Animal Diversity Web

Ge­o­graphic Range

Green sea tur­tles (Ch­e­lo­nia mydas) are a cos­mopoli­tan species found in trop­i­cal and sub­trop­i­cal wa­ters. Dur­ing the months that this species breeds (June through Au­gust), green sea tur­tles are most fre­quently found nest­ing on the coast­lines of Cyprus and Turkey. They are also ob­served nest­ing on the beaches of Is­rael, Syria, Egypt and Libya. Over­all, green tur­tles are known to set­tle on the beaches of over 140 coun­tries. Radio tag­ging nest­ing fe­males shows that green tur­tles are mi­gra­tory, and their non-breed­ing range in­cludes lo­ca­tions from as far north as 40 de­grees north to as far south as 40 de­grees south. These areas in­clude parts of the Pa­cific Ocean, At­lantic Ocean, Mediter­ranean Sea, and north­ern In­dian Ocean. ("Sta­tus and dis­tri­b­u­tion of the green tur­tle, Ch­e­lo­nia mydas, in the wider Caribbean re­gion", 2001; Hirth, 1997; Semi­noff, 2004; Stokes, et al., 2015)

• Biogeographic Regions
• indian ocean
  • native
• atlantic ocean
  • native
• pacific ocean
  • native
• mediterranean sea
  • native

• Other Geographic Terms
• cosmopolitan

Habi­tat

Green sea tur­tles are com­mon in shal­low trop­i­cal and sub­trop­i­cal wa­ters as well as coast­line beaches. They for­age in coastal areas with plen­ti­ful of algae and sea grass. Male and fe­male green tur­tles use major cur­rent sys­tems when mi­grat­ing to nest­ing beaches. Once fe­males find a suit­able beach with ac­ces­si­ble slop­ing plat­forms, the green tur­tles will lay their eggs in the sand and then re­turn to the ocean. After the eggs hatch, ju­ve­nile green sea tur­tles will then re­turn to the ocean. Ju­ve­niles are known to spend sev­eral years drift­ing in the open ocean as they grow and ma­ture. Once the ju­ve­niles have ma­tured, they will re­turn to their natal beach for mat­ing. ("Green sea tur­tle (Ch­e­lo­nia mydas)", 2015; Semi­noff, 2004; Stokes, et al., 2015)

• Habitat Regions
• tropical
• terrestrial
• saltwater or marine

• Aquatic Biomes
• pelagic
• reef
• coastal

Phys­i­cal De­scrip­tion

Green sea tur­tles are so named be­cause of the green­ish color of their sub­der­mal fat. They have only one pair of pre­frontal scales, al­though other species of sea tur­tles that have mul­ti­ple pairs. The scales are orig­i­nally black at hatch­ing, but then change color over the course of 27-50 years as the tur­tle ma­tures. Their skull shape is de­scribed as round and smooth. Green tur­tles have short snouts and strong beaks that cover the bones of the jaw. Their jaws are short and ser­rated to prop­erly rip and tear plants apart. The cara­pace is round and con­sists of four lat­eral over­lap­ping scutes. The plas­tron also con­sists of four scutes.

Sex­ual di­mor­phism isn't com­pletely rec­og­nized in green sea tur­tles until early adult­hood. Males and fe­males dif­fer mor­pho­log­i­cally by the length of their tail and cloa­cal open­ings. Fe­male green tur­tles have smaller tails and a cloa­cal open­ing be­tween the anus and tip of the tail. Witzel (1982) re­ports that that male green tur­tles are slightly smaller in cara­pace length, have longer claws, and longer tails where their re­pro­duc­tive or­gans are lo­cated. Their cloa­cal open­ing is lo­cated more pos­te­rior on the tail and past the end of their cara­pace.

Green tur­tles are the sec­ond largest over­all species of sea tur­tles. As hatch­lings, green tur­tles have an av­er­age weight of 25g and are 5 cm long. Their plas­trons are white and cara­paces are blue-black. Ju­ve­niles mea­sure to about 40 cm in cara­pace length and subadults will mea­sure be­tween 70 to 100 cm. Adult green tur­tles, male or fe­male, tend to be about 100 to 120 cm long in cara­pace length and weigh around 150 to 200 kg when reach­ing adult­hood. They also have a basal meta­bolic rate of 47.9 to 73.8 cm^3 oxy­gen/hour. ("Sta­tus and dis­tri­b­u­tion of the green tur­tle, Ch­e­lo­nia mydas, in the wider Caribbean re­gion", 2001; "The anatomy of sea tur­tles", 2001; Witzel, 1982)

