Ajay Kumar at 05:24, 29 August 2023

2023-08-29T05:24:23Z

New page

{{Short description|Species of toothed whale}}
{{Speciesbox
| fossil_range = {{Fossil range|0.012|0}}Early [[Holocene]] – present<ref name="fossilworks" />
| name = Ganges river dolphin
| status = EN
| status_system = IUCN3.1
| status_ref = <ref name="iucn">{{cite iucn |title=''Platanista gangetica'' |author1=Kelkar, N.|author2=Smith, B.D.|author3=Alom, M.Z.|author4=Dey, S.|author5=Paudel, S.|author6=Braulik, G.T. |date=2022 |page=e.T41756A50383346 |doi=10.2305/IUCN.UK.2022-1.RLTS.T41756A50383346.en |access-date=17 October 2022}}</ref>
| status2 = CITES_A1
| status2_system = CITES
| status2_ref = <ref name="Appendices {{!}} CITES">{{Cite web |title=Appendices {{!}} CITES |url=https://cites.org/eng/app/appendices.php |access-date=2022-01-14 |website=cites.org}}</ref>
| image = The magnificent Ganges River Dolphin.jpg
| genus = Platanista
| species = gangetica
| authority = ([[Heinrich Julius Lebeck|Lebeck]], 1801)
| range_map = SouthAsianRiverDolphin distribution2019.png
| range_map_caption = Ranges of the <span style="color:#0202fd;">Indus river dolphin</span> and <span style="color:#f2790e;">Ganges river dolphin</span>
| synonyms = ''Platanista gangetica gangetica''
| image2 = Ganges and Indus river dolphin size.svg
}}

The '''Ganges river dolphin''' ('''''Platanista gangetica''''') is a species of [[toothed whale]] classified in the family [[Platanistidae]]. It lives in the [[Ganges]] and related rivers of [[South Asia]], namely in the countries of [[India]], [[Nepal]], and [[Bangladesh]].<ref name="WWF">{{Cite web |last=WWF |title=WFF Ganges river Dolphin |url=https://www.worldwildlife.org/species/ganges-river-dolphin |website=WFF Conservation}}</ref> It is related to the much smaller [[Indus river dolphin]] which lives in the [[Indus River]] in [[Pakistan]] and the [[Beas River]] of northwestern India.<ref>{{Cite web |title=Signs of hope as population of endangered Indus River dolphin jumps in Pakistan |url=http://wwf.panda.org/?318636/Signs-of-hope-as-population-of-endangered-Indus-River-dolphin-jumps-in-Pakistan&utm_ |access-date=2017-12-17 |publisher=WWF}}</ref>

It is also known by the name '''''susu''''' (popular name) or "Sisu" (Assamese language) and '''''shushuk''''' ([[Bengali language|Bengali]]).<ref name="NBK">{{cite-NBK|Susu, the blind purpoise ... in the Ganges River, blind porpoise of Asia}}, page 451 [letter A] and page 568 [letter S].</ref> The Ganges river dolphin has been recognized by the [[Government of India]] as its [[List of national animals|National Aquatic Animal]]<ref>{{Cite web |date=10 May 2010 |title=Declaration of Gangetic Dolphin as National Aquatic Animal |url=http://www.moef.nic.in/sites/default/files/dolphin-eng_0.pdf |access-date=23 October 2016 |website=Government of India – Ministry of Environment, Forest and Climate Change}}</ref> and is the official animal of the Indian city of [[Guwahati]].<ref>{{Cite news |date=6 June 2016 |title=Gangetic river dolphin to be city animal of Guwahati |work=The Times of India |url=http://timesofindia.com/home/environment/flora-fauna/Gangetic-river-dolphin-to-be-city-animal-of-Guwahati/articleshow/52623206.cms}}</ref> Its first occurrence, within the [[Hooghly River]], was documented by [[William Roxburgh]].<ref>{{Cite journal |last=Sinha K. |first=Ravindra |date=2014 |title=Ganges River Dolphin: An Overview of Biology, Ecology, and Conservation Status in India |journal=[[Journal of Biology]] |volume=43 |issue=8 |pages=1029–1046 |doi=10.1007/s13280-014-0534-7 |pmc=4235892 |pmid=24924188}}</ref>
[[File:Ganges river dolphin skeleton.jpg|thumb|Ganges river dolphin skeleton specimen exhibited in [[Pisa Charterhouse|Museo di storia naturale e del territorio dell'Università di Pisa]]]]

