115-479: The bottlenose dolphin is a toothed whale in the genus Tursiops . They are common, cosmopolitan members of the family Delphinidae , the family of oceanic dolphins . Molecular studies show the genus contains three species : the common bottlenose dolphin ( Tursiops truncatus ), the Indo-Pacific bottlenose dolphin ( Tursiops aduncus ), and Tamanend's bottlenose dolphin ( Tursiops erebennus ). Others, like
230-410: A marine sponge on their rostrum , presumably to protect it when searching for food on the sandy sea bottom. This has only been observed in this bay (first in 1997), and is predominantly practiced by females. A 2005 study showed mothers most likely teach the behavior to their offspring, evincing culture (behavior learned from other species members). Mud plume feeding is a feeding technique performed by
345-426: A broad range of sounds using nasal airsacs located just below the blowhole. Clicks are directional and are used for echolocation, often occurring in a short series called a click train. The click rate increases when approaching an object of interest. Toothed whale biosonar clicks are amongst the loudest sounds made by marine animals . The cetacean ear has specific adaptations to the marine environment. In humans,
460-444: A burst of air into the water and allowing it to rise to the surface, forming a ring, or swimming repeatedly in a circle and then stopping to inject air into the helical vortex currents thus formed. They also appear to enjoy biting the vortex rings, so that they burst into many separate bubbles and then rise quickly to the surface. Dolphins are known to use this method during hunting. Dolphins are also known to use tools. In Shark Bay ,
575-671: A change of water flow pattern from the infant which minimizes separation between the mother and infant, but also increases the mother's surface area and creates a drag for the swimmer. This also leaves less energy to use in swimming speed, foraging, and predator evasion. Adult males live mostly alone or in groups of two to three, and join pods for short periods of time. Adult females and young dolphins normally live in groups of up to 15 animals. Males give strong mutual support if other males help them, even if they are not friends. However, they live in fission-fusion societies of varying group size , within which individuals change associations, often on
690-583: A concentrated food source. Toothed whale The toothed whales (also called odontocetes , systematic name Odontoceti ) are a clade of cetaceans that includes dolphins , porpoises , and all other whales with teeth , such as beaked whales and the sperm whales . 73 species of toothed whales are described. They are one of two living groups of cetaceans, the other being the baleen whales (Mysticeti), which have baleen instead of teeth. The two groups are thought to have diverged around 34 million years ago (mya). Toothed whales range in size from
805-551: A daily or hourly basis. Group compositions are usually determined by sex, age, reproductive condition, familial relations and affiliation histories. In a dolphin community near Sarasota, Florida , the most common group types are adult females with their recent offspring, older subadults of both sexes, and adult males either alone or in bonded pairs. Smaller groups can join to form larger groups of 100 or more, and occasionally exceed 1,000. The social strategies of marine mammals such as bottlenose dolphins "provide interesting parallels" with
920-439: A few, like the orca , feed on mammals, such as pinnipeds . Males typically mate with multiple females every year, making them polygynous . Females mate every two to three years. Calves are typically born in the spring and summer, and females bear the responsibility for raising them, but more sociable species rely on the family group to care for calves. Many species, mainly dolphins, are highly sociable, with some pods reaching over
1035-422: A fish with its fluke, sometimes knocking it out of the water, using a strategy called "fish whacking". "Strand feeding" is an inherited feeding technique used by bottlenose dolphins near and around coastal regions of Georgia and South Carolina. When a pod finds a school of fish, they will circle the school and trap the fish in a mini whirlpool. Then, the dolphins will charge at the school and push their bodies up onto
1150-445: A human can: the dolphin can store 36 milliliters (ml) of oxygen per kg of body weight, compared with 20 ml per kg for humans. This is an adaptation to diving. The bottlenose dolphin typically rises to the surface to breathe through its blowhole two to three times per minute, although it can remain submerged for up to 20 minutes. Dolphins can breathe while "half-asleep". During the sleeping cycle, one brain hemisphere remains active, while
1265-550: A length of just over 4 m (13 ft). Its color varies considerably, is usually dark gray on the back and lighter gray on the flanks, but it can be bluish-grey, brownish-grey, or even nearly black, and is often darker on the back from the rostrum to behind the dorsal fin . This is called countershading and is a form of camouflage . Older dolphins sometimes have a few spots. Bottlenose dolphins can live for more than 40 years. Females typically live 5–10 years longer than males, with some females exceeding 60 years. This extreme age
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#17328586338741380-425: 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 identifying. 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. Research done on signature whistle usage by other dolphin species
1495-432: A mirror; then whether the animal shows signs of self-recognition is determined. In 1995, Marten and Psarakos used television to test dolphin self-awareness. They showed dolphins real-time footage of themselves, recorded footage, and another dolphin. They concluded that their evidence suggested self-awareness rather than social behavior. While this particular study has not been repeated since then, dolphins have since "passed"
1610-460: A more limited capacity for colour vision than most mammals. Most toothed whales have slightly flattened eyeballs, enlarged pupils (which shrink as they surface to prevent damage), slightly flattened corneas, and a tapetum lucidum ; these adaptations allow for large amounts of light to pass through the eye, and, therefore, a very clear image of the surrounding area. In water, a whale can see around 10.7 m (35 ft) ahead of itself, but they have
1725-454: A mud-flat, forcing the fish on the mud-flat, as well. The dolphins then crawl around on their sides, consuming the fish they washed up on shore. This happens only during low tides. One type of feeding behavior seen in bottlenose dolphins is mud ring feeding . Bottlenose dolphins conflict with small-scale coastal commercial fisheries in some Mediterranean areas. Common bottlenose dolphins are probably attracted to fishing nets because they offer
