aquatic Audition and Echolocation".In Webster, Douglas B.; Fay, Richard R.; Popper, Arthur N. (eds.).The Evolutionary Biology of Hearing.Springer. pp. 725–727.RetrievedMarch 1,2013.
- ^Jeanette A. Thomas; Ronald A. Kastelein., eds. (1990).A Proposed Echolocation Receptor for the Bottlenose Dolphin (Tursiops truncatus): Modelling the Receive Directivity from Tooth and Lower Jaw GeometryNATO ASI Series A: Sensory Abilities of Cetaceans.Vol. 196. NY: Plenum. pp. 255–267.ISBN978-0-306-43695-6.
- ^Bjorn Mauck; Ulf Eysel; Guide Dehnhardt (2000)."Selective heating of vibrissal follicles in seals (Phoca vitulina) and dolphins (Sotalia fluviatilis guianensis) "(PDF).Journal of Experimental Biology.203(14): 2125–2131.doi:10.1242/jeb.203.14.2125.PMID10862725.RetrievedMarch 11,2007.
- ^Harley, Heidi E.; DeLong, Caroline M. (2008)."Echoic Object Recognition by the Bottlenose Dolphin".Comparative Cognition & Behavior Reviews.3:45–65.doi:10.3819/ccbr.2008.30003.
- ^Stepanek, Laurie (May 19, 1998)."Amazon River Dolphin (Inia geoffrensis) ".Texas Marine Mammal Stranding Network. Archived fromthe originalon February 6, 2007.RetrievedNovember 20,2013.
- ^Mass, Alla M.; Supin, Alexander Y. A. (May 21, 2007)."Adaptive features of aquatic mammals' eyes".Anatomical Record.290(6): 701–715.doi:10.1002/ar.20529.PMID17516421.S2CID39925190.
- ^Siebert, Charles (July 8, 2009)."Watching Whales Watching Us".The New York Times Magazine.RetrievedAugust 29,2015.
- ^Watson, K.K.; Jones, T. K.; Allman, J. M. (2006). "Dendritic architecture of the Von Economo neurons".Neuroscience.141(3): 1107–1112.doi:10.1016/j.neuroscience.2006.04.084.PMID16797136.S2CID7745280.
- ^Allman, John M.; Watson, Karli K.; Tetreault, Nicole A.; Hakeem, Atiya Y. (2005). "Intuition and autism: a possible role for Von Economo neurons".Trends Cogn Sci.9(8): 367–373.doi:10.1016/j.tics.2005.06.008.PMID16002323.S2CID14850316.
- ^Hof, Patrick R.; Van Der Gucht, Estel (2007)."Structure of the cerebral cortex of the humpback whale,Megaptera novaeangliae(Cetacea, Mysticeti, Balaenopteridae) ".The Anatomical Record.290(1): 1–31.doi:10.1002/ar.20407.PMID17441195.S2CID15460266.
- ^Moore, Jim."Allometry".University of California San Diego.RetrievedAugust 9,2015.
- ^"How smart are they?".Orlando Sentinel.March 7, 2010.
- ^Fields, R. Douglas."Are whales smarter than we are?".Scientific American.RetrievedAugust 9,2015.
- ^"Elephant Self-Awareness Mirrors Humans".Live Science. October 30, 2006.RetrievedAugust 29,2015.
- ^abcDerr, Mark (May 2001)."Mirror test".The New York Times.RetrievedAugust 3,2015.
- ^Marten, Ken; Psarakos, Suchi (June 1995). "Using Self-View Television to Distinguish between Self-Examination and Social Behavior in the Bottlenose Dolphin (Tursiops truncatus)".Consciousness and Cognition.4(2): 205–224.doi:10.1006/ccog.1995.1026.PMID8521259.S2CID44372881.
- ^Gallup Jr, Gordon G., and James R. Anderson. "Self-recognition in animals: Where do we stand 50 years later? Lessons from cleaner wrasse and other species." Psychology of Consciousness: Theory, Research, and Practice (2019).
- ^Davidson College, biology department (2001)."Bottlenose Dolphins – Altruism".Archived fromthe originalon January 6, 2010.RetrievedMarch 12,2008.