== Taxonomy ==
The Ganges river dolphin split from the [[Indus river dolphin]] during the [[Pleistocene]], around 550,000 years ago.<ref name="fossilworks">{{Cite web |title=Fossilworks: Platanista gangetica |url=http://www.fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=63565}}</ref> The earliest fossil identified as belonging to the species is only 12,000 years old.<ref>{{Cite web |title=Fossilworks: Platanista gangetica |url=http://www.fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=63565 |access-date=2021-08-27 |website=fossilworks.org}}</ref>

The Ganges river dolphin was formally classified as ''Delphinus gangeticus'' two separate times in 1801, by [[Heinrich Julius Lebeck]]<ref>{{Cite journal |last=Lebeck, H. J. |year=1801 |title=Delphinus gangeticus beschrieben vom Herrn Heinrich Julius Lebeck zu Trankenbar. |url=https://archive.org/details/bub_gb_eOgTAAAAQAAJ/page/280/mode/1up |journal=Neue SCHR. Ges. Naturf. Fr. Berl. |volume=3 |pages=280–282}}</ref> and [[William Roxburgh]]. They both likely used the [[type specimen]], caught near [[Calcutta]] in late 1797 and sent to the [[Hunterian Museum (London)|Hunterian Museum]] in London. It may have been destroyed during World War II, but castings were previously made of the rostrum and parts of the lower jaw, which survive at the [[Natural History Museum, London|Natural History Museum]].<ref name="Braulik_al20212" /> Whether Lebeck or Roxburgh should be given credit has been debated over the centuries, but research by Kinze (2000) found that Lebeck's description was published on the 24 August while Roxburgh's was likely published no earlier than September, thus giving Lebeck the [[Principle of priority|priority]].<ref name="Braulik_al20212" /><ref>{{Cite journal |last=Kinze |first=C. C. |year=2000 |title=Rehabilitation of ''Platanista gangetica'' (Lebeck, 1801) as the valid scientific name of the Ganges dolphin |journal=Zoologische Mededelingen |volume=74 |issue=11 |pages=193–203 |issn=0024-0672}}</ref> [[Elisha Gray]] coined the species name '' Platanista gangetica'' in 1835.<ref name="Braulik_al20212" />

This species and the Indus river dolphin, were initially classified as a single species, ''Platanista gangetica'', but in the 1970s both were split into distinct species. However, in the 1990s, both species were again grouped as a single species. However, more recent studies of genes, divergence time, and skull structure support both being distinct species.<ref>{{Cite web |title=Explore the Database |url=https://www.mammaldiversity.org/explore.html#species-id=1006462 |access-date=2021-08-27 |website=www.mammaldiversity.org}}</ref><ref name="Braulik_al20212">{{Cite journal |last=Braulik |first=G. T. |last2=Archer |first2=F. I. |last3=Khan |first3=U. |last4=Imran |first4=M. |last5=Sinha |first5=R. K. |last6=Jefferson |first6=T. A. |last7=Donovan |first7=C. |last8=Graves |first8=J. A. |year=2021 |title=Taxonomic revision of the South Asian River dolphins (''Platanista''): Indus and Ganges River dolphins are separate species |journal=Marine Mammal Science |volume=37 |issue=3 |pages=1022–1059 |doi=10.1111/mms.12801 |doi-access=free}}</ref>

