Editing Commerson's dolphin

{{Short description|Species of mammal}}
{{Use dmy dates|date=December 2014}}
{{Speciesbox
| name = Commerson's dolphin<ref name=MSW3>{{MSW3 Cetacea|id=14300037}}</ref>
| image = Tonina1 (2731842634).jpg
| image_caption = A Commerson's dolphin in [[Chubut Province]].
| image2 = Commerson's dolphin size.svg
| image2_caption = Size compared to an average human
| status = LC
| status_system = IUCN3.1
| status_ref =<ref name="iucn">{{cite iucn |author=Crespo, E. |author2=Olavarria, C. |author3=Dellabianca, N. |author4=Iñíguez, M. |author5=Ridoux, V. |author6=Reeves, R. |year=2017 |errata=2018 |title=''Cephalorhynchus commersonii'' |volume=2017 |page=e.T4159A128963283 |doi= |access-date=30 December 2018}}</ref>
| status2 = CITES_A2 
| status2_system = CITES 
| status2_ref = <ref>{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref>
| genus = Cephalorhynchus
| species = commersonii
| authority = [[Bernard Germain Étienne de la Ville, Comte de Lacépède|Lacépède]], 1804
| range_map = Commerson's dolphin South America distribution.png
| range_map_caption = ''C. c. commersonii'' distribution near South America
| range_map2 = Commerson's dolphin Kerguelen Island distribution.png
| range_map2_caption = ''C. c. kerguelensis'' distribution near the Kerguelen Islands
| subdivision_ranks = Subspecies
| subdivision =
*''C. c .commersonii''
*''C. c .kerguelensis''
}}

'''Commerson's dolphin''' ('''''Cephalorhynchus commersonii'''''), also referred to by the common names '''jacobita''', '''skunk dolphin''', '''piebald dolphin''', '''panda dolphin''', or '''tonina overa''' (in South America), is a small [[oceanic dolphin]] of the genus ''[[Cephalorhynchus]]''. Commerson's dolphin has two geographically isolated but locally common subspecies. The principal subspecies, ''C.c.commersonii'', has sharply-delineated black-and-white patterning and is found around the tip of South America. The secondary subspecies, ''C.c.kerguelenensis'', is larger than ''C.c.commersonii'', has a less-sharply delineated dark and light grey patterning with a white ventral band, and is found around the [[Kerguelen Islands]] in the Indian Ocean.

The dolphin is named after French naturalist Dr [[Philibert Commerson]], who first described them in 1767 after sighting them in the [[Strait of Magellan]].<ref>''Sharks and Whales'' (Carwardine et al. 2002), p. 370.</ref>

==Population and distribution==
Two disjunct subspecies of the dolphin are found in geographically disparate areas separated by 130° of longitude and about {{convert|8500|km|abbr=on}}; it is not known why they are thus distributed. Global populations are unknown, but the species is accepted to be locally common.<ref>{{Cite journal |last1=Pimper |first1=Lida E. |last2=Remis |first2=Maria I. |last3=Natalie |first3=R. |last4=Goodall |first4=P. |last5=Baker |first5=C. Scott |date=2009-09-01 |title=Teeth and Bones as Sources of DNA for Genetic Diversity and Sex Identification of Commerson's Dolphins (''Cephalorhynchus commersonii'') from Tierra del Fuego, Argentina |journal=Aquatic Mammals |volume=35 |issue=3 |pages=330–333 |doi=10.1578/am.35.3.2009.330 |issn=0167-5427}}</ref>