- ^Lilley, Ray (March 12, 2008)."Dolphin Saves Stuck Whales, Guides Them Back to Sea".National Geographic.Associated Press. Archived fromthe originalon March 13, 2008.RetrievedJuly 8,2012.
- ^"Dolphins save swimmers from shark".CBC News. November 24, 2004.RetrievedMarch 11,2007.
- ^Celizic, Mike (November 8, 2007)."Dolphins save surfer from becoming shark's bait".Today. Archived fromthe originalon November 10, 2007.RetrievedMarch 2,2022.
- ^Dolphin Mysteries: Unlocking the Secrets of Communication.Yale University Press. 2008. p. 83.ISBN978-0-300-12112-4.RetrievedMarch 16,2014.
- ^Rowan Hooper (2005)."Dolphins teach their children to use sponges".RetrievedJune 28,2021.
- ^Nic Fleming (December 5, 2007)."Dolphins woo females with bunches of weeds".The Daily Telegraph.London. Archived fromthe originalon December 8, 2007.RetrievedMarch 2,2022.
- ^Bathgate, Adrian (March 13, 2008)."Dolphin saves 2 whales stuck on New Zealand beach".Reuters.RetrievedMarch 2,2022.
- ^"Dolphins try to save dying companion".BBC. January 28, 2013.RetrievedDecember 30,2016.
- ^"Dolphin spotters shaken by Ceredigion porpoise killing".BBC News.August 24, 2023.RetrievedAugust 24,2023.
- ^George Johnson."Is Flipper A Senseless Killer?".Archived fromthe originalon November 11, 2006.RetrievedDecember 17,2006.
- ^Dolphin pictured killing porpoise by flipping it into air,BBC
- ^abcSilva, J. Jr.; Silva, F.; Sazima, I. (2005)."Rest, nurture, sex, release, and play: diurnal underwater behaviour of the spinner dolphin at Fernando de Noronha Archipelago, SW Atlantic – Mating behaviour"(PDF).Archived fromthe original(PDF)on March 16, 2014.RetrievedMarch 16,2014.
- ^CMSSotalia fluviatilis – ReproductionArchivedMay 20, 2013, at theWayback Machine,article. Retrieved March 16, 2013.
- ^Orcas (Killer Whales), Orcinus orca – Life History,Marinebio.org. Retrieved March 16, 2014.
- ^Simmonds, Mark (2007).Whales and Dolphins of the World.New Holland Publishers. p. 32.ISBN978-1-84537-820-2.[permanent dead link]
- ^W. Perrin; S. Reilly (1984).Reproductive Parameters of Dolphins(PDF).
- ^Volker Sommer; Paul L. Vasey (2006)."Chapter 4".Homosexual Behaviour in Animals – an Evolutionary perspective.
- ^Bruce Bagemihl (1999).Biological Exuberance – Animal Homosexuality and Natural Diversity.
- ^Moye, David (September 7, 2012)."SCARY VIDEO: Dolphin Gets Too Frisky With Scuba Divers".HuffPost.RetrievedDecember 30,2016.
- ^Amy Samuels; Lars Bejder;Rochelle Constantine;Sonja Heinrich (2003)."chapter 15 Marine Mammals: Fisheries, Tourism and Management Issues"(PDF).Cetaceans that are typically lonely and seek human company.pp. 266–268.RetrievedDecember 17,2006.
- ^Scott, Erin; Mann, Janet; Watson-Capps, Jana; Sargeant, Brooke; Connor, Richard (2005). "Aggression in bottlenose dolphins: Evidence for sexual coercion, male-male competition, and female tolerance through analysis of tooth-rake marks and behaviour".Behaviour.142(1): 21–44.doi:10.1163/1568539053627712.S2CID4502911.
- ^R. Connor; R. Smolker; A. Richards (1992).Two levels of alliance formation among male bottlenose dolphins(PDF).
- ^ Mukhametov, L. M.; Supin, A. Ya. (1978). "Sleep and vigil in dolphins".Marine mammals.Moscow:Nauka.
- ^Mukhametov, Lev (1984). "Sleep in Marine Mammals".Sleep Mechanisms.Experimental Brain Research Supplementum. Vol. 8 (suppl.). pp. 227–238.doi:10.1007/978-3-642-69554-4_17(inactive January 31, 2024).ISBN978-3-642-69556-8.
