Green sea turtle: Difference between revisions - Wikipedia

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[[File:Chelonia.svg|thumb|Escalation of [[carapace]] and [[plastron]]|alt=Drawing of turtle carapace and plastron showing respectively, vertebral, costal, marginal, and supracaudal and intergular, gular, pectoral, abdominal, humeral, femoral, anal, axillary (anterior inframarginal), and inguinal (posterior inframarginal) shields]]

[[File:Taxidermy of turtle shell (Chelonia mydas).jpg|thumb|Taxidermied shell of ''Chelonia mydas'']]

Its appearance is that of a typical [[sea turtle]]. ''C. mydas'' has a dorsoventrally flattened body, a beaked head at the end of a short neck, and paddle-like arms well-adapted for swimming.<ref name="FWS">{{cite web|url=https://www.fws.gov/northflorida/SeaTurtles/Turtle%20Factsheets/green-sea-turtle.htm|title=Green sea turtle (''Chelonia mydas'')|date=December 29, 2005|publisher=United States Fish and Wildlife Service|work=North Florida Field Office|access-date=February 21, 2007|archive-date=June 29, 2017|archive-url=https://web.archive.org/web/20170629221452/https://www.fws.gov/northflorida//SeaTurtles/Turtle%20Factsheets/green-sea-turtle.htm|url-status=dead}}</ref> Adult green turtles grow to {{convert|1.5|m|ft|0}} long.<ref name="Animal">{{cite book|title=Animal|last=Kindersley|first=Dorling|publisher=DK Publishing|year=2005|isbn=978-0-7894-7764-4|location=New York City}}</ref> The average weight of mature individuals is {{convert|68|-|190|kg|lb|abbr=on}} and the average carapace length is {{convert|78|-|112|cm|in|abbr=on}}.<ref>{{Cite web |url=http://www.seaworld.org/animal-info/info-books/sea-turtle/physical-characteristics.htm |title=SEA TURTLES - Physical Characteristics |access-date=2012-04-03 |archive-url=https://web.archive.org/web/20130728212355/http://www.seaworld.org/animal-info/info-books/sea-turtle/physical-characteristics.htm |archive-date=2013-07-28 |url-status=dead }}</ref>. They are considerd the second largest sea turtle in the United States, with Leatherback Sea Turtle being the largest.<ref>{{cite journal |last1=Sonmez |first1=Bektas |title="Morphological variations in the green turtle (Chelonia mydas): A field study on an eastern Mediterranean nesting population" |journal=Zoological Studies 58 |date=2019}}</ref>

Exceptional specimens can weigh {{convert|315|kg|lb|abbr=on}} or even more, with the largest known ''C. mydas'' having weighed {{convert|395|kg|lb|abbr=on}} and measured {{convert|153|cm|in|abbr=on}} in carapace length.<ref name="CCC">{{cite web|url=http://www.cccturtle.org/green.htm|title=Species Fact Sheet: Green Sea Turtle|date=December 29, 2005|publisher=Caribbean Conservation Corporation|work=Caribbean Conservation Corporation & Sea Turtle Survival League|access-date=February 22, 2007|url-status=dead|archive-url=https://web.archive.org/web/20070224150825/http://www.cccturtle.org/green.htm|archive-date=February 24, 2007}}</ref>

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Mating behaviour is similar to other marine turtles. Female turtles control the process. A few populations practice [[Polyandry in animals|polyandry]], although this does not seem to benefit hatchlings.<ref name="Lee2004">{{cite journal |last =Lee |first =Patricia L. M. |author-link =Patricia Lee |author2=[[Graeme Hays|Graeme C. Hays]] |title =Polyandry in a marine turtle: Females make the best of a bad job |journal =Proceedings of the National Academy of Sciences |volume =101 |issue =17 |pages =6530–6535 |date =April 27, 2004 |doi =10.1073/pnas.0307982101|pmid =15096623 |pmc =404079|bibcode =2004PNAS..101.6530L |doi-access =free }}</ref> After mating in the water, the female moves above the beach's high tide line, where she digs a hole {{convert|11|–|22|in|cm|order=flip}} in depth with her hind flippers and deposits her eggs. The hole is then covered up again.<ref name=":6">{{Cite book|title=Turtles of the World|last=Bonin|first=Franck|publisher=The Johns Hopkins University Press Baltimore|year=2006|isbn=978-0-8018-8496-2|location=Baltimore, Maryland|url-access=registration|url=https://archive.org/details/turtlesofworld0000boni}}</ref> Clutch size ranges between 85 and 200, depending on the age of the female. This process takes about an hour to an hour and a half. After the nest is completely covered, she returns to the sea. The female will do this 3 to 5 times in one season.<ref name=":4" />