1840-410: A population of Indo-Pacific bottlenose dolphins put sponges on their beak to protect them from abrasions and sting ray barbs while foraging in the seafloor. This behaviour is passed on from mother to daughter, and it is only observed in 54 female individuals. Self-awareness is seen, by some, to be a sign of highly developed, abstract thinking. Self-awareness, though not well-defined scientifically,
1955-664: A practice known as "strand feeding". Groups of between two and six dolphins are regularly observed creating a bow wave to force the fish out of the water. The dolphins follow the fish, stranding themselves briefly, to eat their prey before twisting their bodies back and forth in order to slide back into the water. While initially documented in South Carolina and Georgia, strand feeding has also been observed in Louisiana, Texas, Baja California, Ecuador, and Australia. Some Mauritanian dolphins cooperate with human fishermen. The dolphins drive
2070-402: A rare form of self-decoration and social object use called grass-wearing. Self-decoration by wearing grass appears to be an attention-getting device rather than purely play and varies from a single blade to large clusters of grass. John's Pass dolphins self-decorate with grass primarily when they form new social groups or engage in procreative activities. Grass-wearing behavior among these dolphins
2185-728: A school of fish towards the shore, where humans await with nets. In the confusion of casting nets, the dolphins catch a large number of fish as well. Intraspecies cooperative foraging has also been observed. These behaviors may also be transmitted via teaching. Controversially, Rendell and Whitehead have proposed a structure for the study of cetacean culture. Similar cases have been observed in Laguna, Santa Catarina in Brazil since during 19th century as well. Near Adelaide , in South Australia , several bottlenose dolphins " tail-walk ", whereby they elevate
2300-450: A series of dimples known as vibrissal pits able to sense electric fields. Dolphins have sharp eyesight. The eyes are located at the sides of the head and have a tapetum lucidum , or reflecting membrane, at the back of the retina, which aids vision in dim light. Their horseshoe-shaped, double-slit pupils enable dolphins to have good vision both in air and underwater, despite the different indices of refraction of these media. When under water,
2415-402: A short time. The dolphin's search for food is aided by a form of sonar known as echolocation : it locates objects by producing sounds and listening for the echoes. Clicking sounds are emitted in a focused beam in front of the dolphin. When the clicking sounds hit an object in the water, like a fish or rock, they bounce off and come back to the dolphin as echoes. Echolocation tells the dolphins
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#17328586338742530-438: A small bulge sitting on top of its skull, whereas a sperm whale's head is filled mainly with the melon. Directional asymmetry in the skull has been seen amongst many generations, used for echolocation. This asymmetry is useful in focusing the use of bio sonar effectively when deep diving for prey. Odontocetes are well adapted to hear sounds at ultrasonic frequencies, as opposed to mysticetes who generally hear sounds within
2645-540: A small community of bottlenose dolphins over shallow seagrass beds (less than 1 m) in the Florida Keys in the United States. The behavior involves creation of a U-shaped plume of mud in the water column and then rushing through the plume to capture fish. Along the beaches and tidal marshes of South Carolina and Georgia in the United States, bottlenose dolphins cooperatively herd prey fish onto steep and sandy banks in
2760-570: A smaller range above water. They also have glands on the eyelids and outer corneal layer that act as protection for the cornea. The olfactory lobes are absent in toothed whales, and unlike baleen whales, they lack the vomeronasal organ , suggesting they have no sense of smell. Toothed whales are not thought to have a good sense of taste, as their taste buds are atrophied or missing altogether. However, some dolphins have preferences between different kinds of fish, indicating some sort of attachment to taste. Toothed whales are capable of making
2875-541: 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. These signature whistles are developed during a dolphin's first year; it continues to maintain the same sound throughout its lifetime. 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
2990-490: A synonym of T. truncatus , while T. nuuanu was recognized as a subspecies. In general, genetic variation between populations is significant, even among nearby populations. As a result of this genetic variation, other distinct species currently considered to be populations of common bottlenose dolphin are possible. Much of the discussion and doubts about its taxonomy is related to the existence of two ecotypes of bottlenose dolphins in many part of its distribution. For example,
3105-560: A thousand individuals. Once hunted for their products, cetaceans are now protected by international law. Some species are very intelligent . At the 2012 meeting of the American Association for the Advancement of Science , support was reiterated for a cetacean bill of rights, listing cetaceans as nonhuman persons . Besides whaling and drive hunting , they also face threats from bycatch and marine pollution. The baiji , for example,
3220-502: A uniquely identifying, frequency-modulated narrow-band signature vocalization ( signature whistle ). Signature whistles, which are in a higher frequency range than humans can hear, have an important role in facilitating mother–calf contact. In the Sarasota Dolphin Research Program's library of recordings were 19 female common bottlenose dolphins ( Tursiops truncatus ) producing signature whistles both with and without
3335-452: A way that the animal's body shape is restored, and infection of such large wounds are rare. Toothed whales are fully aquatic creatures, which means their birth and courtship behaviours are very different from terrestrial and semiaquatic creatures. Since they are unable to go onto land to calve, they deliver their young with the fetus positioned for tail-first delivery. This prevents the calf from drowning either upon or during delivery. To feed
3450-428: A year, dependency until one to two years, and maturity around seven to 10 years, all varying between the species. This mode of reproduction produces few offspring, but increases the survival probability of each one. Females, referred to as "cows", carry the responsibility of childcare, as males, referred to as "bulls", play no part in raising calves. Junior synonym Too Many Requests If you report this error to