The main subspecies, ''C.c.commersonii'', is found inshore in various inlets in Argentina including [[Puerto Deseado]], in the [[Strait of Magellan]] and around [[Tierra del Fuego]], and near the [[Falkland Islands]] (Las Malvinas).<ref name=Righi>{{Cite journal |last1=Righi |first1=Carina F. |last2=Blanco |first2=Gabriela S. |last3=Frere |first3=Esteban |date=March 2013 |title=Abundance and Spatial Distribution of Commerson's Dolphin (Cephalorhynchus commersonii) at a Breeding Site: Ría Deseado, Patagonia, Argentina |journal=Aquatic Mammals |volume=39 |issue=1 |pages=1–9 |doi=10.1578/am.39.1.2013.1 |issn=0167-5427|hdl=11336/23945 |hdl-access=free }}</ref> A survey in 1984 estimated there to be 3,200 individuals in the Strait of Magellan. <ref name="Estimate of number of Commerson's dolphins in a portion of the northeastern Strait of Magellan, January-February 1984">{{cite journal |last1=Leatherwood |first1=S. |last2=Kastelein |first2=R. A. |last3=Hammond |first3=P. S. |title=Estimate of number of Commerson's dolphins in a portion of the northeastern Strait of Magellan, January-February 1984 |journal=Reports of the International Whaling Commission |date=1988 |volume=9 |pages=93–102}}</ref>

Dolphins of the second subspecies, ''C.c.kerguelenensis'', were discovered in the 1950s. They reside near the [[Kerguelen Islands]], in the southern part of the [[Indian Ocean]], and prefer shallow waters.

In 2004, a [[Vagrancy (biology)|vagrant]] individual of unconfirmed origin was sighted on [[South Africa|South Africa's]] [[Agulhas Bank]], {{Convert|4200|km|abbr=on}} from the Kerguelen Islands and {{Convert|6300|km|abbr=on}} from South America. Though the Kerguelen Islands are closer, such a journey would require swimming against the [[Antarctic Circumpolar Current]].<ref>{{Cite journal | last1 = Bruyn | first1 = P. J. N., de | last2 = Hofmeyr | first2 = G. J. G. | last3 = Villiers | first3 = M. S., de | title = First record of a vagrant Commerson's dolphin, ''Cephalorhynchus commersonii'', at the southern African continental shelf | year = 2006 | journal = African Zoology | volume = 41 | issue = 1 | url = http://www.biologicalsciences.uct.ac.za/sites/default/files/image_tool/images/75/files/de%20Bruyn_Commersons.pdf | access-date = 15 February 2015 | archive-date = 9 May 2021 | archive-url = https://web.archive.org/web/20210509190352/https://www.biologicalsciences.uct.ac.za/sites/default/files/image_tool/images/75/files/de%20Bruyn_Commersons.pdf | url-status = dead }}</ref>

==Description==

===''Cephalorhynchus commersonii commersonii''===
[[File:Commerson Dolphin closer.jpg|left|thumb|Commerson's dolphins in the [[Strait of Magellan]]]]
The ''commersonii'' subspecies has a black head, [[dorsal fin]], and [[fluke (tail)|fluke]], with a white throat and body. The demarcation between the two colours is very clear-cut. This stocky creature is one of the smallest of all [[cetaceans]], growing to around 1.5&nbsp;m (5&nbsp;ft). A mature female caught off of southern [[Patagonia]], at 23&nbsp;kg (51&nbsp;lb) and 1.36&nbsp;m (4.5&nbsp;ft), may be the smallest adult cetacean on record.<ref>Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc. (1983), {{ISBN|978-0-85112-235-9}}</ref> Its appearance resembles that of a [[porpoise]], but its conspicuous [[Commerson's dolphin#Behaviour|behaviour]] is typical of a dolphin. The dorsal fin has a long, straight leading edge which ends in a curved tip. The trailing edge is typically [[wikt:concave|concave]], but not [[falcate]]. The fluke has a notch in the middle.

