Bottlenose Dolphin
Overview
Bottlenose dolphins, the genus Tursiops, are the most common and well-known members of the family Delphinidae, the family of oceanic dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

s. Recent molecular studies
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

 show the genus contains two species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

, the common bottlenose dolphin
Common Bottlenose Dolphin
Tursiops truncatus, commonly known as the Common Bottlenose Dolphin, is the most well-known species from the family Delphinidae.Common bottlenose dolphins are the most familiar dolphins due to the wide exposure they receive in captivity in marine parks, dolphinarias, in movies, and television...

 (Tursiops truncatus) and the Indo-Pacific bottlenose dolphin
Indo-Pacific Bottlenose Dolphin
The Indo-Pacific bottlenose dolphin is a species of bottlenose dolphin. The Indo-Pacific bottlenose dolphin grows to long, and weigh up to . It lives in the waters around India, northern Australia, South China, the Red Sea, and the eastern coast of Africa. Its back is dark grey and its belly...

 (Tursiops aduncus), instead of one. Research in 2011 revealed a third species, the Burrunan dolphin
Burrunan dolphin
The Burrunan dolphin is a recently-described species of bottlenose dolphin found in parts of Victoria, Australia. By size, the Burrunan dolphin is between the other two species of bottlenose dolphin and only around 150 individuals have been found in two locations.-Taxonomy:The species was formally...

 (Tursiops australis). They inhabit warm and temperate seas worldwide.

Bottlenose dolphins live in groups typically of 10–30 members, called pods, but group size varies from single individuals up to more than 1,000.
Encyclopedia
Bottlenose dolphins, the genus Tursiops, are the most common and well-known members of the family Delphinidae, the family of oceanic dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

s. Recent molecular studies
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

 show the genus contains two species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

, the common bottlenose dolphin
Common Bottlenose Dolphin
Tursiops truncatus, commonly known as the Common Bottlenose Dolphin, is the most well-known species from the family Delphinidae.Common bottlenose dolphins are the most familiar dolphins due to the wide exposure they receive in captivity in marine parks, dolphinarias, in movies, and television...

 (Tursiops truncatus) and the Indo-Pacific bottlenose dolphin
Indo-Pacific Bottlenose Dolphin
The Indo-Pacific bottlenose dolphin is a species of bottlenose dolphin. The Indo-Pacific bottlenose dolphin grows to long, and weigh up to . It lives in the waters around India, northern Australia, South China, the Red Sea, and the eastern coast of Africa. Its back is dark grey and its belly...

 (Tursiops aduncus), instead of one. Research in 2011 revealed a third species, the Burrunan dolphin
Burrunan dolphin
The Burrunan dolphin is a recently-described species of bottlenose dolphin found in parts of Victoria, Australia. By size, the Burrunan dolphin is between the other two species of bottlenose dolphin and only around 150 individuals have been found in two locations.-Taxonomy:The species was formally...

 (Tursiops australis). They inhabit warm and temperate seas worldwide.

Bottlenose dolphins live in groups typically of 10–30 members, called pods, but group size varies from single individuals up to more than 1,000. Their diet consists mainly of forage fish
Forage fish
Forage fish, also called prey fish or bait fish, are small fish which are preyed on by larger predators for food. Predators include other larger fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the food chain on plankton, often by filter feeding...

. Dolphins often work as a team to harvest fish schools
Shoaling and schooling
In biology, any group of fish that stay together for social reasons are said to be shoaling , and if, in addition, the group is swimming in the same direction in a coordinated manner, they are said to be schooling . In common usage, the terms are sometimes used rather loosely...

, but they also hunt individually. Dolphins search for prey primarily using echolocation
Animal echolocation
Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects...

, which is similar to sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...

. They emit clicking sounds and listen for the return echo to determine the location and shape of nearby items, including potential prey. Bottlenose dolphins also use sound for communication, including squeaks and whistles emitted from the blowhole and sounds emitted through body language, such as leaping from the water and slapping their tails on the water surface.

There have been numerous investigations of bottlenose dolphin intelligence. Research on bottlenose dolphins has examined mimicry, use of artificial language, object categorization and self-recognition. Their considerable intelligence has driven interaction with humans. Bottlenose dolphins are popular from aquarium
Aquarium
An aquarium is a vivarium consisting of at least one transparent side in which water-dwelling plants or animals are kept. Fishkeepers use aquaria to keep fish, invertebrates, amphibians, marine mammals, turtles, and aquatic plants...

 shows and television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...

 programs such as Flipper
Flipper (1964 TV series)
Flipper, from Ivan Tors Films in association with Metro-Goldwyn-Mayer Television, is an American television program first broadcast on NBC from September 19, 1964, until April 15, 1967. Flipper, a bottlenose dolphin, is the companion animal of Porter Ricks, Chief Warden at fictional Coral Key Park...

. 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 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
Cetacean bycatch
Cetacean bycatch is the incidental capture of non-target cetacean species by fisheries. Species which are seriously affected by this include dolphins, porpoises, and whales. Bycatch can be caused by entanglement in fishing nets and lines, or direct capture by hooks or in trawl nets.Cetacean bycatch...

 of tuna
Tuna
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...

 fishing.

Taxonomy

Scientists were long aware that Tursiops dolphins might consist of more than one species. Molecular genetics allowed much greater insight into this previously intractable problem. The consensus is there are two species, although a third distinct species was described in 2011:

  • The common bottlenose dolphin
    Common Bottlenose Dolphin
    Tursiops truncatus, commonly known as the Common Bottlenose Dolphin, is the most well-known species from the family Delphinidae.Common bottlenose dolphins are the most familiar dolphins due to the wide exposure they receive in captivity in marine parks, dolphinarias, in movies, and television...

     (T. truncatus), is found in most tropical to temperate oceans; color is grey, with the shade of grey varying among populations; it can be bluish-grey, brownish-grey, or even nearly black, and is often darker on the back from the rostrum
    Rostrum (anatomy)
    The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....

     to behind the dorsal fin
    Dorsal fin
    A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

    .
  • The Indo-Pacific bottlenose dolphin
    Indo-Pacific Bottlenose Dolphin
    The Indo-Pacific bottlenose dolphin is a species of bottlenose dolphin. The Indo-Pacific bottlenose dolphin grows to long, and weigh up to . It lives in the waters around India, northern Australia, South China, the Red Sea, and the eastern coast of Africa. Its back is dark grey and its belly...

     (T. aduncus), lives in the waters around India
    India
    India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

    , northern Australia
    Australia
    Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

    , South China
    China
    Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

    , the Red Sea
    Red Sea
    The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. In the north, there is the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez...

