Difference between revisions of "Dolphins"

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#REDIRECT [[Dolphin]]
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{{otheruses}}
 
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{{Taxobox
 
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| color = pink
 
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| name = Dolphin
 
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| image = Bottlenose_Dolphin_KSC04pd0178.jpg
 
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| image_width = 250px
 
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| image_caption = [[Bottlenose Dolphin]] breaching in the bow wave of a boat
 
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| fossil_range = Early [[Miocene]] - Recent
 
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| regnum = [[Animal]]ia
 
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| phylum = [[Chordate|Chordata]]
 
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| classis = [[Mammal]]ia
 
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| ordo = [[Cetacea]]
 
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| subordo = [[Odontoceti]]
 
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| familia = '''Delphinidae''' and '''Platanistoidea'''
 
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| familia_authority = [[John Edward Gray|Gray]], 1821
 
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| subdivision_ranks = [[Genus|Genera]]
 
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| subdivision =
 
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See article below.
 
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}}
 
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'''Dolphins''' are [[aquatic mammal]]s which are closely related to [[whale]]s and [[porpoise]]s. There are almost forty species of dolphin in seventeen genera. They vary in size from 1.2 [[metre]]s (4 [[foot (unit of length)|ft]]) and 40 [[kilogram]]s (88 [[pound (unit of weight)|lb]]) ([[Maui's Dolphin]]), up to 9.5 m (30 ft) and ten [[tonne]]s (the [[Orca]]). They are found worldwide, mostly in the shallower seas of the [[continental shelves]], and are carnivores, mostly eating [[fish]] and [[squid]]. The [[Family (biology)|family]] Delphinidae is the largest in the Cetacea, and relatively recent: dolphins evolved about ten million years ago, during the [[Miocene]]. Dolphins are considered to be amongst the most intelligent of animals and their often friendly appearance and seemingly playful attitude have made them popular in [[human culture]].
 
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==Origin of the name==
 
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The name is from [[Ancient Greek]] {{polytonic|δελφίς}} ''delphis'' meaning "with a womb" which can be interpreted as meaning "a 'fish' with a womb".<ref>The American Heritage® Dictionary of the English Language, Fourth Edition, [http://dictionary.reference.com/browse/Dolphin online entry at Dictionary.com], retrieved [[December 17]] [[2006]].</ref>
 
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The word is used in a few different ways. It can mean:
 
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*Any member of the family [[Delphinidae]] (oceanic dolphins),
 
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*Any member of the families [[Delphinidae]] and [[Platanistoidea]] (oceanic and river dolphins),
 
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*Any member of the suborder [[Odontoceti]] (toothed whales; these include the above families and some others),
 
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*Used casually as a synonym for [[Bottlenose Dolphin]], the most common and familiar species of dolphin.
 
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In this article, the second definition is used. [[Porpoise]]s (suborder [[Odontoceti]], family [[Phocoenidae]]) are thus not dolphins in this sense. [[Orca]]s and some closely related species belong to the Delphinidae family and therefore qualify as dolphins, even though they are called whales in common language. A group of dolphins can be called a "school" or a "pod".
 
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==Taxonomy==
 
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[[Image:Comdolph.jpg|thumb|right|250px|Common Dolphin]]
 
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[[Image:Dolphintursiops.jpg|thumb|right|250px|Bottlenose Dolphin]]
 
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[[Image:Spotteddolphin1.jpg|thumb|right|250px|Spotted Dolphin]]
 
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[[Image:Commdolph01.jpg|thumb|250px|right|Commerson's Dolphin]]
 
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[[Image:Lagenorhynchus_obscurus.jpg|thumb|right|250px|Dusky Dolphin]]
 
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[[Image:Killerwhales jumping.jpg|thumb|right|250px|Killer Whales, also known as Orcas]]
 
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[[Image:Inia.jpg|thumb|right|250px|The Boto, or Amazon River Dolphin]]
 
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{{seealso|List of dolphins}}
 
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* [[Suborder]] [[Odontoceti]], toothed whales
 
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** [[Family (biology)|Family]] [[Delphinidae]], oceanic Dolphins
 