• Other Physical Features
• ectothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger
• sexes shaped differently

• Range mass

  150 to 200 kg

  330.40 to 440.53 lb

• Range length

  100 to 120 cm

  39.37 to 47.24 in

• Range basal metabolic rate

  47.9 to 73.8 cm3.O2/g/hr

De­vel­op­ment

Fe­male green sea tur­tles lay eggs 35-58 mm in di­am­e­ter. Like many tur­tles, green sea tur­tles' de­vel­op­ment is af­fected by tem­per­a­ture. Eggs that are laid in cooler en­vi­ron­ments less than 28.5°C tend to pro­duce more males than fe­males, and warm nests greater than 30.3°C are known to hatch more fe­males than males. Both sexes in­cu­bate in white, soft shells for 30-90 days de­pend­ing whether or not it is the wet or dry sea­son. In­cu­ba­tion typ­i­cally takes longer in the wet sea­son. Once hatch­lings leave the nest, their cara­pace is dark blue-black and about 5 cm in length. Hatch­lings av­er­age a weight of 25 g. Their plas­tron is yel­low or white, and the skin is black. As the hatch­lings ma­ture into ju­ve­niles, the will mea­sure about 40 cm in cara­pace length. Subadults mea­sure be­tween 70 to 100 cm in length. As the hatch­lings grow into ju­ve­niles, it takes 27-50 years be­fore green tur­tles reach full ma­tu­rity. (Ernst and Bar­bour, 1989; Hirth, 1997)

• Development - Life Cycle
• temperature sex determination

Re­pro­duc­tion

Green tur­tles are polyg­y­nan­drous, mean­ing that fe­males and males will have mul­ti­ple mates. Cop­u­la­tion oc­curs in the shal­low wa­ters off the shore of nest­ing beaches. When fe­males ac­cept a mate, the male will mount her and grab onto her "mat­ing notches" around her shoul­ders to as­sist in cop­u­la­tion (Hirth, 1971). Male green tur­tles also are known to join other mat­ing pairs dur­ing cop­u­la­tion by latch­ing onto other males for hours on end in at­tempts to dis­lodge the mat­ing male. The re­pro­duc­tion process usu­ally fol­lows a sys­tem such as: male searches for a fe­male mate, the male will vi­su­ally ex­am­ine and then ap­proach the fe­male, the fe­male will ei­ther sub­mit or re­ject the male,then pos­si­ble cop­u­la­tion. Cop­u­la­tion can last sev­eral hours, with the longest mount­ing episode last­ing 119 hours. Fe­male green tur­tles av­er­age a total of 15 days be­tween ini­tial mount­ing by a male to the time they at­tempt to nest on their re­spec­tive natal beaches. ("Green sea tur­tle (Ch­e­lo­nia mydas)", 2015; "South Pa­cific Is­lands-ma­rine tur­tle re­sources", 1971; "Sta­tus and dis­tri­b­u­tion of the green tur­tle, Ch­e­lo­nia mydas, in the wider Caribbean re­gion", 2001; Ernst and Bar­bour, 1989; Hirth, 1997)

• Mating System
• polygynandrous (promiscuous)

Fe­males are known to re­visit their natal beaches in 2-4 year in­ter­vals to breed from June to Sep­tem­ber. If they don't re­turn to their natal beach, they will se­lect a beach with sim­i­lar sand tex­ture and color. Hirth (1971, as cited in Carr and Ogren 1960) de­scribes pre­dictable ac­tions by fe­males when they ap­proach a nest­ing beach. Al­though they may not com­plete every ac­tion, the process usu­ally be­gins with the tur­tles ap­proach­ing the beach and se­lect­ing a suit­able nest site. The fe­males begin clear­ing the area of de­bris and dig­ging a hole with their front legs. After lay­ing eggs, the fe­males fill the nest with sand as a way to cam­ou­flage and con­ceal the eggs. Then, the fe­male tur­tles re­turn to the sea.

