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The common bottlenose dolphin or Atlantic bottlenose dolphin (''Tursiops truncatus'') is a wide-ranging marine mammal of the family Delphinidae. The common bottlenose dolphin is a very familiar dolphin due to the wide exposure it gets in captivity in marine parks and
dolphinarium A dolphinarium is an aquarium for dolphins. The dolphins are usually kept in a pool, though occasionally they may be kept in pens in the open sea, either for research or public performances. Some dolphinariums consist of one pool where dolphins pe ...
s, and in movies and television programs.Leatherwood, S., & Reeves, R. (1990). ''The Bottlenose Dolphin''. San Diego: Academic Press, Inc., It is the largest species of the beaked dolphins. It inhabits temperate and tropical oceans throughout the world, and is absent only from polar waters.Klinowska, M. (1991). ''Dolphins, Porpoises and Whales of the World: The IUCN Red Data Book''. Gland, Switzerland, U.K.: IUCN, While formerly known simply as the bottlenose dolphin, this term is now applied to the genus ''Tursiops'' as a whole. As considerable genetic variation has been described within this species, even between neighboring populations, many experts think additional species may be recognized.


Taxonomy

Until 1998, all bottlenose dolphins were considered one species ''T. truncatus.'' That year, the
Indo-Pacific bottlenose dolphin The Indo-Pacific bottlenose dolphin (''Tursiops aduncus'') is a species of bottlenose dolphin. This dolphin grows to long, and weighs up to . It lives in the waters around India, northern Australia, South China, the Red Sea, and the eastern ...
(''T. aduncus'') was recognized as a separate species. The two species are thought to have split during the mid-
Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
, about 1 million years ago. Currently, three common bottlenose dolphin subspecies are recognized: :''T. t. truncatus'', the nominate subspecies :''T. t. ponticus'', or the Black Sea bottlenose dolphin :''T. t. gephyreus'', or Lahille’s bottlenose dolphin Bottlenose dolphins along the southern California and
Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...
coasts were previously recognized as the Pacific bottlenose dolphin, ''T. t. gillii''. The name has since been reclassified as a
junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linn ...
of ''Tursiops truncatus''. A 2020 study identified four distinct lineages within ''T. truncatus'', each of which could be a distinct subspecies: a lineage native to the coastal regions of the western
North Atlantic The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe a ...
(off the coast of
North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and th ...
), an offshore lineage found worldwide in
pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...
ecosystems, a lineage native to the
Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on ...
, and a lineage restricted to the
Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Rom ...
(previously described as ''T. truncatus ponticus''). The study noted only weak differentiation between the Black Sea and Mediterranean lineages, and found them to form a sister group to the offshore lineage, indicating that they likely descended from offshore bottlenoses that colonized the Mediterranean and Black Seas. The clade containing the offshore, Mediterranean, and Black Sea populations was sister to the western North Atlantic lineage, indicating deep divergence between the two.


Description

Common bottlenose dolphins are grey, and between long, and weigh between .American Cetacean Society Fact Sheet �
Bottlenose Dolphin
Males are generally larger and heavier than females. In most parts of the world, adult length is between ; weight ranges between .Jenkins, J. (2009

Animal Diversity Web.
Dolphins have a short and well-defined snout that looks like an old-fashioned gin bottle, which is the source for their common name. Like all whales and dolphins, though, the snout is not a true nose; the nose instead evolved into the blowhole on the top of their heads. Their necks are more flexible than other dolphins' due to five of their seven vertebrae not being fused together like in other dolphins.


Intelligence

The common bottlenose dolphin has a larger brain than humans. Many investigations of bottlenose intelligence include tests of mimicry, use of artificial language, object categorization, and self-recognition. This intelligence has driven considerable interaction with humans. The common bottlenose dolphin is popular in aquarium shows and television programs such as '' Flipper''. It has also been trained for military uses such as locating sea mines or detecting and marking enemy divers, as for example in the
U.S. Navy Marine Mammal Program The U.S. Navy Marine Mammal Program (NMMP) 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 an ...
. In some areas, they cooperate with local fishermen by driving fish toward the fishermen and eating the fish that escape the fishermen's nets.


Ecology and behavior

As a very social species, the common bottlenose dolphin lives in groups called pods that typically number about 15 individuals, but group size varies from pairs of dolphins to over 100 or even occasionally over 1,000 animals for short periods of time. The types of groups include: nursery groups, juvenile groups, and groups of adult males.