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*** [[Genus]] ''Delphinus''
 
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**** [[Long-Beaked Common Dolphin]], ''Delphinus capensis''
 
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**** [[Short-Beaked Common Dolphin]], ''Delphinus delphis''
 
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*** Genus ''Tursiops ''
 
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**** [[Bottlenose Dolphin]], ''Tursiops truncatus''
 
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**** [[Indo-Pacific Bottlenose Dolphin]], ''Tursiops aduncus''
 
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*** Genus ''Lissodelphis''
 
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**** [[Northern Rightwhale Dolphin]], ''Lissodelphis borealis''
 
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**** [[Southern Rightwhale Dolphin]], ''Lissiodelphis peronii''
 
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*** Genus ''Sotalia''
 
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**** [[Tucuxi]], ''Sotalia fluviatilis''
 
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*** Genus ''Sousa''
 
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**** [[Indo-Pacific Hump-backed Dolphin]], ''Sousa chinensis''
 
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***** [[Chinese White Dolphin]] (the Chinese variant), ''Sousa chinensis chinensis''
 
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**** [[Atlantic Humpbacked Dolphin]], ''Sousa teuszii''
 
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*** Genus ''Stenella''
 
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**** [[Atlantic Spotted Dolphin]], ''Stenella frontalis''
 
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**** [[Clymene Dolphin]], ''Stenella clymene''
 
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**** [[Pantropical Spotted Dolphin]], ''Stenella attenuata''
 
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**** [[Spinner Dolphin]], ''Stenella longirostris''
 
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**** [[Striped Dolphin]], ''Stenella coeruleoalba''
 
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*** Genus ''Steno''
 
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**** [[Rough-Toothed Dolphin]], ''Steno bredanensis''
 
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*** Genus ''Cephalorynchus''
 
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**** [[Chilean Dolphin]], ''Cephalorhynchus eutropia''
 
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**** [[Commerson's Dolphin]], ''Cephalorhynchus commersonii''
 
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**** [[Heaviside's Dolphin]], ''Cephalorhynchus heavisidii''
 
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**** [[Hector's Dolphin]], ''Cephalorhynchus hectori''
 
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*** Genus ''Grampus''
 
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**** [[Risso's Dolphin]], ''Grampus griseus''
 
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*** Genus ''Lagenodelphis''
 
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**** [[Fraser's Dolphin]], ''Lagenodelphis hosei''
 
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*** Genus ''Lagenorhyncus''
 
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**** [[Atlantic White-Sided Dolphin]], ''Lagenorhynchus acutus''
 
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**** [[Dusky Dolphin]], ''Lagenorhynchus obscurus''
 
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**** [[Hourglass Dolphin]], ''Lagenorhynchus cruciger''
 
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**** [[Pacific White-Sided Dolphin]], ''Lagenorhynchus obliquidens''
 
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**** [[Peale's Dolphin]], ''Lagenorhynchus australis''
 
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**** [[White-Beaked Dolphin]], ''Lagenorhynchus albirostris''
 
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*** Genus ''Orcaella''
 
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**** [[Australian Snubfin Dolphin]], ''Orcaella heinsohni''
 
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**** [[Irrawaddy Dolphin]], ''Orcaella brevirostris''
 
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*** Genus ''Peponocephala''
 
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**** [[Melon-headed Whale]], ''Peponocephala electra''
 
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*** Genus ''Orcinus''
 
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**** [[Killer Whale]], ''Orcinus orca''
 
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*** Genus ''Feresa''
 
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**** [[Pygmy Killer Whale]], ''Feresa attenuata''
 
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*** Genus ''Pseudorca''
 
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**** [[False Killer Whale]], ''Pseudorca crassidens''
 
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*** Genus ''Globicephala''
 
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**** Long-finned [[Pilot Whale]], ''Globicephala melas''
 
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**** Short-finned [[Pilot Whale]], ''Globicephala macrorhynchus''
 
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** Family [[Platanistoidea]], River Dolphins
 
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*** Genus ''Inia''
 
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**** [[Boto]] (Amazon River Dolphin), ''Inia geoffrensis''
 