    , and the eastern coast of Africa
    Africa
    Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

    ; the back is dark-grey and the belly is lighter grey or nearly white with grey spots.
  • The Burrunan dolphin
    Burrunan dolphin
    The Burrunan dolphin is a recently-described species of bottlenose dolphin found in parts of Victoria, Australia. By size, the Burrunan dolphin is between the other two species of bottlenose dolphin and only around 150 individuals have been found in two locations.-Taxonomy:The species was formally...

     (T. australis), found in the Port Phillip
    Port Phillip
    Port Phillip Port Phillip Port Phillip (also commonly referred to as Port Phillip Bay or (locally) just The Bay, is a large bay in southern Victoria, Australia; it is the location of Melbourne. Geographically, the bay covers and the shore stretches roughly . Although it is extremely shallow for...

     and Gippsland Lakes
    Gippsland Lakes
    The Gippsland Lakes are a network of lakes, marshes and lagoons in east Gippsland, Victoria, Australia covering an area of about 600 km2. The largest of the lakes are Lake Wellington , Lake King and Lake Victoria. They are fed by the Avon, Thomson, Latrobe, Mitchell, Nicholson and Tambo...

     areas of Victoria
    Victoria (Australia)
    Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....

    , Australia
    Australia
    Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

    . Was described in September 2011 after research showed it was distinct from T. truncatus and T. aduncus.


The following are sometimes recognized as subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...

 of T. truncatus:
  • The Pacific bottlenose dolphin (T. gillii or T. truncatus gillii), lives in the Pacific, and has a black line from the eye to the forehead.
  • The Black Sea bottlenose dolphin (T. truncatus ponticus), lives in the Black Sea
    Black Sea
    The Black Sea is bounded by Europe, Anatolia and the Caucasus and is ultimately connected to the Atlantic Ocean via the Mediterranean and the Aegean seas and various straits. The Bosphorus strait connects it to the Sea of Marmara, and the strait of the Dardanelles connects that sea to the Aegean...

    .


There are two ecotype
Ecotype
In evolutionary ecology, an ecotype,Greek: οίκος = home and τύπος = type, coined by Göte Turesson in 1922 sometimes called ecospecies, describes a genetically distinct geographic variety, population or race within species , which is adapted to specific environmental conditions.Typically, ecotypes...

s of the common bottlenose dolphin within the western North Atlantic. These 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. They are not currently described, however, as separate species or subspecies. In general, there is significant genetic variation between populations, even among nearby populations. As a result of this genetic variation, it is possible there are other distinct species currently considered to be populations of common bottlenose dolphin.

Old scientific data do not distinguish among the two species, making it useless for determining structural differences between them. The IUCN lists both species as data deficient on their Red List of endangered species because of this issue.

Some recent genetic evidence suggests the Indo-Pacific bottlenose belongs in the genus Stenella
Stenella
Stenella is a genus of aquatic mammals in Delphinidae, the family informally known as the oceanic dolphins.Currently five species are recognised in this genus:*Pantropical Spotted Dolphin, S. attenuata*Atlantic Spotted Dolphin, S. frontalis...

, since it is more like the Atlantic spotted dolphin
Atlantic Spotted Dolphin
The Atlantic Spotted Dolphin is a dolphin found in the Gulf Stream of the North Atlantic Ocean. Older members of the species have a very distinctive spotted coloration all over their body.-Taxonomy:...

 (Stenella frontalis) than the common bottlenose.
Dolphins belong to the suborder Odontocetae, which groups all toothed whale species, the largest of which is the sperm whale
Sperm Whale
The sperm whale, Physeter macrocephalus, is a marine mammal species, order Cetacea, a toothed whale having the largest brain of any animal. The name comes from the milky-white waxy substance, spermaceti, found in the animal's head. The sperm whale is the only living member of genus Physeter...

. The sister branch of Odontocetae includes all baleen-producing species (Mysticetae), the largest of which is the blue whale
Blue Whale
The blue whale is a marine mammal belonging to the suborder of baleen whales . At in length and or more in weight, it is the largest known animal to have ever existed....

.

Hybrids

Bottlenose dolphins have been known to hybridize with other dolphin species. Hybrids with Risso's dolphin
Risso's Dolphin
Risso's dolphin is the only species of dolphin in the genus Grampus.-Taxonomy:Risso's dolphin is named after Antoine Risso, whose description formed the basis of the first public description of the animal, by Georges Cuvier, in 1812...

 occur both in the wild and in captivity. The best known is the wolphin
Wolphin
A Wholphin or Wolphin is a rare hybrid, born from a mating of a female Bottlenose Dolphin with a male false killer whale . The name implies a hybrid of whale and dolphin, although taxonomically, both are within the "oceanic dolphin" family, which is within the "toothed whale" suborder...

, a false killer whale
False Killer Whale
The False Killer Whale is a cetacean, and the third largest member of the oceanic dolphin family . It lives in temperate and tropical waters throughout the world. As its name implies, the False Killer Whale shares characteristics, such as appearance, with the more widely known Orca...

-bottlenose dolphin hybrid. The wolphin is fertile, and two currently live at the Sea Life Park in Hawaii
Hawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

. The first was born in 1985 to a female bottlenose. Wolphins also exist in the wild. In captivity, a bottlenose dolphin and a rough-toothed dolphin
Rough-toothed Dolphin
The Rough-toothed dolphin is species of dolphin that can be found in deep warm and tropical waters around the world.The species was first described by Georges Cuvier in 1823...

 hybridized. A common dolphin
Common dolphin
The common dolphin is the name given to two species of dolphin making up the genus Delphinus.Prior to the mid-1990s, most taxonomists only recognised one species in this genus, the common dolphin Delphinus delphis...

-bottlenose dolphin hybrid born in captivity lives at SeaWorld
SeaWorld
SeaWorld is a United States chain of marine mammal parks, oceanariums, and animal theme parks owned by SeaWorld Parks & Entertainment. The parks feature captive orca, sea lion, and dolphin shows and zoological displays featuring various other marine animals. There are operations in Orlando,...

 California. Other hybrids live in captivity around the world and in the wild, such as a bottlenose dolphin-Atlantic spotted dolphin
Atlantic Spotted Dolphin
The Atlantic Spotted Dolphin is a dolphin found in the Gulf Stream of the North Atlantic Ocean. Older members of the species have a very distinctive spotted coloration all over their body.-Taxonomy:...

 hybrid.

Description

They are grey, varying from dark grey at the top near the dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

 to very light grey and almost white at the underside. This countershading
Countershading
Countershading, or Thayer's Law, is a form of camouflage. Countershading, in which an animal’s pigmentation is darker dorsally, is often thought to have an adaptive effect of reducing conspicuous shadows cast on the ventral region of an animal’s body...

 makes it hard to see, both from above and below, when swimming
Aquatic locomotion
Swimming is biologically propelled motion through a liquid medium. Swimming has evolved a number of times in a range of organisms ranging from arthropods to fish to molluscs.-Evolution of swimming:...