3565-460: Is a local behavioral tradition that could constitute a cultural difference from other communities. Some researchers hypothesize that the number of nerve cells ( neurons ) in the cortex of the brain predicts intelligence in mammals . A 2019 study estimated the number of neurons in the cerebral cortex of three common bottlenose dolphins and found numbers ranging from 11.7 to 15.2 billion neurons. The human average being approximately 16 billion, this
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3680-408: Is believed to be the precursor to more advanced processes like metacognitive reasoning (thinking about thinking) that are typical of humans. Research in this field has suggested that cetaceans, among others, possess self-awareness. The most widely used test for self-awareness in animals is the mirror test , in which a temporary dye is placed on an animal's body, and the animal is then presented with
3795-467: Is considered functionally extinct by IUCN , with the last sighting in 2004, due to heavy pollution to the Yangtze River . Whales sometimes feature in literature and film, as in the great white sperm whale of Herman Melville 's Moby-Dick . Small odontocetes, mainly dolphins, are kept in captivity and trained to perform tricks. Whale watching has become a form of tourism around the world. The tube in
3910-575: Is energetically expensive. Males have large testes in relation to their body size. During the breeding season , males compete for access to females. Such competition can take the form of fighting other males or of herding females to prevent access by other males. Male Sarasota Bay common bottlenose dolphins with the defensive advantages of male pair-bonding range more widely than unpaired males, and encounter more unrelated females. In Shark Bay, male Indo-Pacific bottlenose dolphins have been observed working in pairs or larger groups to follow and/or restrict
4025-637: Is followed by rapid conception (1–2 months), whereas conception is delayed (2–9 months) if calf loss occurs between January and July. Weaning ages ranged from 2.7 to 8.0 years, but 66.7% (42 calves) were weaned by their fourth birthday. Females tended to wean mid-pregnancy. Group size was unrelated to water depth or female reproductive success, but reproductive success was predicted by water depth. Shallow water may allow mothers and calves to detect and avoid predatory sharks. Alternatively, or additionally, prey density may be higher in shallow water compared to deep water. Georgetown University professor Janet Mann argues
4140-440: Is herding, where a pod squeezes a school of fish into a small volume, known as a bait ball . Individual members then take turns plowing through the ball, feeding on the stunned fish. Coralling is a method where dolphins chase fish into shallow water to catch them more easily. Orcas and bottlenose dolphins have also been known to drive their prey onto a beach to feed on it, a behaviour known as beach or strand feeding. The shape of
4255-605: Is likely within the range found in the human population. Bottlenose dolphins have a lifespan of 40–60 years. Females can outlive males and live for 60 years or more. Dolphins start to reproduce aged 5 to 15 years. The bottlenose dolphin has a single blowhole located on the dorsal surface of the head consisting of a hole and a muscular flap. The flap is closed during muscle relaxation and opens during contraction. Dolphins are voluntary breathers, who must deliberately surface and open their blowholes to get air. They can store almost twice as much oxygen in proportion to their body weight as
4370-785: Is not a typical characteristic of most members of the species). Numerous investigations of bottlenose dolphin intelligence have been conducted, examining mimicry , use of artificial language , object categorization, and self-recognition . They can use tools (sponging; using marine sponges to forage for food sources they normally could not access) and transmit cultural knowledge from generation to generation, and their considerable intelligence has driven interaction with humans. Bottlenose dolphins gained popularity from aquarium shows and television programs such as Flipper . They have also been trained by militaries to locate sea mines or detect and mark enemy divers. In some areas, they cooperate with local fishermen by driving fish into their nets and eating
4485-412: Is one of the most accessible species for early cetologists , because it could be seen very close to land, inhabiting shallow coastal areas of Europe. Many of the findings that apply to all cetaceans were therefore first discovered in the porpoises. One of the first anatomical descriptions of the airways of the whales on the basis of a harbor porpoise dates from 1671 by John Ray. It nevertheless referred to
4600-449: Is only a single set of functional teeth (monophyodont dentition). Except for the sperm whale, most toothed whales are smaller than the baleen whales. The teeth differ considerably among the species. They may be numerous, with some dolphins bearing over 100 teeth in their jaws. At the other extreme are the narwhals with their single long tusks and the almost toothless beaked whales with tusk-like teeth only in males. In most beaked whales
4715-498: Is rare and less than 2% of all Bottlenose dolphins will live longer than 60 years. Bottlenose dolphins can jump to a height of 6 metres (20 feet) in the air. Their elongated upper and lower jaws form what is called a rostrum, or snout, which gives the animal its common name. The real, functional nose is the blowhole on top of its head; the nasal septum is visible when the blowhole is open. Bottlenose dolphins have 18 to 28 conical teeth on each side of each jaw. The flukes (lobes of
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4830-405: Is relatively limited. The research on other species done so far has yielded varied outcomes and inconclusive results. Sperm whales can produce three specific vocalisations: creaks, codas, and slow clicks. A creak is a rapid series of high-frequency clicks that sounds somewhat like a creaky door hinge. It is typically used when homing in on prey. A coda is a short pattern of 3 to 20 clicks that
4945-400: Is used in social situations to identify one another (like a signature whistle), but it is still unknown whether sperm whales possess individually specific coda repertoires or whether individuals make codas at different rates. Slow clicks are heard only in the presence of males (it is not certain whether females occasionally make them). Males make a lot of slow clicks in breeding grounds (74% of