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*** Genus ''Lipotes''
 
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**** [[Chinese River Dolphin]] (Baiji), ''Lipotes vexillifer''
 
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*** Genus ''Platanista''
 
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**** [[Ganges River Dolphin]], ''Platanista gangetica''
 
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**** [[Indus River Dolphin]], ''Platanista minor''
 
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*** Genus ''Pontoporia''
 
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**** [[La Plata Dolphin]] (Franciscana), ''Pontoporia blainvillei''
 
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Six species in the family Delphinidae are commonly called "whales" but are strictly speaking dolphins. They are sometimes called "blackfish".
 
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* [[Melon-headed Whale]], ''Peponocephala electra''
 
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* [[Orca|Killer Whale]], ''Orcinus orca''
 
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* [[Pygmy Killer Whale]], ''Feresa attenuata''
 
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* [[False Killer Whale]], ''Psudorca crassidens''
 
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* Long-finned [[Pilot Whale]], ''Globicephala melas''
 
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* Short-finned [[Pilot Whale]], ''Globicephala macrorhynchus''
 
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===Hybrid dolphins===
 
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In [[1933]], three abnormal dolphins were beached off the [[Ireland|Irish]] coast; these appeared to be hybrids between Risso's Dolphin and the Bottlenose Dolphin.<ref>Dolphin Safari (2006) [http://www.dolphinsafari.com/sightingslog.html sightings log], page retrieved [[December 17]] [[2006]].</ref> This mating has since been repeated in captivity and a hybrid calf was born. In captivity, a Bottlenose Dolphin and a Rough-toothed Dolphin produced hybrid offspring.<ref>Texas Tech University (1997), [http://www.nsrl.ttu.edu/tmot1/stenbred.htm Mammals of Texas - Rough-toothed Dolphin], article retrieved [[December 8]] [[2006]].</ref> A Common-Bottlenose hybrid lives at [[SeaWorld]] California.<ref>Robin's Island [http://www.robins-island.org/dolphins_database.php?filter=Sea_World_California Dolphins at SeaWorld California], page retrieved [[December 17]] [[2006]].</ref> Various other dolphin hybrids have also been reported in the wild, such as a Bottlenose-Atlantic Spotted hybrid.<ref>Denise L. Herzing, Kelly Moewe and Barbara J. Brunnick (2003), [http://www.trustedpartner.com/docs/library/000059/Herzing%20Moewe%20Brunnick%20final.pdf Interspecies interactions between Atlantic spotted dolphins, Stenella frontalis and bottlenose dolphins, Tursiops truncatus, on Great Bahama Bank, Bahamas], article retrieved on [[December 17]] [[2006]].</ref> The best known hybrid however is the [[Wolphin]], a False Killer Whale-Bottlenose Dolphin hybrid. The Wolphin is a fertile hybrid, and two such Wolphins currently live at the Sea Life Park in [[Hawaii]], the first having been born in 1985 from a male False Killer Whale and a female Bottlenose.
 
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==Evolution and anatomy==
 
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[[Image:Dolphin_anatomy.png|thumb|360px|right|The Anatomy of a Dolphin showing its skeleton, major organs and body shape.]]
 
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===Evolution===
 
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{{seealso|Evolution of cetaceans}}
 
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Dolphins, along with whales and porpoises, are thought to be descendants of terrestrial mammals, most likely of the [[Artiodactyl]] [[order (biology)|order]]. The ancestors of the modern day dolphins entered the water roughly fifty million years ago. Though this is probably false as the bible contradicts such claims.
 
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[[Image:Dolphin_embryo.jpg|thumb|left|'''Hind Limb Buds on Dolphins''' An embryo of a Spotted Dolphin in the fifth week of development. The hind limbs are present as small bumps (hind limb buds) near the base of the tail. The pin is approximately 1 inch (~2,5 cm) long.]]
 
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[[Image:Bottlenose_dolphin_hind.jpg|thumb|left|Bottlenose Dolphin with vestigial hind flippers, captured 2006 in Japan.]]
 