. Adult
Adult
An adult is a human being or living organism that is of relatively mature age, typically associated with sexual maturity and the attainment of reproductive age....

s range in length between 2 and 4 m (6.6 and 13.1 ft), and in weight between 150 and 650 kg (330.7 and 1,433 lb). Males are on average slightly longer and considerably heavier than female
Female
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...

s. In most parts of the world, the adult's length is about 2.5 metres (8.2 ft), with weight ranges between 200 and 300 kg (440.9 and 661.4 lb).
Their size varies considerably with habitat. Except in the eastern Pacific, dolphins in warmer, shallower waters tend to be smaller than those in cooler
Cooler
A cooler, cool box, portable ice chest, chilly bin , or esky most commonly is an insulated box used to keep food or drink cool. Ice cubes are most commonly placed in it to help the things inside stay cool...

 pelagic waters. A survey in the Moray Firth
Moray Firth
The Moray Firth is a roughly triangular inlet of the North Sea, north and east of Inverness, which is in the Highland council area of north of Scotland...

 in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

, the world's second northernmost dolphin population, recorded an average adult length of just under 4 metres (13.1 ft) compared with a 2.5 metres (8.2 ft) average in a population off the coast
Coast
A coastline or seashore is the area where land meets the sea or ocean. A precise line that can be called a coastline cannot be determined due to the dynamic nature of tides. The term "coastal zone" can be used instead, which is a spatial zone where interaction of the sea and land processes occurs...

 of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

.

Bottlenose dolphins can live for more than 40 years. However, one study of a population off Sarasota, Florida
Sarasota, Florida
Sarasota is a city located in Sarasota County on the southwestern coast of the U.S. state of Florida. It is south of the Tampa Bay Area and north of Fort Myers...

 indicated an average lifespan of 20 years or less.

Anatomy

Their elongated upper and lower jaws form what is called a rostrum
Rostrum (anatomy)
The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....

, or snout, which gives the animal its common name. The real, functional nose is the blowhole on top of its head; the nasal septum
Nasal septum
The nasal septum separates the left and right airways in the nose, dividing the two nostrils.It is depressed by the Depressor septi nasi muscle.-Composition:The fleshy external end of the nasal septum is sometimes also called columella....

 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 the tail) and dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

 are formed of dense connective tissue
Connective tissue
"Connective tissue" is a fibrous tissue. It is one of the four traditional classes of tissues . Connective Tissue is found throughout the body.In fact the whole framework of the skeleton and the different specialized connective tissues from the crown of the head to the toes determine the form of...

 and do not contain bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...

 or muscle
Muscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

. 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
Homology (biology)
Homology forms the basis of organization for comparative biology. In 1843, Richard Owen defined homology as "the same organ in different animals under every variety of form and function". Organs as different as a bat's wing, a seal's flipper, a cat's paw and a human hand have a common underlying...

 to the forelimbs of land mammals. A bottlenose dolphin was discovered in Japan that has two additional pectoral fins, or "hind legs", at the tail, about the size of a human
Human
Humans are the only living species in the Homo genus...

's pair of hands. Scientists believe a mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...

 caused the ancient trait to reassert itself as a form of atavism
Atavism
Atavism is the tendency to revert to ancestral type. In biology, an atavism is an evolutionary throwback, such as traits reappearing which had disappeared generations before. Atavisms can occur in several ways...

.

Physiology and senses

In colder waters, they have more body fat and blood, and are more suited to deeper diving. Typically, 18%–20% of their bodyweight is blubber. Most research in this area has been restricted to the North Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

.
Bottlenose dolphins typically swim at 5–11 km/h (1.4–3.1 m/s), but are capable of bursts of up to 29–35 km/h (8.1–9.7 m/s). The higher speeds can only be sustained for a short time.

Echolocation

The dolphin's search for food is aided by a form of sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...

 known as echolocation
Animal echolocation
Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects...

: they locate objects by producing sounds and listening for the echo. A broadband burst pulse of clicking sounds is emitted in a focused beam in front of the dolphin. 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 grows louder, and the dolphins adjust by decreasing the intensity of the emitted sounds. (This contrasts with bat
Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...

s and sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...

, which reduce 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.

Eyesight

Dolphins have sharp eyesight. The eyes are located at the sides of the head and have a tapetum lucidum
Tapetum lucidum
The tapetum lucidum is a layer of tissue in the eye of many vertebrate animals....

, or reflecting membrane at the back of the retina, which aids vision in dim light. Their horseshoe-shaped, double-slit pupil enables dolphins to have good vision both in air and underwater, despite the different densities of these media. When underwater, 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
Pinhole camera
A pinhole camera is a simple camera without a lens and with a single small aperture – effectively a light-proof box with a small hole in one side. Light from a scene passes through this single point and projects an inverted image on the opposite side of the box...

).

Smell

By contrast, a bottlenose's sense of smell is poor, because its blowhole, the analogue to the nose, is closed when underwater and opens only for breathing. It has no olfactory nerves or olfactory lobe in the brain. Bottlenose dolphins are able to detect salty, sweet, bitter (quinine
Quinine
Quinine is a natural white crystalline alkaloid having antipyretic , antimalarial, analgesic , anti-inflammatory properties and a bitter taste. It is a stereoisomer of quinidine which, unlike quinine, is an anti-arrhythmic...

 sulphate), and sour (citric acid
Citric acid
Citric acid is a weak organic acid. It is a natural preservative/conservative and is also used to add an acidic, or sour, taste to foods and soft drinks...

) tastes, but this has not been well-studied. Anecdotally, some animals in captivity have been noted to have preferences for food fish types, although it is not clear if taste mediates this preference.

Communication

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 a uniquely identifying, frequency-modulated narrow-band signature vocalization (signature whistle).

Researchers from the Bottlenose Dolphin Research Institute (BDRI), based in Sardinia
Sardinia
Sardinia is the second-largest island in the Mediterranean Sea . It is an autonomous region of Italy, and the nearest land masses are the French island of Corsica, the Italian Peninsula, Sicily, Tunisia and the Spanish Balearic Islands.The name Sardinia is from the pre-Roman noun *sard[],...

 (Italy) have now shown whistles and burst pulsed sounds are vital to the animals' social life and mirror their behaviours.

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 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 in order to avoid confrontation.

Other communication uses about 30 distinguishable sounds, and although famously proposed by John Lilly
John C. Lilly
John Cunningham Lilly was an American physician, neuroscientist, psychoanalyst, psychonaut, philosopher and writer....

 in the 1950s, no "dolphin language" has been found. However, Herman
Louis Herman
Louis Herman is a researcher of dolphin sensory abilities, dolphin cognition, and humpback whales. He is currently professor in the Department of Psychology and a cooperating faculty member of the Department of Oceanography at the University of Hawaii at Manoa...