5060-464: Is well adapted for both air and water, so much so that some can survive even if they are blind. Some species are well adapted for diving to great depths. Almost all have a layer of fat, or blubber , under the skin to keep warm in the cold water, with the exception of river dolphins . Toothed whales consist of some of the most widespread mammals, but some, as with the vaquita, are restricted to certain areas. Odontocetes feed largely on fish and squid, but
5175-519: Is well-adapted for hunting Arctic whales and calves. Bears are known to use sit-and-wait tactics, as well as active stalking and pursuit of prey on ice or water. Whales lessen the chance of predation by gathering in groups. This, however, means less room around the breathing hole as the ice slowly closes the gap. When out at sea, whales dive out of the reach of surface-hunting orca. Polar bear attacks on belugas and narwhals are usually successful in winter, but rarely inflict any damage in summer. For most of
5290-578: The Burrunan dolphin ( Tursiops (aduncus) australis ), may be alternately considered their own species or be subspecies of T. aduncus . Bottlenose dolphins inhabit warm and temperate seas worldwide, being found everywhere except for the Arctic and Antarctic Circle regions. Their name derives from the Latin tursio (dolphin) and truncatus for the truncated teeth (the type specimen was old and had worn down teeth; this
5405-461: The Port Phillip and Gippsland Lakes areas of Victoria , Australia, after research showed it was distinct from T. truncatus and T. aduncus , both in morphology and genetics. Also, evidence has been accumulating to validate the existence of a separate species, Lahille's bottlenose dolphin, T. gephyreus , that occurs in coastal waters of Argentina, Uruguay and southern Brazil. Other sources accept
5520-401: The artiodactyl order (even-toed ungulates). They are closely related to the hippopotamus , sharing a common ancestor that lived around 54 million years ago (mya). The primitive cetaceans, or archaeocetes , first took to the sea approximately 49 mya and became fully aquatic by 5–10 million years later. The ancestors of toothed whales and baleen whales diverged in the early Oligocene. This
5635-608: The colossal squid , octopuses , and fish like demersal rays , but their diet is mainly medium-sized squid . Some prey may be taken accidentally while eating other items. A study in the Galápagos found that squid from the genera Histioteuthis (62%), Ancistrocheirus (16%), and Octopoteuthis (7%) weighing between 12 and 650 grams (0.026 and 1.433 lb) were the most commonly taken. Battles between sperm whales and giant squid or colossal squid have never been observed by humans; however, white scars are believed to be caused by
5750-413: The middle ear works as an impedance equalizer between the outside air's low impedance and the cochlear fluid's high impedance. In whales, and other marine mammals, no great difference exists between the outer and inner environments. Instead of sound passing through the outer ear to the middle ear, whales receive sound through the throat, from which it passes through a low-impedance, fat-filled cavity to
5865-528: The 1.4 m (4 ft 7 in) and 54 kg (119 lb) vaquita to the 20 m (66 ft) and 100 t (98 long tons; 110 short tons) sperm whale . Several species of odontocetes exhibit sexual dimorphism , in that there are size or other morphological differences between females and males. They have streamlined bodies and two limbs that are modified into flippers. Some can travel at up to 20 knots. Odontocetes have conical teeth designed for catching fish or squid. They have well-developed hearing that
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#17328586338745980-453: The 1950s, no "dolphin language" has been found. However, Herman , Richards, and Wolz demonstrated comprehension of an artificial language by two bottlenose dolphins (named Akeakamai and Phoenix) in the period of skepticism toward animal language following Herbert Terrace 's critique. Cognitive abilities that have been investigated include concept formation , sensory skills, and mental representations. Such research has been ongoing since
6095-471: The 1970s. This includes: acoustic and behavioral mimicry, comprehension of novel sequences in an artificial language , memory , monitoring of self behavior, discrimination and matching, comprehension of symbols for various body parts, comprehension of pointing gestures and gaze (as made by dolphins or humans), mirror self-recognition , and numerical values. At least some wild bottlenose dolphins use tools. In Shark Bay , off Western Australia , dolphins place
6210-559: The Eastern Tropical Pacific bottlenose dolphin ( T. t. nuuanu ). The IUCN, on their Red List of endangered species, currently recognises only two species of bottlenose dolphins. The American Society of Mammalogists also recognizes only two species. While acknowledging the studies describing T. australis , it classifies it within T. aduncus . Some recent genetic evidence suggests the Indo-Pacific bottlenose dolphin belongs in
6325-543: The Pacific bottlenose dolphin ( T. t. gillii or T. gillii ), that inhabits the Pacific, and has a black line from the eye to the forehead. T. gillii , first described in 1873, is currently considered a junior synonym of T. truncatus . Additionally, T. nuuanu was described in 1911 for bottlenose dolphins along the Pacific coast in Central America. An analysis of T. gillii and T. nuuanu specimens supported T. gillii as
6440-434: The average human brain which averages 1,450 cm (88 in ) in mature males. The brain to body mass ratio in some odontocetes, such as belugas and narwhals, is second only to humans. Dolphins are known to engage in complex play behaviour , which includes such things as producing stable underwater toroidal air-core vortex rings or " bubble rings ". Two main methods of bubble ring production are: rapid puffing of
6555-663: The behaviour has continued through generations until 2022. A study conducted by the University of Chicago showed that bottlenose dolphins can remember whistles of other dolphins they had lived with after 20 years of separation. Each dolphin has a unique whistle that functions like a name, allowing the marine mammals to keep close social bonds. The new research shows that dolphins have the longest memory yet known in any species other than humans . The bottlenose dolphins of John's Pass in Boca Ciega Bay, St. Petersburg, Florida , exhibit
6670-451: The brain homologous to where they are found in humans, suggesting they perform a similar function. Brain size was previously considered a major indicator of the intelligence of an animal. Since most of the brain is used for maintaining bodily functions, greater ratios of brain to body mass may increase the amount of brain mass available for more complex cognitive tasks. Allometric analysis indicates that mammalian brain size scales around