=== Etymology ===
The species has multiple common names throughout its range. It is known as '''''susu''''' as a popular name; '''''soons''''', '''''soans''''', or '''''soos''''' in [[Hindi]]; '''''shushuk''''' in [[Bengali language|Bengali]]; '''''hiho''''' or '''''hihu''''' in [[Assamese language|Assamese]]; '''''bhagirath''''' (as a reference to the [[Bhagiratha|character of the same name]] from [[Hindu mythology]]); and '''''shus''''' or '''''suongsu''''' in [[Nepali language|Nepali]]. Its [[Sanskrit]] name in [[Medieval India|medieval]] times was likely '''''shishumar''''', and during the [[Mughal Empire|Mughal era]], it was known as '''''pani suar'''''.<ref name="Braulik_al20212" />
[[File:South Asian river dolphin© Md Sharif Hossain Sourav.jpg|thumb|In [[Sundarbans]], Bangladesh]]

== Distribution ==
It lives along the Ganges-Brahmaputra-Meghna and Karnaphuli-Sangu river systems of Bangladesh and India, and the Sapta Koshi and Karnali Rivers in Nepal.<ref name="EDGE">{{Cite web |title=South Asian river dolphin (''Platanista gangetica'') |url=http://www.edgeofexistence.org/mammals/species_info.php?id=65 |url-status=dead |archive-url=https://web.archive.org/web/20111013075943/http://edgeofexistence.org/mammals/species_info.php?id=65 |archive-date=13 October 2011 |access-date=26 July 2011 |publisher=EDGE}}</ref><ref name="Paudel 59–68">{{Cite journal |last=Paudel |first=S. |last2=Pal |first2=P. |last3=Cove |first3=M.V. |last4=Jnawali |first4=S.R. |last5=Abel |first5=G. |last6=Koprowski |first6=J.L. |last7=Ranabhat |first7=R. |year=2015 |title=The Endangered Ganges River dolphin ''Platanista gangetica gangetica'' in Nepal: abundance, habitat and conservation threats |journal=Endangered Species Research |volume=29 |issue=1 |pages=59–68 |doi=10.3354/esr00702 |doi-access=free}}</ref> The Ganges river dolphin favours deep pools, eddy countercurrents located downstream of the convergence of rivers and of sharp meanders, and upstream and downstream of midchannel islands.<ref name="Paudel 59–68" /><ref name=":2">{{Cite web |title=Ganges River dolphin |url=http://wwf.panda.org/knowledge_hub/endangered_species/cetaceans/about/river_dolphins/ganges_river_dolphin/ |access-date=25 August 2019 |publisher=WWF}}</ref>

== Description ==
The Ganges river dolphin has a rectangular, ridgelike dorsal fin and females tend to be larger than males.<ref name="whales" /> Ganges river dolphins usually are tan, chocolate brown, dark grey or light blue. They have an elongated, slender snout with sharp and very pointed teeth, similar to most river dolphins. The river dolphin has a rounded belly which, combined with their rectangular dorsal fin, makes them look particularly stocky in build compared to other dolphins. Their flippers and tail flukes are large and broad.<ref name="WDC">{{Cite web |title=South Asian River Dolphin |url=https://us.whales.org/whales-dolphins/species-guide/south-asian-river-dolphin/ |access-date=March 6, 2022 |website=Whale and Dolphin Conservation}}</ref> They have a large melon head used for [[animal echolocation|echolocation]], because they cannot see well. Their eyes are usually small due to the cloudy water.<ref name="whales" /> Ganges river dolphins are usually 2.2-2.6 meters long (7–8 ft). The oldest recorded animal was a 28-year-old male, 199 cm in length, although they are estimated to live up to 30 years old.<ref name="WDC" /><ref>{{Cite journal |last=Kasuya, T. |year=1972 |title=Some information on the growth of the Ganges dolphin with a comment on the Indus dolphin |url=https://www.icrwhale.org/pdf/SC02487-108.pdf |journal=Sci. Rep. Whales Res. Inst. |volume=24 |pages=87–108}}</ref>

== Behavior ==

The Ganges river dolphins usually swim alone or in pairs and are not known to do acrobatic maneuvers near boats.<ref name="whales">{{Cite web |title=South Asian river dolphin |url=http://us.whales.org/species-guide/south-asian-river-dolphin |access-date=18 April 2018 |website=[[Whale and Dolphin Conservation Society]]}}</ref> Little is known about their behavior because they are usually shy around boats and are hard to observe.<ref name="whales" /> They are known to breach; however this is rare.<ref name="whales" />