Sexes are easily distinguished by the different shape of the black blotch on the belly&nbsp;— it is shaped like a teardrop in males but is more rounded in females. Females reach breeding age at 6 to 9 years. Males reach sexual maturity at about the same age. Mating occurs in the spring and summer and calving occurs after a gestation period of 11 months during the spring and summer.<ref name=Righi/><ref>{{Cite journal |last1=Sakai |first1=Mai |last2=Morisaka |first2=Tadamichi |last3=Iwasaki |first3=Mari |last4=Yoshida |first4=Yayoi |last5=Wakabayashi |first5=Ikuo |last6=Seko |first6=Atsushi |last7=Kasamatsu |first7=Masahiko |last8=Kohshima |first8=Shiro |date=2013-07-04 |title=Mother–calf interactions and social behavior development in Commerson's dolphins (''Cephalorhynchus commersonii'') |journal=Journal of Ethology |volume=31 |issue=3 |pages=305–313 |doi=10.1007/s10164-013-0380-2 |s2cid=11054565 |issn=0289-0771|doi-access=free |hdl=2433/193101 |hdl-access=free }}</ref> The Commerson's dolphin has been known to live up to 18 years in the wild, while in captivity the oldest individual was at least 33 years old at the time of death.<ref>{{cite web |author=Pedicini, Sandra |date=February 1, 2016 |website=[[Orlando Sentinel]] |url=http://www.orlandosentinel.com/business/tourism/os-seaworld-commersons-dolphins-20160201-story.html |title=Unusual Commerson's dolphins' time at SeaWorld's Aquatica coming to a close}}</ref>

===''Cephalorhynchus commersonii kerguelenensis''===
Dolphins of the ''kerguelenensis'' subspecies tend to be larger than those of ''C.c.commersonii'', and differ in patterning in that they are dark grey instead of black, and light grey instead of white, except ventrally. The demarcation between areas of the pattern is also less clear.<ref>{{cite book|last1=Jefferson|first1=Thomas A.|last2=Webber|first2=Marc A. J. G. M.|last3=Pitman |first3=Robert L.|title=Marine mammals of the world: a comprehensive guide to their identification |date=2008|publisher=Academic|location=London|isbn=978-0-12-383853-7|page=263|edition=1st |url=https://books.google.com/books?id=TwFUimDtz7sC&pg=PA263|access-date=8 December 2015}}</ref>

==Behavior==
Commerson's dolphin is very active. It is often seen swimming rapidly on the surface and leaping from the water. It also spins and twists as it swims and may surf on breaking waves when very close to the shore. It will bow-ride and swim behind fast-moving boats. It is also known to swim upside-down, which is thought to improve the visibility of its prey.

This dolphin feeds on a mix of coastal and [[pelagic fish]] and [[squid]]. Those in the South American subpopulation supplement their diets with [[crustacean]]s.<ref>{{Cite journal |last1=Kastelein |first1=R. A. |last2=McBain |first2=J. |last3=Neurohr |first3=B. |date=1993 |title=Information on the biology of Commerson's dolphins (''Cephalorhynchus commersonii'') |journal=Aquatic Mammals |volume=19 |issue=1 |pages=13–19 |url=https://core.ac.uk/download/pdf/29322129.pdf#page=193}}</ref><ref>{{Cite book |last1=Brownell |first1=Robert L. |last2=Donovan |first2=Gregory P. |title=Biology of the genus Cephalorhynchus |date=1988 |publisher=International Whaling Commission |isbn=0-906975-17-4 |oclc=19253432}}</ref><ref>{{Cite journal |last1=Kastelein |first1=R. |last2=McBain |first2=J. |last3=Neurohr |first3=B. |last4=Mohri |first4=M. |last5=Sayo |first5=S. |last6=Wakabayaski |first6=I. |last7=Wiepkema |first7=P.R. |date=1993 |title=The food consumption of Commerson's dolphins (''Cephalorhynchus commersonii'') |journal=Aquatic Mammals |volume=19 |issue=2 |pages=99–121 |url=https://www.researchgate.net/publication/40183835}}</ref> Individuals have been recorded as entering the Santa Cruz River to forage there during low tide.<ref name="Loizaga de Castro">{{cite journal |last1=Loizaga de Castro |first1=Rocio |last2=Dans |first2=Silvana Laura |last3=Coscarella |first3=Mariano Alberto |last4=Crepso |first4=Enrique Alberto |title=Living in an estuary: Commerson´s dolphin (''Cephalorhynchus commersonii'' (Lacépède, 1804)), habitat use and behavioural pattern at the Santa Cruz River, Patagonia, Argentina |journal=Latin American Journal of Aquatic Research |date=2013 |volume=41 |issue=5 |pages=985–991 |doi=10.3856/vol41-issue5-fulltext-17 |eissn=0718-560X |url=https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0718-560X2013000500017&lng=es&nrm=iso&tlng=en |access-date=11 December 2018 |via=SciELO }}</ref>