6785-519: The brain. Bottlenose dolphins are able to detect salty, sweet, bitter ( quinine sulphate ), and sour ( citric acid ) tastes, but this has not been well-studied. Anecdotally, some individuals in captivity have been noted to have preferences for food fish types, although it is not clear if taste mediates this preference. In 2022, a study at the University of St Andrews in Scotland found that dolphins were able to identify their "friends" and family members by
6900-773: The child to pay attention, long-term bonding, and promoting the development of lifelong vocal learning , with parallels in these bottlenose dolphins in an example of convergent evolution . Researchers from the Bottlenose Dolphin Research Institute (BDRI), based in Sardinia (Italy) have now shown whistles and burst pulsed sounds are vital to the animals' social life and mirror their behaviors. The tonal whistle sounds (the most melodious ones) allow dolphins to stay in contact with each other (above all, mothers and offspring), and to coordinate hunting strategies. The burst-pulsed sounds (which are more complex and varied than
7015-514: The coastal form while the offshore form was retained in T. truncatus . The Society for Marine Mammalogy 's Committee on Taxonomy presently recognizes three species of bottlenose dolphin: T. truncatus , T. aduncus , and T. erebennus . They also recognize three subspecies of common bottlenose dolphin in addition to the nominotypical subspecies : the Black Sea bottlenose dolphin ( T. t. ponticus ), Lahille's bottlenose dolphin ( T. t. gephyreus ), and
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#17328586338747130-399: The concentration of myoglobin than haemoglobin. Before going on long dives, many toothed whales exhibit a behaviour known as sounding; they stay close to the surface for a series of short, shallow dives while building their oxygen reserves, and then make a sounding dive. Toothed whale eyes are relatively small for their size, yet they do retain a good degree of eyesight. Also, the eyes are on
7245-441: The dolphin to the sperm whale's spermaceti organ . These send out high-frequency clicks through the sound-modifying organs of the extramandibular fat body, intramandibular fat body and the melon . The melon consists of fat, and the skull of any such creature containing a melon will have a large depression. The melon size varies between species, the bigger it is, the more dependent they are on it. A beaked whale, for example, has
7360-409: The exception sperm whales), and eyes placed on the sides of their heads. Toothed whales range in size from the 4.5 ft (1.4 m) and 120 lb (54 kg) vaquita to the 20 m (66 ft) and 55 t (61-short-ton) sperm whale. Overall, they tend to be dwarfed by their relatives, the baleen whales (Mysticeti). Several species have sexual dimorphism, with the females being larger than
7475-499: The existence of two species: the common bottlenose dolphin ( T. truncatus ), found in coastal and oceanic habitats of most tropical to temperate oceans, and the Indo-Pacific bottlenose dolphin ( T. aduncus ), that lives in coastal waters around India , northern Australia, South China, the Red Sea , and the eastern coast of Africa. In 2011, a third distinct species was described, the Burrunan dolphin ( T. (aduncus) australis ), found in
7590-461: The eyeball's lens serves to focus light, whereas in the in-air environment, the typically bright light serves to contract the specialized pupil, resulting in sharpness from a smaller aperture (similar to a pinhole camera ). By contrast, a bottlenose's sense of smell is poor, because its blowhole, the analog to the nose, is closed when underwater and it opens only for breathing. Like other toothed whales , it has no olfactory nerves or olfactory lobe in
7705-510: The fact that the Tursiops dolphins might consist of more than one species, as there is extensive variation in color and morphology along its range. In the past, most studies used morphology to evaluate differences between and within species, but in the late 20th century, combining morphological and molecular genetics allowed much greater insight into this previously intractable problem. Since the late 1990s and early 2000s, most researchers acknowledged
7820-642: The females are not in their estrous cycles and cannot produce young, suggesting they may mate for pleasure . The gestation period averages 12 months. Births can occur at any time of year, although peaks occur in warmer months. The young are born in shallow water, sometimes assisted by a (possibly male) "midwife", and usually only a single calf is born. Twins are possible, but rare. Newborn bottlenose dolphins are 0.8 to 1.4 m (2.6 to 4.6 ft) long and weigh 9 to 30 kg (20 to 66 lb), with Indo-Pacific bottlenose dolphin infants being generally smaller than common bottlenose dolphin infants. To accelerate nursing,
7935-598: The fish that escape. Some encounters with humans are harmful to the dolphins: people hunt them for food, and dolphins are killed inadvertently as a bycatch of tuna fishing and by getting caught in crab traps . Bottlenose dolphins have the third largest encephalization levels of any mammal on Earth (humans have the largest, followed by Northern Right whale dolphins ), sharing close ratios with those of humans and other cetaceans , while being twice as high of other great apes . This more than likely contributes to their high intelligence . Scientists have been long aware of
8050-431: The floating cages in the farming area. Fish is one of the main items in the dolphin diet. They also eat shrimps, squid, mollusks, and cuttlefish, and only swallow the soft parts. They eat 22 pounds of fish a day. When they encounter a shoal of fish , they work as a team to herd them towards the shore to maximize the harvest. They also hunt alone, often targeting bottom-dwelling species. The bottlenose dolphin sometimes hits
8165-475: The front, and a tail fin. These flippers contain four digits. Although toothed whales do not possess fully developed hind limbs, some, such as the sperm whale, possess discrete rudimentary appendages, which may contain feet and digits. Toothed whales are fast swimmers in comparison to seals, which typically cruise at 5–15 knots, or 9–28 km/h (5.6–17.4 mph); the sperm whale, in comparison, can travel at speeds of up to 35 km/h (22 mph). The fusing of
8280-536: The genital slit. The ability to stow their reproductive organs (especially in males) allows for maximum hydrodynamics. The breeding season produces significant physiological changes in males. At that time, the testes enlarge, enabling them to hold more sperm. Large amounts of sperm allow a male to wash away the previous suitor's sperm, while leaving some of his own for fertilization. Also, sperm concentration markedly increases. Having less sperm for out-of-season social mating means it wastes less. This suggests sperm production