=== Vocalization ===
This species shows object-avoidance behavior in both the consistently heavily murky waters of its habitat and in clear water in captivity, suggesting it is capable of using echolocation effectively to navigate and forage for prey.<ref name=":0">{{Cite journal |last=Herald |first=Earl S. |last2=Brownell |first2=Robert L. |last3=Frye |first3=Fredric L. |last4=Morris |first4=Elkan J. |last5=Evans |first5=William E. |last6=Scott |first6=Alan B. |year=1969 |title=Blind River Dolphin: First Side-Swimming Cetacean |url=https://digitalcommons.unl.edu/usdeptcommercepub/138 |journal=Science |volume=166 |issue=3911 |pages=1408–1410 |bibcode=1969Sci...166.1408H |doi=10.1126/science.166.3911.1408 |jstor=1727285 |pmid=5350341 |s2cid=5670792}}</ref> Information is limited on how extensively vocalization is used between individuals. It is capable of performing whistles, but rarely does so, suggesting that the whistle is a spontaneous sound and not a form of communication. The Ganges river dolphin most typically makes echolocation sounds such as clicks, bursts, and twitters.<ref>{{Cite journal |last=Mizue |first=Kazuhiro |last2=Takemura |first2=Akira |last3=Nishiwaki |first3=Masaharu |year=1971 |title=The Underwater Sound of Ganges River Dolphins (''Platanista gangetica'') |url=http://www.icrwhale.org/pdf/SC023123-128.pdf |journal=The Scientific Reports of the Whales Research Institute |volume=23 |pages=123–128 |via=ICR}}</ref> Produced pulse trains are similar in wave form and frequency to the echolocation patterns of the [[Amazon river dolphin]]. Both species regularly produce frequencies lower than 15 kHz and the maximum frequency is thought to fall between 15 and 60 kHz.<ref name=":0" />

Echolocation is also used for population counts by using acoustic surveying. This method is still being developed and is not heavily used due to cost and technical skill requirement.<ref>{{Cite journal |last=Richman |first=Nadia I. |last2=Gibbons |first2=James M. |last3=Turvey |first3=Samuel T. |last4=Akamatsu |first4=Tomonari |last5=Ahmed |first5=Benazir |last6=Mahabub |first6=Emile |last7=Smith |first7=Brian D. |last8=Jones |first8=Julia P. G. |date=7 May 2014 |title=To See or Not to See: Investigating Detectability of Ganges River Dolphins Using a Combined Visual-Acoustic Survey |journal=PLOS ONE |language=en |volume=9 |issue=5 |pages=e96811 |bibcode=2014PLoSO...996811R |doi=10.1371/journal.pone.0096811 |pmc=4013050 |pmid=24805782 |doi-access=free}}</ref> Given the dolphin's blindness, it produces an ultrasonic sound that is echoed off other fish and water species, allowing it to identify prey.<ref>{{Cite news |last=Koshy |first=Jacob |date=2016-09-01 |title=It is pollution that made Gangetic dolphins 'blind', says Uma Bharti |language=en-IN |work=The Hindu |url=https://www.thehindu.com/news/national/other-states/It-is-pollution-that-made-Gangetic-dolphins-%E2%80%98blind%E2%80%99-says-Uma-Bharti/article14615990.ece |access-date=2021-01-10 |issn=0971-751X}}</ref>

== Reproduction ==
The dolphin does not have a specific mating season. When a calf is born, 8–12 months after conception, it will stay with its mother for one year.<ref name=":1">{{Cite web |title=Ganges River Dolphin (''Platanista gangetica gangetica'') |url=https://www.dolphins-world.com/ganges-river-dolphin/ |access-date=29 May 2018 |website=Dolphins-World}}</ref>