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Modern dolphin skeletons have two small, rod-shaped pelvic bones thought to be [[vestigial]] hind legs.  In [[October 2006]] an unusual Bottlenose Dolphin was captured in Japan; it had small fins on each side of its genital slit which scientists believe to be a more pronounced development of these vestigal hind legs.<ref>[[Associated Press]] / [[FOX news]] (2006), [http://www.foxnews.com/story/0,2933,227572,00.html Japanese Researchers Find Dolphin With 'Remains of Legs'], article retrieved [[November 6]] [[2006]].</ref>
 
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===Anatomy===
 
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Dolphins have a streamlined [[fusiform]] body, adapted for fast swimming.  The basic colouration patterns are shades of grey with a light underside and a distinct dark cape on the back. It is often combined with lines and patches of different hue and contrast.
 
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The head contains the [[melon (whale)|melon]], a round organ used for [[animal echolocation|echolocation]]. In many species, the jaws are elongated, forming a distinct beak; for some species like the Bottlenose, there is a curved mouth which looks like a fixed smile.  Teeth can be very numerous (up to two hundred and fifty) in several species. The [[dolphin brain]] is large and has a highly structured cortex, which often is referred to in discussions about their advanced intelligence. 
 
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Unlike most mammals, dolphins do not have hair, but they are born with a few hairs around the tip of their [[rostrum]] which they lose after some time, in some cases even before they are born. The only exception to this is the [[Boto]] river dolphin, which does have some small hairs on the rostrum.
 
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===Senses===
 
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Most dolphins have acute [[eyesight]], both in and out of the water, and their sense of [[Hearing (sense)|hearing]] is superior to that of humans. Though they have a small ear opening on each side of their head, it is believed that hearing underwater is also if not exclusively done with the lower jaw which conducts the sound vibrations to the [[middle ear]] via a fat-filled cavity in the lower jaw bone. Hearing is also used for echolocation, which seems to be an ability all dolphins have. Their teeth are arranged in a way that works as an array or antenna to receive the incoming sound and make it easier for them to pinpoint the exact location of an object.<ref>Goodson, A.D. and M. Klinowska. "A Proposed Echolocation Receptor for the Bottlenose Dolphin (''Tursiops truncatus''): Modelling the Receive Directivity from Tooth and Lower Jaw Geometry", in Thomas and Kastelein, eds, ''NATO ASI Series A: Sensory Abilities of Cetaceans'', vi.196:255-267 (Plenum NY, 1990) ISBN 0-30-643695-7</ref> The dolphin's sense of touch is also well-developed.  However, dolphins lack an olfactory nerve and lobes and thus are believed to have no [[sense of smell]],<ref>SeaWorld, [http://www.seaworld.org/animal-info/info-books/bottlenose/senses.htm Bottlenose Dolphins - Senses], article retrieved [[December 17]] [[2006]].</ref> but they can [[taste]] and do show preferences for certain kinds of fish. Since dolphins spend most of their time below the surface normally, just tasting the water could act in a manner analogous to a sense of smell.
 
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Though most dolphins do not have any hair, they do still have [[hair follicle]]s and it is believed these might still perform some sensory function, though it is unclear what exactly this may be.<ref>Bjorn Mauck, Ulf Eysel and Guide Dehnhardt (2000), [http://jeb.biologists.org/cgi/reprint/203/14/2125.pdf Selective heating of vibrissal follicles in seals (Phoca Vitulina) and dolphins (Sotalia Fluviatilis Guianensis)], article retrieved [[March 11]], 2007.</ref> The small hairs on the rostrum of the Boto river dolphin are believed to function as a [[touch|tacticle sense]] however, possibly to compensate for the Boto's poor eyesight.<ref>Laurie Stepanek (1998), [http://www.tmmsn.org/mmgulf/inia_geoffrensis.html Amazon River Dolphin (Inia geoffrensis)], article retrieved [[March 11]], 2007.</ref>
 
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==Behaviour==
 
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{{Seealso|Whale behaviour}}
 
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[[Image:Duskydolphin17.jpg|right|thumb|250px|[[Pacific White-Sided Dolphin]]s breaching]]
 
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Dolphins are often regarded as one of Earth's most intelligent animals, though it is hard to say just how intelligent dolphins are, as comparisons of species' relative intelligence are complicated by differences in sensory apparatus, response modes, and nature of cognition. Furthermore, the difficulty and expense of doing experimental work with large aquatics means that some tests which could meaningfully be done still have not been carried out, or have been carried out with inadequate sample size and methodology. Dolphin behaviour has been studied extensively by humans however, both in captivity and in the wild. See the [[cetacean intelligence]] article for more details.
 