8395-588: The genus Stenella , since it is more like the Atlantic spotted dolphin ( Stenella frontalis ) than the common bottlenose dolphin. However, more recent studies indicate that this is a consequence of reticulate evolution (such as past hybridization between Stenella and ancestral Tursiops ) and incomplete lineage sorting , and thus support T . truncatus and T. aduncus belonging to the same genus. Bottlenose dolphins have been known to hybridize with other dolphin species. Hybrids with Risso's dolphin occur both in
8510-484: The harsh climate. Calves are born with only a thin layer of blubber, but some species compensate for this with thick lanugos . Toothed whales have also evolved the ability to store large amounts of wax esters in their adipose tissue as an addition to or in complete replacement of other fats in their blubber. They can produce isovaleric acid from branched chain fatty acids (BCFA). These adaptations are unique, are only in more recent, derived lineages and were likely part of
8625-551: The head, through which this kind fish takes its breath and spitting water, located in front of the brain and ends outwardly in a simple hole, but inside it is divided by a downward bony septum, as if it were two nostrils; but underneath it opens up again in the mouth in a void. –John Ray, 1671, the earliest description of cetacean airways In Aristotle 's time, the fourth century BC, whales were regarded as fish due to their superficial similarity. Aristotle, however, could already see many physiological and anatomical similarities with
8740-406: The inner ear. The ear is acoustically isolated from the skull by air-filled sinus pockets, which allow for greater directional hearing underwater. Odontocetes 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 in
8855-900: The large squid. A 2010 study suggests that female sperm whales may collaborate when hunting Humboldt squid . The orca is known to prey on numerous other toothed whale species. One example is the false killer whale . To subdue and kill whales, orcas continually ram them with their heads; this can sometimes kill bowhead whales , or severely injure them. Other times, they corral their prey before striking. They are typically hunted by groups of 10 or fewer orca, but they are seldom attacked by an individual. Calves are more commonly taken by orca, but adults can be targeted, as well. Groups even attack larger cetaceans such as minke whales , gray whales , and rarely sperm whales or blue whales . Other marine mammal prey species include nearly 20 species of seal , sea lion and fur seal . These cetaceans are targeted by terrestrial and pagophilic predators. The polar bear
8970-465: The lungs meets cold air, so it does not form in warmer climates, as with river dolphins. Almost all cetaceans have a thick layer of blubber , except for river dolphins. In species that live near the poles, the blubber can be as thick as 11 in (28 cm). This blubber can help with buoyancy, protection to some extent as predators would have a hard time getting through a thick layer of fat, energy for fasting during leaner times, and insulation from
9085-423: The males. One exception is with the sperm whale, which has males larger than the females. Odontocetes possess teeth with cementum cells overlying dentine cells. Unlike human teeth, which are composed mostly of enamel on the portion of the tooth outside of the gum, whale teeth have cementum outside the gum. Only in larger whales, where the cementum is worn away on the tip of the tooth, does enamel show. There
9200-431: The melon-shaped forehead, reflected off objects, and retrieved through the lower jaw. Skulls of Squalodon show evidence for the first hypothesized appearance of echolocation. Squalodon lived from the early to middle Oligocene to the middle Miocene , around 33-14 mya. Squalodon featured several commonalities with modern Odontocetes. The cranium was well compressed, the rostrum telescoped outward (a characteristic of
9315-403: The mirror test. Dolphins make a broad range of sounds using nasal airsacs located just below the blowhole. Roughly three categories of sounds can be identified: frequency modulated whistles, burst-pulsed sounds and clicks. Dolphins communicate with whistle-like sounds produced by vibrating connective tissue, similar to the way human vocal cords function, and through burst-pulsed sounds, though
9430-462: The modern parvorder Odontoceti ), giving Squalodon an appearance similar to that of modern toothed whales. However, it is thought unlikely that squalodontids are direct ancestors of living dolphins. Toothed whales have torpedo-shaped bodies with usually inflexible necks, limbs modified into flippers, no outer ears, a large tail fin, and bulbous heads (with the exception of the sperm whale family ). Their skulls have small eye orbits, long beaks (with
9545-416: The mother can eject milk from her mammary glands . The calf suckles for 18 months to up to 8 years, and continues to closely associate with its mother for several years after weaning. Females sexually mature at ages 5–13, males at ages 9–14. Females reproduce every two to six years. Reproduction is moderately seasonal (September–January), peaking from October to December. Calf loss between August and December
9660-427: The movement of a female for weeks at a time, waiting for her to become sexually receptive . These coalitions, also known as male reproductive alliances , will fight with other coalitions for control of females. Humans and bottlenose dolphins are the only species that share this type of "gang formation" habit as a form of cooperation. Mating occurs belly to belly. Dolphins have been observed engaging in intercourse when
9775-403: The nature and extent of that ability is not known. The clicks are directional and are for echolocation, often occurring in a short series called a click train. The click rate increases when approaching an object of interest. Dolphin echolocation clicks are amongst the loudest sounds made by marine animals. Bottlenose dolphins have been found to have signature whistles, a whistle that is unique to
9890-536: The neck vertebrae, while increasing stability when swimming at high speeds, decreases flexibility, rendering them incapable of turning their heads; river dolphins, however, have unfused neck vertebrae and can turn their heads. When swimming, toothed whales rely on their tail fins to propel them through the water. Flipper movement is continuous. They swim by moving their tail fin and lower body up and down, propelling themselves through vertical movement, while their flippers are mainly used for steering. Some species log out of
10005-416: The newborn, toothed whales, being aquatic, must squirt the milk into the mouth of the calf. Being mammals, they have mammary glands used for nursing calves; they are weaned around 11 months of age. This milk contains high amounts of fat which is meant to hasten the development of blubber; it contains so much fat, it has the consistency of toothpaste. Females deliver a single calf, with gestation lasting about