, Richards, & Wolz demonstrated comprehension of an artificial language by two bottlenose dolphins (named Akeakamai
Akeakamai
Akeakamai was a female Atlantic bottlenose dolphin, who along with a companion female dolphin named Phoenix, as well as tankmates Elele and Hiapo, were the subjects of Louis Herman's animal language studies at the Kewalo Basin Marine Mammal Laboratory in Honolulu, Hawaii...

 and Phoenix) in the period of skepticism toward animal language
Animal language
Animal language is the modeling of human language in non human animal systems. While the term is widely used, researchers agree that animal languages are not as complex or expressive as human language....

 following Herbert Terrace's critique.

Intelligence

Cognition

Cognitive
Cognition
In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...

 abilities investigated include concept formation
Concept learning
Concept learning, also known as category learning, concept attainment, and concept formation, is largely based on the works of the cognitive psychologist Jerome Bruner...

, sensory skills, and mental representations. Such research has been ongoing since the 1970s. This includes:
  • acoustic and behavioral mimicry,
  • comprehension of novel sequences in an artificial language
    Animal language
    Animal language is the modeling of human language in non human animal systems. While the term is widely used, researchers agree that animal languages are not as complex or expressive as human language....

    ,
  • memory
    Memory
    In psychology, memory is an organism's ability to store, retain, and recall information and experiences. Traditional studies of memory began in the fields of philosophy, including techniques of artificially enhancing 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.

Tool use and culture

At least some wild bottlenose dolphins use tools. In Shark Bay
Shark Bay
Shark Bay is a World Heritage listed bay in Western Australia. The term may also refer to:* the locality of Shark Bay, now known as Denham* Shark Bay Marine Park* Shark Bay , a shark exhibit at Sea World, Gold Coast, Australia* Shire of Shark Bay...

, dolphins place a marine sponge on their rostrum
Rostrum (anatomy)
The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....

, 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 almost exclusively by females. Sea otter
Sea Otter
The sea otter is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between 14 and 45 kg , making them the heaviest members of the weasel family, but among the smallest marine mammals...

s are the only other marine mammalian tool users. A 2005 study showed mothers most likely teach the behavior to their daughters, evincing culture
Culture
Culture is a term that has many different inter-related meanings. For example, in 1952, Alfred Kroeber and Clyde Kluckhohn compiled a list of 164 definitions of "culture" in Culture: A Critical Review of Concepts and Definitions...

 (behavior learned from other species members). Some Mauritania
Mauritania
Mauritania is a country in the Maghreb and West Africa. It is bordered by the Atlantic Ocean in the west, by Western Sahara in the north, by Algeria in the northeast, by Mali in the east and southeast, and by Senegal in the southwest...

n dolphins cooperate with human fishermen. The dolphins drive 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.

Near Adelaide
Adelaide
Adelaide is the capital city of South Australia and the fifth-largest city in Australia. Adelaide has an estimated population of more than 1.2 million...

, in South Australia
South Australia
South Australia is a state of Australia in the southern central part of the country. It covers some of the most arid parts of the continent; with a total land area of , it is the fourth largest of Australia's six states and two territories.South Australia shares borders with all of the mainland...

, three bottlenose dolphins 'tail-walk', whereby they elevate 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 have now copied it from her.

Cortical neurons

Some researchers theorize mammalian intelligence correlates to the number of nerve cells (neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...

s) in the cortex of the brain
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...

. Bottlenose dolphins have about 5.8 billion cortical neurons, placing them between chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...

s at 6.2 billion and gorilla
Gorilla
Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...

s at 4.3 billion. (Humans have 11.5 billion.) However, after Homo sapiens, the species with the highest number of cortical neurons and synapses is the elephant.

Respiration and sleep

The bottlenose dolphin has a single blowhole
Blowhole (biology)
In biology, a blowhole is the hole at the top of a cetacean's head through which the animal breathes air. It is homologous with the nostril of other mammals. As whales reach the water surface to breathe, they will forcefully expel air through the blowhole. Not only is air expelled, but mucus and...

 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 a human can: the dolphin can store 36 millilitres of oxygen per kilogram of body weight, compared with 20 millilitres per kilogram 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 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.

Reproduction

Both genders have genital slits on the underside of their bodies. The male can retract and conceal its penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...

 through its slit. The female's slit houses its vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...

 and anus. Females have two mammary slits, each housing one nipple
Nipple
In its most general form, a nipple is a structure from which a fluid emanates. More specifically, it is the projection on the breasts or udder of a mammal by which breast milk is delivered to a mother's young. In this sense, it is often called a teat, especially when referring to non-humans, and...

, one on each side of 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, testes enlarge, enabling it 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 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. In Shark Bay
Shark Bay
Shark Bay is a World Heritage listed bay in Western Australia. The term may also refer to:* the locality of Shark Bay, now known as Denham* Shark Bay Marine Park* Shark Bay , a shark exhibit at Sea World, Gold Coast, Australia* Shire of Shark Bay...

, male bottlenose dolphins have been observed working in pairs or larger groups to follow and/or restrict the movement of a female for weeks at a time, waiting for her to become sexually receptive. These coalitions will fight with other coalitions for control of females.

Mating occurs belly to belly. Dolphins have been observed engaging in intercourse when the females are not in their estrus cycles and cannot produce young, as well as when they can. The gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....

 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 between 0.8–1.4 m (2.6–4.6 ft) and 9–30 kg (19.8–66.1 lb), with Indo-Pacific bottlenose dolphin infants being generally smaller than common bottlenose dolphin infants. To accelerate nursing, the mother can eject milk from her mammary gland
Mammary gland
A mammary gland is an organ in mammals that produces milk to feed young offspring. Mammals get their name from the word "mammary". In ruminants such as cows, goats, and deer, the mammary glands are contained in their udders...

s. The calf suckles
Lactation
Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process occurs in all female mammals, however it predates mammals. In humans the process of feeding milk is called breastfeeding or nursing...

 for 18 to 20 months, 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. Georgetown University
Georgetown University
Georgetown University is a private, Jesuit, research university whose main campus is in the Georgetown neighborhood of Washington, D.C. Founded in 1789, it is the oldest Catholic university in the United States...

 professor Janet Mann argues 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.

Social interaction

Adult males live mostly alone or in groups of two to three, and join pods for short periods of time. Adult female and young dolphins normally live in groups of up to 15 animals. However, they live in fission-fusion societies
Fission-fusion society
In primatology, a fission-fusion society is one in which the social group, e.g. bonobo collectives of 100-strong, sleep in one locality together, but forage in small groups going off in different directions during the day. This form of social organization occurs in several other species of...

 of varying group size
Group size measures
Many animals, including humans, tend to live in groups, herds, flocks, bands, packs, shoals, or colonies of conspecific individuals. The size of these groups, as expressed by the number of participant individuals, is an important aspect of their social environment...