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===Social behaviour===
 
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They are also willing to occasionally approach humans and playfully interact with them in the water. In return, some human cultures such as the [[Ancient Greece|Ancient Greeks]] treated them with welcome; a ship spotting dolphins riding in their wake was considered a good omen for a smooth voyage. There are stories of dolphins protecting swimmers against sharks by swimming circles around them.<ref>CBC News (2004), [http://www.cbc.ca/world/story/2004/11/24/dolphin_newzealand041124.html Dolphins save swimmers from shark], article retrieved [[March 11]], 2007.</ref>
 
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[[Image:Dolphins-surfing.jpg|left|thumb|250px|Dolphins surfing at [[Snapper Rocks]], [[Queensland]], [[Australia]].]]
 
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Dolphins are social, living in pods (also called "schools") of up to a dozen individuals. In places with a high abundance of food, pods can join temporarily, forming an aggregation called a '''superpod'''; such groupings may exceed a thousand dolphins. The individuals communicate using a variety of clicks, whistles and other vocalizations. They also use ultrasonic sounds for [[animal echolocation|echolocation]]. Membership in pods is not rigid; interchange is common. However, the cetaceans can establish strong bonds between each other. This leads to them staying with injured or ill individuals for support.
 
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In May 2005, researchers in [[Australia]] discovered a cultural aspect of dolphin behaviour: Some dolphins (''Tursiops aduncus'') teach their children to use tools. The dolphins break [[sea sponge|sponge]]s off and cover their snouts with them thus protecting their snouts while foraging. This knowledge of how to use a tool is mostly transferred from mothers to daughters, unlike [[simian]] [[primate]]s, where the knowledge is generally passed on to both sexes. The technology to use sponges as mouth protection is not genetically inherited but a taught behaviour.<ref>Rowan Hooper for New Scientist (2005), [http://www.newscientist.com/article.ns?id=dn7475 Dolphins teach their children to use sponges], article retrieved [[December 17]] [[2006]].</ref>
 
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Dolphins are one of the few animals other than humans known to mate for reasons other than reproduction. Male Bottlenose Dolphins are known to engage in sexual acts with other dolphin species, which is not always consensual, though the Bottlenose may also be submissive in such encounters.<ref>National Geographic's ''Dolphins: The wild side'' documentary (1999), [http://www.imdb.com/title/tt0386415/ IMDb entry] / [http://www.nationalgeographic.com/tv/press/990202.html National Geographic website entry]</ref> Occasionally, dolphins will also show sexual behaviour towards humans.<ref>Amy Samuels, Lars Bejder, Rochelle Constantine and Sonja Heinrich (2003),  [http://whitelab.biology.dal.ca/lb/Samuels%20Bejder%20et%20al%202003.pdf Marine Mammals: Fisheries, Tourism and Management Issues, chapter 15], pages 266 to 268, Cetaceans that are typically lonely and seek human company. Retrieved [[December 17]] [[2006]].</ref>
 
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Dolphins are known to engage in acts of aggression towards each other. The older a male dolphin is, the more likely his body is covered with scars ranging in depth from teeth marks made by other dolphins. It is suggested that male dolphins engage in such acts of aggression for the same reasons as humans: disputes between companions or even competition for other females. Acts of aggression can become so intense that targeted dolphins are known to go into exile, leaving their communities as a result of losing a fight with other dolphins.
 