{{cite book}}:|journal=ignored (help)CS1 maint: DOI inactive as of January 2024 (link) - ^Dallas Grasby (1994)."Excerpts from 'Sleep in marine mammals', L.M. Mukhametov".Experimental Brain Research.8 (suppl.).RetrievedFebruary 11,2008.
- ^McCormick, James G. (2007)."Behavioral Observations of Sleep and Anesthesia in the Dolphin: Implications for Bispectral Index Monitoring of Unihemispheric Effects in Dolphins".Anesthesia & Analgesia.104(1): 239–241.doi:10.1213/01.ane.0000250369.33700.eb.PMID17179314.S2CID40939919.
- ^"Sperm whales caught 'cat napping'".BBC News.February 20, 2008.RetrievedApril 9,2008.
- ^Martin, G. Neil; Carlson, Neil R.; Buskist, William (1997).Psychology, third edition.Pearson Allyn & Bacon. p. 383.ISBN978-0-273-71086-8.
- ^abcd"Dolphin's diet".Archived fromthe originalon September 27, 2013.
- ^U.S. Department of Commerce National Oceanic and Atmospheric Administration National Marine Fisheries Service."Coastal Stock(s) of Atlantic Bottlenose Dolphin: Status Review and Management Proceedings and Recommendations from a Workshop held in Beaufort, North Carolina, 13 September 1993 – 14 September 1993"(PDF).pp. 56–57.
- ^Gregory K. Silber, Dagmar Fertl (1995) –Intentional beaching by bottlenose dolphins (Tursiops truncatus) in the Colorado River Delta, Mexico.
- ^M.B. Santos; R. Fernández; A. López; J.A. Martínez; G.J. Pierce (2007). "Variability in the diet of bottlenose dolphin,Tursiops truncatus,in Galician waters, north-western Spain, 1990–2005 ".Journal of the Marine Biological Association of the UK.87(1): 231.Bibcode:2007JMBUK..87..231S.doi:10.1017/S0025315407055233.S2CID85767272.
- ^"Brazil's sexiest secret".The Daily Telegraph.London. March 8, 2006. Archived fromthe originalon March 13, 2008.RetrievedMarch 11,2007.
- ^Moti Nissani (2007)."Bottlenose Dolphins in Laguna Requesting a Throw Net Supporting material for Dr. Nissani's presentation at the 2007 International Ethological Conference".YouTube.Archivedfrom the original on December 11, 2021.RetrievedFebruary 13,2008.
- ^Hunt, Katie (June 25, 2020)."Dolphins are learning smart fish-catching trick from peers, not mothers".CNN.RetrievedJune 25,2020.
- ^Viegas, Jennifer (2011)."Dolphins Talk Like Humans".Discovery News.Archived fromthe originalon September 24, 2011.RetrievedSeptember 19,2011.
- ^Au, Whitlow W.L. (December 6, 2012).The Sonar of Dolphins.Springer Science & Business Media.ISBN978-1-4612-4356-4.
- ^"Dolphins 'call each other by name'".BBC News.July 22, 2013.
- ^Janik, Vincent; Laela Sayigh (May 7, 2013). "Communication in bottlenose dolphins: 50 years of signature whistle research".Journal of Comparative Physiology.199(6): 479–489.doi:10.1007/s00359-013-0817-7.PMID23649908.S2CID15378374.
- ^"Marine Mammal vocalizations: language or behavior?".August 24, 2013.
- ^"Dolphins keep lifelong social memories, longest in a non-human species".August 24, 2013.
- ^Emily T. Griffiths (2009). "Whistle repertoire analysis of the short beaked Common Dolphin,Delphinus delphis,from the Celtic Deep and the Eastern Tropical Pacific Ocean",Master's Thesis, School of Ocean Sciences Bangor University
- ^Melba C. Caldwell et al. –Statistical Evidence for Signature Whistles in the Spotted Dolphin,Stenella plagiodon.
- ^Melba C. Caldwell et al. –Statistical Evidence for Signature Whistles in the Pacific Whitesided Dolphin,Lagenorhynchus obliquidens.