Fe­male green tur­tles can lay 1- 9 clutches in a sin­gle nest­ing sea­son, but tend to av­er­age around 3. Each of these clutches can in­clude 75-200 eggs. After nest­ing, it usu­ally takes 45-75 days for the eggs to hatch. The hatch­ings weigh ap­prox­i­mately 26g on av­er­age. Once the eggs hatch, the hatch­lings will begin their jour­ney to­wards the ocean. From here the hatch­lings will begin the ju­ve­nile por­tion of their life which can last 27-50 years be­fore reach­ing full ma­tu­rity. ("Green sea tur­tle (Ch­e­lo­nia mydas)", 2015; "South Pa­cific Is­lands-ma­rine tur­tle re­sources", 1971; "Sta­tus and dis­tri­b­u­tion of the green tur­tle, Ch­e­lo­nia mydas, in the wider Caribbean re­gion", 2001; Carr and Ogren, 1960; Hirth, 1997)

• Key Reproductive Features
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• oviparous

• Breeding interval

  Green sea turtles breed in 2-4 year intervals.

• Breeding season

  The nesting season for green sea turtles usually lasts from June through September.

• Range number of offspring

  75 to 200

• Average number of offspring

  136

• Average number of offspring

  150

  AnAge

• Range gestation period

  45 to 75 days

• Range age at sexual or reproductive maturity (female)

  27 to 50 years

• Range age at sexual or reproductive maturity (male)

  27 to 50 years

There is no parental in­vest­ment by green tur­tles be­yond the mother's egg-lay­ing and cam­ou­flag­ing of the nest. (Hirth, 1997)

• Parental Investment
• pre-hatching/birth
  • protecting
    • female

Lifes­pan/Longevity

There is very lit­tle re­search re­gard­ing the lifes­pan of green tur­tles, due to lack of tag­ging. How­ever, AnAge re­ported a max­i­mum green tur­tle lifes­pan of 75 years. Green tur­tles are not often held for long in cap­tiv­ity, so longevity records do not exist. ("AnAge entry for Ch­e­lo­nia mydas", 2014)

• Range lifespan
  Status: wild

  75 (high) years

• Average lifespan
  Status: captivity

  75 years

  AnAge

Be­hav­ior

Green tur­tles travel in large groups that usu­ally orig­i­nate from the same natal beach. They spend a lot of their time swim­ming, trav­el­ing about 20-90 km/day. They also can be found eat­ing, div­ing, re­pro­duc­ing, and mi­grat­ing. Ju­ve­nile green tur­tles are said to be faster swim­mers than other sea tur­tles such as log­ger­heads (Caretta caretta) and olive ri­d­leys (Lep­i­dochelys oli­vacea) due to the way green tur­tle hatch­lings stroke their fore­flip­pers.

Dur­ing the breed­ing sea­son, ac­tively mat­ing pairs are often ap­proached by sev­eral "es­cort" males that will latch on to the pair dur­ing cop­u­la­tion. Some­times these es­cort males will at­tempt to re­move the male con­nected to the fe­male. If the cop­u­lat­ing male feels threat­ened by the es­cort(s), then he might re­move him­self from the fe­male briefly to drive off the other males. Even though hu­mans are a preda­tor of green sea tur­tles, most tur­tles are not af­fected by human con­tact while swim­ming or dur­ing cop­u­la­tion. (Hirth, 1997; Semi­noff, et al., 2002)

• Key Behaviors
• natatorial
• motile
• migratory
• colonial

Home Range

Green sea tur­tles will main­tain home ranges through­out the year. These habi­tats in­clude coastal feed­ing areas dur­ing the non-breed­ing sea­son and natal beaches that the fe­males visit dur­ing the nest­ing sea­son. Adult green tur­tles have a home range that can ex­pand from 3.8 ha to 642.2 ha. They are not known to ac­tively de­fend a ter­ri­tory. (Hirth, 1997; Semi­noff, 2004)

Com­mu­ni­ca­tion and Per­cep­tion

Green tur­tles pri­mar­ily use vi­sion to de­tect plants and other prey and use vi­sual dis­plays when com­mu­ni­cat­ing. Green sea tur­tles also use a sense of wave prop­a­ga­tion di­rec­tion to help them nav­i­gate under water. Mag­netic chan­nels are also used to as­sist the ori­en­ta­tion of the tur­tle in deep wa­ters. In one study, re­searchers found that the tur­tles' inner ear can de­tect the ac­cel­er­a­tion and di­rec­tion of the wave which as­sists their sense of di­rec­tion (Lohmann and Lohmann, 1992). Fe­males use two dis­plays to com­mu­ni­cate with males whether or not they wish to mate. Fe­male green sea tur­tles will show ap­proval of a mate by being com­pletely sub­mis­sive when being mounted by the male. Fe­males will clearly re­ject a male by ei­ther swim­ming away with their hind legs closed or bit­ing a male if he gets too close. Fe­male green tur­tles also have a "re­fusal" po­si­tion, which con­sists of float­ing up­ward hav­ing their plas­tron fac­ing the male and an ex­tend­ing all limbs. (Hirth, 1997; Lohmann and Lohmann, 1996)