The eggs are round and white, and about {{convert|45|mm|abbr=on}} in diameter. The hatchlings remain buried for days until they all emerge together at night.<ref name=":6" /> The temperature of the nest [[temperature-dependent sex determination|determines the sex]] of the turtles at around the 20–40 day mark. Green Sea Turtles are type 1a, meaning males develop at cooler temperatures while females are produced under hot temperatures. <ref>{{cite journal |last1=Standora |first1=Edward A |last2=Spotila |first2=James R. |title="Temperature dependent sex determination in sea turtles" |journal=Copeia |date=1985 |pagepages=711-722711–722}}</ref><ref>Spotila, J. R. (2004). Sea turtles: a complete guide to their biology, behavior, and conservation. Baltimore: Johns Hopkins University Press.</ref> At around 50 to 70 days,<ref>{{Cite web|title = Green turtle|url = http://wwf.panda.org/what_we_do/endangered_species/marine_turtles/green_turtle/|website = wwf.panda.org|access-date = 2015-10-19}}</ref> the eggs hatch during the night, and the hatchlings [[instinct]]ively head directly into the water. This is the most dangerous time in a turtle's life. As they walk, predators, such as [[gull]]s and [[crab]]s, feed on them. A significant percentage never make it to the ocean. Little is known of the initial life history of newly hatched sea turtles.<ref name="FWS"/> Juveniles spend three to five years in the open ocean before they settle as still-immature juveniles into their permanent shallow-water lifestyle.<ref name="Reich2007"/><ref name="LS20070918"/> It is speculated that they take twenty to fifty years to reach [[sexual maturity]]. Individuals live up to eighty years in the wild.<ref name="NGeo"/> It is estimated that only 1% of hatchlings reach sexual maturity.

Each year on [[Ascension Island]] in the [[South Atlantic]], ''C. mydas'' females create 6,000 to 25,000 nests. They are among the largest green turtles in the world; many are more than {{convert|1|m}} in length and weigh up to {{convert|300|kg|lb}}.<ref name="AscensionGT">{{cite web |last =Fowler |first =Stephen |title =About The Green Turtle on Ascension |work =Turtles |publisher =Ascension Island Heritage Society |date =April 21, 2002 |url =http://www.heritage.org.ac/HS2right.htm |access-date =September 16, 2007 |archive-date =October 30, 2007 |archive-url =https://web.archive.org/web/20071030074741/http://www.heritage.org.ac/HS2right.htm |url-status =dead }}</ref>

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== Unique characteristics and features ==

Green sea turtles can reach up to 40 miles per hour when swimming, making them the fastest sea turtle.<ref>{{cite journal |last1=Meylan |first1=Peter A. |last2=Meylan |first2=Anne B. |last3=Gray |first3=Jennifer A. |title=The ecology and migrations of sea turtles 8. Tests of the developmental habitat hypothesis." |journal=Bulletin of the American Museum of Natural History |date=2011 |pagepages=1-701–70}}</ref> The green sea turtles exhibit sex differences by their development and appearance. As adult turtles, males are easily distinguishable from the females by having a longer tail (visibly extending past the shell) and longer claws on the front flippers. The hatching time and sex of the turtles are determined by the incubation temperature of the nest. Hatchings occur more quickly in nests that are warmer than nests that are in cooler conditions. Warm nesting sites above 30 degrees Celsius favor the development of females, whereas nesting sites below 30 degrees Celsius produce males. The position of the egg in the nest also affects sex-determination. Eggs in the center tend to hatch as females due to the warmer conditions within the nest.<ref name=":2">{{Cite book|last=Spotila|first=J.|year=2004|title=Sea Turtles: A Complete Guide to their Biology, Behavior, and Conservation|location=Baltimore, MD|publisher=Johns Hopkins University Press}}</ref>

Green sea turtles play an essential role in the ecosystem in which they live. In the seagrass beds, the turtles feed on the seagrass by trimming only the top and leaving the roots of the plant. Through their feeding technique, the turtles help to improve the health and growth of the seagrass beds. The healthy seagrass beds that the turtles provide give habitat and feeding grounds for many species of fish and crustaceans. On the nesting beaches, the green sea turtles provide key nutrients for the ecosystem through their hatched egg shells. In their coral reef habitat, the green sea turtles have a [[Symbiosis|symbiotic interaction]] with reef fish, including the yellow tang. The yellow tang fish swims along with the turtle and feeds on the algae, barnacles, and parasites on its shell and flippers. This species interaction provides food for the yellow tang and provides a necessary cleaning and smoothing of the turtle's shell. This cleaning helps the turtles swim by reducing the amount of drag and improves their health.<ref name=":3" />