They can be found in estuaries, especially during the breeding season.<ref name=Righi/><ref name="Loizaga de Castro"/>

==Conservation==
The [[IUCN]] lists Commerson's dolphin as [[Least Concern]] in its [[Red List of Threatened Species]]. The proximity of the dolphin to the shore makes accidental killing in [[gillnet]]s a common occurrence. The dolphin was killed for use as crab [[bait (luring substance)|bait]] by some Argentinian and Chilean fishermen in the 1970s and 1980s, but this practice has since been curtailed.<ref name="iucn" />

The Commerson's dolphin population of South America is listed in Appendix II of the [[Convention on the Conservation of Migratory Species of Wild Animals]] (CMS) because it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.<ref>{{Cite web |url=http://www.cms.int/reports/small_cetaceans/data/c_commersonii/c_commersonii.htm |title=Convention on Migratory Species page on the Commerson's dolphin |access-date=31 August 2011 |archive-url=https://web.archive.org/web/20160303230932/http://www.cms.int/reports/small_cetaceans/data/c_commersonii/c_commersonii.htm |archive-date=3 March 2016 |url-status=dead }}</ref><ref name="Appendices">Appendix II of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008. Effective: 5 March 2009.[http://www.cms.int/documents/appendix/Appendices_COP9_E.pdf]{{webarchive|url=https://web.archive.org/web/20110611112003/http://www.cms.int/documents/appendix/Appendices_COP9_E.pdf|date=11 June 2011}}</ref>

==Captivity==
These dolphins have been known to be displayed in a few aquariums.<ref>{{cite web |last1=Batt |first1=Elizabeth |date=20 October 2014 |title=CAPTIVE COMMERSON'S DOLPHINS IN NORTH AMERICA |website=The Dolphin Project |url=https://www.dolphinproject.com/blog/captive-commersons-dolphins-in-north-america/ |access-date=11 December 2018}}</ref><ref>{{cite journal |last1=Gewalt |first1=Wolfgang |title=The Jacobita, or Commerson's dolphin (''Cephalorhynchus commersonii'') |journal=Aquatic Mammals |date=1990 |volume=16 |issue=2 |pages=53–64}}</ref>

==See also==
{{Portal|Cetaceans|Mammals|Marine life}}
*[[List of cetaceans]]

==References==
{{Commons category|Cephalorhynchus commersonii}}
{{Wikispecies|Cephalorhynchus commersonii}}
{{Reflist}}
*''National Audubon Society: Guide to Marine Mammals of the World'' {{ISBN|0-375-41141-0}}
*''Encyclopedia of Marine Mammals'' {{ISBN|0-12-551340-2}}
*''The Sierra Club Handbook of Whales and Dolphins''

==External links==
{{Cetacea|O.}}
{{Taxonbar|from=Q724354}}

[[Category:Cephalorhynchus|Heaveside's dolphin]]
[[Category:Mammals of Argentina]]
[[Category:Mammals of Chile]]
[[Category:Marine fauna of South America]]
[[Category:Cetaceans of the Atlantic Ocean]]
[[Category:Cetaceans of the Indian Ocean]]
[[Category:Fauna of Patagonia]]
[[Category:Fauna of Tierra del Fuego]]
[[Category:Fauna of the Kerguelen Islands]]
[[Category:Fauna of Temperate South America]]
[[Category:Mammals described in 1804|Commerson's dolphin]]
[[Category:Taxa named by Bernard Germain de Lacépède|Commerson's dolphin]]