{{Short description|Species of turtle}} {{Redirect|Arrau|the pianist|Claudio Arrau}} {{Use dmy dates|date=February 2021}} {{Speciesbox | image = Podocnemis expansa INPA.jpg | image2 = Podocnemis expansa head from Venezolana.jpg | status = LR/cd | status_system = IUCN2.3 | status_ref = <ref name=iucn>{{cite journal | author = Tortoise & Freshwater Turtle Specialist Group | title = ''Podocnemis expansa'' | journal = The IUCN Red List of Threatened Species | volume = 1996 | page = e.T17822A97397263 | publisher = IUCN | date = 1996 | doi = 10.2305/IUCN.UK.1996.RLTS.T17822A7500662.en | doi-access = free }}</ref> | status2 = CITES_A2 | status2_system = CITES | status2_ref = <ref name="CITES">{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref> | genus = Podocnemis | species = expansa | authority = (Schweigger, 1812) | range_map = Arrau (Podocnemis expansa).PNG | synonyms = *''Emys expansa'' Schweigger, 1812 *''Emys amazonica'' Spix, 1824 *''Podocnemis expansa'' Wagler, 1830 *''Emys arrau'' Schinz, 1833 }}
The '''Arrau turtle''' ('''''Podocnemis expansa'''''), also known as the '''South American river turtle''', '''giant South American turtle''', '''giant Amazon River turtle''', '''Arrau sideneck turtle''', '''Amazon River turtle''' or simply the '''Arrau''',<ref name=iucn/><ref>[http://reptile-database.reptarium.cz/species?genus=Podocnemis&species=expansa&search_param=%28%28genus%3D%27Podocnemis%27%2Cexact%29%29 ''Podocnemis expansa''], The Reptile Database</ref><ref name=Rhodin2017>{{cite journal| url=http://images.turtleconservancy.org/documents/2017/crm-7-checklist-atlas-v8-2017.pdf |title=Turtles of the world, 2017 update: Annotated checklist and atlas of taxonomy, synonymy, distribution, and conservation status(8th Ed.)| journal=Chelonian Research Monographs| volume=7| access-date=4 October 2019| date=3 August 2017| last1=Rhodin | first1=Anders G.J. |last2=Inverson |first2=John B. |last3=Roger |first3=Bour |last4=Fritz |first4=Uwe |last5=Georges |first5=Arthur |last6=Shaffer |first6=H. Bradley |last7=van Dijk |first7=Peter Paul| collaboration=Turtle Taxonomy Working Group| series=Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group| edition=8| editor1=Rhodin A. G.J. |editor2=Iverson J.B. |editor3=van Dijk P.P. |editor4=Saumure R.A. |editor5=Buhlmann K.A. |editor6=Pritchard P.C.H. |editor6-link=Peter Pritchard |editor7=Mittermeier R.A. |editor7-link=Russell Mittermeier | pages=1–292| isbn=978-1-5323-5026-9| doi=10.3854/crm.7.checklist.atlas.v8.2017}}</ref><ref name=Rivas2015>{{cite web| author=Rivas, D. | title=''Podocnemis expansa'' (Arrau Sideneck Turtle) | url=https://sta.uwi.edu/fst/lifesciences/documents/Podocnemis_expansa.pdf | series=The Online Guide to the Animals of Trinidad and Tobago | year=2015 | access-date=28 September 2017}}</ref> is the largest of the side-neck turtles (Pleurodira) and the largest freshwater turtle in Latin America.<ref name=Rivas2015/> The species primarily feeds on plant material and typically nests in large groups on beaches.<ref name=Rivas2015/> Due to hunting of adults, collecting of their eggs, pollution, habitat loss, and dams, the Arrau turtle is seriously threatened.<ref name=Rivas2015/><ref name=Mogollones2010>{{cite journal| author=Mogollones, S.C.| author2=D.J. Rodriguez| author3=O. Hernandez| author4=G.R. Barreto| name-list-style=amp | year=2010 | title=A Demographic Study of the Arrau Turtle (''Podocnemis expansa'') in the Middle Orinoco River, Venezuela | journal=Chelonian Conservation and Biology | volume=9 | issue=1 | pages=79–89 | doi=10.2744/CCB-0778.1 | s2cid=86083211| doi-access=free }}</ref><ref name=Overduin2015>{{cite web | author=Overduin, M. | title=More Than 1,000 Turtles and Nests Protected in Colombia | url=http://www.turtlesurvival.org/blog/1/372#.Wc2YcEnU_IU | publisher=Turtle Survival Alliance | date=2 September 2015 | access-date=28 September 2017 | archive-url=https://web.archive.org/web/20180830174315/http://www.turtlesurvival.org/blog/1/372#.Wc2YcEnU_IU | archive-date=30 August 2018 | url-status=dead }}</ref><ref name=Vanzolini2003>{{cite journal| author=Vanzolini, P.E. | year=2003 | title=On clutch size and hatching success of the South American turtles ''Podocnemis expansa'' (Schweigger, 1812) and P. unifilis Troschel, 1848 (Testudines, Podocnemididae) | url=http://www.scielo.br/pdf/aabc/v75n4/a02v75n4.pdf | journal=Anais da Academia Brasileira de Ciências | volume=75 | issue=4 | pages=415–430 | doi=10.1590/s0001-37652003000400002| pmid=14605677 | doi-access=free }}</ref>