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Sea turtles are integral to the history and culture of the [[Cayman Islands]]. When the islands were first discovered by [[Christopher Columbus]] in 1503, he named them "Las Tortugas" because of the abundance of sea turtles in the waters around the islands.<ref name="Turtle release set">{{cite news|title=Turtle release set|url=http://www.compasscayman.com/caycompass/2007/10/24/Turtle-release-set/|newspaper=Caymanian Compass|date=October 23, 2007|access-date=April 9, 2012|archive-date=September 23, 2015|archive-url=https://web.archive.org/web/20150923205736/http://www.compasscayman.com/caycompass/2007/10/24/Turtle-release-set/|url-status=dead}}</ref> Many of the earliest visitors came to the [[Cayman Islands]] to capture the turtles as a source of fresh meat during long voyages. The green turtle is a national symbol displayed as part of the [[coat of arms of the Cayman Islands]], which also forms part of the national [[flag of the Cayman Islands]]. The country's currency uses a turtle as the watermark in its banknotes.<ref>{{cite news|title=Fresh, new banknotes ready|newspaper=Caymanian Compass|date=April 6, 2011|url=http://www.compasscayman.com/caycompass/2011/04/06/Fresh,-new-banknotes-ready/|access-date=April 9, 2012|archive-date=September 23, 2015|archive-url=https://web.archive.org/web/20150923205747/http://www.compasscayman.com/caycompass/2011/04/06/Fresh,-new-banknotes-ready/|url-status=dead}}</ref> A stylised sea turtle nicknamed "Sir Turtle" is the mascot of the national airline [[Cayman Airways]]<ref>{{cite news|last=McGowan|first=Cliodhna|title=Sir Turtle to keep flying|newspaper=Caymanian Compass|date=May 13, 2007|url=http://www.compasscayman.com/caycompass/2007/05/14/Sir-Turtle-to-keep-flying/}}</ref> and is part of the livery of its aircraft.

A ki'i pōhaku ([[petroglyph]]) of a green sea turtle (or honu) can be found on the [[Big Island of Hawaii]] in the Pu'u Loa lava fields. The green sea turtle has always held a special meaning for [[Hawaiians]] and this petroglyph shows its importance; it may date to when the [[Hawaiian Islands]] first became populated. The turtle symbolizes a navigator that can find his way home time after time. This symbol mirrors the real life of the green Hawaiian turtle as it will swim hundreds of miles to lay its eggs at its own place of birth. Though there are other myths as well, some Hawaiian legends say the honu were the first to guide the [[Polynesians]] to the Hawaiian Islands. Hawaiians revere the turtle and the legend of Kailua, a turtle who could take the form of a girl at will. In human form, she looked after the children playing on [[Punalu'u Beach]]. <ref>{{Cite web |url=http://www.hawaiianlife.com/content/hawaiian-honu-and-its-meaning |title=www.HawaiianLife.com |access-date=2014-12-29 |archive-date=2014-12-29 |archive-url=https://web.archive.org/web/20141229230203/http://www.hawaiianlife.com/content/hawaiian-honu-and-its-meaning |url-status=dead }}</ref>

==Conservation==

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In the Atlantic, conservation initiatives have centered around Caribbean nesting sites. The Tortuguero nesting beaches in [[Costa Rica]] have been the subject of egg-collection limits since the 1950s. The [[Tortuguero National Park]] was formally established in 1976, in part, to protect that region's nesting grounds.<ref name="Bjorndal1999CostaRica"/> On [[Ascension Island]], which contains some of the most important nesting beaches, an active conservation program has been implemented.<ref name="AscensionConservation">{{cite web |title =Ascension Conservation |work =Ascension Conservation, Wildlife |publisher =Ascension Conservation |year =2007 |url =http://www.ascensionconservation.org.ac/wildlife.htm |access-date =September 16, 2007 |url-status =dead |archive-url =https://web.archive.org/web/20070928054657/http://www.ascensionconservation.org.ac/wildlife.htm |archive-date =September 28, 2007 }}</ref> Karumbé has been monitoring foraging and developmental areas of juvenile green turtles in Uruguay since 1999.<ref>{{Cite web|url=http://www.karumbe.org/|title=Karumbé &#124; Centro de Tortugas marinas|website=www.karumbe.org}}</ref>

In Mozambique, there are a number of initiatives to protect sea turtles. In the [[Primeiras and Segundas Archipelago|Primeiras e Segundas]], [[World Wildlife Fund|WWF]] Mozambique has established a turtle tagging and protection program. The archipelego is a vital nesting area for green turtles, including [[Ilha do Fogo, Mozambique|Ilha do Fogo]] where Fire Island Conservation<ref>{{Cite web |title=Fire Island Conservation {{!}} Saving Sea Turtles |url=https://fireislandconservation.com/saving-sea-turtles/ |website=Fire Island Conservation|date=23 October 2023 }}</ref> manage a turtle monitoring programme, and at Celdeira Island, where several nesting females have been tagged.