- ^Rüdiger Riesch et al. –Stability and group specificity of stereotyped whistles in resident killer whales, Orcinus orca, off British Columbia.
- ^Quick, Nicola; Vincent Janik (2008). "Whistle Rates of Wild Bottlenose Dolphins (Tursiops truncatus): Influences of Group Size and Behavior ".Journal of Comparative Psychology.122(3): 305–311.doi:10.1037/0735-7036.122.3.305.PMID18729659.
- ^abWeihs, D. (2002)."Dynamics of Dolphin Porpoising Revisited".Integrative and Comparative Biology.42(5): 1071–1078.doi:10.1093/icb/42.5.1071.PMID21680390.
- ^David Lusseau (2006),Why do dolphins jump? Interpreting the behavioural repertoire of bottlenose dolphins (Tursiops sp.) in Doubtful Sound, New Zealand
- ^Corey Binns – LiveScience (2006),How Dolphins Spin, and Why,article. Retrieved September 8, 2013.
- ^abcRobin D. Paulos (2010),Play in Wild and Captive Cetaceans
- ^Brenda McCowan; Lori Marino; Erik Vance; Leah Walke; Diana Reiss (2000)."Bubble Ring Play of Bottlenose Dolphins (Tursiops truncatus): Implications for Cognition "(PDF).Journal of Comparative Psychology.l14(1): 98–106.doi:10.1037/0735-7036.114.1.98.PMID10739315.Archived fromthe original(PDF)on June 10, 2010.RetrievedAugust 2,2010.
- ^Mark H. Deakos et al. (2010),Two Unusual Interactions Between a Bottlenose Dolphin (Tursiops truncatus) and a Humpback Whale (Megaptera novaeangliae) in Hawaiian Waters.
- ^Cathy Hayes for Irish Central (2011),Amazing footage of a dog playing with a dolphin off the coast of Ireland,article. Retrieved September 8, 2013.
- ^Staff writers (February 8, 2017)."'Puff, puff, pass': How WA's dolphins are using blowfish to get high ".WAToday.No. February 8, 2017.RetrievedJune 9,2017.
- ^Moylan, Brian (February 10, 2017)."Apparently Dolphins in Australia Like to Get Stoned by Chewing on Toxic Blowfish".Vice.RetrievedApril 6,2017.
- ^Wilcox, Christie (December 30, 2013)."Do Stoned Dolphins Give 'Puff Puff Pass' A Whole New Meaning?".Science Sushi.Discover. Archived fromthe originalon November 14, 2019.RetrievedJune 9,2017.
- ^abc"Billie".Dolphin Dock.February 15, 2018.RetrievedApril 4,2022.
- ^abcBossley M, Steiner A, Brakes P, Shrimpton J, Foster C, Rendell L (September 2018)."Tail walking in a bottlenose dolphin community: the rise and fall of an arbitrary cultural 'fad'".Biol. Lett.14(9).doi:10.1098/rsbl.2018.0314.PMC6170752.PMID30185606.
- ^abPisani, Ashleigh (May 9, 2018)."The incredible tale of Billie the Port River dolphin — the world's first wild tailwalker".Adelaide Now.Portside Messenger.
- ^abSutton, Malcolm (April 4, 2022)."Why are the dolphins dying?".ABC News.Australian Broadcasting Corporation.RetrievedApril 4,2022.
- ^ab"The amazing story of Billie, the dolphin who taught her peers how to moonwalk".Gentside UK.October 15, 2018.RetrievedApril 4,2022.
- ^Michael R. Heithaus (1999),Predator-prey and competitive interactions between sharks (order Selachii) and dolphins (parvorder Odontoceti): a review
- ^Nadia Drakefor WIRED (2013),Photographer Captures Stunning Killer Whale Attack on Dolphin,article. Retrieved March 14, 2022.
- ^Bossart, G. D. (2007)."Emerging diseases in marine mammals: from dolphins to manatees"(PDF).Microbe.2(11): 544–549. Archived fromthe original(PDF)on January 14, 2014.
- ^Woodard, J. C.; Zam, S. G.; Caldwell, D. K.; Caldwell, M. C. (1969)."Some Parasitic Diseases of Dolphins".Veterinary Pathology.6(3): 257–272.doi:10.1177/030098586900600307.PMID5817449.S2CID26842976.