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Male Bottlenose Dolphins have been known to engage in [[infanticide]]. Dolphins have also been known to kill [[porpoises]] for reasons which are not fully understood, as porpoises generally do not share the same fish diet as dolphins and are therefore not competitors for food supplies.<ref>Dr. George Johnson (date unknown), [http://www.txtwriter.com/Onscience/Articles/Flipper.html Is Flipper A Senseless Killer?], article retreived [[December 17]] [[2006]].</ref>
 
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===Feeding===
 
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[[Image:OrcaSeal.jpg|thumb|right|250px|Orca grabbing a seal from the beach in [[Patagonia]] ]]
 
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Individual species may employ a number of methods of hunting. One such method is herding, where a superpod will control a school of fish while individual members take turns plowing through the herd, feeding. The tightly packed school of fish is commonly known as bait ball. Coralling is a method where fish are chased to shallow water where they are more easily captured. In [[South Carolina]], the Atlantic [[Bottlenose Dolphin]] takes this one step further with what has become known as strand feeding, where the fish are driven onto mud banks and retrieved from there.<ref>[http://www.nmfs.noaa.gov/pr/pdfs/species/coastalbottlenosestock.pdf "Coastal Stock(s) of Atlantic Bottlenose Dolphin: Status Review and Management,"] Proceedings and Recommendations from a Workshop held in Beaufort, North Carolina, 13-14 September 1993. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service. pp. 56-57.</ref> In some places, Orcas will also come up to the beach to capture [[Pinniped|seals]]. Some species also whack fish with their fluke, stunning them and sometimes sending fish clear out of the water.
 
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Reports of cooperative human-dolphin fisheries date back to [[Pliny the Elder|Pliny]]. A modern human-dolphin fishery still takes place in [[Laguna, Brazil|Laguna]], [[Santa Catarina (state)|Santa Catarina]], [[Brazil]].<ref>The Telegraph (2006), [http://www.telegraph.co.uk/travel/main.jhtml?xml=/travel/2006/03/09/etbrazil09.xml&page=1 Brazil's sexiest secret], article retrieved [[March 11]], 2007.</ref>
 
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===Jumping and playing===
 
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Dolphins often leap above the water surface, sometimes performing acrobatic figures (e.g. the [[spinner dolphin]]). Scientists are not always quite certain about the purpose of this behaviour and the reason for it may vary, it could be to locate schools of fish by looking at above-water signs like feeding birds, they could be communicating to other dolphins to join a hunt, attempting to dislodge parasites, or simply doing it for fun. Play is a very important part of dolphins' lives, and they can often be observed playing with seaweed or play-fighting with other dolphins. They even harass other locals, like seabirds and turtles. Dolphins also seem to enjoy riding waves and frequently 'surf' coastal swells and the bow waves of boats. 
 
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==Human-dolphin relationships==
 
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===Mythology===
 
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{{seealso|Dolphins in mythology}}
 
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Dolphins have long played a role in human culture. Dolphins are common in [[Greek mythology]] and there are many coins from the time which feature a man or boy riding on the back of a dolphin. Dolphins also seem to have been important to the [[Minoans]], judging by artistic evidence from the ruined palace at [[Knossos]]. In [[Hindu mythology]], the Ganges River Dolphin is associated with [[Ganga]], the deity of the [[Ganges]] river.
 
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===Entertainment===
 
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[[Image:Keiko-weighing.jpg|thumb|right|150px|The famous Orca Keiko from the Free Willy movies being prepared for transport.]]
 
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In more recent times, the [[Flipper (1963 film)|1963 ''Flipper'' movie]] and the subsequent popular ''[[Flipper (1964 TV series)|Flipper television series]]'', contributed to the popularity of dolphins in [[Western World|Western society]]. The series, created by [[Ivan Tors]], portrayed a dolphin in a friendly relationship with two boys, Sandy and Bud; a kind of seagoing ''[[Lassie (1954 TV series)|Lassie]]''. Flipper, a Bottlenose Dolphin, understood English unusually well and was a marked hero. A [[Flipper (1996 film)|second ''Flipper'' movie]] was made in [[1996]], which was based on the story of the original movie. A Bottlenose Dolphin also played a prominent role in the 1990s [[science fiction television]] series ''[[seaQuest DSV]]'' in which the animal, named Darwin, could communicate with English speakers using a vocoder, a fictional invention which translated the clicks and whistles to English and back.
 