, within which individuals change associations, often on 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
Sarasota, Florida
Sarasota is a city located in Sarasota County on the southwestern coast of the U.S. state of Florida. It is south of the Tampa Bay Area and north of Fort Myers...

, the most common group types are adults 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 the social strategies of elephants and chimpanzees.

Bottlenose dolphins studied by Bottlenose Dolphin Research Institute
Bottlenose Dolphin Research Institute
The 'Bottlenose Dolphin Research Institute' is a marine science and education center, committed toconserving the diversity and integrity of marine life to meet the needs of current and future generations...

 researchers off the island of Sardinia
Sardinia
Sardinia is the second-largest island in the Mediterranean Sea . It is an autonomous region of Italy, and the nearest land masses are the French island of Corsica, the Italian Peninsula, Sicily, Tunisia and the Spanish Balearic Islands.The name Sardinia is from the pre-Roman noun *sard[],...

 show random social behaviour while feeding, and their social behaviour 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 the floating cages in the farming area.

Feeding

Its diet consists mainly of small fish, crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s, and squid
Squid
Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...

. Although this varies by location, many populations share an appetite for fish from the mullet
Mullet (fish)
The mullets or grey mullets are a family and order of ray-finned fish found worldwide in coastal temperate and tropical waters, and in some species in fresh water. Mullets have served as an important source of food in Mediterranean Europe since Roman times...

 family, the tuna and mackerel
Scombridae
Scombridae is the family of the mackerels, tunas, and bonitos, and thus includes many of the most important and familiar food fishes. The family consists of about 55 species in 15 genera and two subfamilies...

 family, and the drum and croaker
Sciaenidae
Sciaenidae is a family of fish commonly called drums, croakers, or hardheads for the repetitive throbbing or drumming sounds they make...

 family. Its cone-like teeth serve to grasp, but do not chew food. 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 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 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.

Some foraging behaviors are found only in certain habitats or regions. Mud plume feeding is an example. This behavior is performed by a small community of bottlenose dolphins over shallow seagrass beds (<1m) in the Florida Keys. The behavior involves creation of a U-shaped plume of mud in the water column and then rushing through the plume to capture fish.

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 a concentrated food source.

Relations with other species

Dolphins exhibit altruistic behaviour toward other sea creatures. On Mahia Beach, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

 on 10 March 2008, two pygmy sperm whale
Pygmy Sperm Whale
The Pygmy Sperm Whale is one of three species of toothed whale in the sperm whale family. They are not often sighted at sea, and most of what is known about them comes from the examination of stranded specimens.-Taxonomy:...

s, a female and calf, stranded on the beach. Rescuers, including Department of Conservation officer Malcolm Smith, attempted to refloat them four times. Shortly, a playful bottlenose dolphin known to local residents as Moko arrived and, after apparently vocalizing at the whales, led them 200 metres (656.2 ft) along a sandbar to the open sea, saving them from imminent euthanasia.

The bottlenose dolphin can behave aggressively. Males fight for rank and access to females. During mating season, males compete vigorously with each other through displays of toughness and size, with a series of acts such as head-butting. They display aggression towards shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

s and smaller dolphin species. At least one population, off Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

, has practiced infanticide
Infanticide (zoology)
In animals, infanticide involves the killing of young offspring by a mature animal of its own species, and is studied in zoology, specifically in the field of ethology. Ovicide is the analogous destruction of eggs. Although human infanticide has been widely studied, the practice has been observed...

, and also has attacked and killed harbour porpoise
Harbour Porpoise
The harbour porpoise is one of six species of porpoise. It is one of the smallest marine mammals. As its name implies, it stays close to coastal areas or river estuaries, and as such, is the most familiar porpoise to whale watchers. This porpoise often ventures up rivers, and has been seen...

s. University of Aberdeen
University of Aberdeen
The University of Aberdeen, an ancient university founded in 1495, in Aberdeen, Scotland, is a British university. It is the third oldest university in Scotland, and the fifth oldest in the United Kingdom and wider English-speaking world...

 researchers say the dolphins do not eat their victims, but are simply competing for food. However Dr. Read of Duke University, a porpoise expert researching similar cases of porpoise killings occurred in Virginia in 1996 and 1997 holds a different view. He states that dolphins and porpoises feed on different types of fish, thus food competition is an unlikely cause of the killings. Similar behaviour has been observed in Ireland.

The bottlenose dolphin sometimes forms mixed species groups with other species from the dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

 family, particularly larger species such as the short-finned pilot whale
Short-finned Pilot Whale
The Short-finned Pilot Whale is one of the two species of cetacean in the genus Globicephala. It is part of the oceanic dolphin family , though its behaviour is closer to that of the larger whales....

, the false killer whale
False Killer Whale
The False Killer Whale is a cetacean, and the third largest member of the oceanic dolphin family . It lives in temperate and tropical waters throughout the world. As its name implies, the False Killer Whale shares characteristics, such as appearance, with the more widely known Orca...

 and Risso's dolphin
Risso's Dolphin
Risso's dolphin is the only species of dolphin in the genus Grampus.-Taxonomy:Risso's dolphin is named after Antoine Risso, whose description formed the basis of the first public description of the animal, by Georges Cuvier, in 1812...

. They also interact with smaller species, such as the Atlantic spotted dolphin
Atlantic Spotted Dolphin
The Atlantic Spotted Dolphin is a dolphin found in the Gulf Stream of the North Atlantic Ocean. Older members of the species have a very distinctive spotted coloration all over their body.-Taxonomy:...

 and the rough-toothed dolphin
Rough-toothed Dolphin
The Rough-toothed dolphin is species of dolphin that can be found in deep warm and tropical waters around the world.The species was first described by Georges Cuvier in 1823...

. While interactions with smaller species are sometimes affiliative, they can also be hostile.

Predators

Some large shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....

 species, such as the tiger shark
Tiger shark
The tiger sharks, Galeocerdo cuvier, is a species of requiem shark and the only member of the genus Galeocerdo. Commonly known as sea tigers, tiger sharks are relatively large macropredators, capable of attaining a length of over . It is found in many tropical and temperate waters, and is...

, the dusky shark
Dusky shark
The dusky shark is a species of requiem shark, family Carcharhinidae, occurring in tropical and warm-temperate continental seas worldwide. A generalist apex predator, the dusky shark can be found from the coast to the outer continental shelf and adjacent pelagic waters, and has been recorded from...

, the great white shark
Great white shark
The great white shark, scientific name Carcharodon carcharias, also known as the great white, white pointer, white shark, or white death, is a large lamniform shark found in coastal surface waters in all major oceans. It is known for its size, with the largest individuals known to have approached...

 and the bull shark
Bull shark
The bull shark, Carcharhinus leucas, also known as Zambezi shark or unofficially known as Zambi in Africa and Nicaragua shark in Nicaragua, is a shark common worldwide in warm, shallow waters along coasts and in rivers...