- ^Bellière, E. N.; Esperón, F.; Sánchez-Vizcaíno, J. M. (2011). "Genetic comparison among dolphin morbillivirus in the 1990–1992 and 2006–2008 Mediterranean outbreaks".Infection, Genetics and Evolution.11(8): 1913–1920.Bibcode:2011InfGE..11.1913B.doi:10.1016/j.meegid.2011.08.018.PMID21888991.
- ^Jane J. Lee forNational Geographic(2013),What's Killing Bottlenose Dolphins? Experts Discover Cause.,article. Retrieved December 4, 2013.
- ^Guardo, G. D.; Marruchella, G.; Agrimi, U.; Kennedy, S. (2005). "Morbillivirus Infections in Aquatic Mammals: A Brief Overview".Journal of Veterinary Medicine, Series A.52(2): 88–93.doi:10.1111/j.1439-0442.2005.00693.x.hdl:11575/80640.PMID15737178.
- ^Stone, B. M.; Blyde, D. J.; Saliki, J. T.; Blas-Machado, U.; Bingham, J.; Hyatt, A.; Wang, J.; Payne, J.; Crameri, S. (2011)."Fatal cetacean morbillivirus infection in an Australian offshore bottlenose dolphin (Tursiops truncatus)".Australian Veterinary Journal.89(11): 452–457.doi:10.1111/j.1751-0813.2011.00849.x.PMID22008125.
- ^US National Marine Mammal Foundation (February 18, 2010)."Scientists Find Clues in Dolphins to Treat Diabetes in Humans".Archived fromthe originalon April 11, 2010.RetrievedFebruary 20,2010.
- ^Georgetown University Medical Center."Dolphins'" Remarkable "Recovery from Injury Offers Important Insights for Human Healing".Archived fromthe originalon December 5, 2011.RetrievedJuly 26,2011.
- ^Viegas, Jen (August 14, 2014)."Shark vs. Dolphin Battles Can Have Surprising Outcomes".Seeker – Science. World. Exploration. Seek for yourself.RetrievedNovember 27,2016.
- ^"Can Dolphins Kill Sharks?".animalquestions.org.December 2, 2011.
- ^"Do dolphins really beat up sharks?".ReefQuest Centre for Shark Research.
- ^Douglas Williams for Shanghai Daily (December 4, 2006)."Yangtze dolphin may be extinct".Archived fromthe originalon January 14, 2018.RetrievedJanuary 13,2018.
- ^Palumbi, Stephen R.(June 30, 2010)."TED: Stephen Palumbi: Following the mercury trail".Archivedfrom the original on December 11, 2021.RetrievedJuly 25,2011– via YouTube.
- ^Clover, Charles (2008).The End of the Line: How Overfishing is Changing the World and what We Eat.University of California Press.ISBN978-0-520-25505-0.
- ^Díaz López, Bruno; Bernal Shirai, J.A. (2006). "Bottlenose dolphin (Tursiops truncatus) presence and incidental capture in a marine fish farm on the north-eastern coast of Sardinia (Italy) ".Journal of the Marine Biological Association of the UK.87:113–117.doi:10.1017/S0025315407054215.S2CID86115152.
- ^Díaz López, Bruno (2006)."Interactions between Mediterranean bottlenose dolphins (Tursiops truncatus) and gillnets off Sardinia, Italy ".ICES Journal of Marine Science.63(5): 946–951.Bibcode:2006ICJMS..63..946D.doi:10.1016/j.icesjms.2005.06.012.
- ^ab Matsutani, Minoru (September 23, 2009)."Details on how Japan's dolphin catches work".Japan Times.p. 3. Archived fromthe originalon September 27, 2009.
- ^ Johnston, Eric (September 23, 2009)."Mercury danger in dolphin meat".Japan Times.p. 3.
- ^"Aussie shark population in staggering decline. Rhian Deutrom. December 14, 2018. Retrieved December 26, 2018".
- ^ab"Action for Dolphins. Queensland's Shark Control Program Has Snagged 84,000 Animals. Thom Mitchell. November 20, 2015. Retrieved December 26, 2018".May 12, 2023.