• Communication Channels
• visual

• Perception Channels
• visual
• vibrations
• magnetic

Food Habits

Green sea tur­tles begin their lives as om­ni­vores and grad­u­ally shift to a more her­biv­o­rous diet. As ju­ve­niles, green sea tur­tles will feast on small ma­rine in­ver­te­brates and neustonic ma­te­r­ial like sea ser­pents (Hy­dro­zoa), moss an­i­mals (Bry­ozoa), and sea hare eggs (Aplysia). They also con­sume large quan­ti­ties of wet­land plants such as api api (Avi­cen­nia schaue­ri­ana) and salt-wa­ter cord grass (Spartina al­terni­flora), which are com­monly found in salt marshes. Their diet also con­sists of a va­ri­ety of red and green algae such as: fil­a­men­tous red alga (Bostrychia), red moss (Caloglossa), fresh­wa­ter red algae (Comp­so­pogon), lob­ster horns (Poly­si­pho­nia), sea let­tuce (Ulva lac­tuca), green sea­weed (Gayralia), and crin­kle grass (Rhi­zo­clo­nium). Be­cause green sea tur­tles are highly mo­bile through­out their lives, their food choices are often op­por­tunis­tic. (Arthur, et al., 2008; Rus­sell, et al., 2011; Semi­noff, 2004; Spotila, 2004)

• Primary Diet
• omnivore

• Animal Foods
• other marine invertebrates
• zooplankton

• Plant Foods
• algae
• macroalgae

Pre­da­tion

Green tur­tle hatch­lings are at a higher risk of pre­da­tion than adult green sea tur­tles. Eggs are preyed upon by mul­ti­ple land mam­mals, rep­tiles, and crus­taceans. Some of these mam­mals in­clude: jaguars (Pan­thera onca), red foxes (Vulpes vulpes), feral dogs (Canis lupus fa­mil­iaris), golden jack­als (Canis au­reus) and hu­mans (Homo sapi­ens). Young green sea tur­tles also are con­sumed by crabs (Brachyura) and salt­wa­ter croc­o­diles (Croc­o­dy­lus porous) which can at­tack on land or in the water. The only de­fense mech­a­nism of hatch­lings is swarm­ing in large groups to­ward the ocean. Once the hatch­lings reach the water, they face a new group of preda­tors such as tiger sharks (Ga­le­o­cerdo cu­vier) and whitetip sharks (Car­charhi­nus longi­manus). Ju­ve­nile and ma­ture sea tur­tles also are preyed on by sharks. Ma­ture green sea tur­tles' best form of pro­tec­tion from their preda­tors is their large hard shell. When fe­males come on land to nest, their head and limbs be­come vul­ner­a­ble and eas­ily ac­ces­si­ble by preda­tors. Green tur­tles are also hunted by hu­mans for meat. (Al­faro, et al., 2016; Hirth, 1997; Spotila, 2004)

• Known Predators

  • saltwater crocodiles (Crocodylus porosus)
  • jaguars (Panthera onca)
  • red foxes (Vulpes vulpes)
  • golden jackals (Canis aureus)
  • feral dogs (Canis lupus familiaris)
  • whitetip sharks (Carcharhinus longimanus)
  • tiger sharks (Galeocerdo cuvier)
  • humans (Homo sapiens)
  • crabs (Brachyura)

Ecosys­tem Roles

Ju­ve­nile green tur­tles are preda­tors of sea ser­pents (Hy­dro­zoa), moss an­i­mals (Bry­ozoa), sea hare eggs (Aplysia) and small jel­ly­fish (Medu­soza). Ma­ture green tur­tles are mostly her­biv­o­rous and con­sume large quan­ti­ties of sea grass and algae. Green tur­tles play a role in their ecosys­tem by fa­cil­i­tat­ing nu­tri­ent turnover and sea grass re­growth. As the tur­tles graze on sea grass, they pro­vide ni­tro­gen-rich fer­til­izer in the form of fecal mat­ter. Green sea tur­tles suf­fer from par­a­sitic trema­tode eggs known as flukes. These trema­todes cause in­flamed car­dio­vas­cu­lar tis­sue that in­fect tur­tles and com­monly re­sult in death. Species of flukes that are found in green tur­tles in­clude: Learedius leardei, Caret­ta­cola hawai­ien­sis, Ha­palotrema dor­so­pora, and Ha­palotrema pos­torchis. (Aguirre, et al., 1998; Aragones, et al., 2006; Spotila, 2004)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Al­though many coun­tries have es­tab­lished laws pro­tect­ing sea tur­tles, green sea tur­tles are still poached for their eggs and meat in cer­tain areas around the world, such as South East Asia. The shells are also dis­played as dec­o­ra­tion or used to make jew­elry. ("Green sea tur­tle (Ch­e­lo­nia mydas)", 2015; Mar­co­valdi and Mar­co­valdi, 1999; Spotila, 2004)