==Range and habitat== Arrau turtles are found in the Amazon, Orinoco and Essequibo basins in Brazil, Bolivia, Peru, Ecuador, Colombia, Venezuela and Guyana.<ref name=Rhodin2017/> On occasion, typically after floods, individuals turn up in Trinidad.<ref name=Rivas2015/> They are found in deep rivers, ponds, freshwater lagoons and flooded forest<ref name=Rivas2015/> in white-, black- and clear-water.<ref name=Alves2008>{{cite journal| author=Alves, R.R.N.| author2=G.G. Santana| name-list-style=amp | year=2008 | title=Use and commercialization of ''Podocnemis expansa'' (Schweiger 1812) (Testudines: Podocnemididae) for medicinal purposes in two communities in North of Brazil | journal=Journal of Ethnobiology and Ethnomedicine | volume=4 | issue=3 | pages=3| doi=10.1186/1746-4269-4-3 | pmid=18208597| pmc=2254592 | doi-access=free}}</ref>
==Appearance== [[File:Podocnemis expansa 36879203 (cropped).jpg|left|thumb|Basking in Colombia]] Arrau turtles can reach up to {{convert|90|kg|lb|abbr=on}} in weight and the carapace length is up to {{convert|1.07|m|ft|abbr=on}}.<ref name="INCTCENBAM">{{cite web| title=''Podocnemis expansa'' | url=https://ppbio.inpa.gov.br/en/Cheloniateca/Podocnemis_expansa | publisher=INCT CENBAM, INPA | access-date=28 September 2017}}</ref> Most individuals are considerably smaller with the average adult female having a carapace length of {{convert|64-71|cm|ft|abbr=on|1}} and the average adult male {{convert|40-50|cm|ft|abbr=on|1}}.<ref name="Rivas2015" /> In addition to an overall smaller size, males can be recognized by their longer tail and straighter carapace than the females.<ref name="INCTCENBAM" />
Arrau turtles are brown, gray or olive-green,<ref name="INCTCENBAM" /> but the exact color varies depending on the algae growing on the carapace.<ref name="Rivas2015" />
==Behavior== ===Feeding=== Adult Arrau turtles feed almost entirely on plant material such as fruits, seeds, leaves, legumes and algae,<ref name="Rivas2015" /><ref name="INCTCENBAM" /> but may also take freshwater sponges, eggs and carcasses of dead animals (such as dead fish).<ref name="Rivas2015" /> Captives have been recorded feeding on meat.<ref name="INCTCENBAM" /><ref name="OregonZoo" /> Juveniles feed on fish and plant material.<ref name="Rivas2015" /> The species is mainly active during the day.<ref name="Rivas2015" />
===Breeding and life cycle=== thumb|Young in Venezuela|left
When nearing the breeding season, Arrau turtles migrate to certain sites where the eggs are laid.<ref name="INCTCENBAM" /> In some locations, nesting occurs in large groups on beaches,<ref name="INCTCENBAM" /> which reduces the risk posed by predators.<ref name="Rivas2015" /> Some beaches have as many as 500 nesting females.<ref name="OregonZoo">{{cite web | author=Rivas, D. | title=Arrau turtle | url=http://www.oregonzoo.org/discover/animals/arrau-turtle | publisher=Oregon Zoo | access-date=28 September 2017 | archive-url=https://web.archive.org/web/20170929092310/http://www.oregonzoo.org/discover/animals/arrau-turtle | archive-date=29 September 2017 | url-status=dead }}</ref> Mating occurs in the water.<ref name="OregonZoo" /> During and just before the nesting season the species frequently basks, typically in groups. It is suspected that the additional heat accelerates the ovulation in the females.<ref name="Ferrara2010">{{cite journal| author=Ferrara, C.R.| author2=L. Schneider| author3=R.C. Vogt| name-list-style=amp | year=2010 | title=''Podocnemis expansa'' (Giant South American River Turtle). Basking before the nesting season | url=https://www.researchgate.net/publication/293365145 }}</ref> At other times the species is generally not found on land.<ref name="Ferrara2010" /> When on land, it is usually very shy and retreats to the water at the slightest hint of danger.<ref name="Rivas2015" />