, prey on the bottlenose dolphin, especially calves. The bottlenose dolphin is capable of defending itself by charging the predator; dolphin 'mobbing' behavior of sharks can occasionally prove fatal for the shark. Targeting a single adult dolphin can be dangerous for a shark of similar size. Certain (but not all) killer whale (orca) populations may also prey on dolphins, but this seems rare, and other orcas may swim with dolphins. Swimming in pods allows dolphins to better defend themselves against predators. Bottlenose dolphins either use complex evasive strategies to outswim their predators, or mobbing techniques to battle the predator to death or force it to flee.

Interaction

The species sometimes shows curiosity towards humans in or near water. Occasionally, they rescue injured divers by raising them to the surface. They also do this to help injured members of their own species. In November 2004, a dramatic report of dolphin intervention came from New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. Four lifeguards, swimming 100 metres (328.1 ft) off the coast near Whangarei
Whangarei
Whangarei, pronounced , is the northernmost city in New Zealand and the regional capital of Northland Region. Although commonly classified as a city, it is officially part of the Whangarei District, administered by the Whangarei District Council a local body created in 1989 to administer both the...

, were approached by a shark (reportedly a great white shark
Great white shark
The great white shark, scientific name Carcharodon carcharias, also known as the great white, white pointer, white shark, or white death, is a large lamniform shark found in coastal surface waters in all major oceans. It is known for its size, with the largest individuals known to have approached...

). Bottlenose dolphins herded the swimmers together and surrounded them for forty minutes, preventing the shark from attacking, as they slowly swam to shore.

In coastal regions, dolphins run the risk of colliding with boats. Researchers of the Bottlenose Dolphin Research Institute
Bottlenose Dolphin Research Institute
The 'Bottlenose Dolphin Research Institute' is a marine science and education center, committed toconserving the diversity and integrity of marine life to meet the needs of current and future generations...

 first quantified data about solitary bottlenose dolphin diving behavior in the presence and absence of boats. Dolphins responded more to tourist than fishing vessels. Driving behavior, speed, engine type and separation distance all affect dolphin safety.

Bottlenose dolphins perform in many aquaria, generating much controversy. Some animal welfare
Animal welfare
Animal welfare is the physical and psychological well-being of animals.The term animal welfare can also mean human concern for animal welfare or a position in a debate on animal ethics and animal rights...

 activists claim the dolphins do not have adequate space or receive adequate care or stimulation. However, others counter that the dolphins are properly cared for and enjoy interacting with humans.

Eight bottlenose dolphins that lived at the Marine Life Aquarium in Gulfport, Mississippi
Gulfport, Mississippi
Gulfport is the second largest city in Mississippi after the state capital Jackson. It is the larger of the two principal cities of the Gulfport-Biloxi, Mississippi Metropolitan Statistical Area, which is included in the Gulfport-Biloxi-Pascagoula, Mississippi Combined Statistical Area. As of the...

 were swept away from their aquarium pool during Hurricane Katrina
Hurricane Katrina
Hurricane Katrina of the 2005 Atlantic hurricane season was a powerful Atlantic hurricane. It is the costliest natural disaster, as well as one of the five deadliest hurricanes, in the history of the United States. Among recorded Atlantic hurricanes, it was the sixth strongest overall...

. They were later rescued in the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...

.

Therapies for handicapped children can include interactions with bottlenose dolphins.
The military of the United States
United States armed forces
The United States Armed Forces are the military forces of the United States. They consist of the Army, Navy, Marine Corps, Air Force, and Coast Guard.The United States has a strong tradition of civilian control of the military...

 and Russia train bottlenose dolphins as military dolphin
Military dolphin
A military dolphin is a dolphin trained for military uses. The United States and Russian militaries have trained and employed oceanic dolphins for several reasons. Such military dolphins have been trained to rescue lost naval swimmers or to locate underwater mines.The U.S. Navy trains dolphins and...

s for wartime tasks, such as locating sea mines and detecting enemy divers. The USA's program is the U.S. Navy Marine Mammal Program
U.S. Navy Marine Mammal Program
The U.S. Navy Marine Mammal Program is a program administered by the U.S. Navy which studies the military use of marine mammals—principally Bottlenose Dolphins and California Sea Lions—and trains animals to perform tasks such as ship and harbor protection, mine detection and clearance, and...

, located in San Diego, California
San Diego, California
San Diego is the eighth-largest city in the United States and second-largest city in California. The city is located on the coast of the Pacific Ocean in Southern California, immediately adjacent to the Mexican border. The birthplace of California, San Diego is known for its mild year-round...

.

Commercial 'dolphin encounter' enterprises and tours operate in many countries. In addition to such endeavors, the animals swim with and surface near surfers at the beach.

In the town of Laguna in south Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, a pod of bottlenose dolphins drives fish towards fishermen who stand at the beach in shallow waters. One dolphin then rolls over, after which the fishermen throw out their nets. The dolphins feed on the escaping fish. The dolphins were not trained for this behavior; the collaboration began before 1847. Similar cooperative fisheries also exist in Mauritania
Mauritania
Mauritania is a country in the Maghreb and West Africa. It is bordered by the Atlantic Ocean in the west, by Western Sahara in the north, by Algeria in the northeast, by Mali in the east and southeast, and by Senegal in the southwest...

, Africa.

Cultural Influence

The popular television show Flipper
Flipper (1964 TV series)
Flipper, from Ivan Tors Films in association with Metro-Goldwyn-Mayer Television, is an American television program first broadcast on NBC from September 19, 1964, until April 15, 1967. Flipper, a bottlenose dolphin, is the companion animal of Porter Ricks, Chief Warden at fictional Coral Key Park...

, created by Ivan Tors
Ivan Tors
Ivan Tors was a Hungarian playwright, film director, screenwriter, and film and television producer with an emphasis on non-violent but exciting science fiction, underwater filmed television and films, and films about animals...

, portrayed a bottlenose dolphin in a friendly relationship with two boys, Sandy and Bud. A seagoing Lassie
Lassie (1954 TV series)
Lassie is an American television series that follows the adventures of a female Rough Collie named Lassie and her companions, human and animal. The show was the creation of producer Robert Maxwell and animal trainer Rudd Weatherwax and was televised from September 12, 1954, to March 24, 1973...

, Flipper understood English and was a hero: "Go tell Dad we're in trouble, Flipper! Hurry!" The show's theme song contains the lyric no one you see / is smarter than he. The television show was based on a 1963 film
Flipper (1963 film)
Flipper is an American feature film released on August 14, 1963 written by Ricou Browning and Jack Cowden. Produced by Ivan Tors and directed by James B. Clark, it portrays a 12-year old boy living with his parents on the Florida Keys, who befriends an injured wild dolphin...

, and was remade as a feature film in 1996
Flipper (1996 film)
Flipper is a 1996 remake of the 1963 film of the same name, starring Paul Hogan and Elijah Wood. The movie is about a boy who has to spend the summer with his uncle Porter , who lives in the Florida Keys...