• Positive Impacts
• food
• body parts are source of valuable material

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse ef­fects of Ch­e­lo­nia mydas on hu­mans.

Con­ser­va­tion Sta­tus

Green tur­tles are con­sid­ered an en­dan­gered species ac­cord­ing to the IUCN Red List. The Con­ven­tion on In­ter­na­tional Trade in En­dan­gered Species clas­si­fies green sea tur­tles under Ap­pen­dix I which in­clude species that are most en­dan­gered and most at risk of ex­tinc­tion. This spe­cific ap­pen­dix ex­plains that trade of this species is pro­hib­ited un­less the species is being used for re­search. Ex­cep­tions to this pro­hi­bi­tion are only valid under ap­proval of im­port and ex­port per­mits.

The United States Fed­eral List clas­si­fies some green sea tur­tles as en­dan­gered, but a ma­jor­ity of pop­u­la­tions are clas­si­fied as threat­ened. Those con­sid­ered en­dan­gered were found to live in the Mediter­ranean pop­u­la­tions, Cen­tral West Pa­cific pop­u­la­tions, and Cen­tral South Pa­cific pop­u­la­tions. This dan­ger­ous de­cline in pop­u­la­tion is mostly due to ma­rine fish­eries catch­ing ma­ture and ju­ve­nile green tur­tles in for­ag­ing areas and on nest­ing grounds. Fish­ing tech­niques in­clude har­poon­ing, catch­ing by hand, net­ting, noos­ing, turn­ing the tur­tle over on their dor­sal side and var­i­ous other tech­niques. Green tur­tles are also threat­ened by the pres­ence of ar­ti­fi­cial light. This is seen as a se­ri­ous threat, be­cause sea tur­tles some­times mis­take ar­tif­i­cal light for sun­light. It has been sug­gested that ar­tif­i­cal light dis­ori­en­tates green tur­tles, and af­fects both their gen­eral and nest­ing be­hav­ior. Spe­cific ef­fects of ar­ti­fi­cial light on these tur­tles in­clude al­tered adult re­turn crawl and in­com­plete nest con­struc­tion.

In ef­forts to con­serve this tur­tle species, laws have been made and have suc­cess­fully less­ened the threats by fish­eries. For in­stance, both the U.S. Fish and Wildlife Ser­vice and Na­tional Ma­rine Fish­eries Ser­vice en­force the laws pro­hibit­ing the cap­ture of sea tur­tles on land and in water. Other con­tracts that have ben­e­fit the con­ser­va­tion of green tur­tles in­clude the Mem­o­ran­dum of Un­der­stand­ing on ASEAN Sea Tur­tle Con­ser­va­tion and Pro­tec­tion, the Mem­o­ran­dum of Un­der­stand­ing Con­cern­ing Con­ser­va­tion Mea­sures for Ma­rine Tur­tles of the At­lantic Coast of Africa, and the In­ter-Amer­i­can Con­ven­tion for the Pro­tec­tion and Con­ser­va­tion of Sea Tur­tles. Even though these agree­ments have made a pos­i­tive im­pact on the lifes­pan and pop­u­la­tion of green tur­tles, this species is still in dan­ger of near-shore fish­eries. (Ernst and Bar­bour, 1989; Hirth, 1997; Semi­noff, 2004; With­er­ing­ton, 1992)

• IUCN Red List

  Endangered
  More information

• IUCN Red List

  Endangered
  More information

• US Federal List

  Endangered Threatened

• CITES

  Appendix I

• State of Michigan List

  No special status

Con­trib­u­tors

Kenda­lyn Hersh (au­thor), Rad­ford Uni­ver­sity, Alex At­wood (ed­i­tor), Rad­ford Uni­ver­sity, Marisa Dameron (ed­i­tor), Rad­ford Uni­ver­sity, Karen Pow­ers (ed­i­tor), Rad­ford Uni­ver­sity, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

2014. "AnAge entry for Ch­e­lo­nia mydas" (On-line). AnAge: The An­i­mal Age­ing and Longevity Data­base. Ac­cessed Oc­to­ber 27, 2016 at http://​genomics.​senescence.​info/​species/​entry.​php?​species=Chelonia_​mydas.