The female lays an average of 75–123 eggs (average varies depending on region),<ref name="Vanzolini2003" /> which are placed during the night in a {{convert|60-80|cm|ft|abbr=on}} deep nest that is dug on the beach.<ref name="Rivas2015" /> The eggs are laid during the low water season and hatch as the water starts to rise. If it rises too fast or too early, the nest is flooded and the young die within the eggs.<ref name="Vanzolini2003" /> As long as nests are not dug up by predators, the hatching success rate is usually high, averaging at 83%.<ref name="Vanzolini2003" />
The eggs hatch after about 50 days and the sex of the young depends on the nest temperature (females at higher temperatures, males at lower).<ref name="Rivas2015" /><ref name="INCTCENBAM" /> When hatching, the young are around {{convert|5|cm|in|abbr=on|0}} long and dart directly for the water, but they emerge to the attentions of many predators so that only about five percent ever reach the adult feeding grounds.<ref>The Simon and Schuster Encyclopedia of Animals</ref> When hatching, the females emit sounds which attract the young; they stay together for a period in the flooded forests.<ref name="Ferrara2014">{{cite journal| author=Ferrara, C.R.| author2=R.C. Vogt| author3=R.S. Sousa-Lima| author4=B.M.R. Tardio| author5= V.C.D. Bernardes| name-list-style=amp| year=2014 | title=Sound Communication and Social Behavior in an Amazonian River Turtle (''Podocnemis expansa'') | journal=Herpetologica | volume=70 | issue=2 | pages=149–156 | doi=10.1655/HERPETOLOGICA-D-13-00050R2 | s2cid=85899110}}</ref> Vocalizations appear to play an important role in the social life of this turtle and in addition to the "connect to newly hatched young" sound, four primary sounds have been documented during the nesting season: one used during migration, one before basking, one when nesting at night and finally one when in the water after nesting.<ref name="Ferrara2014" />
They can reach an age of 20 years or more in the wild, and captives have lived for at least 25 years.<ref name="Rivas2015" /> Based on certain scientific models it has been estimated that the largest individuals perhaps are as old as 80 years.<ref name="Hernandez2006">{{cite journal| author=Hernandez, O.| author2=R. Espín| name-list-style=amp | year=2006 | title=Efectos del reforzamiento sobre la población de Tortuga Arrau (''Podocnemis expansa'') en el Orinoco medio, Venezuela | journal=Interciencia | volume=31 | pages=424–430|url=http://ve.scielo.org/scielo.php?script=sci_arttext&pid=S0378-18442006000600008}}</ref>
==Conservation status== [[File:Podocnemis expansa in Zoo Krefeld (1).JPG|thumb|Adult at Krefeld Zoo, Germany]]thumb|Facility for raising Arrau turtles in Venezuela
The Arrau turtle is widespread and was not considered threatened overall by the IUCN in 1996 (the year of the last full review),<ref name=iucn/> but it has declined drastically,<ref name=Ferrara2010/> and a draft review by the IUCN Species Survival Commission—Tortoise and Freshwater Turtle Specialist Group in 2011 recommended that it should be considered critically endangered.<ref name=Rhodin2017/> The species is slow to mature; some have suggested that females reach maturity when 4–8 years old<ref name=Rivas2015/> and others have suggested about 17 years old.<ref name=Hernandez2006/> Their social behavior, especially at certain nesting beaches, makes them and their eggs vulnerable to humans.<ref name=Rivas2015/> In addition to being used for food, they are sometimes used in traditional medicine.<ref name=Alves2008/> At the main known nesting beaches, it is estimated that the number of nests fell from 34,000 in 1963 to 4,700 in 1981.