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[[Image:OceanWorld_DolphinPhoto.jpg|left|thumb|220px|A young couple being entertained by a trained Bottlenose Dolphin in [[Puerto Plata]], [[Dominican republic]].]] More well known from this time period is probably the movie ''[[Free Willy]]'' however, which made famous the Orca playing Willy, [[Keiko (orca)|Keiko]]. The [[1977]] [[horror movie]] ''[[Orca (film)|Orca]]'' paints a less friendly picture of the animal. Here, a male Orca takes revenge on fishermen after the killing of his mate. The [[1973]] movie ''[[The Day of the Dolphin]]'' also has a dark role for dolphins, which are trained to perform an [[assassination]].
 
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The renewed popularity of dolphins in the 1960s resulted in the appearance of many [[dolphinarium]]s around the world, which have made dolphins accessible to the public. Though criticism and more strict [[animal welfare]] laws have forced many dolphinariums to close their doors, hundreds still exist around the world attracting large amount of visitors. In the [[United States]], best known are the [[SeaWorld]] [[marine mammal park]]s, and their common Orca stage name ''[[Shamu]]'', which they have trademarked, has become well known. [[Southwest Airlines]], an American airline, has even painted three of their [[Boeing 737]] aircraft in ''Shamu'' colours as an advertisement for the parks and have been flying with such a livery on various aircraft since [[1988]].
 
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Occasionally, dolphins make an appearance in [[computer games]]. Best known is the ''[[Ecco the Dolphin]]'' game series. The games are named after their main character, Ecco, a young Bottlenose Dolphin. The Ecco the Dolphin games hinge on the idea that cetaceans are sapient beings and have their own underwater society.
 
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A well known American [[National Football League]] (NFL) team is named the [[Miami Dolphins]]. Their logo depicts an aqua-coloured Bottlenose Dolphin wearing an [[American football]] helmet and jumping in front of a coral-coloured sunburst.
 
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===Military===
 
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A number of militaries have employed dolphins for various purposes from finding mines to rescuing lost or trapped humans. Such [[military dolphins]], however, drew scrutiny during the Vietnam War when rumors circulated that dolphins were being trained to kill Vietnamese [[Skin diving|skin divers]]. Best known today is the [[U.S. Navy Marine Mammal Program]].
 
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===Literature===
 
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Dolphins are also common in contemporary literature, especially [[science fiction novel]]s. A military role for dolphins is found in [[William Gibson (novelist)|William Gibson]]'s short story ''[[Johnny Mnemonic]]'', in which [[cyborg]] dolphins are used in war-time by the military to find submarines and, after the war, by a group of revolutionaries to decode encrypted information. More humorous is ''[[The Hitchhiker's Guide to the Galaxy]]'', in which dolphins are the second most intelligent creatures on Earth, after mice, and tried in vain to warn humans of the impending destruction of the planet. However, their behaviour was misinterpreted as playful [[acrobatics]]. Their story is told in ''[[So Long, and Thanks for All the Fish]]''. Much more serious is their major role (along with [[chimpanzee]]s) in [[David Brin]]'s [[Uplift Universe|Uplift]] series.
 
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Dolphins also appear frequently in non-science fiction literature however. In the book ''The Music of dolphins'' by author [[Karen Hesse]], a girl is raised by dolphins from the age of four until she is discovered by the [[coast guard]]. Fantasy author [[Ken Grimwood]] wrote dolphins into his [[1995]] novel ''Into the Deep'' about a [[marine biology|marine biologist]] struggling to crack the code of [[cetacean intelligence|dolphin intelligence]], including entire chapters written from the viewpoint of his dolphin characters. In this book, humans and dolphins are capable of communicating via [[telepathy]].
 