== Diet ==
Ganges river dolphins use echolocation to find food. They eat [[crustaceans]] such as [[prawns]] and fish including [[carp]], [[mahseer]], and even sharks such as the [[Ganges shark]] (''Glyphis gangeticus''). They may also take birds and turtles.<ref name=":1" />
[[File:GangeticDolphin.jpg|thumb|Gangetic dolphin, 1894 book illustration]]

== Human interaction ==
{{See also|Pollution of the Ganges|2014 oil spill on Sundarbans}}[[File:Ganga Kalighat 1875.jpg|thumb|Ganga on a makara by Kalighat (1875)]]The Ganges River dolphin has been listed as endangered under the IUCN Red List since 1996. Human activity has played a large role in the reduction of both their native range and population size. The Ganges river dolphin and other freshwater dolphin species have faced declines in population from stressors such as noise pollution, ship traffic, and fishery bycatch. Anthropogenic activity like dam construction and hydroelectric power plants also contribute to their endangered status.<ref>{{Cite journal |last=Sinha |first=Ravindra K. |date=2014 |title=Ganges River Dolphin: An Overview of Biology, Ecology, and Conservation Status in India |journal=Ambio |volume=43 |issue=8 |pages=1029–1046 |doi=10.1007/s13280-014-0534-7 |pmc=4235892 |pmid=24924188}}</ref> They are also endangered due to pollution and overfishing for oil.<ref name="WWF" /><ref name="iucn" /> Entanglement in fishing nets as bycatch can cause significant damage to local populations, and individuals are taken each year by hunters; their oil and meat are used as a liniment, as an [[aphrodisiac]], and as bait for [[catfish]]. Poisoning of the water supply from industrial and [[agrochemical|agricultural chemicals]] may also have been a contributing factor towards population decline, as these chemicals are biomagnified in the bodies of the dolphins.<ref>{{Cite journal |last=Kannan |first=Kurunthachalam |year=1997 |title=Sources and Accumulation of Butyltin Compounds in Ganges River Dolphin, Platanista gangetica |journal=Applied Organometallic Chemistry |volume=11 |issue=3 |pages=223–230 |doi=10.1002/(SICI)1099-0739(199703)11:3<223::AID-AOC543>3.0.CO;2-U |s2cid=59579188}}</ref> An immediate danger for the species in [[National Chambal Sanctuary]] is the decrease in river depth and appearance of sand bars dividing the river course into smaller segments, as irrigation has lowered water levels throughout their range.<ref name="Sing">{{Cite journal |last=Singh, L.A.K. |last2=R.K. Sharma |name-list-style=amp |year=1985 |title=Gangetic dolphin, ''Platanista gangetica'': Observations on habits and distribution pattern in National Chambal Sanctuary |url=http://www.geocities.com/laksingh33/ch_dol.PDF |url-status=dead |journal=Journal of the Bombay Natural History Society |publisher=Bombay Natural History Society |volume=82 |pages=648–653 |archive-url=https://web.archive.org/web/20091025035100/http://geocities.com/laksingh33/ch_dol.PDF |archive-date=25 October 2009 |df=dmy-all}}</ref>

=== Mythology and folklore ===
The Ganges dolphin is associated with [[Ganga]] and is occasionally the depiction of her [[vahana]], the [[makara]].<ref>Singh, Vijay (1994). The River Goddess. London. {{ISBN|978-1-85103-195-5}}.</ref>

== Conservation ==
{{See also|Vikramshila Gangetic Dolphin Sanctuary}}A 2017 population assessment estimated that less than 3,500 individuals of ''Platanista gangetica'' exist throughout the species' range. The underlying surveys are temporally patchy and believed to contain uncertainty.

The Ministry of Environment and Forest declared the Gangetic dolphin the national aquatic animal of India. A stretch of the Ganges River between Sultanganj and Kahlgaon in Bihar has been declared a dolphin sanctuary and named [[Vikramshila Gangetic Dolphin Sanctuary]], the first such protected area.