<ref name=Rivas2015/> In the middle Orinoco River alone, it is estimated that as many as 330,000 nested in 1800, but less than half this number nested in 1945 and by the early 2000s (decade) it had fallen to 700–1300.<ref name=Mogollones2010/> In addition to hunting and collecting of their eggs, threats include pollution, habitat loss,<ref name=Rivas2015/> and dams, which can cause flooding of nest sites.<ref name=Vanzolini2003/> Several countries in their range have implemented laws protecting the species, but hunting and egg collection (even if illegal) continues.<ref name=Penaloza2015>{{cite journal| author=Peñaloza, C.L.| author2=O. Hernandez| author3=R. Espín| name-list-style=amp | year=2015 | title=Head-starting the Giant Sideneck River Turtle (''Podocnemis expansa''): Turtles and People in the Middle Orinoco, Venezuela | journal=Herpetological Conservation and Biology | volume=10 | pages=472–488|url=http://www.herpconbio.org/Volume_10/Symposium/Penaloza_etal_2015.pdf }}</ref><ref name=Lima2014>{{cite journal| author=Pantoja-Lima| author2=Aride| author3=de Oliveira| author4=Félix-Silva| author5=Pezzuti| author6=Rebêlo| name-list-style=amp | year=2014 | title=Chain of commercialization of ''Podocnemis'' spp. turtles (Testudines: Podocnemididae) in the Purus River, Amazon basin, Brazil: current status and perspectives | journal=J Ethnobiol Ethnomed | volume=10 | issue=8 | pages=8| doi=10.1186/1746-4269-10-8 | pmc=3933064 |pmid=24467796| doi-access=free}}</ref> A number of conservation projects have been initiated. For example, 54 nesting beaches have been protected in Brazil,<ref name=Rivas2015/> beaches used by more than 1,000 females are protected in Colombia,<ref name=Overduin2015/> and since the mid-1990s many thousand eggs have been collected in Venezuela for safe incubation, the hatchlings "headstarted" (getting them through the most dangerous period) and then released.<ref name=Mogollones2010/><ref name=Penaloza2015/> All species in the genus ''Podocnemis'' are listed on CITES Appendix II.<ref name=Rhodin2017/>
The slow growth limits its potential for major commercial turtle farming.<ref name=Lima2014/> Nevertheless, about 880,000 turtles of various species were kept at 92 farms (both ones that are commercial and ones with conservation purpose) in 2004 in Brazil alone,<ref name=Sa2004>{{cite journal| author=Sá| author2=Quintanilha| author3=Freneau| author4=Luz| author5=Borja| author6=Silva| name-list-style=amp | year=2004 | title=Crescimento ponderal de filhotes de tartaruga gigante da Amazônia (''Podocnemis expansa'') submetidos a tratamento com rações isocalóricas contendo diferentes níveis de proteína bruta | journal=Revista Brasileira de Zootecnia | volume=33 | issue=6 | doi=10.1590/S1516-35982004000900022 | pages=2351–2358| doi-access=free}}</ref> and some of these keep Arrau turtles, also in semi-intensive farm systems.<ref name=Aguiar2017>{{cite journal| author= Aguiar, J.C.| author2= E.A. Adriano| author3= P.D. Mathews| name-list-style= amp | year=2017 | title=Morphology and molecular phylogeny of a new ''Myxidium'' species (Cnidaria: Myxosporea) infecting the farmed turtle ''Podocnemis expansa'' (Testudines: Podocnemididae) in the Brazilian Amazon | journal=Parasitology International | volume=66 | issue=1 | pages=825–830 | doi=10.1016/j.parint.2016.09.013| pmid= 27693559}}</ref>
==References== {{Reflist}}
==External links== * {{cite journal| author1=Forero-Medina, G.| display-authors=etal | year=2019 | title=On the future of the giant South American river turtle Podocnemis expansa | journal=Oryx | volume=55 | pages=1–8 | doi=10.1017/S0030605318001370 | doi-access=free }}
==External links== {{Commons category|Podocnemis expansa}} {{Wikispecies|Podocnemis expansa}}
{{Pleurodira}} {{Testudines}} {{Taxonbar|from=Q2625714}}
Category:Podocnemis Category:Turtles of South America Category:Fauna of the Amazon Category:Reptiles of Bolivia Category:Turtles of Brazil Category:Reptiles of Colombia Category:Reptiles of Ecuador Category:Reptiles of Guyana Category:Reptiles of Peru Category:Reptiles of Venezuela Category:Reptiles described in 1812