Diet

Its diet consists mainly of eels, squid, shrimp and a wide variety of fishes. It does not chew its food, instead swallowing it whole. Dolphin pods often work as a team to harvest schools of fish, though they also hunt individually. Dolphins search for
prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
primarily using echolocation, which is a form of
sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on o ...
. The diet of common bottlenose dolphin pods varies depending on area. Along the U.S. Atlantic coast, the main prey includes Atlantic croakers (''Micropogonias undulatus''),
spot Spot or SPOT may refer to: Places * Spot, North Carolina, a community in the United States * The Spot, New South Wales, a locality in Sydney, Australia * South Pole Traverse, sometimes called the South Pole Overland Traverse People * Spot (produ ...
(''Leiostomus xanthurus'') and American silver perch (''Bairdiella chrysoura''), while in South Africa, African massbankers ('' Trachurus delagoa''), olive grunters (''Pomadasys olivaceus''), and pandora (''
Pagellus bellottii ''Pagellus bellottii'', the red pandora, ) is present in the eastern Atlantic, from the Strait of Gibraltar to Angola, and the Canary Islands. It is also recorded in the Mediterranean Sea since 1960. This demersal species is commonly found betwee ...
'') are common bottlenose dolphin's typical prey. According to combined stomach content and stable isotope analyses in the
Gulf of Cádiz The Gulf of Cádiz ( es, Golfo de Cádiz, pt, Golfo de Cádis) is the arm of the Atlantic Ocean between Cabo de Santa Maria, the southernmost point of mainland Portugal and Cape Trafalgar at the western end of the Strait of Gibraltar. Two m ...
, although European conger (''Conger conger'') and European hake (''Merluccius merluccius'') are most important prey of common bottlenose dolphins, mass-balance isotopic mixing model (MixSIAR), using δ13C and δ15N showns that Sparidae species; seabreams ('' Diplodus annularis'' and '' D. bellottii''), rubberlip grunt (''Plectorhinchus mediterraneus''), and common pandora, (''Pagellus erythrinus'')) and a mixture of other species including European hake, mackerels (''
Scomber colias Atlantic chub mackerel (''Scomber colias''), also known as Tinker mackerel, is a pelagic schooling species of mackerel found in the Atlantic Ocean, the Mediterranean Sea, and the Black Sea. It was originally thought to be a subspecies of the ...
'', '' S. japonicus'' and '' S. scombrus''), European conger, red bandfish (''Cepola macrophthalma'') and
European pilchard The European pilchard (''Sardina pilchardus'') is a species of ray-finned fish in the monotypic genus ''Sardina''. The young of the species are among the many fish that are sometimes called sardines. This common species is found in the northeast ...
(''Sardina pilchardus'') are the assimilated diet. Research indicates that the type and range of fish in a dolphin's diet can have a significant impact on its health and metabolism.


Communication

Dolphins also use sound for communication, including squeaks emitted from the blowhole, whistles emitted from nasal sacs below the blowhole, and sounds emitted through body language, such as leaping from the water and slapping their tails on the water. The dolphins address each other individually through matched whistling, where individuals respond to whistles of other dolphins by using the same whistle. Their heads contain an oily substance that both acts as an acoustic lens and protects the brain case. They emit clicking sounds and listen for the return echoes to determine the location and shape of nearby items, including potential prey.


Reproduction

Mating behavior of bottlenose dolphin is polygamous. Although they can breed throughout the year, it mostly occurs in spring. Males form alliances to seek an estrous female. For a chance to mate with the female, males separate the female from her home range. Females bear a calf every three to six years. After a year-long gestation period, females bear a single calf. Newborn calves are between long and weigh between . They can live as long as 40–50 years. The calf suckling lasts between 18 and 20 months. Sexual maturity varies by population, and ranges from 5–14 years of age; sexual maturity occurs between 8 and 13 years for males and 5 to 10 years for females.


Life expectancy

The average life expectancy of common bottlenose dolphins is about 17 years old, but in captivity they have been known to live to up to 51 years old.


Distribution

The common bottlenose dolphin can be found in temperate, subtropical, and tropical oceans around the world. The global population has been estimated at 600,000. Some bottlenose populations live closer to the shore (inshore populations) and others live further out to sea (offshore populations). Generally, offshore populations are larger, darker, and have proportionally shorter fins and beaks. Offshore populations can migrate up to in a season, but inshore populations tend to move less. However, some inshore populations make long migrations in response to
El Niño El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date ...
events. The species has occurred as far as 50° north in eastern Pacific waters, possibly as a result of warm water events. The coastal dolphins appear to adapt to warm, shallow waters. It has a smaller body and larger flippers, for maneuverability and heat dispersal. They can be found in harbors, bays, lagoons and estuaries. Offshore dolphins, however, are adapted to cooler, deeper waters. Certain qualities in their blood suggest they are more suited to deep diving. Their considerably larger body protects them against predators and helps them retain heat.


Other human interactions

Some interactions with humans are harmful to the dolphins. Dolphin hunting industry exists in multiple countries including Japan, where common bottlenose dolphins are hunted for food annually in the town of Taiji, and the Faroe Islands. Also, dolphins are sometimes killed inadvertently as a
bycatch Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...
of
tuna A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: ...
fishing. Tião was a well-known solitary male bottlenose dolphin that was first spotted in the town of São Sebastião in Brazil around 1994 and frequently allowed humans to interact with him. The dolphin later became infamous for killing a swimmer and injuring many others, which earned it the nickname of killer dolphin. Fungie is another solitary male bottlenose, living in close contact with humans in Dingle Harbour,
Ireland Ireland ( ; ga, Éire ; Ulster-Scots: ) is an island in the North Atlantic Ocean, in north-western Europe. It is separated from Great Britain to its east by the North Channel, the Irish Sea, and St George's Channel. Ireland is the s ...
, since 1983. He has become a symbol of the town, although some doubt exists over whether he is a single dolphin.