10120-536: The original sound. In larger groups, individual whistle sounds are less prominent. Dolphins tend to travel in pods, sometimes of up to 600 members. Cetaceans are known to communicate and therefore are able to teach, learn, cooperate, scheme, and grieve. The neocortex of many species of dolphins is home to elongated spindle neurons that, prior to 2007, were known only in hominids. In humans, these cells are involved in social conduct, emotions, judgement, and theory of mind. Dolphin spindle neurons are found in areas of
10235-560: The other hemisphere shuts down. The active hemisphere handles surfacing and breathing behavior. The daily sleeping cycle lasts for about 8 hours, in increments of minutes to hours. During the sleeping cycle, they remain near the surface, swimming slowly or "logging", and occasionally closing one eye. Both sexes have genital slits on the underside of their bodies. The male can retract and conceal his penis through his slit. The female's slit houses her vagina and anus. Females have two mammary slits, each housing one nipple , one on each side of
10350-662: The porpoise as a fish. Sperm whales (Physeteridae) [REDACTED] Dwarf sperm whales (Kogiidae) [REDACTED] South Asian river dolphins (Platanistidae) [REDACTED] Beaked whales (Ziphiidae) [REDACTED] Yangtze river dolphin (Lipotidae) [REDACTED] Pontoporiidae [REDACTED] Iniidae [REDACTED] Oceanic dolphins (Delphinidae) [REDACTED] Porpoises (Phocoenidae) [REDACTED] Belugas , narwhals (Monodontidae) [REDACTED] Toothed whales, as well as baleen whales, are descendants of land-dwelling mammals of
10465-435: The presence of their dependent calf. In all 19 cases, the mother dolphin changed the same signature whistle when the calf was present, by reaching a higher frequency, or using a wider frequency range. Similarly, humans use higher fundamental frequencies and a wider pitch range to inflect child–directed speech (CDS). This has rarely been discovered in other species. The researchers stated that CDS benefits for humans are cueing
10580-438: The range of infrasonic frequencies. Bottlenose dolphins have been found to have signature whistles unique to each individual. Dolphins use these whistles to communicate with one another by identifying an individual. It can be seen as the dolphin equivalent of a name for humans. Because dolphins generally live in groups, communication is necessary. Signal masking is when other similar sounds (conspecific sounds) interfere with
10695-615: The sensitivity of the sound receptor.) The interclick interval also decreases as the animal nears the target. Evidently, the dolphin waits for each click's echo before clicking again. Echolocation details, such as signal strength, spectral qualities, and discrimination, are well understood by researchers. Bottlenose dolphins are also able to extract shape information, suggesting they are able to form an "echoic image" or sound picture of their targets. They also have electroreception . The calves are born with two slender rows of whiskers along their snout, which fall off soon after birth, leaving behind
10810-410: The shape, size, speed, distance, and location of the object. To hear the returning echo, they have two small ear openings behind the eyes, but most sound waves are transmitted to the inner ear through the lower jaw. As the object of interest is approached, the echo becomes booming, and the dolphins adjust by decreasing the intensity of the emitted sounds. (This contrasts with bats and sonar, which reduce
10925-418: The sides of the head, so their vision consists of two fields, rather than a binocular view as humans have. When a beluga surfaces, its lenses and corneas correct the nearsightedness that results from the refraction of light; they contain both rod and cone cells, meaning they can see in both dim and bright light. They do, however, lack short wavelength-sensitive visual pigments in their cone cells, indicating
11040-475: The smaller species of dolphins, only a few of the larger sharks, such as the bull shark , dusky shark , tiger shark , and great white shark , are a potential risk, especially for calves. Dolphins can tolerate and recover from extreme injuries (including shark bites) although the exact methods used to achieve this are not known. The healing process is rapid and even very deep wounds do not cause dolphins to hemorrhage to death. Even gaping wounds restore in such
11155-423: The snout may correlate with tooth number and thus feeding mechanisms. The narwhal, with its blunt snout and reduced dentition, relies on suction feeding . Sperm whales usually dive between 300 and 800 metres (980 and 2,620 ft), and sometimes 1 to 2 kilometres (3,300 to 6,600 ft), in search of food. Such dives can last more than an hour. They feed on several species, notably the giant squid , but also
11270-494: The social strategies of elephants and chimpanzees. Bottlenose dolphins studied by Bottlenose Dolphin Research Institute researchers off the island of Sardinia show random social behavior while feeding, and their social behavior does not depend on feeding activity. In Sardinia, the presence of a floating marine fin-fish farm has been linked to a change in bottlenose dolphin distribution as a result of high fish density around
11385-525: The strong personal behavior among male calves is about bond formation and benefits the species in an evolutionary context. She cites studies showing these dolphins as adults are inseparable, and that early bonds aid protection, as well as in locating females. Female bottlenose dolphins have to expend additional energy in carrying out parental care, e.g. , infant-carrying behavior. Dolphins do not physically hold their infants but line up in an echelon position with infants swimming beside them. This position creates
11500-533: The tail) and dorsal fin are formed of dense connective tissue and do not contain bone or muscle . The dorsal fin usually shows phenotypic variations that help discriminate among populations. The animal propels itself by moving the flukes up and down. The pectoral flippers (at the sides of the body) are for steering; they contain bones homologous to the forelimbs of land mammals. A bottlenose dolphin discovered in Japan has two additional pectoral fins, or "hind legs", at
11615-637: The tail, about the size of a human's pair of hands. Scientists believe a mutation caused the ancient trait to reassert itself as a form of atavism . In colder waters, they have more body fat and blood, and are more suited to deeper diving. Typically, 18%–20% of their body weight is blubber. Most research in this area has been restricted to the North Atlantic Ocean . Bottlenose dolphins typically swim at 5 to 11 km/h (1.4 to 3.1 m/s), but are capable of bursts of up to 29 to 35 km/h (8.1 to 9.7 m/s). The higher speeds can only be sustained for