The Uttar Pradesh government in India is propagating ancient Hindu texts in hopes of raising the community support to save the dolphins from disappearing. One of the lines being versed from Valimiki's [[Ramayana]], highlighted the force by which the Ganges emerged from [[Shiva]]'s locks and along with this force came many species such as animals, fish, and the Shishumaar—the dolphin.<ref>{{Cite web |date=29 November 2010 |title=How Hinduism Continues to Save Dolphins in India |url=http://www.chakranews.com/how-hinduism-continues-to-save-dolphins-in-india/964 |publisher=The Chakra News}}</ref>

On 31 December 2020, a dead adult dolphin was found at the Sharda canal in the Pratapgarh district in India. A video circulated on social media showing a dozen men beating the dolphin with sticks and an axe. On 7 January 2021, three people were arrested.<ref>{{Cite web |last=Pratap |first=Rishabh Madhavendra |last2=Fox |first2=Kara |date=9 January 2021 |title=Three arrested after endangered Ganges River dolphin beaten to death in India |url=https://www.cnn.com/2021/01/09/india/india-endangered-dolphin-ganges-killed-intl/index.html |access-date=9 January 2021 |website=CNN}}</ref> Similarly, there is another news in which a few fishermen caught one Gangetic dolphin and feasted upon it leading to arrest by Kaushambhi police in Uttar Pradesh.<ref>{{Cite web |last=Desk |first=NewsGram |date=2023-07-28 |title=UP fisherman held for killing dolphin & feasting on it |url=https://www.newsgram.com/uttar-pradesh/2023/07/28/up-fisherman-held-for-killing-dolphin-feasting-on-it |access-date=2023-07-31 |website=NewsGram |language=en}}</ref>

The species is protected from international trade by its listing in Appendix I of [[CITES|the Convention on International Trade in Endangered Species of Wild Fauna and Flora]]. This makes commercial international trade prohibited.<ref name="Appendices {{!}} CITES">{{Cite web |title=Appendices {{!}} CITES |url=https://cites.org/eng/app/appendices.php |access-date=2022-01-14 |website=cites.org}}</ref>

Bangladesh has established six sanctuaries in the [[Sundarbans]].<ref>{{Cite news |last=Abu Siddique |date=26 January 2023 |title=Banned but abundant, gillnets pose main threat to Bangladesh's river dolphins |work=Mongabay |url=https://news.mongabay.com/2023/01/banned-but-abundant-gillnets-pose-main-threat-to-bangladeshs-river-dolphins/ |access-date=27 January 2023}}</ref>

=== Nonhuman personhood ===
On 20 May 2013, India's Ministry of Environment and Forests declared dolphins ‘nonhuman persons’ and as such has forbidden their captivity for entertainment purposes; keeping dolphins in captivity must satisfy certain legal prerequisites.<ref>{{Cite news |last=Gautama |first=Madhulika |date=16 June 2014 |title=Dolphins get their due |work=The Hindu |url=http://www.thehindu.com/features/kids/dolphins-get-their-due/article6119256.ece |access-date=27 November 2016 |issn=0971-751X}}</ref>

=== Project Dolphin ===
{{Main|Project Dolphin (India)}}
On the occasion of the 74th Independence Day, 15 August 2020, the Indian Ministry of Environment, Forest and Climate Change announced 'Project Dolphin' to boost conservation of both river and oceanic dolphins.<ref>{{Cite news |last=Prime Minister's Office |year=2020 |title=The Prime Minister Shri Narendra Modi addressed the Nation from the ramparts of the Red Fort on the 74th Independence Day |work=Press Information Bureau |url=https://pib.gov.in/PressReleseDetail.aspx?PRID=1646044 |access-date=16 September 2020}}</ref>

== References ==
{{Reflist}}

== External links ==
*

{{Taxonbar|from=Q210872}}
{{Symbols of India}}

[[Category:River dolphins]]
[[Category:Mammals of India]]
[[Category:Mammals of Nepal]]
[[Category:Mammals of Bangladesh]]
[[Category:Mammals described in 1801]]
[[Category:EDGE species]]
[[Category:National symbols of India]]

Ganges river dolphin - Revision history

Ajay Kumar at 05:24, 29 August 2023