- ^""Shark Culling". marineconservation.org.au. Archived from the original on 2018-10-02. Retrieved December 26, 2018 ".Archived fromthe originalon October 2, 2018.
- ^"Separating fact from fiction in QLD's shark culling program.Nicola Beynon. October 19, 2018. Retrieved December 26, 2018 ".October 19, 2018.
- ^""Shark Nets". sharkangels.org. Retrieved December 26, 2018 ".
- ^"Time of Truth For US Dolphin Safe Logos".atuna.Archived fromthe originalon October 15, 2015.RetrievedAugust 29,2015.
- ^CBC news (October 9, 2003)."Navy sonar may be killing whales, dolphins".CBC News.RetrievedOctober 27,2008.
- ^"Npower renewables Underwater noise & vibration, section 9.4"(PDF).Archived fromthe original(PDF)on July 22, 2007.RetrievedOctober 27,2008.
- ^abcdEvans, Peter G.H.; Bjørge, Arne (November 28, 2013)."Impacts of climate change on marine mammals"(PDF).MCCIP Science Review 2013.
- ^abcdefWürsig, Bernd; Reeves, Randall R.; Ortega-Ortiz, J. G. (2001), Evans, Peter G. H.; Raga, Juan Antonio (eds.),"Global Climate Change and Marine Mammals",Marine Mammals: Biology and Conservation,Boston, MA: Springer US, pp. 589–608,doi:10.1007/978-1-4615-0529-7_17,ISBN978-1-4615-0529-7,retrievedMay 1,2021
- ^Salvadeo, CJ; Lluch-Belda, D; Gómez-Gallardo, A; Urbán-Ramírez, J; MacLeod, CD (March 10, 2010)."Climate change and a poleward shift in the distribution of the Pacific white-sided dolphin in the northeastern Pacific".Endangered Species Research.11(1): 13–19.doi:10.3354/esr00252.ISSN1863-5407.
- ^Salvadeo, CJ; Lluch-Belda, D; Gómez-Gallardo, A; Urbán-Ramírez, J; MacLeod, CD (March 10, 2010)."Climate change and a poleward shift in the distribution of the Pacific white-sided dolphin in the northeastern Pacific".Endangered Species Research.11(1): 13–19.doi:10.3354/esr00252.ISSN1863-5407.
- ^Cañadas, A.; Vázquez, J.A. (July 1, 2017)."Common dolphins in the Alboran Sea: Facing a reduction in their suitable habitat due to an increase in Sea surface temperature".Deep Sea Research Part II: Topical Studies in Oceanography.141:306–318.Bibcode:2017DSRII.141..306C.doi:10.1016/j.dsr2.2017.03.006.ISSN0967-0645.
- ^MacLeod, Colin D.; Bannon, Sarah M.; Pierce, Graham J.; Schweder, Caroline; Learmonth, Jennifer A.; Herman, Jerry S.; Reid, Robert J. (August 1, 2005)."Climate change and the cetacean community of north-west Scotland".Biological Conservation.124(4): 477–483.Bibcode:2005BCons.124..477M.doi:10.1016/j.biocon.2005.02.004.ISSN0006-3207.
- ^abcGomez-Salazar, Catalina; Coll, Marta; Whitehead, Hal (December 1, 2012)."River dolphins as indicators of ecosystem degradation in large tropical rivers".Ecological Indicators.23:19–26.Bibcode:2012EcInd..23...19G.doi:10.1016/j.ecolind.2012.02.034.ISSN1470-160X.
- ^Wild, Sonja; Krützen, Michael; Rankin, Robert W.; Hoppitt, William J.E.; Gerber, Livia; Allen, Simon J. (April 1, 2019)."Long-term decline in survival and reproduction of dolphins following a marine heatwave".Current Biology.29(7): R239–R240.Bibcode:2019CBio...29.R239W.doi:10.1016/j.cub.2019.02.047.hdl:1983/1a397eb9-1713-49b5-a2fb-f0d7c747e724.ISSN0960-9822.PMID30939303.
- ^"Taras".Archived fromthe originalon February 8, 2007.RetrievedOctober 3,2010.
- ^Eyers, Jonathan (December 3, 2012).Don't Shoot the Albatross!: Nautical Myths and Superstitions.Bloomsbury Publishing.ISBN978-1-4081-3213-5.