11730-477: The taste of their urine in the water. Bottlenose dolphins communicate through burst pulsed sounds, whistles, and body language. Examples of body language include leaping out of the water, snapping jaws, slapping the tail on the surface and butting heads. Sounds and gestures help keep track of other dolphins in the group, and alert other dolphins to danger and nearby food. Lacking vocal cords , they produce sounds using six air sacs near their blow hole. Each animal has
11845-501: The teeth are seen to erupt in the lower jaw, and primarily occurs at the males sexual maturity. Not all species are believed to use their teeth for feeding. For instance, the sperm whale likely uses its teeth for aggression and showmanship. Breathing involves expelling stale air from their one blowhole , forming an upward, steamy spout, followed by inhaling fresh air into the lungs. Spout shapes differ among species, which facilitates identification. The spout only forms when warm air from
11960-515: The terrestrial vertebrates, such as blood (circulation), lungs, uterus, and fin anatomy. His detailed descriptions were assimilated by the Romans, but mixed with a more accurate knowledge of the dolphins, as mentioned by Pliny the Elder in his Natural history . In the art of this and subsequent periods, dolphins are portrayed with a high-arched head (typical of porpoises) and a long snout. The harbor porpoise
12075-542: The time), both near the surface and at depth, which suggests they are primarily mating signals. Outside breeding grounds, slow clicks are rarely heard, and usually near the surface. All whales are carnivorous and predatory . Odontocetes, as a whole, mostly feed on fish and cephalopods , and then followed by crustaceans and bivalves . All species are generalist and opportunistic feeders. Some may forage with other kinds of animals, such as other species of whales or certain species of pinnipeds . One common feeding method
12190-425: The toothed whale lineage. Modern toothed whales do not rely on their sense of sight, but rather on their sonar to hunt prey. Echolocation also allowed toothed whales to dive deeper in search of food, with light no longer necessary for navigation, which opened up new food sources. Toothed whales (Odontocetes) echolocate by creating a series of clicks emitted at various frequencies. Sound pulses are emitted through
12305-449: The transition for species to become deeper divers as the families of toothed whales (Physeteridae, Kogiidae, and Ziphiidae) that have the highest quantities of wax esters and BCFAs in their blubber are also the species that dive the deepest and for the longest amount of time. Toothed whales have a two-chambered stomach similar in structure to terrestrial carnivores. They have fundic and pyloric chambers. Cetaceans have two flippers on
12420-425: The two ecotypes of the common bottlenose dolphin within the western North Atlantic are represented by the shallower water or coastal ecotype and the more offshore ecotype. Their ranges overlap, but they have been shown to be genetically distinct. In 2022, Costa et al. established morphologic, genetic, and evolutionary divergence between the two ecotypes in the western North Atlantic, resurrecting Tursiops erebennus for
12535-439: The two-thirds or three-quarters exponent of the body mass. Comparison of a particular animal's brain size with the expected brain size based on such allometric analysis provides an encephalization quotient that can be used as another indication of animal intelligence. Sperm whales have the largest brain mass of any animal on earth, averaging 8,000 cm (490 in ) and 7.8 kg (17 lb) in mature males, in comparison to
12650-436: The upper part of their bodies vertically out of the water, and propel themselves along the surface with powerful tail movements. Tail-walking mostly arises via human training in dolphinaria. In the 1980s, a female from the local population was kept at a local dolphinarium for three weeks, and the scientist suggests she copied the tail-walking behavior from other dolphins. Two other wild adult female dolphins copied it from her, and
12765-504: The water, which may allow them to travel faster. Their skeletal anatomy allows them to be fast swimmers. Most species have a dorsal fin . Most toothed whales are adapted for diving to great depths, porpoises are one exception. In addition to their streamlined bodies, they can slow their heart rate to conserve oxygen; blood is rerouted from tissue tolerant of water pressure to the heart and brain among other organs; haemoglobin and myoglobin store oxygen in body tissue; and they have twice
12880-450: The whistles) are used "to avoid physical aggression in situations of high excitement", such as when they are competing for the same piece of food, for example. The dolphins emit these strident sounds when in the presence of other individuals moving towards the same prey. The "least dominant" one soon moves away to avoid confrontation. Other communication uses about 30 distinguishable sounds, and although famously proposed by John C. Lilly in
12995-598: The wild and in captivity. The best known hybrid is the wholphin , a false killer whale -bottlenose dolphin hybrid. The wholphin is fertile, and two currently live at the Sea Life Park in Hawaii. The first was born in 1985 to a female bottlenose. Wholphins also exist in the wild. In captivity, a bottlenose dolphin and a rough-toothed dolphin hybridized. A common dolphin -bottlenose dolphin hybrid born in captivity lives at SeaWorld California. Other hybrids live in captivity around
13110-707: The world and in the wild, such as a bottlenose dolphin-Atlantic spotted dolphin hybrid. Bottlenose dolphins appeared during the Miocene . Known fossil species include Tursiops osennae (late Miocene to early Pliocene ) from the Piacenzian coastal mudstone, and Tursiops miocaenus (Miocene) from the Burdigalian marine sandstone, all in Italy. The bottlenose dolphin weighs an average of 300 kg (660 lb), but can range from 150 and 650 kg (330 and 1,430 lb). It can reach
13225-614: Was due to a change in the climate of the southern oceans that affected where the environment of the plankton that these whales ate. The adaptation of echolocation and enhanced fat synthesis in blubber occurred when toothed whales split apart from baleen whales, and distinguishes modern toothed whales from fully aquatic archaeocetes. This happened around 34 mya. Unlike toothed whales, baleen whales do not have wax ester deposits nor branched fatty chain acids in their blubber. Thus, more recent evolution of these complex blubber traits occurred after baleen whales and toothed whales split, and only in
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