Conservation

The
North Sea The North Sea lies between Great Britain, Norway, Denmark, Germany, the Netherlands and Belgium. An epeiric sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian ...
,
Baltic Baltic may refer to: Peoples and languages *Baltic languages, a subfamily of Indo-European languages, including Lithuanian, Latvian and extinct Old Prussian *Balts (or Baltic peoples), ethnic groups speaking the Baltic languages and/or originatin ...
,
Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on ...
and
Black Sea The Black Sea is a marginal mediterranean sea of the Atlantic Ocean lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bounded by Bulgaria, Georgia, Rom ...
populations of the common bottlenose dolphin are listed in Appendix IIAppendix II
to the ''Convention on the Conservation of Migratory Species of Wild Animals'' (CMS). As amended by the Conference of the Parties to the Bonn Convention in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005, 2008, 2011 and 2014. Effective: 8 February 2015.
to the
Convention on the Conservation of Migratory Species of Wild Animals The Convention on the Conservation of Migratory Species of Wild Animals, also known as the Convention on Migratory Species (CMS) or the Bonn Convention, is an international agreement that aims to conserve migratory species throughout their r ...
(CMS) of the Bonn Convention, since they have an unfavorable conservation status or would benefit significantly from international cooperation organized by tailored agreements. The species is included in Appendix II of the
Convention on International Trade in Endangered Species CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of intern ...
(CITES), meaning international trade (including in parts/derivatives) is regulated. Estimated population of a few specific areas are including: The species is covered by the Agreement on Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas ( ASCOBANS), the Agreement on the Conservation of Cetaceans in the Black Sea, Mediterranean Sea and Contiguous Atlantic Area (
ACCOBAMS The Agreement on the Conservation of Cetaceans of the Black Sea, Mediterranean Sea and contiguous Atlantic Area, or ACCOBAMS, is a regional international treaty that binds its States Parties on the conservation of Cetacea in their territories. ...
), the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region, and the Memorandum of Understanding Concerning the Conservation of the Manatee and Small Cetaceans of Western Africa and Macaronesia.


Marine pollution

Common bottlenose dolphins are the most common apex predators found in coastal and estuarine ecosystems along the southern coast of the US, thus serve as an important indicator species of bioaccumulation and health of the ecosystem. It is believed that some diseases commonly found in dolphins are related to human behaviors, such as water pollution. Water pollution is linked to point and non-point source pollution. Point source pollution comes from a single source such as an oil spill and/or chemical discharge from a specific facility. The
environmental impact of the Deepwater Horizon oil spill The 2010 ''Deepwater Horizon'' oil spill in the Gulf of Mexico has been described as the worst environmental disaster in the United States, releasing about of crude oil making it the largest marine oil spill. Both the spill and the cleanup ef ...
caused a direct impact and still serves as a long-term impact of future populations. Common bottlenose dolphins use these important habitats for calving, foraging, and feeding. Environmental impacts or changes from chemicals or
marine pollution Marine pollution occurs when substances used or spread by humans, such as industrial, agricultural and residential waste, particles, noise, excess carbon dioxide or invasive organisms enter the ocean and cause harmful effects there. The major ...
can alter and disrupt endocrine systems, affecting future populations. For example, oil spills have been related to lung and reproductive diseases in female dolphins. A recent studysuggested signs of lung disease and impaired stress in 32 dolphins that were captured and assessed in Barataria Bay, Louisiana, US. Out of these 32 dolphins, 10 were found pregnant and, upon a 47-month check up, only 20% produced feasible calves, compared to a previous success rate of 83%, in the same area. It is believed that a recent oil spill in this area is partially to blame for these severely low numbers. Dense human development along the eastern coast of Florida and intense agricultural activity have resulted in increased freshwater inputs, changes in drainage patterns, and altered water quality (i.e. chemical contamination, high nutrient input, decreased salinity, decreased sea grass habitat, and eutrophication. High nutrient input from agriculture chemicals and fertilizers causes eutrophication and hypoxia, causing a severe reduction in water quality. Excess of phosphorus and nitrogen from these non-point sources deplete the natural cycle of oxygen by overconsumption of algae. Harmful algal blooms are responsible for dead zones and unusual mortality events of common bottlenose dolphins consuming these toxic fish from the brevetoxin produced by the dinoflagellate ''Karenia brevis''. Brevetoxins are neurotoxins that can cause acute respiratory and neurological symptoms, including death, in marine mammals, sea turtles, birds, and fishes.


See also

* List of cetaceans * Unihemispheric slow-wave sleep


References


External links

* * View th
dolphin genome
on
Ensembl Ensembl genome database project is a scientific project at the European Bioinformatics Institute, which provides a centralized resource for geneticists, molecular biologists and other researchers studying the genomes of our own species and other v ...
* * {{Taxonbar, from=Q174199 common bottlenose dolphin Tool-using mammals Cosmopolitan mammals Pantropical fauna common bottlenose dolphin Symbols of Mississippi