- ^HerodotusI.23;ThucydidesI.128, 133;Pausaniasiii.25, 4
- ^Singh, Vijay (1997).The River Goddess.Creative Education.ISBN978-0-88682-825-7.
- ^Cressey, Jason (September 1998)."Making a Splash in the Pacific: Dolphin and Whale Myths and Legends of Oceania"(PDF).islandheritage.org.The POD-People, Oceans, Dolphins (Vancouver, Canada). Archived fromthe original(PDF)on November 20, 2018.RetrievedOctober 19,2018.
- ^Hentea, Călin (2007).Brief Romanian Military History.Scarecrow Press.ISBN978-0-8108-5820-6.
- ^Ali, Arif (1996).Barbados: Just Beyond Your Imagination.Hertford, UK: Hansib Publications. p. 16.ISBN978-1-870518-54-3.
- ^Ali, Arif (1996).Barbados: Just Beyond Your Imagination.Hansib. p. 16.ISBN978-1-870518-54-3.
- ^Description of the coat of arms,Borough of Poole information sheet, undated
- ^Atlantis: The Palm, Dubai."Swim With the Dolphins in Dubai".atlantisthepalm.com.RetrievedMarch 11,2016.
- ^Dubai Dolphinarium."The Dubai Dolphinarium".dubaidolphinarium.ae.RetrievedMarch 11,2016.
- ^Rose, Naoimi; Parsons, E.C.M.; Farinato, Richard.The Case Against Marine Mammals in Captivity(PDF)(4 ed.). Humane Society of the United States. pp. 13, 42, 43, 59. Archived fromthe original(PDF)on September 30, 2018.RetrievedJanuary 7,2016.
- ^Sean B. Carroll."Remarkable creatures".RetrievedJanuary 6,2016.
- ^"Orcas in Captivity – A look at killer whales in aquariums and parks".November 23, 2009.RetrievedSeptember 6,2015.
- ^india.gov."National Aquatic Animal".india.gov.
- ^Rose, N. A. (2011)."Killer Controversy: Why Orcas Should No Longer Be Kept in Captivity"(PDF).Humane Society International and the Humane Society of the United States.RetrievedDecember 21,2014.
- ^"Whale Attack Renews Captive Animal Debate".CBS News.March 1, 2010.RetrievedSeptember 6,2015.
- ^Armstrong, Susan J.; Botzler, Richard G. (November 18, 2016).The Animal Ethics Reader.Taylor & Francis.ISBN978-1-317-42196-2.
- ^abWilliam Broad (July 6, 1999)."An article on the aggressive nature of dolphins".Fishingnj.org.RetrievedJuly 25,2011.
- ^Zimmerman, Tim (2011). "The Killer in the Pool".The Best American Sampler 2011.Houghton Mifflin Harcourt. p. 336.
- ^"Corpse Is Found on Whale".The New York Times.July 7, 1999.RetrievedSeptember 11,2011.
- ^"SeaWorld trainer killed by killer whale".CNN. February 25, 2010.RetrievedMarch 11,2010.
- ^Howard, Brian (January 6, 2017)."Why Tilikum, SeaWorld's Killer Orca, Was Infamous".National Geographic.Archived fromthe originalon August 2, 2019.RetrievedSeptember 20,2019.
- ^Pilkington, Ed (February 25, 2010)."Killer whale Tilikum to be spared after drowning trainer by ponytail".The Guardian.London.
- ^"Killer whale bumps but doesn't bite boy".Juneau Empire – Alaska's Capital City Online Newspaper. August 19, 2005. Archived fromthe originalon April 11, 2010.RetrievedJuly 25,2011.
- ^Wong, David (February 7, 2008)."The 6 Cutest Animals That Can Still Destroy You".Cracked.com.RetrievedJuly 25,2011.
- ^"Male Dolphin Kills Man".Science-frontiers.com. September–October 1995.RetrievedJuly 25,2011.
- ^"LONE DOLPHINS – FRIEND OR FOE?".BBC. September 9, 2002.RetrievedFebruary 5,2012.