, starring Elijah Wood
Elijah Wood
Elijah Jordan Wood is an American actor. He made his film debut with a minor part in Back to the Future Part II , then landed a succession of larger roles that made him a critically acclaimed child actor by age 9. He is best known for his high-profile role as Frodo Baggins in Peter Jackson's...

 and Paul Hogan
Paul Hogan
Paul Hogan, AM is an Australian actor best known for his role as Michael "Crocodile" Dundee from the Crocodile Dundee film series, for which he won a Golden Globe award.-Early life and career:...

, as well as a second series running from 1995–2000, starring Jessica Alba
Jessica Alba
Jessica Marie Alba is an American television and film actress. She began her television and movie appearances at age 13 in Camp Nowhere and The Secret World of Alex Mack . Alba rose to prominence as the lead actress in the television series Dark Angel...

.

Other television appearances by bottlenose dolphins include Dolphin Cove, seaQuest DSV
SeaQuest DSV
seaQuest DSV is an American science fiction television series created by Rockne S. O'Bannon. It originally aired on NBC between 1993 and 1996. In its final season, it was renamed seaQuest 2032. Set in "the near future", seaQuest mixes high drama with realistic scientific fiction...

, and The Penguins of Madagascar
The Penguins of Madagascar
The Penguins of Madagascar is an American CGI animated television series airing on Nickelodeon. It stars nine characters from the DreamWorks Animation animated film Madagascar: The penguins Skipper , Kowalski , Private , and Rico ; the lemurs King Julien , Maurice , and Mort...

, in which a dolphin, Doctor Blowhole, is a villain. In the HBO movie Zeus and Roxanne
Zeus and Roxanne
Zeus and Roxanne is a 1997 family comedy/adventure film directed by George T. Miller. The film revolves around the friendship between the title characters, a dog and a dolphin, respectively. The film stars Steve Guttenberg and Kathleen Quinlan.-Cast:...

, a female bottlenose dolphin befriends a male dog, and in Bermuda Triangle, a girl named Annie (played by Lisa Jakub
Lisa Jakub
Lisa Jakub is a Canadian-American actress, best known for her roles in Mrs. Doubtfire and Independence Day.-Early life and career:...

) swims with dolphins. Human and dolphin interaction segments are featured on Sesame Street
Sesame Street
Sesame Street has undergone significant changes in its history. According to writer Michael Davis, by the mid-1970s the show had become "an American institution". The cast and crew expanded during this time, including the hiring of women in the crew and additional minorities in the cast. The...

and in a Halloween
Halloween
Hallowe'en , also known as Halloween or All Hallows' Eve, is a yearly holiday observed around the world on October 31, the night before All Saints' Day...

 episode of The Simpsons
The Simpsons
The Simpsons is an American animated sitcom created by Matt Groening for the Fox Broadcasting Company. The series is a satirical parody of a middle class American lifestyle epitomized by its family of the same name, which consists of Homer, Marge, Bart, Lisa and Maggie...

.

Dolphin Tale, directed by Charles Martin Smith
Charles Martin Smith
Charles Martin Smith is an American film actor, writer, and director.-Early life:Smith was born in Van Nuys, California. His father, Frank Smith, was a film cartoonist and animator, while his uncle Paul J. Smith was an animator as well as a director for the Walter Lantz Studios...

, starring Nathan Gamble
Nathan Gamble
Nathan Gamble is an American child actor who made his feature film debut in Babel , for which he was nominated for a 2007 Young Artist Award....

, Ashley Judd
Ashley Judd
Ashley Judd is an American television and film actress, who has played lead roles in films including Ruby in Paradise, Kiss the Girls, Double Jeopardy, Where the Heart Is and High Crimes...

, Harry Connick, Jr.
Harry Connick, Jr.
Joseph Harry Fowler Connick, Jr. is an American singer, big-band leader/conductor, pianist, actor, and composer. He has sold over 25 million albums worldwide. Connick is ranked among the top 60 best-selling male artists in the United States by the Recording Industry Association of America, with...

, Morgan Freeman
Morgan Freeman
Morgan Freeman is an American actor, film director, aviator and narrator. He is noted for his reserved demeanor and authoritative speaking voice. Freeman has received Academy Award nominations for his performances in Street Smart, Driving Miss Daisy, The Shawshank Redemption and Invictus and won...

, and Kris Kristofferson
Kris Kristofferson
Kristoffer "Kris" Kristofferson is an American musician, actor, and writer. He is known for hits such as "Me and Bobby McGee", "For the Good Times", "Sunday Mornin' Comin' Down", and "Help Me Make It Through the Night"...

, is based on the real-life story of the dolphin Winter
Winter (dolphin)
Winter is a bottlenose dolphin at the Clearwater Marine Aquarium in Clearwater, Florida, widely known for having a prosthetic tail. She is the subject of the film Dolphin Tale, a dramatization of her story. Winter was found off the coast of Florida in December 2005, caught in a crab trap, which...

, who was rescued from a crab trap in December 2005 and lost her tail, but has learned to swim with a prosthetic one.

Bottlenose dolphins have appeared in novels. In The Hitchhiker's Guide to the Galaxy
The Hitchhiker's Guide to the Galaxy
The Hitchhiker's Guide to the Galaxy is a science fiction comedy series created by Douglas Adams. Originally a radio comedy broadcast on BBC Radio 4 in 1978, it was later adapted to other formats, and over several years it gradually became an international multi-media phenomenon...

and one of its sequels, So Long, and Thanks For All the Fish
So Long, and Thanks for All the Fish
So Long, and Thanks for All the Fish is the fourth book of the Hitchhiker's Guide to the Galaxy "trilogy" written by Douglas Adams. Its title is the message left by the dolphins when they departed Planet Earth just before it was demolished to make way for a hyperspace bypass, as described in The...

, the dolphins try to warn humans of Earth's impending destruction, but their behavior was misinterpreted as playful acrobatics
Acrobatics
Acrobatics is the performance of extraordinary feats of balance, agility and motor coordination. It can be found in many of the performing arts, as well as many sports...

. Bottlenose dolphins are central to David Brin
David Brin
Glen David Brin, Ph.D. is an American scientist and award-winning author of science fiction. He has received the Hugo, Locus, Campbell and Nebula Awards.-Biography:...

's series of Uplift Universe
Uplift Universe
The Uplift Universe is a fictional universe created by science fiction writer David Brin. A central feature in this universe is the process of biological uplift.His books which take place in this universe:* Sundiver...

 novels, particularly Startide Rising
Startide Rising
Startide Rising is a 1983 science fiction novel by David Brin and the second book of six set in his Uplift Universe . It earned both Hugo and Nebula Awards for Best Novel...