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==Human threats to dolphins==
 
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[[Image:Whaling in the Faroe Islands.jpg|thumb|right|250px|Dead Atlantic White-Sided Dolphins in [[Hvalba]] on the [[Faroe Islands]], killed in a drive hunt. ]]
 
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Some dolphin species face an uncertain future, especially some of the river dolphin species such as the Amazon River dolphin, and the Ganges and Yangtze River dolphin, all of which are critically or seriously endangered. A 2006 survey found no individuals of the Yangtze River dolphin, leading to the conclusion that the species is now [[functionally extinct]].<ref>Douglas Williams for Shanghai Daily (2006), [http://www.shanghaidaily.com/art/2006/12/04/298862/Yangtze_dolphin_may_be_extinct__researchers_say.htm Yangtze dolphin may be extinct]. Article retrieved [[December 9]] [[2006]].</ref>
 
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Contamination of environment - the oceans, seas, and rivers - is an issue of concern, especially [[pesticides]], heavy metals, plastics, and other industrial and agricultural pollutants which do not disintegrate rapidly in the environment are reducing dolphin populations, and resulting in dolphins building up unusually high levels of contaminants. Injuries or deaths due to collisions with boats, especially their [[propeller]]s, are also common.
 
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Various fishing methods, most notably [[Seine (fishing)|purse seine]] fishing for [[tuna]] and the use of drift and gill nets, results in a large amounts of dolphins being killed inadvertently.<ref>Clover, Charles. 2004. ''The End of the Line: How overfishing is changing the world and what we eat''. Ebury Press, London. ISBN 0-09-189780-7 </ref> Accidental by-catch in [[trout]] nets is common and poses a risk for mainly local dolphin populations. In some parts of the world, such as some areas in [[Japan]] and the [[Faroe Islands]], dolphins are traditionally considered as food, and killed in [[harpoon]] or [[dolphin drive hunting|drive hunts]].
 
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==== 2007: Year of the Dolphin ====
 
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The year [[2007]] has been declared as [[(International) Year of the Dolphin]] by the [[United Nations]] and [[United Nations Environment Programme]] ([[UNEP]]).<ref>[http://www.yod2007.org 2007: (International) Year of the Dolphin - Official website], website retrieved on January 14, 2007.</ref> The idea was launched by the UN's [[Convention on Migratory Species]] and the [[Whale and Dolphin Conservation Society]] (WDCS).
 
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==References==
 
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{{reflist}}
 
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==External links==
 
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{{Commons|Dolphin}}
 
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{{wikispecies|Delphinidae}}
 
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{{cetaceaportal}}
 
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'''Further information:'''
 
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*[http://www.omplace.com/omsites/discover/DOLPHINS/ OM Place - pictorial comparative chart of various dolphin species.]
 
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*[http://www.ancientspiral.com/dolphin1.htm Dolphins and their significance in world mythology.]
 
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*[http://www.harmlesslion.com/dolphins/index.htm Tursi's dolphin page]
 
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'''Dolphin conservation and research:'''
 
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*[http://www.wdcs.org The Whale & Dolphin Conservation Society (WDCS)]
 
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*[http://charityguide.org/volunteer/vacation/bottlenose-dolphins.htm Charityguide.com - Save Bottlenose dolphins]
 
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*[http://www.dolphin-institute.org/ The Dolphin Institute]
 
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*[http://www.dolphins.org/ The Dolphin research center]
 
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*[http://www.neoucom.edu/DLDD/ Digital Library of Dolphin Development], Cetacean origins, Thewissen Lab
 
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'''Dolphin news:'''
 
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*[http://www.tursiops.org/ Tursiops.org: Current Cetacean-related news]
 
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'''Dolphin photos:'''
 
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*[http://www.robertosozzani.it/Delfini/cont.html Red Sea Spinner Dolphin - Photo gallery]
 
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*[http://www.pbs.org/wnet/nature/dolphins/index.html PBS NOVA: Dolphins: Close Encounters]
 
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*[http://neptune.atlantis-intl.com/dolphins/preview_root.html David's Dolphin Images]
 
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*[http://www.terranomada.com/dolphins/dolphins.html Images of Wild Dolphins in the Red Sea]
 
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*[http://www.nationalgeographic.com/kids/creature_feature/0108/dolphins.html National Geographic]
 
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[[Category:Toothed whales]]
 

Latest revision as of 18:35, April 12, 2007

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