- ^White, Thomas I. (May 18, 2009).In Defense of Dolphins: The New Moral Frontier.John Wiley & Sons.ISBN978-0-470-46969-9.
- ^Leake, Jonathan; Brooks, Helen (January 3, 2010)."Scientists say dolphins should be treated as 'non- human persons'"(PDF).The Sunday Times.Archived fromthe original(PDF)on April 10, 2016.RetrievedJanuary 4,2010– via dolphinmovie.com.
- ^Land, Graham (July 29, 2013).Dolphin rights: The world should follow India's leadArchivedAugust 29, 2013, at theWayback Machine.Asiancorrespondent.com.Hybrid News Ltd. Retrieved July 29, 2013.
- ^"Policy on establishment of dolphinarium"(PDF).Archived fromthe original(PDF)on March 22, 2016.RetrievedAugust 10,2013.
- ^"Dolphins gain unprecedented protection in India | DW | 24.05.2013".DW.COM.
- ^PBS – Frontline."The Story of Navy dolphins".PBS.RetrievedJune 8,2008.
- ^"Iran buys kamikaze dolphins".BBC News.March 8, 2000.RetrievedJune 7,2008.
- ^Hsu, Jeremy (December 10, 2020)."The Military Wants to Hide Covert Messages in Marine Mammal Sounds".Hakai Magazine.RetrievedDecember 14,2020.
- ^Antonioli, C; Reveley, MA (2005)."Randomised controlled trial of animal facilitated therapy with dolphins in the treatment of depression".BMJ (Clinical Research Ed.).331(7527): 1231–1234.doi:10.1136/bmj.331.7527.1231.JSTOR25455488.PMC1289317.PMID16308382.
- ^Biju Basil; Maju Mathews (2005)."Methodological concerns about animal-facilitated therapy with dolphins".BMJ.331(7529): 1407.doi:10.1136/bmj.331.7529.1407.PMC1309662.PMID16339258.
- ^Lori Marino; Scott O. Lilienfeld (2007)."Dolphin-Assisted Therapy: more flawed data and more flawed conclusions"(PDF).Anthrozoös.20(3): 239–49.CiteSeerX10.1.1.554.7777.doi:10.2752/089279307X224782.S2CID6119940.Archived fromthe original(PDF)on February 28, 2008.RetrievedFebruary 20,2008.
- ^McCurry, Justin (September 14, 2009)."Dolphin slaughter turns sea red as Japan hunting season returns".The Guardian.London.RetrievedMay 24,2010.
- ^Hall, Kevin G. (2003). "Dolphin meat widely available in Peruvian stores: Despite protected status, 'sea pork' is popular fare".The Seattle Times.
- ^Kearney, Christine (July 31, 2009)."Dolphin slaughter in Japan subject of new film".Reuters.RetrievedDecember 23,2023.
- ^イルカの vị tạch căn thái chử[Dolphin in Miso Vegetable Stew].Cookpad(in Japanese). 2010.RetrievedMay 16,2011.
- ^abcWorld Health Organization/United Nations Environment ProgrammeDTIE Chemicals Branch (2008)."Guidance for identifying populations at risk from mercury exposure"(PDF).p. 36.RetrievedAugust 29,2013.
- ^"Bình thành １５ niên ６ nguyệt ３ nhật に công biểu した “Thủy ngân を hàm hữu する ngư giới loại đẳng の nhiếp thực に quan する chú ý sự hạng” について ".Ministry of Health, Labour and Welfare(in Japanese).
Further reading
- Carwardine, M.,Whales, Dolphins and Porpoises,Dorling Kindersley, 2000.ISBN978-0-7513-2781-6.
- Williams, Heathcote,Whale Nation,New York, Harmony Books, 1988.ISBN978-0-517-56932-0.
External links
Definitionsfrom Wiktionary
Mediafrom Commons
Taxafrom Wikispecies
Datafrom Wikidata
Conservation, research and news:
- De Rohan, Anuschka."Why dolphins are deep thinkers",The Guardian,July 3, 2003.
- The Dolphin Institute
- The Oceania Project, Caring for Whales and Dolphins
- Tursiops.org: Current Cetacean-related news
Photos:
- PBS NOVA: Dolphins: Close EncountersArchivedOctober 30, 2008, at theWayback Machine