, where they are one of the four Earth species (along with chimpanzee
Chimpanzee
Chimpanzee, sometimes colloquially chimp, is the common name for the two extant species of ape in the genus Pan. The Congo River forms the boundary between the native habitat of the two species:...

s, gorilla
Gorilla
Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...

s, and dog
Dog
The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

s) to have been 'uplifted
Biological uplift
In science fiction, uplift is the development or transformation of animals into an intelligent race by other, already-intelligent beings. The concept appears in David Brin's Uplift series and other science fiction works.-History of the concept:...

' to sentience
Sentience
Sentience is the ability to feel, perceive or be conscious, or to have subjective experiences. Eighteenth century philosophers used the concept to distinguish the ability to think from the ability to feel . In modern western philosophy, sentience is the ability to have sensations or experiences...

. Bottlenose dolphins are primary characters in Anne McCaffrey
Anne McCaffrey
Anne Inez McCaffrey was an American-born Irish writer, best known for her Dragonriders of Pern series. Over the course of her 46 year career she won a Hugo Award and a Nebula Award...

's Dragonriders of Pern
Dragonriders of Pern
Dragonriders of Pern is a science fiction series written primarily by the late American-Irish author Anne McCaffrey, who initiated it in 1967. Beginning 2003, her middle child Todd McCaffrey has written Pern novels, both solo and jointly with Anne. The series comprises 22 novels and several short...

series, especially The Dolphins of Pern
The Dolphins of Pern
The Dolphins of Pern is a science fiction novel by the American-Irish author Anne McCaffrey. It was the thirteenth book published in the Dragonriders of Pern series by Anne or her son Todd McCaffrey ....

. Bottlenose dolphins are incorporated into the science fiction video game series Ecco the Dolphin
Ecco the Dolphin (series)
Ecco the Dolphin is the collective name given to a series of action/adventure science fiction video games developed by Novotrade International and published by Sega. They were originally developed for the Mega Drive/Genesis and Dreamcast video game consoles, but have since been ported to numerous...

. Delphineus, a dolphin, is featured in the video game EcoQuest: The Search for Cetus, helping the boy, Adam, to find the sea king Cetus (a sperm whale), as well as assisting in cleaning up the underwater environment where he lives. Two dolphins appeared in the film Jaws 3-D
Jaws 3-D
Jaws 3-D is a 1983 thriller film directed by Joe Alves and starring Dennis Quaid, Bess Armstrong, Lea Thompson and Louis Gossett, Jr...

protecting Kay Morgan, the marine biologist, from shark attacks.

The Miami Dolphins
Miami Dolphins
The Miami Dolphins are a Professional football team based in the Miami metropolitan area in Florida. The team is part of the Eastern Division of the American Football Conference in the National Football League...

 NFL franchise uses the bottlenose dolphin as its mascot and team logo.

Factual descriptions of the dolphins date back into antiquity – the writings of Aristotle
Aristotle
Aristotle was a Greek philosopher and polymath, a student of Plato and teacher of Alexander the Great. His writings cover many subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, linguistics, politics, government, ethics, biology, and zoology...

, Oppian
Oppian
Oppian or Oppianus was the name of the authors of two didactic poems in Greek hexameters, formerly identified, but now generally regarded as two different persons: Oppian of Corycus in Cilicia; and Oppian of Apamea in Syria.-Oppian of Corycus:Oppian of Corycus in Cilicia, who flourished in the...

 and Pliny the Elder
Pliny the Elder
Gaius Plinius Secundus , better known as Pliny the Elder, was a Roman author, naturalist, and natural philosopher, as well as naval and army commander of the early Roman Empire, and personal friend of the emperor Vespasian...

 all mention the species.

Threats

Bottlenose dolphins are still killed in dolphin drive hunts
Dolphin drive hunting
Dolphin drive hunting, also called dolphin drive fishing, is a method of hunting dolphins and occasionally other small cetaceans by driving them together with boats and then usually into a bay or onto a beach. Their escape is prevented by closing off the route to the open sea or ocean with boats...

 for their meat or to eliminate competition for fish. Bottlenose dolphins (and several other dolphin species) often travel with tuna
Tuna
Tuna is a salt water fish from the family Scombridae, mostly in the genus Thunnus. Tuna are fast swimmers, and some species are capable of speeds of . Unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red coloration derives from myoglobin, an...

, and can get caught in tuna nets, which can kill the dolphins. Boycott
Boycott
A boycott is an act of voluntarily abstaining from using, buying, or dealing with a person, organization, or country as an expression of protest, usually for political reasons...

s of tuna products led to the concept of "dolphin-safe" labeling for fishing methods that avoid endangering dolphins.

The man-made chemical perfluorooctanesulfonic acid (PFOS) may be compromising the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

 of bottlenose dolphins. PFOS affects the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

 of male mice at a concentration of 91.5 ppb, while PFOS has been reported in bottlenose dolphins in excess of 1 ppm. High levels of metal contaminants have been measured in tissues in many areas of the globe. A recent study found high levels of cadmium
Cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Similar to zinc, it prefers oxidation state +2 in most of its compounds and similar to mercury it shows a low...

 and mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

 in bottlenose dolphins from South Australia, levels which were later found to be associated with kidney malformations, indicating possible health effects of high metal concentrations in dolphins.

Conservation

Bottlenose dolphins are not endangered. Their future is stable because of their abundance and adaptability. However, specific populations are threatened due to various environmental changes. The population in the Moray Firth
Moray Firth
The Moray Firth is a roughly triangular inlet of the North Sea, north and east of Inverness, which is in the Highland council area of north of Scotland...

 in Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 is estimated to consist of around 150 animals, and is declining by around 6% per year from harassment, traumatic injury, water pollution and reduction in food availability. Likewise, an isolated population in Doubtful Sound, New Zealand, is in decline due to calf loss coincident to an increase in warm freshwater discharge into the fjord. Less local climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

, such as increasing water temperature may also play a role but has never been shown to be the case.

In U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 waters, hunting and harassing of marine mammals is forbidden in almost all circumstances.

See also

  • Unihemispheric slow-wave sleep
    Unihemispheric slow-wave sleep
    Unihemispheric slow-wave sleep , also termed asymmetric slow-wave sleep , is characterized by slow-wave activity in one hemisphere of the brain while a low voltage EEG, characteristic of wakefulness, is present in the other. The phenomenon has been observed in a number of terrestrial and aquatic as...

  • Audiograms in mammals
  • Cetacean intelligence
    Cetacean intelligence
    Cetacean intelligence denotes the cognitive capabilities of the Cetacea order of mammals, which includes whales, porpoises, and dolphins.-Brain size:...

  • Dolphinarium
    Dolphinarium
    A dolphinarium is an aquarium for dolphins. The dolphins are usually kept in a large pool, though occasionally they may be kept in pens in the open sea, either for research or for public performances...

  • The Cove (film)

Research organizations

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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