[[Cayman Turtle Farm]] located in Grand Cayman in the northwest Caribbean Sea is the first farm to have achieved the second generation of green sea turtles bred, laid, hatched, and raised in captivity.<ref>{{cite web|title=History: 1989|url=http://www.turtle.ky/history-history|publisher=Cayman Turtle Farm|access-date=April 9, 2012|archive-date=June 12, 2015|archive-url=https://web.archive.org/web/20150612155633/http://www.turtle.ky/history-history|url-status=dead}}</ref> Since its beginning in 1968, the farm has released over 31,000 turtles into the wild,<ref name="Turtle release set"/> and each year more captive-bred turtles are released into the [[Caribbean Sea]] from beaches around the island of [[Grand Cayman]].<ref>{{cite news|last=Fuller|first=Brent|title=Little turtles swimming for it|url=http://www.compasscayman.com/caycompass/2011/11/18/Little-turtles-swimming-for-it/|newspaper=Caymanian Compass|date=November 18, 2011|access-date=April 9, 2012|archive-date=September 23, 2015|archive-url=https://web.archive.org/web/20150923205753/http://www.compasscayman.com/caycompass/2011/11/18/Little-turtles-swimming-for-it/|url-status=dead}}</ref> Captive-bred turtles released from the farm as hatchlings or yearlings with "living tags," have now begun to return to nest on Grand Cayman as adults.<ref>{{cite journal|last=Bell|first=Catherine|author2=Parsons J |author3=Austin TJ |author4=Broderick AC |author5=Ebanks-Petrie G |author6=Godley GJ |title=Some of them came home: the Cayman Turtle Farm headstarting project for the green turtle ''Chelonia mydas''|journal=Oryx|date=25 April 2005|volume=39|pages=137–148|doi=10.1017/S0030605305000372|issue=2|doi-access=free}}</ref><ref>{{cite news|last=Connolly|first=Norma|title=More turtles nesting in Cayman|url=http://www.compasscayman.com/caycompass/2011/06/02/More-turtles-nesting-in-Cayman/|newspaper=Caymanian Compass|date=June 2, 2011|quote=five turtles with tags from the Cayman Turtle Farm were observed nesting on Seven Mile Beach|access-date=April 9, 2012|archive-date=September 23, 2015|archive-url=https://web.archive.org/web/20150923205749/http://www.compasscayman.com/caycompass/2011/06/02/More-turtles-nesting-in-Cayman/|url-status=dead}}</ref> On February 19, 2012 the farm released the first 2nd-generation captive-bred green sea turtle equipped with a Position Tracking Transponder, or PTT<ref>{{Cite web|url=http://www.seaturtle.org/tracking/index.shtml?tag_id=112227&full=1|title=seaturtle.org - Satellite Tracking|website=www.seaturtle.org}}</ref> (also known as a satellite tag).<ref>{{cite web|title=Cayman Turtle Farm Green Sea Turtle Releases|url=http://www.seaturtle.org/tracking/index.shtml?tag_id=112227|publisher=SeaTurtle.org|access-date=April 9, 2012|author=Cayman Turtle Farm}}</ref> In addition, the farm provides turtle meat products to the local population for whom turtle has been part of the traditional cuisine for centuries. In so doing, the farm curtails the incentive to take turtles from the wild,<ref>{{cite news|last=Brammer|first=Jeff|title=What if the turtle farm went belly up?|url=http://www.compasscayman.com/caycompass/blogs/whatifcolumn/What-if-the-turtle-farm-went-belly-up-/|newspaper=Caymanian Compass|date=October 16, 2011|quote=presenting disincentives to poachers due to the commercial availability of turtle meat|access-date=April 9, 2012|archive-date=September 23, 2015|archive-url=https://web.archive.org/web/20150923205911/http://www.compasscayman.com/caycompass/blogs/whatifcolumn/What-if-the-turtle-farm-went-belly-up-/|url-status=dead}}</ref> which over the years in addition to the Cayman Turtle Farm's release of captive-bred turtles has enabled an increase in the number of turtles sighted in the waters around the island of [[Grand Cayman]] and nesting on its beaches.<ref>{{cite news|last=Connolly|first=Norma|title=More turtles nesting in Cayman|url=http://www.compasscayman.com/caycompass/2011/06/02/More-turtles-nesting-in-Cayman|newspaper=Caymanian Compass|date=June 2, 2011|quote=(Quoted Ebanks-Petrie, Gina and Blumenthal, Janice of Department of the Environment, Cayman Islands)|access-date=April 9, 2012|archive-date=September 23, 2015|archive-url=https://web.archive.org/web/20150923205749/http://www.compasscayman.com/caycompass/2011/06/02/More-turtles-nesting-in-Cayman/|url-status=dead}}</ref>