United States Fish and Wild Life Ser­vice. Green sea tur­tle (Ch­e­lo­nia mydas). None. Jack­sonville, Florida and Ar­ling­ton, Vir­ginia: United States Fish and Wildlife Ser­vice. 2015. Ac­cessed Sep­tem­ber 20, 2016 at https://​www.​fws.​gov/​northflorida/​SeaTurtles/​Turtle%20Factsheets/​green-sea-turtle.​htm.

Food and Agri­cul­ture Or­ga­ni­za­tion, United Na­tions. South Pa­cific Is­lands-ma­rine tur­tle re­sources. None. Rome, Italy: None. 1971.

Wildlife Con­ser­va­tion So­ci­ety. Sta­tus and dis­tri­b­u­tion of the green tur­tle, Ch­e­lo­nia mydas, in the wider Caribbean re­gion. None. Santo Domingo, Do­mini­can Re­pub­lic: In­ter­na­tional Union for Con­ser­va­tion of Na­ture. 2001.

Na­tional Ma­rine Fish­eries Ser­vice. The anatomy of sea tur­tles. NMFS-SEFSC-470. Miami, Florida: U.S. De­part­ment of Com­merce NOAA Tech­ni­cal Mem­o­ran­dum. 2001. Ac­cessed Sep­tem­ber 15, 2016 at http://​s3.​amazonaws.​com/​academia.​edu.​documents/​41147367/​Wyneken2002AnatOfSeaTurtles.​pdf?​AWSAccessKeyId=AKIAJ56TQJRTWSMTNPEA&​Expires=1473950906&​Signature=MBXAG6x7%2F3%2B8A1KWdacU1Hu%2BZX8%3D&​response-content-disposition=inline%3B%20filename%3DAnatomy_​of_​Sea_​Turtles.​pdf.

Aguirre, A., T. Spraker, G. Bal­azs, B. Zim­mer­man. 1998. Spirorchidi­a­sis and fi­bropa­pil­lo­mato­sis in green tur­tles from the Hawai­ian is­lands. Jour­nal of Wildlife Dis­eases, 34/1: 91-98.

Al­faro, L., V. Mon­tal, F. Guimaraes, C. Saenz, J. Cruz, F. Morazan, E. Car­rillo. 2016. Char­ac­ter­i­za­tion of at­tack events on sea tur­tles (Ch­e­lo­nia mydas and Lep­i­dochelys oli­vacea) by jaguar (Pan­thera onca) in Naranjo Sec­tor, Santa Rosa Na­tional Park, Costa Rica. In­ter­na­tional Jour­nal of Con­ser­va­tion Sci­ence, 7/1: 101-108.

Aragones, L., I. Lawler, W. Foley, H. Marsh. 2006. Dugong graz­ing and tur­tle crop­ping: graz­ing op­ti­miza­tion in trop­i­cal sea­grass sys­tems. Oe­colo­gia, 149/4: 635-647.

Arthur, K., M. Boyle, C. Lim­pus. 2008. On­to­ge­netic changes in diet and habi­tat use in green sea tur­tle (Ch­e­lo­nia mydas) life his­tory. Ma­rine Ecol­ogy Progress Se­ries, 362: 303-311.

Bjorn­dal, K., A. Bolten, M. Chaloupka. 2000. Green tur­tle so­matic growth model: Ev­i­dence for den­sity de­pen­dence. Eco­log­i­cal Ap­pli­ca­tions, 10/1: 269-282.

Booth, J., J. Pe­ters. 1972. Be­hav­ioural stud­ies on the green tur­tle (Ch­e­lo­nia mydas) in the sea. An­i­mal Be­hav­iour, 20/4: 811-812.

Burk­holder, D., M. Hei­thaus, J. Thom­son, J. Fourqurean. 2011. Di­ver­sity in trophic in­ter­ac­tions of green sea tur­tles Ch­e­lo­nia mydas on a rel­a­tively pris­tine coastal for­ag­ing ground. Ma­rine Ecol­ogy Progress Se­ries, 439: 277-293.

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